Freescale Semiconductor, Inc...
Freescale Semiconductor, Inc.
MCF5307 ColdFire®
Integrated Microprocessor
User’s Manual
MCF5307UM/D
Rev. 2.0, 08/2000
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Freescale Semiconductor, Inc...
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I2C is a registered trademark of Philips Semiconductors
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consequential or incidental damages. “Typical” parameters which may be provided in Motorola data sheets and/or specifications can
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Overview
Part I: MCF5307 Processor Core
Part I
ColdFire Core
2
Hardware Multiply/Accumulate (MAC) Unit
3
Local Memory
4
Debug Support
5
Part II: System Integration Module (SIM)
Freescale Semiconductor, Inc...
1
Part II
SIM Overview
6
Phase-Locked Loop (PLL)
7
2
I C Module
8
Interrupt Controller
9
Chip-Select Module
10
Synchronous/Asynchronous DRAM Controller Module
11
Part III: Peripheral Module
Part III
DMA Controller Module
12
Timer Module
13
UART Modules
14
Parallel Port (General-Purpose I/O)
15
Part IV: Hardware Interface
Part IV
Mechanical Data
16
Signal Descriptions
17
Bus Operation
18
IEEE 1149.1 Test Access Port (JTAG)
19
Electrical Specifications
20
Appendix: Memory Map
A
Glossary of Terms and Abbreviations
GLO
Index
IND
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IND
B
GLO
IND
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1
Part I
Part I: MCF5307 Processor Core
2
ColdFire Core
3
Hardware Multiply/Accumulate (MAC) Unit
4
Local Memory
5
Debug Support
Part II
Freescale Semiconductor, Inc...
Overview
Part II: System Integration Module (SIM)
6
SIM Overview
7
Phase-Locked Loop (PLL)
8
I2C Module
9
Interrupt Controller
10
Chip-Select Module
11
Synchronous/Asynchronous DRAM Controller Module
Part III
Part III: Peripheral Module
12
DMA Controller Module
13
Timer Module
14
UART Modules
15
Parallel Port (General-Purpose I/O)
Part IV
Part IV: Hardware Interface
16
Mechanical Data
17
Signal Descriptions
18
Bus Operation
19
IEEE 1149.1 Test Access Port (JTAG)
20
Electrical Specifications
A
Appendix B: Memory Map
GLO
Glossary of Terms and Abbreviations
IND
Index
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CONTENTS
Paragraph
Number
Title
Page
Number
Freescale Semiconductor, Inc...
About This Book
Chapter 1
Overview
1.1
1.2
1.2.1
1.3
1.3.1
1.3.1.1
1.3.1.2
1.3.1.3
1.3.1.4
1.3.1.5
1.3.1.6
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.3.7.1
1.3.7.2
1.3.7.3
1.3.7.4
1.3.7.5
1.3.8
1.3.9
1.4
1.4.1
1.4.2
1.4.3
1.4.4
Features ............................................................................................................... 1-1
MCF5307 Features.............................................................................................. 1-4
Process ............................................................................................................ 1-6
ColdFire Module Description ............................................................................. 1-7
ColdFire Core ................................................................................................. 1-7
Instruction Fetch Pipeline (IFP).................................................................. 1-7
Operand Execution Pipeline (OEP) ............................................................ 1-7
MAC Module.............................................................................................. 1-7
Integer Divide Module................................................................................ 1-7
8-Kbyte Unified Cache ............................................................................... 1-8
Internal 4-Kbyte SRAM ............................................................................. 1-8
DRAM Controller ........................................................................................... 1-8
DMA Controller.............................................................................................. 1-8
UART Modules............................................................................................... 1-8
Timer Module ................................................................................................. 1-9
I2C Module ..................................................................................................... 1-9
System Interface ........................................................................................... 1-10
External Bus Interface .............................................................................. 1-10
Chip Selects .............................................................................................. 1-10
16-Bit Parallel Port Interface .................................................................... 1-10
Interrupt Controller ................................................................................... 1-10
JTAG......................................................................................................... 1-11
System Debug Interface................................................................................ 1-11
PLL Module.................................................................................................. 1-11
Programming Model, Addressing Modes, and Instruction Set......................... 1-12
Programming Model ..................................................................................... 1-13
User Registers ............................................................................................... 1-14
Supervisor Registers ..................................................................................... 1-14
Instruction Set ............................................................................................... 1-15
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CONTENTS
Paragraph
Number
Title
Page
Number
Part I
MCF5407 Processor Core
Freescale Semiconductor, Inc...
Chapter 2
ColdFire Core
2.1
2.1.1
2.1.2
2.1.2.1
2.1.2.1.1
2.1.2.2
2.1.2.2.1
2.1.2.2.2
2.1.2.2.3
2.1.3
2.2
2.2.1
2.2.1.1
2.2.1.2
2.2.1.3
2.2.1.4
2.2.1.5
2.2.2
2.2.2.1
2.2.2.2
2.2.2.3
2.2.2.4
2.2.2.5
2.2.2.6
2.3
2.4
2.4.1
2.4.2
2.5
2.6
2.6.1
2.7
2.7.1
2.7.2
2.7.3
2.7.4
vi
Features and Enhancements..............................................................................
Clock-Multiplied Microprocessor Core........................................................
Enhanced Pipelines .......................................................................................
Instruction Fetch Pipeline (IFP)................................................................
Branch Acceleration .............................................................................
Operand Execution Pipeline (OEP) ..........................................................
Illegal Opcode Handling.......................................................................
Hardware Multiply/Accumulate (MAC) Unit ......................................
Hardware Divide Unit ..........................................................................
Debug Module Enhancements ......................................................................
Programming Model .........................................................................................
User Programming Model ............................................................................
Data Registers (D0–D7) ...........................................................................
Address Registers (A0–A6) ......................................................................
Stack Pointer (A7, SP)..............................................................................
Program Counter (PC) ..............................................................................
Condition Code Register (CCR)...............................................................
Supervisor Programming Model...................................................................
Status Register (SR)..................................................................................
Vector Base Register (VBR) ....................................................................
Cache Control Register (CACR) ..............................................................
Access Control Registers (ACR0–ACR1)................................................
RAM Base Address Register (RAMBAR) ...............................................
Module Base Address Register (MBAR) .................................................
Integer Data Formats.........................................................................................
Organization of Data in Registers.....................................................................
Organization of Integer Data Formats in Registers ......................................
Organization of Integer Data Formats in Memory .......................................
Addressing Mode Summary .............................................................................
Instruction Set Summary...................................................................................
Instruction Set Summary ..............................................................................
Instruction Timing ............................................................................................
MOVE Instruction Execution Times ............................................................
Execution Timings—One-Operand Instructions ..........................................
Execution Timings—Two-Operand Instructions..........................................
Miscellaneous Instruction Execution Times.................................................
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2-21
2-22
2-22
2-23
2-23
2-24
2-24
2-24
2-25
2-25
2-26
2-27
2-27
2-27
2-28
2-28
2-28
2-29
2-29
2-30
2-30
2-31
2-31
2-31
2-31
2-31
2-31
2-32
2-33
2-34
2-37
2-40
2-41
2-43
2-43
2-45
Freescale Semiconductor, Inc.
CONTENTS
Paragraph
Number
2.7.5
2.8
2.8.1
2.8.2
Title
Page
Number
Branch Instruction Execution Times ............................................................
Exception Processing Overview .......................................................................
Exception Stack Frame Definition................................................................
Processor Exceptions ....................................................................................
2-46
2-47
2-49
2-50
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Chapter 3
Hardware Multiply/Accumulate (MAC) Unit
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.2
Overview.............................................................................................................
MAC Programming Model.............................................................................
General Operation...........................................................................................
MAC Instruction Set Summary ......................................................................
Data Representation........................................................................................
MAC Instruction Execution Timings..................................................................
3-1
3-2
3-3
3-4
3-4
3-5
Chapter 4
Local Memory
4.1
4.2
4.3
4.4
4.4.1
4.5
4.5.1
4.6
4.7
4.8
4.8.1
4.8.2
4.9
4.9.1
4.9.1.1
4.9.1.2
4.9.1.3
4.9.2
4.9.3
4.9.3.1
4.9.3.2
4.9.3.3
4.9.3.4
4.9.4
Interactions between Local Memory Modules ................................................... 4-1
SRAM Overview ................................................................................................ 4-1
SRAM Operation ................................................................................................ 4-2
SRAM Programming Model............................................................................... 4-3
SRAM Base Address Register (RAMBAR)................................................... 4-3
SRAM Initialization............................................................................................ 4-4
SRAM Initialization Code .............................................................................. 4-5
Power Management ............................................................................................ 4-6
Cache Overview.................................................................................................. 4-6
Cache Organization............................................................................................. 4-7
Cache Line States: Invalid, Valid-Unmodified, and Valid-Modified............. 4-8
The Cache at Start-Up..................................................................................... 4-9
Cache Operation................................................................................................ 4-11
Caching Modes ............................................................................................. 4-13
Cacheable Accesses .................................................................................. 4-13
Write-Through Mode ............................................................................... 4-14
Copyback Mode ....................................................................................... 4-14
Cache-Inhibited Accesses ............................................................................. 4-14
Cache Protocol.............................................................................................. 4-15
Read Miss ................................................................................................. 4-15
Write Miss ............................................................................................... 4-16
Read Hit .................................................................................................... 4-16
Write Hit .................................................................................................. 4-16
Cache Coherency ......................................................................................... 4-17
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CONTENTS
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Paragraph
Number
4.9.5
4.9.5.1
4.9.5.2
4.9.5.2.1
4.9.5.2.2
4.9.6
4.10
4.10.1
4.10.2
4.11
4.12
4.12.1
4.13
Title
Page
Number
Memory Accesses for Cache Maintenance...................................................
Cache Filling.............................................................................................
Cache Pushes ............................................................................................
Push and Store Buffers .........................................................................
Push and Store Buffer Bus Operation...................................................
Cache Locking ..............................................................................................
Cache Registers.................................................................................................
Cache Control Register (CACR) ..................................................................
Access Control Registers (ACR0–ACR1)....................................................
Cache Management...........................................................................................
Cache Operation Summary ...............................................................................
Cache State Transitions ................................................................................
Cache Initialization Code..................................................................................
4-17
4-17
4-18
4-18
4-18
4-19
4-21
4-21
4-22
4-24
4-25
4-25
4-29
Chapter 5
Debug Support
5.1
5.2
5.3
5.3.1
5.4
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.5
5.5.1
5.5.2
5.5.2.1
5.5.2.2
5.5.3
5.5.3.1
5.5.3.1.1
5.5.3.2
5.5.3.3
5.5.3.3.1
5.5.3.3.2
5.5.3.3.3
viii
Overview............................................................................................................. 5-1
Signal Description............................................................................................... 5-2
Real-Time Trace Support.................................................................................... 5-3
Begin Execution of Taken Branch (PST = 0x5) ............................................. 5-4
Programming Model ........................................................................................... 5-5
Address Attribute Trigger Register (AATR) .................................................. 5-7
Address Breakpoint Registers (ABLR, ABHR) ............................................ 5-8
BDM Address Attribute Register (BAAR)..................................................... 5-9
Configuration/Status Register (CSR)............................................................ 5-10
Data Breakpoint/Mask Registers (DBR, DBMR)......................................... 5-12
Program Counter Breakpoint/Mask Registers (PBR, PBMR)...................... 5-13
Trigger Definition Register (TDR) ............................................................... 5-14
Background Debug Mode (BDM) .................................................................... 5-16
CPU Halt....................................................................................................... 5-16
BDM Serial Interface.................................................................................... 5-17
Receive Packet Format ............................................................................. 5-19
Transmit Packet Format............................................................................ 5-19
BDM Command Set...................................................................................... 5-19
ColdFire BDM Command Format............................................................ 5-20
Extension Words as Required............................................................... 5-21
Command Sequence Diagrams................................................................. 5-21
Command Set Descriptions ...................................................................... 5-23
Read A/D Register (RAREG/RDREG) ..................................................... 5-24
Write A/D Register (WAREG/WDREG)................................................... 5-25
Read Memory Location (READ)............................................................ 5-26
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CONTENTS
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Paragraph
Number
5.5.3.3.4
5.5.3.3.5
5.5.3.3.6
5.5.3.3.7
5.5.3.3.8
5.5.3.3.9
5.5.3.3.10
5.5.3.3.11
5.5.3.3.12
5.5.3.3.13
5.6
5.6.1
5.6.1.1
5.6.2
5.7
5.8
5.8.1
5.8.2
Title
Page
Number
Write Memory Location (WRITE) .........................................................
Dump Memory Block (DUMP) ..............................................................
Fill Memory Block (FILL) .....................................................................
Resume Execution (GO)........................................................................
No Operation (NOP) ..............................................................................
Synchronize PC to the PST/DDATA Lines (SYNC_PC) .......................
Read Control Register (RCREG) ............................................................
Write Control Register (WCREG) ..........................................................
Read Debug Module Register (RDMREG) .............................................
Write Debug Module Register (WDMREG) ...........................................
Real-Time Debug Support ................................................................................
Theory of Operation......................................................................................
Emulator Mode .........................................................................................
Concurrent BDM and Processor Operation ..................................................
Motorola-Recommended BDM Pinout.............................................................
Processor Status, DDATA Definition...............................................................
User Instruction Set ......................................................................................
Supervisor Instruction Set.............................................................................
5-27
5-29
5-31
5-33
5-34
5-35
5-36
5-37
5-38
5-39
5-39
5-40
5-41
5-41
5-42
5-42
5-43
5-46
Part II
System Integration Module (SIM)
Chapter 6
SIM Overview
6.1
6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
6.2.8
6.2.9
6.2.10
6.2.10.1
6.2.10.1.1
6.2.10.1.2
Features ............................................................................................................... 6-1
Programming Model ........................................................................................... 6-3
SIM Register Memory Map............................................................................ 6-3
Module Base Address Register (MBAR) ....................................................... 6-4
Reset Status Register (RSR) ........................................................................... 6-5
Software Watchdog Timer.............................................................................. 6-6
System Protection Control Register (SYPCR) ............................................... 6-8
Software Watchdog Interrupt Vector Register (SWIVR)............................... 6-9
Software Watchdog Service Register (SWSR)............................................... 6-9
PLL Clock Control for CPU STOP Instruction ............................................ 6-10
Pin Assignment Register (PAR) ................................................................... 6-10
Bus Arbitration Control ................................................................................ 6-11
Default Bus Master Park Register (MPARK) .......................................... 6-11
Arbitration for Internally Generated Transfers (MPARK[PARK])...... 6-12
Arbitration between Internal and External Masters
for Accessing Internal Resources ......................................................... 6-14
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CONTENTS
Paragraph
Number
Title
Page
Number
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Chapter 7
Phase-Locked Loop (PLL)
7.1
7.1.1
7.2
7.2.1
7.2.2
7.2.3
7.2.4
7.3
7.4
7.4.1
7.4.2
7.5
Overview.............................................................................................................
PLL:PCLK Ratios...........................................................................................
PLL Operation ....................................................................................................
Reset/Initialization ..........................................................................................
Normal Mode..................................................................................................
Reduced-Power Mode.....................................................................................
PLL Control Register (PLLCR)......................................................................
PLL Port List ......................................................................................................
Timing Relationships ..........................................................................................
PCLK, PSTCLK, and BCLKO .......................................................................
RSTI Timing ...................................................................................................
PLL Power Supply Filter Circuit ........................................................................
7-1
7-2
7-2
7-2
7-2
7-2
7-3
7-3
7-4
7-4
7-5
7-6
Chapter 8
I2C Module
8.1
8.2
8.3
8.4
8.4.1
8.4.2
8.4.3
8.4.4
8.5
8.5.1
8.5.2
8.5.3
8.5.4
8.5.5
8.6
8.6.1
8.6.2
8.6.3
8.6.4
8.6.5
8.6.6
8.6.7
x
Overview............................................................................................................. 8-1
Interface Features................................................................................................ 8-1
I2C System Configuration................................................................................... 8-3
I2C Protocol ........................................................................................................ 8-3
Arbitration Procedure ..................................................................................... 8-4
Clock Synchronization.................................................................................... 8-5
Handshaking ................................................................................................... 8-5
Clock Stretching ............................................................................................. 8-5
Programming Model ........................................................................................... 8-6
I2C Address Register (IADR) ......................................................................... 8-6
I2C Frequency Divider Register (IFDR)......................................................... 8-7
I2C Control Register (I2CR) ........................................................................... 8-8
I2C Status Register (I2SR).............................................................................. 8-9
I2C Data I/O Register (I2DR) ....................................................................... 8-10
2C Programming Examples ............................................................................. 8-10
I
Initialization Sequence.................................................................................. 8-10
Generation of START................................................................................... 8-10
Post-Transfer Software Response................................................................. 8-11
Generation of STOP...................................................................................... 8-12
Generation of Repeated START................................................................... 8-12
Slave Mode ................................................................................................... 8-13
Arbitration Lost............................................................................................. 8-13
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CONTENTS
Paragraph
Number
Title
Page
Number
Chapter 9
Interrupt Controller
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9.1
9.2
9.2.1
9.2.2
9.2.3
9.2.4
Overview.............................................................................................................
Interrupt Controller Registers .............................................................................
Interrupt Control Registers (ICR0–ICR9) ......................................................
Autovector Register (AVR) ............................................................................
Interrupt Pending and Mask Registers (IPR and IMR)...................................
Interrupt Port Assignment Register (IRQPAR) ..............................................
9-1
9-2
9-3
9-5
9-6
9-7
Chapter 10
Chip-Select Module
10.1
10.2
10.3
10.3.1
10.3.1.1
10.3.1.2
10.4
10.4.1
10.4.1.1
10.4.1.2
10.4.1.3
10.4.1.4
Overview...........................................................................................................
Chip-Select Module Signals .............................................................................
Chip-Select Operation.......................................................................................
General Chip-Select Operation.....................................................................
8-, 16-, and 32-Bit Port Sizing..................................................................
Global Chip-Select Operation...................................................................
Chip-Select Registers........................................................................................
Chip-Select Module Registers ......................................................................
Chip-Select Address Registers (CSAR0–CSAR7)...................................
Chip-Select Mask Registers (CSMR0–CSMR7)......................................
Chip-Select Control Registers (CSCR0–CSCR7) ....................................
Code Example...........................................................................................
10-1
10-1
10-2
10-3
10-4
10-4
10-5
10-6
10-6
10-6
10-8
10-9
Chapter 11
Synchronous/Asynchronous DRAM Controller Module
11.1
11.1.1
11.1.2
11.2
11.2.1
11.3
11.3.1
11.3.2
11.3.2.1
11.3.2.2
11.3.2.3
11.3.3
11.3.3.1
Overview........................................................................................................... 11-1
Definitions .................................................................................................... 11-2
Block Diagram and Major Components ....................................................... 11-2
DRAM Controller Operation ............................................................................ 11-3
DRAM Controller Registers ......................................................................... 11-3
Asynchronous Operation .................................................................................. 11-4
DRAM Controller Signals in Asynchronous Mode...................................... 11-4
Asynchronous Register Set........................................................................... 11-4
DRAM Control Register (DCR) in Asynchronous Mode ........................ 11-4
DRAM Address and Control Registers (DACR0/DACR1) ..................... 11-5
DRAM Controller Mask Registers (DMR0/DMR1) ................................ 11-7
General Asynchronous Operation Guidelines .............................................. 11-8
Non-Page-Mode Operation..................................................................... 11-11
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CONTENTS
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Paragraph
Number
11.3.3.2
11.3.3.3
11.3.3.4
11.3.3.5
11.4
11.4.1
11.4.2
11.4.3
11.4.3.1
11.4.3.2
11.4.3.3
11.4.4
11.4.4.1
11.4.4.2
11.4.4.3
11.4.4.4
11.4.4.5
11.4.4.6
11.4.5
11.4.5.1
11.5
11.5.1
11.5.2
11.5.3
11.5.4
11.5.5
11.5.6
Title
Page
Number
Burst Page-Mode Operation ................................................................... 11-12
Continuous Page Mode........................................................................... 11-13
Extended Data Out (EDO) Operation..................................................... 11-15
Refresh Operation ................................................................................... 11-16
Synchronous Operation................................................................................... 11-16
DRAM Controller Signals in Synchronous Mode...................................... 11-17
Using Edge Select (EDGESEL) ................................................................. 11-18
Synchronous Register Set ........................................................................... 11-19
DRAM Control Register (DCR) in Synchronous Mode.......................... 11-19
DRAM Address and Control Registers (DACR0/DACR1)
in Synchronous Mode ......................................................................... 11-20
DRAM Controller Mask Registers (DMR0/DMR1) .............................. 11-22
General Synchronous Operation Guidelines............................................... 11-23
Address Multiplexing ............................................................................. 11-23
Interfacing Example................................................................................ 11-27
Burst Page Mode..................................................................................... 11-27
Continuous Page Mode........................................................................... 11-29
Auto-Refresh Operation.......................................................................... 11-31
Self-Refresh Operation ........................................................................... 11-32
Initialization Sequence................................................................................ 11-33
Mode Register Settings........................................................................... 11-33
SDRAM Example ........................................................................................... 11-34
SDRAM Interface Configuration................................................................ 11-35
DCR Initialization....................................................................................... 11-35
DACR Initialization.................................................................................... 11-35
DMR Initialization...................................................................................... 11-37
Mode Register Initialization ....................................................................... 11-38
Initialization Code....................................................................................... 11-39
Part III
Peripheral Module
Chapter 12
DMA Controller Module
12.1
12.1.1
12.2
12.3
12.4
12.4.1
12.4.2
xii
Overview...........................................................................................................
DMA Module Features .................................................................................
DMA Signal Description ..................................................................................
DMA Transfer Overview..................................................................................
DMA Controller Module Programming Model................................................
Source Address Registers (SAR0–SAR3) ....................................................
Destination Address Registers (DAR0–DAR3) ...........................................
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Paragraph
Number
12.4.3
12.4.4
12.4.5
12.4.6
12.5
12.5.1
12.5.2
12.5.2.1
12.5.2.2
12.5.3
12.5.3.1
12.5.3.2
12.5.4
12.5.4.1
12.5.4.2
12.5.4.3
12.5.5
Title
Page
Number
Byte Count Registers (BCR0–BCR3)........................................................... 12-7
DMA Control Registers (DCR0–DCR3)...................................................... 12-8
DMA Status Registers (DSR0–DSR3) ....................................................... 12-10
DMA Interrupt Vector Registers (DIVR0–DIVR3) ................................... 12-11
DMA Controller Module Functional Description........................................... 12-11
Transfer Requests (Cycle-Steal and Continuous Modes) ........................... 12-12
Data Transfer Modes .................................................................................. 12-12
Dual-Address Transfers .......................................................................... 12-12
Single-Address Transfers........................................................................ 12-13
Channel Initialization and Startup .............................................................. 12-13
Channel Prioritization ............................................................................. 12-13
Programming the DMA Controller Module ........................................... 12-13
Data Transfer .............................................................................................. 12-14
External Request and Acknowledge Operation ...................................... 12-14
Auto-Alignment...................................................................................... 12-17
Bandwidth Control.................................................................................. 12-18
Termination................................................................................................. 12-18
Chapter 13
Timer Module
13.1
13.1.1
13.2
13.3
13.3.1
13.3.2
13.3.3
13.3.4
13.3.5
13.4
13.5
Overview...........................................................................................................
Key Features .................................................................................................
General-Purpose Timer Units ...........................................................................
General-Purpose Timer Programming Model ..................................................
Timer Mode Registers (TMR0/TMR1) ........................................................
Timer Reference Registers (TRR0/TRR1) ...................................................
Timer Capture Registers (TCR0/TCR1).......................................................
Timer Counters (TCN0/TCN1) ....................................................................
Timer Event Registers (TER0/TER1)...........................................................
Code Example...................................................................................................
Calculating Time-Out Values ...........................................................................
13-1
13-2
13-2
13-2
13-3
13-4
13-4
13-5
13-5
13-6
13-7
Chapter 14
UART Modules
14.1
14.2
14.3
14.3.1
14.3.2
14.3.3
Overview...........................................................................................................
Serial Module Overview ...................................................................................
Register Descriptions ........................................................................................
UART Mode Registers 1 (UMR1n)..............................................................
UART Mode Register 2 (UMR2n) ...............................................................
UART Status Registers (USRn) ...................................................................
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14-2
14-4
14-6
14-7
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Paragraph
Number
14.3.4
14.3.5
14.3.6
14.3.7
14.3.8
14.3.9
14.3.10
14.3.11
14.3.12
14.3.13
14.3.14
14.4
14.5
14.5.1
14.5.1.1
14.5.1.2
14.5.1.2.1
14.5.1.2.2
14.5.2
14.5.2.1
14.5.2.2
14.5.2.3
14.5.3
14.5.3.1
14.5.3.2
14.5.3.3
14.5.4
14.5.5
14.5.5.1
14.5.5.2
14.5.5.3
14.5.6
14.5.6.1
Title
Page
Number
UART Clock-Select Registers (UCSRn)...................................................... 14-8
UART Command Registers (UCRn) ............................................................ 14-9
UART Receiver Buffers (URBn) ............................................................... 14-11
UART Transmitter Buffers (UTBn) ........................................................... 14-11
UART Input Port Change Registers (UIPCRn).......................................... 14-12
UART Auxiliary Control Register (UACRn)............................................. 14-12
UART Interrupt Status/Mask Registers (UISRn/UIMRn).......................... 14-13
UART Divider Upper/Lower Registers (UDUn/UDLn) ............................ 14-14
UART Interrupt Vector Register (UIVRn)................................................. 14-15
UART Input Port Register (UIPn) .............................................................. 14-15
UART Output Port Command Registers (UOP1n/UOP0n) ....................... 14-15
UART Module Signal Definitions .................................................................. 14-16
Operation......................................................................................................... 14-18
Transmitter/Receiver Clock Source............................................................ 14-18
Programmable Divider............................................................................ 14-18
Calculating Baud Rates........................................................................... 14-19
BCLKO Baud Rates ........................................................................... 14-19
External Clock .................................................................................... 14-19
Transmitter and Receiver Operating Modes............................................... 14-19
Transmitting ........................................................................................... 14-21
Receiver .................................................................................................. 14-22
FIFO Stack ............................................................................................. 14-24
Looping Modes ........................................................................................... 14-25
Automatic Echo Mode ............................................................................ 14-25
Local Loop-Back Mode .......................................................................... 14-25
Remote Loop-Back Mode....................................................................... 14-26
Multidrop Mode.......................................................................................... 14-26
Bus Operation ............................................................................................. 14-28
Read Cycles ............................................................................................ 14-28
Write Cycles ........................................................................................... 14-28
Interrupt Acknowledge Cycles ............................................................... 14-28
Programming .............................................................................................. 14-28
UART Module Initialization Sequence .................................................. 14-29
Chapter 15
Parallel Port (General-Purpose I/O)
15.1
15.1.1
15.1.2
15.1.3
15.1.4
xiv
Parallel Port Operation......................................................................................
Pin Assignment Register (PAR) ...................................................................
Port A Data Direction Register (PADDR)....................................................
Port A Data Register (PADAT) ....................................................................
Code Example...............................................................................................
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Number
Title
Page
Number
Part IV
Hardware Interface
Freescale Semiconductor, Inc...
Chapter 16
Mechanical Data
16.1
16.2
16.3
16.4
Package .............................................................................................................
Pinout ................................................................................................................
Mechanical Diagram.........................................................................................
Case Drawing....................................................................................................
16-1
16-1
16-8
16-9
Chapter 17
Signal Descriptions
17.1
17.2
17.2.1
17.2.1.1
17.2.1.2
17.2.2
17.2.3
17.2.4
17.2.5
17.2.6
17.2.7
17.2.8
17.2.9
17.2.10
17.3
17.3.1
17.4
17.4.1
17.4.2
17.4.3
17.5
17.5.1
17.5.2
17.5.3
17.5.4
17.5.5
17.5.5.1
17.5.5.2
Overview........................................................................................................... 17-1
MCF5307 Bus Signals ...................................................................................... 17-7
Address Bus .................................................................................................. 17-7
Address Bus (A[23:0]).............................................................................. 17-7
Address Bus (A[31:24]/PP[15:8]) ............................................................ 17-7
Data Bus (D[31:0]) ....................................................................................... 17-8
Read/Write (R/W)......................................................................................... 17-8
Size (SIZ[1:0]) .............................................................................................. 17-8
Transfer Start (TS) ........................................................................................ 17-9
Address Strobe (AS) ..................................................................................... 17-9
Transfer Acknowledge (TA) ......................................................................... 17-9
Transfer In Progress (TIP/PP7)................................................................... 17-10
Transfer Type (TT[1:0]/PP[1:0]) ................................................................ 17-10
Transfer Modifier (TM[2:0]/PP[4:2])......................................................... 17-10
Interrupt Control Signals................................................................................. 17-12
Interrupt Request (IRQ1/IRQ2, IRQ3/IRQ6, IRQ5/IRQ4, and IRQ7)....... 17-12
Bus Arbitration Signals................................................................................... 17-12
Bus Request (BR) ....................................................................................... 17-12
Bus Grant (BG).......................................................................................... 17-12
Bus Driven (BD)......................................................................................... 17-13
Clock and Reset Signals.................................................................................. 17-13
Reset In (RSTI)........................................................................................... 17-13
Clock Input (CLKIN).................................................................................. 17-13
Bus Clock Output (BCLKO) ...................................................................... 17-13
Reset Out (RSTO)....................................................................................... 17-13
Data/Configuration Pins (D[7:0]) ............................................................... 17-13
D[7:5Boot Chip-Select (CS0) Configuration ......................................... 17-14
D7—Auto Acknowledge Configuration (AA_CONFIG) ...................... 17-14
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Number
17.5.5.3
17.5.6
17.5.7
17.5.8
17.6
17.6.1
17.6.2
17.6.3
17.7
17.7.1
17.7.2
17.7.3
17.7.4
17.7.5
17.7.6
17.7.7
17.8
17.8.1
17.9
17.9.1
17.9.2
17.9.3
17.9.4
17.10
17.10.1
17.10.2
17.11
17.12
17.12.1
17.12.2
17.13
17.13.1
17.13.2
17.13.3
17.13.4
17.13.5
17.14
17.14.1
17.14.2
17.14.3
17.14.4
17.14.5
xvi
Title
Page
Number
D[6:5]—Port Size Configuration (PS_CONFIG[1:0]) ........................... 17-14
D4—Address Configuration (ADDR_CONFIG) ....................................... 17-14
D[3:2]—Frequency Control PLL (FREQ[1:0] ..........................................) 17-15
D[1:0]—Divide Control PCLK to BCLKO (DIVIDE[1:0])....................... 17-15
Chip-Select Module Signals ........................................................................... 17-15
Chip-Select (CS[7:0]) ................................................................................. 17-16
Byte Enables/Byte Write Enables (BE[3:0]/BWE[3:0]) ............................ 17-16
Output Enable (OE) .................................................................................... 17-16
DRAM Controller Signals .............................................................................. 17-16
Row Address Strobes (RAS[1:0])............................................................... 17-16
Column Address Strobes (CAS[3:0]) ......................................................... 17-16
DRAM Write (DRAMW)........................................................................... 17-17
Synchronous DRAM Column Address Strobe (SCAS) ............................. 17-17
Synchronous DRAM Row Address Strobe (SRAS)................................... 17-17
Synchronous DRAM Clock Enable (SCKE) .............................................. 17-17
Synchronous Edge Select (EDGESEL) ...................................................... 17-17
DMA Controller Module Signals.................................................................... 17-17
DMA Request (DREQ[1:0]/PP[6:5]).......................................................... 17-18
Serial Module Signals ..................................................................................... 17-18
Transmitter Serial Data Output (TxD)........................................................ 17-18
Receiver Serial Data Input (RxD)............................................................... 17-18
Clear to Send (CTS).................................................................................... 17-18
Request to Send (RTS) ............................................................................... 17-18
Timer Module Signals..................................................................................... 17-18
Timer Inputs (TIN[1:0]).............................................................................. 17-19
Timer Outputs (TOUT1, TOUT0) .............................................................. 17-19
Parallel I/O Port (PP[15:0]) ............................................................................ 17-19
I2C Module Signals ........................................................................................ 17-19
I2C Serial Clock (SCL)............................................................................... 17-19
I2C Serial Data (SDA)................................................................................ 17-19
Debug and Test Signals .................................................................................. 17-20
Test Mode (MTMOD[3:0]) ........................................................................ 17-20
High Impedance (HIZ)................................................................................ 17-20
Processor Clock Output (PSTCLK)............................................................ 17-20
Debug Data (DDATA[3:0])........................................................................ 17-20
Processor Status (PST[3:0])........................................................................ 17-20
Debug Module/JTAG Signals......................................................................... 17-21
Test Reset/Development Serial Clock (TRST/DSCLK) ............................ 17-21
Test Mode Select/Breakpoint (TMS/BKPT) .............................................. 17-22
Test Data Input/Development Serial Input (TDI/DSI) ............................... 17-22
Test Data Output/Development Serial Output (TDO/DSO)....................... 17-22
Test Clock (TCK) ....................................................................................... 17-23
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Chapter 18
Bus Operation
18.1
18.2
18.3
18.4
18.4.1
18.4.2
18.4.3
18.4.4
18.4.5
18.4.6
18.4.7
18.4.7.1
18.4.7.2
18.4.7.3
18.4.7.4
18.5
18.6
18.7
18.7.1
18.7.2
18.8
18.8.1
18.9
18.9.1
18.9.2
18.10
18.10.1
18.10.2
Features ............................................................................................................. 18-1
Bus and Control Signals ................................................................................... 18-1
Bus Characteristics............................................................................................ 18-2
Data Transfer Operation ................................................................................... 18-3
Bus Cycle Execution..................................................................................... 18-4
Data Transfer Cycle States ........................................................................... 18-5
Read Cycle.................................................................................................... 18-7
Write Cycle ................................................................................................... 18-8
Fast-Termination Cycles............................................................................... 18-9
Back-to-Back Bus Cycles ........................................................................... 18-10
Burst Cycles................................................................................................ 18-11
Line Transfers ......................................................................................... 18-12
Line Read Bus Cycles............................................................................. 18-12
Line Write Bus Cycles............................................................................ 18-14
Transfers Using Mixed Port Sizes .......................................................... 18-15
Misaligned Operands ...................................................................................... 18-16
Bus Errors ....................................................................................................... 18-17
Interrupt Exceptions........................................................................................ 18-17
Level 7 Interrupts........................................................................................ 18-18
Interrupt-Acknowledge Cycle..................................................................... 18-19
Bus Arbitration................................................................................................ 18-20
Bus Arbitration Signals............................................................................... 18-21
General Operation of External Master Transfers............................................ 18-21
Two-Device Bus Arbitration Protocol (Two-Wire Mode) ......................... 18-25
Multiple External Bus Device Arbitration Protocol (Three-Wire Mode)... 18-29
Reset Operation............................................................................................... 18-33
Master Reset ............................................................................................... 18-34
Software Watchdog Reset........................................................................... 18-35
Chapter 19
IEEE 1149.1 Test Access Port (JTAG)
19.1
19.2
19.3
19.4
19.4.1
19.4.2
19.4.3
Overview...........................................................................................................
JTAG Signal Descriptions ...............................................................................
TAP Controller..................................................................................................
JTAG Register Descriptions .............................................................................
JTAG Instruction Shift Register ..................................................................
IDCODE Register .........................................................................................
JTAG Boundary-Scan Register ....................................................................
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19-2
19-3
19-4
19-5
19-6
19-7
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CONTENTS
Paragraph
Number
19.4.4
19.5
19.6
19.7
Title
Page
Number
JTAG Bypass Register................................................................................
Restrictions .....................................................................................................
Disabling IEEE Standard 1149.1 Operation ...................................................
Obtaining the IEEE Standard 1149.1..............................................................
19-10
19-10
19-11
19-12
Freescale Semiconductor, Inc...
Chapter 20
Electrical Specifications
20.1
20.2
20.3
20.4
20.5
20.6
20.7
20.8
20.9
20.10
20.11
xviii
General Parameters ........................................................................................... 20-1
Clock Timing Specifications............................................................................. 20-2
Input/Output AC Timing Specifications........................................................... 20-3
Reset Timing Specifications ........................................................................... 20-12
Debug AC Timing Specifications................................................................... 20-12
Timer Module AC Timing Specifications ...................................................... 20-14
I2C Input/Output Timing Specifications......................................................... 20-15
UART Module AC Timing Specifications ..................................................... 20-16
Parallel Port (General-Purpose I/O) Timing Specifications ........................... 20-18
DMA Timing Specifications........................................................................... 20-19
IEEE 1149.1 (JTAG) AC Timing Specifications ........................................... 20-20
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Figure
Number
1-1
1-2
1-3
1-4
2-1
2-2
2-3
2-5
2-6
2-7
2-8
2-9
2-10
3-1
3-2
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
Title
Page
Number
MCF5307 Block Diagram............................................................................................. 1-2
UART Module Block Diagram..................................................................................... 1-9
PLL Module ................................................................................................................ 1-12
ColdFire MCF5307 Programming Model .................................................................. 1-13
ColdFire Enhanced Pipeline ....................................................................................... 2-23
ColdFire Multiply-Accumulate Functionality Diagram ............................................. 2-25
ColdFire Programming Model.................................................................................... 2-27
Status Register (SR).................................................................................................... 2-30
Vector Base Register (VBR)....................................................................................... 2-30
Organization of Integer Data Formats in Data Registers............................................ 2-32
Organization of Integer Data Formats in Address Registers ...................................... 2-32
Memory Operand Addressing..................................................................................... 2-33
Exception Stack Frame Form...................................................................................... 2-49
ColdFire MAC Multiplication and Accumulation........................................................ 3-2
MAC Programming Model ........................................................................................... 3-2
SRAM Base Address Register (RAMBAR) ................................................................. 4-3
Unified Cache Organization ......................................................................................... 4-7
Cache Organization and Line Format ........................................................................... 4-8
Cache—A: at Reset, B: after Invalidation, C and D: Loading Pattern ....................... 4-10
Caching Operation ...................................................................................................... 4-11
Write-Miss in Copyback Mode................................................................................... 4-16
Cache Locking ............................................................................................................ 4-20
Cache Control Register (CACR) ................................................................................ 4-21
Access Control Register Format (ACRn) ................................................................... 4-23
An Format .................................................................................................................. 4-24
Cache Line State Diagram—Copyback Mode............................................................ 4-26
Cache Line State Diagram—Write-Through Mode.................................................... 4-26
Processor/Debug Module Interface............................................................................... 5-1
PSTCLK Timing........................................................................................................... 5-3
Example JMP Instruction Output on PST/DDATA...................................................... 5-5
Debug Programming Model ......................................................................................... 5-6
Address Attribute Trigger Register (AATR) ................................................................ 5-7
Address Breakpoint Registers (ABLR, ABHR) ........................................................... 5-9
BDM Address Attribute Register (BAAR)................................................................... 5-9
Configuration/Status Register (CSR).......................................................................... 5-10
Data Breakpoint/Mask Registers (DBR and DBMR)................................................. 5-12
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ILLUSTRATIONS
Figure
Page
Title
Number
Number
5-10
Program Counter Breakpoint Register (PBR)............................................................. 5-14
5-11
Program Counter Breakpoint Mask Register (PBMR) ............................................... 5-14
5-12
Trigger Definition Register (TDR) ............................................................................. 5-15
5-13
BDM Serial Interface Timing ..................................................................................... 5-18
5-14
Receive BDM Packet.................................................................................................. 5-19
5-15
Transmit BDM Packet ................................................................................................ 5-19
5-16
BDM Command Format ............................................................................................. 5-21
5-17
Command Sequence Diagram..................................................................................... 5-22
RAREG/RDREG Command Sequence............................................................................ 5-24
5-19
RAREG/RDREG Command Format ............................................................................... 5-24
5-18
WAREG/WDREG Command Sequence .......................................................................... 5-25
5-21
WAREG/WDREG Command Format.............................................................................. 5-25
5-20
READ Command Sequence.......................................................................................... 5-26
5-23
READ Command/Result Formats................................................................................. 5-26
5-22
WRITE Command Format ............................................................................................ 5-27
5-24
WRITE Command Sequence ........................................................................................ 5-28
5-25
DUMP Command/Result Formats ................................................................................ 5-29
5-26
DUMP Command Sequence ......................................................................................... 5-30
5-27
FILL Command Format................................................................................................ 5-31
5-28
FILL Command Sequence............................................................................................ 5-32
5-29
GO Command Sequence.............................................................................................. 5-33
5-31
GO Command Format.................................................................................................. 5-33
5-30
NOP Command Sequence ............................................................................................ 5-34
5-33
NOP Command Format................................................................................................ 5-34
5-32
SYNC_PC Command Sequence .................................................................................... 5-35
5-35
SYNC_PC Command Format........................................................................................ 5-35
5-34
RCREG Command Sequence........................................................................................ 5-36
5-37
RCREG Command/Result Formats............................................................................... 5-36
5-36
WCREG Command Sequence ....................................................................................... 5-37
5-39
WCREG Command/Result Formats.............................................................................. 5-37
5-38
RDMREG Command Sequence..................................................................................... 5-38
5-41
RDMREG bdm Command/Result Formats.................................................................... 5-38
5-40
WDMREG Command Sequence .................................................................................... 5-39
5-43
WDMREG BDM Command Format.............................................................................. 5-39
5-42
5-44
Recommended BDM Connector................................................................................. 5-42
6-1
SIM Block Diagram...................................................................................................... 6-1
6-2
Module Base Address Register (MBAR) ..................................................................... 6-4
6-3
Reset Status Register (RSR) ......................................................................................... 6-5
6-4
MCF5307 Embedded System Recovery from Unterminated Access........................... 6-7
6-5
System Protection Control Register (SYPCR) ............................................................. 6-8
6-6
Software Watchdog Interrupt Vector Register (SWIVR)............................................. 6-9
6-7
Software Watchdog Service Register (SWSR)............................................................. 6-9
6-8
Pin Assignment Register (PAR) ................................................................................. 6-10
xx
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Figure
Number
6-9
6-10
6-11
6-12
6-13
7-1
7-2
7-3
7-4
7-5
8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
8-9
8-10
9-1
9-2
9-3
9-4
9-5
10-1
10-2
10-3
10-4
11-1
11-2
11-3
11-4
11-5
11-6
11-7
11-8
11-9
11-10
11-11
11-12
11-13
11-14
Title
Page
Number
Default Bus Master Register (MPARK) ..................................................................... 6-11
Round Robin Arbitration (PARK = 00)...................................................................... 6-12
Park on Master Core Priority (PARK = 01) ............................................................... 6-13
Park on DMA Module Priority (PARK = 10)............................................................. 6-13
Park on Current Master Priority (PARK = 01) ........................................................... 6-14
PLL Module Block Diagram ........................................................................................ 7-1
PLL Control Register (PLLCR).................................................................................... 7-3
CLKIN, PCLK, PSTCLK, and BCLKO Timing .......................................................... 7-5
Reset and Initialization Timing..................................................................................... 7-6
PLL Power Supply Filter Circuit .................................................................................. 7-6
I2C Module Block Diagram .......................................................................................... 8-2
I2C Standard Communication Protocol ........................................................................ 8-3
Repeated START .......................................................................................................... 8-4
Synchronized Clock SCL.............................................................................................. 8-5
I2C Address Register (IADR) ....................................................................................... 8-6
I2C Frequency Divider Register (IFDR)....................................................................... 8-7
I2C Control Register (I2CR) ......................................................................................... 8-8
I2CR Status Register (I2SR) ......................................................................................... 8-9
I2C Data I/O Register (I2DR) ..................................................................................... 8-10
Flow-Chart of Typical I2C Interrupt Routine ............................................................. 8-14
Interrupt Controller Block Diagram.............................................................................. 9-1
Interrupt Control Registers (ICR0–ICR9) .................................................................... 9-3
Autovector Register (AVR) .......................................................................................... 9-5
Interrupt Pending Register (IPR) and Interrupt Mask Register (IMR) ......................... 9-7
Interrupt Port Assignment Register (IRQPAR) ............................................................ 9-7
Connections for External Memory Port Sizes ............................................................ 10-4
Chip Select Address Registers (CSAR0–CSAR7) ..................................................... 10-6
Chip Select Mask Registers (CSMRn) ....................................................................... 10-7
Chip-Select Control Registers (CSCR0–CSCR7) ...................................................... 10-8
Asynchronous/Synchronous DRAM Controller Block Diagram ............................... 11-2
DRAM Control Register (DCR) (Asynchronous Mode) ............................................ 11-5
DRAM Address and Control Registers (DACR0/DACR1)........................................ 11-6
DRAM Controller Mask Registers (DMR0 and DMR1)............................................ 11-7
Basic Non-Page-Mode Operation RCD = 0, RNCN = 1 (4-4-4-4) .......................... 11-11
Basic Non-Page-Mode Operation RCD = 1, RNCN = 0 (5-5-5-5) .......................... 11-12
Burst Page-Mode Read Operation (4-3-3-3)............................................................. 11-13
Burst Page-Mode Write Operation (4-3-3-3)............................................................ 11-13
Continuous Page-Mode Operation............................................................................ 11-14
Write Hit in Continuous Page Mode......................................................................... 11-15
EDO Read Operation (3-2-2-2) ................................................................................ 11-15
DRAM Access Delayed by Refresh ......................................................................... 11-16
MCF5307 SDRAM Interface.................................................................................... 11-18
Using EDGESEL to Change Signal Timing............................................................. 11-19
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Figure
Page
Title
Number
Number
11-15 DRAM Control Register (DCR) (Synchronous Mode) ............................................ 11-19
11-16 DACR0 and DACR1 Registers (Synchronous Mode).............................................. 11-20
11-17 DRAM Controller Mask Registers (DMR0 and DMR1).......................................... 11-22
11-18 Burst Read SDRAM Access ..................................................................................... 11-28
11-19 Burst Write SDRAM Access .................................................................................... 11-29
11-20 Synchronous, Continuous Page-Mode Access—Consecutive Reads....................... 11-30
11-21 Synchronous, Continuous Page-Mode Access—Read after Write........................... 11-31
11-22 Auto-Refresh Operation............................................................................................ 11-32
11-23 Self-Refresh Operation ............................................................................................. 11-32
11-24 Mode Register Set (mrs) Command ......................................................................... 11-34
11-25 Initialization Values for DCR ................................................................................... 11-35
11-26 SDRAM Configuration............................................................................................. 11-36
11-27 DACR Register Configuration.................................................................................. 11-36
11-28 DMR0 Register ......................................................................................................... 11-37
11-29 Mode Register Mapping to MCF5307 A[31:0] ........................................................ 11-38
12-1
DMA Signal Diagram ................................................................................................. 12-1
12-2
Dual-Address Transfer................................................................................................ 12-3
12-3
Single-Address Transfers............................................................................................ 12-4
12-4
Source Address Registers (SARn) .............................................................................. 12-6
12-5
Destination Address Registers (DARn) ...................................................................... 12-7
12-6
Byte Count Registers (BCRn)—BCR24BIT = 1 ........................................................ 12-7
12-7
BCRn—BCR24BIT = 0.............................................................................................. 12-8
12-8
DMA Control Registers (DCRn) ............................................................................... 12-8
12-9
DMA Status Registers (DSRn) ................................................................................ 12-10
12-10 DMA Interrupt Vector Registers (DIVRn) ............................................................... 12-11
12-11 DREQ Timing Constraints, Dual-Address DMA Transfer....................................... 12-15
12-12 Dual-Address, Peripheral-to-SDRAM, Lower-Priority DMA Transfer ................... 12-16
12-13 Single-Address DMA Transfer ................................................................................. 12-17
13-1
Timer Block Diagram ................................................................................................. 13-1
13-2
Timer Mode Registers (TMR0/TMR1) ...................................................................... 13-3
13-3
Timer Reference Registers (TRR0/TRR1) ................................................................. 13-4
13-4
Timer Capture Register (TCR0/TCR1) ...................................................................... 13-5
13-5
Timer Counters (TCN0/TCN1)................................................................................... 13-5
13-6
Timer Event Registers (TER0/TER1)......................................................................... 13-5
14-1
Simplified Block Diagram .......................................................................................... 14-1
14-2
UART Mode Registers 1 (UMR1n)............................................................................ 14-5
14-3
UART Mode Register 2 (UMR2n) ............................................................................. 14-6
14-4
UART Status Register (USRn) ................................................................................... 14-7
14-5
UART Clock-Select Register (UCSRn)...................................................................... 14-8
14-6
UART Command Register (UCRn)............................................................................ 14-9
14-7
UART Receiver Buffer (URB0) ............................................................................... 14-11
14-8
UART Transmitter Buffer (UTB0)........................................................................... 14-12
14-9
UART Input Port Change Register (UIPCRn).......................................................... 14-12
xxii
MCF5307 User’s Manual
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ILLUSTRATIONS
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Figure
Number
14-10
14-11
14-12
14-13
14-14
14-15
14-17
14-16
14-18
14-19
14-20
14-21
14-22
14-23
14-24
14-25
14-26
14-27
15-1
15-2
15-3
16-1
16-2
16-3
17-1
18-1
18-2
18-3
18-4
18-5
18-6
18-7
18-8
18-9
18-10
18-11
18-12
18-13
18-14
18-15
18-16
18-17
18-18
Title
Page
Number
UART Auxiliary Control Register (UACRn) ........................................................... 14-13
UART Interrupt Status/Mask Registers (UISRn/UIMRn)........................................ 14-13
UART Divider Upper Register (UDUn)................................................................... 14-14
UART Divider Lower Register (UDLn)................................................................... 14-14
UART Interrupt Vector Register (UIVRn) ............................................................... 14-15
UART Input Port Register (UIPn) ............................................................................ 14-15
UART Block Diagram Showing External and Internal Interface Signals ................ 14-16
UART Output Port Command Register (UOP1/UOP0) ........................................... 14-16
UART/RS-232 Interface ........................................................................................... 14-17
Clocking Source Diagram......................................................................................... 14-18
Transmitter and Receiver Functional Diagram......................................................... 14-20
Transmitter Timing Diagram .................................................................................... 14-22
Receiver Timing........................................................................................................ 14-23
Automatic Echo ........................................................................................................ 14-25
Local Loop-Back ...................................................................................................... 14-26
Remote Loop-Back ................................................................................................... 14-26
Multidrop Mode Timing Diagram ............................................................................ 14-27
UART Mode Programming Flowchart ..................................................................... 14-30
Parallel Port Pin Assignment Register (PAR) ............................................................ 15-1
Port A Data Direction Register (PADDR).................................................................. 15-2
Port A Data Register (PADAT) .................................................................................. 15-3
Mechanical Diagram................................................................................................... 16-9
MCF5307 Case Drawing (General View) ................................................................ 16-10
Case Drawing (Details)............................................................................................. 16-11
MCF5307 Block Diagram with Signal Interfaces ...................................................... 17-2
Signal Relationship to BCLKO for Non-DRAM Access ........................................... 18-2
Connections for External Memory Port Sizes ............................................................ 18-4
Chip-Select Module Output Timing Diagram ............................................................ 18-4
Data Transfer State Transition Diagram ..................................................................... 18-6
Read Cycle Flowchart................................................................................................. 18-7
Basic Read Bus Cycle................................................................................................. 18-8
Write Cycle Flowchart................................................................................................ 18-9
Basic Write Bus Cycle ................................................................................................ 18-9
Read Cycle with Fast Termination ........................................................................... 18-10
Write Cycle with Fast Termination........................................................................... 18-10
Back-to-Back Bus Cycles ......................................................................................... 18-11
Line Read Burst (2-1-1-1), External Termination .................................................... 18-12
Line Read Burst (2-1-1-1), Internal Termination ..................................................... 18-13
Line Read Burst (3-2-2-2), External Termination .................................................... 18-13
Line Read Burst-Inhibited, Fast, External Termination............................................ 18-14
Line Write Burst (2-1-1-1), Internal/External Termination...................................... 18-14
Line Write Burst (3-2-2-2) with One Wait State, Internal Termination ................... 18-15
Line Write Burst-Inhibited, Internal Termination .................................................... 18-15
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ILLUSTRATIONS
Figure
Page
Title
Number
Number
18-19 Longword Read from an 8-Bit Port, External Termination...................................... 18-16
18-20 Longword Read from an 8-Bit Port, Internal Termination ....................................... 18-16
18-21 Example of a Misaligned Longword Transfer (32-Bit Port) .................................... 18-17
18-22 Example of a Misaligned Word Transfer (32-Bit Port) ............................................ 18-17
18-23 Interrupt-Acknowledge Cycle Flowchart ................................................................. 18-20
18-24 Basic No-Wait-State External Master Access .......................................................... 18-22
18-25 External Master Burst Line Access to 32-Bit Port.................................................... 18-24
18-26 MCF5307 Two-Wire Mode Bus Arbitration Interface............................................. 18-25
18-27 Two-Wire Bus Arbitration with Bus Request Asserted............................................ 18-26
18-28 Two-Wire Implicit and Explicit Bus Mastership...................................................... 18-27
18-29 MCF5307 Two-Wire Bus Arbitration Protocol State Diagram................................ 18-28
18-30 Three-Wire Implicit and Explicit Bus Mastership.................................................... 18-30
18-31 Three-Wire Bus Arbitration...................................................................................... 18-31
18-32 Three-Wire Bus Arbitration Protocol State Diagram ............................................... 18-32
18-33 Master Reset Timing................................................................................................. 18-34
18-34 Software Watchdog Reset Timing ............................................................................ 18-36
19-1
JTAG Test Logic Block Diagram ............................................................................... 19-2
19-2
JTAG TAP Controller State Machine......................................................................... 19-4
19-4
Disabling JTAG in JTAG Mode ............................................................................... 19-11
19-5
Disabling JTAG in Debug Mode .............................................................................. 19-11
20-1
Clock Timing .............................................................................................................. 20-3
20-2
PSTCLK Timing......................................................................................................... 20-3
20-3
AC Timings—Normal Read and Write Bus Cycles ................................................... 20-5
20-4
SDRAM Read Cycle with EDGESEL Tied to Buffered BCLKO.............................. 20-6
20-5
SDRAM Write Cycle with EDGESEL Tied to Buffered BCLKO............................. 20-7
20-6
SDRAM Read Cycle with EDGESEL Tied High....................................................... 20-8
20-7
SDRAM Write Cycle with EDGESEL Tied High...................................................... 20-9
20-8
SDRAM Read Cycle with EDGESEL Tied Low ..................................................... 20-10
20-9
SDRAM Write Cycle with EDGESEL Tied Low .................................................... 20-11
20-10 AC Output Timing—High Impedance...................................................................... 20-11
20-11 Reset Timing............................................................................................................. 20-12
20-12 Real-Time Trace AC Timing .................................................................................... 20-13
20-13 BDM Serial Port AC Timing .................................................................................... 20-13
20-14 Timer Module AC Timing ........................................................................................ 20-14
20-15 I2C Input/Output Timings......................................................................................... 20-16
20-16 UART0/1 Module AC Timing—UART Mode......................................................... 20-17
20-17 General-Purpose I/O Timing..................................................................................... 20-18
20-18 DMA Timing ............................................................................................................ 20-19
20-19 IEEE 1149.1 (JTAG) AC Timing ............................................................................. 20-21
xxiv
MCF5307 User’s Manual
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TABLES
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Table
Number
1-1
1-2
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
2-16
2-17
2-18
2-19
2-20
2-21
3-1
3-2
3-3
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
5-1
Title
Page
Number
User-Level Registers................................................................................................... 1-14
Supervisor-Level Registers......................................................................................... 1-14
CCR Field Descriptions ............................................................................................. 2-28
MOVEC Register Map ............................................................................................... 2-29
Status Field Descriptions ............................................................................................ 2-30
Integer Data Formats................................................................................................... 2-31
ColdFire Effective Addressing Modes........................................................................ 2-34
Notational Conventions .............................................................................................. 2-34
User-Mode Instruction Set Summary ......................................................................... 2-37
Supervisor-Mode Instruction Set Summary................................................................ 2-40
Misaligned Operand References ................................................................................. 2-41
Move Byte and Word Execution Times...................................................................... 2-42
Move Long Execution Times...................................................................................... 2-42
MAC Move Execution Times..................................................................................... 2-43
One-Operand Instruction Execution Times ................................................................ 2-43
Two-Operand Instruction Execution Times................................................................ 2-44
Miscellaneous Instruction Execution Times............................................................... 2-45
General Branch Instruction Execution Times............................................................. 2-46
Bcc Instruction Execution Times................................................................................ 2-47
Exception Vector Assignments................................................................................... 2-48
Format Field Encoding ............................................................................................... 2-49
Fault Status Encodings................................................................................................ 2-50
MCF5307 Exceptions ................................................................................................. 2-50
MAC Instruction Summary........................................................................................... 3-4
Two-Operand MAC Instruction Execution Times ....................................................... 3-5
MAC Move Instruction Execution Times..................................................................... 3-6
RAMBAR Field Description ........................................................................................ 4-3
Examples of Typical RAMBAR Settings ..................................................................... 4-6
Valid and Modified Bit Settings ................................................................................... 4-8
CACR Field Descriptions ........................................................................................... 4-21
ACRn Field Descriptions............................................................................................ 4-23
Cache Line State Transitions ...................................................................................... 4-27
Cache Line State Transitions (Current State Invalid) ................................................. 4-28
Cache Line State Transitions (Current State Valid) ................................................... 4-28
Cache Line State Transitions (Current State Modified) ............................................. 4-29
Debug Module Signals.................................................................................................. 5-2
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TABLES
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Table
Number
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5-13
5-14
5-15
5-16
5-17
5-18
5-19
5-20
5-21
5-22
5-23
6-1
6-2
6-3
6-4
6-5
6-6
7-1
7-2
7-3
8-1
8-2
8-3
8-4
8-5
9-1
9-2
9-3
9-4
9-5
9-6
9-7
xxvi
Title
Page
Number
Processor Status Encoding............................................................................................ 5-4
BDM/Breakpoint Registers........................................................................................... 5-7
AATR Field Descriptions ............................................................................................. 5-8
ABLR Field Description ............................................................................................... 5-9
ABHR Field Description............................................................................................... 5-9
BAAR Field Descriptions ........................................................................................... 5-10
CSR Field Descriptions .............................................................................................. 5-11
DBR Field Descriptions.............................................................................................. 5-13
DBMR Field Descriptions .......................................................................................... 5-13
Access Size and Operand Data Location .................................................................... 5-13
PBR Field Descriptions .............................................................................................. 5-14
PBMR Field Descriptions ........................................................................................... 5-14
TDR Field Descriptions .............................................................................................. 5-15
Receive BDM Packet Field Description ..................................................................... 5-19
Transmit BDM Packet Field Description ................................................................... 5-19
BDM Command Summary ......................................................................................... 5-20
BDM Field Descriptions ............................................................................................. 5-21
Control Register Map.................................................................................................. 5-36
Definition of DRc Encoding—Read........................................................................... 5-38
DDATA[3:0]/CSR[BSTAT] Breakpoint Response.................................................... 5-40
PST/DDATA Specification for User-Mode Instructions............................................ 5-43
PST/DDATA Specification for Supervisor-Mode Instructions.................................. 5-46
SIM Registers .............................................................................................................. 6-3
MBAR Field Descriptions ............................................................................................ 6-5
RSR Field Descriptions ................................................................................................ 6-6
SYPCR Field Descriptions ........................................................................................... 6-8
PLLIPL Settings ......................................................................................................... 6-10
MPARK Field Descriptions........................................................................................ 6-11
PLLCR Field Descriptions............................................................................................ 7-3
PLL Module Input SIgnals............................................................................................ 7-3
PLL Module Output Signals ......................................................................................... 7-4
I2C Interface Memory Map........................................................................................... 8-6
I2C Address Register Field Descriptions ...................................................................... 8-6
IFDR Field Descriptions ............................................................................................... 8-7
I2CR Field Descriptions................................................................................................ 8-8
I2SR Field Descriptions ................................................................................................ 8-9
Interrupt Controller Registers ....................................................................................... 9-2
Interrupt Control Registers ........................................................................................... 9-2
ICRn Field Descriptions ............................................................................................... 9-3
Interrupt Priority Scheme.............................................................................................. 9-4
AVR Field Descriptions................................................................................................ 9-6
Autovector Register Bit Assignments........................................................................... 9-6
IPR and IMR Field Descriptions................................................................................... 9-7
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Table
Number
9-8
10-1
10-2
10-3
10-4
10-5
10-6
10-7
10-8
10-9
11-1
11-2
11-3
11-4
11-5
11-6
11-7
11-8
11-9
11-10
11-11
11-12
11-13
11-14
11-15
11-16
11-17
11-18
11-19
11-20
11-21
11-22
11-23
11-24
11-25
11-26
11-27
11-28
11-29
11-30
11-31
11-32
11-33
Title
Page
Number
IRQPAR Field Descriptions ......................................................................................... 9-8
Chip-Select Module Signals ....................................................................................... 10-1
Byte Enables/Byte Write Enable Signal Settings ....................................................... 10-2
Accesses by Matches in CSCRs and DACRs ............................................................. 10-3
D7/AA, Automatic Acknowledge of Boot CS0.......................................................... 10-4
D[6:5]/PS[1:0], Port Size of Boot CS0 ....................................................................... 10-4
Chip-Select Registers.................................................................................................. 10-5
CSARn Field Description ........................................................................................... 10-6
CSMRn Field Descriptions ......................................................................................... 10-7
CSCRn Field Descriptions.......................................................................................... 10-8
DRAM Controller Registers ....................................................................................... 11-3
SDRAM Signal Summary ......................................................................................... 11-4
DCR Field Descriptions (Asynchronous Mode)......................................................... 11-5
DACR0/DACR1 Field Description ............................................................................ 11-6
DMR0/DMR1 Field Descriptions............................................................................... 11-7
Generic Address Multiplexing Scheme ...................................................................... 11-8
DRAM Addressing for Byte-Wide Memories.......................................................... 11-10
DRAM Addressing for 16-Bit Wide Memories........................................................ 11-10
DRAM Addressing for 32-Bit Wide Memories........................................................ 11-11
SDRAM Commands ................................................................................................. 11-17
Synchronous DRAM Signal Connections ................................................................ 11-17
DCR Field Descriptions (Synchronous Mode) ......................................................... 11-19
DACR0/DACR1 Field Descriptions (Synchronous Mode)...................................... 11-21
DMR0/DMR1 Field Descriptions............................................................................. 11-23
MCF5307 to SDRAM Interface (8-Bit Port, 9-Column Address Lines).................. 11-24
MCF5307 to SDRAM Interface (8-Bit Port,10-Column Address Lines)................. 11-24
MCF5307 to SDRAM Interface (8-Bit Port,11-Column Address Lines)................. 11-24
MCF5307 to SDRAM Interface (8-Bit Port,12-Column Address Lines)................. 11-24
MCF5307 to SDRAM Interface (8-Bit Port,13-Column Address Lines)................. 11-25
MCF5307 to SDRAM Interface (16-Bit Port, 8-Column Address Lines)................ 11-25
MCF5307 to SDRAM Interface (16-Bit Port, 9-Column Address Lines)................ 11-25
MCF5307 to SDRAM Interface (16-Bit Port, 10-Column Address Lines).............. 11-25
MCF5307 to SDRAM Interface (16-Bit Port, 11-Column Address Lines).............. 11-25
MCF5307 to SDRAM Interface (16-Bit Port, 12-Column Address Lines).............. 11-26
MCF5307to SDRAM Interface (16-Bit Port, 13-Column-Address Lines) .............. 11-26
MCF5307 to SDRAM Interface (32-Bit Port, 8-Column Address Lines)................ 11-26
MCF5307 to SDRAM Interface (32-Bit Port, 9-Column Address Lines)................ 11-26
MCF5307 to SDRAM Interface (32-Bit Port, 10-Column Address Lines).............. 11-26
MCF5307 to SDRAM Interface (32-Bit Port, 11-Column Address Lines).............. 11-27
MCF5307 to SDRAM Interface (32-Bit Port, 12-Column Address Lines).............. 11-27
SDRAM Hardware Connections............................................................................... 11-27
SDRAM Example Specifications ............................................................................. 11-34
SDRAM Hardware Connections............................................................................... 11-35
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TABLES
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Table
Number
11-34
11-35
11-36
11-37
12-1
12-2
12-3
12-4
13-1
13-2
13-3
13-5
14-1
14-2
14-3
14-4
14-5
14-6
14-7
14-8
14-9
14-10
14-11
14-12
14-13
14-14
15-1
15-2
15-3
16-1
16-2
16-3
16-4
16-5
17-1
17-2
17-3
17-4
17-5
17-6
17-7
17-8
17-9
xxviii
Title
Page
Number
DCR Initialization Values......................................................................................... 11-35
DACR Initialization Values...................................................................................... 11-36
DMR0 Initialization Values...................................................................................... 11-37
Mode Register Initialization ..................................................................................... 11-38
DMA Signals .............................................................................................................. 12-2
Memory Map for DMA Controller Module Registers................................................ 12-5
DCRn Field Descriptions............................................................................................ 12-8
DSRn Field Descriptions .......................................................................................... 12-10
General-Purpose Timer Module Memory Map .......................................................... 13-3
TMRn Field Descriptions ........................................................................................... 13-4
TERn Field Descriptions............................................................................................. 13-6
Calculated Time-out Values (90-MHz Processor Clock) ........................................... 13-7
UART Module Programming Model.......................................................................... 14-3
UMR1n Field Descriptions ......................................................................................... 14-5
UMR2n Field Descriptions ......................................................................................... 14-6
USRn Field Descriptions ............................................................................................ 14-7
UCSRn Field Descriptions.......................................................................................... 14-9
UCRn Field Descriptions............................................................................................ 14-9
UIPCRn Field Descriptions ...................................................................................... 14-12
UACRn Field Descriptions ....................................................................................... 14-13
UISRn/UIMRn Field Descriptions ........................................................................... 14-14
UIVRn Field Descriptions ........................................................................................ 14-15
UIPn Field Descriptions............................................................................................ 14-15
UOP1/UOP0 Field Descriptions ............................................................................... 14-16
UART Module Signals ............................................................................................. 14-17
UART Module Initialization Sequence .................................................................... 14-29
Parallel Port Pin Descriptions ..................................................................................... 15-2
PADDR Field Description .......................................................................................... 15-2
Relationship between PADAT Register and Parallel Port Pin (PP) ........................... 15-3
Pins 1–52 (Left, Top-to-Bottom) ................................................................................ 16-1
Pins 53–104 (Bottom, Left-to-Right).......................................................................... 16-3
Pins 105–156 (Right, Bottom-to-Top)........................................................................ 16-4
Pins 157–208 (Top, Right-to-Left) ............................................................................. 16-6
Dimensions ............................................................................................................... 16-11
MCF5307 Signal Index............................................................................................... 17-3
Data Pin Configuration ............................................................................................... 17-6
Bus Cycle Size Encoding............................................................................................ 17-7
Bus Cycle Transfer Type Encoding............................................................................ 17-9
TM[2:0] Encodings for TT = 00 (Normal Access)..................................................... 17-9
TM0 Encoding for DMA as Master (TT = 01) ........................................................... 17-9
TM[2:1] Encoding for DMA as Master (TT = 01) ................................................... 17-10
TM[2:0] Encodings for TT = 10 (Emulator Access) ................................................ 17-10
TM[2:0] Encodings for TT = 11 (Interrupt Level) ................................................... 17-10
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Table
Number
17-10
17-11
17-12
17-13
17-14
17-15
17-16
18-1
18-2
18-3
18-4
18-5
18-6
18-7
18-8
18-9
18-10
18-11
18-12
19-1
19-2
19-3
19-4
20-1
20-2
20-3
20-4
20-5
20-6
20-7
20-8
20-9
20-10
20-11
20-12
20-13
20-14
20-15
A-1
A-2
A-3
A-4
A-5
Title
Page
Number
Data Pin Configuration ............................................................................................. 17-12
D7 Selection of CS0 Automatic Acknowledge ........................................................ 17-13
D6 and D5 Selection of CS0 Port Size ..................................................................... 17-13
D4/ADDR_CONFIG, Address Pin Assignment....................................................... 17-13
CLKIN Frequency .................................................................................................... 17-13
BCLKO/PSTCLK Divide Ratios.............................................................................. 17-14
Processor Status Signal Encodings ........................................................................... 17-19
ColdFire Bus Signal Summary ................................................................................... 18-1
Bus Cycle Size Encoding............................................................................................ 18-3
Accesses by Matches in CSCRs and DACRs ............................................................. 18-5
Bus Cycle States ......................................................................................................... 18-6
Allowable Line Access Patterns ............................................................................... 18-12
MCF5307 Arbitration Protocol States ...................................................................... 18-20
ColdFire Bus Arbitration Signal Summary............................................................... 18-21
Cycles for Basic No-Wait-State External Master Access......................................... 18-23
Cycles for External Master Burst Line Access to 32-Bit Port .................................. 18-24
MCF5307 Two-Wire Bus Arbitration Protocol Transition Conditions.................... 18-28
Three-Wire Bus Arbitration Protocol Transition Conditions ................................... 18-32
Data Pin Configuration ............................................................................................. 18-35
JTAG Pin Descriptions ............................................................................................... 19-3
JTAG Instructions....................................................................................................... 19-5
IDCODE Bit Assignments.......................................................................................... 19-6
Boundary-Scan Bit Definitions................................................................................... 19-7
Absolute Maximum Ratings ....................................................................................... 20-1
Operating Temperatures.............................................................................................. 20-1
DC Electrical Specifications ....................................................................................... 20-2
Clock Timing Specification ........................................................................................ 20-2
Input AC Timing Specification................................................................................... 20-3
Output AC Timing Specification ................................................................................ 20-4
Reset Timing Specification....................................................................................... 20-12
Debug AC Timing Specification .............................................................................. 20-12
Timer Module AC Timing Specification.................................................................. 20-14
I2C Input Timing Specifications between SCL and SDA......................................... 20-15
I2C Output Timing Specifications between SCL and SDA ...................................... 20-15
UART Module AC Timing Specifications ............................................................... 20-16
General-Purpose I/O Port AC Timing Specifications............................................... 20-18
DMA AC Timing Specifications .............................................................................. 20-19
IEEE 1149.1 (JTAG) AC Timing Specifications ..................................................... 20-20
SIM Registers............................................................................................................... A-1
Interrupt Controller Registers ...................................................................................... A-1
Chip-Select Registers................................................................................................... A-2
DRAM Controller Registers ........................................................................................ A-3
General-Purpose Timer Registers ................................................................................ A-4
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TABLES
Table
Number
xxx
Page
Number
UART0 Control Registers............................................................................................ A-4
UART1 Control Registers............................................................................................ A-6
Parallel Port Memory Map........................................................................................... A-7
I2C Interface Memory Map.......................................................................................... A-8
DMA Controller Registers........................................................................................... A-8
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A-6
A-7
A-8
A-9
A-10
Title
MCF5307 User’s Manual
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About This Book
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The primary objective of this user’s manual is to define the functionality of the MCF5307
processors for use by software and hardware developers.
The information in this book is subject to change without notice, as described in the
disclaimers on the title page of this book. As with any technical documentation, it is the
readers’ responsibility to be sure they are using the most recent version of the
documentation.
To locate any published errata or updates for this document, refer to the world-wide web at
http://www.motorola.com/coldfire.
Audience
This manual is intended for system software and hardware developers and applications
programmers who want to develop products for the MCF5307. It is assumed that the reader
understands operating systems, microprocessor system design, basic principles of software
and hardware, and basic details of the ColdFire architecture.
Organization
Following is a summary and a brief description of the major sections of this manual:
•
Chapter 1, “Overview,” includes general descriptions of the modules and features
incorporated in the MCF5307, focussing in particular on new features.
•
Part I is intended for system designers who need to understand the operation of the
MCF5307 ColdFire core.
— Chapter 2, “ColdFire Core,” provides an overview of the microprocessor core of
the MCF5307. The chapter begins with a description of enhancements from the
V2 ColdFire core, and then fully describes the V3 programming model as it is
implemented on the MCF5307. It also includes a full description of exception
handling, data formats, an instruction set summary, and a table of instruction
timings.
— Chapter 3, “Hardware Multiply/Accumulate (MAC) Unit,” describes the
MCF5307 multiply/accumulate unit, which executes integer multiply,
multiply-accumulate, and miscellaneous register instructions. The MAC is
integrated into the operand execution pipeline (OEP).
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Organization
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— Chapter 4, “Local Memory.” This chapter describes the MCF5307
implementation of the ColdFire V3 local memory specification. It consists of the
two following major sections.
•
– Section 4.2, “SRAM Overview,” describes the MCF5307 on-chip static RAM
(SRAM) implementation. It covers general operations, configuration, and
initialization. It also provides information and examples showing how to
minimize power consumption when using the SRAM.
– Section 4.7, “Cache Overview,” describes the MCF5307 cache
implementation, including organization, configuration, and coherency. It
describes cache operations and how the cache interacts with other memory
structures.
— Chapter 5, “Debug Support,” describes the Revision C enhanced hardware debug
support in the MCF5307. This revision of the ColdFire debug architecture
encompasses earlier revisions.
Part II, “System Integration Module (SIM),” describes the system integration
module, which provides overall control of the bus and serves as the interface
between the ColdFire core processor complex and internal peripheral devices. It
includes a general description of the SIM and individual chapters that describe
components of the SIM, such as the phase-lock loop (PLL) timing source, interrupt
controller for peripherals, configuration and operation of chip selects, and the
SDRAM controller.
— Chapter 6, “SIM Overview,” describes the SIM programming model, bus
arbitration, and system-protection functions for the MCF5307.
— Chapter 7, “Phase-Locked Loop (PLL),” describes configuration and operation
of the PLL module. It describes in detail the registers and signals that support the
PLL implementation.
— Chapter 8, “I2C Module,” describes the MCF5307 I2C module, including I2C
protocol, clock synchronization, and the registers in the I2C programing model.
It also provides extensive programming examples.
— Chapter 9, “Interrupt Controller,” describes operation of the interrupt controller
portion of the SIM. Includes descriptions of the registers in the interrupt
controller memory map and the interrupt priority scheme.
— Chapter 10, “Chip-Select Module,” describes the MCF5307 chip-select
implementation, including the operation and programming model, which
includes the chip-select address, mask, and control registers.
— Chapter 11, “Synchronous/Asynchronous DRAM Controller Module,”
describes configuration and operation of the synchronous/asynchronous DRAM
controller component of the SIM. It begins with a general description and brief
glossary, and includes a description of signals involved in DRAM operations.
The remainder of the chapter is divided between descriptions of asynchronous
and synchronous operations.
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•
Organization
Part III, “Peripheral Module,” describes the operation and configuration of the
MCF5307 DMA, timer, UART, and parallel port modules, and describes how they
interface with the system integration unit, described in Part II.
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— Chapter 12, “DMA Controller Module,” provides an overview of the DMA
controller module and describes in detail its signals and registers. The latter
sections of this chapter describe operations, features, and supported data transfer
modes in detail, showing timing diagrams for various operations.
•
— Chapter 13, “Timer Module,” describes configuration and operation of the two
general-purpose timer modules, timer 0 and timer 1. It includes programming
examples.
— Chapter 14, “UART Modules,” describes the use of the universal
asynchronous/synchronous receiver/transmitters (UARTs) implemented on the
MCF5307 and includes programming examples.
— Chapter 15, “Parallel Port (General-Purpose I/O),” describes the operation and
programming model of the parallel port pin assignment, direction-control, and
data registers. It includes a code example for setting up the parallel port.
Part IV, “Hardware Interface,” provides a pinout and both electrical and functional
descriptions of the MCF5307 signals. It also describes how these signals interact to
support the variety of bus operations shown in timing diagrams.
— Chapter 16, “Mechanical Data,” provides a functional pin listing and package
diagram for the MCF5307.
— Chapter 17, “Signal Descriptions,” provides an alphabetical listing of MCF5307
signals. This chapter describes the MCF5307 signals. In particular, it shows
which are inputs or outputs, how they are multiplexed, which signals require
pull-up resistors, and the state of each signal at reset.
— Chapter 18, “Bus Operation,” describes data transfers, error conditions, bus
arbitration, and reset operations. It describes transfers initiated by the MCF5307
and by an external bus master, and includes detailed timing diagrams showing
the interaction of signals in supported bus operations. Note that Chapter 11,
“Synchronous/Asynchronous DRAM Controller Module,” describes DRAM
cycles.
— Chapter 19, “IEEE 1149.1 Test Access Port (JTAG),” describes configuration
and operation of the MCF5307 JTAG test implementation. It describes the use of
JTAG instructions and provides information on how to disable JTAG
functionality.
— Chapter 20, “Electrical Specifications,” describes AC and DC electrical
specifications and thermal characteristics for the MCF5307. Because additional
speeds may have become available since the publication of this book, consult
Motorola’s ColdFire web page, http://www.motorola.com/coldfire, to confirm
that this is the latest information.
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Suggested Reading
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This manual includes the following appendix:
•
Appendix A, “List of Memory Maps,” lists the entire address-map for MCF5307
memory-mapped registers.
This manual also includes a glossary and an index.
Suggested Reading
This section lists additional reading that provides background for the information in this
manual as well as general information about the ColdFire architecture.
Freescale Semiconductor, Inc...
General Information
The following documentation provides useful information about the ColdFire architecture
and computer architecture in general:
ColdFire Documentation
The ColdFire documentation is available from the sources listed on the back cover of this
manual. Document order numbers are included in parentheses for ease in ordering.
•
ColdFire Programmers Reference Manual, R1.0 (MCF5200PRM/AD)
•
User’s manuals—These books provide details about individual ColdFire
implementations and are intended to be used in conjunction with The ColdFire
Programmers Reference Manual. These include the following:
•
•
— ColdFire MCF5102 User’s Manual (MCF5102UM/AD)
— ColdFire MCF5202 User’s Manual (MCF5202UM/AD)
— ColdFire MCF5204 User’s Manual (MCF5204UM/AD)
— ColdFire MCF5206 User’s Manual (MCF5206EUM/AD)
— ColdFire MCF5206E User’s Manual (MCF5206EUM/AD)
ColdFire Programmers Reference Manual, R1.0 (MCF5200PRM/AD)
Using Microprocessors and Microcomputers: The Motorola Family, William C.
Wray, Ross Bannatyne, Joseph D. Greenfield
Additional literature on ColdFire implementations is being released as new processors
become available. For a current list of ColdFire documentation, refer to the World Wide
Web at http://www.motorola.com/ColdFire/.
Conventions
This document uses the following notational conventions:
MNEMONICS
In text, instruction mnemonics are shown in uppercase.
mnemonics
In code and tables, instruction mnemonics are shown in lowercase.
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Acronyms and Abbreviations
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italics
0x0
Italics indicate variable command parameters.
Book titles in text are set in italics.
Prefix to denote hexadecimal number
0b0
Prefix to denote binary number
REG[FIELD]
Abbreviations for registers are shown in uppercase. Specific bits,
fields, or ranges appear in brackets. For example, RAMBAR[BA]
identifies the base address field in the RAM base address register.
nibble
A 4-bit data unit
byte
An 8-bit data unit
word
A 16-bit data unit
longword
A 32-bit data unit
x
In some contexts, such as signal encodings, x indicates a don’t care.
n
Used to express an undefined numerical value
¬
NOT logical operator
&
AND logical operator
|
OR logical operator
Acronyms and Abbreviations
Table i lists acronyms and abbreviations used in this document.
Table i. Acronyms and Abbreviated Terms
Term
Meaning
ADC
Analog-to-digital conversion
ALU
Arithmetic logic unit
AVEC
Autovector
BDM
Background debug mode
BIST
Built-in self test
BSDL
Boundary-scan description language
CODEC
Code/decode
DAC
Digital-to-analog conversion
DMA
Direct memory access
DSP
Digital signal processing
EA
Effective address
EDO
Extended data output (DRAM)
FIFO
First-in, first-out
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Acronyms and Abbreviations
Table i. Acronyms and Abbreviated Terms (Continued)
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Term
Meaning
GPIO
General-purpose I/O
I2C
Inter-integrated circuit
IEEE
Institute for Electrical and Electronics Engineers
IFP
Instruction fetch pipeline
IPL
Interrupt priority level
JEDEC
Joint Electron Device Engineering Council
JTAG
Joint Test Action Group
LIFO
Last-in, first-out
LRU
Least recently used
LSB
Least-significant byte
lsb
Least-significant bit
MAC
Multiple accumulate unit
MBAR
Memory base address register
MSB
Most-significant byte
msb
Most-significant bit
Mux
Multiplex
NOP
No operation
OEP
Operand execution pipeline
PC
Program counter
PCLK
Processor clock
PLL
Phase-locked loop
PLRU
Pseudo least recently used
POR
Power-on reset
PQFP
Plastic quad flat pack
RISC
Reduced instruction set computing
Rx
Receive
SIM
System integration module
SOF
Start of frame
TAP
Test access port
TTL
Transistor-to-transistor logic
Tx
Transmit
UART
Universal asynchronous/synchronous receiver transmitter
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Terminology and Notational Conventions
Terminology and Notational Conventions
Table ii shows notational conventions used throughout this document.
Table ii Notational Conventions
Instruction
Operand Syntax
Opcode Wildcard
cc
Logical condition (example: NE for not equal)
An
Any address register n (example: A3 is address register 3)
Register Specifications
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Ay,Ax
Source and destination address registers, respectively
Dn
Any data register n (example: D5 is data register 5)
Dy,Dx
Source and destination data registers, respectively
Rc
Any control register (example VBR is the vector base register)
Rm
MAC registers (ACC, MAC, MASK)
Rn
Any address or data register
Rw
Destination register w (used for MAC instructions only)
Ry,Rx
Any source and destination registers, respectively
Xi
index register i (can be an address or data register: Ai, Di)
Register Names
ACC
MAC accumulator register
CCR
Condition code register (lower byte of SR)
MACSR
MAC status register
MASK
MAC mask register
PC
Program counter
SR
Status register
Port Name
PSTDDATA
Processor status/debug data port
Miscellaneous Operands
#
Í
Immediate data following the 16-bit operation word of the instruction
Effective address
y,x
Source and destination effective addresses, respectively
Assembly language program label
List of registers for MOVEM instruction (example: D3–D0)
Shift operation: shift left ()
Operand data size: byte (B), word (W), longword (L)
bc
Both instruction and data caches
dc
Data cache
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Terminology and Notational Conventions
Table ii Notational Conventions (Continued)
Instruction
ic
#
Operand Syntax
Instruction cache
Identifies the 4-bit vector number for trap instructions
identifies an indirect data address referencing memory
identifies an absolute address referencing memory
dn
Signal displacement value, n bits wide (example: d16 is a 16-bit displacement)
SF
Scale factor (x1, x2, x4 for indexed addressing mode, for MAC operations)
Operations
Freescale Semiconductor, Inc...
+
Arithmetic addition or postincrement indicator
–
Arithmetic subtraction or predecrement indicator
x
Arithmetic multiplication
/
Arithmetic division
~
Invert; operand is logically complemented
&
Logical AND
|
Logical OR
^
Logical exclusive OR
Shift right (example: D0 >> 3 is shift D0 right 3 bits)
→
Source operand is moved to destination operand
←→
Two operands are exchanged
sign-extended
All bits of the upper portion are made equal to the high-order bit of the lower portion
If
then
else
Test the condition. If true, the operations after ‘then’ are performed. If the condition is false and the
optional ‘else’ clause is present, the operations after ‘else’ are performed. If the condition is false
and else is omitted, the instruction performs no operation. Refer to the Bcc instruction description
as an example.
Subfields and Qualifiers
{}
Optional operation
()
Identifies an indirect address
dn
Displacement value, n-bits wide (example: d16 is a 16-bit displacement)
Address
Calculated effective address (pointer)
Bit
Bit selection (example: Bit 3 of D0)
lsb
Least significant bit (example: lsb of D0)
LSB
Least significant byte
LSW
Least significant word
msb
Most significant bit
MSB
Most significant byte
MSW
Most significant word
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Terminology and Notational Conventions
Table ii Notational Conventions (Continued)
Instruction
Operand Syntax
Condition Code Register Bit Names
Carry
N
Negative
V
Overflow
X
Extend
Z
Zero
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C
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Terminology and Notational Conventions
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Chapter 1
Overview
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This chapter is an overview of the MCF5307 ColdFire processor. It includes general
descriptions of the modules and features incorporated in the MCF5307.
1.1 Features
The MCF5307 integrated microprocessor combines a V3 ColdFire processor core with the
following components, as shown in Figure 1-1:
•
•
•
•
•
•
•
•
•
8-Kbyte unified cache
4-Kbyte on-chip SRAM
Integer/fractional multiply-accumulate (MAC) unit
Divide unit
System debug interface
DRAM controller for synchronous and asynchronous DRAM
Four-channel DMA controller
Two general-purpose timers
Two UARTs
•
•
•
I2C™ interface
Parallel I/O interface
System integration module (SIM)
Designed for embedded control applications, the MCF5307 delivers 75 Dhrystone 2.1
MIPS at 90 MHz while minimizing system costs.
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Features
V3 COLDFIRE PROCESSOR COMPLEX
Instruction Unit
JTAG
Branch Logic
CCR
IAG
IC1
IC2
IED
GeneralPurpose
Registers
A0–A7
31
Instruction Fetch
Pipeline (IFP)
Eight-Instruction
FIFO Buffer
0
Operand Execution
Pipeline (OEP)
D0–D7
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31
DIV
0
DSOC
AGEX MAC
Debug
Module
Local
Memory
PSTCLK
SRAM Controller
RAMBAR
4-Kbyte
SRAM
BCLKO
(sent off-chip
and to on-chip
peripherals)
Cache Controller
CACR
CLKIN
PLL
Xn
RSTI
ACR0
ACR1
PCLK
8-Kbyte
Cache
RSTO
31
Local Memory Bus
0
4-Entry
Store
Buffer
DMA
SYSTEM INTEGRATION MODULE (SIM)
PLL Control
System Control
RSR
PLL
SWIVR
Base Address
Bus Master Park
Parallel Port
MBAR
MPARK
PLL
Software
Watchdog
SYPCR SWSR
DRAM Controller
Chip-Select Module
DRAM Control
DCR
8
8
8
CSARs CSCRs CSMRs
External
Bus Interface
Interrupt Controller
I2C Module
10 ICRs
Two UARTs
IRQPAR
IPR
Addr/Cntrl Mask
DACR0/1
IMR
DMR0/1
AVR
8
DRAM Controller
Outputs
CS[7:0]
32-Bit Address Bus
32-Bit Data Bus
Control Signals
4
IRQ[1,3,5,7]
Figure 1-1. MCF5307 Block Diagram
1-2
Four
Channels
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Two
GeneralPurpose
Timers
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Features
Features common to many embedded applications, such as DMAs, various DRAM
controller interfaces, and on-chip memories, are integrated using advanced process
technologies.
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The MCF5307 extends the legacy of Motorola’s 68K family by providing a compatible path
for 68K and ColdFire customers in which development tools and customer code can be
leveraged. In fact, customers moving from 68K to ColdFire can use code translation and
emulation tools that facilitate modifying 68K assembly code to the ColdFire architecture.
Based on the concept of variable-length RISC technology, the ColdFire family combines
the architectural simplicity of conventional 32-bit RISC with a memory-saving,
variable-length instruction set. In defining the ColdFire architecture for embedded
processing applications, a 68K-code compatible core combines performance advantages of
a RISC architecture with the optimum code density of a streamlined, variable-length
M68000 instruction set.
By using a variable-length instruction set architecture, embedded system designers using
ColdFire RISC processors enjoy significant advantages over conventional fixed-length
RISC architectures. The denser binary code for ColdFire processors consumes less memory
than many fixed-length instruction set RISC processors available. This improved code
density means more efficient system memory use for a given application and allows use of
slower, less costly memory to help achieve a target performance level.
The MCF5307 is the first standard product to implement the Version 3 ColdFire
microprocessor core. To reach higher levels of frequency and performance, numerous
enhancements were made to the V2 architecture. Most notable are a deeper instruction
pipeline, branch acceleration, and a unified cache, which together provide 75 (Dhrystone
2.1) MIPS at 90 MHz. Increasing the internal speed of the core also allows higher
performance while providing the system designer with an easy-to-use lower speed system
interface. The processor complex frequency is an integer multiple, 2 to 4 times, of the
external bus frequency. The core clock can be stopped to support a low-power mode.
Serial communication channels are provided by an I2C interface module and two
programmable full-duplex UARTs. Four channels of DMA allow for fast data transfer using
a programmable burst mode independent of processor execution. The two 16-bit
general-purpose multimode timers provide separate input and output signals. For system
protection, the processor includes a programmable 16-bit software watchdog timer. In
addition, common system functions such as chip selects, interrupt control, bus arbitration,
and an IEEE 1149.1 JTAG module are included. A sophisticated debug interface supports
background-debug mode plus real-time trace and debug with expanded flexibility of
on-chip breakpoint registers. This interface is present in all ColdFire standard products and
allows common emulator support across the entire family of microprocessors.
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1.2 MCF5307 Features
The following list summarizes MCF5307 features:
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•
•
•
•
•
1-4
ColdFire processor core
— Variable-length RISC, clock-multiplied Version 3 microprocessor core
— Fully code compatible with Version 2 processors
— Two independent decoupled pipelines: four-stage instruction fetch pipeline (IFP)
and two-stage operand execution pipeline (OEP)
— Eight-instruction FIFO buffer provides decoupling between the pipelines
— Branch prediction mechanisms for accelerating program execution
— 32-bit internal address bus supporting 4 Gbytes of linear address space
— 32-bit data bus
— 16 user-accessible, 32-bit-wide, general-purpose registers
— Supervisor/user modes for system protection
— Vector base register to relocate exception-vector table
— Optimized for high-level language constructs
Multiply and accumulate unit (MAC)
— High-speed, complex arithmetic processing for DSP applications
— Tightly coupled to the OEP
— Three-stage execute pipeline with one clock issue rate for 16 x 16 operations
— 16 x 16 and 32 x 32 multiplies support, all with 32-bit accumulate
— Signed or unsigned integer support, plus signed fractional operands
Hardware integer divide unit
— Unsigned and signed integer divide support
— Tightly coupled to the OEP
— 32/16 and 32/32 operation support producing quotient and/or remainder results
8-Kbyte unified cache
— Four-way set-associative organization
— Operates at higher processor core frequency
— Provides pipelined, single-cycle access to critical code and data
— Supports write-through and copyback modes
— Four-entry, 32-bit store buffer to improve performance of operand writes
4-Kbyte SRAM
— Programmable location anywhere within 4-Gbyte linear address space
— Higher core-frequency operation
— Pipelined, single-cycle access to critical code or data
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•
•
•
•
•
•
MCF5307 Features
DMA controller
— Four fully programmable channels: two support external requests
— Dual-address and single-address transfer support with 8-, 16-, and 32-bit data
capability
— Source/destination address pointers that can increment or remain constant
— 24-bit transfer counter per channel
— Operand packing and unpacking supported
— Auto-alignment transfers supported for efficient block movement
— Bursting and cycle steal support
— Two-bus-clock internal access
— Automatic DMA transfers from on-chip UARTs using internal interrupts
DRAM controller
— Synchronous DRAM (SDRAM), extended-data-out (EDO) DRAM, and fast
page mode support
— Up to 512 Mbytes of DRAM
— Programmable timer provides CAS-before-RAS refresh for asynchronous
DRAMs
— Support for two separate memory blocks
Two UARTs
— Full-duplex operation
— Programmable clock
— Modem control signals available (CTS, RTS)
— Processor-interrupt capability
Dual 16-bit general-purpose multiple-mode timers
— 8-bit prescaler
— Timer input and output pins
— Processor-interrupt capability
— Up to 22-nS resolution at 45 MHz
I2C module
— Interchip bus interface for EEPROMs, LCD controllers, A/D converters, and
keypads
— Fully compatible with industry-standard I2C bus
— Master or slave modes support multiple masters
— Automatic interrupt generation with programmable level
System interface module (SIM)
— Chip selects provide direct interface to 8-, 16-, and 32-bit SRAM, ROM,
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MCF5307 Features
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•
•
•
•
•
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FLASH, and memory-mapped I/O devices
— Eight fully programmable chip selects, each with a base address register
— Programmable wait states and port sizes per chip select
— User-programmable processor clock/input clock frequency ratio
— Programmable interrupt controller
— Low interrupt latency
— Four external interrupt request inputs
— Programmable autovector generator
— Software watchdog timer
16-bit general-purpose I/O interface
IEEE 1149.1 test (JTAG) module
System debug support
— Real-time trace for determining dynamic execution path while in emulator mode
— Background debug mode (BDM) for debug features while halted
— Real-time debug support, including 6 user-visible hardware breakpoint registers
supporting a variety of breakpoint configurations
— Supports comprehensive emulator functions through trace and breakpoint logic
On-chip PLL
— Supports processor clock/bus clock ratios of 66/33, 66/22, 66/16.5, 90/45, 90/30,
and 90/22.5
— Supports low-power mode
Product offerings
— 75 Dhrystone 2.1 MIPS at 90 MHz
— Implemented in 0.35 µ, triple-layer-metal process technology with 3.3-V
operation (5.0-V compliant I/O pads)
— 208-pin plastic QFP package
— 0°–70° C operating temperature
1.2.1 Process
The MCF5307 is manufactured in a 0.35-µ CMOS process with triple-layer-metal routing
technology. This process combines the high performance and low power needed for
embedded system applications. Inputs are 3.3-V tolerant; outputs are CMOS or open-drain
CMOS with outputs operating from VDD + 0.5 V to GND - 0.5 V, with guaranteed
TTL-level specifications.
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ColdFire Module Description
1.3 ColdFire Module Description
The following sections provide overviews of the various modules incorporated in the
MCF5307.
1.3.1 ColdFire Core
The Version 4 ColdFire core consists of two independent and decoupled pipelines to
maximize performance—the instruction fetch pipeline (IFP) and the operand execution
pipeline (OEP).
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1.3.1.1 Instruction Fetch Pipeline (IFP)
The four-stage instruction fetch pipeline (IFP) is designed to prefetch instructions for the
operand execution pipeline (OEP). Because the fetch and execution pipelines are decoupled
by a eight-instruction FIFO buffer, the fetch mechanism can prefetch instructions in
advance of their use by the OEP, thereby minimizing the time stalled waiting for
instructions. To maximize the performance of branch instructions, the Version 3 IFP
implements a branch prediction mechanism. Backward branches are predicted to be taken.
The prediction for forward branches is controlled by a bit in the Condition Code Register
(CCR). These predictions allow the IFP to redirect the fetch stream down the path predicted
to be taken well in advance of the actual instruction execution. The result is significantly
improved performance.
1.3.1.2 Operand Execution Pipeline (OEP)
The prefetched instruction stream is gated from the FIFO buffer into the two-stage OEP.
The OEP consists of a traditional two-stage RISC compute engine with a register file access
feeding an arithmetic/logic unit (ALU). The OEP decodes the instruction, fetches the
required operands and then executes the required function.
1.3.1.3 MAC Module
The MAC unit provides signal processing capabilities for the MCF5307 in a variety of
applications including digital audio and servo control. Integrated as an execution unit in the
processor’s OEP, the MAC unit implements a three-stage arithmetic pipeline optimized for
16 x 16 multiplies. Both 16- and 32-bit input operands are supported by this design in
addition to a full set of extensions for signed and unsigned integers, plus signed, fixed-point
fractional input operands.
1.3.1.4 Integer Divide Module
Integrated into the OEP, the divide module performs operations using signed and unsigned
integers. The module supports word and longword divides producing quotients and/or
remainders.
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ColdFire Module Description
1.3.1.5 8-Kbyte Unified Cache
The MCF5307 architecture includes an 8-Kbyte unified cache. This four-way,
set-associative cache provides pipelined, single-cycle access on cached instructions and
operands.
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As with all ColdFire caches, the cache controller implements a non-lockup, streaming
design. The use of processor-local memories decouples performance from external
memory speeds and increases available bandwidth for external devices or the on-chip
4-channel DMA.
The cache implements line-fill buffers to optimize 16-byte line burst accesses. Additionally,
the cache supports copyback, write-through, or cache-inhibited modes. A 4-entry, 32-bit
buffer is used for cache line push operations and can be configured for deferred write
buffering in write-through or cache-inhibited modes.
1.3.1.6 Internal 4-Kbyte SRAM
The 4-Kbyte on-chip SRAM module provides pipelined, single-cycle access to memory
regions mapped to these devices. The memory can be mapped to any 0-modulo-32K
location in the 4-Gbyte address space. The SRAM module is useful for storing time-critical
functions, the system stack, or heavily-referenced data operands.
1.3.2 DRAM Controller
The MCF5307 DRAM controller provides a direct interface for up to two blocks of DRAM.
The controller supports 8-, 16-, or 32-bit memory widths and can easily interface to PC-100
DIMMs. A unique addressing scheme allows for increases in system memory size without
rerouting address lines and rewiring boards. The controller operates in normal mode or in
page mode and supports SDRAMs and EDO DRAMs.
1.3.3 DMA Controller
The MCF5307 provides four fully programmable DMA channels for quick data transfer.
Dual- and single-address modes support bursting and cycle steal. Data transfers are 32 bits
long with packing and unpacking supported along with an auto-alignment option for
efficient block transfers. Automatic block transfers from on-chip serial UARTs are also
supported through the DMA channels.
1.3.4 UART Modules
The MCF5307 contains two UARTs, which function independently. Either UART can be
clocked by the system bus clock, eliminating the need for an external crystal. Each UART
module interfaces directly to the CPU, as shown in Figure 1-2.
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ColdFire Module Description
UART
Internal Channel
Control Logic
CTS
Serial
Communications
Channel
RTS
RxD
TxD
System Integration
Module (SIM)
Interrupt
Controller
Interrupt Control
Logic
Programmable
Clock
Generation
BCLKO
or
External clock (TIN)
Figure 1-2. UART Module Block Diagram
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Each UART module consists of the following major functional areas:
•
•
•
•
Serial communication channel
16-bit divider for clock generation
Internal channel control logic
Interrupt control logic
Each UART contains an programmable clock-rate generator. Data formats can be 5, 6, 7,
or 8 bits with even, odd, or no parity, and up to 2 stop bits in 1/16 increments. The UARTs
include 4-byte and 2-byte FIFO buffers. The UART modules also provide several
error-detection and maskable-interrupt capabilities. Modem support includes
request-to-send (RTS) and clear-to-send (CTS) lines.
BCLKO provides the time base through a programmable prescaler. The UART time scale
can also be sourced from a timer input. Full-duplex, auto-echo loopback, local loopback,
and remote loopback modes allow testing of UART connections. The programmable
UARTs can interrupt the CPU on various normal or error-condition events.
1.3.5 Timer Module
The timer module includes two general-purpose timers, each of which contains a
free-running 16-bit timer for use in any of three modes. One mode captures the timer value
with an external event. Another mode triggers an external signal or interrupts the CPU when
the timer reaches a set value, while a third mode counts external events.
The timer unit has an 8-bit prescaler that allows programming of the clock input frequency,
which is derived from the system bus cycle or an external clock input pin (TIN). The
programmable timer-output pin generates either an active-low pulse or toggles the output.
1.3.6 I2C Module
The I2C interface is a two-wire, bidirectional serial bus used for quick data exchanges
between devices. The I2C minimizes the interconnection between devices in the end system
and is best suited for applications that need occasional bursts of rapid communication over
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ColdFire Module Description
short distances among several devices. The I2C can operate in master, slave, or
multiple-master modes.
1.3.7 System Interface
The MCF5307 processor provides a direct interface to 8-, 16-, and 32-bit FLASH, SRAM,
ROM, and peripheral devices through the use of fully programmable chip selects and write
enables. Support for burst ROMs is also included. Through the on-chip PLL, users can
input a slower clock (16.6 to 45 MHz) that is internally multiplied to create the faster
processor clock (33.3 to 90 MHz).
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1.3.7.1 External Bus Interface
The bus interface controller transfers information between the ColdFire core or DMA and
memory, peripherals, or other devices on the external bus. The external bus interface
provides up to 32 bits of address bus space, a 32-bit data bus, and all associated control
signals. This interface implements an extended synchronous protocol that supports bursting
operations.
Simple two-wire request/acknowledge bus arbitration between the MCF5307 processor
and another bus master, such as an external DMA device, is glueless with arbitration logic
internal to the MCF5307 processor. Multiple-master arbitration is also available with some
simple external arbitration logic.
1.3.7.2 Chip Selects
Eight fully programmable chip select outputs support the use of external memory and
peripheral circuits with user-defined wait-state insertion. These signals interface to 8-, 16-,
or 32-bit ports. The base address, access permissions, and internal bus transfer terminations
are programmable with configuration registers for each chip select. CS0 also provides
global chip select functionality of boot ROM upon reset for initializing the MCF5307.
1.3.7.3 16-Bit Parallel Port Interface
A 16-bit general-purpose programmable parallel port serves as either an input or an output
on a pin-by-pin basis.
1.3.7.4 Interrupt Controller
The interrupt controller provides user-programmable control of ten internal peripheral
interrupts and implements four external fixed interrupt-request pins. Each internal interrupt
can be programmed to any one of seven interrupt levels and four priority levels within each
of these levels. Additionally, the external interrupt request pins can be mapped to levels 1,
3, 5, and 7 or levels 2, 4, 6, and 7. Autovector capability is available for both internal and
external interrupts.
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1.3.7.5 JTAG
To help with system diagnostics and manufacturing testing, the MCF5307 processor
includes dedicated user-accessible test logic that complies with the IEEE 1149.1a standard
for boundary-scan testability, often referred to as the Joint Test Action Group, or JTAG. For
more information, refer to the IEEE 1149.1a standard.
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1.3.8 System Debug Interface
The ColdFire processor core debug interface is provided to support system debugging in
conjunction with low-cost debug and emulator development tools. Through a standard
debug interface, users can access real-time trace and debug information. This allows the
processor and system to be debugged at full speed without the need for costly in-circuit
emulators. The debug unit in the MCF5307 is a compatible upgrade to the MCF52xx debug
module with added flexibility in the breakpoint registers and a new command to view the
program counter (PC).
The on-chip breakpoint resources include a total of 6 programmable registers—a set of
address registers (with two 32-bit registers), a set of data registers (with a 32-bit data
register plus a 32-bit data mask register), and one 32-bit PC register plus a 32-bit PC mask
register. These registers can be accessed through the dedicated debug serial communication
channel or from the processor’s supervisor mode programming model. The breakpoint
registers can be configured to generate triggers by combining the address, data, and PC
conditions in a variety of single or dual-level definitions. The trigger event can be
programmed to generate a processor halt or initiate a debug interrupt exception.
The MCF5307’s new interrupt servicing options during emulator mode allow real-time
critical interrupt service routines to be serviced while processing a debug interrupt event,
thereby ensuring that the system continues to operate even during debugging.
To support program trace, the Version 3 debug module provides processor status (PST[3:0])
and debug data (DDATA[3:0]) ports. These buses and the PSTCLK output provide
execution status, captured operand data, and branch target addresses defining processor
activity at the CPU’s clock rate.
1.3.9 PLL Module
The MCF5307 PLL module is shown in Figure 1-3.
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Programming Model, Addressing Modes, and Instruction Set
RSTO
PCLK
PSTCLK
CLKIN
PLL
CLKIN X 4
Divide
by 2
Divide by 2,
3, or 4
BCLKO
FREQ[1:0]
RSTI
DIVIDE[1:0]
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Figure 1-3. PLL Module
The PLL module’s three modes of operation are described as follows.
•
•
•
Reset mode—When RSTI is asserted, the PLL enters reset mode. At reset, the PLL
asserts RSTO from the MCF5307. The core:bus frequency ratio and other MCF5307
configuration information are sampled during reset.
Normal mode—In normal mode, the input frequency programmed at reset is
clock-multiplied to provide the processor clock (PCLK).
Reduced-power mode—In reduced-power mode, the PCLK is disabled by executing
a sequence that includes programming a control bit in the system configuration
register (SCR) and then executing the STOP instruction. Register contents are
retained in reduced-power mode, so the system can be reenabled quickly when an
unmasked interrupt or reset is detected.
1.4 Programming Model, Addressing Modes, and
Instruction Set
The ColdFire programming model has two privilege levels—supervisor and user. The S bit
in the status register (SR) indicates the privilege level. The processor identifies a logical
address that differentiates between supervisor and user modes by accessing either the
supervisor or user address space.
•
•
1-12
User mode—When the processor is in user mode (SR[S] = 0), only a subset of
registers can be accessed, and privileged instructions cannot be executed. Typically,
most application processing occurs in user mode. User mode is usually entered by
executing a return from exception instruction (RTE, assuming the value of SR[S]
saved on the stack is 0) or a MOVE, SR instruction (assuming SR[S] is 0).
Supervisor mode—This mode protects system resources from uncontrolled access
by users. In supervisor mode, complete access is provided to all registers and the
entire ColdFire instruction set. Typically, system programmers use the supervisor
programming model to implement operating system functions and provide I/O
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Programming Model, Addressing Modes, and Instruction Set
control. The supervisor programming model provides access to the same registers as
the user model, plus additional registers for configuring on-chip system resources,
as described in Section 1.4.3, “Supervisor Registers.”
Exceptions (including interrupts) are handled in supervisor mode.
1.4.1 Programming Model
Figure 1-4 shows the MCF5307 programming model.
0
D0
D1
D2
D3
D4
D5
D6
D7
Data registers
A0
A1
A2
A3
A4
A5
A6
A7
PC
CCR
Address registers
MACSR
ACC
MASK
MAC status register
MAC accumulator
MAC mask register
SR
VBR
CACR
ACR0
ACR1
RAMBAR
MBAR
Status register
Vector base register
Cache control register
Access control register 0
Access control register 1
RAM base address register
Module base address register
0
User Registers
31
31
Stack pointer
Program counter
Condition code register
0
15
31
Supervisor
Registers
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31
19
(CCR)
Must be zeros
Figure 1-4. ColdFire MCF5307 Programming Model
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Programming Model, Addressing Modes, and Instruction Set
1.4.2 User Registers
The user programming model is shown in Figure 1-4 and summarized in Table 1-1.
Table 1-1. User-Level Registers
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Register
Description
Data registers
(D0–D7)
These 32-bit registers are for bit, byte, word, and longword operands. They can also be used as
index registers.
Address registers
(A0–A7)
These 32-bit registers serve as software stack pointers, index registers, or base address
registers. The base address registers can be used for word and longword operations. A7
functions as a hardware stack pointer during stacking for subroutine calls and exception handling.
Program counter
(PC)
Contains the address of the instruction currently being executed by the MCF5307 processor
Condition code
register (CCR)
The CCR is the lower byte of the SR. It contains indicator flags that reflect the result of a previous
operation and are used for conditional instruction execution.
MAC status
register (MACSR)
Defines the operating configuration of the MAC unit and contains indicator flags from the results
of MAC instructions.
Accumulator
(ACC)
General-purpose register used to accumulate the results of MAC operations
Mask register
(MASK)
General-purpose register provides an optional address mask for MAC instructions that fetch
operands from memory. It is useful in the implementation of circular queues in operand memory.
1.4.3 Supervisor Registers
Table 1-2 summarizes the MCF5307 supervisor-level registers.
Table 1-2. Supervisor-Level Registers
Register
Description
Status register (SR)
The upper byte of the SR provides interrupt information in addition to a variety of mode indicators
signaling the operating state of the ColdFire processor. The lower byte of the SR is the CCR, as
shown in Figure 1-4.
Vector base register
(VBR)
Defines the upper 12 bits of the base address of the exception vector table used during exception
processing. The low-order 20 bits are forced to zero, locating the vector table on 0-modulo-1
Mbyte address.
Cache configuration
register (CACR)
Defines the operating modes of the Version 4 cache memories. Control fields configuring the
instruction, data, and branch cache are provided by this register, along with the default attributes
for the 4-Gbyte address space.
Access control
registers (ACR0/1)
Define address ranges and attributes associated with various memory regions within the 4-Gbyte
address space. Each ACR defines the location of a given memory region and assigns attributes
such as write-protection and cache mode (copyback, write-through, cacheability). Additionally,
CACR fields assign default attributes to the instruction and data memory spaces.
RAM base address
register (RAMBAR)
Provide the logical base address for the 4-Kbyte SRAM module and define attributes and access
types allowed for the SRAM.
Module base address
register (MBAR)
Defines the logical base address for the memory-mapped space containing the control registers
for the on-chip peripherals.
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Programming Model, Addressing Modes, and Instruction Set
1.4.4 Instruction Set
The ColdFire instruction set supports high-level languages and is optimized for those
instructions most commonly generated by compilers in embedded applications. Table 2-8
provides an alphabetized listing of the ColdFire instruction set opcodes, supported
operation sizes, and assembler syntax. For two-operand instructions, the first operand is
generally the source operand and the second is the destination.
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Because the ColdFire architecture provides an upgrade path for 68K customers, its
instruction set supports most of the common 68K opcodes. A majority of the instructions
are binary compatible or optimized 68K opcodes. This feature, when coupled with the code
conversion tools from third-party developers, generally minimizes software porting issues
for customers with 68K applications.
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Programming Model, Addressing Modes, and Instruction Set
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Part I
MCF5307 Processor Core
Intended Audience
Part I is intended for system designers who need a general understanding of the
functionality supported by the MCF5307. It also describes the operation of the MCF5307
Contents
•
•
•
•
Chapter 2, “ColdFire Core,” provides an overview of the microprocessor core of the
MCF5307. The chapter begins with a description of enhancements from the V2
ColdFire core, and then fully describes the V3 programming model as it is
implemented on the MCF5307. It also includes a full description of exception
handling, data formats, an instruction set summary, and a table of instruction
timings.
Chapter 3, “Hardware Multiply/Accumulate (MAC) Unit,” describes the MCF5307
multiply/accumulate unit, which executes integer multiply, multiply-accumulate,
and miscellaneous register instructions. The MAC is integrated into the operand
execution pipeline (OEP).
Chapter 4, “Local Memory.” This chapter describes the MCF5307 implementation
of the ColdFire V3 local memory specification. It consists of the two following
major sections.
— Section 4.2, “SRAM Overview,” describes the MCF5307 on-chip static RAM
(SRAM) implementation. It covers general operations, configuration, and
initialization. It also provides information and examples showing how to
minimize power consumption when using the SRAM.
— Section 4.7, “Cache Overview,” describes the MCF5307 cache implementation,
including organization, configuration, and coherency. It describes cache
operations and how the cache interacts with other memory structures.
Chapter 5, “Debug Support,” describes the Revision C enhanced hardware debug
support in the MCF5307. This revision of the ColdFire debug architecture
encompasses earlier revisions.
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Suggested Reading
The following literature may be helpful with respect to the topics in Part I:
•
•
ColdFire Programmers Reference Manual, R1.0 (MCF5200PRM/AD)
Using Microprocessors and Microcomputers: The Motorola Family, William C.
Wray, Ross Bannatyne, Joseph D. Greenfield
Acronyms and Abbreviations
Table I-i contains acronyms and abbreviations are used in Part I.
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Table I-i. Acronyms and Abbreviated Terms
Term
Meaning
ADC
Analog-to-digital conversion
ALU
Arithmetic logic unit
BDM
Background debug mode
BIST
Built-in self test
BSDL
Boundary-scan description language
CODEC
Code/decode
DAC
Digital-to-analog conversion
DMA
Direct memory access
DSP
Digital signal processing
EA
Effective address
EDO
Extended data output (DRAM)
FIFO
First-in, first-out
GPIO
I2C
Inter-integrated circuit
IEEE
Institute for Electrical and Electronics Engineers
IFP
Instruction fetch pipeline
IPL
Interrupt priority level
JEDEC
Joint Electron Device Engineering Council
JTAG
Joint Test Action Group
LIFO
Last-in, first-out
LRU
Least recently used
LSB
Least-significant byte
lsb
Least-significant bit
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Table I-i. Acronyms and Abbreviated Terms (Continued)
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Term
Meaning
MAC
Multiple accumulate unit
MBAR
Memory base address register
MSB
Most-significant byte
msb
Most-significant bit
Mux
Multiplex
NOP
No operation
OEP
Operand execution pipeline
PC
Program counter
PCLK
Processor clock
PLL
Phase-locked loop
PLRU
Pseudo least recently used
POR
Power-on reset
PQFP
Plastic quad flat pack
RISC
Reduced instruction set computing
Rx
Receive
SIM
System integration module
SOF
Start of frame
TAP
Test access port
TTL
Transistor-to-transistor logic
Tx
Transmit
UART
Universal asynchronous/synchronous receiver transmitter
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Chapter 2
ColdFire Core
This chapter provides an overview of the microprocessor core of the MCF5307. The
chapter begins with a description of enhancements from the Version 2 (V2) ColdFire core,
and then fully describes the V3 programming model as it is implemented on the MCF5307.
It also includes a full description of exception handling, data formats, an instruction set
summary, and a table of instruction timings.
2.1 Features and Enhancements
The MCF5307 is the first standard product to contain a Version 3 ColdFire microprocessor
core. To reach higher levels of frequency and performance, numerous enhancements were
made to the V2 architecture. Most notable are a deeper instruction pipeline, branch
acceleration, and a unified cache, which together provide 75 (Dhrystone 2.1) MIPS at 90
MHz.
The MCF5307 core design emphasizes performance, and backward compatibility
represents the next step on the ColdFire performance roadmap.
The following list summarizes MCF5307 features:
•
•
•
•
•
•
•
•
•
•
Variable-length RISC, clock-multiplied Version 3 microprocessor core
Two independent, decoupled pipelines—four-stage instruction fetch pipeline (IFP)
and two-stage operand execution pipeline (OEP)
Eight-instruction FIFO buffer provides decoupling between the pipelines
Branch prediction mechanisms for accelerating program execution
32-bit internal address bus supporting 4 Gbytes of linear address space
32-bit data bus
16 user-accessible, 32-bit-wide, general-purpose registers
Supervisor/user modes for system protection
Vector base register to relocate exception-vector table
Optimized for high-level language constructs
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Features and Enhancements
2.1.1 Clock-Multiplied Microprocessor Core
The MCF5307 incorporates a clock-multiplying phase-locked loop (PLL). Increasing the
internal speed of the core also allows higher performance while providing the system
designer with an easy-to-use lower speed system interface.
The frequency of the processor complex can be 2x, 3x, or 4x the external bus speed.
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The processor, cache, integrated SRAM, and misalignment module operate at the higher
speed clock (PCLK); other system integrated modules operate at the speed of the bus clock
(BCLKO). When combined with the enhanced pipeline structure of the Version 3 ColdFire
core, the processor and its local memories provide a high level of performance for today’s
demanding embedded applications.
PCLK can be disabled to minimize dissipation when a low-power mode is entered. This is
described in Section 7.2.3, “Reduced-Power Mode.”
2.1.2 Enhanced Pipelines
The IFP prefetches instructions. The OEP decodes instructions, fetches required operands,
then executes the specified function. The two independent, decoupled pipeline structures
maximize performance while minimizing core size. Pipeline stages are shown in Figure 2-1
and are summarized as follows:
•
•
2-22
Four-stage IFP (plus optional instruction buffer stage)
— Instruction address generation (IAG) calculates the next prefetch address.
— Instruction fetch cycle 1 (IC1) initiates prefetch on the processor’s local
instruction bus.
— Instruction fetch cycle 2 (IC2) completes prefetch on the processor’s instruction
local bus.
— Instruction early decode (IED) generates time-critical decode signals needed for
the OEP.
— Instruction buffer (IB) optional stage uses FIFO queue to minimize effects of
fetch latency.
Two-stage OEP
— Decode, select/operand fetch (DSOC) decodes the instruction and selects the
required components for the effective address calculation, or the operand fetch
cycle.
— Address generation/execute (AGEX) Calculates the oeprand address, or
performs the execution of the instruction.
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Features and Enhancements
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Instruction
Fetch
Pipeline
IAG
Instruction
Address
Generation
IC1
Instruction
Fetch Cycle 1
IC2
Instruction
Fetch Cycle 2
IED
Instruction
Early Decode
IB
FIFO
Instruction Buffer
DSOC
Decode & Select,
Operand Fetch
AGEX
Address
Generation,
Execute
Address [31:0]
Data[31:0]
Operand
Execution
Pipeline
Figure 2-1. ColdFire Enhanced Pipeline
2.1.2.1 Instruction Fetch Pipeline (IFP)
Because the fetch and execution pipelines are decoupled by an eight-instruction FIFO
buffer, the IFP can prefetch instructions before the OEP needs them, minimizing stalls.
2.1.2.1.1 Branch Acceleration
Because the IFP and the OEP are decoupled by the instruction buffer, the increased depth
of the IFP is generally hidden from the OEP’s instruction execution. The one exception is
change-of-flow instructions such as unconditional branches or jumps, subroutine calls, and
taken conditional branches. To minimize the effects of the increased depth of the IFP, the
prefetched instruction stream is monitored for change-of-flow opcodes. When certain types
of change-of-flow instructions are detected, the target instruction address is calculated, and
fetching immediately begins in the target stream.
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Features and Enhancements
For example, if an unconditional BRA instruction is detected, the IED calculates the target
of the BRA instruction, and the IAG immediately begins fetching at the target address.
Because of the decoupled nature of the two pipelines, the target instruction is available to
the OEP immediately after the BRA instruction, giving it a single-cycle execution time.
The acceleration logic uses a static prediction algorithm when processing conditional
branch (Bcc) instructions. The default scheme is forward Bcc instructions are predicted as
not-taken, while backward Bcc instructions are predicted as taken. A user-mode control bit,
CCR[7], allows users to dynamically alter the prediction algorithm for forward Bcc
instructions. See Section 2.2.1.5, “Condition Code Register (CCR).
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2.1.2.2 Operand Execution Pipeline (OEP)
The OEP is a two-stage pipeline featuring a traditional RISC datapath with a register file
feeding an arithmetic/logic unit. For simple register-to-register instructions, the first stage
of the OEP performs the instruction decode and fetching of the required register operands
(OC), while the actual instruction execution is performed in the second stage (EX).
For memory-to-register instructions, the instruction is effectively staged through the OEP
twice in the following way:
•
•
•
•
The instruction is decoded and the components of the operand address are selected
(DS).
The operand address is generated using the “execute engine” (AG).
The memory operand is fetched while any register operand is simultaneously
fetched (OC).
The instruction is executed (EX).
For register-to-memory operations, the stage functions (DS/OC, AG/EX) are effectively
performed simultaneously allowing single-cycle execution. For read-modify-write
instructions, the pipeline effectively combines a memory-to-register operation with a store
operation.
2.1.2.2.1 Illegal Opcode Handling
To aid in conversion from M68000 code, every 16-bit operation word is decoded to ensure
that each instruction is valid. If the processor attempts execution of an illegal or
unsupported instruction, an illegal instruction exception (vector 4) is taken.
2.1.2.2.2 Hardware Multiply/Accumulate (MAC) Unit
The MAC is an optional unit in Version 3 that provides hardware support for a limited set
of digital signal processing (DSP) operations used in embedded code, while supporting the
integer multiply instructions in the ColdFire microprocessor family. The MAC features a
three-stage execution pipeline, optimized for 16 x 16 multiplies. It is tightly coupled to the
OEP, which can issue a 16 x 16 multiply with a 32-bit accumulation plus fetch a 32-bit
operand in a single cycle. A 32 x 32 multiply with a 32-bit accumulation requires three
cycles before the next instruction can be issued.
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Features and Enhancements
Figure 2-2 shows basic functionality of the MAC. A full set of instructions are provided for
signed and unsigned integers plus signed, fixed-point fractional input operands.
Operand Y
Operand X
X
Shift 0,1,-1
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+/-
Accumulator
Figure 2-2. ColdFire Multiply-Accumulate Functionality Diagram
The MAC provides functionality in the following three related areas, which are described
in detail in Chapter 3, “Hardware Multiply/Accumulate (MAC) Unit.”
•
•
•
Signed and unsigned integer multiplies
Multiply-accumulate operations with signed and unsigned fractional operands
Miscellaneous register operations
2.1.2.2.3 Hardware Divide Unit
The hardware divide unit performs the following integer division operations:
•
•
•
32-bit operand/16-bit operand producing a 16-bit quotient and a 16-bit remainder
32-bit operand/32-bit operand producing a 32-bit quotient
32-bit operand/32-bit operand producing a 32-bit remainder
2.1.3 Debug Module Enhancements
The ColdFire processor core debug interface supports system integration in conjunction
with low-cost development tools. Real-time trace and debug information can be accessed
through a standard interface, which allows the processor and system to be debugged at full
speed without costly in-circuit emulators. The MCF5307 debug unit is a compatible
upgrade to the MCF52xx debug module with enhancements that include:
•
•
•
A new command to obtain the value of the program counter (PC)
Allowing ORing of terms in creating breakpoints
Increased flexibility of the breakpoint registers
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Programming Model
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On-chip breakpoint resources include the following:
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•
•
•
•
•
•
Configuration/status register (CSR)
Background debug mode (BDM) address attributes register (BAAR)
Bus attributes and mask register (AATR)
Breakpoint registers. These can be used to define triggers combining address, data,
and PC conditions in single- or dual-level definitions. They include the following:
— PC breakpoint register (PBR)
— PC breakpoint mask register (PBMR)
— Data operand address breakpoint registers (ABHR/ABLR)
— Data breakpoint register (DBR)
Data breakpoint mask register (DBMR)
Trigger definition register (TDR) can be programmed to generate a processor halt or
initiate a debug interrupt exception.
These registers can be accessed through the dedicated debug serial communication channel,
or from the processor’s supervisor programming model, using the WDEBUG instruction.
The enhancements of the Revision B debug specification are fully backward-compatible
with the A revision. For more information, see Chapter 5, “Debug Support.”
2.2 Programming Model
The MCF5307 programming model consists of three instruction and register groups—user,
MAC (also user-mode), and supervisor, shown in Figure 2-2. User mode programs are
restricted to user and MAC instructions and programming models. Supervisor-mode
system software can reference all user-mode and MAC instructions and registers and
additional supervisor instructions and control registers. The user or supervisor
programming model is selected based on SR[S]. The following sections describe the
registers in the user, MAC, and supervisor programming models.
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31
0
D0
D1
D2
D3
D4
D5
D6
D7
Data registers
A0
A1
A2
A3
A4
A5
A6
A7
PC
CCR
Address registers
MACSR
ACC
MASK
MAC status register
MAC accumulator
MAC mask register
SR
VBR
CACR
ACR0
ACR1
RAMBAR
MBAR
Status register
Vector base register
Cache control register
Access control register 0
Access control register 1
RAM base address register
Module base address register
0
User Registers
31
31
Stack pointer
Program counter
Condition code register
0
15
31
Supervisor
Registers
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Programming Model
19
(CCR)
Must be zeros
Figure 2-3. ColdFire Programming Model
2.2.1 User Programming Model
As Figure 2-3 shows, the user programming model consists of the following registers:
•
•
•
16 general-purpose 32-bit registers, D0–D7 and A0–A7
32-bit program counter
8-bit condition code register
2.2.1.1 Data Registers (D0–D7)
Registers D0–D7 are used as data registers for bit, byte (8-bit), word (16-bit), and longword
(32-bit) operations. They may also be used as index registers.
2.2.1.2 Address Registers (A0–A6)
The address registers (A0–A6) can be used as software stack pointers, index registers, or
base address registers and may be used for word and longword operations.
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Programming Model
2.2.1.3 Stack Pointer (A7, SP)
The processor core supports a single hardware stack pointer (A7) used during stacking for
subroutine calls, returns, and exception handling. The stack pointer is implicitly referenced
by certain operations and can be explicitly referenced by any instruction specifying an
address register. The initial value of A7 is loaded from the reset exception vector, address
0x0000. The same register is used for user and supervisor modes, and may be used for word
and longword operations.
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A subroutine call saves the program counter (PC) on the stack and the return restores the
PC from the stack. The PC and the status register (SR) are saved on the stack during
exception and interrupt processing. The return from exception instruction restores SR and
PC values from the stack.
2.2.1.4 Program Counter (PC)
The PC holds the address of the executing instruction. For sequential instructions, the
processor automatically increments PC. When program flow changes, the PC is updated
with the target instruction. For some instructions, the PC specifies the base address for
PC-relative operand addressing modes.
2.2.1.5 Condition Code Register (CCR)
The CCR, Figure 2-4, occupies SR[7–0], as shown in Figure 2-3. CCR[4–0] are indicator
flags based on results generated by arithmetic operations.
Table 2-1 describes the CCR fieldsMAC Programming ModelFigure 2-3 shows the registers in the MAC portion of the user programming model. These registers are described as follows:Accumulator (ACC)—This 32-bit, read/write, general-purpose register is used to accumulate the results of MAC operations.
7
6
5
Field
P
—
Reset
0
00
R/W
R
R/W
4
3
2
1
0
X
N
Z
V
C
R/W
R/W
Undefined
R/W
R/W
R/W
Table 2-1. CCR Field Descriptions
Bits
Name
Description
7
P
Branch prediction bit. Alters the static prediction algorithm used by the branch acceleration logic in the
IFP on forward conditional branches.
0 Predicted as not-taken.
1 Predicted as taken.
6–5
—
Reserved, should be cleared.
4
X
Extend condition code bit. Assigned the value of the carry bit for arithmetic operations; otherwise not
affected or set to a specified result. Also used as an input operand for multiple-precision arithmetic.
3
N
Negative condition code bit. Set if the msb of the result is set; otherwise cleared.
2
Z
Zero condition code bit. Set if the result equals zero; otherwise cleared.
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Programming Model
Table 2-1. CCR Field Descriptions (Continued)
Bits
Name
1
V
Overflow condition code bit. Set if an arithmetic overflow occurs, implying that the result cannot be
represented in the operand size; otherwise cleared.
0
C
Carry condition code bit. Set if a carry-out of the data operand msb occurs for an addition or if a
borrow occurs in a subtraction; otherwise cleared.
•
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•
Description
Mask register (MASK)—This 16-bit general-purpose register provides an optional
address mask for MAC instructions that fetch operands from memory. It is useful in
the implementation of circular queues in operand memory.
MAC status register (MACSR)—This 8-bit register defines configuration of the
MAC unit and contains indicator flags affected by MAC instructions. Unless noted
otherwise, MACSR indicator flag settings are based on the final result, that is, the
result of the final operation involving the product and accumulator.
2.2.2 Supervisor Programming Model
The MCF5307 supervisor programming model is shown in Figure 2-3. Typically, system
programmers use the supervisor programming model to implement operating system
functions and provide memory and I/O control. The supervisor programming model
provides access to the user registers and additional supervisor registers, which include the
upper byte of the status register (SR), the vector base register (VBR), and registers for
configuring attributes of the address space connected to the Version 3 processor core. Most
supervisor-mode registers are accessed by using the MOVEC instruction with the control
register definitions in Table 2-2.
Table 2-2. MOVEC Register Map
Rc[11–0]
Register Definition
0x002
Cache control register (CACR)
0x004
Access control register 0 (ACR0)
0x005
Access control register 1 (ACR1)
0x801
Vector base register (VBR)
0xC04
RAM base address register (RAMBAR)
0xC0F
Module base address register (MBAR)
2.2.2.1 Status Register (SR)
The SR stores the processor status, the interrupt priority mask, and other control bits.
Supervisor software can read or write the entire SR; user software can read or write only
SR[7–0], described in Section 2.2.1.5, “Condition Code Register (CCR).” The control bits
indicate processor states—trace mode (T), supervisor or user mode (S), and master or
interrupt state (M). SR is set to 0x27xx after reset.
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Programming Model
15
14
13
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12
11
10
9
8
7
6
System byte
Field
T
Reset
0
—
R/W R/W
S
M
—
5
4
3
2
1
0
V
C
Condition code register (CCR)
I
P
—
X
N
Z
0
1
0
0
111
0
00
—
—
—
—
—
R
R/W
R/W
R
R/W
R/W
R
R/W
R/W
R/W
R/W
R/W
Figure 2-5. Status Register (SR)
Table 2-3 describes SR fields.
Table 2-3. Status Field Descriptions
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Bits
Name
Description
15
T
Trace enable. When T is set, the processor performs a trace exception after every instruction.
13
S
Supervisor/user state. Indicates whether the processor is in supervisor or user mode
0 User mode
1 Supervisor mode
12
M
Master/interrupt state. Cleared by an interrupt exception. It can be set by software during execution
of the RTE or move to SR instructions so the OS can emulate an interrupt stack pointer.
10–8
I
Interrupt priority mask. Defines the current interrupt priority. Interrupt requests are inhibited for all
priority levels less than or equal to the current priority, except the edge-sensitive level-7 request,
which cannot be masked.
7–0
CCR
Condition code register. See Table 2-1.
2.2.2.2 Vector Base Register (VBR)
The VBR holds the base address of the exception vector table in memory. The displacement
of an exception vector is added to the value in this register to access the vector table.
VBR[19–0] are not implemented and are assumed to be zero, forcing the vector table to be
aligned on a 0-modulo-1-Mbyte boundary.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
Field
Reset
Exception vector table base address
9
8
7
6
5
4
3
2
1
0
—
0000_0000_0000_0000_0000_0000_0000_0000
R/W Written from a BDM serial command or from the CPU using the MOVEC instruction. VBR can be read from
the debug module only. The upper 12 bits are returned, the low-order 20 bits are undefined.
Rc[11–0]
0x801
Figure 2-6. Vector Base Register (VBR)
2.2.2.3 Cache Control Register (CACR)
The CACR controls operation of both the instruction and data cache memory. It includes
bits for enabling, freezing, and invalidating cache contents. It also includes bits for defining
the default cache mode and write-protect fields. See Section 4.10.1, “Cache Control
Register (CACR).”
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Integer Data Formats
2.2.2.4 Access Control Registers (ACR0–ACR1)
The access control registers (ACR0–ACR1) define attributes for two user-defined memory
regions. Attributes include definition of cache mode, write protect and buffer write enables.
See Section 4.10.2, “Access Control Registers (ACR0–ACR1).”
2.2.2.5 RAM Base Address Register (RAMBAR)
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The RAMBAR register determines the base address location of the internal SRAM module
and indicates the types of references mapped to it. The RAMBAR includes a base address,
write-protect bit, address space mask bits, and an enable. The RAM base address must be
aligned on a 0-modulo-32-Kbyte boundary. See Section 4.4.1, “SRAM Base Address
Register (RAMBAR).”
2.2.2.6 Module Base Address Register (MBAR)
The module base address register (MBAR) defines the logical base address for the
memory-mapped space containing the control registers for the on-chip peripherals. See
Section 6.2.2, “Module Base Address Register (MBAR).”
2.3 Integer Data Formats
Table 2-4 lists the integer operand data formats. Integer operands can reside in registers,
memory, or instructions. The operand size for each instruction is either explicitly encoded
in the instruction or implicitly defined by the instruction operation.
Table 2-4. Integer Data Formats
Operand Data Format
Size
Bit
1 bit
Byte integer
8 bits
Word integer
16 bits
Longword integer
32 bits
2.4 Organization of Data in Registers
The following sections describe data organization within the data, address, and control
registers.
2.4.1 Organization of Integer Data Formats in Registers
Figure 2-7 shows the integer format for data registers. Each integer data register is 32 bits
wide. Byte and word operands occupy the lower 8- and 16-bit portions of integer data
registers, respectively. Longword operands occupy the entire 32 bits of integer data
registers. A data register that is either a source or destination operand only uses or changes
the appropriate lower 8 or 16 bits in byte or word operations, respectively. The remaining
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Organization of Data in Registers
high-order portion does not change. The least significant bit (lsb) of all integer sizes is zero,
the most-significant bit (msb) of a longword integer is 31, the msb of a word integer is 15,
and the msb of a byte integer is 7.
31
30
1
0
msb
lsb
31
7
Not used
31
0
msb Low order byte
lsb
Lower order word
lsb
15
Not used
msb
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Byte (8 bits)
0
31
msb
Bit (0 ≤ bit number ≤ 31)
Word (16 bits)
0
Longword
lsb
Longword (32 bits)
Figure 2-7. Organization of Integer Data Formats in Data Registers
The instruction set encodings do not allow the use of address registers for byte-sized
operands. When an address register is a source operand, either the low-order word or the
entire longword operand is used, depending on the operation size. Word-length source
operands are sign-extended to 32 bits and then used in the operation with anaddress register
destination. When an address register is a destination, the entire register is affected,
regardless of the operation size. Figure 2-8 shows integer formats for address registers.
31
16
Sign-Extended
15
0
16-Bit Address Operand
31
0
Full 32-Bit Address Operand
Figure 2-8. Organization of Integer Data Formats in Address Registers
The size of control registers varies according to function. Some have undefined bits
reserved for future definition by Motorola. Those particular bits read as zeros and must be
written as zeros for future compatibility.
All operations to the SR and CCR are word-size operations. For all CCR operations, the
upper byte is read as all zeros and is ignored when written, regardless of privilege mode.
2.4.2 Organization of Integer Data Formats in Memory
All ColdFire processors use a big-endian addressing scheme. The byte-addressable
organization of memory allows lower addresses to correspond to higher order bytes. The
address N of a longword data item corresponds to the address of the high-order word. The
lower order word is located at address N + 2. The address N of a word data item corresponds
to the address of the high-order byte. The lower order byte is located at address N + 1. This
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Addressing Mode Summary
organization is shown in Figure 2-9.
31
23
15
7
0
Longword 0x0000_0000
Word 0x0000_0000
Byte 0x0000_0000
Word 0x0000_0002
Byte 0x0000_0001
Byte 0x0000_0002
Byte 0x0000_0003
Longword 0x0000_0004
Word 0x0000_0004
Byte 0x0000_0004
Word 0x0000_0006
Byte 0x0000_0005
Byte 0x0000_0006
Byte 0x0000_0007
.
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.
.
Longword 0xFFFF_FFFC
Word 0xFFFF_FFFC
Byte 0xFFFF_FFFC
Byte 0xFFFF_FFFD
Word 0xFFFF_FFFE
Byte 0xFFFF_FFFE
Byte 0xFFFF_FFFF
Figure 2-9. Memory Operand Addressing
2.5 Addressing Mode Summary
Addressing modes are categorized by how they are used. Data addressing modes refer to
data operands. Memory addressing modes refer to memory operands. Alterable addressing
modes refer to alterable (writable) data operands. Control addressing modes refer to
memory operands without an associated size.
These categories sometimes combine to form more restrictive categories. Two combined
classifications are alterable memory (both alterable and memory) and data alterable (both
alterable and data). Twelve of the most commonly used effective addressing modes from
the M68000 Family are available on ColdFire microprocessors. Table 2-5 summarizes
these modes and their categories;
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Instruction Set Summary
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Table 2-5. ColdFire Effective Addressing Modes
Addressing Modes
Reg.
Field
Dn
An
000
001
(An)
(An)+
–(An)
(d16, An)
Category
Data
Memory
Control
Alterable
reg. no.
reg. no.
X
—
—
—
—
—
X
X
010
011
100
101
reg. no.
reg. no.
reg. no.
reg. no.
X
X
X
X
X
X
X
X
X
—
—
X
X
X
X
X
(d8, An,
Xi)
110
reg. no.
X
X
X
X
Program counter indirect
with displacement
(d16, PC)
111
010
X
X
X
—
Program counter indirect
with index
8-bit displacement
(d8, PC,
Xi)
111
011
X
X
X
—
Absolute data addressing
Short
Long
(xxx).W
(xxx).L
111
111
000
001
X
X
X
X
X
X
—
—
Immediate
#
111
100
X
X
—
—
Register direct
Data
Address
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Mode
Field
Syntax
Register indirect
Address
Address with
Postincrement
Address with
Predecrement
Address with
Displacement
Address register indirect with
index
8-bit displacement
2.6 Instruction Set Summary
The ColdFire instruction set is a simplified version of the M68000 instruction set. The
removed instructions include BCD, bit field, logical rotate, decrement and branch, and
integer multiply with a 64-bit result. Nine new MAC instructions have been added.
Table 2-6 lists notational conventions used throughout this manual.
Table 2-6. Notational Conventions
Instruction
Operand Syntax
Opcode Wildcard
cc
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Logical condition (example: NE for not equal)
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Instruction Set Summary
Table 2-6. Notational Conventions (Continued)
Instruction
Operand Syntax
Register Specifications
An
Any address register n (example: A3 is address register 3)
Ay,Ax
Source and destination address registers, respectively
Dn
Any data register n (example: D5 is data register 5)
Dy,Dx
Source and destination data registers, respectively
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Rc
Any control register (example VBR is the vector base register)
Rm
MAC registers (ACC, MAC, MASK)
Rn
Any address or data register
Rw
Destination register w (used for MAC instructions only)
Ry,Rx
Any source and destination registers, respectively
Xi
index register i (can be an address or data register: Ai, Di)
Register Names
ACC
MAC accumulator register
CCR
Condition code register (lower byte of SR)
MACSR
MAC status register
MASK
MAC mask register
PC
Program counter
SR
Status register
Port Name
DDATA
Debug data port
PST
Processor status port
Miscellaneous Operands
#
Í
Immediate data following the 16-bit operation word of the instruction
Effective address
y,x
Source and destination effective addresses, respectively
Assembly language program label
List of registers for MOVEM instruction (example: D3–D0)
Shift operation: shift left ()
Operand data size: byte (B), word (W), longword (L)
uc
#
Unified cache
Identifies the 4-bit vector number for trap instructions
identifies an indirect data address referencing memory
identifies an absolute address referencing memory
dn
Signal displacement value, n bits wide (example: d16 is a 16-bit displacement)
SF
Scale factor (x1, x2, x4 for indexed addressing mode, for MAC operations)
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Instruction Set Summary
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Table 2-6. Notational Conventions (Continued)
Instruction
Operand Syntax
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Operations
+
Arithmetic addition or postincrement indicator
–
Arithmetic subtraction or predecrement indicator
x
Arithmetic multiplication
/
Arithmetic division
~
Invert; operand is logically complemented
&
Logical AND
|
Logical OR
^
Logical exclusive OR
Shift right (example: D0 >> 3 is shift D0 right 3 bits)
→
Source operand is moved to destination operand
←→
Two operands are exchanged
sign-extended
All bits of the upper portion are made equal to the high-order bit of the lower portion
If
then
else
Test the condition. If the condition is true, the operations in the then clause are performed. If the
condition is false and the optional else clause is present, the operations in the else claue are
performed. If the condition is false and the else clause is omitted, the instruction performs no
operation. Refer to the Bcc instruction description as an example.
Subfields and Qualifiers
{}
Optional operation
()
Identifies an indirect address
dn
Displacement value, n-bits wide (example: d16 is a 16-bit displacement)
Address
Bit
lsb
Calculated effective address (pointer)
Bit selection (example: Bit 3 of D0)
Least significant bit (example: lsb of D0)
LSB
Least significant byte
LSW
Least significant word
msb
Most significant bit
MSB
Most significant byte
MSW
Most significant word
Condition Code Register Bit Names
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Instruction Set Summary
Table 2-6. Notational Conventions (Continued)
Instruction
Operand Syntax
P
Branch prediction
C
Carry
N
Negative
V
Overflow
X
Extend
Z
Zero
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2.6.1 Instruction Set Summary
Table 2-7 lists implemented user-mode instructions by opcode.
Table 2-7. User-Mode Instruction Set Summary
Instruction
Operand Syntax
Operand Size
Operation
ADD
Dy,x
y,Dx
.L
.L
Source + destination → destination
ADDA
y,Ax
.L
Source + destination → destination
ADDI
#,Dx
.L
Immediate data + destination → destination
ADDQ
#,x
.L
Immediate data + destination → destination
ADDX
Dy,Dx
.L
Source + destination + X → destination
AND
Dy,x
y,Dx
.L
.L
Source & destination → destination
ANDI
#,Dx
.L
Immediate data & destination → destination
ASL
Dy,Dx
#,Dx
.L
.L
X/C ← (Dx Dy) → X/C
MSB → (Dx >> #) → X/C
Bcc
.B,.W
If condition true, then PC + 2 + dn → PC
BCHG
Dy,x
#,x
.B,.L
.B,.L
~( of destination) → Z,
Bit of destination
BCLR
Dy,x
#,x
.B,.L
.B,.L
~( of destination) → Z;
0 → bit of destination
BRA
.B,.W
PC + 2 + dn → PC
BSET
Dy,x
#,x
.B,.L
.B,.L
~( of destination) → Z;
1→ bit of destination
BSR
.B,.W
SP – 4 → SP; next sequential PC→ (SP); PC + 2 + dn → PC
BTST
Dy,x
#,x
.B,.L
.B,.L
~( of destination) → Z
CLR
y,Dx
.B,.W,.L
0 → destination
CMP
y,Ax
.L
Destination – source
CMPA
y,Dx
.L
Destination – source
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Instruction Set Summary
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Table 2-7. User-Mode Instruction Set Summary (Continued)
Freescale Semiconductor, Inc...
Instruction
Operand Syntax
Operand Size
Operation
CMPI
y,Dx
.L
Destination – immediate data
DIVS
y,Dx
y,Dx
.W
.L
Dx /y → Dx {16-bit remainder; 16-bit quotient}
Dx /y → Dx {32-bit quotient}
Signed operation
DIVU
y,Dx
Dy,x
.W
.L
Dx /y → Dx {16-bit remainder; 16-bit quotient}
Dx /y → Dx {32-bit quotient}
Unsigned operation
EOR
Dy,x
.L
Source ^ destination → destination
EORI
#,Dx
.L
Immediate data ^ destination → destination
EXT
#,Dx
.B →.W
.W →.L
Sign-extended destination → destination
EXTB
Dx
.B →.L
Sign-extended destination → destination
HALT1
None
Unsized
Enter halted state
JMP
y
Unsized
Address of → PC
JSR
y
Unsized
SP – 4 → SP; next sequential PC → (SP); → PC
LEA
y,Ax
.L
→ Ax
LINK
Ax,#
.W
SP – 4 → SP; Ax → (SP); SP → Ax; SP + d16 → SP
LSL
Dy,Dx
#,Dx
.L
.L
X/C ← (Dx Dy) → X/C
0 → (Dx >> #) → X/C
MAC
Ry,RxSF
.L + (.W × .W) → .L
.L + (.L × .L) → .L
ACC + (Ry × Rx){> 1} → ACC
ACC + (Ry × Rx){> 1} → ACC; (y{&MASK}) →
Rw
MACL
Ry,RxSF,y,Rw
.L + (.W × .W) → .L, .L
.L + (.L × .L) → .L, .L
ACC + (Ry × Rx){> 1} → ACC
ACC + (Ry × Rx){> 1} → ACC; (y{&MASK})
→ Rw
MOVE
y,x
.B,.W,.L
y → x
MOVE from
MAC
MASK,Rx
ACC,Rx
MACSR,Rx
.L
Rm → Rx
MACSR,CCR
.L
MACSR → CCR
Ry,ACC
Ry,MACSR
Ry,MASK
.L
Ry → Rm
#,ACC
#,MACSR
#,MASK
.L
# → Rm
MOVE from
CCR
CCR,Dx
.W
CCR → Dx
MOVE to
CCR
Dy,CCR
#,CCR
.B
Dy → CCR
# → CCR
MOVEA
y,Ax
.W,.L → .L
Source → destination
MOVE to
MAC
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Instruction Set Summary
Table 2-7. User-Mode Instruction Set Summary (Continued)
Freescale Semiconductor, Inc...
Instruction
Operand Syntax
Operand Size
Operation
MOVEM
#,x
y,#
.L
.L
Listed registers → destination
Source → listed registers
MOVEQ
#,Dx
.B → .L
Sign-extended immediate data → destination
MSAC
Ry,RxSF
.L - (.W × .W) → .L
.L - (.L × .L) → .L
ACC – (Ry × Rx){> 1} → ACC
MSACL
Ry,RxSF,y,Rw
.L - (.W × .W) → .L, .L
.L - (.L × .L) → .L, .L
ACC – (Ry × Rx){> 1} → ACC;
(y{&MASK}) → Rw
MULS
y,Dx
.W X .W → .L
.L X .L → .L
Source × destination → destination
Signed operation
MULU
y,Dx
.W X .W → .L
.L X .L → .L
Source × destination → destination
Unsigned operation
NEG
Dx
.L
0 – destination → destination
NEGX
Dx
.L
0 – destination – X → destination
NOP
none
Unsized
Synchronize pipelines; PC + 2 → PC
NOT
Dx
.L
~ Destination → destination
OR
y,Dx
Dy,x
.L
Source | destination → destination
ORI
#,Dx
.L
Immediate data | destination → destination
PEA
y
.L
SP – 4 → SP; Address of → (SP)
PULSE
none
Unsized
Set PST= 0x4
REMS
,Dx
.L
Dx/y → Dw {32-bit remainder}
Signed operation
REMU
,Dx
.L
Dx/y → Dw {32-bit remainder}
Unsigned operation
RTS
none
Unsized
(SP) → PC; SP + 4 → SP
Scc
Dx
.B
If condition true, then 1s destination;
Else 0s → destination
SUB
y,Dx
Dy,x
.L
.L
Destination – source → destination
SUBA
y,Ax
.L
Destination – source → destination
SUBI
#,Dx
.L
Destination – immediate data → destination
SUBQ
#,x
.L
Destination – immediate data → destination
SUBX
Dy,Dx
.L
Destination – source – X → destination
SWAP
Dx
.W
MSW of Dx ←→ LSW of Dx
TRAP
#
Unsized
SP – 4 → SP;PC → (SP);
SP – 2 → SP;SR → (SP);
SP – 2 → SP; format → (SP);
Vector address → PC
TRAPF
None
#
Unsized
.W
.L
PC + 2 → PC
PC + 4 → PC
PC + 6 → PC
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Instruction Timing
Freescale Semiconductor, Inc.
Table 2-7. User-Mode Instruction Set Summary (Continued)
Instruction
Operand Syntax
Operand Size
Operation
TST
y
.B,.W,.L
Set condition codes
UNLK
Ax
Unsized
Ax →SP; (SP) → Ax; SP + 4 → SP
WDDATA
y
.B,.W,.L
y →DDATA port
1
By default the HALT instruction is a supervisor-mode instruction; however, it can be configured to allow user-mode
execution by setting CSR[UHE].
Table 2-8 describes supervisor-mode instructions.
Table 2-8. Supervisor-Mode Instruction Set Summary
Freescale Semiconductor, Inc...
Instruction
CPUSHL
Operand Syntax
Operand Size
(An)
Unsized
Operation
Invalidate instruction cache line
Push and invalidate data cache line
Push data cache line and invalidate (I,D)-cache lines
HALT1
none
Unsized
Enter halted state
MOVE from SR
SR, Dx
.W
SR → Dx
MOVE to SR
Dy,SR
.W
Source → SR
#,SR
MOVEC
Ry,Rc
.L
Ry → Rc
Rc
Register Definition
0x002
0x004
0x005
0x006
0x007
0x801
0xC04
0xC05
Cache control register (CACR)
Access control register 0 (ACR0)
Access control register 1 (ACR1)
Access control register 2 (ACR2)
Access control register 3 (ACR3)
Vector base register (VBR)
RAM base address register 0 (RAMBAR0)
RAM base address register 1 (RAMBAR1)
RTE
None
Unsized
(SP+2) → SR; SP+4 → SP; (SP) → PC; SP + formatfield SP
STOP
#
.W
Immediate data → SR; enter stopped state
WDEBUG
y
.L
y → debug module
1
The HALT instruction can be configured to allow user-mode execution by setting CSR[UHE].
2.7 Instruction Timing
The timing data presented in this section assumes the following:
•
•
2-40
The OEP is loaded with the opword and all required extension words at the
beginning of each instruction execution. This implies that the OEP spends no time
waiting for the IFP to supply opwords and/or extension words.
The OEP experiences no sequence-related pipeline stalls. For the MCF5307, the
most common example of this type of stall involves consecutive store operations,
excluding the MOVEM instruction. For all store operations (except MOVEM),
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certain hardware resources within the processor are marked as “busy” for two clock
cycles after the final DSOC cycle of the store instruction. If a subsequent store
instruction is encountered within this two-cycle window, it is stalled until the
resource again becomes available. Thus, the maximum pipeline stall involving
consecutive store operations is two cycles.
The OEP can complete all memory accesses without memory causing any stall
conditions. Thus, timing details in this section assume an infinite zero-wait state
memory attached to the core.
All operand data accesses are assumed to be aligned on the same byte boundary as
the operand size:
— 16-bit operands aligned on 0-modulo-2 addresses
— 32-bit operands aligned on 0-modulo-4 addresses
Operands that do not meet these guidelines are misaligned. Table 2-9 shows how the
core decomposes a misaligned operand reference into a series of aligned accesses.
•
•
Freescale Semiconductor, Inc...
Instruction Timing
Table 2-9. Misaligned Operand References
1
Additional C(R/W) 1
A[1:0]
Size
Bus Operations
x1
Word
Byte, Byte
2(1/0) if read
1(0/1) if write
x1
Long
Byte, Word, Byte
3(2/0) if read
2(0/2) if write
10
Long
Word, Word
2(1/0) if read
1(0/1) if write
Each timing entry is presented as C(r/w), described as follows:
C is the number of processor clock cycles, including all applicable operand fetches and writes, as
well as all internal core cycles required to complete the instruction execution.
r/w is the number of operand reads (r) and writes (w) required by the instruction. An operation
performing a read-modify write function is denoted as (1/1).
2.7.1 MOVE Instruction Execution Times
The execution times for the MOVE.{B,W,L} instructions are shown in the next tables.
Table 2-12 shows the timing for the other generic move operations.
NOTE:
For all tables in this chapter, the execution time of any
instruction using the PC-relative effective addressing modes is
equivalent to the time using comparable An-relative mode.
ET with { = (d16,PC)} equals ET with { = (d16,An)}
ET with { = (d8,PC,Xi*SF)} equals ET with { = (d8,An,Xi*SF)}
The nomenclature “(xxx).wl” refers to both forms of absolute
addressing, (xxx).w and (xxx).l.
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Instruction Timing
Table 2-10 lists execution times for MOVE.{B,W} instructions.
Table 2-10. Move Byte and Word Execution Times
Destination
Freescale Semiconductor, Inc...
Source
Rx
(Ax)
(Ax)+
-(Ax)
(d16,Ax)
(d8,Ax,Xi*SF)
(xxx).wl
Dy
1(0/0)
1(0/1)
1(0/1)
1(0/1)
1(0/1)
2(0/1)
1(0/1)
Ay
1(0/0)
1(0/1)
1(0/1)
1(0/1)
1(0/1)
2(0/1)
1(0/1)
(Ay)
4(1/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
(Ay)+
4(1/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
-(Ay)
4(1/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
(d16,Ay)
4(1/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
—
—
(d8,Ay,Xi*SF)
5(1/0)
5(1/1)
5(1/1)
5(1/1)
—
—
—
(xxx).w
4(1/0)
4(1/1)
4(1/1)
4(1/1)
—
—
—
—
(xxx).l
4(1/0)
4(1/1)
4(1/1)
4(1/1)
—
—
(d16,PC)
4(1/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
—
—
(d8,PC,Xi*SF)
5(1/0)
5(1/1)
5(1/1)
5(1/1)
—
—
—
#
1(0/0)
2(0/1)
2(0/1)
2(0/1)
—
—
—
Table 2-11 lists timings for MOVE.L.
Table 2-11. Move Long Execution Times
Destination
Source
Rx
(Ax)
(Ax)+
-(Ax)
(d16,Ax)
(d8,Ax,Xi*SF)
(xxx).wl
Dy
1(0/0)
1(0/1)
1(0/1)
1(0/1)
1(0/1)
2(0/1)
1(0/1)
Ay
1(0/0)
1(0/1)
1(0/1)
1(0/1)
1(0/1)
2(0/1)
1(0/1)
(Ay)
3(1/0)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(1/1)
(Ay)+
3(1/0)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
3(1/1)
3(1/1)
-(Ay)
3(1/0)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
4(1/1)
(d16,Ay)
3(1/0)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
—
—
(d8,Ay,Xi*SF)
4(1/0)
4(1/1)
4(1/1)
4(1/1)
—
—
—
(xxx).w
3(1/0)
3(1/1)
3(1/1)
3(1/1)
—
—
—
(xxx).l
3(1/0)
3(1/1)
3(1/1)
3(1/1)
—
—
—
(d16,PC)
3(1/0)
3(1/1)
3(1/1)
3(1/1)
3(1/1)
—
—
(d8,PC,Xi*SF)
4(1/0)
4(1/1)
4(1/1)
4(1/1)
—
—
—
#
1(0/0)
2(0/1)
2(0/1)
2(0/1)
—
—
—
Table 2-12 gives execution times for MOVE.L instructions accessing program-visible
registers of the MAC unit, along with other MOVE.L timings. Execution times for moving
contents of the ACC or MACSR into a destination location represent the best-case scenario
when the store instruction is executed and there are no load or MAC or MSAC instruction
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Instruction Timing
in the MAC execution pipeline.
Table 2-12. MAC Move Execution Times
Effective Address
Freescale Semiconductor, Inc...
Opcode
Í
Rn
(An)
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#
move.l
,ACC
1(0/0)
—
—
—
—
—
—
1(0/0)
move.l
,MACSR
2(0/0)
—
—
—
—
—
—
2(0/0)
move.l
,MASK
1(0/0)
—
—
—
—
—
—
1(0/0)
move.l
ACC,Rx
3(0/0)
—
—
—
—
—
—
—
move.l
MACSR,CCR
3(0/0)
—
—
—
—
—
—
—
move.l
MACSR,Rx
3(0/0)
—
—
—
—
—
—
—
move.l
MASK,Rx
3(0/0)
—
—
—
—
—
—
—
2.7.2 Execution Timings—One-Operand Instructions
Table 2-13 shows standard timings for single-operand instructions.
Table 2-13. One-Operand Instruction Execution Times
Effective Address
Opcode
Í
Rn
(An)
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#xxx
clr.b
Í
1(0/0)
1(0/1)
1(0/1)
1(0/1)
1(0/1)
2(0/1)
1(0/1)
—
clr.w
Í
1(0/0)
1(0/1)
1(0/1)
1(0/1)
1(0/1)
2(0/1)
1(0/1)
—
clr.l
Í
1(0/0)
1(0/1)
1(0/1)
1(0/1)
1(0/1)
2(0/1)
1(0/1)
—
ext.w
Dx
1(0/0)
—
—
—
—
—
—
—
—
ext.l
Dx
1(0/0)
—
—
—
—
—
—
extb.l
Dx
1(0/0)
—
—
—
—
—
—
—
neg.l
Dx
1(0/0)
—
—
—
—
—
—
—
negx.l
Dx
1(0/0)
—
—
—
—
—
—
—
not.l
Dx
1(0/0)
—
—
—
—
—
—
—
scc
Dx
1(0/0)
—
—
—
—
—
—
—
swap
Dx
1(0/0)
—
—
—
—
—
—
—
tst.b
Í
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
1(0/0)
tst.w
Í
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
1(0/0)
tst.l
Í
1(0/0)
3(1/0)
3(1/0)
3(1/0)
3(1/0)
4(1/0)
3(1/0)
1(0/0)
2.7.3 Execution Timings—Two-Operand Instructions
Table 2-14 shows standard timings for two-operand instructions.
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Instruction Timing
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Table 2-14. Two-Operand Instruction Execution Times
Effective Address
Opcode
Freescale Semiconductor, Inc...
add.l
Í
,Rx
Rn
(An)
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
1(0/0)
add.l
Dy,
—
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
—
addi.l
#imm,Dx
1(0/0)
—
—
—
—
—
—
—
addq.l
#imm,
1(0/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
—
addx.l
Dy,Dx
1(0/0)
—
—
—
—
—
—
—
and.l
,Rx
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
1(0/0)
and.l
Dy,
—
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
—
andi.l
#imm,Dx
1(0/0)
—
—
—
—
—
—
—
asl.l
,Dx
1(0/0)
—
—
—
—
—
—
1(0/0)
asr.l
,Dx
1(0/0)
—
—
—
—
—
—
1(0/0)
bchg
Dy,
2(0/0)
5(1/1)
5(1/1)
5(1/1)
5(1/1)
6(1/1)
5(1/1)
—
bchg
#imm,
2(0/0)
5(1/1)
5(1/1)
5(1/1)
5(1/1)
—
—
—
bclr
Dy,
2(0/0)
5(1/1)
5(1/1)
5(1/1)
5(1/1)
6(1/1)
5(1/1)
—
—
bclr
#imm,
2(0/0)
5(1/1)
5(1/1)
5(1/1)
5(1/1)
—
—
bset
Dy,
2(0/0)
5(1/1)
5(1/1)
5(1/1)
5(1/1)
6(1/1)
5(1/1)
—
bset
#imm,
2(0/0)
5(1/1)
5(1/1)
5(1/1)
5(1/1)
—
—
—
btst
Dy,
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
—
btst
#imm,
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
—
—
—
1(0/0)
cmp.l
,Rx
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
cmpi.l
#imm,Dx
1(0/0)
—
—
—
—
—
—
—
divs.w
,Dx
20(0/0)
23(1/0)
23(1/0)
23(1/0)
23(1/0)
24(1/0)
23(1/0)
20(0/0)
divu.w
,Dx
20(0/0)
23(1/0)
23(1/0)
23(1/0)
23(1/0)
24(1/0)
23(1/0)
20(0/0)
divs.l
,Dx
35(0/0)
35(1/0)
35(1/0)
35(1/0)
35(1/0)
—
—
—
divu.l
,Dx
35(0/0)
35(1/0)
35(1/0)
35(1/0)
35(1/0)
—
—
—
eor.l
Dy,
1(0/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
—
eori.l
#imm,Dx
1(0/0)
—
—
—
—
—
—
—
lea
,Ax
—
1(0/0)
—
—
1(0/0)
2(0/0)
1(0/0)
—
lsl.l
,Dx
1(0/0)
—
—
—
—
—
—
1(0/0)
lsr.l
,Dx
1(0/0)
—
—
—
—
—
—
1(0/0)
mac.w
Ry,Rx
1(0/0)
—
—
—
—
—
—
—
mac.l
Ry,Rx
3(0/0)
—
—
—
—
—
—
—
msac.w
Ry,Rx
1(0/0)
—
—
—
—
—
—
—
msac.l
Ry,Rx
3(0/0)
—
—
—
—
—
—
—
mac.w
Ry,Rx,ea,Rw
—
3(1/0)
3(1/0)
3(1/0)
3(1/0)
—
—
—
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Instruction Timing
Table 2-14. Two-Operand Instruction Execution Times (Continued)
Effective Address
Freescale Semiconductor, Inc...
Opcode
Í
Rn
(An)
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#
mac.l
Ry,Rx,ea,Rw
—
5(1/0)
5(1/0)
5(1/0)
5(1/0)
—
—
—
moveq
#imm,Dx
—
—
—
—
—
—
—
1(0/0)
msac.w
Ry,Rx,ea,Rw
—
3(1/0)
3(1/0)
3(1/0)
3(1/0)
—
—
—
msac.l
Ry,Rx,ea,Rw
—
5(1/0)
5(1/0)
5(1/0)
5(1/0)
—
—
—
muls.w
,Dx
3(0/0)
6(1/0)
6(1/0)
6(1/0)
6(1/0)
7(1/0)
6(1/0)
3(0/0)
mulu.w
,Dx
3(0/0)
6(1/0)
6(1/0)
6(1/0)
6(1/0)
7(1/0)
6(1/0)
3(0/0)
muls.l
,Dx
5(0/0)
8(1/0)
8(1/0)
8(1/0)
8(1/0)
—
—
—
mulu.l
,Dx
5(0/0)
8(1/0)
8(1/0)
8(1/0)
8(1/0)
—
—
—
or.l
,Rx
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
1(0/0)
or.l
Dy,
—
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
—
or.l
#imm,Dx
1(0/0)
—
—
—
—
—
—
—
rems.l
,Dx
35(0/0)
35(1/0)
35(1/0)
35(1/0)
35(1/0)
—
—
—
remu.l
,Dx
35(0/0)
35(1/0)
35(1/0)
35(1/0)
35(1/0)
—
—
—
sub.l
,Rx
1(0/0)
4(1/0)
4(1/0)
4(1/0)
4(1/0)
5(1/0)
4(1/0)
1(0/0)
sub.l
Dy,
—
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
—
subi.l
#imm,Dx
1(0/0)
—
—
—
—
—
—
—
subq.l
#imm,
1(0/0)
4(1/1)
4(1/1)
4(1/1)
4(1/1)
5(1/1)
4(1/1)
—
subx.l
Dy,Dx
1(0/0)
—
—
—
—
—
—
—
2.7.4 Miscellaneous Instruction Execution Times
Table 2-15 lists timings for miscellaneous instructions.
Table 2-15. Miscellaneous Instruction Execution Times
Effective Address
Opcode
Í
cpushl
(Ax)
Rn
(An)
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#
—
11(0/1)
—
—
—
—
—
—
link.w
Ay,#imm
2(0/1)
—
—
—
—
—
—
—
move.w
CCR,Dx
1(0/0)
—
—
—
—
—
—
—
move.w
,CCR
1(0/0)
—
—
—
—
—
—
1(0/0)
move.w
SR,Dx
1(0/0)
—
—
—
—
—
—
—
move.w
,SR
9(0/0)
—
—
—
—
—
—
9(0/0)1
movec
Ry,Rc
11(0/1)
—
—
—
—
—
—
—
movem.l 2
,&list
—
2+n(n/0)
—
—
2+n(n/0)
—
—
—
movem.l
&list,
—
2+n(0/n)
—
—
2+n(0/n)
—
—
—
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Instruction Timing
Table 2-15. Miscellaneous Instruction Execution Times (Continued)
Effective Address
Opcode
Í
Rn
nop
3(0/0)
pea
Í
—
pulse
Freescale Semiconductor, Inc...
(An)
stop
#imm
trap
#imm
(An)+
—
-(An)
—
2(0/1)
—
(d16,An)
—
—
(d8,An,Xi*SF)
—
3
2(0/1)
(xxx).wl
#
—
—
—
3(0/1)4
2(0/1)
—
1(0/0)
—
—
—
—
—
—
—
—
—
—
—
—
—
—
3(0/0)5
—
—
—
—
—
—
—
18(1/2)
trapf
1(0/0)
—
—
—
—
—
—
—
trapf.w
1(0/0)
—
—
—
—
—
—
—
trapf.l
unlk
Ax
1(0/0)
—
—
—
—
—
—
—
3(1/0)
—
—
—
—
—
—
—
wddata.l
Í
—
7(1/0)
7(1/0)
7(1/0)
7(1/0)
8(1/0)
7(1/0)
—
wdebug.l
Í
—
10(2/0)
—
—
10(2/0)
—
—
—
1
If a MOVE.W #imm,SR instruction is executed and #imm[13] = 1, the execution time is 1(0/0).
n is the number of registers moved by the MOVEM opcode.
3 PEA execution times are the same for (d16,PC).
4 PEA execution times are the same for (d8,PC,Xi*SF).
5 The execution time for STOP is the time required until the processor begins sampling continuously for
interrupts.
2
2.7.5 Branch Instruction Execution Times
Table 2-16 shows general branch instruction timing.
Table 2-16. General Branch Instruction Execution Times
Effective Address
Opcode
Í
Rn
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#
—
—
—
—
—
—
6(0/0)
1(0/0)1
—
1
—
bra
—
—
—
—
1(0/1)1
bsr
—
—
—
—
1(0/1)1
jmp
jsr
1
(An)
Í
Í
—
5(0/0)
—
—
5(0/1)
—
—
1
5(0/0)
—
5(0/1)
6(0/1)
1(0/1)
rte
—
—
14(2/0)
—
—
—
—
—
rts
—
—
8(1/0)
—
—
—
—
—
Assumes branch acceleration. Depending on the pipeline status, execution times may vary from 1 to 3 cycles.
For the conditional branch opcodes (bcc), a static algorithm is used to determine the
prediction state of the branch. This algorithm is:
if bcc is a forward branch && CCR[7] == 0
then the bcc is predicted as not-taken
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if bcc is a forward branch && CCR[7] == 1
then the bcc is predicted as taken
else if bcc is a backward branch
then the bcc is predicted as taken
Table 2-17 shows timing for Bcc instructions.
Freescale Semiconductor, Inc...
Table 2-17. Bcc Instruction Execution Times
Opcode
Predicted
Correctly as Taken
Predicted
Correctly as Not
Taken
Predicted
Incorrectly
bcc
1(0/0)
1(0/0)
5(0/0)
2.8 Exception Processing Overview
Exception processing for ColdFire processors is streamlined for performance. Differences
from previous M68000 Family processors include the following:
•
•
•
•
A simplified exception vector table
Reduced relocation capabilities using the vector base register
A single exception stack frame format
Use of a single, self-aligning system stack pointer
ColdFire processors use an instruction restart exception model but require more software
support to recover from certain access errors. See Table 2-18 for details.
Exception processing can be defined as the time from the detection of the fault condition
until the fetch of the first handler instruction has been initiated. It is comprised of the
following four major steps:
1. The processor makes an internal copy of the SR and then enters supervisor mode by
setting SR[S] and disabling trace mode by clearing SR[T]. The occurrence of an
interrupt exception also forces SR[M] to be cleared and the interrupt priority mask
to be set to the level of the current interrupt request.
2. The processor determines the exception vector number. For all faults except
interrupts, the processor performs this calculation based on the exception type. For
interrupts, the processor performs an interrupt-acknowledge (IACK) bus cycle to
obtain the vector number from a peripheral device. The IACK cycle is mapped to a
special acknowledge address space with the interrupt level encoded in the address.
3. The processor saves the current context by creating an exception stack frame on the
system stack. ColdFire processors support a single stack pointer in the A7 address
register; therefore, there is no notion of separate supervisor and user stack pointers.
As a result, the exception stack frame is created at a 0-modulo-4 address on the top
of the current system stack. Additionally, the processor uses a simplified
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Exception Processing Overview
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fixed-length stack frame for all exceptions. The exception type determines whether
the program counter in the exception stack frame defines the address of the faulting
instruction (fault) or of the next instruction to be executed (next).
4. The processor acquires the address of the first instruction of the exception handler.
The exception vector table is aligned on a 1-Mbyte boundary. This instruction
address is obtained by fetching a value from the table at the address defined in the
vector base register. The index into the exception table is calculated as
4 x vector_number. When the index value is generated, the vector table contents
determine the address of the first instruction of the desired handler. After the fetch
of the first opcode of the handler is initiated, exception processing terminates and
normal instruction processing continues in the handler.
ColdFire processors support a 1024-byte vector table aligned on any 1-Mbyte address
boundary; see Table 2-18. The table contains 256 exception vectors where the first 64 are
defined by Motorola; the remaining 192 are user-defined interrupt vectors.
Table 2-18. Exception Vector Assignments
Vector Numbers
Vector Offset (Hex)
Stacked Program Counter 1
0
000
—
Initial stack pointer
1
004
—
Initial program counter
2
008
Fault
Access error
3
00C
Fault
Address error
4
010
Fault
Illegal instruction
2-48
Assignment
5
014
Fault
6–7
018–01C
—
Divide by zero
8
020
Fault
Privilege violation
Reserved
9
024
Next
Trace
10
028
Fault
Unimplemented line-a opcode
11
02C
Fault
Unimplemented line-f opcode
12
030
Next
Debug interrupt
13
034
—
14
038
Fault
Format error
15
03C
Next
Uninitialized interrupt
16–23
040–05C
—
24
060
Next
Spurious interrupt
25–31
064–07C
Next
Level 1–7 autovectored interrupts
32–47
080–0BC
Next
48–60
0C0–0F0
—
61
0F4
Fault
Reserved
Reserved
Trap #0–15 instructions
Reserved
Unsupported instruction
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Exception Processing Overview
Table 2-18. Exception Vector Assignments (Continued)
Stacked Program Counter 1
Vector Numbers
Vector Offset (Hex)
62–63
0F8–0FC
—
64–255
100–3FC
Next
1
Assignment
Reserved
User-defined interrupts
The term ‘fault’ refers to the PC of the instruction that caused the exception. The term ‘next’ refers to the PC
of the instruction that immediately follows the instruction that caused the fault.
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ColdFire processors inhibit sampling for interrupts during the first instruction of all
exception handlers. This allows any handler to effectively disable interrupts, if necessary,
by raising the interrupt mask level contained in the status register.
2.8.1 Exception Stack Frame Definition
The exception stack frame is shown in Figure 2-10. The first longword of the exception
stack frame contains the 16-bit format/vector word (F/V) and the 16-bit status register. The
second longword contains the 32-bit program counter address.
31
A7→
28
Format
27
26
25
FS[3–2]
+ 0x04
18
Vector[7–0]
17
16
15
0
FS[1–0]
Status Register
Program Counter [31–0]
Figure 2-10. Exception Stack Frame Form
The 16-bit format/vector word contains three unique fields:
•
Format field—This 4-bit field at the top of the system stack is always written with a
value of {4,5,6,7} by the processor indicating a 2-longword frame format. See
Table 2-19. This field records any longword misalignment of the stack pointer that
may have existed when the exception occurred.
Table 2-19. Format Field Encoding
•
Original A7 at Time of
Exception, Bits 1–0
A7 at First Instruction of
Handler
Format Field Bits
31–28
00
Original A[7–8]
0100
01
Original A[7–9]
0101
10
Original A[7–10]
0110
11
Original A[7–11]
0111
Fault status field—The 4-bit field, FS[3–0], at the top of the system stack is defined
for access and address errors along with interrupted debug service routines. See
Table 2-20.
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Table 2-20. Fault Status Encodings
FS[3–0]
0000
0001-001x
0100
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0101–011x
Not an access or address error
Reserved
Error on instruction fetch
Reserved
1000
Error on operand write
1001
Attempted write to write-protected space
101x
Reserved
1100
Error on operand read
1101–111x
•
Definition
Reserved
Vector number—This 8-bit field, vector[7–0], defines the exception type. It is
calculated by the processor for internal faults and is supplied by the peripheral for
interrupts. See Table 2-18.
2.8.2 Processor Exceptions
Table 2-21 describes MCF5307 exceptions.
Table 2-21. MCF5307 Exceptions
Exception
Description
Access Error
Access errors are reported only in conjunction with an attempted store to write-protected memory.
Thus, access errors associated with instruction fetch or operand read accesses are not possible.
Address
Error
Caused by an attempted execution transferring control to an odd instruction address (that is, if bit 0 of
the target address is set), an attempted use of a word-sized index register (Xi.w) or a scale factor of
8 on an indexed effective addressing mode, or attempted execution of an instruction with a full-format
indexed addressing mode.
Illegal
Instruction
On Version 2 ColdFire implementations, only some illegal opcodes were decoded and generated an
illegal instruction exception. The Version 3 processor decodes the full 16-bit opcode and generates
this exception if execution of an unsupported instruction is attempted. Additionally, attempting to
execute an illegal line A or line F opcode generates unique exception types: vectors 10 and 11,
respectively.
ColdFire processors do not provide illegal instruction detection on extension words of any instruction,
including MOVEC. Attempting to execute an instruction with an illegal extension word causes
undefined results.
Divide by
Zero
Attempted division by zero causes an exception (vector 5, offset = 0x014) except when the PC points
to the faulting instruction (DIVU, DIVS, REMU, REMS).
Privilege
Violation
Caused by attempted execution of a supervisor mode instruction while in user mode. The ColdFire
Programmer’s Reference Manual lists supervisor- and user-mode instructions.
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Table 2-21. MCF5307 Exceptions (Continued)
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Exception
Description
Trace
Exception
ColdFire processors provide instruction-by-instruction tracing. While the processor is in trace mode
(SR[T] = 1), instruction completion signals a trace exception. This allows a debugger to monitor
program execution.
The only exception to this definition is the STOP instruction. If the processor is in trace mode, the
instruction before the STOP executes and then generates a trace exception. In the exception stack
frame, the PC points to the STOP opcode. When the trace handler is exited, the STOP instruction is
executed, loading the SR with the immediate operand from the instruction. The processor then
generates a trace exception. The PC in the exception stack frame points to the instruction after
STOP, and the SR reflects the just-loaded value.
If the processor is not in trace mode and executes a STOP instruction where the immediate operand
sets the trace bit in the SR, hardware loads the SR and generates a trace exception. The PC in the
exception stack frame points to the instruction after STOP, and the SR reflects the just-loaded value.
Because ColdFire processors do not support hardware stacking of multiple exceptions, it is the
responsibility of the operating system to check for trace mode after processing other exception types.
As an example, consider a TRAP instruction executing in trace mode. The processor initiates the
TRAP exception and passes control to the corresponding handler. If the system requires that a trace
exception be processed, the TRAP exception handler must check for this condition (SR[15] in the
exception stack frame asserted) and pass control to the trace handler before returning from the
original exception.
Debug
Interrupt
Caused by a hardware breakpoint register trigger. Rather than generating an IACK cycle, the
processor internally calculates the vector number (12). Additionally, the M bit and the interrupt priority
mask fields of the SR are unaffected by the interrupt. See Section 2.2.2.1, “Status Register (SR).”
RTE and
Format Error
Exceptions
When an RTE instruction executes, the processor first examines the 4-bit format field to validate the
frame type. For a ColdFire processor, any attempted execution of an RTE where the format is not
equal to {4,5,6,7} generates a format error. The exception stack frame for the format error is created
without disturbing the original exception frame and the stacked PC points to RTE.The selection of the
format value provides limited debug support for porting code from M68000 applications. On M68000
Family processors, the SR was at the top of the stack. Bit 30 of the longword addressed by the
system stack pointer is typically zero; so, attempting an RTE using this old format generates a format
error on a ColdFire processor.
If the format field defines a valid type, the processor does the following:
1 Reloads the SR operand.
2 Fetches the second longword operand.
3 Adjusts the stack pointer by adding the format value to the auto-incremented address after the first
longword fetch.
4 Transfers control to the instruction address defined by the second longword operand in the stack
frame.
TRAP
Executing TRAP always forces an exception and is useful for implementing system calls. The trap
instruction may be used to change from user to supervisor mode.
Interrupt
Exception
Interrupt exception processing, with interrupt recognition and vector fetching, includes uninitialized
and spurious interrupts as well as those where the requesting device supplies the 8-bit interrupt
vector. Autovectoring may optionally be configured through the system interface module (SIM). See
Section 9.2.2, “Autovector Register (AVR).”
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Exception Processing Overview
Table 2-21. MCF5307 Exceptions (Continued)
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Exception
Description
Reset
Exception
Asserting the reset input signal (RSTI) causes a reset exception. Reset has the highest exception
priority; it provides for system initialization and recovery from catastrophic failure. When assertion of
RSTI is recognized, current processing is aborted and cannot be recovered. The reset exception
places the processor in supervisor mode by setting SR[S] and disables tracing by clearing SR[T].
This exception also clears SR[M] and sets the processor’s interrupt priority mask in the SR to the
highest level (level 7). Next, the VBR is initialized to 0x0000_0000. Configuration registers controlling
the operation of all processor-local memories (cache and RAM modules on the MCF5307) are
invalidated, disabling the memories.
Note: Other implementation-specific supervisor registers are also affected. Refer to each of the
modules in this manual for details on these registers.
After RSTI is negated, the processor waits 80 cycles before beginning the actual reset exception
process. During this time, certain events are sampled, including the assertion of the debug
breakpoint signal. If the processor is not halted, it initiates the reset exception by performing two
longword read bus cycles. The longword at address 0 is loaded into the stack pointer and the
longword at address 4 is loaded into the PC. After the initial instruction is fetched from memory,
program execution begins at the address in the PC. If an access error or address error occurs before
the first instruction executes, the processor enters the fault-on-fault halted state.
Unsupported
Instruction
Exception
If the MCF5307 attempts to execute a valid instruction but the required optional hardware module is
not present in the OEP, a non-supported instruction exception is generated (vector 0x61). Control is
then passed to an exception handler that can then process the opcode as required by the system.
If a ColdFire processor encounters any type of fault during the exception processing of
another fault, the processor immediately halts execution with the catastrophic fault-on-fault
condition. A reset is required to force the processor to exit this halted state.
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Chapter 3
Hardware Multiply/Accumulate (MAC)
Unit
This chapter describes the MCF5307 multiply/accumulate (MAC) unit, which executes
integer multiply, multiply-accumulate, and miscellaneous register instructions. The MAC
is integrated into the operand execution pipeline (OEP).
3.1 Overview
The MAC unit provides hardware support for a limited set of digital signal processing
(DSP) operations used in embedded code, while supporting the integer multiply
instructions in the ColdFire microprocessor family.
The MAC unit provides signal processing capabilities for the MCF5307 in a variety of
applications including digital audio and servo control. Integrated as an execution unit in the
processor’s OEP, the MAC unit implements a three-stage arithmetic pipeline optimized for
16 x 16 multiplies. Both 16- and 32-bit input operands are supported by this design in
addition to a full set of extensions for signed and unsigned integers plus signed, fixed-point
fractional input operands.
The MAC unit provides functionality in three related areas:
•
•
•
Signed and unsigned integer multiplies
Multiply-accumulate operations supporting signed, unsigned, and signed fractional
operands
Miscellaneous register operations
Each of the three areas of support is addressed in detail in the succeeding sections. Logic
that supports this functionality is contained in a MAC module, as shown in Figure 3-1.
The MAC unit is tightly coupled to the OEP and features a three-stage execution pipeline.
To minimize silicon costs, the ColdFire MAC is optimized for 16 x 16 multiply
instructions. The OEP can issue a 16 x 16 multiply with a 32-bit accumulation and fetch a
32-bit operand in the same cycle. A 32 x 32 multiply with a 32-bit accumulation takes three
cycles before the next instruction can be issued. Figure 3-1 shows the basic functionality of
the ColdFire MAC. A full set of instructions is provided for signed and unsigned integers
plus signed, fixed-point, fractional input operands.
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Operand Y
Operand X
X
Shift 0,1,-1
+/-
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Accumulator
Figure 3-1. ColdFire MAC Multiplication and Accumulation
The MAC unit is an extension of the basic multiplier found on most microprocessors. It can
perform operations native to signal processing algorithms in an acceptable number of
cycles, given the application constraints. For example, small digital filters can tolerate some
variance in the execution time of the algorithm; larger, more complicated algorithms such
as orthogonal transforms may have more demanding speed requirements exceeding the
scope of any processor architecture and requiring a fully developed DSP implementation.
The M68000 architecture was not designed for high-speed signal processing, and a large
DSP engine would be excessive in an embedded environment. In striking a middle ground
between speed, size, and functionality, the ColdFire MAC unit is optimized for a small set
of operations that involve multiplication and cumulative additions. Specifically, the
multiplier array is optimized for single-cycle, 16 x 16 multiplies producing a 32-bit result,
with a possible accumulation cycle following. This is common in a large portion of signal
processing applications. In addition, the ColdFire core architecture has been modified to
allow for an operand fetch in parallel with a multiply, increasing overall performance for
certain DSP operations.
3.1.1 MAC Programming Model
Figure 3-2 shows the registers in the MAC portion of the user programming model.
31
0
MACSR
ACC
MASK
MAC status register
MAC accumulator
MAC mask register
Figure 3-2. MAC Programming Model
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Overview
These registers are described as follows:
•
•
Freescale Semiconductor, Inc...
•
Accumulator (ACC)—This 32-bit, read/write, general-purpose register is used to
accumulate the results of MAC operations.
Mask register (MASK)—This 16-bit general-purpose register provides an optional
address mask for MAC instructions that fetch operands from memory. It is useful in
the implementation of circular queues in operand memory.
MAC status register (MACSR)—This 8-bit register defines configuration of the
MAC unit and contains indicator flags affected by MAC instructions. Unless noted
otherwise, the setting of MACSR indicator flags is based on the final result, that is,
the result of the final operation involving the product and accumulator.
3.1.2 General Operation
The MAC unit supports the ColdFire integer multiply instructions (MULS and MULU) and
provides additional functionality for multiply-accumulate operations. The added MAC
instructions to the ColdFire ISA provide for the multiplication of two numbers, followed
by the addition or subtraction of this number to or from the value contained in the
accumulator. The product may be optionally shifted left or right one bit before the addition
or subtraction takes place. Hardware support for saturation arithmetic may be enabled to
minimize software overhead when dealing with potential overflow conditions using signed
or unsigned operands.
These MAC operations treat the operands as one of the following formats:
•
•
•
Signed integers
Unsigned integers
Signed, fixed-point, fractional numbers
To maintain compactness, the MAC module is optimized for 16-bit multiplications. Two
16-bit operands produce a 32-bit product. Longword operations are performed by reusing
the 16-bit multiplier array at the expense of a small amount of extra control logic. Again,
the product of two 32-bit operands is a 32-bit result. For longword integer operations, only
the least significant 32 bits of the product are calculated. For fractional operations, the
entire 63-bit product is calculated and then either truncated or rounded to a 32-bit result
using the round-to-nearest (even) method.
Because the multiplier array is implemented in a 3-stage pipeline, MAC instructions can
have an effective issue rate of one clock for word operations, three for longword integer
operations, and four for 32-bit fractional operations. Arithmetic operations use
register-based input operands, and summed values are stored internally in the accumulator.
Thus, an additional MOVE instruction is necessary to store data in a general-purpose
register. MAC instructions can choose the upper or lower word of a register as the input,
which helps filtering operations in which one data register is loaded with input data and
another is loaded with coefficient data. Two 16-bit MAC operations can be performed
without fetching additional operands between instructions by alternating the word choice
Chapter 3. Hardware Multiply/Accumulate (MAC) Unit
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Overview
during the calculations.
The need to move large amounts of data quickly can limit throughput in DSP engines.
However, data can be moved efficiently by using the MOVEM instruction, which
automatically generates line-sized burst references and is ideal for filling registers quickly
with input data, filter coefficients, and output data. Loading an operand from memory into
a register during a MAC operation makes some DSP operations, especially filtering and
convolution, more manageable.
Freescale Semiconductor, Inc...
The MACSR has a 4-bit operational mode field and three condition flags. The operational
mode bits control the overflow/saturation mode, whether operands are signed or unsigned,
whether operands are treated as integers or fractions, and how rounding is performed.
Negative, zero and overflow flags are also provided.
The three program-visible MAC registers, a 32-bit accumulator (ACC), the MAC mask
register (MASK), and MACSR, are described in Section 3.1.1, “MAC Programming
Model.”
3.1.3 MAC Instruction Set Summary
The MAC unit supports the integer multiply operations defined by the baseline ColdFire
architecture, as well as the new multiply-accumulate instructions. Table 3-1 summarizes
the MAC unit instruction set.
Table 3-1. MAC Instruction Summary
Instruction
Mnemonic
Description
Multiply Signed
MULS y,Dx
Multiply Unsigned
MULU y,Dx
Multiplies two signed operands yielding a signed result
Multiplies two unsigned operands yielding an unsigned result
Multiply Accumulate
MAC Ry,RxSF
MSAC Ry,RxSF
Multiplies two operands, then adds or subtracts the product
to/from the accumulator
Multiply Accumulate
with Load
MAC Ry,RxSF,Rw
MSAC Ry,RxSF,Rw
Multiplies two operands, then adds or subtracts the product
to/from the accumulator while loading a register with the
memory operand
Load Accumulator
MOV.L {Ry,#imm},ACC
Loads the accumulator with a 32-bit operand
Store Accumulator
MOV.L ACC,Rx
Writes the contents of the accumulator to a register
Load MACSR
MOV.L {Ry,#imm},MACSR Writes a value to the MACSR
Store MACSR
MOV.L MACSR,Rx
Write the contents of MACSR to a register
Store MACSR to CCR
MOV.L MACSR,CCR
Write the contents of MACSR to the processor’s CCR register
Load MASK
MOV.L {Ry,#imm},MASK
Writes a value to MASK
Store MASK
MOV.L MASK,Rx
Writes the contents of MASK to a register
3.1.4 Data Representation
The MAC unit supports three basic operand types:
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MAC Instruction Execution Timings
•
•
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•
Two’s complement signed integer: In this format, an N-bit operand represents a
number within the range -2(N-1) < operand < 2(N-1) - 1. The binary point is to the right
of the least significant bit.
Two’s complement unsigned integer: In this format, an N-bit operand represents a
number within the range 0 < operand < 2N - 1. The binary point is to the right of the
least significant bit.
Two’s complement, signed fractional: In an N-bit number, the first bit is the sign bit.
The remaining bits signify the first N-1 bits after the binary point. Given an N-bit
number, aN-1aN-2aN-3... a2a1a0, its value is given by the following formula:
N–2
+
∑2
(i + 1 – N)
⋅ ai
i=0
This format can represent numbers in the range -1 < operand < 1 - 2(N-1).
For words and longwords, the greatest negative number that can be represented is -1,
whose internal representation is 0x8000 and 0x0x8000_0000, respectively. The
most positive word is 0x7FFF or (1 - 2-15); the most positive longword is
0x7FFF_FFFF or (1 - 2-31).
3.2 MAC Instruction Execution Timings
Table 3-2 shows standard timings for two-operand MAC instructions.
Table 3-2. Two-Operand MAC Instruction Execution Times
Effective Address
Opcode
Í
Rn
(An)
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#
mac.w
Ry,Rx
1(0/0)
—
—
—
—
—
—
—
mac.l
Ry,Rx
3(0/0)
—
—
—
—
—
—
—
msac.w
Ry,Rx
1(0/0)
—
—
—
—
—
—
—
msac.l
Ry,Rx
3(0/0)
—
—
—
—
—
—
—
mac.w
Ry,Rx,ea,Rw
—
1(1/0)
1(1/0)
1(1/0)
1(1/0)
—
—
—
mac.l
Ry,Rx,ea,Rw
—
3(1/0)
3(1/0)
3(1/0)
3(1/0)
—
—
—
msac.w
Ry,Rx,ea,Rw
—
1(1/0)
1(1/0)
1(1/0)
1(1/0)
—
—
—
msac.l
Ry,Rx,ea,Rw
—
3(1/0)
3(1/0)
3(1/0)
3(1/0)
—
—
—
muls.w
,Dx
3(0/0)
3(1/0)
3(1/0)
3(1/0)
3(1/0)
4(1/0)
3(1/0)
3(0/0)
mulu.w
,Dx
3(0/0)
3(1/0)
3(1/0)
3(1/0)
3(1/0)
4(1/0)
3(1/0)
3(0/0)
muls.l
,Dx
5(0/0)
5(1/0)
5(1/0)
5(1/0)
5(1/0)
—
—
—
mulu.l
,Dx
5(0/0)
5(1/0)
5(1/0)
5(1/0)
5(1/0)
—
—
—
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MAC Instruction Execution Timings
Table 3-3 shows standard timings for MAC move instructions.
Table 3-3. MAC Move Instruction Execution Times
Effective Address
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Opcode
Í
Rn
(An)
(An)+
-(An)
(d16,An)
(d8,An,Xi*SF)
(xxx).wl
#
move.l
,ACC
1(0/0)
—
—
—
—
—
—
1(0/0)
move.l
,MACSR
6(0/0)
—
—
—
—
—
—
6(0/0)
move.l
,MASK
5(0/0)
—
—
—
—
—
—
5(0/0)
move.l
ACC,Rx
1(0/0)
—
—
—
—
—
—
—
move.l
MACSR,CCR
1(0/0)
—
—
—
—
—
—
—
move.l
MACSR,Rx
1(0/0)
—
—
—
—
—
—
—
move.l
MASK,Rx
1(0/0)
—
—
—
—
—
—
—
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Chapter 4
Local Memory
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This chapter describes the MCF5307 implementation of the ColdFire Version 3 local
memory specification. It consists of two major sections.
•
•
Section 4.2, “SRAM Overview,” describes the MCF5307 on-chip static RAM
(SRAM) implementation. It covers general operations, configuration, and
initialization. It also provides information and examples showing how to minimize
power consumption when using the SRAM.
Section 4.7, “Cache Overview,” describes the MCF5307 cache implementation,
including organization, configuration, and coherency. It describes cache operations
and how the cache interfaces with other memory structures.
4.1 Interactions between Local Memory Modules
Depending on configuration information, instruction fetches and data read accesses may be
sent simultaneously to the RAM and cache controllers. This approach is required because
both controllers are memory-mapped devices and the hit/miss determination is made
concurrently with the read data access. Power dissipation can be minimized by configuring
the RAMBARs to mask unused address spaces whenever possible.
If the access address is mapped into the region defined by the RAM (and this region is not
masked), the RAM provides the data back to the processor, and the cache data is discarded.
Accesses from the RAM module are never cached. The complete definition of the
processor’s local bus priority scheme for read references is as follows:
)
if (RAM “hits”
RAM supplies data to the processor
else if (cache “hits”)
cache supplies data to the processor
else system memory reference to access data
For data write references, the memory mapping into the local memories is resolved before
the appropriate destination memory is accessed. Accordingly, only the targeted local
memory is accessed for data write transfers.
4.2 SRAM Overview
The 4-Kbyte on-chip SRAM module is connected to the internal bus and provides pipelined,
single-cycle access to memory mapped to the module. Memory can be mapped to any
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SRAM Operation
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0-modulo-32K location in the 4-Gbyte address space and configured to respond to either
instruction or data accesses.Time-critical functions can be mapped into instruction the
system stack. Other heavily-referenced data can be mapped into memory.
The following summarizes features of the MCF5307 SRAM implementation:
Freescale Semiconductor, Inc...
•
•
•
•
•
•
4-Kbyte SRAM, organized as 1024 x 32 bits
Single-cycle throughput. When the pipeline is full, one access can occur per clock
cycle.
Physical location on the processor’s high-speed local bus
Memory location programmable on any 0-modulo-32K address boundary
Byte, word, and longword address capabilities
The RAM base address register (RAMBAR) defines the logical base address,
attributes, and access types for the SRAM module.
4.3 SRAM Operation
The SRAM module provides a general-purpose memory block that the ColdFire processor
can access with single-cycle throughput. The location of the memory block can be specified
to any word-aligned address in the 4-Gbyte address space by RAMBAR[BA], described in
Section 4.4.1, “SRAM Base Address Register (RAMBAR).” The memory is ideal for
storing critical code or data structures or for use as the system stack. Because the SRAM
module connects physically to the processor’s high-speed local bus, it can service
processor-initiated accesses or memory-referencing debug module commands.
Instruction fetches and data reads can be sent to both the cache and SRAM blocks
simultaneously. If the reference is mapped into a region defined by the SRAM, the SRAM
provides data to the processor and any cache data is discarded. Data accessed from the
SRAM module are not cached.
Note also that the SRAM cannot be accessed by the on-chip DMAs. The on-chip system
configuration allows concurrent core and DMA execution, where the core can reference
code or data from the internal SRAM or cache while performing a DMA transfer.
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SRAM Programming Model
Accesses are attempted in the following order:
1. SRAM
2. Cache (if space is defined as cacheable)
3. External access
4.4 SRAM Programming Model
The SRAM programming model consists of RAMBAR.
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4.4.1 SRAM Base Address Register (RAMBAR)
The SRAM modules are configured through the RAMBAR, shown in Figure 4-1.
•
•
•
•
RAMBAR holds the base address of the SRAM. The MOVEC instruction provides
write-only access to this register from the processor.
RAMBAR can be read or written from the debug module in a similar manner.
All undefined RAMBAR bits are reserved. These bits are ignored during writes to
the RAMBAR and return zeros when read from the debug module.
The valid bit, RAMBAR[V], is cleared at reset, disabling the SRAM module. All
other bits are unaffected.
31
Field
15
BA
14
9
—
Reset
8
WP
7
6
—
5
4
3
2
1
0
C/I SC SD UC UD
V
—
R/W
0
W for CPU; R/W for debug
Address
CPU space + 0xC04
Figure 4-1. SRAM Base Address Register (RAMBAR)
RAMBAR fields are described in detail in Table 4-1.
Table 4-1. RAMBAR Field Description
Bits
Name
Description
31–15 BA
Base address. Defines the SRAM module’s word-aligned base address. The SRAM module
occupies a 4-Kbyte space defined by the contents of BA. SRAM may reside on any 32-Kbyte
boundary in the 4-Gbyte address space.
14–9
—
Reserved, should be cleared.
8
WP
Write protect. Controls read/write properties of the SRAM.
0 Allows read and write accesses to the SRAM module
1 Allows only read accesses to the SRAM module. Any attempted write reference generates an
access error exception to the ColdFire processor core.
7–6
—
Reserved, should be cleared.
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SRAM Initialization
Table 4-1. RAMBAR Field Description (Continued)
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Bits
Name
Description
5–1
C/I,
SC,
SD,
UC,
UD
Address space masks (ASn). These fields allow certain types of accesses to be masked, or
inhibited from accessing the SRAM module. These bits are useful for power management as
described in Section 4.6, “Power Management.” In particular, C/I is typically set.
The address space mask bits are follows:
C/I = CPU space/interrupt acknowledge cycle mask. Note that C/I must be set if BA = 0.
SC = Supervisor code address space mask
SD = Supervisor data address space mask
UC = User code address space mask
UD = User data address space mask
For each ASn bit:
0 An access to the SRAM module can occur for this address space
1 Disable this address space from the SRAM module. If a reference using this address space is
made, it is inhibited from accessing the SRAM module and is processed like any other
non-SRAM reference.
0
V
Valid. Enables/disables the SRAM module. V is cleared at reset.
0 RAMBAR contents are not valid.
1 RAMBAR contents are valid.
The mapping of a given access into the RAM uses the following algorithm to determine if
the access hits in the memory:
if (RAMBAR[0] = 1)
if (requested address[31:15] = RAMBAR[31:15])
if (requested address[14:12] = 0)
if (ASn of the requested type = 0)
Access is mapped to the RAM module
if (access = read)
Read the RAM and return the data
if (access = write)
if (RAMBAR[8] = 0)
Write the data into the RAM
else Signal a write-protect access error
ASn refers to the five address space mask bits: C/I, SC, SD, UC, and UD.
4.5 SRAM Initialization
After a hardware reset, the contents of the SRAM module are undefined. The valid bit,
RAMBAR[V], is cleared, disabling the SRAM module. If the SRAM requires initialization
with instructions or data, the following steps should be performed:
1. Read the source data and write it to the SRAM. Various instructions support this
function, including memory-to-memory move instructions and the move multiple
instruction (MOVEM). MOVEM is optimized to generate line-sized burst fetches on
line-aligned addresses, so it generally provides maximum performance.
2. After the data is loaded into the SRAM, it may be appropriate to revise the
RAMBAR attribute bits, including the write-protect and address space mask fields.
Remember that the SRAM cannot be accessed by the on-chip DMAs. The on-chip system
configuration allows concurrent core and DMA execution where the core can execute code
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SRAM Initialization
out of internal SRAM or cache during DMA access.
The ColdFire processor or an external emulator using the debug module can perform these
initialization functions.
4.5.1 SRAM Initialization Code
The code segment below initializes the SRAM. The code sets the base address of the SRAM
at 0x2000_0000 and then initializes the RAM to zeros.
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RAMBASE
RAMVALID
move.l
movec.l
EQU
0x20000000
EQU
0x00000035
#RAMBASE+RAMVALID,D0
D0, RAMBAR
;set this variable to 0x20000000
;load RAMBASE + valid bit into D0
;load RAMBAR and enable SRAM
The following loop initializes the entire SRAM to zero:
lea.l
move.l
RAMBASE,A0
#1024,D0
;load pointer to SRAM
;load loop counter into D0
(A0)+
#1,D0
SRAM_INIT_LOOP
;clear 4 bytes of SRAM
;decrement loop counter
;exit if done; else continue looping
SRAM_INIT_LOOP:
clr.l
subq.l
bne.b
The following function copies the number of bytesToMove from the source (*src) to the
processor’s local RAM at an offset relative to the SRAM base address defined by
destinationOffset. The bytesToMove must be a multiple of 16. For best performance, source
and destination SRAM addresses should be line-aligned (0-modulo-16).
; copyToCpuRam (*src, destinationOffset, bytesToMove)
RAMBASE
RAMFLAGS
lea.l
movem.l
;
;
;
;
;
;
;
;
stack
+0
+4
+8
+12
+16
+20
+24
EQU
EQU
0x20000000
0x00000035
-12(a7),a7
#0x1c,(a7)
;SRAM base address
;RAMBAR valid + mask bits
;allocate temporary space
;store D2/D3/D4 registers
arguments and locations
saved d2
saved d3
saved d4
returnPc
pointer to source operand
destinationOffset
bytesToMove
move.l
movec.l
RAMBASE+RAMFLAGS,a0
a0,rambar
;define RAMBAR contents
;load it
move.l
16(a7),a0
;load argument defining *src
lea.l
add.l
RAMBASE,a1
20(a7),a1
;memory pointer to RAM base
;include destinationOffset
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Power Management
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loop:
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move.l
asr.l
24(a7),d4
#4,d4
;load byte count
;divide by 16 to convert to loop count
.align
movem.l
movem.l
lea.l
lea.l
subq.l
bne.b
4
(a0),#0xf
#0xf,(a1)
16(a0),a0
16(a1),a1
#1,d4
loop
;force loop on 0-mod-4 address
;read 16 bytes from source
;store into RAM destination
;increment source pointer
;increment destination pointer
;decrement loop counter
;if done, then exit, else continue
movem.l
lea.l
rts
(a7),#0x1c
12(a7),a7
;restore d2/d3/d4 registers
;deallocate temporary space
4.6 Power Management
Because processor memory references may be simultaneously sent to an SRAM module
and cache, power can be minimized by configuring RAMBAR address space masks as
precisely as possible. For example, if an SRAM is mapped to the internal instruction bus
and contains instruction data, setting the ASn mask bits associated with operand references
can decrease power dissipation. Similarly, if the SRAM contains data, setting ASn bits
associated with instruction fetches minimizes power.
Table 4-2 shows typical RAMBAR configurations.
.
Table 4-2. Examples of Typical RAMBAR Settings
Data Contained in SRAM
RAMBAR[5–0]
Code only
0x2B
Data only
0x35
Both code and data
0x21
4.7 Cache Overview
This section describes the MCF5307 cache implementation, including organization,
configuration, and coherency. It describes cache operations and how the cache interacts
with other memory structures.
The MCF5307 processor contains a nonblocking, 8-Kbyte, 4-way set-associative, unified
(instruction and data) cache with a 16-byte line size. The cache improves system
performance by providing low-latency access to the instruction and data pipelines. This
decouples processor performance from system memory performance, increasing bus
availability for on-chip DMA or external devices. Figure 4-2 shows the organization and
integration of the data cache.
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Cache Organization
Cache
Control
External
Bus
Control
Control Logic
Control
Data Array
ColdFire
Processor
Core
Directory Array
Data
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System
Integration
Module
(SIM)
Address
Address/
Data
Data
Data Path
Address
Address Path
Figure 4-2. Unified Cache Organization
The cache supports operation of copyback, write-through, or cache-inhibited modes. The
cache lock feature can be used to guarantee deterministic response for critical code or data
areas.
A nonblocking cache services read hits or write hits from the processor while a fill (caused
by a cache allocation) is in progress. As Figure 4-2 shows, instruction and data accesses
use a single bus connected to the cache.
All addresses from the processor to the cache are physical addresses. A cache hit occurs
when an address matches a cache entry. For a read, the cache supplies data to the processor.
For a write, the processor updates the cache. If an access does not match a cache entry
(misses the cache) or if a write access must be written through to memory, the cache
performs a bus cycle on the internal bus and correspondingly on the external bus by way of
the system integration module (SIM).
The SRAM module does not implement bus snooping; cache coherency with other possible
bus masters must be maintained in software.
4.8 Cache Organization
A four-way set associative cache is organized as four ways (levels). There are 128 sets in
the 8-Kbyte cache with each line containing 16 bytes (4 longwords). Entire cache lines are
loaded from memory by burst-mode accesses that cache 4 longwords of data or
instructions. All 4 longwords must be loaded for the cache line to be valid.
Figure 4-3 shows cache organization as well as terminology used.
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Cache Organization
Way 0
Way 1
Way 2
Way 3
•
•
•
•
•
•
Line
•
•
•
•
•
•
Set 0
Set 1
Set 126
Set 127
Cache Line Format
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TAG
V
M
Longword 0
Longword 1
Longword 2
Longword 3
Where:
TAG—21-bit address tag
V—Valid bit for line
M—Modified bit for line
Figure 4-3. Cache Organization and Line Format
A set is a group of four lines (one from each level, or way), corresponding to the same index
into the cache array.
4.8.1 Cache Line States: Invalid, Valid-Unmodified, and
Valid-Modified
As shown in Table 4-3, a cache line can be invalid, valid-unmodified (often called
exclusive), or valid-modified.
Table 4-3. Valid and Modified Bit Settings
V
M
0
x
Invalid. Invalid lines are ignored during lookups.
Description
1
0
Valid, unmodified. Cache line has valid data that matches system memory.
1
1
Valid, modified. Cache line contains most recent data, data at system memory location is stale.
A valid line can be explicitly invalidated by executing a CPUSHL instruction.
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Cache Organization
4.8.2 The Cache at Start-Up
As Figure 4-4 (A) shows, after power-up, cache contents are undefined; V and M may be
set on some lines even though the cache may not contain the appropriate data for start up.
Because reset and power-up do not invalidate cache lines automatically, the cache should
be cleared explicitly by setting CACR[CINVA] before the cache is enabled (B).
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After the entire cache is flushed, cacheable entries are loaded first in way 0. If way 0 is
occupied, the cacheable entry is loaded into the same set in way 1, as shown in Figure 4-4
(D). This process is described in detail in Section 4.9, “Cache Operation.”
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Invalid (V = 0)
Valid, not modified (V = 1, M = 0)
Valid, modified (V = 1, M = 1)
A:Cache population at
start-up
B:Cache after invalidation, C:Cache after loads in
before it is enabled
Way 0
D:First load in Way 1
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
At reset, cache contents
are indeterminate; V and
M may be set. The cache
should be cleared
explicitly by setting
CACR[CINVA] before the
cache is enabled.
Setting CACR[CINVA]
invalidates the entire
cache.
Initial cacheable
accesses to memory-fill
positions in way 0.
A line is loaded in
way 1 only if that set is
full in way 0.
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Set 0
Set 127
Figure 4-4. Cache—A: at Reset, B: after Invalidation, C and D: Loading Pattern
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Cache Operation
4.9 Cache Operation
Figure 4-5 shows the general flow of a caching operation.
Address
31
11 10
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Tag Data/Tag Reference
4 3 0
Way 3
Way 2
Way 1
Way 0
Index
Set
Select
A[10:4]
Set 0
TAG
Set 1
•
•
•
•
•
•
Set 127
TAG
STATUS LW0 LW1 LW2 LW3
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
STATUS LW0 LW1 LW2 LW3
Address
A[31:11]
MUX
3
2
1
Comparator
0
Data or
Instruction
Line Select
Hit 3
Hit 2
Hit 1
Hit 0
Logical OR
Hit
Figure 4-5. Caching Operation
The following steps determine if a cache line is allocated for a given address:
1. The cache set index, A[10:4], selects one cache set.
2. A[31:11] and the cache set index are used as a tag reference or are used to update
the cache line tag field. Note that A[31:11] can specify 21 possible addresses that
can be mapped to one of the four ways.
3. The four tags from the selected cache set are compared with the tag reference. A
cache hit occurs if a tag matches the tag reference and the V bit is set, indicating that
the cache line contains valid data. If a cacheable write access hits in a valid cache
line, the write can occur to the cache line without having to load it from memory.
If the memory space is copyback, the updated cache line is marked modified
(M = 1), because the new data has made the data in memory out of date. If the
memory location is write-through, the write is passed on to system memory and the
M bit is never used. Note that the tag does not have TT or TM bits.
To allocate a cache entry, the cache set index selects one of the cache’s 128 sets. The cache
control logic looks for an invalid cache line to use for the new entry. If none is available,
the cache controller uses a pseudo-round-robin replacement algorithm to choose the line to
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be deallocated and replaced. First the cache controller looks for an invalid line, with way 0
the highest priority. If all lines have valid data, a 2-bit replacement counter is used to choose
the way. After a line is allocated, the pointer increments to point to the next way.
Cache lines from ways 0 and 1 can be protected from deallocation by enabling half-cache
locking. If CACR[HLCK] = 1, the replacement pointer is restricted to way 2 or 3.
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As part of deallocation, a valid, unmodified cache line is invalidated. It is consistent with
system memory, so memory does not need to be updated. To deallocate a modified cache
line, data is placed in a push buffer (for an external cache line push) before being
invalidated. After invalidation, the new entry can replace it. The old cache line may be
written after the new line is read.
When a cache line is selected to host a new cache entry, the following three things happen:
1. The new address tag bits A[31:11] are written to the tag.
2. The cache line is updated with the new memory data.
3. The cache line status changes to a valid state (V = 1).
Read cycles that miss in the cache allocate normally as previously described.
Write cycles that miss in the cache do not allocate on a cacheable write-through region, but
do allocate for addresses in a cacheable copyback region.
A copyback byte, word, longword, or line write miss causes the following:
1.
2.
3.
4.
The cache initiates a line fill or flush.
Space is allocated for a new line.
V and M are both set to indicate valid and modified.
Data is written in the allocated space. No write to memory occurs.
Note the following:
•
•
•
•
Read hits cannot change the status bits and no deallocation or replacement occurs;
the data or instructions are read from the cache.
If the cache hits on a write access, data is written to the appropriate portion of the
accessed cache line. Write hits in cacheable, write-through regions generate an
external write cycle and the cache line is marked valid, but is never marked modified.
Write hits in cacheable copyback regions do not perform an external write cycle; the
cache line is marked valid and modified (V = 1 and M = 1).
Misaligned accesses are broken into at least two cache accesses.
Validity is provided only on a line basis. Unless a whole line is loaded on a cache
miss, the cache controller does not validate data in the cache line.
Write accesses designated as cache-inhibited by the CACR or ACR bypass the cache and
perform a corresponding external write.
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Cache Operation
Normally, cache-inhibited reads bypass the cache and are performed on the external bus.
The exception to this normal operation occurs when all of the following conditions are true
during a cache-inhibited read:
•
•
•
The cache-inhibited fill buffer bit, CACR[DNFB], is set.
The access is an instruction read.
The access is normal (that is, transfer type (TT) equals 0).
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In this case, an entire line is fetched and stored in the fill buffer. It remains valid there, and
the cache can service additional read accesses from this buffer until either another fill or a
cache-invalidate-all operation occurs.
Valid cache entries that match during cache-inhibited address accesses are neither pushed
nor invalidated. Such a scenario suggests that the associated cache mode for this address
space was changed. To avoid this, it is generally recommended to use the CPUSHL
instruction to push or invalidate the cache entry or set CACR[CINVA] to invalidate the
cache before switching cache modes.
4.9.1 Caching Modes
For every memory reference generated by the processor or debug module, a set of effective
attributes is determined based on the address and the ACRs. Caching modes determine how
the cache handles an access. An access can be cacheable in either write-through or
copyback mode; it can be cache-inhibited in precise or imprecise modes. For normal
accesses, the ACRn[CM] bit corresponding to the address of the access specifies the
caching modes. If an address does not match an ACR, the default caching mode is defined
by CACR[DCM]. The specific algorithm is as follows:
if (address == ACR0-address including mask)
effective attributes = ACR0 attributes
else if (address == ACR1-address including mask)
effective attributes = ACR1 attributes
else effective attributes = CACR default attributes
Addresses matching an ACR can also be write-protected using ACR[W]. Addresses that do
not match either ACR can be write-protected using CACR[DW].
Reset disables the cache and clears all CACR bits. As shown in Figure 4-4, reset does not
automatically invalidate cache entries; they must be invalidated through software.
The ACRs allow the defaults selected in the CACR to be overridden. In addition, some
instructions (for example, CPUSHL) and processor core operations perform accesses that
have an implicit caching mode associated with them. The following sections discuss the
different caching accesses and their associated cache modes.
4.9.1.1 Cacheable Accesses
If ACRn[CM] or the default field of the CACR indicates write-through or copyback, the
access is cacheable. A read access to a write-through or copyback region is read from the
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cache if matching data is found. Otherwise, the data is read from memory and the cache is
updated. When a line is being read from memory for either a write-through or copyback
read miss, the longword within the line that contains the core-requested data is loaded first
and the requested data is given immediately to the processor, without waiting for the three
remaining longwords to reach the cache.
The following sections describe write-through and copyback modes in detail.
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4.9.1.2 Write-Through Mode
Write accesses to regions specified as write-through are always passed on to the external
bus, although the cycle can be buffered, depending on the state of CACR[ESB]. Writes in
write-through mode are handled with a no-write-allocate policy—that is, writes that miss
in the cache are written to the external bus but do not cause the corresponding line in
memory to be loaded into the cache. Write accesses that hit always write through to
memory and update matching cache lines. The cache supplies data to data-read accesses
that hit in the cache; read misses cause a new cache line to be loaded into the cache.
4.9.1.3 Copyback Mode
Copyback regions are typically used for local data structures or stacks to minimize external
bus use and reduce write-access latency. Write accesses to regions specified as copyback
that hit in the cache update the cache line and set the corresponding M bit without an
external bus access.
Be sure to flush the cache using the CPUSHL instruction before invalidating the cache in
copyback mode. Modified cache data is written to memory only if the line is replaced
because of a miss or a CPUSHL instruction pushes the line. If a byte, word, longword, or
line write access misses in the cache, the required cache line is read from memory, thereby
updating the cache. When a miss selects a modified cache line for replacement, the
modified cache data moves to the push buffer. The replacement line is read into the cache
and the push buffer contents are then written to memory.
4.9.2 Cache-Inhibited Accesses
Memory regions can be designated as cache-inhibited, which is useful for memory
containing targets such as I/O devices and shared data structures in multiprocessing
systems. It is also important to not cache the MCF5307 memory mapped registers. If the
corresponding ACRn[CM] or CACR[DCM] indicates cache-inhibited, precise or
imprecise, the access is cache-inhibited. The caching operation is identical for both
cache-inhibited modes, which differ only regarding recovery from an external bus error.
In determining whether a memory location is cacheable or cache-inhibited, the CPU checks
memory-control registers in the following order:
1. RAMBAR
2. ACR0
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Cache Operation
3. ACR1
4. If an access does not hit in the RAMBAR or the ACRs, the default is provided for
all accesses in CACR.
Cache-inhibited write accesses bypass the cache and a corresponding external write is
performed. Cache-inhibited reads bypass the cache and are performed on the external bus,
except when all of the following conditions are true:
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•
•
•
The cache-inhibited fill-buffer bit, CACR[DNFB], is set.
The access is an instruction read.
The access is normal (that is, TT = 0).
In this case, a fetched line is stored in the fill buffer and remains valid there; the cache can
service additional read accesses from this buffer until another fill occurs or a
cache-invalidate-all operation occurs.
If ACRn[CM] indicates cache-inhibited mode, precise or imprecise, the controller bypasses
the cache and performs an external transfer. If a line in the cache matches the address and
the mode is cache-inhibited, the cache does not automatically push the line if it is modified,
nor does it invalidate the line if it is valid. Before switching cache mode, execute a
CPUSHL instruction or set CACR[CINVA] to invalidate the entire cache.
If ACRn[CM] indicates precise mode, the sequence of read and write accesses to the region
is guaranteed to match the instruction sequence. In imprecise mode, the processor core
allows read accesses that hit in the cache to occur before completion of a pending write
from a previous instruction. Writes are not deferred past data-read accesses that miss the
cache (that is, that must be read from the bus).
Precise operation forces data-read accesses for an instruction to occur only once by
preventing the instruction from being interrupted after data is fetched. Otherwise, if the
processor is not in precise mode, an exception aborts the instruction and the data may be
accessed again when the instruction is restarted. These guarantees apply only when
ACRn[CM] indicates precise mode and aligned accesses.
CPU space-register accesses, such as MOVEC, are treated as cache-inhibited and precise.
4.9.3 Cache Protocol
The following sections describe the cache protocol for processor accesses and assumes that
the data is cacheable (that is, write-through or copyback).
4.9.3.1 Read Miss
A processor read that misses in the cache requests the cache controller to generate a bus
transaction. This bus transaction reads the needed line from memory and supplies the
required data to the processor core. The line is placed in the cache in the valid state.
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4.9.3.2 Write Miss
The cache controller handles processor writes that miss in the cache differently for
write-through and copyback regions. Write misses to copyback regions cause the cache line
to be read from system memory, as shown in Figure 4-6.
1. Writing character X to 0x0B generates a write miss. Data cannot be written to an invalid line.
Cache Line
0x0C 0x08
MCF5307
0x04
0x00
V=0
M=0
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X
2. The cache line (characters A–P) is updated from system memory, and line is marked valid.
0x0C 0x08 0x04 0x00
V=1
ABCD EFGH IJKL MNOP M = 0
System
Memory
3. After the cache line is filled, the write that initiated the write miss (the character X) completes to 0x0B.
MCF5307
0x0C 0x08 0x04 0x00
V=1
ABCD EXGH IJKL MNOP M = 1
Figure 4-6. Write-Miss in Copyback Mode
The new cache line is then updated with write data and the M bit is set for the line, leaving
it in modified state. Write misses to write-through regions write directly to memory without
loading the corresponding cache line into the cache.
4.9.3.3 Read Hit
On a read hit, the cache provides the data to the processor core and the cache line state
remains unchanged. If the cache mode changes for a specific region of address space, lines
in the cache corresponding to that region that contain modified data are not pushed out to
memory when a read hit occurs within that line. First execute a CPUSHL instruction or set
CACR[CINVA] before switching the cache mode.
4.9.3.4 Write Hit
The cache controller handles processor writes that hit in the cache differently for
write-through and copyback regions. For write hits to a write-through region, portions of
cache lines corresponding to the size of the access are updated with the data. The data is
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Cache Operation
also written to external memory. The cache line state is unchanged. For copyback accesses,
the cache controller updates the cache line and sets the M bit for the line. An external write
is not performed and the cache line state changes to (or remains in) the modified state.
4.9.4 Cache Coherency
The MCF5307 provides limited cache coherency support in multiple-master environments.
Both write-through and copyback memory update techniques are supported to maintain
coherency between the cache and memory.
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The cache does not support snooping (that is, cache coherency is not supported while
external or DMA masters are using the bus). Therefore, on-chip DMAs of the MCF5307
cannot access local memory and do not maintain coherency with the unified cache.
4.9.5 Memory Accesses for Cache Maintenance
The cache controller performs all maintenance activities that supply data from the cache to
the core, including requests to the SIM for reading new cache lines and writing modified
lines to memory. The following sections describe memory accesses resulting from cache
fill and push operations. Chapter 18, “Bus Operation,” describes required bus cycles in
detail.
4.9.5.1 Cache Filling
When a new cache line is required, a line read is requested from the SIM, which generates
a burst-read transfer by indicating a line access with the size signals, SIZ[1:0].
The responding device supplies 4 consecutive longwords of data. Burst operations can be
inhibited or enabled through the burst read/write enable bits (BSTR/BSTW) in the
chip-select control registers (CSCR0–CSCR7).
SIM line accesses implicitly request burst-mode operations from memory. For more
information regarding external bus burst-mode accesses, see Chapter 18, “Bus Operation.”
The first cycle of a cache-line read loads the longword entry corresponding to the requested
address. Subsequent transfers load the remaining longword entries.
A burst operation is aborted by an a write-protection fault, which is the only possible access
error. Exception processing proceeds immediately. Because the write cycle can be
decoupled from the processor’s issuing of the operation, error signaling appears to be
decoupled from the instruction that generated the write. Accordingly, the PC in the
exception stack frame represents the program location when the access error was signaled.
See Section 2.8.2, “Processor Exceptions.”
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4.9.5.2 Cache Pushes
Cache pushes occur for line replacement and as required for the execution of the CPUSHL
instruction. To reduce the requested data’s latency in the new line, the modified line being
replaced is temporarily placed in the push buffer while the new line is fetched from
memory. After the bus transfer for the new line completes, the modified cache line is written
back to memory and the push buffer is invalidated.
4.9.5.2.1 Push and Store Buffers
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The 16-byte push buffer reduces latency for requested new data on a cache miss by holding
a displaced modified cache line while the new data is read from memory.
If a cache miss displaces a modified line, a miss read reference is immediately generated.
While waiting for the response, the current contents of the cache location load into the push
buffer. When the burst-read bus transaction completes, the cache controller can generate the
appropriate line-write bus transaction to write the push buffer contents into memory.
In imprecise mode, the FIFO store buffer can defer pending writes to maximize
performance. The store buffer can support as many as four entries (16 bytes maximum) for
this purpose.
Data writes destined for the store buffer cannot stall the core. The store buffer effectively
provides a measure of decoupling between the pipeline’s ability to generate writes (one per
cycle maximum) and the external bus’s ability to retire those writes. In imprecise mode,
writes stall only if the store buffer is full and a write operation is on the internal bus. The
internal write cycle is held, stalling the data execution pipeline.
If the store buffer is not used (that is, store buffer disabled or cache-inhibited precise mode),
external bus cycles are generated directly for each pipeline write operation. The instruction
is held in the pipeline until external bus transfer termination is received. Therefore, each
write is stalled for 5 cycles, making the minimum write time equal to 6 cycles when the
store buffer is not used. See Section 2.1.2.2, “Operand Execution Pipeline (OEP).”
The store buffer enable bit, CACR[ESB], controls the enabling of the store buffer. This bit
can be set and cleared by the MOVEC instruction. ESB is zero at reset and all writes are
performed in order (precise mode). ACRn[CM] or CACR[DCM] generates the mode used
when ESB is set. Cacheable write-through and cache-inhibited imprecise modes use the
store buffer.
The store buffer can queue data as much as 4 bytes wide per entry. Each entry matches the
corresponding bus cycle it generates; therefore, a misaligned longword write to a
write-through region creates two entries if the address is to an odd-word boundary. It
creates three entries if it is to an odd-byte boundary—one per bus cycle.
4.9.5.2.2 Push and Store Buffer Bus Operation
As soon as the push or store buffer has valid data, the internal bus controller uses the next
available external bus cycle to generate the appropriate write cycles. In the event that
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Cache Operation
another cache fill is required (for example, cache miss to process) during the continued
instruction execution by the processor pipeline, the pipeline stalls until the push and store
buffers are empty, then generate the required external bus transaction.
Supervisor instructions, the NOP instruction, and exception processing synchronize the
processor core and guarantee the push and store buffers are empty before proceeding. Note
that the NOP instruction should be used only to synchronize the pipeline. The preferred
no-operation function is the TPF instruction.
4.9.6 Cache Locking
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Ways 0 and 1 of the cache can be locked by setting CACR[HLCK]. If the cache is locked,
cache lines in ways 0 and 1 are not subject to being deallocated by normal cache operations.
As Figure 4-7 (B and C) shows, the algorithm for updating the cache and for identifying
cache lines to be deallocated is otherwise unchanged. If ways 2 and 3 are entirely invalid,
cacheable accesses are first allocated in way 2. Way 3 is not used until the location in way 2
is occupied.
Ways 0 and 1 are still updated on write hits (D in Figure 4-7) and may be pushed or cleared
only explicitly by using specific cache push/invalidate instructions. However, new cache
lines cannot be allocated in ways 0 and 1.
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Invalid (V = 0)
Valid, not modified (V = 1, M = 0)
Valid, modified (V = 1, M = 1)
A:Ways 0 and 1 are filled.
Ways 2 and 3 are
invalid.
B:CACR[DHLCK] is set,
locking ways 0 and 1.
C:When a set in Way 2 is
D:Write hits to ways 0
occupied, the set in way 3 and 1 update cache
is used for a cacheable
lines.
access.
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
After CACR[HLCK] is
set, subsequent cache
accesses go to ways 2
and 3.
While the cache is
locked and after a
position in ways is full,
the set in Way 3 is
updated.
While the cache is
locked, ways 0 and 1 can
be updated by write hits.
In this example, memory
is configured as
copyback, so updated
cache lines are marked
modified.
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Set 0
Set 127
After reset, the cache is
invalidated, ways 0 and 1
are then written with data
that should not be
deallocated.
Figure 4-7. Cache Locking
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Cache Registers
4.10 Cache Registers
This section describes the MCF5307 implementation of the Version 3 cache registers.
4.10.1 Cache Control Register (CACR)
The CACR in Figure 4-8 contains bits for configuring the cache. It can be written by the
MOVEC register instruction and can be read or written from the debug facility. A hardware
reset clears CACR, which disables the cache; however, reset does not affect the tags, state
information, or data in the cache.
31
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Field EC
30
29
28
27
—
ESB
DPI
HLCK
26
25
—
Reset
24
23
20
CINVA
19
18
17
16
—
0000_0000_0000_0000
R/W
Write (R/W by debug module)
15
Field
14
13
12
11
—
10
9
DNFB
Reset
8
DCM
7
0
—
DW
—
0000_0000_0000_0000
R/W
Write (R/W by debug module)
Rc
0x002
Figure 4-8. Cache Control Register (CACR)
Table 4-4 describes CACR fields.
Table 4-4. CACR Field Descriptions
Bits
Name
31
EC
Description
Enable cache.
0 Cache disabled. The cache is not operational, but data and tags are preserved.
1 Cache enabled.
30
—
Reserved, should be cleared.
29
ESB
Enable store buffer.
0 Writes to write-through or noncachable in imprecise mode bypass the store buffer and
generate bus cycles directly. Section 4.9.5.2.1, “Push and Store Buffers,” describes the
performance penalty for this.
1 The four-entry FIFO store buffer is enabled; when imprecise mode is used, this buffer defers
pending writes to write-through or cache-inhibited regions to maximize performance.
Cache-inhibited, precise-mode accesses always bypass the store buffer.
28
DPI
Disable CPUSHL invalidation.
0 Normal operation. A CPUSHL instruction causes the selected line to be pushed if modified and
then invalidated.
1 No clear operation. A CPUSHL instruction causes the selected line to be pushed if modified,
then left valid.
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Table 4-4. CACR Field Descriptions (Continued)
Bits
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27
Name
Description
HLCK
Half-cache lock mode
0 Normal operation. The cache allocates the lowest invalid way. If all ways are valid, the cache
allocates the way pointed at by the counter and then increments this counter modulo-4.
1 Half-cache operation. The cache allocates to the lower invalid way of levels 2 and 3; if both are
valid, the cache allocates to way 2 if the high-order bit of the round-robin counter is zero;
otherwise, it allocates way 3 and increments the round-robin counter modulo-2. This locks the
content of ways 0 and 1. Ways 0 and 1 are still updated on write hits and may be pushed or
cleared by specific cache push/invalidate instructions.
This implementation allows maximum use of available cache memory and provides the flexibility
of setting HLCK before, during, or after allocations occur.
26–25 —
Reserved, should be cleared.
24
Cache invalidate all. Writing a 1 to this bit initiates entire cache invalidation. Once invalidation is
complete, this bit automatically returns to 0; it is not necessary to clear it explicitly. Note the
caches are not cleared on power-up or normal reset, as shown in Figure 4-4.
0 No invalidation is performed.
1 Initiate invalidation of the entire cache. The cache controller sequentially clears V and M bits in
all sets. Subsequent accesses stall until the invalidation is finished, at which point, this bit is
automatically cleared. In copyback mode, the cache should be flushed using a CPUSHL
instruction before setting this bit.
CINVA
23–11
—
Reserved, should be cleared.
10
DNFB
Default noncacheable fill buffer. Determines if the fill buffer can store noncacheable accesses
0 Fill buffer not used to store noncacheable instruction accesses (16 or 32 bits).
1 Fill buffer used to store noncacheable accesses. The fill buffer is used only for normal (TT = 0)
instruction reads of a noncacheable region. Instructions are loaded into the fill buffer by a burst
access (same as a line fill). They stay in the buffer until they are displaced, so subsequent
accesses may not appear on the external bus.
Note that this feature can cause a coherency problem for self-modifying code. If DNFB = 1 and a
cache-inhibited access uses the fill buffer, instructions remain valid in the fill buffer until a
cache-invalidate-all instruction, another cache-inhibited burst, or a miss that initiates a fill. A write
to the line in the fill buffer goes to the external bus without updating or invalidating the buffer.
Subsequent reads of that written data are serviced by the fill buffer and receive stale information.
9–8
DCM
Default cache mode. Selects the default cache mode and access precision as follows:
00 Cacheable, write-through
01 Cacheable, copy-back
10 Cache-inhibited, precise exception model
11 Cache-inhibited, imprecise exception model. Precise and imprecise modes are described in
Section 4.9.2, “Cache-Inhibited Accesses.”
7–6
—
Reserved, should be cleared.
5
DW
Default write protect. Use of this bit is described in Section 4.9.1, “Caching Modes.”
0 Read and write accesses permitted
1 Write accesses not permitted
4–0
—
Reserved, should be cleared.
4.10.2 Access Control Registers (ACR0–ACR1)
The ACRs, Figure 4-9, assign control attributes, such as cache mode and write protection,
to specified memory regions. Registers are accessed with the MOVEC instruction with the
Rc encodings in Figure 4-9.
For overlapping regions, ACR0 takes priority. Data transfers to and from these registers are
longword transfers. Bits 12–7, 4, 3, 1, and 0 are always read as zeros.
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Cache Registers
NOTE:
The SIM MBAR region should be mapped as cache-inhibited
through an ACR.
31
Field
24 23
Address Base
Reset
16 15 14 13 12
Address Mask
Uninitialized
R/W
S
7
6
—
0
5
CM
4
3
—
2
1
W
0
—
Uninitialized
Write (R/W by debug module)
Rc
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E
ACR0: 0x004; ACR1: 0x005
Figure 4-9. Access Control Register Format (ACRn)
Table 4-5 describes ACRn fields.
I
Table 4-5. ACRn Field Descriptions
Bits
Name
Description
31–24
Address
base
Address base. Compared with address bits A[31:24]. Eligible addresses that match are
assigned the access control attributes of this register.
23–16
Address
mask
Address mask. Setting a mask bit causes the corresponding address base bit to be ignored.
The low-order mask bits can be set to define contiguous regions larger than 16 Mbytes. The
mask can define multiple noncontiguous regions of memory.
15
E
Enable. Enables or disables the other ACRn bits.
0 Access control attributes disabled
1 Access control attributes enabled
14–13
S
Supervisor mode. Specifies whether only user or supervisor accesses are allowed in this
address range or if the type of access is a don’t care.
00 Match addresses only in user mode
01 Match addresses only in supervisor mode
1x Execute cache matching on all accesses
12–7
—
Reserved; should be cleared.
6–5
CM
Cache mode. Selects the cache mode and access precision. Precise and imprecise modes are
described in Section 4.9.2, “Cache-Inhibited Accesses.”
00 Cacheable, write-through
01 Cacheable, copyback
10 Cache-inhibited, precise
11 Cache-inhibited, imprecise
4–3
—
Reserved, should be cleared.
2
W
Write protect. Selects the write privilege of the memory region.
0 Read and write accesses permitted
1 Write accesses not permitted
1–0
—
Reserved, should be cleared.
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Cache Management
4.11 Cache Management
The cache can be enabled and configured by using a MOVEC instruction to access CACR.
A hardware reset clears CACR, disabling the cache and removing all configuration
information; however, reset does not affect the tags, state information, and data in the cache.
Set CACR[CINVA] to invalidate the cache before enabling it.
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The privileged CPUSHL instruction supports cache management by selectively pushing
and invalidating cache lines. The address register used with CPUSHL directly addresses the
cache’s directory array. The CPUSHL instruction flushes a cache line.
The value of CACR[DPI] determines whether CPUSHL invalidates a cache line after it is
pushed. To push the entire cache, implement a software loop to index through all sets and
through each of the four lines within each set (a total of 512 lines). The state of CACR[EC]
does not affect the operation of CPUSHL or CACR[CINVA]. Disabling the cache by setting
CACR[EC] makes the cache nonoperational without affecting tags, state information, or
contents.
The contents of An used with CPUSHL specify cache row and line indexes. This differs
from the MC68040 where a physical address is specified. Figure 4-10 shows the An format.
31
11
10
0
4
Set Index
3
0
Line Index
Figure 4-10. An Format
The following code example flushes the entire cache:
_cache_disable:
nop
move.w
jsr
clr.l
movec
movec
move.l
movec
rts
#0x2700,SR
_cache_flush
d0
d0,ACR0
d0,ACR1
#0x01000000,d0
d0,CACR
;mask off IRQs
;flush the cache completely
;ACR0 off
;ACR1 off
;Invalidate and disable cache
_cache_flush:
nop
moveq.l
moveq.l
move.l
#0,d0
#0,d1
d0,a0
;synchronize—flush store buffer
;initialize way counter
;initialize set counter
;initialize cpushl pointer
setloop:
cpushl
add.l
addq.l
cmpi.l
bne
bc,(a0)
#0x0010,a0
#1,d1
#128,d1
setloop
;push cache line a0
;increment set index by 1
;increment set counter
;are sets for this way done?
#0,d1
#1,d0
;set counter to zero again
;increment to next way
moveq.l
addq.l
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Cache Operation Summary
move.l
cmpi.l
bne
rts
d0,a0
#4,d0
setloop
;set = 0, way = d0
;flushed all the ways?
The following CACR loads assume the default cache mode is copyback.
CacheLoadAndLock:
move.l
movec
#0xA1000100,d0; enable and invalidate cache ...
d0,cacr ; ... in the CACR
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The following code preloads half of the cache (4 Kbytes). It assumes a contiguous block of
data is to be mapped into the cache, starting at a 0-modulo-4K address.
move.l
lea
CacheLoop:
tst.b
lea
subq.l
bne.b
#256,d0
data_,a0
;256 16-byte lines in 4K space
; load pointer defining data area
(a0)
16(a0),a0
#1,d0
CacheLoop
;touch location + load into data cache
;increment address to next line
;decrement loop counter
;if done, then exit, else continue
; A 4K region has been loaded into levels 0 and 1 of the 8K cache. lock it!
move.l
movec
rts
#0xA8000100,d0
d0,cacr
align
16
;set the cache lock bit ...
; ... in the CACR
4.12 Cache Operation Summary
This section gives operational details for the cache and presents cache-line state diagrams.
4.12.1 Cache State Transitions
Using the V and M bits, the cache supports a line-based protocol allowing individual cache
lines to be invalid, valid, or modified. To maintain memory coherency, the cache supports
both write-through and copyback modes, specified by the corresponding ACR[CM], or
CACR[DCM] if no ACR matches.
Read or write misses to copyback regions cause the cache controller to read a cache line
from memory into the cache. If available, tag and data from memory update an invalid line
in the selected set. The line state then changes from invalid to valid by setting the V bit. If
all lines in the row are already valid or modified, the pseudo-round-robin replacement
algorithm selects one of the four lines and replaces the tag and data. Before replacement,
modified lines are temporarily buffered and later copied back to memory after the new line
has been read from memory.
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Cache Operation Summary
Figure 4-11 shows the three possible cache line states and possible processor-initiated
transitions for memory configured as copyback. Transitions are labeled with a capital letter
indicating the previous state and a number indicating the specific case listed in Table 4-11.
CI5—CINVA
CI6—CPUSHL & DPI
CI7—CPUSHL & DPI
CV1—CPU read miss
CV2—CPU read hit
CV7—CPUSHL & DPI
CI1—CPU read miss
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Invalid
V=0
Valid
V=1
M=0
CV5—CINVA
CV6—CPUSHL & DPI
CI3—CPU
write miss
CD1—CPU
read miss
CD7—CPUSHL
& DPI
CD5—CINVA
CV3—CPU write miss
CD6—CPUSHL & DPI
CV4—CPU write hit
Modified
V=1
M=1
CD2—CPU read hit
CD3—CPU write miss
CD4—CPU write hit
Figure 4-11. Cache Line State Diagram—Copyback Mode
Figure 4-12 shows the two possible states for a cache line in write-through mode.
WV1—CPU read miss
WV2—CPU read hit
WV3—CPU write miss
WV4—CPU write hit
WV7—CPUSHL & DPI
WI3—CPU write miss
WI5—CINVA
WI6—CPUSHL & DPI
WI7—CPUSHL & DPI
WI1—CPU read miss
Invalid
V=0
Valid
V=1
WV5—CINVA
WV6—CPUSHL & DPI
Figure 4-12. Cache Line State Diagram—Write-Through Mode
Table 4-6 describes cache line transitions and the accesses that cause them.
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Cache Operation Summary
Table 4-6. Cache Line State Transitions
Current State
Access
Invalid (V = 0)
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Valid (V = 1, M = 0)
Modified (V = 1, M = 1)
Read
miss
(C,W)I1 Read line from
memory and update
cache;
supply data to
processor;
go to valid state.
(C,W)V1 Read new line from
memory and update
cache;
supply data to processor;
stay in valid state.
CD1 Push modified line to
buffer;
read new line from memory
and update cache;
supply data to processor;
write push buffer contents
to memory;
go to valid state.
Read hit
(C,W)I2 Not possible.
(C,W)V2 Supply data to processor;
stay in valid state.
CD2 Supply data to processor;
stay in modified state.
Write
miss
(copyback)
CI3
Read line from
memory and update
cache;
write data to cache;
go to modified state.
CV3
Read new line from
memory and update
cache;
write data to cache;
go to modified state.
CD3 Push modified line to
buffer;
read new line from memory
and update cache;
write push buffer contents
to memory;
stay in modified state.
Write
miss
(writethrough)
WI3
Write data to
memory;
stay in invalid state.
WV3
Write data to memory;
stay in valid state.
WD3 Write data to memory;
stay in modified state.
Cache mode changed for
the region corresponding to
this line. To avoid this state,
execute a CPUSHL
instruction or set
CACR[CINVA] before
switching modes.
Write hit
(copyback)
CI4
Not possible.
CV4
Write data to cache;
go to modified state.
CD4 Write data to cache;
stay in modified state.
Write hit
(writethrough)
WI4
Not possible.
WV4
Write data to memory and
to cache;
stay in valid state.
WD4 Write data to memory and
to cache;
go to valid state.
Cache mode changed for
the region corresponding to
this line. To avoid this state,
execute a CPUSHL
instruction or set
CACR[CINVA] before
switching modes.
Cache
(C,W)I5 No action;
invalidate
stay in invalid state.
(C,W)V5 No action;
go to invalid state.
CD5 No action (modified data
lost);
go to invalid state.
Cache
push
(C,W)V6 No action;
go to invalid state.
CD6 Push modified line to
memory;
go to invalid state.
(C,W)V7 No action;
stay in valid state.
CD7 Push modified line to
memory;
go to valid state.
(C,W)I6 No action;
(C,W)I7 stay in invalid state.
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Cache Operation Summary
The following tables present the same information as Table 4-6, organized by the current
state of the cache line. In Table 4-7 the current state is invalid.
Table 4-7. Cache Line State Transitions (Current State Invalid)
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Access
Response
Read miss
(C,W)I1 Read line from memory and update cache;
supply data to processor;
go to valid state.
Read hit
(C,W)I2 Not possible
Write miss (copyback)
CI3
Read line from memory and update cache;
write data to cache;
go to modified state.
Write miss (write-through)
WI3
Write data to memory;
stay in invalid state.
Write hit (copyback)
CI4
Not possible
Write hit (write-through)
WI4
Not possible
Cache invalidate
(C,W)I5 No action;
stay in invalid state.
Cache push
(C,W)I6 No action;
stay in invalid state.
Cache push
(C,W)I7 No action;
stay in invalid state.
In Table 4-8 the current state is valid.
Table 4-8. Cache Line State Transitions (Current State Valid)
Access
4-28
Response
Read miss
(C,W)V1 Read new line from memory and update cache;
supply data to processor; stay in valid state.
Read hit
(C,W)V2 Supply data to processor;
stay in valid state.
Write miss (copyback)
CV3
Read new line from memory and update cache;
write data to cache;
go to modified state.
Write miss (write-through)
WV3
Write data to memory;
stay in valid state.
Write hit (copyback)
CV4
Write data to cache;
go to modified state.
Write hit (write-through)
WV4
Write data to memory and to cache;
stay in valid state.
Cache invalidate
(C,W)V5 No action;
go to invalid state.
Cache push
(C,W)V6 No action;
go to invalid state.
Cache push
(C,W)V7 No action;
stay in valid state.
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Cache Initialization Code
In the current state is modified.
Table 4-9. Cache Line State Transitions (Current State Modified)
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Access
Response
Read miss
CD1 Push modified line to buffer;
read new line from memory and update cache;
supply data to processor;
write push buffer contents to memory;
go to valid state.
Read hit
CD2 Supply data to processor;
stay in modified state.
Write miss
(copyback)
CD3 Push modified line to buffer;
read new line from memory and update cache;
write push buffer contents to memory;
stay in modified state.
Write miss
(write-through)
WD3 Write data to memory;
stay in modified state.
Cache mode changed for the region corresponding to this line. To avoid this state,
execute a CPUSHL instruction or set CACR[CINVA] before switching modes.
Write hit
(copyback)
CD4 Write data to cache;
stay in modified state.
Write hit
(write-through)
WD4 Write data to memory and to cache;
go to valid state.
Cache mode changed for the region corresponding to this line. To avoid this state,
execute a CPUSHL instruction or set CACR[CINVA] before switching modes.
Cache invalidate
CD5 No action (modified data lost);
go to invalid state.
Cache push
CD6 Push modified line to memory;
go to invalid state.
Cache push
CD7 Push modified line to memory;
go to valid state.
4.13 Cache Initialization Code
The following example sets up the cache for FLASH or ROM space only.
move.l#0x81000300,D0 //enable cache, invalidate it,
//default mode is cache-inhibited imprecise
movecD0, CACR
move.l #0xFF00C000,D0//cache FLASH space, enable,
//ignore FC2, cacheable, writethrough
movecD0,ACR0
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Cache Initialization Code
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Chapter 5
Debug Support
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This chapter describes the Revision B enhanced hardware debug support in the MC5307.
This revision of the ColdFire debug architecture encompasses the earlier revision.
5.1 Overview
The debug module is shown in Figure 5-1.
High-speed
local bus
ColdFire CPU Core
Debug Module
Control
BKPT
Trace Port
PST[3:0], DDATA[3:0]
PSTCLK
Communication Port
DSCLK, DSI, DSO
Figure 5-1. Processor/Debug Module Interface
Debug support is divided into three areas:
•
•
•
Real-time trace support—The ability to determine the dynamic execution path
through an application is fundamental for debugging. The ColdFire solution
implements an 8-bit parallel output bus that reports processor execution status and
data to an external emulator system. See Section 5.3, “Real-Time Trace Support.”
Background debug mode (BDM)—Provides low-level debugging in the ColdFire
processor complex. In BDM, the processor complex is halted and a variety of
commands can be sent to the processor to access memory and registers. The external
emulator uses a three-pin, serial, full-duplex channel. See Section 5.5, “Background
Debug Mode (BDM),” and Section 5.4, “Programming Model.”
Real-time debug support—BDM requires the processor to be halted, which many
real-time embedded applications cannot do. Debug interrupts let real-time systems
execute a unique service routine that can quickly save the contents of key registers
and variables and return the system to normal operation. The emulator can access
saved data because the hardware supports concurrent operation of the processor and
BDM-initiated commands. See Section 5.6, “Real-Time Debug Support.”
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Signal Description
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The Version 2 ColdFire core implemented the original debug architecture, now called
Revision A. Based on feedback from customers and third-party developers, enhancements
have been added to succeeding generations of ColdFire cores. The Version 3 core
implements Revision B of the debug architecture, providing more flexibility for configuring
the hardware breakpoint trigger registers and removing the restrictions involving
concurrent BDM processing while hardware breakpoint registers are active.
5.2 Signal Description
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Table 5-1 describes debug module signals. All ColdFire debug signals are unidirectional
and related to a rising edge of the processor core’s clock signal. The standard 26-pin debug
connector is shown in Section 5.7, “Motorola-Recommended BDM Pinout.”
Table 5-1. Debug Module Signals
Signal
Description
Development Serial
Clock (DSCLK)
Internally synchronized input. (The logic level on DSCLK is validated if it has the same value on
two consecutive rising CLKIN edges.) Clocks the serial communication port to the debug
module. Maximum frequency is 1/5 the processor CLK speed. At the synchronized rising edge
of DSCLK, the data input on DSI is sampled and DSO changes state.
Development Serial
Input (DSI)
Internally synchronized input that provides data input for the serial communication port to the
debug module.
Development Serial
Output (DSO)
Provides serial output communication for debug module responses. DSO is registered
internally.
Breakpoint (BKPT)
Input used to request a manual breakpoint. Assertion of BKPT puts the processor into a halted
state after the current instruction completes. Halt status is reflected on processor status/debug
data signals (PST[3:0]) as the value 0xF. If CSR[BKD] is set (disabling normal BKPT
functionality), asserting BKPT generates a debug interrupt exception in the processor.
Processor Status
Clock (PSTCLK)
Delayed version of the processor clock. Its rising edge appears in the center of valid PST and
DDATA output. See Figure 5-2. PSTCLK indicates when the development system should
sample PST and DDATA values.
If real-time trace is not used, setting CSR[PCD] keeps PSTCLK, PST and DDATA outputs from
toggling without disabling triggers. Non-quiescent operation can be reenabled by clearing
CSR[PCD], although the emulator must resynchronize with the PST and DDATA outputs.
PSTCLK starts clocking only when the first non-zero PST value (0xC, 0xD, or 0xF) occurs
during system reset exception processing. Table 5-2 describes PST values. Chapter 7,
“Phase-Locked Loop (PLL),” describes PSTCLK generation.
Debug Data
(DDATA[3:0])
These output signals display the hardware register breakpoint status as a default, or optionally,
captured address and operand values. The capturing of data values is controlled by the setting
of the CSR. Additionally, execution of the WDDATA instruction by the processor captures
operands which are displayed on DDATA. These signals are updated each processor cycle.
Processor Status
(PST[3:0])
These output signals report the processor status. Table 5-2 shows the encoding of these
signals. These outputs indicate the current status of the processor pipeline and, as a result, are
not related to the current bus transfer. The PST value is updated each processor cycle.
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Real-Time Trace Support
Figure 5-2 shows PSTCLK timing with respect to PST and DDATA.
PSTCLK
PST or DDATA
Figure 5-2. PSTCLK Timing
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5.3 Real-Time Trace Support
Real-time trace, which defines the dynamic execution path, is a fundamental debug
function. The ColdFire solution is to include a parallel output port providing encoded
processor status and data to an external development system. This port is partitioned into
two 4-bit nibbles: one nibble allows the processor to transmit processor status, (PST), and
the other allows operand data to be displayed (debug data, DDATA). The processor status
may not be related to the current bus transfer.
External development systems can use PST outputs with an external image of the program
to completely track the dynamic execution path. This tracking is complicated by any
change in flow, especially when branch target address calculation is based on the contents
of a program-visible register (variant addressing). DDATA outputs can be configured to
display the target address of such instructions in sequential nibble increments across
multiple processor clock cycles, as described in Section 5.3.1, “Begin Execution of Taken
Branch (PST = 0x5).” Two 32-bit storage elements form a FIFO buffer connecting the
processor’s high-speed local bus to the external development system through PST[3:0] and
DDATA[3:0]. The buffer captures branch target addresses and certain data values for
eventual display on the DDATA port, one nibble at a time starting with the lsb.
Execution speed is affected only when both storage elements contain valid data to be
dumped to the DDATA port. The core stalls until one FIFO entry is available.
Table 5-2 shows the encoding of these signals.
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Table 5-2. Processor Status Encoding
PST[3:0]
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Definition
Hex
Binary
0x0
0000
Continue execution. Many instructions execute in one processor cycle. If an instruction requires more
clock cycles, subsequent clock cycles are indicated by driving PST outputs with this encoding.
0x1
0001
Begin execution of one instruction. For most instructions, this encoding signals the first clock cycle of
an instruction’s execution. Certain change-of-flow opcodes, plus the PULSE and WDDATA instructions,
generate different encodings.
0x2
0010
Reserved
0x3
0011
Entry into user-mode. Signaled after execution of the instruction that caused the ColdFire processor to
enter user mode.
0x4
0100
Begin execution of PULSE and WDDATA instructions. PULSE defines logic analyzer triggers for debug
and/or performance analysis. WDDATA lets the core write any operand (byte, word, or longword)
directly to the DDATA port, independent of debug module configuration. When WDDATA is executed, a
value of 0x4 is signaled on the PST port, followed by the appropriate marker, and then the data transfer
on the DDATA port. Transfer length depends on the WDDATA operand size.
0x5
0101
Begin execution of taken branch. For some opcodes, a branch target address may be displayed on
DDATA depending on the CSR settings. CSR also controls the number of address bytes displayed,
indicated by the PST marker value preceding the DDATA nibble that begins the data output. See
Section 5.3.1, “Begin Execution of Taken Branch (PST = 0x5).”
0x6
0110
Reserved
0x7
0111
Begin execution of return from exception (RTE) instruction.
0x8–
0xB
1000–
1011
Indicates the number of bytes to be displayed on the DDATA port on subsequent clock cycles. The
value is driven onto the PST port one clock PSTCLK cycle before the data is displayed on DDATA.
0x8 Begin 1-byte transfer on DDATA.
0x9 Begin 2-byte transfer on DDATA.
0xA Begin 3-byte transfer on DDATA.
0xB Begin 4-byte transfer on DDATA.
0xC
1100
Exception processing. Exceptions that enter emulation mode (debug interrupt or optionally trace)
generate a different encoding, as described below. Because the 0xC encoding defines a multiple-cycle
mode, PST outputs are driven with 0xC until exception processing completes.
0xD
1101
Entry into emulator mode. Displayed during emulation mode (debug interrupt or optionally trace).
Because this encoding defines a multiple-cycle mode, PSToutputs are driven with 0xD until exception
processing completes.
0xE
1110
Processor is stopped. Appears in multiple-cycle format when the MCF5307 executes a STOP
instruction. The ColdFire processor remains stopped until an interrupt occurs, thus PST outputs
display 0xE until the stopped mode is exited.
0xF
1111
Processor is halted. Because this encoding defines a multiple-cycle mode, the PST outputs display
0xF until the processor is restarted or reset. (see Section 5.5.1, “CPU Halt”)
5.3.1 Begin Execution of Taken Branch (PST = 0x5)
PST is 0x5 when a taken branch is executed. For some opcodes, a branch target address may
be displayed on DDATA depending on the CSR settings. CSR also controls the number of
address bytes displayed, which is indicated by the PST marker value immediately
preceding the DDATA nibble that begins the data output.
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Programming Model
Bytes are displayed in least-to-most-significant order. The processor captures only those
target addresses associated with taken branches which use a variant addressing mode, that
is, RTE and RTS instructions, JMP and JSR instructions using address register indirect or
indexed addressing modes, and all exception vectors.
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The simplest example of a branch instruction using a variant address is the compiled code
for a C language case statement. Typically, the evaluation of this statement uses the variable
of an expression as an index into a table of offsets, where each offset points to a unique case
within the structure. For such change-of-flow operations, the MCF5307 uses the debug pins
to output the following sequence of information on successive processor clock cycles:
1. Use PST (0x5) to identify that a taken branch was executed.
2. Using the PST pins, optionally signal the target address to be displayed sequentially
on the DDATA pins. Encodings 0x9–0xB identify the number of bytes displayed.
3. The new target address is optionally available on subsequent cycles using the
DDATA port. The number of bytes of the target address displayed on this port is
configurable (2, 3, or 4 bytes).
Another example of a variant branch instruction would be a JMP (A0) instruction.
Figure 5-3 shows when the PST and DDATA outputs that indicate when a JMP (A0)
executed, assuming the CSR was programmed to display the lower 2 bytes of an address.
PSTCLK
PST
0x5
0x9
DDATA
0x0
0x0
A[3:0]
A[7:4]
A[11:8]
A[15:12]
Figure 5-3. Example JMP Instruction Output on PST/DDATA
PST is driven with a 0x5 in the first cycle and 0x9 in the second. The 0x5 indicates a taken
branch and the marker value 0x9 indicates a 2-byte address. Thus, the 4 subsequent DDATA
nibbles display the lower 2 bytes of address register A0 in least-to-most-significant nibble
order. The PST output after the JMP instruction completes depends on the target
instruction. The PST can continue with the next instruction before the address has
completely displayed on DDATA because of the DDATA FIFO. If the FIFO is full and the
next instruction has captured values to display on DDATA, the pipeline stalls (PST = 0x0)
until space is available in the FIFO.
5.4 Programming Model
In addition to the existing BDM commands that provide access to the processor’s registers
and the memory subsystem, the debug module contains nine registers to support the
required functionality. These registers are also accessible from the processor’s supervisor
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programming model by executing the WDEBUG instruction. Thus, the breakpoint
hardware in the debug module can be accessed by the external development system using
the debug serial interface or by the operating system running on the processor core.
Software is responsible for guaranteeing that accesses to these resources are serialized and
logically consistent. Hardware provides a locking mechanism in the CSR to allow the
external development system to disable any attempted writes by the processor to the
breakpoint registers (setting CSR[IPW]). BDM commands must not be issued if the
MCF5307 is using the WDEBUG instruction to access debug module registers or the
resulting behavior is undefined.
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These registers, shown in Figure 5-4, are treated as 32-bit quantities, regardless of the
number of implemented bits.
31
15
31
15
7
0
31
15
31
15
0
31
15
0
31
31
15
15
AATR
Address attribute trigger register
ABLR
ABHR
Address low breakpoint register
Address high breakpoint register
BAAR
BDM address attribute register
CSR
Configuration/status register
DBR
DBMR
Data breakpoint register
Data breakpoint mask register
PBR
PBMR
PC breakpoint register
PC breakpoint mask register
TDR
Trigger definition register
0
7
0
0
0
Note: Each debug register is accessed as a 32-bit register; shaded fields above are not used (don’t care).
All debug control registers are writable from the external development system or the CPU via the
WDEBUG instruction.
CSR is write-only from the programming model. It can be read or written through the BDM port using the
RDMREG and WDMREG commands.
Figure 5-4. Debug Programming Model
These registers are accessed through the BDM port by new BDM commands, WDMREG and
RDMREG, described in Section 5.5.3.3, “Command Set Descriptions.” These commands
contain a 5-bit field, DRc, that specifies the register, as shown in Table 5-3.
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Table 5-3. BDM/Breakpoint Registers
DRc[4–0]
0x00
0x01–0x04
Register Name
Abbreviation
Initial State
Page
CSR
0x0010_0000
p. 5-10
Configuration/status register
—
—
—
0x05
BDM address attribute register
Reserved
BAAR
0x0000_0005
p. 5-9
0x06
Address attribute trigger register
AATR
0x0000_0005
p. 5-7
0x07
Trigger definition register
TDR
0x0000_0000
p. 5-14
0x08
Program counter breakpoint register
PBR
—
p. 5-13
0x09
Program counter breakpoint mask register
PBMR
—
p. 5-13
—
—
—
Address breakpoint high register
ABHR
—
p. 5-8
0x0D
Address breakpoint low register
ABLR
—
p. 5-8
0x0E
Data breakpoint register
DBR
—
p. 5-12
0x0F
Data breakpoint mask register
DBMR
—
p. 5-12
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0x0A–0x0B Reserved
0x0C
NOTE:
Debug control registers can be written by the external
development system or the CPU through the WDEBUG
instruction.
CSR is write-only from the programming model. It can be read
or written through the BDM port using the RDMREG and
WDMREG commands.
5.4.1 Address Attribute Trigger Register (AATR)
The address attribute trigger register (AATR) defines address attributes and a mask to be
matched in the trigger. The register value is compared with address attribute signals from
the processor’s local high-speed bus, as defined by the setting of the trigger definition
register (TDR).
15
Field RM
14
13
SZM
12
11
TTM
Reset
10
9
8
7
TMM
R
6
5
SZ
4
3
TT
2
1
0
TM
0000_0000_0000_0101
R/W Write only. AATR is accessible in supervisor mode as debug control register 0x06 using the WDEBUG
instruction and through the BDM port using the WDMREG command.
DRc[4–0]
0x06
Figure 5-5. Address Attribute Trigger Register (AATR)
Table 5-4 describes AATR fields.
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Table 5-4. AATR Field Descriptions
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Bits
Name
Description
15
RM
Read/write mask. Setting RM masks R in address comparisons.
14–13
SZM
Size mask. Setting an SZM bit masks the corresponding SZ bit in address comparisons.
12–11
TTM
Transfer type mask. Setting a TTM bit masks the corresponding TT bit in address comparisons.
10–8
TMM
Transfer modifier mask. Setting a TMM bit masks the corresponding TM bit in address comparisons.
7
R
Read/write. R is compared with the R/W signal of the processor’s local bus.
6–5
SZ
Size. Compared to the processor’s local bus size signals.
00 Longword
01 Byte
10 Word
11 Reserved
4–3
TT
Transfer type. Compared with the local bus transfer type signals.
00 Normal processor access
01 Reserved
10 Emulator mode access
11 Acknowledge/CPU space access
These bits also define the TT encoding for BDM memory commands. In this case, the 01 encoding
indicates an external or DMA access (for backward compatibility). These bits affect the TM bits.
2–0
TM
Transfer modifier. Compared with the local bus transfer modifier signals, which give supplemental
information for each transfer type.
TT = 00 (normal mode):
000 Explicit cache line push
001 User data access
010 User code access
011 Reserved
100 Reserved
101 Supervisor data access
110 Supervisor code access
111 Reserved
TT = 10 (emulator mode):
0xx–100 Reserved
101 Emulator mode data access
110 Emulator mode code access
111 Reserved
TT = 11 (acknowledge/CPU space transfers):
000 CPU space access
001–111 Interrupt acknowledge levels 1–7
These bits also define the TM encoding for BDM memory commands (for backward compatibility).
5.4.2 Address Breakpoint Registers (ABLR, ABHR)
The address breakpoint low and high registers (ABLR, ABHR), Figure 5-6, define regions
in the processor’s data address space that can be used as part of the trigger. These register
values are compared with the address for each transfer on the processor’s high-speed local
bus. The trigger definition register (TDR) identifies the trigger as one of three cases:
1. identically the value in ABLR
2. inside the range bound by ABLR and ABHR inclusive
3. outside that same range
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31
0
Field
Address
Reset
—
R/W Write only. ABHR is accessible in supervisor mode as debug control register 0x0C using the WDEBUG
instruction and via the BDM port using the RDMREG and WDMREG commands.
ABLR is accessible in supervisor mode as debug control register 0x0D using the WDEBUG instruction and
via the BDM port using the WDMREG command.
DRc[4–0]
0x0D (ABLR); 0x0C (ABHR)
Figure 5-6. Address Breakpoint Registers (ABLR, ABHR)
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Table 5-5 describes ABLR fields.
Table 5-5. ABLR Field Description
Bits
Name
Description
31–0
Address
Low address. Holds the 32-bit address marking the lower bound of the address breakpoint range.
Breakpoints for specific addresses are programmed into ABLR.
Table 5-6 describes ABHR fields.
Table 5-6. ABHR Field Description
Bits
Name
Description
31–0 Address High address. Holds the 32-bit address marking the upper bound of the address breakpoint range.
5.4.3 BDM Address Attribute Register (BAAR)
The BAAR defines the address space for memory-referencing BDM commands. See
Figure 5-7. The reset value of 0x5 sets supervisor data as the default address space.
7
Field
R
6
5
SZ
Reset
4
3
2
TT
1
0
TM
0000_0101
R/W Write only. BAAR[R,SZ] are loaded directly from the BDM command; BAAR[TT,TM] can be programmed as
debug control register 0x05 from the external development system. For compatibility with Rev. A, BAAR is
loaded each time AATR is written.
DRc[4–0]
0x05
Figure 5-7. BDM Address Attribute Register (BAAR)
Table 5-7 describes BAAR fields.
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Table 5-7. BAAR Field Descriptions
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Bits
Name
Description
7
R
Read/write
0 Write
1 Read
6–5
SZ
Size
00 Longword
01 Byte
10 Word
11 Reserved
4–3
TT
Transfer type. See the TT definition in Table 5-4.
2–0
TM
Transfer modifier. See the TM definition in Table 5-4.
5.4.4 Configuration/Status Register (CSR)
The configuration/status register (CSR) defines the debug configuration for the processor
and memory subsystem and contains status information from the breakpoint logic.
31
30
29
28
27
26
25
24
23
22
20
19
18
17
16
BKD
—
IPW
Reset
0000
0
0
0
0
0001
—
—
—
0
R/W1
R
R
R
R
R
R
—
—
—
R/W
10
9
3
2
1
0
15
14
13
Reset
0
R/W R/W
12
11
HRL
—
BSTAT
Field MAP TRC EMU
FOF TRG HALT BKPT
21
Field
7
6
5
4
DDC
UHE
BTB
8
—2
NPL
IPI
SSM
—
0
0
—
0
—
R
R/W
—
R/W
—
0
0
00
0
00
R/W
R/W
R/W
R/W
R/W
DRc[4–0]
0x00
1
CSR is write-only from the programming model. It can be read from and written to through the BDM port. CSR
is accessible in supervisor mode as debug control register 0x00 using the WDEBUG instruction and through
the BDM port using the RDMREG and WDMREG commands.
2 Bit 7 is reserved for Motorola use and must be written as a zero.
Figure 5-8. Configuration/Status Register (CSR)
Table 5-8 describes CSR fields.
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Table 5-8. CSR Field Descriptions
Bit
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31–28
Name
Description
BSTAT Breakpoint status. Provides read-only status information concerning hardware breakpoints. BSTAT
is cleared by a TDR write or by a CSR read when either a level-2 breakpoint is triggered or a
level-1 breakpoint is triggered and the level-2 breakpoint is disabled.
0000 No breakpoints enabled
0001 Waiting for level-1 breakpoint
0010 Level-1 breakpoint triggered
0101 Waiting for level-2 breakpoint
0110 Level-2 breakpoint triggered
27
FOF
Fault-on-fault. If FOF is set, a catastrophic halt occurred and forced entry into BDM.
26
TRG
Hardware breakpoint trigger. If TRG is set, a hardware breakpoint halted the processor core and
forced entry into BDM. Reset and the debug GO command clear TRG.
25
HALT
Processor halt. If HALT is set, the processor executed a HALT and forced entry into BDM. Reset
and the debug GO command reset HALT.
24
BKPT
Breakpoint assert. If BKPT is set, BKPT was asserted, forcing the processor into BDM. Reset and
the debug GO command clears this bit.
HRL
Hardware revision level. Indicates the level of debug module functionality. An emulator could use
this information to identify the level of functionality supported.
0000 Initial debug functionality (Revision A)
0001 Revision B (this is the only valid value for the MCF5307)
19
—
Reserved, should be cleared.
18
BKD
Breakpoint disable. Used to disable the normal BKPT input functionality and to allow the assertion
of BKPT to generate a debug interrupt.
0 Normal operation
1 BKPT is edge-sensitive: a high-to-low edge on BKPT signals a debug interrupt to the processor.
The processor makes this interrupt request pending until the next sample point, when the
exception is initiated. In the ColdFire architecture, the interrupt sample point occurs once per
instruction. There is no support for nesting debug interrupts.
17
PCD
PSTCLK disable. Setting PCD disables generation of PSTCLK, PST and DDATA outputs and
forces them to remain quiescent.
16
IPW
Inhibit processor writes. Setting IPW inhibits processor-initiated writes to the debug module’s
programming model registers. IPW can be modified only by commands from the external
development system.
15
MAP
Force processor references in emulator mode.
0 All emulator-mode references are mapped into supervisor code and data spaces.
1 The processor maps all references while in emulator mode to a special address space, TT = 10,
TM = 101 or 110.
14
TRC
Force emulation mode on trace exception. If TRC = 1, the processor enters emulator mode when a
trace exception occurs.
13
EMU
Force emulation mode. If EMU = 1, the processor begins executing in emulator mode. See
Section 5.6.1.1, “Emulator Mode.”
12–11
DDC
Debug data control. Controls operand data capture for DDATA, which displays the number of bytes
defined by the operand reference size before the actual data; byte displays 8 bits, word displays 16
bits, and long displays 32 bits (one nibble at a time across multiple clock cycles). See Table 5-2.
00 No operand data is displayed.
01 Capture all write data.
10 Capture all read data.
11 Capture all read and write data.
23–20
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Table 5-8. CSR Field Descriptions (Continued)
Bit
Name
10
UHE
User halt enable. Selects the CPU privilege level required to execute the HALT instruction.
0 HALT is a supervisor-only instruction.
1 HALT is a supervisor/user instruction.
9–8
BTB
Branch target bytes. Defines the number of bytes of branch target address DDATA displays.
00 0 bytes
01 Lower 2 bytes of the target address
10 Lower 3 bytes of the target address
11 Entire 4-byte target address
See Section 5.3.1, “Begin Execution of Taken Branch (PST = 0x5).”
7
—
6
NPL
5
IPI
4
SSM
3–0
—
Description
Reserved, should be cleared.
Non-pipelined mode. Determines whether the core operates in pipelined or mode or not.
0 Pipelined mode
1 Nonpipelined mode. The processor effectively executes one instruction at a time with no overlap.
This adds at least 5 cycles to the execution time of each instruction. Instruction folding is
disabled. Given an average execution latency of 1.6, throughput in non-pipeline mode would be
6.6, approximately 25% or less of pipelined performance.
Regardless of the NPL state, a triggered PC breakpoint is always reported before the triggering
instruction executes. In normal pipeline operation, the occurrence of an address and/or data
breakpoint trigger is imprecise. In non-pipeline mode, triggers are always reported before the next
instruction begins execution and trigger reporting can be considered precise.
An address or data breakpoint should always occur before the next instruction begins execution.
Therefore the occurrence of the address/data breakpoints should be guaranteed.
Ignore pending interrupts.
1 Core ignores any pending interrupt requests signalled while in single-instruction-step mode.
0 Core services any pending interrupt requests that were signalled while in single-step mode.
Single-step mode. Setting SSM puts the processor in single-step mode.
0 Normal mode.
1 Single-step mode. The processor halts after execution of each instruction. While halted, any
BDM command can be executed. On receipt of the GO command, the processor executes the
next instruction and halts again. This process continues until SSM is cleared.
Reserved, should be cleared.
5.4.5 Data Breakpoint/Mask Registers (DBR, DBMR)
The data breakpoint registers, Figure 5-9, specify data patterns used as part of the trigger
into debug mode. Only DBR bits not masked with a corresponding zero in DBMR are
compared with the data from the processor’s local bus, as defined in TDR.
31
0
Field
Data (DBR); Mask (DBMR)
Reset
Uninitialized
R/W DBR is accessible in supervisor mode as debug control register 0x0E, using the WDEBUG instruction and
through the BDM port using the RDMREG and WDMREG commands.
DBMR is accessible in supervisor mode as debug control register 0x0F using the WDEBUG instruction and
via the BDM port using the WDMREG command.
DRc[4–0]
0x0E (DBR), 0x0F (DBMR)
Figure 5-9. Data Breakpoint/Mask Registers (DBR and DBMR)
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Table 5-9 describes DBR fields.
Table 5-9. DBR Field Descriptions
Bits
Name
31–0
Data
Description
Data breakpoint value. Contains the value to be compared with the data value from the processor’s
local bus as a breakpoint trigger.
Table 5-10 describes DBMR fields.
Table 5-10. DBMR Field Descriptions
Bits
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31–0
Name
Mask
Description
Data breakpoint mask. The 32-bit mask for the data breakpoint trigger. Clearing a DBR bit allows
the corresponding DBR bit to be compared to the appropriate bit of the processor’s local data bus.
Setting a DBMR bit causes that bit to be ignored.
The DBR supports both aligned and misaligned references. Table 5-11 shows relationships
between processor address, access size, and location within the 32-bit data bus.
Table 5-11. Access Size and Operand Data Location
A[1:0]
Access Size
Operand Location
00
Byte
D[31:24]
01
Byte
D[23:16]
10
Byte
D[15:8]
11
Byte
D[7:0]
0x
Word
D[31:16]
1x
Word
D[15:0]
xx
Longword
D[31:0]
5.4.6 Program Counter Breakpoint/Mask Registers
(PBR, PBMR)
The PC breakpoint register (PBR) defines an instruction address for use as part of the
trigger. This register’s contents are compared with the processor’s program counter register
when TDR is configured appropriately. PBR bits are masked by clearing corresponding
PBMR bits. Results are compared with the processor’s program counter register, as defined
in TDR. Figure 5-10 shows the PC breakpoint register.
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31
1
Field
Program Counter
Reset
—
0
R/W Write. PC breakpoint register is accessible in supervisor mode using the WDEBUG instruction and through
the BDM port using the RDMREG and WDMREG commands using values shown in Section 5.5.3.3, “Command
Set Descriptions.”
DRc[4–0]
0x08
Figure 5-10. Program Counter Breakpoint Register (PBR)
Table 5-12 describes PBR fields.
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Table 5-12. PBR Field Descriptions
Bits
Name
Description
31–0 Address PC breakpoint address. The 32-bit address to be compared with the PC as a breakpoint trigger.
Figure 5-11 shows PBMR.
31
0
Field
Mask
Reset
—
R/W
Write. PBMR is accessible in supervisor mode as debug control register 0x09 using the WDEBUG
instruction and via the BDM port using the wdmreg command.
DRc[4–0]
0x09
Figure 5-11. Program Counter Breakpoint Mask Register (PBMR)
Table 5-13 describes PBMR fields.
Table 5-13. PBMR Field Descriptions
Bits
Name
31–0 Mask
Description
PC breakpoint mask. A zero in a bit position causes the corresponding PBR bit to be compared to
the appropriate PC bit. Set PBMR bits cause PBR bits to be ignored.
5.4.7 Trigger Definition Register (TDR)
The TDR, shown in Table 5-12, configures the operation of the hardware breakpoint logic
that corresponds with the ABHR/ABLR/AATR, PBR/PBMR, and DBR/DBMR registers
within the debug module. The TDR controls the actions taken under the defined conditions.
Breakpoint logic may be configured as a one- or two-level trigger. TDR[31–16] define the
second-level trigger and bits 15–0 define the first-level trigger.
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NOTE:
The debug module has no hardware interlocks, so to prevent
spurious breakpoint triggers while the breakpoint registers are
being loaded, disable TDR (by clearing TDR[29,13] before
defining triggers.
A write to TDR clears the CSR trigger status bits, CSR[BSTAT].
Section Table 5-14., “TDR Field Descriptions,” describes how to handle multiple
breakpoint conditions.
Second-Level Trigger
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31
Field
30
TRC
29
EBL
28
27
26
25
24
23
22
EDLW EDWL EDWU EDLL EDLM EDUM EDUU
Reset
21
20
DI
EAI
19
18
17
16
EAR EAL EPC
PCI
0000_0000_0000_0000
First-Level Trigger
15
Field
14
LxT
13
EBL
12
11
10
9
8
7
6
EDLW EDWL EDWU EDLL EDLM EDUM EDUU
Reset
5
4
DI
EAI
3
2
1
0
EAR EAL EPC
PCI
0000_0000_0000_0000
R/W Write only. Accessible in supervisor mode as debug control register 0x07 using the WDEBUG instruction and
through the BDM port using the WDMREG command.
DRc[4–0]
0x07
Figure 5-12. Trigger Definition Register (TDR)
Table 5-14 describes TDR fields.
Table 5-14. TDR Field Descriptions
Bits
Name
31–30
TRC
15:14
LxT
29/13
EBL
Description
Trigger response control. Determines how the processor responds to a completed trigger condition. The
trigger response is always displayed on DDATA.
00 Display on DDATA only
01 Processor halt
10 Debug interrupt
11 Reserved
Level-x trigger. This is a Rev. B function. The Level-x Trigger bit determines the logic operation for the
trigger between the PC_condition and the (Address_range & Data_condition) where the inclusion of a
Data condition is optional. The ColdFire debug architecture supports the creation of single or double-level
triggers.
TDR[15]
0 Level-2 trigger = PC_condition & Address_range & Data_condition
1 Level-2 trigger = PC_condition | (Address_range & Data_condition)
TDR[14]
0 Level-1 trigger = PC_condition & Address_range & Data_condition
1 Level-1 trigger = PC_condition | (Address_range & Data_condition)
Enable breakpoint. Global enable for the breakpoint trigger. Setting TDR[EBL] enables a breakpoint
trigger. Clearing it disables all breakpoints.
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Background Debug Mode (BDM)
Table 5-14. TDR Field Descriptions (Continued)
Bits
Name
28–22
12–6
EDx
Setting an EDx bit enables the corresponding data breakpoint condition based on the size and placement
on the processor’s local data bus. Clearing all EDx bits disables data breakpoints.
28/12
EDLW
Data longword. Entire processor’s local data bus.
27/11
EDWL
Lower data word.
26/10
EDWU Upper data word.
25/9
EDLL
Lower lower data byte. Low-order byte of the low-order word.
24/8
EDLM
Lower middle data byte. High-order byte of the low-order word.
23/7
EDUM Upper middle data byte. Low-order byte of the high-order word.
22/6
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Description
EDUU
Upper upper data byte. High-order byte of the high-order word.
21/5
DI
Data breakpoint invert. Provides a way to invert the logical sense of all the data breakpoint comparators.
This can develop a trigger based on the occurrence of a data value other than the DBR contents.
20–18/
4–2
EAx
Enable address bits. Setting an EA bit enables the corresponding address breakpoint. Clearing all three
bits disables the breakpoint.
20/4
EAI
Enable address breakpoint inverted. Breakpoint is based outside the range between ABLR and
ABHR.
19/3
EAR
Enable address breakpoint range. The breakpoint is based on the inclusive range defined by
ABLR and ABHR.
EAL
Enable address breakpoint low. The breakpoint is based on the address in the ABLR.
18/2
17/1
EPC
Enable PC breakpoint. If set, this bit enables the PC breakpoint.
16/0
PCI
Breakpoint invert. If set, this bit allows execution outside a given region as defined by PBR and PBMR to
enable a trigger. If cleared, the PC breakpoint is defined within the region defined by PBR and PBMR.
5.5 Background Debug Mode (BDM)
The ColdFire Family implements a low-level system debugger in the microprocessor
hardware. Communication with the development system is handled through a dedicated,
high-speed serial command interface. The ColdFire architecture implements the BDM
controller in a dedicated hardware module. Although some BDM operations, such as CPU
register accesses, require the CPU to be halted, other BDM commands, such as memory
accesses, can be executed while the processor is running.
5.5.1 CPU Halt
Although many BDM operations can occur in parallel with CPU operations, unrestricted
BDM operation requires the CPU to be halted. The sources that can cause the CPU to halt
are listed below in order of priority:
1. A catastrophic fault-on-fault condition automatically halts the processor.
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Background Debug Mode (BDM)
2. A hardware breakpoint can be configured to generate a pending halt condition
similar to the assertion of BKPT. This type of halt is always first made pending in
the processor. Next, the processor samples for pending halt and interrupt conditions
once per instruction. When a pending condition is asserted, the processor halts
execution at the next sample point. See Section 5.6.1, “Theory of Operation.”
3. The execution of a HALT instruction immediately suspends execution. Attempting
to execute HALT in user mode while CSR[UHE] = 0 generates a privilege violation
exception. If CSR[UHE] = 1, HALT can be executed in user mode. After HALT
executes, the processor can be restarted by serial shifting a GO command into the
debug module. Execution continues at the instruction after HALT.
4. The assertion of the BKPT input is treated as a pseudo-interrupt; that is, the halt
condition is postponed until the processor core samples for halts/interrupts. The
processor samples for these conditions once during the execution of each
instruction. If there is a pending halt condition at the sample time, the processor
suspends execution and enters the halted state.
The assertion of BKPT should be considered in the following two special cases:
•
•
After the system reset signal is negated, the processor waits for 16 processor clock
cycles before beginning reset exception processing. If the BKPT input is asserted
within eight cycles after RSTI is negated, the processor enters the halt state,
signaling halt status (0xF) on the PST outputs. While the processor is in this state,
all resources accessible through the debug module can be referenced. This is the
only chance to force the processor into emulation mode through CSR[EMU].
After system initialization, the processor’s response to the GO command depends on
the set of BDM commands performed while it is halted for a breakpoint.
Specifically, if the PC register was loaded, the GO command causes the processor to
exit halted state and pass control to the instruction address in the PC, bypassing
normal reset exception processing. If the PC was not loaded, the GO command
causes the processor to exit halted state and continue reset exception processing.
The ColdFire architecture also handles a special case of BKPT being asserted while
the processor is stopped by execution of the STOP instruction. For this case, the
processor exits the stopped mode and enters the halted state, at which point, all BDM
commands may be exercised. When restarted, the processor continues by executing
the next sequential instruction, that is, the instruction following the STOP opcode.
CSR[27–24] indicates the halt source, showing the highest priority source for multiple halt
conditions.
5.5.2 BDM Serial Interface
When the CPU is halted and PST reflects the halt status, the development system can send
unrestricted commands to the debug module. The debug module implements a synchronous
protocol using two inputs (DSCLK and DSI) and one output (DSO), where DSCLK and
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Background Debug Mode (BDM)
DSI must meet the required input setup and hold timings and the DSO is specified as a delay
relative to the rising edge of the processor clock. See Table 5-1. The development system
serves as the serial communication channel master and must generate DSCLK.
The serial channel operates at a frequency from DC to 1/5 of the processor frequency. The
channel uses full-duplex mode, where data is sent and received simultaneously by both
master and slave devices. The transmission consists of 17-bit packets composed of a
status/control bit and a 16-bit data word. As shown in Figure 5-13, all state transitions are
enabled on a rising edge of the processor clock when DSCLK is high; that is, DSI is
sampled and DSO is driven.
C1
C2
C3
C4
Freescale Semiconductor, Inc...
CPU CLK
PSTCLK
DSCLK
DSI
BDM State
Machine
DSO
Current
Current State
Next
Next State
Past
Current
Figure 5-13. BDM Serial Interface Timing
DSCLK and DSI are synchronized inputs. DSCLK acts as a pseudo clock enable and is
sampled on the rising edge of the processor CLK as well as the DSI. DSO is delayed from
the DSCLK-enabled CLK rising edge (registered after a BDM state machine state change).
All events in the debug module’s serial state machine are based on the processor clock
rising edge. DSCLK must also be sampled low (on a positive edge of CLK) between each
bit exchange. The MSB is transferred first. Because DSO changes state based on an
internally-recognized rising edge of DSCLK, DSDO cannot be used to indicate the start of
a serial transfer. The development system must count clock cycles in a given transfer.
C1–C4 are described as follows:
•
•
•
•
C1—First synchronization cycle for DSI (DSCLK is high).
C2—Second synchronization cycle for DSI (DSCLK is high).
C3—BDM state machine changes state depending upon DSI and whether the entire
input data transfer has been transmitted.
C4—DSO changes to next value.
NOTE:
A not-ready response can be ignored except during a
memory-referencing cycle. Otherwise, the debug module can
accept a new serial transfer after 32 processor clock periods.
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Background Debug Mode (BDM)
5.5.2.1 Receive Packet Format
The basic receive packet, Figure 5-14, consists of 16 data bits and 1 status bit.
16
15
0
S
Data Field [15:0]
Figure 5-14. Receive BDM Packet
Table 5-15 describes receive BDM packet fields.
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Table 5-15. Receive BDM Packet Field Description
Bits
Name
16
S
Description
Status. Indicates the status of CPU-generated messages listed below. The not-ready response can
be ignored unless a memory-referencing cycle is in progress. Otherwise, the debug module can
accept a new serial transfer after 32 processor clock periods.
S Data
Message
0 xxxx
Valid data transfer
0 0xFFFF Status OK
1 0x0000
Not ready with response; come again
1 0x0001
Error—Terminated bus cycle; data invalid
1 0xFFFF Illegal command
15–0 Data
Data. Contains the message to be sent from the debug module to the development system. The
response message is always a single word, with the data field encoded as shown above.
5.5.2.2 Transmit Packet Format
The basic transmit packet, Figure 5-15, consists of 16 data bits and 1 control bit.
16
15
0
C
D[15:0]
Figure 5-15. Transmit BDM Packet
Table 5-16 describes transmit BDM packet fields.
Table 5-16. Transmit BDM Packet Field Description
Bits
Name
16
C
15–0 Data
Description
Control. This bit is reserved. Command and data transfers initiated by the development system
should clear C.
Contains the data to be sent from the development system to the debug module.
5.5.3 BDM Command Set
Table 5-17 summarizes the BDM command set. Subsequent paragraphs contain detailed
descriptions of each command. Issuing a BDM command when the processor is accessing
debug module registers using the WDEBUG instruction causes undefined behavior.
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Background Debug Mode (BDM)
Table 5-17. BDM Command Summary
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Command
Mnemonic
Read A/D
register
RAREG/
Write A/D
register
WAREG/
Read
memory
location
Description
CPU
State1
Section
Command
(Hex)
Read the selected address or data register and
return the results through the serial interface.
Halted
5.5.3.3.1 0x218 {A/D,
Reg[2:0]}
Write the data operand to the specified address or
data register.
Halted
5.5.3.3.2 0x208 {A/D,
Reg[2:0]}
READ
Read the data at the memory location specified by
the longword address.
Steal
5.5.3.3.3 0x1900—byte
0x1940—word
0x1980—lword
Write
memory
location
WRITE
Write the operand data to the memory location
specified by the longword address.
Steal
5.5.3.3.4 0x1800—byte
0x1840—word
0x1880—lword
Dump
memory
block
DUMP
Used with READ to dump large blocks of memory.
An initial READ is executed to set up the starting
address of the block and to retrieve the first result.
A DUMP command retrieves subsequent operands.
Steal
5.5.3.3.5 0x1D00—byte
0x1D40—word
0x1D80—lword
Fill memory
block
FILL
Used with WRITE to fill large blocks of memory. An
initial WRITE is executed to set up the starting
address of the block and to supply the first operand.
A FILL command writes subsequent operands.
Steal
5.5.3.3.6 0x1C00—byte
0x1C40—word
0x1C80—lword
Resume
execution
GO
The pipeline is flushed and refilled before resuming
instruction execution at the current PC.
Halted
5.5.3.3.7 0x0C00
Perform no operation; may be used as a null
command.
Parallel
5.5.3.3.8 0x0000
Capture the current PC and display it on the
PST/DDATA output pins.
Parallel
5.5.3.3.9 0x0001
Read control RCREG
register
Read the system control register.
Halted
5.5.3.3.10 0x2980
Write control WCREG
register
Write the operand data to the system control
register.
Halted
5.5.3.3.11 0x2880
Read debug
module
register
RDMREG
Read the debug module register.
Parallel
5.5.3.3.12 0x2D {0x42
DRc[4:0]}
Write debug
module
register
WDMREG
Write the operand data to the debug module
register.
Parallel
5.5.3.3.13 0x2C {0x42
Drc[4:0]}
RDREG
WDREG
No operation NOP
Output the
current PC
SYNC_PC
1
General command effect and/or requirements on CPU operation:
- Halted. The CPU must be halted to perform this command.
- Steal. Command generates bus cycles that can be interleaved with bus accesses.
- Parallel. Command is executed in parallel with CPU activity.
2 0x4 is a three-bit field.
Unassigned command opcodes are reserved by Motorola. All unused command formats
within any revision level perform a NOP and return the illegal command response.
5.5.3.1 ColdFire BDM Command Format
All ColdFire Family BDM commands include a 16-bit operation word followed by an
optional set of one or more extension words, as shown in Figure 5-16.
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15
10
Operation
9
8
0
R/W
7
6
5
4
3
Op Size
0
0
A/D
2
0
Register
Extension Word(s)
Figure 5-16. BDM Command Format
Table 5-18 describes BDM fields.
Table 5-18. BDM Field Descriptions
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Bit
Name
Description
15–10 Operation
Specifies the command. These values are listed in Table 5-17.
9
0
Reserved
8
R/W
Direction of operand transfer.
0 Data is written to the CPU or to memory from the development system.
1 The transfer is from the CPU to the development system.
7–6
Operand
Size
Operand data size for sized operations. Addresses are expressed as 32-bit absolute values.
Note that a command performing a byte-sized memory read leaves the upper 8 bits of the
response data undefined. Referenced data is returned in the lower 8 bits of the response.
Operand Size Bit Values
00 Byte
8 bits
01 Word
16 bits
10 Longword
32 bits
11 Reserved
—
5–4
00
Reserved
3
A/D
Address/data. Determines whether the register field specifies a data or address register.
0 Indicates a data register.
1 Indicates an address register.
2–0
Register
Contains the register number in commands that operate on processor registers.
5.5.3.1.1 Extension Words as Required
Some commands require extension words for addresses and/or immediate data. Addresses
require two extension words because only absolute long addressing is permitted. Longword
accesses are forcibly longword-aligned and word accesses are forcibly word-aligned.
Immediate data can be 1 or 2 words long. Byte and word data each requires a single
extension word and longword data requires two extension words.
Operands and addresses are transferred most-significant word first. In the following
descriptions of the BDM command set, the optional set of extension words is defined as
address, data, or operand data.
5.5.3.2 Command Sequence Diagrams
The command sequence diagram in Figure 5-17 shows serial bus traffic for commands.
Each bubble represents a 17-bit bus transfer. The top half of each bubble indicates the data
the development system sends to the debug module; the bottom half indicates the debug
module’s response to the previous development system commands. Command and result
transactions overlap to minimize latency.
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Background Debug Mode (BDM)
COMMANDS TRANSMITTED TO THE DEBUG MODULE
COMMAND CODE TRANSMITTED DURING THIS CYCLE
HIGH-ORDER 16 BITS OF MEMORY ADDRESS
LOW-ORDER 16 BITS OF MEMORY ADDRESS
NONSERIAL-RELATED ACTIVITY
SEQUENCE TAKEN IF
OPERATION HAS NOT
COMPLETED
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READ (LONG)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
XXX
"ILLEGAL"
NEXT CMD
"NOT READY"
READ
MEMORY
LOCATION
XXX
"NOT READY"
XXXXX
XXX
MS RESULT
XXX
BERR
NEXT
COMMAND
CODE
NEXT CMD
LS RESULT
NEXT CMD
"NOT READY"
DATA UNUSED FROM
THIS TRANSFER
SEQUENCE TAKEN IF
ILLEGAL COMMAND
IS RECEIVED BY DEBUG MODULE
RESULTS FROM PREVIOUS COMMAND
SEQUENCE TAKEN IF BUS
ERROR OCCURS ON
MEMORY ACCESS
HIGH- AND LOW-ORDER
16 BITS OF RESULT
RESPONSES FROM THE DEBUG MODULE
Figure 5-17. Command Sequence Diagram
The sequence is as follows:
•
•
In cycle 1, the development system command is issued (READ in this example). The
debug module responds with either the low-order results of the previous command
or a command complete status of the previous command, if no results are required.
In cycle 2, the development system supplies the high-order 16 address bits. The
debug module returns a not-ready response unless the received command is decoded
as unimplemented, which is indicated by the illegal command encoding. If this
occurs, the development system should retransmit the command.
NOTE:
A not-ready response can be ignored except during a
memory-referencing cycle. Otherwise, the debug module can
accept a new serial transfer after 32 processor clock periods.
•
•
5-22
In cycle 3, the development system supplies the low-order 16 address bits. The
debug module always returns a not-ready response.
At the completion of cycle 3, the debug module initiates a memory read operation.
Any serial transfers that begin during a memory access return a not-ready response.
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Background Debug Mode (BDM)
•
Results are returned in the two serial transfer cycles after the memory access
completes. For any command performing a byte-sized memory read operation, the
upper 8 bits of the response data are undefined and the referenced data is returned in
the lower 8 bits. The next command’s opcode is sent to the debug module during the
final transfer. If a memory or register access is terminated with a bus error, the error
status (S = 1, DATA = 0x0001) is returned instead of result data.
5.5.3.3 Command Set Descriptions
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The following sections describe the commands summarized in Table 5-17.
NOTE:
The BDM status bit (S) is 0 for normally completed
commands; S = 1 for illegal commands, not-ready responses,
and transfers with bus-errors. Section 5.5.2, “BDM Serial
Interface,” describes the receive packet format.
Motorola reserves unassigned command opcodes for future expansion. Unused command
formats in any revision level perform a NOP and return an illegal command response.
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Background Debug Mode (BDM)
5.5.3.3.1 Read A/D Register (RAREG/RDREG)
Read the selected address or data register and return the 32-bit result. A bus error response
is returned if the CPU core is not halted.
Command/Result Formats:
15
Command
14
13
12
11
0x2
10
9
8
7
0x1
Result
6
5
4
0x8
3
A/D
2
1
Register
D[31:16]
D[15:0]
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Figure 5-18. RAREG/RDREG Command Format
Command Sequence:
RAREG/RDREG
???
XXX
MS RESULT
XXX
BERR
NEXT CMD
LS RESULT
NEXT CMD
"NOT READY"
Figure 5-19. RAREG/RDREG Command Sequence
Operand Data:
None
Result Data:
The contents of the selected register are returned as a longword
value, most-significant word first.
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Background Debug Mode (BDM)
5.5.3.3.2 Write A/D Register (WAREG/WDREG)
The operand longword data is written to the specified address or data register. A write alters
all 32 register bits. A bus error response is returned if the CPU core is not halted.
Command Format:
15
14
13
12
11
0x2
10
9
8
7
0x0
6
5
4
0x8
3
A/D
2
1
0
Register
D[31:16]
D[15:0]
Freescale Semiconductor, Inc...
Figure 5-20. WAREG/WDREG Command Format
Command Sequence
WDREG/WAREG
???
MS DATA
"NOT READY"
LS DATA
"NOT READY"
XXX
BERR
NEXT CMD
"NOT READY"
NEXT CMD
"CMD COMPLETE"
Figure 5-21. WAREG/WDREG Command Sequence
Operand Data
Longword data is written into the specified address or data register.
The data is supplied most-significant word first.
Result Data
Command complete status is indicated by returning 0xFFFF (with S
cleared) when the register write is complete.
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Background Debug Mode (BDM)
5.5.3.3.3 Read Memory Location (READ)
Read data at the longword address. Address space is defined by BAAR[TT,TM]. Hardware
forces low-order address bits to zeros for word and longword accesses to ensure that word
addresses are word-aligned and longword addresses are longword-aligned.
Command/Result Formats:
15
14
Byte
13
12
11
10
0x1
9
8
7
0x9
6
5
4
3
0x0
Command
2
1
0
0x0
A[31:16]
A[15:0]
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Result
Word
X
X
Command
X
X
X
0x1
X
X
X
0x9
D[7:0]
0x4
0x0
0x8
0x0
A[31:16]
A[15:0]
Result
D[15:0]
Longword Command
0x1
0x9
A[31:16]
A[15:0]
Result
D[31:16]
D[15:0]
Figure 5-22. READ Command/Result Formats
Command Sequence:
READ (B/W)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
READ
MEMORY
LOCATION
XXX
"NOT READY"
XXXCMD
NEXT
RESULT
XXX
BERR
READ (LONG)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
READ
MEMORY
LOCATION
NEXT CMD
"NOT READY"
XXX
"NOT READY"
XXX
XXX
MS RESULT
NEXT CMD
LS RESULT
XXX
BERR
NEXT CMD
"NOT READY"
Figure 5-23. READ Command Sequence
Operand Data
The only operand is the longword address of the requested location.
Result Data
Word results return 16 bits of data; longword results return 32. Bytes
are returned in the LSB of a word result, the upper byte is undefined.
0x0001 (S = 1) is returned if a bus error occurs.
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Background Debug Mode (BDM)
5.5.3.3.4 Write Memory Location (WRITE)
Write data to the memory location specified by the longword address. The address space is
defined by BAAR[TT,TM]. Hardware forces low-order address bits to zeros for word and
longword accesses to ensure that word addresses are word-aligned and longword addresses
are longword-aligned.
Command Formats:
15
14
Byte
13
12
11
10
0x1
9
8
0x8
7
6
5
4
0x0
3
2
1
0x0
A[31:16]
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A[15:0]
X
Word
X
X
0x1
X
X
X
X
X
0x8
D[7:0]
0x4
0x0
0x8
0x0
A[31:16]
A[15:0]
D[15:0]
Longword
0x1
0x8
A[31:16]
A[15:0]
D[31:16]
D[15:0]
Figure 5-24. WRITE Command Format
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Background Debug Mode (BDM)
Command Sequence:
WRITE (B/W)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
DATA
"NOT READY"
WRITE
MEMORY
LOCATION
XXX
"NOT READY"
XXX CMD
NEXT
"CMD COMPLETE"
XXX
BERR
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NEXT CMD
"NOT READY"
WRITE (LONG)
???
MS ADDR
"NOT READY"
LS ADDR
"NOT READY"
MS DATA
"NOT READY"
LS DATA
"NOT READY"
WRITE
MEMORY
LOCATION
XXX
"NOT READY"
XXX CMD
NEXT
"CMD COMPLETE"
XXX
BERR
NEXT CMD
"NOT READY"
Figure 5-25. WRITE Command Sequence
Operand Data
This two-operand instruction requires a longword absolute address
that specifies a location to which the data operand is to be written.
Byte data is sent as a 16-bit word, justified in the LSB; 16- and 32-bit
operands are sent as 16 and 32 bits, respectively
Result Data
Command complete status is indicated by returning 0xFFFF (with S
cleared) when the register write is complete. A value of 0x0001 (with
S set) is returned if a bus error occurs.
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Background Debug Mode (BDM)
5.5.3.3.5 Dump Memory Block (DUMP)
is used with the READ command to access large blocks of memory. An initial READ
is executed to set up the starting address of the block and to retrieve the first result. If an
initial READ is not executed before the first DUMP, an illegal command response is returned.
The DUMP command retrieves subsequent operands. The initial address is incremented by
the operand size (1, 2, or 4) and saved in a temporary register. Subsequent DUMP commands
use this address, perform the memory read, increment it by the current operand size, and
store the updated address in the temporary register.
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DUMP
NOTE:
DUMP does not check for a valid address; it is a valid command
only when preceded by NOP, READ, or another DUMP command.
Otherwise, an illegal command response is returned. NOP can
be used for intercommand padding without corrupting the
address pointer.
The size field is examined each time a DUMP command is processed, allowing the operand
size to be dynamically altered.
Command/Result Formats:
Byte
14
X
X
Command
Result
Word
15
Command
13
12
11
10
X
X
X
X
0x1
8
X
X
7
0xD
0x1
6
5
4
3
0x0
0xD
Result
Longword Command
9
2
1
0
0x0
D[7:0]
0x4
0x0
0x8
0x0
D[15:0]
0x1
0xD
Result
D[31:16]
D[15:0]
Figure 5-26.
DUMP
Command/Result Formats
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Background Debug Mode (BDM)
Command Sequence:
READ
MEMORY
LOCATION
DUMP (B/W)
???
XXX
"NOT READY"
NEXT CMD
RESULT
XXX
"ILLEGAL"
READ
MEMORY
LOCATION
DUMP (LONG)
???
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NEXT CMD
"NOT READY"
XXX
"ILLEGAL"
XXX
BERR
NEXT CMD
"NOT READY"
XXX
"NOT READY"
NEXT CMD
"NOT READY"
NEXT CMD
MS RESULT
NEXT CMD
LS RESULT
XXX
BERR
NEXT CMD
"NOT READY"
Figure 5-27. DUMP Command Sequence
Operand Data:
None
Result Data:
Requested data is returned as either a word or longword. Byte data is
returned in the least-significant byte of a word result. Word results
return 16 bits of significant data; longword results return 32 bits. A
value of 0x0001 (with S set) is returned if a bus error occurs.
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Background Debug Mode (BDM)
5.5.3.3.6 Fill Memory Block (FILL)
A FILL command is used with the WRITE command to access large blocks of memory. An
initial WRITE is executed to set up the starting address of the block and to supply the first
operand. The FILL command writes subsequent operands. The initial address is incremented
by the operand size (1, 2, or 4) and saved in a temporary register after the memory write.
Subsequent FILL commands use this address, perform the write, increment it by the current
operand size, and store the updated address in the temporary register.
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If an initial WRITE is not executed preceding the first FILL command, the illegal command
response is returned.
NOTE:
The FILL command does not check for a valid address—FILL is
a valid command only when preceded by another FILL, a NOP,
or a WRITE command. Otherwise, an illegal command response
is returned. The NOP command can be used for intercommand
padding without corrupting the address pointer.
The size field is examined each time a FILL command is processed, allowing the operand
size to be altered dynamically.
Command Formats:
15
14
Byte
X
Word
13
12
11
10
0x1
X
9
8
7
0xC
X
X
X
0x1
X
6
5
4
3
0x0
X
X
0xC
2
1
0
0x0
D[7:0]
0x4
0x0
0x8
0x0
D[15:0]
Longword
0x1
0xC
D[31:16]
D[15:0]
Figure 5-28.
FILL
Command Format
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Background Debug Mode (BDM)
Command Sequence:
FILL
FILL(LONG)
(B/W)
???
MS DATA
"NOT READY"
XXX
"ILLEGAL"
LS DATA
"NOT READY"
WRITE
MEMORY
LOCATION
XXX
"NOT READY"
NEXT CMD
"CMD COMPLETE"
NEXT CMD
"NOT READY"
XXX
BERR
Freescale Semiconductor, Inc...
FILL(LONG)
(B/W)
FILL
???
DATA
"NOT READY"
WRITE
MEMORY
LOCATION
XXX
"ILLEGAL"
NEXT CMD
"NOT READY"
NEXT CMD
"NOT READY"
XXX
"NOT READY"
NEXT CMD
"CMD COMPLETE"
XXX
BERR
NEXT CMD
"NOT READY"
Figure 5-29. FILL Command Sequence
Operand Data:
A single operand is data to be written to the memory location. Byte
data is sent as a 16-bit word, justified in the least-significant byte; 16and 32-bit operands are sent as 16 and 32 bits, respectively.
Result Data:
Command complete status (0xFFFF) is returned when the register
write is complete. A value of 0x0001 (with S set) is returned if a bus
error occurs.
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Background Debug Mode (BDM)
5.5.3.3.7 Resume Execution (GO)
The pipeline is flushed and refilled before normal instruction execution resumes.
Prefetching begins at the current address in the PC and at the current privilege level. If any
register (such as the PC or SR) is altered by a BDM command while the processor is halted,
the updated value is used when prefetching resumes. If a GO command is issued and the
CPU is not halted, the command is ignored.
15
14
13
12
11
10
0x0
9
0xC
8
7
6
5
4
0x0
3
2
1
0
0x0
Figure 5-30. GO Command Format
Freescale Semiconductor, Inc...
Command Sequence:
GO
???
NEXT CMD
"CMD COMPLETE"
Figure 5-31. GO Command Sequence
Operand Data:
None
Result Data:
The command-complete response (0xFFFF) is returned during the
next shift operation.
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Background Debug Mode (BDM)
5.5.3.3.8 No Operation (NOP)
NOP
performs no operation and may be used as a null command where required.
Command Formats:
15
12
11
8
0x0
0x0
7
4
0x0
3
0
0x0
Figure 5-32. NOP Command Format
Command Sequence:
Freescale Semiconductor, Inc...
NOP
???
NEXT CMD
"CMD COMPLETE"
Figure 5-33. NOP Command Sequence
Operand Data:
None
Result Data:
The command-complete response, 0xFFFF (with S cleared), is
returned during the next shift operation.
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Background Debug Mode (BDM)
5.5.3.3.9 Synchronize PC to the PST/DDATA Lines (SYNC_PC)
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The SYNC_PC command captures the current PC and displays it on the PST/DDATA
outputs. After the debug module receives the command, it sends a signal to the ColdFire
processor that the current PC must be displayed. The processor then forces an instruction
fetch at the next PC with the address being captured in the DDATA logic under control of
CSR[BTB]. The specific sequence of PST and DDATA values is as follows:
1. Debug signals a SYNC_PC command is pending.
2. CPU completes the current instruction.
3. CPU forces an instruction fetch to the next PC, generates a PST = 0x5 value
indicating a taken branch and signals the capture of DDATA.
4. The instruction address corresponding to the PC is captured.
5. The PST marker (0x9–0xB) is generated and displayed as defined by CSR[BTB]
followed by the captured PC address.
The SYNC_PC command can be used to dynamically access the PC for performance
monitoring. The execution of this command is considerably less obtrusive to the real-time
operation of an application than a HALT-CPU/READ-PC/RESUME command sequence.
Command Formats:
15
12
11
0x0
8
0x0
7
4
0x0
3
0
0x1
Figure 5-34. SYNC_PC Command Format
Command Sequence:
SYNC_PC
NOP
???
NEXT CMD
"CMD COMPLETE"
Figure 5-35. SYNC_PC Command Sequence
Operand Data:
None
Result Data:
Command complete status (0xFFFF) is returned when the register
write is complete.
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Background Debug Mode (BDM)
5.5.3.3.10 Read Control Register (RCREG)
Read the selected control register and return the 32-bit result. Accesses to the
processor/memory control registers are always 32 bits wide, regardless of register width.
The second and third words of the command form a 32-bit address, which the debug
module uses to generate a special bus cycle to access the specified control register. The
12-bit Rc field is the same as that used by the MOVEC instruction.
Command/Result Formats:
15
Freescale Semiconductor, Inc...
Command
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0x2
0x9
0x8
0x0
0x0
0x0
0x0
0x0
0x0
0
Rc
Result
D[31:16]
D[15:0]
Figure 5-36. RCREG Command/Result Formats
Rc encoding:
Table 5-19. Control Register Map
Rc
Register Definition
Rc
Register Definition
0x002
Cache control register (CACR)
0x805
MAC mask register (MASK)1
0x004
Access control register 0 (ACR0)
0x806
MAC accumulator (ACC)1
0x005
Access control register 1 (ACR1)
0x80E
Status register (SR)
0x801
Vector base register (VBR)
0x80F
Program register (PC)
0x804
MAC status register (MACSR)1
0xC04
RAM base address register (RAMBAR)
1
Available if the optional MAC unit is present.
Command Sequence:
RCREG
???
MS ADDR
EXT
WORD
"NOT READY"
MS ADDR
EXT
WORD
"NOT READY"
READ
CONTROL
MEMORY
REGISTER
LOCATION
XXX
"NOT READY"
XXX
MS RESULT
NEXT CMD
LS RESULT
XXX
BERR
NEXT CMD
"NOT READY"
Figure 5-37. RCREG Command Sequence
Operand Data:
The only operand is the 32-bit Rc control register select field.
Result Data:
Control register contents are returned as a longword,
most-significant word first. The implemented portion of registers
smaller than 32 bits is guaranteed correct; other bits are undefined.
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Background Debug Mode (BDM)
5.5.3.3.11 Write Control Register (WCREG)
The operand (longword) data is written to the specified control register. The write alters all
32 register bits.
Command/Result Formats:
15
Command
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0x2
0x8
0x8
0x0
0x0
0x0
0x0
0x0
0x0
0
Rc
Result
D[31:16]
Freescale Semiconductor, Inc...
D[15:0]
Figure 5-38. WCREG Command/Result Formats
Command Sequence:
WCREG
???
MS ADDR
EXT
WORD
"NOT READY"
MS ADDR
EXT
WORD
"NOT READY"
MS DATA
"NOT READY"
LS DATA
"NOT READY"
WRITE
WRITE
CONTROL
MEMORY
REGISTER
LOCATION
XXX
"NOT READY"
XXX CMD
NEXT
"CMD COMPLETE"
XXX
BERR
NEXT CMD
"NOT READY"
Figure 5-39. WCREG Command Sequence
Operand Data:
This instruction requires two longword operands. The first selects the
register to which the operand data is to be written; the second
contains the data.
Result Data:
Successful write operations return 0xFFFF. Bus errors on the write
cycle are indicated by the setting of bit 16 in the status message and
by a data pattern of 0x0001.
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Background Debug Mode (BDM)
5.5.3.3.12 Read Debug Module Register (RDMREG)
Read the selected debug module register and return the 32-bit result. The only valid register
selection for the RDMREG command is CSR (DRc = 0x00). Note that this read of the CSR
clears the trigger status bits (CSR[BSTAT]) if either a level-2 breakpoint has been triggered
or a level-1 breakpoint has been triggered and no level-2 breakpoint has been enabled.
Command/Result Formats:
15
Command
14
13
12
11
10
0x2
9
8
7
6
5
4
3
0x41
0xD
Result
2
1
0
DRc
D[31:16]
Freescale Semiconductor, Inc...
D[15:0]
Figure 5-40.
1
RDMREG BDM
Command/Result Formats
Note 0x4 is a 3-bit field
Table 5-20 shows the definition of DRc encoding.
Table 5-20. Definition of DRc Encoding—Read
DRc[4:0]
Debug Register Definition
Mnemonic
Initial State
Page
0x00
Configuration/Status
CSR
0x0
p. 5-10
0x01–0x1F
Reserved
—
—
—
Command Sequence:
RDMREG
???
XXX
MS RESULT
NEXT CMD
LS RESULT
XXX
"ILLEGAL"
NEXT CMD
"NOT READY"
Figure 5-41. RDMREG Command Sequence
Operand Data:
None
Result Data:
The contents of the selected debug register are returned as a
longword value. The data is returned most-significant word first.
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Real-Time Debug Support
5.5.3.3.13 Write Debug Module Register (WDMREG)
The operand (longword) data is written to the specified debug module register. All 32 bits
of the register are altered by the write. DSCLK must be inactive while the debug module
register writes from the CPU accesses are performed using the WDEBUG instruction.
Command Format:
Figure 5-42. WDMREG BDM Command Format
15
14
13
12
11
0x2
10
9
8
7
6
5
4
3
0x41
0xC
2
1
0
DRc
D[31:16]
Freescale Semiconductor, Inc...
D[15:0]
1
Note: 0x4 is a three-bit field
Table 5-3 shows the definition of the DRc write encoding.
Command Sequence:
WDMREG
???
MS DATA
"NOT READY"
LS DATA
"NOT READY"
XXX
"ILLEGAL"
NEXT CMD
"NOT READY"
NEXT CMD
"CMD COMPLETE"
Figure 5-43. WDMREG Command Sequence
Operand Data:
Longword data is written into the specified debug register. The data
is supplied most-significant word first.
Result Data:
Command complete status (0xFFFF) is returned when register write
is complete.
5.6 Real-Time Debug Support
The ColdFire Family provides support debugging real-time applications. For these types of
embedded systems, the processor must continue to operate during debug. The foundation
of this area of debug support is that while the processor cannot be halted to allow
debugging, the system can generally tolerate small intrusions into the real-time operation.
The debug module provides three types of breakpoints—PC with mask, operand address
range, and data with mask. These breakpoints can be configured into one- or two-level
triggers with the exact trigger response also programmable. The debug module
programming model can be written from either the external development system using the
debug serial interface or from the processor’s supervisor programming model using the
WDEBUG instruction. Only CSR is readable using the external development system.
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Real-Time Debug Support
5.6.1 Theory of Operation
Breakpoint hardware can be configured to respond to triggers in several ways. The response
desired is programmed into TDR. As shown in Table 5-21, when a breakpoint is triggered,
an indication (CSR[BSTAT]) is provided on the DDATA output port when it is not
displaying captured processor status, operands, or branch addresses.
Table 5-21. DDATA[3:0]/CSR[BSTAT] Breakpoint Response
Freescale Semiconductor, Inc...
DDATA[3:0]/CSR[BSTAT] 1
1
Breakpoint Status
0000/0000
No breakpoints enabled
0010/0001
Waiting for level-1 breakpoint
0100/0010
Level-1 breakpoint triggered
1010/0101
Waiting for level-2 breakpoint
1100/0110
Level-2 breakpoint triggered
Encodings not shown are reserved for future use.
The breakpoint status is also posted in CSR. Note that CSR[BSTAT] is cleared by a CSR
read when either a level-2 breakpoint is triggered or a level-1 breakpoint is triggered and a
level-2 breakpoint is not enabled. Status is also cleared by writing to TDR.
BDM instructions use the appropriate registers to load and configure breakpoints. As the
system operates, a breakpoint trigger generates the response defined in TDR.
PC breakpoints are treated in a precise manner—exception recognition and processing are
initiated before the excepting instruction is executed. All other breakpoint events are
recognized on the processor’s local bus, but are made pending to the processor and sampled
like other interrupt conditions. As a result, these interrupts are imprecise.
In systems that tolerate the processor being halted, a BDM-entry can be used. With
TDR[TRC] = 01, a breakpoint trigger causes the core to halt (PST = 0xF).
If the processor core cannot be halted, the debug interrupt can be used. With this
configuration, TDR[TRC] = 10, the breakpoint trigger becomes a debug interrupt to the
processor, which is treated higher than the nonmaskable level-7 interrupt request. As with
all interrupts, it is made pending until the processor reaches a sample point, which occurs
once per instruction. Again, the hardware forces the PC breakpoint to occur before the
targeted instruction executes. This is possible because the PC breakpoint is enabled when
interrupt sampling occurs. For address and data breakpoints, reporting is considered
imprecise because several instructions may execute after the triggering address or data is
detected.
As soon as the debug interrupt is recognized, the processor aborts execution and initiates
exception processing. This event is signaled externally by the assertion of a unique PST
value (PST = 0xD) for multiple cycles. The core enters emulator mode when exception
processing begins. After the standard 8-byte exception stack is created, the processor
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Real-Time Debug Support
fetches a unique exception vector, 12, from the vector table.
Execution continues at the instruction address in the vector corresponding to the breakpoint
triggered. All interrupts are ignored while the processor is in emulator mode. The debug
interrupt handler can use supervisor instructions to save the necessary context such as the
state of all program-visible registers into a reserved memory area.
Freescale Semiconductor, Inc...
When debug interrupt operations complete, the RTE instruction executes and the processor
exits emulator mode. After the debug interrupt handler completes execution, the external
development system can use BDM commands to read the reserved memory locations.
The generation of another debug interrupt during the first instruction after the RTE exits
emulator mode is inhibited. This behavior is consistent with the existing logic involving
trace mode where the first instruction executes before another trace exception is generated.
Thus, all hardware breakpoints are disabled until the first instruction after the RTE
completes execution, regardless of the programmed trigger response.
5.6.1.1 Emulator Mode
Emulator mode is used to facilitate non-intrusive emulator functionality. This mode can be
entered in three different ways:
•
•
•
Setting CSR[EMU] forces the processor into emulator mode. EMU is examined
only if RSTI is negated and the processor begins reset exception processing. It can
be set while the processor is halted before reset exception processing begins. See
Section 5.5.1, “CPU Halt.”
A debug interrupt always puts the processor in emulation mode when debug
interrupt exception processing begins.
Setting CSR[TRC] forces the processor into emulation mode when trace exception
processing begins.
While operating in emulation mode, the processor exhibits the following properties:
•
•
All interrupts are ignored, including level-7 interrupts.
If CSR[MAP] = 1, all caching of memory and the SRAM module are disabled. All
memory accesses are forced into a specially mapped address space signaled by
TT = 0x2, TM = 0x5 or 0x6. This includes stack frame writes and the vector fetch
for the exception that forced entry into this mode.
The RTE instruction exits emulation mode. The processor status output port provides a
unique encoding for emulator mode entry (0xD) and exit (0x7).
5.6.2 Concurrent BDM and Processor Operation
The debug module supports concurrent operation of both the processor and most BDM
commands. BDM commands may be executed while the processor is running, except those
following operations that access processor/memory registers:
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Motorola-Recommended BDM Pinout
•
•
Read/write address and data registers
Read/write control registers
For BDM commands that access memory, the debug module requests the processor’s local
bus. The processor responds by stalling the instruction fetch pipeline and waiting for
current bus activity to complete before freeing the local bus for the debug module to
perform its access. After the debug module bus cycle, the processor reclaims the bus.
Freescale Semiconductor, Inc...
Breakpoint registers must be carefully configured in a development system if the processor
is executing. The debug module contains no hardware interlocks, so TDR should be
disabled while breakpoint registers are loaded, after which TDR can be written to define the
exact trigger. This prevents spurious breakpoint triggers.
Because there are no hardware interlocks in the debug unit, no BDM operations are allowed
while the CPU is writing the debug’s registers (DSCLK must be inactive).
5.7 Motorola-Recommended BDM Pinout
The ColdFire BDM connector, Figure 5-44, is a 26-pin Berg connector arranged 2 x 13.
Developer reserved 1
1
2
BKPT
GND
3
4
DSCLK
GND
5
6
Developer reserved 1
RESET
7
8
DSI
Pad-Voltage2
9
10
DSO
GND
11
12
PST3
PST2
13
14
PST1
PST0
15
16
DDATA3
DDATA2
17
18
DDATA1
DDATA0
19
20
GND
Motorola reserved
21
22
Motorola reserved
GND
23
24
CLK_CPU
Core-Voltage
25
26
TA
1Pins reserved for BDM
2Supplied by target
developer use.
Figure 5-44. Recommended BDM Connector
5.8 Processor Status, DDATA Definition
This section specifies the ColdFire processor and debug module’s generation of the
processor status (PST) and debug data (DDATA) output on an instruction basis. In general,
the PST/DDATA output for an instruction is defined as follows:
PST = 0x1, {PST = [0x89B], DDATA= operand}
where the {...} definition is optional operand information defined by the setting of the CSR.
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Processor Status, DDATA Definition
The CSR provides capabilities to display operands based on reference type (read, write, or
both). Additionally, for certain change-of-flow branch instructions, another CSR field
provides the capability to display {0x2, 0x3, 0x4} bytes of the target instruction address.
For both situations, an optional PST value {0x8, 0x9, 0xB} provides the marker identifying
the size and presence of valid data on the DDATA output.
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5.8.1 User Instruction Set
Table 5-22 shows the PST/DDATA specification for user-mode instructions. Rn represents
any {Dn, An} register. In this definition, the ‘y’ suffix generally denotes the source and ‘x’
denotes the destination operand. For a given instruction, the optional operand data is
displayed only for those effective addresses referencing memory. The ‘DD’ nomenclature
refers to the DDATA outputs.
Table 5-22. PST/DDATA Specification for User-Mode Instructions
Instruction
Operand Syntax
PST/DDATA
add.l
y,Rx
PST = 0x1, {PST = 0xB, DD = source operand}
add.l
Dy,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
addi.l
#imm,Dx
PST = 0x1
addq.l
#imm,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
addx.l
Dy,Dx
PST = 0x1
and.l
y,Dx
PST = 0x1, {PST = 0xB, DD = source operand}
and.l
Dy,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
andi.l
#imm,Dx
PST = 0x1
asl.l
{Dy,#imm},Dx
PST = 0x1
asr.l
{Dy,#imm},Dx
PST = 0x1
bcc.{b,w}
if taken, then PST = 0x5, else PST = 0x1
bchg
#imm,x
PST = 0x1, {PST = 0x8, DD = source}, {PST = 0x8, DD = destination}
bchg
Dy,x
PST = 0x1, {PST = 0x8, DD = source}, {PST = 0x8, DD = destination}
bclr
#imm,x
PST = 0x1, {PST = 0x8, DD = source}, {PST = 0x8, DD = destination}
bclr
Dy,x
PST = 0x1, {PST = 0x8, DD = source}, {PST = 0x8, DD = destination}
bra.{b,w}
PST = 0x5
bset
#imm,x
PST = 0x1, {PST = 0x8, DD = source}, {PST = 0x8, DD = destination}
bset
Dy,x
PST = 0x1, {PST = 0x8, DD = source}, {PST = 0x8, DD = destination}
bsr.{b,w}
PST = 0x5, {PST = 0xB, DD = destination operand}
btst
#imm,x
PST = 0x1, {PST = 0x8, DD = source operand}
btst
Dy,x
PST = 0x1, {PST = 0x8, DD = source operand}
clr.b
x
PST = 0x1, {PST = 0x8, DD = destination operand}
clr.l
x
PST = 0x1, {PST = 0xB, DD = destination operand}
clr.w
x
PST = 0x1, {PST = 0x9, DD = destination operand}
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Processor Status, DDATA Definition
Table 5-22. PST/DDATA Specification for User-Mode Instructions (Continued)
Freescale Semiconductor, Inc...
Instruction
Operand Syntax
PST/DDATA
cmp.l
y,Rx
PST = 0x1, {PST = 0xB, DD = source operand}
cmpi.l
#imm,Dx
PST = 0x1
divs.l
y,Dx
PST = 0x1, {PST = 0xB, DD = source operand}
divs.w
y,Dx
PST = 0x1, {PST = 0x9, DD = source operand}
divu.l
y,Dx
PST = 0x1, {PST = 0xB, DD = source operand}
divu.w
y,Dx
PST = 0x1, {PST = 0x9, DD = source operand}
eor.l
Dy,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
eori.l
#imm,Dx
PST = 0x1
ext.l
Dx
PST = 0x1
ext.w
Dx
PST = 0x1
extb.l
Dx
PST = 0x1
jmp
x
PST = 0x5, {PST = [0x9AB], DD = target address} 1
jsr
x
PST = 0x5, {PST = [0x9AB], DD = target address},
{PST = 0xB , DD = destination operand}1
lea
y,Ax
PST = 0x1
link.w
Ay,#imm
PST = 0x1, {PST = 0xB, DD = destination operand}
lsl.l
{Dy,#imm},Dx
PST = 0x1
lsr.l
{Dy,#imm},Dx
PST = 0x1
mac.l
PST = 0x1
mac.l
Ry,Rx
mac.l
Ry,Rx,ea,Rw
PST = 0x1
PST = 0x1, {PST = 0xB, DD = source operand}
mac.w
PST = 0x1
mac.w
Ry,Rx
mac.w
Ry,Rx,ea,Rw
PST = 0x1, {PST = 0xB, DD = source operand}
move.b
y,x
PST = 0x1, {PST = 0x8, DD = source}, {PST = 0x8, DD = destination}
move.l
y,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
move.l
y,ACC
PST = 0x1
move.l
y,MACSR
PST = 0x1
move.l
y,MASK
PST = 0x1
move.l
ACC,Rx
PST = 0x1
move.l
MACSR,CCR
PST = 0x1
move.l
MACSR,Rx
PST = 0x1
move.l
MASK,Rx
PST = 0x1
move.w
y,x
PST = 0x1, {PST = 0x9, DD = source}, {PST = 0x9, DD = destination}
move.w
CCR,Dx
PST = 0x1
move.w
{Dy,#imm},CCR
PST = 0x1
5-44
PST = 0x1
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Processor Status, DDATA Definition
Table 5-22. PST/DDATA Specification for User-Mode Instructions (Continued)
Freescale Semiconductor, Inc...
Instruction
Operand Syntax
PST/DDATA
movem.l
#list,x
PST = 0x1, {PST = 0xB, DD = destination},... 2
movem.l
y,#list
PST = 0x1, {PST = 0xB, DD = source},... 2
moveq
#imm,Dx
PST = 0x1
msac.l
Ry,Rx
PST = 0x1
msac.l
Ry,Rx,ea,Rw
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
msac.w
Ry,Rx
PST = 0x1
msac.w
Ry,Rx,ea,Rw
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
muls.l
y,Dx
PST = 0x1, {PST = 0xB, DD = source operand}
muls.w
y,Dx
PST = 0x1, {PST = 0x9, DD = source operand}
mulu.l
y,Dx
PST = 0x1, {PST = 0xB, DD = source operand}
mulu.w
y,Dx
PST = 0x1, {PST = 0x9, DD = source operand}
neg.l
Dx
PST = 0x1
negx.l
Dx
nop
PST = 0x1
PST = 0x1
not.l
Dx
PST = 0x1
or.l
y,Dx
PST = 0x1, {PST = 0xB, DD = source operand}
or.l
Dy,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
ori.l
#imm,Dx
PST = 0x1
pea
y
PST = 0x1, {PST = 0xB, DD = destination operand}
pulse
PST = 0x4
rems.l
y,Dx:Dw
PST = 0x1, {PST = 0xB, DD = source operand}
remu.l
y,Dx:Dw
PST = 0x1, {PST = 0xB, DD = source operand}
rts
PST = 0x1, {PST = 0xB, DD = source operand},
PST = 0x5, {PST = [0x9AB], DD = target address}
scc
Dx
PST = 0x1
sub.l
y,Rx
PST = 0x1, {PST = 0xB, DD = source operand}
sub.l
Dy,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
subi.l
#imm,Dx
PST = 0x1
subq.l
#imm,x
PST = 0x1, {PST = 0xB, DD = source}, {PST = 0xB, DD = destination}
subx.l
Dy,Dx
PST = 0x1
swap
Dx
PST = 0x1
trap
#imm
PST = 0x1 3
trapf
PST = 0x1
tst.b
x
PST = 0x1, {PST = 0x8, DD = source operand}
tst.l
x
PST = 0x1, {PST = 0xB, DD = source operand}
tst.w
x
PST = 0x1, {PST = 0x9, DD = source operand}
Chapter 5. Debug Support
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Processor Status, DDATA Definition
Table 5-22. PST/DDATA Specification for User-Mode Instructions (Continued)
Instruction
Operand Syntax
PST/DDATA
unlk
Ax
PST = 0x1, {PST = 0xB, DD = destination operand}
wddata.b
y
PST = 0x4, {PST = 0x8, DD = source operand
wddata.l
y
PST = 0x4, {PST = 0xB, DD = source operand
wddata.w
y
PST = 0x4, {PST = 0x9, DD = source operand
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1
For JMP and JSR instructions, the optional target instruction address is displayed only for those effective
address fields defining variant addressing modes. This includes the following x values: (An), (d16,An),
(d8,An,Xi), (d8,PC,Xi).
2 For Move Multiple instructions (MOVEM), the processor automatically generates line-sized transfers if the
operand address reaches a 0-modulo-16 boundary and there are four or more registers to be transferred. For
these line-sized transfers, the operand data is never captured nor displayed, regardless of the CSR value.
The automatic line-sized burst transfers are provided to maximize performance during these sequential
memory access operations.
3 During normal exception processing, the PST output is driven to a 0xC indicating the exception processing
state. The exception stack write operands, as well as the vector read and target address of the exception
handler may also be displayed.
Exception Processing
PST = 0xC, {PST
{PST
{PST
PST = 0x5, {PST
=
=
=
=
0xB, DD = destination},// stack frame
0xB, DD = destination},// stack frame
0xB, DD = source},// vector read
[0x9AB], DD = target}// PC of handler
The PST/DDATA specification for the reset exception is shown below:
Exception Processing PST = 0xC,
PST = 0x5,{PST = [0x9AB], DD = target}// PC of handler
The initial references at address 0 and 4 are never captured nor displayed since these
accesses are treated as instruction fetches.
For all types of exception processing, the PST = 0xC value is driven at all times, unless the
PST output is needed for one of the optional marker values or for the taken branch indicator
(0x5).
5.8.2 Supervisor Instruction Set
The supervisor instruction set has complete access to the user mode instructions plus the
opcodes shown below. The PST/DDATA specification for these opcodes is shown in
Table 5-23.
Table 5-23. PST/DDATA Specification for Supervisor-Mode Instructions
Instruction
Operand Syntax
PSTDDATA
cpushl
PST = 0x1
halt
PST = 0x1,
PST = 0xF
move.w
SR,Dx
PST = 0x1
move.w
{Dy,#imm},SR
PST = 0x1, {PST = 3}
5-46
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Processor Status, DDATA Definition
Table 5-23. PST/DDATA Specification for Supervisor-Mode Instructions
Instruction
movec
Operand Syntax
Ry,Rc
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rte
PSTDDATA
PST = 0x1
PST = 0x7, {PST = 0xB, DD = source operand}, {PST = 3},{ PST =0xB,
DD =source operand},
PST = 0x5, {[PST = 0x9AB], DD = target address}
stop
#imm
PST = 0x1,
PST = 0xE
wdebug
y
PST = 0x1, {PST = 0xB, DD = source, PST = 0xB, DD = source}
The move-to-SR and RTE instructions include an optional PST = 0x3 value, indicating an
entry into user mode. Additionally, if the execution of a RTE instruction returns the
processor to emulator mode, a multiple-cycle status of 0xD is signaled.
Similar to the exception processing mode, the stopped state (PST = 0xE) and the halted
state (PST = 0xF) display this status throughout the entire time the ColdFire processor is in
the given mode.
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Processor Status, DDATA Definition
5-48
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Part II
System Integration Module (SIM)
Intended Audience
Part II is intended for users who need to understand the interface between the ColdFire core
processor complex, described in Part I, and internal peripheral devices, described in
Part III. It includes a general description of the SIM and individual chapters that describe
components of the SIM, such as the phase-lock loop (PLL) timing source, interrupt
controller for both on-chip and external peripherals, configuration and operation of chip
selects, and the SDRAM controller.
Contents
Part II contains the following chapters:
•
•
•
•
•
•
Chapter 6, “SIM Overview,” describes the SIM programming model, bus
arbitration, and system-protection functions for the MCF5307.
Chapter 7, “Phase-Locked Loop (PLL),” describes configuration and operation of
the PLL module. It describes in detail the registers and signals that support the PLL
implementation.
Chapter 8, “I2C Module,” describes the MCF5307 I2C module, including I2C
protocol, clock synchronization, and the registers in the I2C programing model. It
also provides extensive programming examples.
Chapter 9, “Interrupt Controller,” describes operation of the interrupt controller
portion of the SIM. Includes descriptions of the registers in the interrupt controller
memory map and the interrupt priority scheme.
Chapter 10, “Chip-Select Module,” describes the MCF5307 chip-select
implementation, including the operation and programming model, which includes
the chip-select address, mask, and control registers.
Chapter 11, “Synchronous/Asynchronous DRAM Controller Module,” describes
configuration and operation of the synchronous/asynchronous DRAM controller
component of the SIM. It begins with a general description and brief glossary, and
Part II. System Integration Module (SIM)
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includes a description of signals involved in DRAM operations. The remainder of
the chapter is divided between descriptions of asynchronous and synchronous
operations.
Suggested Reading
The following literature may be helpful with respect to the topics in Part II:
The I2C Bus Specification, Version 2.1 (January 2000)
•
Freescale Semiconductor, Inc...
Acronyms and Abbreviations
Table II-i contains acronyms and abbreviations are used in Part II.
Table II-i. Acronyms and Abbreviated Terms
Term
Meaning
ADC
Analog-to-digital conversion
BDM
Background debug mode
CODEC
Code/decode
DAC
Digital-to-analog conversion
DMA
Direct memory access
DSP
Digital signal processing
EDO
Extended data output (DRAM)
FIFO
First-in, first-out
GPIO
I2C
Inter-integrated circuit
IEEE
Institute for Electrical and Electronics Engineers
IPL
Interrupt priority level
JEDEC
Joint Electron Device Engineering Council
LIFO
Last-in, first-out
LRU
Least recently used
LSB
Least-significant byte
lsb
Least-significant bit
MBAR
Memory base address register
MSB
Most-significant byte
msb
Most-significant bit
Mux
Multiplex
II-ii
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Table II-i. Acronyms and Abbreviated Terms (Continued)
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Term
Meaning
NOP
No operation
PCLK
Processor clock
PLL
Phase-locked loop
POR
Power-on reset
Rx
Receive
SIM
System integration module
SOF
Start of frame
TAP
Test access port
TTL
Transistor-to-transistor logic
Tx
Transmit
UART
Universal asynchronous/synchronous receiver transmitter
Part II. System Integration Module (SIM)
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II-iv
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Chapter 6
SIM Overview
This chapter provides detailed operation information regarding the system integration
module (SIM). It describes the SIM programming model, bus arbitration, and
system-protection functions for the MCF5307.
6.1 Features
The SIM, shown in Figure 6-1, provides overall control of the bus and serves as the
interface between the ColdFire core processor complex and the internal peripheral devices.
BCLKO (to on-chip peripherals)
V3 COLDFIRE PROCESSOR COMPLEX
CLKIN
PLL
Xn
RSTI
PCLK
RSTO
DMA
SYSTEM INTEGRATION MODULE (SIM)
PLL Control
PLL
System Control
RSR
SWIVR
Base Address
Bus Master Park
Parallel Port
MBAR
MPARK
PAR
Software
Watchdog
SYPCR SWSR
DRAM Controller
Chip Select Module
DRAM Control
DCR
External
Bus Interface
8
8
8
CSARs CSCRs CSMRs
Interrupt Controller
I2C Module
10 ICRs
Two UARTs
IRQPAR
IPR
Addr/Cntrl Mask
DACR0/1
IMR
DMR0/1
AVR
8
DRAM Controller Outputs
Four
Channels
CS[7:0]
4
32-Bit Data Bus
32-Bit Address Bus
Two
GeneralPurpose
Timers
IRQ[1,3,5,7]
Control Signals
Figure 6-1. SIM Block Diagram
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The following is a list of the key SIM features:
•
•
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•
•
•
•
•
6-2
Module base address register (MBAR)
— Base address location of all internal peripherals and SIM resources
— Address space masking to internal peripherals and SIM resources
Phase-locked loop (PLL) clock control register (PLLCR) for CPU STOP instruction
— Control for turning off clocks to core and interrupt levels that turn clocks back on
Chapter 7, “Phase-Locked Loop (PLL).”
Interrupt controller
— Programmable interrupt level (1–7) for internal peripheral interrupts
— Programmable priority level (0–3) within each interrupt level
— Four external interrupts; one set to interrupt level 7; three others programmable
to two interrupt levels
See Chapter 9, “Interrupt Controller.”
Chip select module
— Eight independent, user-programmable chip-select signals (CS[7:0]) that can
interface with SRAM, PROM, EPROM, EEPROM, Flash, and peripherals
— Address masking for 64-Kbyte to 4-Gbyte memory block sizes
— Programmable wait states and port sizes
— External master access to chip selects
See Chapter 10, “Chip-Select Module.”
System protection and reset status
— Reset status indicating the cause of last reset
— Software watchdog timer with programmable secondary bus monitor
See Section 6.2.4, “Software Watchdog Timer.”
Pin assignment register (PAR) configures the parallel port. See Section 6.2.9, “Pin
Assignment Register (PAR).”
Bus arbitration
— Default bus master park register (MPARK) controls internal and external bus
arbitration and enables display of internal accesses on the external bus for
debugging
— Supports several arbitration algorithms
See Section 6.2.10, “Bus Arbitration Control.”
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Programming Model
6.2 Programming Model
The following sections describe the registers incorporated into the SIM.
6.2.1 SIM Register Memory Map
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Table 6-1 shows the memory map for the SIM registers. The internal registers in the SIM
are memory-mapped registers offset from the MBAR address pointer defined in
MBAR[BA]. This supervisor-level register is described in Section 6.2.2, “Module Base
Address Register (MBAR).” Because SIM registers depend on the base address defined in
MBAR[BA], MBAR must be programmed before SIM registers can be accessed.
NOTE:
Although external masters cannot access the MCF5307’s
on-chip memories or MBAR, they can access any of the SIM
memory map and peripheral registers, such as those belonging
to the interrupt controller, chip-select module, UARTs, timers,
DMA, and I2C.
Table 6-1. SIM Registers
MBAR
Offset
0x000
0x004
[31:24]
[23:16]
[15:8]
[7:0]
Reset status register
(RSR) [p. 6-5]
System protection
control register
(SYPCR) [p. 6-8]
Software watchdog
interrupt vector register
(SWIVR) [p. 6-9]
Software watchdog
service register (SWSR)
[p. 6-9]
Interrupt port
assignment register
(IRQPAR) [p. 9-7]
Reserved
Pin assignment register (PAR) [p. 6-10]
0x008
PLL control (PLLCR)
[p. 7-3]
Reserved
0x00C
Default bus master park
register (MPARK)
[p. 6-11]
Reserved
0x010–
0x03C
Reserved
Interrupt Controller Registers [p. 9-2]
0x040
Interrupt pending register (IPR) [p. 9-6]
0x044
Interrupt mask register (IMR) [p. 9-6]
0x048
Reserved
Autovector register
(AVR) [p. 9-5]
Interrupt Control Registers (ICRs) [p. 9-3]
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Table 6-1. SIM Registers (Continued)
MBAR
Offset
[31:24]
[23:16]
[15:8]
[7:0]
0x04C
Software watchdog
timer (ICR0) [p. 9-3]
Timer0 (ICR1) [p. 9-3]
Timer1 (ICR2) [p. 9-3]
I2C (ICR3) [p. 9-3]
0x050
UART0 (ICR4) [p. 9-3]
UART1 (ICR5) [p. 9-3]
DMA0 (ICR6) [p. 9-3]
DMA1 (ICR7) [p. 9-3]
0x054
DMA2 (ICR8) [p. 9-3]
DMA3 (ICR9) [p. 9-3]
Reserved
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6.2.2 Module Base Address Register (MBAR)
The supervisor-level MBAR, Figure 6-2, specifies the base address and allowable access
types for all internal peripherals. It is written with a MOVEC instruction using the CPU
address 0xC0F. (See the ColdFire Family Programmer’s Reference Manual.) MBAR can
be read or written through the debug module as a read/write register, as described in
Chapter 5, “Debug Support.” Only the debug module can read MBAR.
The valid bit, MBAR[V], is cleared at system reset to prevent incorrect references before
MBAR is written; other MBAR bits are uninitialized at reset. To access internal peripherals,
write MBAR with the appropriate base address (BA) and set MBAR[V] after system reset.
All internal peripheral registers occupy a single relocatable memory block along 4-Kbyte
boundaries. If MBAR[V] is set, MBAR[BA] is compared to the upper 20 bits of the full
32-bit internal address to determine if an internal peripheral is being accessed. MBAR
masks specific address spaces using the address space fields. Attempts to access a masked
address space generate an external bus access.
Addresses hitting overlapping memory spaces take the following priority:
1. MBAR
2. SRAM and caches
3. Chip select
NOTE:
The MBAR region must be mapped to non-cacheable space.
Attribute Mask Bits
31
Field
Reset
R/W
Address
12 11 10 9
BA
—
8
7
6
5
3
2
Undefined
W (supervisor only); R/W through debug module (only the debug module can read MBAR)
CPU + 0x0C0F
Figure 6-2. Module Base Address Register (MBAR)
6-4
4
1
0
WP — AM C/I SC SD UC UD V
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Table 6-2 describes MBAR fields.
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Table 6-2. MBAR Field Descriptions
Bits
Field
31–12
BA
11–9
—
8
WP
Description
Base address. Defines the base address for a 4-Kbyte address range.
Reserved, should be cleared.
Write protect. Mask bit for write cycles in the MBAR-mapped register address range.
0 Module address range is read/write.
1 Module address range is read only.
7
—
Reserved, should be cleared.
6
AM
Alternate master mask. When AM = 0 and an alternate master (external master or DMA) accesses
MBAR-mapped registers, MBAR[SC,SD,UC,UD] are ignored in address decoding. These fields
mask address space, placing the MBAR-mapped register in a specific address space or spaces.
5
C/I
Mask CPU space and interrupt acknowledge cycles.
0 Activates the corresponding MBAR-mapped register
1 Regular external bus access
4
SC
Setting masks supervisor code space in MBAR address range
3
SD
Setting masks supervisor data space in MBAR address range
2
UC
Setting masks user code space in MBAR address range
1
UD
0
V
Setting masks user data space in MBAR address range
Valid. Determines whether MBAR settings are valid.
0 MBAR contents are invalid.
1 MBAR contents are valid.
The following example shows how to set the MBAR to location 0x1000_0000 using the D0
register. Setting MBAR[V] validates the MBAR location. This example assumes all
accesses are valid:
move.1 #0x10000001,DO
movec DO,MBAR
6.2.3 Reset Status Register (RSR)
The reset status register (RSR), Figure 6-3, contains two status bits, HRST and SWTR.
Reset control logic sets one of the bits depending on whether the last reset was caused by
an external device asserting RSTI (HRST = 1) or by the software watchdog timer
(SWTR = 1). Only one RSR bit can be set at any time. If a reset occurs, reset control logic
sets only the bit that indicates the cause of reset.
7
Field HRST
Reset
R/W
Address
1/0
6
5
—
SWTR
4
—
0
0
1/0
0_0000
Read/Write
MBAR + 0x000
Figure 6-3. Reset Status Register (RSR)
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Table 6-3 describes RSR fields.
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Table 6-3. RSR Field Descriptions
Bits
Name
7
HRST
6
—
5
SWTR
4–0
—
Description
Hardware or system reset
1 An external device driving RSTI caused the last reset. Assertion of reset by an external
device causes the core processor to take a reset exception. All registers in internal
peripherals and the SIM are reset.
Reserved, should be cleared.
Software watchdog timer reset
1 The last reset was caused by the software watchdog timer. If SYPCR[SWRI] = 1 and the
software watchdog timer times out, a hardware reset occurs.
Reserved, should be cleared.
6.2.4 Software Watchdog Timer
The software watchdog timer prevents system lockup should the software become trapped
in loops with no controlled exit. The software watchdog timer can be enabled or disabled
through SYPCR[SWE]. If enabled, the watchdog timer requires the periodic execution of
a software watchdog servicing sequence. If this periodic servicing action does not occur,
the timer times out, resulting in a watchdog timer IRQ or hardware reset with RSTO driven
low, as programmed by SYPCR[SWRI].
If the timer times out and the software watchdog transfer acknowledge enable bit
(SYPCR[SWTA]) is set, a watchdog timer IRQ is asserted. Note that the software watchdog
timer IACK cycle cannot be autovectored.
If a software watchdog timer IACK cycle has not occurred after another timeout, SWT TA
is asserted in an attempt to terminate the bus cycle and allow the IACK cycle to proceed.
The setting of SYPCR[SWTAVAL] indicates that the watchdog timer TA was asserted.
Figure 6-4 shows termination of a locked bus.
6-6
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Programming Model
Code in the watchdog timer interrupt
handler polls SYPCR[SWTAVAL] to
determine if SWT TA was needed. If so,
execute code to identify bad address.
Code enables software watchdog timer interrupt and
SWTA functionality by writing SYPCR.
Problem:
1. Watchdog timer times out due to unterminated bus
NOTE: The watchdog timer IRQ should
be set to the highest level in the system.
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Software
watchdog
timer IRQ
Timeout
2. Watchdog timer interrupt cannot be serviced due to hung bus
cycle. Wait for another timeout before setting SYPCR[SWTA].
3. TA held until another
bus cycle starts
Software
watchdog
timer TA
Timeout
SYPCR[SWTAVAL] 1
1
SWTAVAL is set if watchdog timer TA is asserted.
Watchdog timer
IACK cycle
Figure 6-4. MCF5307 Embedded System Recovery from Unterminated Access
When the watchdog timer times out and SYPCR[SWRI] is programmed for a software
reset, an internal reset is asserted and RSR[SWTR] is set.
To prevent the watchdog timer from interrupting or resetting, the SWSR must be serviced
by performing the following sequence:
1. Write 0x55 to SWSR.
2. Write 0xAA to the SWSR.
Both writes must occur in order before the timeout, but any number of instructions or
SWSR accesses can be executed between the two writes. This order allows interrupts and
exceptions to occur, if necessary, between the two writes.
Caution should be exercised when changing SYPCR values after the software watchdog
timer has been enabled with the setting of SYPCR[SWE], because it is difficult to
determine the state of the watchdog timer while it is running. The countdown value is
constantly compared with the timeout period specified by SYPCR[SWP,SWT]. Therefore,
altering SWP and SWT improperly causes unpredictable processor behavior. The following
steps must be taken to change SWP or SWT:
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1.
2.
3.
4.
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Disable the software watchdog timer by clearing SYPCR[SWE].
Reset the counter by writing 0x55 and then 0xAA to SWSR.
Update SYPCR[SWT,SWP].
Reenable the watchdog timer by setting SYPCR[SWE]. This can be done in step 3.
6.2.5 System Protection Control Register (SYPCR)
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The SYPCR, Figure 6-5, controls the software watchdog timer, timeout periods, and
software watchdog timer transfer acknowledge. The SYPCR can be read at any time, but
can be written only if a software watchdog timer IRQ is not pending. At system reset, the
software watchdog timer is disabled.
Field
7
6
5
SWE
SWRI
SWP
4
3
SWT
Reset
2
1
0
SWTA
SWTAVAL
—
0000_0000
R/W
R/W
Address
MBAR + 0x01
Figure 6-5. System Protection Control Register (SYPCR)
Table 6-4 describes SYPCR fields.
Table 6-4. SYPCR Field Descriptions
Bits
Name
7
SWE
Software watchdog timer enable
0 Software watchdog timer disabled
1 Software watchdog timer enabled
Description
6
SWRI
Software watchdog reset/interrupt select
0 If a timeout occurs, the watchdog timer generates an interrupt to the core processor at the
level programmed into ICR0[IL].
1 The software watchdog timer causes soft reset to be asserted for all modules of the part
except for the PLL (reset mode selects, such as PP_RESET_SEL or chip-select settings,
should not change).
5
SWP
Software watchdog prescaler. This bit interacts with SYPCR[SWT].
0 Software watchdog timer clock not prescaled.
1 Software watchdog timer clock prescaled by 8192.
4–3
SWT
Software watchdog timing delay. SWT and SWP select the timeout period for the watchdog
timer. At system reset, the software watchdog timer is set to the minimum timeout period.
SWP = 0
00 29/system frequency
01 211/system frequency
10 213/system frequency
11 215/system frequency
SWP = 1
00 222/system frequency
01 224/system frequency
10 226/system frequency
11 228/system frequency
Note that if SWP and SWT are modified to select a new software timeout, the software service
sequence must be performed (0x55 followed by 0xAA written to the SWSR) before the new
timeout period takes effect.
6-8
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Table 6-4. SYPCR Field Descriptions (Continued)
Bits
Name
Description
2
SWTA
Software watchdog transfer acknowledge enable
0 SWTA transfer acknowledge disabled
1 SWTA asserts transfer acknowledge enabled. After one timeout period of the unacknowledged
assertion of the software watchdog timer interrupt, the software watchdog transfer
acknowledge asserts, which allows the watchdog timer to terminate a bus cycle and allow the
IACK to occur.
1
SWTAVAL Software watchdog transfer acknowledge valid
0 SWTA transfer acknowledge has not occurred.
1 SWTA transfer acknowledge has occurred. Write a 1 to clear this flag bit.
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6.2.6 Software Watchdog Interrupt Vector Register (SWIVR)
The SWIVR, shown in Figure 6-6, contains the 8-bit interrupt vector (SWIV) that the SIM
returns during an interrupt-acknowledge cycle in response to a software watchdog
timer-generated interrupt. SWIVR is set to the uninitialized vector 0x0F at system reset.
7
Field
0
SWIV
Reset
0000_1111
R/W
Supervisor write only
Address
MBAR + 0x002
Figure 6-6. Software Watchdog Interrupt Vector Register (SWIVR)
Note that the software watchdog interrupt cannot be autovectored.
6.2.7 Software Watchdog Service Register (SWSR)
The SWSR, shown in Figure 6-7, is where the software watchdog timer servicing sequence
should be written. To prevent a watchdog timer timeout, the software service sequence must
be performed (0x55 followed by 0xAA written to the SWSR). Both writes must be
performed in order before the timeout, but any number of instructions or accesses to the
SWSR can be executed between the two writes. If the timer has timed out, writing to SWSR
does not cancel the interrupt (that is, IPR[SWT] remains set). The interrupt is cancelled
(and SWT is cleared) automatically when the IACK cycle is run.
7
0
Field
SWSR
Reset
Undetermined
R/W
Address
Supervisor write only
MBAR + 0x003
Figure 6-7. Software Watchdog Service Register (SWSR)
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6.2.8 PLL Clock Control for CPU STOP Instruction
The SIM contains the PLL clock control register, which is described in detail in
Section 7.2.4, “PLL Control Register (PLLCR).” PLLCR[ENBSTOP,PLLIPL] are
significant to the operation of the SIM, and are described as follows:
•
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•
PLLCR[ENBSTOP] must be set for the ColdFire CPU STOP instruction to be
acknowledged. This bit is cleared at reset and must be set for the MCF5307 to enter
low-power modes. The CPU STOP instruction stops only clocks to the core
processor. All internal modules remain clocked and can generate interrupts to restart
the ColdFire core. For example, the on-chip timer can be used to interrupt the
processor after a given timer countdown.
PLLCR[PLLIPL] determines the minimum level at which an interrupt (decoded as
an interrupt priority level or IPL) must occur to awaken the PLL. The PLL then turns
clocks back on to the core processor and interrupt exception processing takes place.
Table 6-5 describes PLLIPL settings to be compared against the interrupt ranges that
awaken the core processor from a CPU STOP instruction.
Table 6-5. PLLIPL Settings
PLLIPL
Description
000
Any interrupts can wake core
001
Interrupts 2–7
010
Interrupts 3–7
011
Interrupts 4–7
100
Interrupts 5–7
101
Interrupts 6–7
110
Interrupt 7 only
111
No interrupts can wake core
6.2.9 Pin Assignment Register (PAR)
The pin assignment register (PAR), Figure 6-8, allows the selection of pin assignments.
15
14
13
12
11
10
9
8
7
6
Field PAR15 PAR14 PAR13 PAR12 PAR11 PAR10 PAR9 PAR8 PAR7 PAR6
4
3
1
0
PP8
PP7
PP4
PP3
PP2
PP1 PP0
PARn = 1 A31
A24
TIP DREQ0 DREQ1 TM2
TM1
TM0
TT1
A29
A28
A27
A26
A25
PP5
2
PAR2 PAR1 PAR0
PARn = 0 PP15 PP14 PP13 PP12 PP11 PP10 PP9
A30
PP6
5
PAR5 PAR4 PAR3
TT0
Reset Determined by driving D4/ADDR_CONFIG with a 1 or 0 when RSTI negates. The system is configured as PP[15:0] if
D4 is low; otherwise alternate pin functions selected by PAR = 1 are used.
R/W
Address
R/W
Address MBAR + 0x004
Figure 6-8. Pin Assignment Register (PAR)
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6.2.10 Bus Arbitration Control
This section describes the bus arbitration register and the four arbitration schemes.
6.2.10.1 Default Bus Master Park Register (MPARK)
The MPARK, shown in Figure 6-9, determines the default bus master arbitration between
internal transfers (core and DMA module) and between internal and external transfers to
internal resources. This arbitration is needed because external masters can access internal
registers within the MCF5307 peripherals.
7
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Field
6
PARK
5
4
3
2
IARBCTRL EARBCTRL SHOWDATA
Reset
0
—
BCR24BIT
0000_0000
R/W
R/W
Address
MBAR + 0x0C
Figure 6-9. Default Bus Master Register (MPARK)
Table 6-6 describes MPARK bits.
Table 6-6. MPARK Field Descriptions
Bits
Name
Description
7–6
PARK
5
IARBCTRL
4
EARBCTRL External bus arbitration control. Enables internal register memory space to external bus
arbitration. Internal registers are those accessed at offsets to the MBAR. These include the
SIM, DMA, chip selects, timers, UARTs, I2C, and parallel port registers. These registers do
not include the MBAR; only the core can access the MBAR.
0 Arbitration disabled
1 Arbitration enabled
The use of this field is described in detail in Section 6.2.10.1.2, “Arbitration between Internal
and External Masters for Accessing Internal Resources.”
Park. Indicates the arbitration priority of internal transfers among MCF5307 resources.
00 Round-robin between DMA and ColdFire core
01 Park on master ColdFire core
10 Park on master DMA module
11 Park on current master
Use of this field is described in detail in Section 6.2.10.1.1, “Arbitration for Internally
Generated Transfers (MPARK[PARK]).”
Internal bus arbitration control. Controls external device access to the MCF5307 internal bus.
0 Arbitration disabled (single-master system)
1 Arbitration enabled. IARBCTRL must be set if external masters are using internal
resources like the DRAM controller or chip selects.
Use of this bit depends on whether the system has single or multiple masters, as follows:
• In a single-master system, IARBCTRL should stay cleared, disabling internal arbitration
by external masters. In this scenario, MPARK[PARK] applies only to priority of internal
masters over one another. Note that the internal DMA (master 3) has priority over the
ColdFire core (master 2), if internal DMA bandwidth is at its maximum (BWC = 000).
• In multiple master systems that expect to use internal resources like the DRAM controller
or chip selects, internal arbitration should be enabled. The external master defaults to the
highest priority internal master anytime BG is negated.
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Table 6-6. MPARK Field Descriptions (Continued)
Bits
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3
Name
Description
SHOWDATA Enable internal register data bus to be driven on external bus. EARBCTRL must be set for
this function to work. Section 6.2.10.1.2, “Arbitration between Internal and External Masters
for Accessing Internal Resources,” describes the proper use of SHOWDATA.
0 Do not drive internal register data bus values to external bus.
1 Drive internal register data bus values to external bus.
2–1
—
0
BCR24BIT
Reserved, should be cleared.
Controls the BCR and address mapping for DMA. Allows the BCR to be used as a 24-bit
register. Chapter 12, “DMA Controller Module,” describes the BCRs.
0 DMA BCRs function as 16-bit counters.
1 DMA BCRs function as 24-bit counters.
6.2.10.1.1 Arbitration for Internally Generated Transfers (MPARK[PARK])
MPARK[PARK] prioritizes internal transfers, which can be initiated by the core and the
on-chip DMA module, which contains all four DMA channels. Priority among the four
DMA channels in the module is determined by the BWC bits in their respective DMA
control registers (see Chapter 12, “DMA Controller Module”).
The four arbitration schemes for internally generated transfers are described as follows:
•
Round-robin scheme (PARK = 00)—Figure 6-10 shows round-robin arbitration
between the core and DMA module. Bus mastership alternates between the core and
DMA module.
Internal Bus Mastership
(Alternates between Core and DMA Module)
DMA MODULE
CORE
5th
3rd
1st
4th
2nd
Channel 0
Channel 1
Channel 2
Channel 3
Figure 6-10. Round Robin Arbitration (PARK = 00)
The DMA module presents only the highest-priority DMA request, and bus
mastership alternates between the core and DMA channel as long as both are
requesting bus mastership. Section 12.5.4.1, “External Request and Acknowledge
Operation,” includes a timing diagram showing a lower-priority DMA transfer.
When the processor is initialized, the core has first priority. If DMA channels 0 and
1 (both set to BWC = 010) assert an internal bus request during a core-generated bus
transfer, DMA channel 0 would gain bus mastership next. However, if the core
requests the bus during this DMA transfer, bus mastership returns to the core rather
than being granted to DMA channel 1.
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•
Note that the internal DMA has higher priority than the core if the internal DMA has
its bandwidth BWC bits set to 000 (maximum bandwidth).
Park on master core priority (PARK = 01)—The core retains bus mastership as long
as it needs it. After it negates its internal bus request, the core does not have to
rearbitrate for the bus unless the DMA module has requested the bus when it is idle.
The DMA module can be granted bus mastership only when the core is not asserting
its bus request. See Figure 6-11.
Core BR negated
DMA module BR asserted
Core BR negated
DMA module BR negated
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Programming Model
DMA Module
Core
Core BR asserted
DMA module BR negated/asserted
Figure 6-11. Park on Master Core Priority (PARK = 01)
•
Park on master DMA priority (PARK = 10)—The DMA module retains bus
mastership as long as it needs it. After it negates its internal bus request, the DMA
module does not have to rearbitrate for the bus unless the core has requested the bus
when it is idle. The core can be granted bus mastership only when the DMA module
is not asserting its bus request. See Figure 6-12.
DMA module BR asserted
Core BR negated/asserted
Core
DMA BR negated
Core BR negated
DMA Module
Core BR asserted
DMA module BR negated
Figure 6-12. Park on DMA Module Priority (PARK = 10)
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•
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Park on current master priority (PARK = 11)—The current bus master retains
mastership as long as it needs the bus. The other device can become the bus master
only when the bus is idle. For example, if the core is bus master out of reset, it retains
mastership as long as it needs the bus. It loses mastership only when it negates its
bus request signal and the DMA asserts its internal bus request signal. At this point
the DMA module is the bus master, and retains bus mastership as long as it needs
the bus. See Figure 6-13.
DMA module BR asserted
Core BR negated
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Core BR negated
DMA module BR negated
Core
Core BR asserted
DMA module BR asserted
DMA module BR negated
Core BR negated
DMA Module
Core BR asserted
DMA module BR negated
DMA module BR asserted
Core BR asserted
Figure 6-13. Park on Current Master Priority (PARK = 01)
6.2.10.1.2 Arbitration between Internal and External Masters for
Accessing Internal Resources
If an external device is programmed to access internal MCF5307 resources
(EARBCTRL = 1), the external device can gain bus mastership only when BG is negated.
This means neither the core nor the DMA controller can access the external bus until the
external device asserts BG. After the external master finishes its bus transfer and asserts
BG, the core has priority on the next available bus cycle regardless of the value of PARK.
Thus if the core asserts its internal bus request on this first bus cycle, it executes a bus cycle
even if PARK indicates the DMA should have priority. Then, after the bus transfer, the
PARK scheme returns to programmed functioning and the DMA is given bus mastership.
NOTE:
In all arbitration modes, if BG is negated, the external master
interface has highest priority. In this case, the ColdFire core has
second-highest priority, until the internal bus grant is asserted.
•
6-14
In a single-master system, the setting of EARBCTRL does not affect arbitration
performance. Typically, BG is tied low and the MCF5307 always owns the external
bus and internal register transfers are already shown on the external bus. In a system
where MCF5307 is the only master, this bit may remain cleared.
If the system needs external visibility of the data bus values during internal register
transfers for system debugging, both EARBCTRL and SHOWDATA must be set.
Note that when an internal register transfer is driven externally, TA becomes an
output, which is asserted (normally an input) to prevent external devices and
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•
Programming Model
memories from responding to internal register transfers that go to the external bus.
The AS signal and all chip-select-related strobe signals are not asserted.
Do not immediately follow a cycle in which SHOWDATA is set with a cycle using
fast termination.
In multiple-master systems, disabling arbitration with EARBCTRL allows
performance improvement because internal register bus transfer cycles do not
interfere with the external bus.
Having internal transfers go external may affect performance in two ways:
— If the internal device does not control the bus immediately, the core stalls until it
wins arbitration of the external bus.
— If the core wins arbitration instantly, it may kick the external master off of the
external bus unnecessarily for a transfer that did not need the external bus. For
debug, where this performance penalty is not a concern, setting EARBCTRL and
SHOWDATA provides external visibility of the internal bus cycles.
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Chapter 7
Phase-Locked Loop (PLL)
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This chapter describes configuration and operation of the phase-locked loop (PLL) module.
It describes in detail the registers and signals that support the PLL implementation.
7.1 Overview
The basic features of the MCF5307 PLL implementation are as follows:
•
•
The PLL locks to the clock input (CLKIN) frequency. It provides a processor clock
(PCLK) that is twice the input clock frequency and a programmable system bus
clock output (BCLKO) that is 1/2, 1/3, or 1/4 the PCLK frequency.
A buffered processor status clock (PSTCLK) is equal to the PCLK frequency, as
indicated in Figure 7-1. This signal is made available for system development.
The PLL module has the following three modes of operation:
•
•
•
Reset mode—In reset mode, the core/bus frequency ratio and other configuration
information is sampled. At reset, the PLL asserts the reset out signal, RSTO.
Normal mode—During normal operations, the divide ratio is programmed at reset
and is clock-multiplied to provide a maximum frequency of 90 MHz
Reduced-power mode—In reduced-power mode, the high-speed processor core
clocks are turned off without losing the register contents so that the system can be
reenabled by an unmasked interrupt or reset.
Figure 7-1 shows the frequency relationships of PLL module clock signals.
z
RSTO
PCLK
PSTCLK
CLKIN
PLL
CLKIN X 4
Divide
by 2
Divide by 2,
3, or 4
BCLKO
FREQ[1:0]
RSTI
DIVIDE[1:0]
Figure 7-1. PLL Module Block Diagram
Chapter 7. Phase-Locked Loop (PLL)
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PLL Operation
7.1.1 PLL:PCLK Ratios
The specifications for the clocks in the PLL module are summarized in Table 0-1.
Table 0-1. PLL Clock Specifications
Symbol
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—
Description
Frequency
PLL lock time
2.2 mS with CLKIN running at 45 MHz
CLKIN
Input clock
16.67 MHz–45 MHz
PCLK
Internal processor clock 33.34 MHz–90 MHz (CLKIN x 2)
PSTCLK
Processor status clock
33.34 MHz–90 MHz (CLKIN x 2)
BCLKO
Output clock
16.67 MHz–45 MHz
BCLKO/PCLK ratio
1/2
11.11 MHz–30 MHz
1/3
8.24 MHz–22.5 MHz
1/4
7.2 PLL Operation
The following sections provide detailed information about the three PLL modes.
7.2.1 Reset/Initialization
The PLL receives RSTI as an input directly from the pin. Additionally, signals are
multiplexed with D[3:0]/FREQ[1:0]:DIVIDE[1:0] while RSTI is asserted. These signals
are sampled during reset and registered by the PLL on the negation of RSTI to provide
initialization information. FREQ[1:0] and DIVIDE[1:0] are used by the PLL to select the
CLKIN frequency range and set the CLKIN/PCLK ratio, respectively.
7.2.2 Normal Mode
PCLK is divided to create the system bus clock, BCLKO. At reset, the logic level of
DIVIDE[1:0]/D[1:0] determines the BCLKO divisor. The bus clock can be 1/2, 1/3, or 1/4
of the PCLK frequency.
7.2.3 Reduced-Power Mode
The PCLK can be turned off in a predictable manner to conserve system power. To allow
fast restart of the MCF5307 processor core, the PLL continues to operate at the frequency
configured at reset. PCLK is disabled using the CPU STOP instruction and resumes normal
operation on interrupt, as described in Section 7.2.4, “PLL Control Register (PLLCR).”
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PLL Port List
7.2.4 PLL Control Register (PLLCR)
The PLL control register (PLLCR), Figure 7-2, provides control over the PLL.
7
6
5
Field ENBSTOP
4
3
2
PLLIPL
Reset
1
0
—
0000_0000
R/W
R/W
Address
MBAR + 0x08
Figure 7-2. PLL Control Register (PLLCR)
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Table 7-1 describes PLLCR bits.
Table 7-1. PLLCR Field Descriptions
Bit
Name
Description
7
ENBSTOP
Enable CPU STOP instruction. Must be set for the ColdFire CPU STOP instruction to be
acknowledged. Cleared at reset and must be subsequently set for the processor to enter
low-power modes. Only clocks to the core are turned off because of the CPU STOP instruction.
Internal modules remain clocked and can generate interrupts to restart the ColdFire core.
0 Disable CPU STOP
1 Enable CPU STOP; STOP instruction turns off clocks to the ColdFire core.
6–4
PLLIPL
PLL interrupt priority level to wake up from CPU STOP. Determines the minimum level an
interrupt (decoded as an interrupt priority level) must be to waken the PLL. The PLL then turns
clocks back on to the core processor and interrupt exception processing occurs.
000 Any interrupts can wake core
001 Interrupts 2–7
010 Interrupts 3–7
011 Interrupts 4–7
100 Interrupts 5–7
101 Interrupts 6–7
110 Interrupt 7 only
111 No interrupts can wake core. Any reset, including a watchdog reset, can wake the core.
No PLL phase lock time is required.
3–0
—
Reserved, should be cleared.
7.3 PLL Port List
Table 7-2 describes PLL module inputs.
Table 7-2. PLL Module Input SIgnals
SIgnal
Description
CLKIN
Input clock to the PLL. Input frequency must not be changed during operation. Changes are
recognized only at reset.
RSTI
Active-low asynchronous input that, when asserted, indicates PLL is to enter reset mode. As long as
RSTI is asserted, the PLL is held in reset and does not begin to lock.
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Table 7-2. PLL Module Input SIgnals
SIgnal
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FREQ[1:0]
Description
Input bus indicating the CLKIN frequency range. FREQ[1:0] are multiplexed with D[3:2] and are
sampled while RSTI is asserted. FREQ[1:0] must be correctly set for proper operation. These signals
do not affect CLKIN frequency but are required to set up the analog PLL to handle the input clock
frequency.
00 16.6–27.999 MHz
01 28–38.999 MHz
10 39–45 MHz
11 Not used
DIVIDE[1:0] The MCF5307 samples clock ratio encodings on the lower data bits of the bus to determine the
CLKIN-to-processor clock ratio. D[1:0]/DIVIDE[1:0] support the divide-ratio combinations.
00 1/4
01 Not used
10 1/2
11 1/3
Table 7-3 describes PLL module outputs.
Table 7-3. PLL Module Output Signals
Output
Description
BCLKO
This bus clock output provides a divided version of the processor clock frequency, determined by
DIVIDE[1:0].
PSTCLK
Provides a buffered processor status clock at 2X the CLKIN frequency. PSTCLK is a delayed version of
PCLK. See Section 7.4.1, “PCLK, PSTCLK, and BCLKO,” and Figure 7-1.
RSTO
This output provides an external reset for peripheral devices.
7.4 Timing Relationships
The MCF5307 uses CLKIN and BCLKO, which is generated by the PLL and may be used
as the bus timing reference for external devices. The MCF5307 BCLKO frequency can be
1/2, 1/3, or 1/4 the processor clock. In this document, bus timings are referenced from
BCLKO. Furthermore, depending on the user configuration, the BCLKO-to-processor
clock ratio may differ from the CLKIN-to-processor clock ratio.
7.4.1 PCLK, PSTCLK, and BCLKO
Figure 7-3 shows the frequency relationships between PCLK, PSTCLK,CLKIN, and the
three possible versions of BCLKO. This figure does not show the skew between CLKIN
and PCLK, PSTCLK, and BCLKO. PSTCLK is equal to frequency of PCLK. Similarly, the
skew between PCLK and BCLKO is unspecified.
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Timing Relationships
CLKIN
PCLK
PSTCLK
BCLKO (/2)
BCLKO (/3)
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BCLKO (/4)
NOTE:
The clock signals are shown with edges aligned to show frequency relationships only.
Actual signal edges have some skew between them.
Figure 7-3. CLKIN, PCLK, PSTCLK, and BCLKO Timing
7.4.2 RSTI Timing
Figure 7-4 shows PLL timing during reset. As shown, RSTI must be asserted for at least 80
CLKIN cycles to give the MCF5307 time to begin its initialization sequence. At this time,
the configuration pins should be asserted (D[3:2] for FREQ[1:0] and D[1:0] for
DIVIDE[1:0]), meeting the minimum setup and hold times to RSTI given in Chapter 20,
“Electrical Specifications.”
On the rising edge of BCLKO before the rising edge of RSTI, the data on D[7:0] is latched
and the PLL begins ramping to its final operating frequency. During this ramp and lock
time, BCLKO and PSTCLK are held low. The PLL locks in about 2.2 mS with a 45-MHz
CLKIN, at which time BCLKOand PSTCLK begin normal operation in the specified mode.
The PLL requires 100,000 CLKIN cycles to guarantee PLL lock. To allow for reset of
external peripherals requiring a clock source, RSTO remains asserted for a number of
BCLKO cycles, as shown in Figure 7-4.
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PLL Power Supply Filter Circuit
>80 CLKIN
100K CLKIN
Cycle Lock Time
CLKIN
30 BCLKO
BCLKO
(1/2 MODE)
20 BCLKO
BCLKO
(1/3 MODE)
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15 BCLKO
BCLKO
(1/4 MODE)
PSTCLK
RSTI
D[7:0]
D[7:0] latched
RSTO
Figure 7-4. Reset and Initialization Timing
7.5 PLL Power Supply Filter Circuit
To ensure PLL stability, the power supply to the PLL power pin should be filtered using a
circuit similar to the one in Figure 7-5. The circuit should be placed as close as possible to
the PLL power pin to ensure maximum noise filtering.
10 Ω
Vdd
PLL power pin
10 µF
0.1 µF
Figure 7-5. PLL Power Supply Filter Circuit
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Chapter 8
I2C Module
This chapter describes the MCF5307 I2C module, including I2C protocol, clock
synchronization, and the registers in the I2C programing model. It also provides extensive
programming examples.
8.1 Overview
I2C is a two-wire, bidirectional serial bus that provides a simple, efficient method of data
exchange, minimizing the interconnection between devices. This bus is suitable for
applications requiring occasional communications over a short distance between many
devices. The flexible I2C allows additional devices to be connected to the bus for expansion
and system development.
The I2C system is a true multiple-master bus including arbitration and collision detection
that prevents data corruption if multiple devices attempt to control the bus simultaneously.
This feature supports complex applications with multiprocessor control and can be used for
rapid testing and alignment of end products through external connections to an
assembly-line computer.
8.2 Interface Features
The I2C module has the following key features:
•
•
•
•
•
•
•
•
•
•
Compatibility with I2C bus standard
Support for 3.3-V tolerant devices
Multiple-master operation
Software-programmable for one of 64 different serial clock frequencies
Software-selectable acknowledge bit
Interrupt-driven, byte-by-byte data transfer
Arbitration-lost interrupt with automatic mode switching from master to slave
Calling address identification interrupt
Start and stop signal generation/detection
Repeated START signal generation
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Interface Features
•
•
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Acknowledge bit generation/detection
Bus-busy detection
Figure 8-1 is a block diagram of the I2C module.
Internal Bus
IRQ
Address
Data
Address Decode
Data MUX
I2C Data
I/O Register
(I2DR)
I2C Address
Register
(IADR)
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Registers and ColdFire Interface
I2C Frequency
Divider Register
(IFDR)
I2C Control
Register
(I2CR)
I2C Status
Register
(I2SR)
Clock
Control
Start, Stop,
and
Arbitration
Control
Input
Sync
In/Out
Data
Shift
Register
Address
Compare
SCL
SDA
Figure 8-1. I2C Module Block Diagram
Figure 8-1 shows the relationships of the I2C registers, listed below:
• I2C address register (IADR)
•
I2C frequency divider register (IFDR)
•
I2C control register (I2CR)
•
I2C status register (I2SR)
•
I2C data I/O register (I2DR)
These registers are described in Section 8.5, “Programming Model.”
8-2
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I C System Configuration
8.3 I2C System Configuration
The I2C module uses a serial data line (SDA) and a serial clock line (SCL) for data transfer.
For I2C compliance, all devices connected to these two signals must have open drain or
open collector outputs. (There is no such requirement for inputs.) The logic AND function
is exercised on both lines with external pull-up resistors.
Out of reset, the I2C default is as slave receiver. Thus, when not programmed to be a master
or responding to a slave transmit address, the I2C module should return to the default slave
receiver state. See Section 8.6.1, “Initialization Sequence,” for exceptions.
Freescale Semiconductor, Inc...
NOTE:
I2
The C module is designed to be compatible with the Philips
I2C bus protocol. For information on system configuration,
protocol, and restrictions, see The I2C Bus Specification,
Version 2.1.
8.4 I2C Protocol
Normally, a standard communication is composed of the following parts:
1. START signal—When no other device is bus master (both SCL and SDA lines are
at logic high), a device can initiate communication by sending a START signal (see
A in Figure 8-2). A START signal is defined as a high-to-low transition of SDA
while SCL is high. This signal denotes the beginning of a data transfer (each data
transfer can be several bytes long) and awakens all slaves.
msb
SCL
1
SDA
A
lsb
2
3
4
5
6
7
8
msb
9
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
START
Signal
Calling Address
B
R/W ACK
Bit
C
D
1
XXX
lsb
2
3
D7 D6 D5
E
4
5
6
7
8
9
D4 D3 D2 D1 D0
Data Byte
No STOP
ACK Signal
Bit
F
Figure 8-2. I2C Standard Communication Protocol
2. Slave address transmission—The master sends the slave address in the first byte
after the START signal (B). After the seven-bit calling address, it sends the R/W bit
(C), which tells the slave data transfer direction.
Each slave must have a unique address. An I2C master must not transmit an address
that is the same as its slave address; it cannot be master and slave at the same time.
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I2C Protocol
The slave whose address matches that sent by the master pulls SDA low at the ninth
clock (D) to return an acknowledge bit.
3. Data transfer—When successful slave addressing is achieved, the data transfer can
proceed (E) on a byte-by-byte basis in the direction specified by the R/W bit sent by
the calling master.
Data can be changed only while SCL is low and must be held stable while SCL is
high, as Figure 8-2 shows. SCL is pulsed once for each data bit, with the msb being
sent first. The receiving device must acknowledge each byte by pulling SDA low at
the ninth clock; therefore, a data byte transfer takes nine clock pulses.
If it does not acknowledge the master, the slave receiver must leave SDA high. The
master can then generate a STOP signal to abort the data transfer or generate a
START signal (repeated start, shown in Figure 8-3) to start a new calling sequence.
If the master receiver does not acknowledge the slave transmitter after a byte
transmission, it means end-of-data to the slave. The slave releases SDA for the
master to generate a STOP or START signal.
4. STOP signal—The master can terminate communication by generating a STOP
signal to free the bus. A STOP signal is defined as a low-to-high transition of SDA
while SCL is at logical high (F). Note that a master can generate a STOP even if the
slave has made an acknowledgment, at which point the slave must release the bus.
Instead of signalling a STOP, the master can repeat the START signal, followed by a calling
command, (A in Figure 8-3). A repeated START occurs when a START signal is generated
without first generating a STOP signal to end the communication.
msb
SCL
SDA
1
lsb
2
3
4
5
6
7
8
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
START
Signal
Calling Address
lsb
msb
9
1
XX
2
3
4
5
6
7
8
9
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
R/W ACK Repeated
Bit
START
Signal A
New Calling Address
Stop
R/W No
ACK
Bit
STOP
Signal
Figure 8-3. Repeated START
The master uses a repeated START to communicate with another slave or with the same
slave in a different mode (transmit/receive mode) without releasing the bus.
8.4.1 Arbitration Procedure
If multiple devices simultaneously request the bus, the bus clock is determined by a
synchronization procedure in which the low period equals the longest clock-low period
among the devices and the high period equals the shortest. A data arbitration procedure
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I2C Protocol
determines the relative priority of competing devices. A device loses arbitration if it sends
logic high while another sends logic low; it immediately switches to slave-receive mode
and stops driving SDA. In this case, the transition from master to slave mode does not
generate a STOP condition. Meanwhile, hardware sets I2SR[IAL] to indicate loss of
arbitration.
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8.4.2 Clock Synchronization
Because wire-AND logic is used, a high-to-low transition on SCL affects devices
connected to the bus. Devices start counting their low period when the master drives SCL
low. When a device clock goes low, it holds SCL low until the clock high state is reached.
However, the low-to-high change in this device clock may not change the state of SCL if
another device clock is still in its low period. Therefore, the device with the longest low
period holds the synchronized clock SCL low. Devices with shorter low periods enter a high
wait state during this time (See Figure 8-4). When all devices involved have counted off
their low period, the synchronized clock SCL is released and pulled high. There is then no
difference between device clocks and the state of SCL, so all of the devices start counting
their high periods. The first device to complete its high period pulls SCL low again.
Wait
Start counting high period
SCL1
SCL2
SCL
Internal Counter Reset
Figure 8-4. Synchronized Clock SCL
8.4.3 Handshaking
The clock synchronization mechanism can be used as a handshake in data transfers. Slave
devices can hold SCL low after completing one byte transfer (9 bits). In such a case, the
clock mechanism halts the bus clock and forces the master clock into wait states until the
slave releases SCL.
8.4.4 Clock Stretching
Slaves can use the clock synchronization mechanism to slow down the transfer bit rate.
After the master has driven SCL low, the slave can drive SCL low for the required period
and then release it. If the slave SCL low period is longer than the master SCL low period,
the resulting SCL bus signal low period is stretched.
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Programming Model
8.5 Programming Model
Table 8-1 lists the configuration registers used in the I2C interface.
Table 8-1. I2C Interface Memory Map
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MBAR
Offset
[31:24]
[23:16]
[15:8]
0x280
I2C address register (IADR) [p. 8-6]
0x284
I2C frequency divider register (IFDR) [p. 8-7]
Reserved
0x288
I2C control register (I2CR) [p. 8-8]
Reserved
0x28C
I2C status register (I2SR) [p. 8-9]
Reserved
0x290
I2C data I/O register (I2DR) [p. 8-10]
Reserved
[7:0]
Reserved
NOTE:
External masters cannot access the MCF5307’s on-chip
memories or MBAR, but can access any I2C module register.
8.5.1 I2C Address Register (IADR)
The IADR holds the address the I2C responds to when addressed as a slave. Note that it is
not the address sent on the bus during the address transfer.
7
6
5
Field
4
3
2
1
ADR
Reset
0
—
0000_0000
R/W
Read/Write
Address
MBAR + 0x280
Figure 8-5. I2C Address Register (IADR)
Table 8-2 describes IADR fields.
Table 8-2. I2C Address Register Field Descriptions
Bits
Name
Description
7–1
ADR
Slave address. Contains the specific slave address to be used by the I2C module. Slave mode is
the default I2C mode for an address match on the bus.
0
—
Reserved, should be cleared.
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8.5.2 I2C Frequency Divider Register (IFDR)
The IFDR, Figure 8-6, provides a programmable prescaler to configure the clock for
bit-rate selection.
7
Field
6
5
4
3
—
2
1
0
IC
Reset
0000_0000
R/W
Read/Write
Address
MBAR + 0x284
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Figure 8-6. I2C Frequency Divider Register (IFDR)
Table 8-3 describes IFDR[IC].
Table 8-3. IFDR Field Descriptions
Bits
Name
Description
7–6
—
Reserved, should be cleared.
5–0
IC
I2C clock rate. Prescales the clock for bit-rate selection. Due to potentially slow SCL and SDA rise and
fall times, bus signals are sampled at the prescaler frequency. The serial bit clock frequency is equal to
BCLK0 divided by the divider shown below. Note that IC can be changed anywhere in a program.
IC
Divider
IC
Divider
IC
Divider
IC
Divider
0x00
28
0x10
288
0x20
20
0x30
160
0x01
30
0x11
320
0x21
22
0x31
192
0x02
34
0x12
384
0x22
24
0x32
224
0x03
40
0x13
480
0x23
26
0x33
256
0x04
44
0x14
576
0x24
28
0x34
320
0x05
48
0x15
640
0x25
32
0x35
384
0x06
56
0x16
768
0x26
36
0x36
448
0x07
68
0x17
960
0x27
40
0x37
512
0x08
80
0x18
1152
0x28
48
0x38
640
0x09
88
0x19
1280
0x29
56
0x39
768
0x0A
104
0x1A
1536
0x2A
64
0x3A
896
0x0B
128
0x1B
1920
0x2B
72
0x3B
1024
0x0C
144
0x1C
2304
0x2C
80
0x3C
1280
0x0D
160
0x1D
2560
0x2D
96
0x3D
1536
0x0E
192
0x1E
3072
0x2E
112
0x3E
1792
0x0F
240
0x1F
3840
0x2F
128
0x3F
2048
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8.5.3 I2C Control Register (I2CR)
The I2CR is used to enable the I2C module and the I2C interrupt. It also contains bits that
govern operation as a slave or a master.
Field
7
6
5
4
3
2
IEN
IIEN
MSTA
MTX
TXAK
RSTA
Reset
1
0
—
0000_0000
R/W
Read/Write
Address
MBAR + 0x288
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Figure 8-7. I2C Control Register (I2CR)
Table 8-4 describes I2CR fields.
Table 8-4. I2CR Field Descriptions
Bits
Name
Description
7
IEN
enable. Controls the software reset of the entire I2C module. If the module is enabled in the
middle of a byte transfer, slave mode ignores the current bus transfer and starts operating when the
next start condition is detected. Master mode is not aware that the bus is busy; so initiating a start
cycle may corrupt the current bus cycle, ultimately causing either the current master or the I2C
module to lose arbitration, after which bus operation returns to normal.
0 The module is disabled, but registers can still be accessed.
1 The I2C module is enabled. This bit must be set before any other I2CR bits have any effect.
6
IIEN
I2C interrupt enable.
0 I2C module interrupts are disabled, but currently pending interrupt condition are not cleared.
1 I2C module interrupts are enabled. An I2C interrupt occurs if I2SR[IIF] is also set.
5
MSTA
Master/slave mode select bit. If the master loses arbitration, MSTA is cleared without generating a
STOP signal.
0 Slave mode. Changing MSTA from 1 to 0 generates a STOP and selects slave mode.
1 Master mode. Changing MSTA from 0 to 1 signals a START on the bus and selects master mode.
4
MTX
Transmit/receive mode select bit. Selects the direction of master and slave transfers.
0 Receive
1 Transmit. When a slave is addressed, software should set MTX according to I2SR[SRW]. In
master mode, MTX should be set according to the type of transfer required. Therefore, for address
cycles, MTX is always 1.
3
TXAK
Transmit acknowledge enable. Specifies the value driven onto SDA during acknowledge cycles for
both master and slave receivers. Note that writing TXAK applies only when the I2C bus is a receiver.
0 An acknowledge signal is sent to the bus at the ninth clock bit after receiving one byte of data.
1 No acknowledge signal response is sent (that is, acknowledge bit = 1).
2
RSTA
Repeat start. Always read as 0. Attempting a repeat start without bus mastership causes loss of
arbitration.
0 No repeat start
1 Generates a repeated START condition.
1–0
—
Reserved, should be cleared.
8-8
I2C
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8.5.4 I2C Status Register (I2SR)
This I2SR contains bits that indicate transaction direction and status.
Field
7
6
5
4
3
2
1
0
ICF
IAAS
IBB
IAL
—
SRW
IIF
RXAK
R/W
R
Reset
R/W
1000_0001
R
R
R/W
Address
MBAR + 0x28C
Figure 8-8.
I2CR
Status Register (I2SR)
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Table 8-5 describes I2SR fields.
Table 8-5. I2SR Field Descriptions
Bits
Name
Description
7
ICF
Data transferring bit. While one byte of data is transferred, ICF is cleared.
0 Transfer in progress
1 Transfer complete. Set by the falling edge of the ninth clock of a byte transfer.
6
IAAS
I2C addressed as a slave bit. The CPU is interrupted if I2CR[IIEN] is set. Next, the CPU must check
SRW and set its TX/RX mode accordingly. Writing to I2CR clears this bit.
0 Not addressed.
1 Addressed as a slave. Set when its own address (IADR) matches the calling address.
5
IBB
I2C bus busy bit. Indicates the status of the bus.
0 Bus is idle. If a STOP signal is detected, IBB is cleared.
1 Bus is busy. When START is detected, IBB is set.
4
IAL
Arbitration lost. Set by hardware in the following circumstances. (IAL must be cleared by software by
writing zero to it.)
• SDA sampled low when the master drives high during an address or data-transmit cycle.
• SDA sampled low when the master drives high during the acknowledge bit of a data-receive
cycle.
• A start cycle is attempted when the bus is busy.
• A repeated start cycle is requested in slave mode.
• A stop condition is detected when the master did not request it.
3
—
Reserved, should be cleared.
2
SRW
Slave read/write. When IAAS is set, SRW indicates the value of the R/W command bit of the calling
address sent from the master. SRW is valid only when a complete transfer has occurred, no other
transfers have been initiated, and the I2C module is a slave and has an address match.
0 Slave receive, master writing to slave.
1 Slave transmit, master reading from slave.
1
IIF
I2C interrupt. Must be cleared by software by writing a zero to it in the interrupt routine.
0 No I2C interrupt pending
1 An interrupt is pending, which causes a processor interrupt request (if IIEN = 1). Set when one of
the following occurs:
• Complete one byte transfer (set at the falling edge of the ninth clock)
• Reception of a calling address that matches its own specific address in slave-receive mode
• Arbitration lost
0
RXAK
Received acknowledge. The value of SDA during the acknowledge bit of a bus cycle.
0 An acknowledge signal was received after the completion of 8-bit data transmission on the bus
1 No acknowledge signal was detected at the ninth clock.
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I2C Programming Examples
8.5.5 I2C Data I/O Register (I2DR)
In master-receive mode, reading the I2DR, Figure 8-9, allows a read to occur and initiates
next byte data receiving. In slave mode, the same function is available after it is addressed.
7
6
5
4
3
Field
D
Reset
0000_0000
R/W
2
1
0
Read/Write
Address
MBAR + 0x290
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Figure 8-9. I2C Data I/O Register (I2DR)
8.6 I2C Programming Examples
The following examples show programming for initialization, signalling START,
post-transfer software response, signalling STOP, and generating a repeated START.
8.6.1 Initialization Sequence
Before the interface can transfer serial data, registers must be initialized, as follows:
1. Set IFDR[IC] to obtain SCL frequency from the system bus clock. See
Section 8.5.2, “I2C Frequency Divider Register (IFDR).”
2. Update the IADR to define its slave address.
3. Set I2CR[IEN] to enable the I2C bus interface system.
4. Modify the I2CR to select master/slave mode, transmit/receive mode, and
interrupt-enable or not.
NOTE:
If IBSR[IBB] when the I2C bus module is enabled, execute the
following code sequence before proceeding with normal
initialization code. This issues a STOP command to the slave
device, placing it in idle state as if it were just power-cycled on.
I2CR = 0x0
I2CR = 0xA
dummy read of I2DR
IBSR = 0x0
I2CR = 0x0
8.6.2 Generation of START
After completion of the initialization procedure, serial data can be transmitted by selecting
the master transmitter mode. On a multiple-master bus system, IBSR[IBB] must be tested
to determine whether the serial bus is free. If the bus is free (IBB = 0), the START signal
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I C Programming Examples
and the first byte (the slave address) can be sent. The data written to the data register
comprises the address of the desired slave and the lsb indicates the transfer direction.
The free time between a STOP and the next START condition is built into the hardware that
generates the START cycle. Depending on the relative frequencies of the system clock and
the SCL period, it may be necessary to wait until the I2C is busy after writing the calling
address to the I2DR before proceeding with the following instructions.
The following example signals START and transmits the first byte of data (slave address):
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CHFLAG
MOVE.B I2SR,-(A0);Check I2SR[MBB]
BTST.B #5, (A0)+
BNE.S CHFLAG;If I2SR[MBB] = 1, wait until it is clear
TXSTART MOVE.B I2CR,-(A0);Set transmit mode
BSET.B #4,(A0)
MOVE.B (A0)+, I2CR
MOVE.B I2CR, -(A0);Set master mode
BSET.B #5, (A0);Generate START condition
MOVE.B (A0)+, I2CR
MOVE.B CALLING,-(A0);Transmit the calling address, D0=R/W
MOVE.B (A0)+, I2DR
IFREE
MOVE.B I2SR,-(A0);Check I2SR[MBB]
;If it is clear, wait until it is set.
BTST.B #5, (A0)+;
BEQ.S IFREE;
8.6.3 Post-Transfer Software Response
Sending or receiving a byte sets the I2SR[ICF], which indicates one byte communication
is finished. I2SR[IIF] is also set. An interrupt is generated if the interrupt function is
enabled during initialization by setting I2CR[IIEN]. Software must first clear IIF in the
interrupt routine. ICF is cleared either by reading from I2DR in receive mode or by writing
to I2DR in transmit mode.
Software can service the I2C I/O in the main program by monitoring IIF if the interrupt
function is disabled. Polling should monitor IIF rather than ICF because that operation is
different when arbitration is lost.
When an interrupt occurs at the end of the address cycle, the master is always in transmit
mode; that is, the address is sent. If master receive mode is required (I2DR[R/W],
I2CR[MTX] should be toggled.
During slave-mode address cycles (I2SR[IAAS] = 1), I2SR[SRW] is read to determine the
direction of the next transfer. MTX is programmed accordingly. For slave-mode data cycles
(IAAS = 0), SRW is invalid. MTX should be read to determine the current transfer
direction.
The following is an example of a software response by a master transmitter in the interrupt
routine (see Figure 8-10).
I2SR
LEA.L I2SR,-(A7);Load effective address
BCLR.B #1,(A7)+;Clear the IIF flag
MOVE.B I2CR,-(A7);Push the address on stack,
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I2C Programming Examples
BTST.B #5,(A7)+;check the MSTA flag
BEQ.S SLAVE;Branch if slave mode
MOVE.B I2CR,-(A7);Push the address on stack
BTST.B #4,(A7)+;check the mode flag
BEQ.S RECEIVE;Branch if in receive mode
MOVE.B I2SR,-(A7);Push the address on stack,
BTST.B #0,(A7)+;check ACK from receiver
BNE.B END;If no ACK, end of transmission
TRANSMITMOVE.B DATABUF,-(A7);Stack data byte
MOVE.B (A7)+, I2DR;Transmit next byte of data
8.6.4 Generation of STOP
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A data transfer ends when the master signals a STOP, which can occur after all data is sent,
as in the following example.
MASTX
END
MOVE.B I2SR, -(A7);If no ACK, branch to end
BTST.B #0,(A7)+
BNE.B END
MOVE.B TXCNT,D0;Get value from the transmitting counter
BEQ.S END;If no more data, branch to end
MOVE.B DATABUF,-(A7);Transmit next byte of data
MOVE.B (A7)+,I2DR
MOVE.B TXCNT,D0;Decrease the TXCNT
SUBQ.L #1,D0
MOVE.B D0,TXCNT
BRA.S EMASTX;Exit
LEA.L I2CR,-(A7);Generate a STOP condition
BCLR.B #5,(A7)+
EMASTX RTE;Return from interrupt
For a master receiver to terminate a data transfer, it must inform the slave transmitter by not
acknowledging the last data byte. This is done by setting I2CR[TXAK] before reading the
next-to-last byte. Before the last byte is read, a STOP signal must be generated, as in the
following example.
MASR
MOVE.B RXCNT,D0;Decrease RXCNT
SUBQ.L #1,D0
MOVE.B D0,RXCNT
BEQ.S ENMASR;Last byte to be read
MOVE.B RXCNT,D1;Check second-to-last byte to be read
EXTB.L D1
SUBI.L #1,D1;
BNE.S NXMAR;Not last one or second last
LAMAR BSET.B #3,I2CR;Disable ACK
BRA NXMAR
ENMASR
NXMAR
BCLR.B #5,I2CR;Last one, generate STOP signal
MOVE.B I2DR,RXBUF;Read data and store RTE
8.6.5 Generation of Repeated START
After the data transfer, if the master still wants the bus, it can signal another START
followed by another slave address without signalling a STOP, as in the following example.
RESTART MOVE.B
BSET.B
MOVE.B
MOVE.B
MOVE.B
MOVE.B
8-12
I2CR,-(A7);Repeat START (RESTART)
#2, (A7)
(A7)+, I2CR
CALLING,-(A7);Transmit the calling address, D0=R/WCALLING,-(A7);
(A7)+, I2DR
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I C Programming Examples
8.6.6 Slave Mode
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In the slave interrupt service routine, the module addressed as slave bit (IAAS) should be
tested to check if a calling of its own address has just been received. If IAAS is set, software
should set the transmit/receive mode select bit (I2CR[MTX]) according to the I2SR[SRW].
Writing to the I2CR clears the IAAS automatically. The only time IAAS is read as set is
from the interrupt at the end of the address cycle where an address match occurred;
interrupts resulting from subsequent data transfers will have IAAS cleared. A data transfer
can now be initiated by writing information to I2DR for slave transmits, or read from I2DR
in slave-receive mode. A dummy read of I2DR in slave/receive mode releases SCL,
allowing the master to send data.
In the slave transmitter routine, I2SR[RXAK] must be tested before sending the next byte
of data. Setting RXAK means an end-of-data signal from the master receiver, after which
software must switch it from transmitter to receiver mode. Reading I2DR then releases SCL
so that the master can generate a STOP signal.
8.6.7 Arbitration Lost
If several devices try to engage the bus at the same time, one becomes master. Hardware
immediately switches devices that lose arbitration to slave receive mode. Data output to
SDA stops, but SCL is still generated until the end of the byte during which arbitration is
lost. An interrupt occurs at the falling edge of the ninth clock of this transfer with
I2SR[IAL] = 1 and I2CR[MSTA] = 0.
If a device that is not a master tries to transmit or do a START, hardware inhibits the
transmission, clears MSTA without signalling a STOP, generates an interrupt to the CPU,
and sets IAL to indicate a failed attempt to engage the bus. When considering these cases,
the slave service routine should first test IAL and software should clear it if it is set.
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I2C Programming Examples
Clear
IIF
Y
TX
TX/Rx
?
Master
Mode?
N
Y
RX
Arbitration
Lost?
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N
Last Byte
Transmitted
?
N
RXAK= 0
?
Clear IAL
Y
Last
Byte to be
Read ?
N
Y
Y
N
End of
ADDR Cycle
(Master RX)
?
N
Write Next
Byte to I2DR
N
Y
Y
(Read)Y
N Data
Cycle
SRW=1
?
Generate
STOP Signal
Switch to
Rx Mode
Generate
STOP Signal
Tx/Rx
?
N (WRITE)
N
Y
Set TX
Mode
Write Data
to I2DR
Dummy Read
from I2DR
IAAS=1
?
Address Y
Cycle
2nd Last
Byte to be
Read?
Set TXAK =1
Y
IAAS=1
?
Read Data
from I2DR
And Store
TX
ACK from
Receiver
?
N
Read Data
from I2DR
and Store
Tx Next
Byte
Set RX
Mode
Switch to
Rx Mode
Dummy Read
from I2DR
Dummy Read
from I2DR
RTE
Figure 8-10. Flow-Chart of Typical I2C Interrupt Routine
8-14
RX
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Chapter 9
Interrupt Controller
This chapter describes the operation of the interrupt controller portion of the system
integration module (SIM). It includes descriptions of the registers in the interrupt controller
memory map and the interrupt priority scheme.
9.1 Overview
The SIM provides a centralized interrupt controller for all MCF5307 interrupt sources,
which consist of the following:
•
•
•
External interrupts
Software watchdog timer
Timer modules
•
•
•
I2C module
UART modules
DMA module
Figure 9-1 is a block diagram of the interrupt controller.
System Integration Module (SIM)
DMA
Four
Channels
Interrupt Controller
12 ICRs
IRQPAR
Software
Watchdog
I2C Module
IPR
IMR
AVR
4
IRQ[1,3,5,7]
Two UARTs
Two
GeneralPurpose
Timers
Figure 9-1. Interrupt Controller Block Diagram
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Interrupt Controller Registers
The SIM provides the following registers for managing interrupts:
•
•
•
•
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•
Each potential interrupt source is assigned one of the 10 interrupt control registers
(ICR0–ICR9), which are used to prioritize the interrupt sources.
The interrupt mask register (IMR) provides bits for masking individual interrupt
sources.
The interrupt pending register (IPR) provides bits for indicating when an interrupt
request is being made (regardless of whether it is masked in the IMR).
The autovector register (AVEC) controls whether the SIM supplies an autovector or
executes an external interrupt acknowledge cycle for each IRQ.
The interrupt port assignment register (IRQPAR) provides the level assignment of
the primary external interrupt pins—IRQ5, IRQ3, and IRQ1.
9.2 Interrupt Controller Registers
The interrupt controller register portion of the SIM memory map is shown in Table 9-2.
Table 9-1. Interrupt Controller Registers
MBAR
Offset
[31:24]
[23:16]
[15:8]
0x040
Interrupt pending register (IPR) [p. 9-6]
0x044
Interrupt mask register (IMR) [p. 9-6]
0x048
Reserved
[7:0]
Autovector register
(AVR) [p. 9-5]
Interrupt Control Registers (ICRs) [p. 9-3]
0x04C
Software watchdog
timer (ICR0) [p. 9-3]
Timer0 (ICR1) [p. 9-3]
Timer1 (ICR2) [p. 9-3]
I2C (ICR3) [p. 9-3]
0x050
UART0 (ICR4) [p. 9-3]
UART1 (ICR5) [p. 9-3]
DMA0 (ICR6) [p. 9-3]
DMA1 (ICR7) [p. 9-3]
0x054
DMA2 (ICR8) [p. 9-3]
DMA3 (ICR9) [p. 9-3]
Reserved
Each internal interrupt source has its own interrupt control register (ICR0–ICR9), shown in
Table 9-2 and described in Section 9.2.1, “Interrupt Control Registers (ICR0–ICR9).”
Table 9-2. Interrupt Control Registers
9-2
MBAR Offset
Register
Name
0x04C
ICR0
Software watchdog timer
0x04D
ICR1
Timer0
0x04E
ICR2
Timer1
0x04F
ICR3
I2C
0x050
ICR4
UART0
0x051
ICR5
UART1
0x052
ICR6
DMA0
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Interrupt Controller Registers
Table 9-2. Interrupt Control Registers (Continued)
MBAR Offset
Register
Name
0x053
ICR7
DMA1
0x054
ICR8
DMA2
0x055
ICR9
DMA3
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Internal interrupts are programmed to a level and priority. Each internal interrupt has a
unique ICR. Each of the 7 interrupt levels has 5 priorities, for a total of 35 possible priority
levels, encompassing internal and external interrupts. The four external interrupt pins offer
seven possible settings at a fixed interrupt level and priority.
The IRQPAR determines these settings for external interrupt request levels. External
interrupts can be programmed to supply an autovector or execute an external interrupt
acknowledge cycle. This is described in Section 9.2.2, “Autovector Register (AVR).”
9.2.1 Interrupt Control Registers (ICR0–ICR9)
The interrupt control registers (ICR0–ICR9) provide bits for defining the interrupt level and
priority for the interrupt source assigned to the ICR, shown in Table 9-2.
7
6
5
Field
AVEC
—
Reset
0
—
R/W
Address
4
3
2
1
0
IL
IP
0_00
00
R/W
MBAR + 0x04C (ICR0); 0x04D (ICR1); 0x04E (ICR2); 0x04F (ICR3); 0x050 (ICR4); 0x051 (ICR5);
0x052 (ICR6); 0x053 (ICR7); 0x054 (ICR8); 0x055 (ICR9)
Figure 9-2. Interrupt Control Registers (ICR0–ICR9)
Table 9-3 describes ICR fields.
Table 9-3. ICRn Field Descriptions
Bits
Field
Description
7
AVEC
Autovector enable. Determines whether the interrupt-acknowledge cycle input (for the internal
interrupt level indicated in IL for each interrupt) requires an autovector response.
0 Interrupting source returns vector during interrupt-acknowledge cycle.
1 SIM generates autovector during interrupt acknowledge cycle.
6–5
—
Reserved, should be cleared.
4–2
IL
Interrupt level. Indicates the interrupt level assigned to each interrupt input. See Table 9-4.
1–0
IP
Interrupt priority. Indicates the interrupt priority for internal modules within the interrupt-level
assignment. See Table 9-4.
00 Lowest
01 Low
10 High
11 Highest
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Interrupt Controller Registers
NOTE:
Assigning the same interrupt level and priority to multiple
ICRs causes unpredictable system behavior.
Table 9-4 shows possible priority schemes for internal and external sources of the
MCF5307. The internal module interrupt source in this table can be any internal interrupt
source programmed to the given level and priority.
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This table shows how external interrupts are prioritized with respect to internal interrupt
sources within the same level. For example, UART0 and UART1 sources are programmed
to IL = 110; in this case, UART0 is given lower priority than UART1, so ICR4[IP] = 01 and
the ICR5[IP] = 10. IRQ3 is programmed to level 6. If all three assert an interrupt request at
the same time, they are serviced in the following order:
1. ICR5[IL] = 110 and ICR5[IP] = 10, so UART1 is serviced first (priority 7 in
Table 9-4).
2. External interrupt IRQ3, set to level 6, is serviced next (priority 8).
3. ICR4[IL] = 110 and ICR5[IP] = 01, so UART0 is serviced last (priority 9).
Table 9-4. Interrupt Priority Scheme
Priority
1
Interrupt
Level
7
2
Interrupt Source
IL
IRQPAR[IRQPAR]
IP
111
11
111
10
Internal module
xxx
xxx
3
xxx
xx
External interrupt pin IRQ7
xxx
4
111
01
Internal module
xxx
5
111
00
6
6
7
110
11
110
10
xxx
Internal module
xxx
xx
External interrupt pin IRQ3 (programmed as IRQ6)
9
110
01
Internal module
10
110
00
12
5
101
11
101
10
xxx
xxx
8
11
9-4
ICR
x1x
xxx
xxx
Internal module
xxx
xxx
13
xxx
xx
External interrupt pin IRQ5
14
101
01
Internal module
15
101
00
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xxx
xxx
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Interrupt Controller Registers
Table 9-4. Interrupt Priority Scheme (Continued)
Priority
ICR
Interrupt
Level
16
Interrupt Source
IL
4
17
100
11
100
10
Internal module
xxx
xxx
18
xxx
xx
External interrupt pin IRQ5 (programmed as IRQ4)
1xx
19
100
01
Internal module
xxx
100
00
011
11
011
10
20
21
3
22
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IRQPAR[IRQPAR]
IP
xxx
Internal module
xxx
xxx
23
xxx
xx
External interrupt pin IRQ3
x0x
24
011
01
Internal module
xxx
011
00
010
11
010
10
25
26
2
27
xxx
Internal module
xxx
xxx
28
xxx
xx
External interrupt pin IRQ1 (programmed as IRQ2)
xx1
29
010
01
Internal module
xxx
010
00
001
11
001
10
30
31
1
32
xxx
Internal module
xxx
xxx
33
xxx
xx
External interrupt pin IRQ1
xx0
34
001
01
Internal module
xxx
35
001
00
xxx
9.2.2 Autovector Register (AVR)
The autovector register (AVR), shown in Figure 9-3, enables external interrupt sources to
be autovectored, using the vector offset defined in Table 2-19 in Section 2.8, “Exception
Processing Overview.” Note that the autovector enable for internal interrupt sources applies
for respective ICRs.
7
Field
Reset
R/W
Address
6
5
4
3
2
AVEC
1
0
BLK
0000_0000
R/W
MBAR + 0x04B
Figure 9-3. Autovector Register (AVR)
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Interrupt Controller Registers
Table 9-5 describes AVR fields.
.
Table 9-5. AVR Field Descriptions
Bit
Name
7–1
AVEC Autovector control. Determines whether the external interrupt at that level is autovectored.
0 Interrupting source returns vector during interrupt-acknowledge cycle.
1 SIM generates autovector during interrupt-acknowledge cycle.
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0
BLK
Description
Block address strobe (AS) for external AVEC access. Available for users who use AS as a global
chip select for peripherals and do not want to enable them during an AVEC cycle.
0 Do not block address strobe.
1 Block address strobe from asserting.
Table 9-6 shows the correlation between AVR[AVEC] and the external interrupts. Note that
an AVECn bit is valid only when the corresponding external interrupt request level is
enabled in the IRQPAR.
Table 9-6. Autovector Register Bit Assignments
Autovector Interrupt Source
Autovector Register Bit Location
Vector Offset
External interrupt request 1
AVEC1
0x64
External interrupt request 2
AVEC2
0x68
External interrupt request 3
AVEC3
0x6C
External interrupt request 4
AVEC4
0x70
External interrupt request 5
AVEC5
0x74
External interrupt request 6
AVEC6
0x78
External interrupt request 7
AVEC7
0x7C
9.2.3 Interrupt Pending and Mask Registers (IPR and IMR)
The interrupt pending register (IPR), Figure 9-4, makes visible the interrupt sources that
have an interrupt pending. The interrupt mask register (IMR), also shown in Figure 9-4, is
used to mask the internal and external interrupt sources.
NOTE:
To mask interrupt sources, first set the core’s status register
interrupt mask level to that of the source being masked in the
IMR. Then, the IMR bit can be masked.
An interrupt is masked by setting, and enabled by clearing, the corresponding IMR bit.
When a masked interrupt occurs, the corresponding IPR bit is still set, but no interrupt
request is passed to the core.
9-6
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Interrupt Controller Registers
31
30
29
28
27
26
25
24
Field
—
Reset
—
R/W
23
22
21
20
19
18
17
16
DMA3 DMA2
1
1
Read-only (IPR); R/W (IMR)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Field DMA1 DMA0 UART1 UART0 I2C TIMER2 TIMER1 SWT EINT7 EINT6 EINT5 EINT4 EINT3 EINT2 EINT1
Reset
1111
1111
1111
R/W
Read-only (IPR); R/W (IMR)
Addr
MBAR + 0x040 (IPR); + 0x044 (IMR)
1
1
—
1
—
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Figure 9-4. Interrupt Pending Register (IPR) and Interrupt Mask Register (IMR)
Table 9-7 describes IPR and IMR fields.
Table 9-7. IPR and IMR Field Descriptions
Bits
Name
31–18
—
17–1
See
Figure
9-4
Description
Reserved, should be cleared.
Interrupt pending/mask. Each bit corresponds to an interrupt source defined by the ICR. The
corresponding IMR bit determines whether an interrupt condition can generate an interrupt. At
every clock, the IPR samples the signal generated by the interrupting source. The corresponding
IPR bit reflects the state of the interrupt signal even if the corresponding IMR bit is set.
0 The corresponding interrupt source is not masked (IMR) and has no interrupt pending (IPR).
1 The corresponding interrupt source is masked (IMR) and has an interrupt pending (IPR)
9.2.4 Interrupt Port Assignment Register (IRQPAR)
The interrupt port assignment register (IRQPAR), shown in Figure 9-5, provides the level
assignment of the primary external interrupt pins—IRQ5, IRQ3, and IRQ1. The setting of
IRQPAR2–IRQPAR0 determines the interrupt level of these external interrupt pins.
7
Field IRQPAR2
6
5
IRQPAR1
IRQPAR0
Reset
4
3
2
1
0
—
0000_0000
R/W
R/W
Address
MBAR + 0x06
Figure 9-5. Interrupt Port Assignment Register (IRQPAR)
Table 9-8 describes IRQPAR fields.
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Interrupt Controller Registers
Table 9-8. IRQPAR Field Descriptions
Bits
Name
Description
IRQPARn
Configures the IRQ pin assignments and priorities
IRQPARn
External Pin
IRQPARn = 0
IRQPARn = 1
IRQPAR2
IRQ5
Level 5
Level 4
IRQPAR1
IRQ3
Level 3
Level 6
IRQPAR0
IRQ1
Level 1
Level 2
4–0
—
Reserved, should be cleared.
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7–5
9-8
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Chapter 10
Chip-Select Module
This chapter describes the MCF5307 chip-select module, including the operation and
programming model of the chip-select registers, which include the chip-select address,
mask, and control registers.
10.1 Overview
The following list summarizes the key chip-select features:
•
•
•
•
Eight independent, user-programmable chip-select signals (CS[7:0]) that can
interface with SRAM, PROM, EPROM, EEPROM, Flash, and peripherals
Address masking for 64-Kbyte to 4-Gbyte memory block sizes
Programmable wait states and port sizes
External master access to chip selects
10.2 Chip-Select Module Signals
Table 10-1 lists signals used by the chip-select module.
Table 10-1. Chip-Select Module Signals
Signal
Description
Chip Selects
(CS[7:0])
Each CSn can be independently programmed for an address location as well as for masking, port
size, read/write burst-capability, wait-state generation, and internal/external termination. Only CS0
is initialized at reset when it acts as a global chip select that allows boot ROM to be at any defined
address space. Port size and termination (internal versus external) and byte enables for CS0 are
configured by the logic levels of D[7:5] when RSTI negates.
Output
Enable (OE)
Interfaces to memory or to peripheral devices and enables a read transfer. It is asserted and
negated on the falling edge of the clock. OE is asserted only when one of the chip selects matches
for the current address decode.
Byte Enables/
Byte Write
Enables
(BE[3:0]/
BWE[3:0])
These multiplexed signals are individually programmed through the byte enable mode bit,
CSCRn[BEM], described in Section 10.4.1.3, “Chip-Select Control Registers (CSCR0–CSCR7).”
These generated signals provide byte data select signals, which are decoded from the transfer
size, A1, and A0 signals in addition to the programmed port size and burstability of the memory
accessed, as Table 10-2 shows.
Table 10-2 shows the interaction of the byte enable/byte-write enables with related signals.
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Table 10-2. Byte Enables/Byte Write Enable Signal Settings
BE1/BWE1
BE2/BWE2
BE3/BWE3
D[31:24]
D[23:16]
D[15:8]
D[7:0]
0
1
1
1
1
0
1
1
1
1
0
0
1
1
1
1
1
0
1
1
1
0
0
0
1
1
1
0
1
1
0
1
1
1
0
0
1
1
1
1
1
1
0
1
1
0
0
0
1
1
1
0
1
1
0
1
1
1
0
1
1
0
1
1
1
1
1
1
0
0
0
0
1
1
1
0
1
0
1
1
1
1
0
0
1
1
1
1
1
0
1
1
1
0
0
0
0
1
1
1
0
0
0
1
1
Port Size
A1
A0
Byte
8-bit
0
0
0
16-bit
32-bit
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BE0/BWE0
Transfer Size
Word
8-bit
16-bit
32-bit
Longword
8-bit
0
0
0
1
1
0
1
1
0
0
0
0
0
1
1
1
0
1
0
1
1
1
1
0
0
1
1
1
1
1
0
1
1
1
0
0
0
0
1
1
1
0
0
0
1
1
32-bit
0
0
0
0
0
0
8-bit
0
0
0
1
1
1
0
1
0
1
1
1
1
0
0
1
1
1
1
1
0
1
1
1
0
0
0
0
1
1
1
0
0
0
1
1
0
0
0
0
0
0
16-bit
Line
0
1
16-bit
32-bit
10.3 Chip-Select Operation
Each chip select has a dedicated set of the following registers for configuration and control.
•
10-2
Chip-select address registers (CSARn) control the base address space of the chip
select. See Section 10.4.1.1, “Chip-Select Address Registers (CSAR0–CSAR7).”
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•
•
Chip-Select Operation
Chip-select mask registers (CSMRn) provide 16-bit address masking and access
control. See Section 10.4.1.2, “Chip-Select Mask Registers (CSMR0–CSMR7).”
Chip-select control registers (CSCRn) provide port size and burst capability
indication, wait-state generation, and automatic acknowledge generation features.
See Section 10.4.1.3, “Chip-Select Control Registers (CSCR0–CSCR7).”
Each CSn can assert during specific CPU space accesses such as interrupt-acknowledge
cycles and each can be accessed by an external master. CS0 is a global chip select after reset
and provides relocatable boot ROM capability.
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10.3.1 General Chip-Select Operation
When a bus cycle is initiated, the MCF5307 first compares its address with the base address
and mask configurations programmed for chip selects 0–7 (configured in CSCR0–CSCR7)
and DRAM block 0 and 1 address and control registers (configured in DACR0 and
DACR1). If the driven address matches a programmed chip select or DRAM block, the
appropriate chip select is asserted or the DRAM block is selected using the specifications
programmed in the respective configuration register. Otherwise, the following occurs:
•
If the address and attributes do not match in CSCR or DACR, the MCF5307 runs an
external burst-inhibited bus cycle with a default of external termination on a 32-bit
port.
•
Should an address and attribute match in multiple CSCRs, the matching chip-select
signals are driven; however, the MCF5307 runs an external burst-inhibited bus cycle
with external termination on a 32-bit port.
•
Should an address and attribute match both DACRs or a DACR and a CSCR, the
operation is undefined.
Table 10-3 shows the type of access as a function of match in the CSCRs and DACRs.
Table 10-3. Accesses by Matches in CSCRs and DACRs
Number of CSCR Matches
Number of DACR Matches
Type of Access
0
0
External
1
0
Defined by CSCR
Multiple
0
External, burst-inhibited, 32-bit
0
1
Defined by DACRs
1
1
Undefined
Multiple
1
Undefined
0
Multiple
Undefined
1
Multiple
Undefined
Multiple
Multiple
Undefined
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10.3.1.1 8-, 16-, and 32-Bit Port Sizing
Static bus sizing is programmable through the port size bits, CSCR[PS]. See
Section 10.4.1.3, “Chip-Select Control Registers (CSCR0–CSCR7).” Figure 10-1 shows
the correspondence between data byte lanes and the external chip-select memory. Note that
all lanes are driven, although unused lines are undefined.
BE0
BE1
BE2
BE3
D[31:24]
D[23:16]
D[15:8]
D[7:0]
32-bit port
memory
Byte 0
Byte 1
Byte 2
Byte 3
16-bit port
memory
Byte 0
Byte 1
Byte 2
Byte 3
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External
data bus
8-bit port
memory
Byte 0
Byte 1
Byte 2
Byte 3
Driven, undefined
Driven, undefined
Figure 10-1. Connections for External Memory Port Sizes
10.3.1.2 Global Chip-Select Operation
CS0, the global (boot) chip select, allows address decoding for boot ROM before system
initialization. Its operation differs from other external chip-select outputs after system reset.
After system reset, CS0 is asserted for every external access. No other chip-select can be
used until the valid bit, CSMR0[V], is set, at which point CS0 functions as configured and
CS[7:1] can be used. At reset, the port size and automatic acknowledge functions of the
global chip-select are determined by the logic levels of the inputs on D[7:5]. Table 10-4 and
Table 10-5list the various reset encodings for the configuration signals multiplexed with
D[7:5].
Table 10-4. D7/AA, Automatic Acknowledge of Boot CS0
D7/AA
Boot CS0 AA Configuration at Reset
0
Disabled
1
Enable with 15 wait states
Provided the required address range is in the chip-select address register (CSAR0), CS0 can
Table 10-5. D[6:5]/PS[1:0], Port Size of Boot CS0
10-4
D[6:5]/PS[1:0]
Boot CS0 Port Size at Reset
00
32-bit port
01
8-bit port
1x
16-bit port
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Chip-Select Registers
be programmed to continue decoding for a range of addresses after the CSMR0[V] is set,
after which the global chip-select can be restored only by a system reset.
10.4 Chip-Select Registers
Table 10-6Table 10-6 is the chip-select register memory map. Reading reserved locations
returns zeros.
Table 10-6. Chip-Select Registers
MBAR
Offset
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0x080
0x084
[31:24]
[23:16]
[15:8]
[7:0]
Reserved1
Chip-select address register—bank 0 (CSAR0) [p. 10-6]
Chip-select mask register—bank 0 (CSMR0) [p. 10-6]
0x088
Reserved1
Chip-select control register—bank 0
(CSCR0) [p. 10-8]
0x08C
Chip-select address register—bank 1 (CSAR1) [p. 10-6]
Reserved1
0x090
Chip-select mask register—bank 1 (CSMR1) [p. 10-6]
0x094
Reserved1
Chip-select control register—bank 1
(CSCR1) [p. 10-8]
0x098
Chip-select address register—bank 2 (CSAR2) [p. 10-6]
Reserved1
0x09C
Chip-select mask register—bank 2 (CSMR2) [p. 10-6]
0x0A0
Reserved1
Chip-select control register—bank 2
(CSCR2) [p. 10-8]
0x0A4
Chip-select address register—bank 3 (CSAR3) [p. 10-6]
Reserved1
0x0A8
Chip-select mask register—bank 3 (CSMR3) [p. 10-6]
0x0AC
Reserved1
Chip-select control register—bank 3
(CSCR3) [p. 10-8]
0x0B0
Chip-select address register—bank 4 (CSAR4) [p. 10-6]
Reserved1
0x0B4
Chip-select mask register—bank 4 (CSMR4) [p. 10-6]
0x0B8
Reserved1
Chip-select control register—bank 4
(CSCR4) [p. 10-8]
0x0BC
Chip-select address register—bank 5 (CSAR5) [p. 10-6]
Reserved1
0x0C0
Chip-select mask register—bank 5 (CSMR5) [p. 10-6]
0x0C4
Reserved
Chip-select control register—bank 5
(CSCR5) [p. 10-8]
0x0C8
Chip-select address register—bank 6 (CSAR6) [p. 10-6]
Reserved1
0x0CC
Chip-select mask register—bank 6 (CSMR6) [p. 10-6]
0x0D0
Reserved1
Chip-select control register—bank 6
(CSCR6) [p. 10-8]
0x0D4
Chip-select address register—bank 7 (CSAR7) [p. 10-6]
Reserved1
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Chip-Select Registers
Table 10-6. Chip-Select Registers (Continued)
MBAR
Offset
[31:24]
0x0D8
[15:8]
[7:0]
Chip-select mask register—bank 7 (CSMR7) [p. 10-6]
Reserved1
0x0DC
1
[23:16]
Chip-select control register—bank 7
(CSCR7) [p. 10-8]
Addresses not assigned to a register and undefined register bits are reserved for expansion. Write accesses to
these reserved address spaces and reserved register bits have no effect.
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NOTE:
External masters cannot access MCF5307 on-chip memories or
MBAR, but can access any of the chip-select module registers.
10.4.1 Chip-Select Module Registers
The chip-select module is programmed through the chip select address registers
(CSAR0–CSAR7), chip select mask registers (CSMR0–CSMR7), and the chip select
control registers (CSCR0–CSCR7).
10.4.1.1 Chip-Select Address Registers (CSAR0–CSAR7)
Chip select address registers, Figure 10-2, specify the chip select base addresses.
15
0
Field
BA
Reset
Uninitialized
R/W
R/W
Addr
0x080 (CSAR0); 0x08C (CSAR1); 0x098 (CSAR2); 0x0A4 (CSAR3);
0x0B0 (CSAR4); 0x0BC (CSAR5); 0x0C8 (CSAR6); 0x0D4 (CSAR7)
Figure 10-2. Chip Select Address Registers (CSAR0–CSAR7)
Table 10-7 describes CSAR[BA].
Table 10-7. CSARn Field Description
Bits
Name
Description
15–0
BA
Base address. Defines the base address for memory dedicated to chip select CS[7:0]. BA is compared
to bits 31–16 on the internal address bus to determine if chip-select memory is being accessed.
10.4.1.2 Chip-Select Mask Registers (CSMR0–CSMR7)
The chip select mask registers, Figure 10-3, are used to specify the address mask and
allowable access types for the respective chip selects.
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Chip-Select Registers
.
31
16 15
Field
9
BAM
—
Reset
8
7
6
5
4
3
2
1
0
WP — AM C/I SC SD UC UD V
Unitialized
R/W
R/W
Addr
0x084 (CSMR0); 0x090 (CSMR1); 0x09C (CSMR2); 0x0A8 (CSMR3);
0x0B4 (CSMR4); 0x0C0 (CSMR5); 0x0CC (CSMR6); 0x0D8 (CSMR7)
0
Figure 10-3. Chip Select Mask Registers (CSMRn)
Table 10-8 describes CSMR fields.
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Table 10-8. CSMRn Field Descriptions
Bits
Name
Description
31–16
BAM
Base address mask. Defines the chip select block by masking address bits. Setting a BAM bit
causes the corresponding CSAR bit to be ignored in the decode.
0 Corresponding address bit is used in chip-select decode.
1 Corresponding address bit is a don’t care in chip-select decode.
The block size for CS[7:0] is 2n; n = (number of bits set in respective CSMR[BAM]) + 16.
So, if CSAR0 = 0x0000 and CSMR0[BAM] = 0x0008, CS0 would address two discontinuous
64-Kbyte memory blocks: one from 0x0000–0xFFFF and one from 0x8_0000–0x8_FFFF.
Likewise, for CS0 to access 32 Mbytes of address space starting at location 0x0, CS1 must begin
at the next byte after CS0 for a 16-Mbyte address space. Then CSAR0 = 0x0000,
CSMR0[BAM] = 0x01FF, CSAR1 = 0x0200, and CSMR1[BAM] = 0x00FF.
8
WP
Write protect. Controls write accesses to the address range in the corresponding CSAR.
Attempting to write to the range of addresses for which CSARn[WP] = 1 results in the appropriate
chip select not being selected. No exception occurs.
0 Both read and write accesses are allowed.
1 Only read accesses are allowed.
7
—
Reserved, should be cleared.
6
AM
Alternate master. When AM = 0 during an external master or DMA access, SC, SD, UC, and UD
are don’t cares in the chip-select decode.
5–1
C/I,
SC,
SD,
UC,
UD
Address space mask bits. These bits determine whether the specified accesses can occur to the
address space defined by the BAM for this chip select.
C/I
SC
SD
UC
UD
CPU space and interrupt acknowledge cycle mask
Supervisor code address space mask
Supervisor data address space mask
User code address space mask
User data address space mask
0 The address space assigned to this chip select. is available to the specified access type.
1 The address space assigned to this chip select. is not available (masked) to the specified access
type. If this address space is accessed, chip select is not activated and a regular external bus
cycle occurs.
Note that if if AM = 0, SC, SD, UC, and UD are ignored in the chip select decode on external
master or DMA access.
0
V
Valid bit. Indicates whether the corresponding CSAR, CSMR, and CSCR contents are valid.
Programmed chip selects do not assert until V is set (except for CS0, which acts as the global chip
select). Reset clears each CSMRn[V].
0 Chip select invalid
1 Chip select valid
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Chip-Select Registers
10.4.1.3 Chip-Select Control Registers (CSCR0–CSCR7)
Each chip-select control register, Figure 10-4, controls the auto acknowledge, external
master support, port size, burst capability, and activation of each chip select. Note that to
support the global chip select, CS0, the CSCR0 reset values differ from the other CSCRs.
CS0 allows address decoding for boot ROM before system initialization.
15
14
13
10
8
7
6
5
4
3
2
—
WS
—
AA PS1 PS0 BEM BSTR BSTW
Reset: CSCR0
—
11_11
—
D7
Reset: Other CSCRs
Address
D6
D5
—
0
—
—
Unitialized
R/W
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9
Field
R/W
0x08A (CSCR0); 0x096 (CSCR1); 0x0A2 (CSCR2); 0x0AE (CSCR3);
0x0BA (CSCR4); 0x0C6 (CSCR5); 0x0D2 (CSCR6); 0x0DE (CSCR7)
Figure 10-4. Chip-Select Control Registers (CSCR0–CSCR7)
Table 10-9 describes CSCRn fields.
Table 10-9. CSCRn Field Descriptions
Bits
Name
15–14
—
13–10
WS
Description
Reserved, should be cleared.
Wait states. The number of wait states inserted before an internal transfer acknowledge is generated
(WS = 0 inserts zero wait states, WS = 0xF inserts 15 wait states). If AA = 0, TA must be asserted by
the external system regardless of the number of wait states generated. In that case, the external
transfer acknowledge ends the cycle. An external TA supersedes the generation of an internal TA.
9
—
Reserved, should be cleared.
8
AA
Auto-acknowledge enable. Determines the assertion of the internal transfer acknowledge for
accesses specified by the chip-select address.
0 No internal TA is asserted. Cycle is terminated externally.
1 Internal TA is asserted as specified by WS. Note that if AA = 1 for a corresponding CSn and the
external system asserts an external TA before the wait-state countdown asserts the internal TA, the
cycle is terminated. Burst cycles increment the address bus between each internal termination.
7–6
PS
Port size. Specifies the width of the data associated with each chip select. It determines where data
is driven during write cycles and where data is sampled during read cycles. See Section 10.3.1.1,
“8-, 16-, and 32-Bit Port Sizing.”
00 32-bit port size. Valid data sampled and driven on D[31:0]
01 8-bit port size. Valid data sampled and driven on D[31:24]
1x 16-bit port size. Valid data sampled and driven on D[31:16]
5
BEM
Byte enable mode. Specifies the byte enable operation. Certain SRAMs have byte enables that must
be asserted during reads as well as writes. BEM can be set in the relevant CSCR to provide the
appropriate mode of byte enable in support of these SRAMs.
0 Neither BE nor BWE is asserted for read. BWE is generated for data write only.
1 BE is asserted for read; BWE is asserted for write.
4
BSTR
Burst read enable. Specifies whether burst reads are used for memory associated with each CSn.
0 Data exceeding the specified port size is broken into individual, port-sized non-burst reads. For
example, a longword read from an 8-bit port is broken into four 8-bit reads.
1 Enables data burst reads larger than the specified port size, including longword reads from 8- and
16-bit ports, word reads from 8-bit ports, and line reads from 8-, 16-, and 32-bit ports.
10-8
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Chip-Select Registers
Table 10-9. CSCRn Field Descriptions
Bits
3
Name
Description
BSTW Burst write enable. Specifies whether burst writes are used for memory associated with each CSn.
0 Break data larger than the specified port size into individual port-sized, non-burst writes. For
example, a longword write to an 8-bit port takes four byte writes.
1 Enables burst write of data larger than the specified port size, including longword writes to 8 and
16-bit ports, word writes to 8-bit ports and line writes to 8-, 16-, and 32-bit ports.
2–0
—
Reserved, should be cleared.
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10.4.1.4 Code Example
The code below provides an example of how to initialize the chip-selects. Only chip selects
0, 1, 2, and 3 are programmed here; chip selects 4, 5, 6, and 7 are left invalid. MBARx
defines the base of the module address space.
CSAR0 EQU MBARx+0x080
CSMR0 EQU MBARx+0x084
CSCR0 EQU MBARx+0x08A
;Chip select 0 address register
;Chip select 0 mask register
;Chip select 0 control register
CSAR1 EQU MBARx+0x08C
CSMR1 EQU MBARx+0x090
CSCR1 EQU MBARx+0x096
;Chip select 1 address register
;Chip select 1 mask register
;Chip select 1 control register
CSAR2 EQU MBARx+0x098
CSMR2 EQU MBARx+0x09C
CSCR2 EQU MBARx+0x0A2
;Chip select 2 address register
;Chip select 2 mask register
;Chip select 2 control register
CSAR3 EQU MBARx+0x0A4
CSMR3 EQU MBARx+0x0A8
CSCR3 EQU MBARx+0x0AE
;Chip select 3 address register
;Chip select 3 mask register
;Chip select 3 control register
CSAR4 EQU MBARx+0x0B0
CSAR4 EQU MBARx+0x0B4
CSMR4 EQU MBARx+0x0BA
;Chip select 4 address register
;Chip select 4 mask register
;Chip select 4 control register
CSAR5 EQU MBARx+0x0BC
CSMR5 EQU MBARx+0x0C0
CSCR5 EQU MBARx+0x0C6
;Chip select 5 address register
;Chip select 5 mask register
;Chip select 5 control register
CSAR6 EQU MBARx+0x0C8
CSMR6 EQU MBARx+0x0CC
CSCR6 EQU MBARx+0x0D2
;Chip select 6 address register
;Chip select 6 mask register
;Chip select 6 control register
CSAR7 EQU MBARx+0x0D4
CSMR7 EQU MBARx+0x0D8
CSCR7 EQU MBARx+0x0DE
;Chip select 7 address register
;Chip select 7 mask register
;Chip select 7 control register
; All other chip selects should be programmed and made valid before global
; chip select is de-activated by validating CS0
; Program Chip Select 3 Registers
move.w #0x0040,D0
;CSAR3 base address 0x00400000
move.w D0,CSAR3
move.w
move.w
#0x00A0,D0
D0,CSCR3
move.l #0x001F016B,D0
move.l D0,CSMR3
;CSCR3 = no wait states, AA=0, PS=16-bit, BEM=1,
;BSTR=0, BSTW=0
;Address range from 0x00400000 to 0x005FFFFF
;WP,EM,C/I,SD,UD,V=1; SC,UC=0
; Program Chip Select 2 Registers
move.w
#0x0020,D0
;CSAR2 base address 0x00200000 (to 0x003FFFFF)
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Chip-Select Registers
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move.w
D0,CSAR2
move.w
move.w
#0x0538,D0
D0,CSCR2
;CSCR2 = 1 wait state, AA=1, PS=32-bit, BEM=1,
;BSTR=1, BSTW=1
move.l
move.l
#0x001F0001,D0
D0,CSMR2
;Address range from 0x00200000 to 0x003FFFFF
;WP,EM,C/I,SC,SD,UC,UD=0; V=1
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; Program Chip Select 1 Registers
move.w
move.w
#0x0000,D0
D0,CSAR1
;CSAR1 base addresses 0x00000000 (to 0x001FFFFF)
;and 0x80000000 (to 0x801FFFFF)
move.w
move.w
#0x09B0,D0
D0,CSCR1
;CSCR1 = 2 wait states, AA=1, PS=16-bit, BEM=1,
;BSTR=1, BSTW=0
move.l
move.l
#0x801F0001,D0
D0,CSMR1
;Address range from 0x00000000 to 0x001FFFFF and
;0x80000000 to 0x801FFFFF
;WP, EM, C/I, SC, SD, UC, UD=0, V=1
; Program Chip Select 0 Registers
move.w
move.w
#0x0080,D0
D0,CSAR0
;CSAR0 base address 0x00800000 (to 0x009FFFFF)
move.w
move.w
#0x0D80,D0
D0,CSCR0
;CSCR0 = three wait states, AA=1, PS=16-bit, BEM=0,
;BSTR=0, BSTW=0
; Program Chip Select 0 Mask Register (validate chip selects)
move.l
move.l
10-10
#0x001F0001,D0
D0,CSMR0
;Address range from 0x00800000 to 0x009FFFFF
;WP,EM,C/I,SC,SD,UC,UD=0; V=1
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Chapter 11
Synchronous/Asynchronous DRAM
Controller Module
This chapter describes configuration and operation of the synchronous/asynchronous
DRAM controller component of the system integration module (SIM). It begins with a
general description and brief glossary, and includes a description of signals involved in
DRAM operations. The remainder of the chapter consists of the two following parts:
•
•
Section 11.3, “Asynchronous Operation,” describes the programming model and
signal timing for the four basic asynchronous modes.
— Non-page mode
— Burst page mode
— Continuous page mode
— Extended data-out mode
Section 11.4, “Synchronous Operation,” describes the programming model and
signal timing, as well as the command set required for synchronous operations. This
section also includes extensive examples the designer can follow to better
understand how to configure the DRAM controller for synchronous operations.
11.1 Overview
The DRAM controller module provides glueless integration of DRAM with the ColdFire
product. The key features of the DRAM controller include the following:
•
•
•
•
•
•
Support for two independent blocks of DRAM
Interface to standard synchronous/asynchronous dynamic random access memory
(ADRAM/SDRAM) components
Programmable SRAS, SCAS, and refresh timing
Support for page mode
Support for 8-, 16-, and 32-bit wide DRAM blocks
Support for synchronous and asynchronous DRAMs, including EDO DRAM,
SDRAM, and fast page mode
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Overview
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11.1.1 Definitions
The following terminology is used in this chapter:
•
•
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•
A/SDRAM block—Any group of DRAM memories selected by one of the
MCF5307 RAS[1:0] signals. Thus, the MCF5307 can support two independent
memory blocks. The base address of each block is programmed in the DRAM
address and control registers (DACR0 and DACR1).
SDRAM—RAMs that operate like asynchronous DRAMs but with a synchronous
clock, a pipelined, multiple-bank architecture, and faster speed.
SDRAM bank—An internal partition in an SDRAM device. For example, a 64-Mbit
SDRAM component might be configured as four 512K x 32 banks. Banks are
selected through the SDRAM component’s bank select lines.
11.1.2 Block Diagram and Major Components
The basic components of the DRAM controller are shown in Figure 11-1.
DRAM Controller Module
A[31:0]
Address
Multiplexing
Internal
Bus
Page Hit
Logic
Control Logic
and
State Machine
Memory Block 0 Hit Logic
DRAM Address/Control Register 0
(DACR0)
DRAM Control
Register (DCR)
Memory Block 1 Hit Logic
DRAM Address/Control Register 1
(DACR1)
A[31:0]
RAS[1:0]
CAS[3:0]
DRAMW
SCAS
These signals
are used for
SRAS
SDRAM only
SCKE
Refresh Counter
Figure 11-1. Asynchronous/Synchronous DRAM Controller Block Diagram
The DRAM controller’s major components, shown in Figure 11-1, are described as
follows:
•
11-2
DRAM address and control registers (DACR0 and DACR1)—The DRAM
controller consists of two configuration register units, one for each supported
memory block. DACR0 is accessed at MBAR + 0x0108; DACR1 is accessed at
0x010. The register information is passed on to the hit logic.
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DRAM Controller Operation
•
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•
•
•
Control logic and state machine—Generates all DRAM signals, taking bus cycle
characteristic data from the block logic, along with hit information to generate
DRAM accesses. Handles refresh requests from the refresh counter.
— DRAM control register (DCR)—Contains data to control refresh operation of
the DRAM controller. Both memory blocks are refreshed concurrently as
controlled by DCR[RC].
— Refresh counter—Determines when refresh should occur, determined by the
value of DCR[RC]. It generates a refresh request to the control block.
Hit logic—Compares address and attribute signals of a current DRAM bus cycle to
both DACRs to determine if a DRAM block is being accessed. Hits are passed to the
control logic along with characteristics of the bus cycle to be generated.
Page hit logic—Determines if the next DRAM access is in the same DRAM page as
the previous one. This information is passed on to the control logic.
Address multiplexing—Multiplexes addresses to allow column and row addresses
to share pins. This allows glueless interface to DRAMs.
11.2 DRAM Controller Operation
The DRAM controller mode is programmed through DCR[SO]. Asynchronous mode
(SO = 0) includes support for page mode and EDO DRAMs. Synchronous mode is
designed to work with industry-standard SDRAMs. These modes act very differently from
one another, especially regarding the use of DRAM registers and pins. Memory blocks
cannot operate in different modes; both are either synchronous or asynchronous.
11.2.1 DRAM Controller Registers
The DRAM controller registers memory map, Table 11-1, is the same regardless of whether
asynchronous or synchronous DRAM is used, although bit configurations may vary.
Table 11-1. DRAM Controller Registers
MBAR
Offset
0x100
[31:24]
[23:16]
[15:8]
DRAM control register (DCR) [p. 11-4]
[7:0]
Reserved
0x104
Reserved
0x108
DRAM address and control register 0 (DACR0) [p. 11-5]
0x10C
DRAM mask register block 0 (DMR0) [p. 11-7]
0x110
DRAM address and control register 1 (DACR1) [p. 11-5]
0x114
DRAM mask register block 1 (DMR1) [p. 11-7]
NOTE:
External masters cannot access MCF5307 on-chip memories or
MBAR, but they can access DRAM controller registers.
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11-3
Asynchronous Operation
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11.3 Asynchronous Operation
The DRAM controller supports asynchronous DRAMs for cost-effective systems. Typical
access times for the DRAM controller interfacing to ADRAM are 4-3-3-3. The DRAM
controller supports the following four asynchronous modes:
Freescale Semiconductor, Inc...
•
•
•
•
Non-page mode
Burst page mode
Continuous page mode
Extended data-out mode
In asynchronous mode, RAS and CAS always transition at the falling clock edge. As
summarized previously, operation and timing of each ADRAM block is controlled by
separate registers, but refresh is the same for both. All ADRAM accesses should be
terminated by the DRAM controller. There is no priority encoding between memory
blocks, so programming blocks to overlap with other blocks or with other internal resources
causes undefined behavior.
11.3.1 DRAM Controller Signals in Asynchronous Mode
Table 11-2 summarizes DRAM signals used in asynchronous mode.
Table 11-2. SDRAM Signal Summary
Signal
Description
RAS[1:0]
Row address strobes. Interface to RAS inputs on industry-standard ADRAMs. When SDRAMs are used,
these signals interface to the chip-select lines within an SDRAM’s memory block. Thus, there is one RAS
line for each of the two blocks.
CAS[3:0]
Column address strobes. Interface to CAS inputs on industry-standard DRAMs. These provide CAS for
a given ADRAM block. When SDRAMs are used, CAS[3:0] control the byte enables (DQMx) for standard
SDRAMs. CAS[3:0] strobes data in least-to-most significant byte order (CAS0 is MSB).
DRAMW
DRAM read/write. Asserted when a DRAM write cycle is underway. Negated for read bus cycles.
11.3.2 Asynchronous Register Set
The following register configurations apply when DCR[SO] is 0, indicating the DRAM
controller is interfacing to asynchronous DRAMs.
11.3.2.1 DRAM Control Register (DCR) in Asynchronous Mode
The DCR provides programmable options for the refresh logic as well as the control bit to
determine if the module is operating with synchronous or asynchronous DRAMs. The DCR
is shown in Figure 11-2.
11-4
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Asynchronous Operation
15
Field SO
Reset
14
13
—
NAM
12
11
10
RRA
0
9
8
0
RRP
RC
Uninitialized
R/W
R/W
Address
MBAR + 0x100
Figure 11-2. DRAM Control Register (DCR) (Asynchronous Mode)
Table 11-3 describes DCR fields.
Table 11-3. DCR Field Descriptions (Asynchronous Mode)
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Bits
Name
Description
15
SO
Synchronous operation. Selects synchronous or asynchronous mode. A DRAM controller in
synchronous mode can be switched to ADRAM mode only by resetting the MCF5307.
0 Asynchronous DRAMs. Default at reset.
1 Synchronous DRAMs
14
—
Reserved, should be cleared.
13
NAM
No address multiplexing. Some implementations require external multiplexing. For example, when
linear addressing is required, the DRAM should not multiplex addresses on DRAM accesses.
0 The DRAM controller multiplexes the external address bus to provide column addresses.
1 The DRAM controller does not multiplex the external address bus to provide column addresses.
12–11
RRA
Refresh RAS asserted. Determines how long RAS is asserted during a refresh operation.
00 2 clocks
01 3 clocks
10 4 clocks
11 5 clocks
10–9
RRP
Refresh RAS precharge. Controls how many clocks RAS is precharged after a refresh operation
before accesses are allowed to DRAM.
00 1 clock
01 2 clocks
10 3 clocks
11 4 clocks
8–0
RC
Refresh count. Controls refresh frequency. The number of bus clocks between refresh cycles is
(RC + 1) * 16. Refresh can range from 16–8192 bus clocks to accommodate both standard and
low-power DRAMs with bus clock operation from less than 2 MHz to greater than 50 MHz.
The following example calculates RC for an auto-refresh period for 4096 rows to receive 64 mS of
refresh every 15.625 µs for each row (625 bus clocks at 40 MHz).
# of bus clocks = 625 = (RC field + 1) * 16
RC = (625 bus clocks/16) -1 = 38.06, which rounds to 38; therefore, RC = 0x26.
11.3.2.2 DRAM Address and Control Registers (DACR0/DACR1)
DACR0 and DACR1, Figure 11-3, contain the base address compare value and the control
bits for memory blocks 0 and 1. Address and timing are also controlled by these registers.
Memory areas defined for each block should not overlap; operation is undefined for
accesses in overlapping regions.
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31
18 17 16
Field
BA
Reset
—
Unitialized
15
14 13 12 11 10
RE — CAS
RP
9
RNCN
0
8
7
6
RCD — EDO
5
4
PS
3
2
PM
1
0
—
Unitialized
R/W
R/W
Addr
MBAR + 0x10C (DACR0); 0x110 (DACR1)
Figure 11-3. DRAM Address and Control Registers (DACR0/DACR1)
Table 11-4 describes DACRn fields.
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Table 11-4. DACR0/DACR1 Field Description
Bits
Name
Description
31–18
BA
Base address. Used with DMR[BAM] to determine the address range in which the associated
DRAM block is located. Each BA bit is compared with the corresponding address of the bus cycle in
progress. If each bit matches, or if bits that do not match are masked in the BAM, the address
selects the associated DRAM block.
17–16
—
Reserved, should be cleared.
15
RE
Refresh enable. Determines whether the DRAM controller generates a refresh to the associated
DRAM block. DRAM contents are not preserved during hard reset or software watchdog reset.
0 Do not refresh associated DRAM block. (Default at reset)
1 Refresh associated DRAM block.
Reserved, should be cleared.
14
—
13–12
CAS
11–10
RP
9
RAS precharge timing. Determines how long RAS is precharged between accesses. Note that RP
is different from DCR[RRP].
00 1 clock cycle
01 2 clock cycles
10 3 clock cycles
11 4 clock cycles
RNCN RAS-negate-to-CAS-negate. Controls whether RAS and CAS negate concurrently or one clock
apart. RNCN is ignored if CAS is asserted for only one clock and both RAS and CAS are negated.
RNCN is used only for non-page-mode accesses and single accesses in page mode.
0 RAS negates concurrently with CAS.
1 RAS negates one clock before CAS.
8
RCD
7
—
6
EDO
11-6
CAS timing. Determines how long CAS is asserted during a DRAM access.
00 1 clock cycle
01 2 clock cycles
10 3 clock cycles
11 4 clock cycles
RAS-to-CAS delay. Determines the number of system clocks between assertions of RAS and CAS.
0 1 clock cycle
1 2 clock cycles
Reserved, should be cleared.
Extended data out. Determines whether the DRAM block operates in a mode to take advantage of
industry-standard EDO DRAMs. Do not use EDO mode with non-EDO DRAM.
0 EDO operation disabled.
1 EDO operation enabled.
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Table 11-4. DACR0/DACR1 Field Description (Continued)
Bits
Name
Description
5–4
PS
Port size. Determines the port size of the associated DRAM block. For example, if two 16-bit wide
DRAM components form one DRAM block, the port size is 32 bits. Programming PS allows the
DRAM controller to execute dynamic bus sizing for associated accesses.
00 32-bit port
01 8-bit port
1x 16-bit port
3–2
PM
Page mode. Configures page-mode operation for the memory block.
00 No page mode
01 Burst page mode (page mode for bursts only)
10 Reserved
11 Continuous page mode
1–0
—
Reserved, should be cleared.
11.3.2.3 DRAM Controller Mask Registers (DMR0/DMR1)
The DRAM controller mask registers (DMR0 and DMR1), shown in Figure 11-4, include
mask bits for the base address and for address attributes.
31
18 17
Field
BAM
9
—
Reset
8
7
6
5
4
3
2
1
0
WP — C/I AM SC SD UC UD V
Uninitialized
R/W
R/W
Addr
MBAR + 0x10C (DMR0), 0x114 (DMR1)
0
Figure 11-4. DRAM Controller Mask Registers (DMR0 and DMR1)
Table 11-5 describes DMRn fields.
Table 11-5. DMR0/DMR1 Field Descriptions
Bits
Name
Description
31–18
BAM
Base address mask. Masks the associated DACRn[BA]. Lets the DRAM controller connect to various
DRAM sizes. Mask bits need not be contiguous (see Section 11.5, “SDRAM Example.”)
0 The associated address bit is used in decoding the DRAM hit to a memory block.
1 The associated address bit is not used in the DRAM hit decode.
17–9
—
8
WP
7
—
Reserved, should be cleared.
Write protect. Determines whether the associated block of DRAM is write protected.
0 Allow write accesses
1 Ignore write accesses. The DRAM controller ignores write accesses to the memory block and an
address exception occurs. Write accesses to a write-protected DRAM region are compared in the
chip select module for a hit. If no hit occurs, an external bus cycle is generated. If this external bus
cycle is not acknowledged, an access exception occurs.
Reserved, should be cleared.
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Table 11-5. DMR0/DMR1 Field Descriptions (Continued)
Bits
Name
6–1
AMx
Description
Address modifier masks. Determine which accesses can occur in a given DRAM block.
0 Allow access type to hit in DRAM
1 Do not allow access type to hit in DRAM
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Bit
0
V
Associated Access Type
Access Definition
C/I
CPU space/interrupt acknowledge
MOVEC instruction or interrupt acknowledge cycle
AM
Alternate master
External or DMA master
SC
Supervisor code
Any supervisor-only instruction access
SD
Supervisor data
Any data fetched during the instruction access
UC
User code
Any user instruction
UD
User data
Any user data
Valid. Cleared at reset to ensure that the DRAM block is not erroneously decoded.
0 Do not decode DRAM accesses.
1 Registers controlling the DRAM block are initialized; DRAM accesses can be decoded.
11.3.3 General Asynchronous Operation Guidelines
The DRAM controller provides control for RAS, CAS, and DRAMW signals, as well as
address multiplexing and bus cycle termination. Whether the mode is synchronous or
asynchronous determines signal control and termination. To reduce complexity,
multiplexing is the same for both modes. Table 11-6 shows the scheme for DRAM
configurations. This scheme works for symmetric configurations (in which the number of
rows equals the number of columns) as well as asymmetric configurations (in which the
number of rows and columns are different).
Table 11-6. Generic Address Multiplexing Scheme
Address Pin
Row Address
Column Address
17
17
0
8-bit port only
16
16
1
8- and 16-bit ports only
15
15
2
14
14
3
13
13
4
12
12
5
11
11
6
10
10
7
11-8
Notes Relating to Port Sizes
9
9
8
17
17
16
32-bit port only
18
18
17
16-bit port only or 32-bit port with only 8 column address lines
19
19
18
16-bit port only when at least 9 column address lines are used
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Table 11-6. Generic Address Multiplexing Scheme (Continued)
Address Pin
Row Address
Column Address
20
20
19
21
21
20
22
22
21
23
23
22
24
24
23
25
25
24
Notes Relating to Port Sizes
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Note the following:
•
•
•
•
•
Each MCF5307 address bit drives both a row address and a column address bit.
As the user upgrades ADRAM, corresponding MCF5307 address bits must be
connected. This multiplexing scheme allows various memory widths to be
connected to the address bus.
Some differences exist for each of the three possible port sizes. Note that only 8-bit
ports use an A0 address from the MCF5307. Because 16- and 32-bit ports issue
either words or longwords when accessed, they do not use the MCF5307 A0 signal.
Likewise, the configuration for 32-bit ports uses neither A0 or A1. This presents a
slight problem because DRAM address signal A0 is issued on physical pin A17 of
the MCF5307 along with the ADRAM address signal A17. Although A0 is not used
for larger ports, A17 is still needed. The MCF5307 DRAM controller provides for
this by changing the column address that appears on physical pin A17 of the
processor whenever an 8-bit port is not selected. This is determined by the
DACRn[PS] settings. For 8-bit ports, MCF5307 physical pin A17 drives logical
address A0 during the CAS cycle. When 16- or 32-bit port sizes are programmed,
the CAS cycle pin A17 drives logical address A16, as indicated in the generic
connection scheme.
If a 32-bit port is used with only eight column address lines, A18 must drive DRAM
address bit A18. Otherwise, in 32-bit port configurations, the MCF5307 physical
address line is not connected with more than eight column address lines.
All ADRAM blocks have a fixed page size of 512 bytes for page-mode operation.
The addresses are connected differently for various width combinations.
Table 11-7, Table 11-8, and Table 11-9 show how 8-, 16-, and 32-bit symmetrical ADRAM
memories are connected to the address bus. The memory sizes show what DRAM size is
accessed if the corresponding bits are connected to the memory. In each case, there is a base
memory size. This limitation exists to allow simple page-mode multiplexing. Notice also
that MCF5307 pin 17 is treated differently in byte-wide operations. In byte-wide
operations, address bits 16 and 17 are driven on MCF5307 physical address pins 16 and 17,
rather than the two bits being driven solely on A17, as they are for 32-wide memories.
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Table 11-7. DRAM Addressing for Byte-Wide Memories
MCF5307 Address Pin
MCF5307 Address Bit
Driven for RAS
MCF5307 Address Bit Driven
when CAS is Asserted
17
17
0
16
16
1
15
15
2
14
14
3
13
13
4
12
12
5
11
11
6
10
10
7
9
9
8
19
19
18
1 Mbyte
21
21
20
4 Mbytes
23
23
22
16 Mbytes
25
25
24
64 Mbytes
Memory Size
Base memory size of
256 Kbytes
Note that in Table 11-8, MCF5307 pin A19 is not connected because DRAM address bit 18
is already provided on MCF5307 pin A18; thus, the next MCF5307 pin used should be A20.
Table 11-8. DRAM Addressing for 16-Bit Wide Memories
MCF5307 Address Pin
MCF5307 Address Bit
Driven for RAS
MCF5307 Address Bit Driven
when CAS is Asserted
16
16
1
15
15
2
14
14
3
13
13
4
12
12
5
11
11
6
10
10
7
9
9
8
18
18
17
512 Kbytes
20
20
19
2 Mbytes
22
22
21
8 Mbytes
24
24
23
32 Mbytes
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Base memory size of
128 Kbytes
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Table 11-9. DRAM Addressing for 32-Bit Wide Memories
MCF5307 Address
Pin
MCF5307 Address Bit
Driven for RAS
MCF5307 Address Bit Driven
when CAS is Asserted
15
15
2
14
14
3
13
13
4
12
12
5
11
11
6
10
10
7
9
9
8
17
17
16
19
19
18
1 Mbyte
21
21
20
4 Mbytes
23
23
22
16 Mbytes
25
25
24
64 Mbytes
Memory Size
Base Memory Size of
64 Kbytes
256 Kbytes
11.3.3.1 Non-Page-Mode Operation
In non-page mode, the simplest mode, the DRAM controller provides termination and runs
a separate bus cycle for each data transfer. Figure 11-5 shows a non-page-mode access in
which a DRAM read is followed by a write. Addresses for a new bus cycle are driven at the
rising clock edge.
For a DRAM block hit, the associated RAS is driven at the next falling edge. Here
DACRn[RCD] = 0, so the address is multiplexed at the next rising edge to provide the
column address. The required CAS signals are then driven at the next falling edge and
remain asserted for the period programmed in DACRn[CAS]. Here, DACRn[RNCN] = 1,
so it is precharged one clock before CAS is negated. On a read, data is sampled on the last
rising edge of the clock that CAS is valid.
BCLKO
A[31:0]
Row
Column
RAS[1] or [0]
DACRn[RCD] = 0
DACRn[RNCN] = 1
CAS[3:0]
DACRn[CAS] = 01]
DRAMW
D[31:0]
Figure 11-5. Basic Non-Page-Mode Operation RCD = 0, RNCN = 1 (4-4-4-4)
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Figure 11-6 shows a variation of the basic cycle. In this case, RCD is 1, so there are two
clocks between RAS and CAS. Note that the address is multiplexed on the rising clock
immediately before CAS is asserted. Because RNCN = 0, RAS and CAS are negated
together. The next bus cycle is initiated, but because DACRn[RP] requires RAS to be
precharged for two clocks, RAS is delayed for a clock in the bus cycle. Note that this does
not delay the address signals, only RAS.
BCLKO
A[31:0]
Row
Column
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RP = 01
RAS[1] or [0]
RCD = 1
CAS[3:0]
RNCN = 0
CAS = 01
DRAMW
D[31:0]
Figure 11-6. Basic Non-Page-Mode Operation RCD = 1, RNCN = 0 (5-5-5-5)
11.3.3.2 Burst Page-Mode Operation
Burst page-mode operation (DACRn[PM] = 01) optimizes memory accesses in page mode
by allowing a row address to remain registered in the DRAM while accessing data in
different columns. This eliminates the setup and hold times associated with the need to
precharge and assert RAS. Therefore, only the first bus cycle in the page takes the full
access time; subsequent accesses are streamlined. Single accesses look the same as
non-page-mode accesses.
Burst page-mode accesses of any size—byte, word, longword, or line—are assumed to
reside in the same page. In this mode, the DRAM controller generates a burst transfer only
when the operand is larger than the DRAM block port size (such as, a line transfer to a
32-bit port or a longword transfer to an 8-bit port). The primary cycle asserts RAS and
CAS; subsequent cycles assert only CAS. At the end of the access, RAS is precharged. The
DRAM controller increments addresses between cycles.
Figure 11-7 shows a read access in burst page mode. Four accesses take place, which could
be a 32-bit access to an 8-bit port or a line access to a 32-bit port. Other burst page-mode
operations may be from 2 to 16 accesses long, depending on the access and port sizes. In
those cases, timing is similar with more or fewer accesses.
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BCLKO
A[31:0]
Row
Column
Column
Column
Column
RAS[1] or [0]
RCD = 0
CAS[3:0]
CAS = 01
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DRAMW
D[31:0]
Figure 11-7. Burst Page-Mode Read Operation (4-3-3-3)
Figure 11-8 shows the write operation with the same configuration.
BCLKO
A[31:0]
Row
Column
Column
Column
Column
RAS[1] or [0]
RCD = 0
CAS[3:0]
CAS = 01
DRAMW
D[31:0]
Figure 11-8. Burst Page-Mode Write Operation (4-3-3-3)
11.3.3.3 Continuous Page Mode
Continuous page mode (DACRn[PM] = 11) is a type of page mode that balances
performance, complexity, and size. In typical page-mode implementations, sequential
addresses are checked for multiple hits in a DRAM block. On a hit, RAS remains asserted
and CAS is asserted with the new column address. On a miss, RAS must be precharged
again before the bus cycle begins.
Continuous page mode supports page-mode operation without requiring an address holding
register per memory block and eliminates the delay for a miss-to-precharge RAS for the
upcoming bus cycle. Because the internal MCF5307 address bus is pipelined, addresses for
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the next bus cycle are often available before the current cycle completes. The two addresses
are compared at the end of the cycle to determine if the next address hits the same page. If
so, RAS remains asserted. If not, or if no access is pending, RAS is precharged before the
next bus cycle is active on the external bus. As a result, a page miss suffers no penalty.
Single accesses not followed by a hit in the page look like non-page-mode accesses.
Figure 11-9 shows a write cycle followed by a read cycle in continuous page mode. The
read hits in the same page as the write so RAS is not negated before the second cycle. Note
that the row address does not appear on the pins for a bus cycle that hits in the page. Column
addresses are immediately multiplexed onto the pins. The third bus cycle is a page miss, so
RAS is precharged before the end of the bus cycle and no extra precharge delay is incurred.
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BCLKO
A[31:0]
Row
Column
Column
Page Hit
RAS[1] or [0]
Row
Column
Page Miss
RNCN=1
RCD=0
CAS[3:0]
CAS=01
DRAMW
D[31:0]
Bus Cycle 1
Bus Cycle 2
Bus Cycle 3
Figure 11-9. Continuous Page-Mode Operation
If a write cycle hits in the page, CAS must be delayed by one clock to allow data to become
valid, as shown in Figure 11-10.
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BCLKO
A[31:0]
Row
Column
Column
Page Hit
RAS[1] or [0]
Page Miss
RCD = 0
CAS[3:0]
CAS = 01
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DRAMW
D[31:0]
Bus Cycle 1
Bus Cycle 2
Figure 11-10. Write Hit in Continuous Page Mode
11.3.3.4 Extended Data Out (EDO) Operation
EDO is a variation of page mode that allows the DRAM to continue driving data out of the
device while CAS is precharging. To support EDO DRAMs, the DRAM controller delays
internal termination of the cycle by one clock so data can continue to be captured as CAS
is being precharged. For data to be driven by the DRAMs, RAS is held after CAS is
negated. EDO operation does not affect write operations. EDO DRAMs can be used in
continuous page or burst page modes. Single accesses not followed by a hit in the page look
like non-page-mode accesses.
Figure 11-11 shows four consecutive EDO accesses. Note that data is sampled after CAS
is negated and that on the last page access, CAS is held until after data is sampled to assure
that the data is driven. This allows RAS to be precharged before the end of the cycle.
BCLKO
A[31:0]
RAS[1] or [0]
RCD = 0
CAS[3:0]
CAS = 00
DRAMW
D[31:0]
Figure 11-11. EDO Read Operation (3-2-2-2)
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11.3.3.5 Refresh Operation
The DRAM controller supports CAS-before-RAS refresh operations that are not
synchronized to bus activity. A special DRAMW pin is provided so refresh can occur
regardless of the state of the processor bus.
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When the refresh counter rolls over, it sets an internal flag to indicate that a refresh is
pending. If that happens during a continuous page-mode access, the page is closed (RAS
precharged) when the data transfer completes to allow the refresh to occur. The flag is
cleared when the refresh cycle is run. Both memory blocks are simultaneously refreshed as
determined by the DCR. DRAM accesses are delayed during refresh. Only an active bus
access to a DRAM block can delay refresh.
Figure 11-12 shows a bus cycle delayed by a refresh operation. Notice that DRAMW is
forced high during refresh. The row address is held until the pending DRAM access.
BCLKO
A[31:0]
RAS[1] or [0]
RRA = 01
RRP = 01
CAS[3:0]
DRAMW
Refresh
Access
Figure 11-12. DRAM Access Delayed by Refresh
11.4 Synchronous Operation
By running synchronously with the system clock instead of responding to asynchronous
control signals, SDRAM can (after an initial latency period) be accessed on every clock;
5-1-1-1 is a typical MCF5307 burst rate to SDRAM.
Note that because the MCF5307 cannot have more than one page open at a time, it does not
support interleaving.
SDRAM controllers are more sophisticated than asynchronous DRAM controllers. Not
only must they manage addresses and data, but they must send special commands for such
functions as precharge, read, write, burst, auto-refresh, and various combinations of these
functions. Table 11-10 lists common SDRAM commands.
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Table 11-10. SDRAM Commands
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Command
Definition
ACTV
Activate. Executed before READ or WRITE executes; SDRAM registers and decodes row address.
MRS
Mode register set.
NOP
No-op. Does not affect SDRAM state machine; DRAM controller control signals negated; RAS asserted.
PALL
Precharge all. Precharges all internal banks of an SDRAM component; executed before new page is
opened.
READ
Read access. SDRAM registers column address and decodes that a read access is occurring.
REF
Refresh. Refreshes internal bank rows of an SDRAM component.
SELF
Self refresh. Refreshes internal bank rows of an SDRAM component when it is in low-power mode.
SELFX
Exit self refresh. This command is sent to the DRAM controller when DCR[IS] is cleared.
WRITE
Write access. SDRAM registers column address and decodes that a write access is occurring.
SDRAMs operate differently than asynchronous DRAMs, particularly in the use of data
pipelines and commands to initiate special actions. Commands are issued to memory using
specific encodings on address and control pins. Soon after system reset, a command must
be sent to the SDRAM mode register to configure SDRAM operating parameters. Note that,
after synchronous operation is selected by setting DCR[SO], DRAM controller registers
reflect the synchronous operation and there is no way to return to asynchronous operation
without resetting the processor.
11.4.1 DRAM Controller Signals in Synchronous Mode
Table 11-11 shows the behavior of DRAM signals in synchronous mode.
Table 11-11. Synchronous DRAM Signal Connections
Signal
Description
SRAS
Synchronous row address strobe. Indicates a valid SDRAM row address is present and can be latched
by the SDRAM. SRAS should be connected to the corresponding SDRAM SRAS. Do not confuse SRAS
with the DRAM controller’s RAS[1:0], which should not be interfaced to the SDRAM SRAS signals.
SCAS
Synchronous column address strobe. Indicates a valid column address is present and can be latched by
the SDRAM. SCAS should be connected to the corresponding signal labeled SCAS on the SDRAM. Do
not confuse SCAS with the DRAM controller’s CAS[3:0] signals.
DRAMW
DRAM read/write. Asserted for write operations and negated for read operations.
RAS[1:0]
Row address strobe. Select each memory block of SDRAMs connected to the MCF5307. One RAS
signal selects one SDRAM block and connects to the corresponding CS signals.
SCKE
Synchronous DRAM clock enable. Connected directly to the CKE (clock enable) signal of SDRAMs.
Enables and disables the clock internal to SDRAM. When CKE is low, memory can enter a power-down
mode where operations are suspended or they can enter self-refresh mode. SCKE functionality is
controlled by DCR[COC]. For designs using external multiplexing, setting COC allows SCKE to provide
command-bit functionality.
CAS[3:0]
Column address strobe. For synchronous operation, CAS[3:0] function as byte enables to the SDRAMs.
They connect to the DQM signals (or mask qualifiers) of the SDRAMs.
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Table 11-11. Synchronous DRAM Signal Connections (Continued)
Signal
BCLKO
Description
Bus clock output. Connects to the CLK input of SDRAMs.
EDGESEL Synchronous edge select. Provides additional output hold time for signals that interface to external
SDRAMs. EDGESEL supports the three following modes for SDRAM interface signals:
• Tied high. Signals change on the rising edge of BCLKO.
• Tied low. Signals change on the falling edge of BCLKO.
• Tied to buffered BCLKO. Signals change on the rising edge of the buffered clock.
EDGESEL can provide additional output hold time for SDRAM interface signals, however the SDRAM
clock and BCLKO frequencies must be the same. See Section 11.4.2, “Using Edge Select (EDGESEL).”
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Figure 11-13 shows a typical signal configuration for synchronous mode.
MCF5307
A[31:0]
D[31:0]
CAS
DRAMW
SCAS
SRAS
SCKE
SDRAM
ADDRESS
DATA
DQM
WE
CAS
RAS
CKE
1
EDGESEL
CLK
BCLKO
1 Trace
length from buffer to CLK must equal length from buffer to EDGESEL.
Figure 11-13. MCF5307 SDRAM Interface
11.4.2 Using Edge Select (EDGESEL)
EDGESEL can ease system-level timings (note that the optional buffer in Figure 11-13 is
for memories that need extra delay). The clock at the input to the SDRAM is monitored and
data is held until the next edge of the bus clock, adding required output hold time to the
address, data, and control signals.
To generate SDRAM interface timing, address, data, and control signals are clocked
through a two-stage shift register. The first stage is clocked on the rising edge of BCLKO;
the second is clocked on the falling edge. This makes the signal available for up to an
additional half bus clock cycle, of which only a small amount is needed for proper timing.
Using the connection shown in Figure 11-13 ensures that data remains held for a longer
time after the rising edge of the SDRAM clock input. This helps to match the MCF5307
output timing with the SDRAM clock.
Figure 11-14 shows the output wave forms for the interface signals changing on the rising
edge (A) and falling edge (B) of BCLKO as determined by whether EDGESEL is tied high
or low. It also shows timing (C) with EDGESEL tied to buffered BCLKO.
11-18
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Synchronous Operation
BCLKO
BCLKO
Address/
Data
VALID
VALID
VALID
Address/
Data
VALID
A: Address and Data Timing with EDGESEL Tied High
VALID
VALID
VALID
B: Address and Data Timing with EDGESEL Tied Low
Buffer Delay
BCLKO
Buffered
Freescale Semiconductor, Inc...
BCLKO
Address/
Data
VALID
VALID
VALID
VALID
C: Address and Data Timing with EDGESEL Tied to Buffered Clock
Figure 11-14. Using EDGESEL to Change Signal Timing
11.4.3 Synchronous Register Set
The memory map in Table 11-1 is the same for both synchronous and asynchronous
operation. However, some bits are different, as noted in the following sections.
11.4.3.1 DRAM Control Register (DCR) in Synchronous Mode
The DRAM control register (DCR), Figure 11-15, controls refresh logic.
15
14
Field
SO
—
Reset
0
13
12
NAM COC
11
10
IS
9
8
7
6
RTIM
5
4
3
2
1
0
RC
Uninitialized
R/W
R/W
Addr
MBAR + 0x100
Figure 11-15. DRAM Control Register (DCR) (Synchronous Mode)
Table 11-12 describes DCR fields.
Table 11-12. DCR Field Descriptions (Synchronous Mode)
Bits
Name
Description
15
SO
Synchronous operation. Selects synchronous or asynchronous mode. When in synchronous mode,
the DRAM controller can be switched to ADRAM mode only by resetting the MCF5307.
0 Asynchronous DRAMs. Default at reset.
1 Synchronous DRAMs
14
—
Reserved, should be cleared.
13
NAM
No address multiplexing. Some implementations require external multiplexing. For example, when
linear addressing is required, the DRAM should not multiplex addresses on DRAM accesses.
0 The DRAM controller multiplexes the external address bus to provide column addresses.
1 The DRAM controller does not multiplex the external address bus to provide column addresses.
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Table 11-12. DCR Field Descriptions (Synchronous Mode) (Continued)
Bits
Name
Description
12
COC
Command on SDRAM clock enable (SCKE). Implementations that use external multiplexing
(NAM = 1) must support command information to be multiplexed onto the SDRAM address bus.
0 SCKE functions as a clock enable; self-refresh is initiated by the DRAM controller through DCR[IS].
1 SCKE drives command information. Because SCKE is not a clock enable, self-refresh cannot be
used (setting DCR[IS]). Thus, external logic must be used if this functionality is desired. External
multiplexing is also responsible for putting the command information on the proper address bit.
11
IS
Initiate self-refresh command.
0 Take no action or issue a SELFX command to exit self refresh.
1 If DCR[COC] = 0, the DRAM controller sends a SELF command to both SDRAM blocks to put them
in low-power, self-refresh state where they remain until IS is cleared, at which point the controller
sends a SELFX command for the SDRAMs to exit self-refresh. The refresh counter is suspended
while the SDRAMs are in self-refresh; the SDRAM controls the refresh period.
10–9
RTIM
Refresh timing. Determines the timing operation of auto-refresh in the DRAM controller. Specifically,
it determines the number of clocks inserted between a REF command and the next possible ACTV
command. This same timing is used for both memory blocks controlled by the DRAM controller. This
corresponds to tRC in the SDRAM specifications.
00 3 clocks
01 6 clocks
1x 9 clocks
8–0
RC
Refresh count. Controls refresh frequency. The number of bus clocks between refresh cycles is
(RC + 1) * 16. Refresh can range from 16–8192 bus clocks to accommodate both standard and
low-power DRAMs with bus clock operation from less than 2 MHz to greater than 50 MHz.
The following example calculates RC for an auto-refresh period for 4096 rows to receive 64 mS of
refresh every 15.625 µs for each row (625 bus clocks at 40 MHz). This operation is the same as in
asynchronous mode.
# of bus clocks = 625 = (RC field + 1) * 16
RC = (625 bus clocks/16) -1 = 38.06, which rounds to 38; therefore, RC = 0x26.
11.4.3.2 DRAM Address and Control Registers (DACR0/DACR1) in
Synchronous Mode
The DRAM address and control registers (DACR0 and DACR1), shown in Figure 11-16,
contain the base address compare value and the control bits for both memory blocks 0 and
1 of the DRAM controller. Address and timing are also controlled by bits in DACRn.
31
Field
Reset
18
BA
17
16
—
Uninitialized
15
14
13
RE
—
CASL —
0
12
11
10
9
8
CBM
Uninitialized
R/W
R/W
Addr
MBAR+0x108 (DACR0); 0x110(DACR1)
7
6
— IMRS
0
5
4
PS
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2
1 0
IP PM —
Uninitialized
Figure 11-16. DACR0 and DACR1 Registers (Synchronous Mode)
11-20
3
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Synchronous Operation
Table 11-13 describes DACRn fields.
Freescale Semiconductor, Inc...
Table 11-13. DACR0/DACR1 Field Descriptions (Synchronous Mode)
Bit
Name
31–18
BA
Base address register. With DCMR[BAM], determines the address range in which the associated
DRAM block is located. Each BA bit is compared with the corresponding address of the current bus
cycle. If all unmasked bits match, the address hits in the associated DRAM block. BA functions the
same as in asynchronous operation.
17–16
—
Reserved, should be cleared.
15
RE
Refresh enable. Determines when the DRAM controller generates a refresh cycle to the DRAM
block.
0 Do not refresh associated DRAM block
1 Refresh associated DRAM block
14
—
Reserved, should be cleared.
13–12
Description
CASL CAS latency. Affects the following SDRAM timing specifications. Timing nomenclature varies with
manufacturers. Refer to the SDRAM specification for the appropriate timing nomenclature:
Number of Bus Clocks
Parameter
CASL= 00 CASL = 01 CASL= 10 CASL= 11
11
10–8
7
—
CBM
—
tRCD—SRAS assertion to SCAS assertion
1
2
3
3
tCASL—SCAS assertion to data out
1
2
3
3
tRAS—ACTV command to precharge command
2
4
6
6
tRP—Precharge command to ACTV command
1
2
3
3
tRWL,tRDL—Last data input to precharge
command
1
1
1
1
tEP—Last data out to precharge command)
1
1
1
1
Reserved, should be cleared.
Command and bank MUX [2:0]. Because different SDRAM configurations cause the command and
bank select lines to correspond to different addresses, these resources are programmable. CBM
determines the addresses onto which these functions are multiplexed.
CBM Command Bit
Bank Select Bits
000
17
18 and up
001
18
19 and up
010
19
20 and up
011
20
21 and up
100
21
22 and up
101
22
23 and up
110
23
24 and up
111
24
25 and up
This encoding and the address multiplexing scheme handle common SDRAM organizations. Bank
select bits include a base bit and all address bits above for SDRAMs with multiple bank select bits.
Reserved, should be cleared.
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Table 11-13. DACR0/DACR1 Field Descriptions (Synchronous Mode) (Continued)
Bit
Name
Description
IMRS
Initiate mode register set (MRS) command. Setting IMRS generates a MRS command to the
associated SDRAMs. In initialization, IMRS should be set only after all DRAM controller registers are
initialized and PALL and REFRESH commands have been issued. After IMRS is set, the next access to
an SDRAM block programs the SDRAM’s mode register. Thus, the address of the access should be
programmed to place the correct mode information on the SDRAM address pins. Because the
SDRAM does not register this information, it doesn’t matter if the IMRS access is a read or a write or
what, if any, data is put onto the data bus. The DRAM controller clears IMRS after the MRS command
finishes.
0 Take no action
1 Initiate MRS command
5–4
PS
Port size. Indicates the port size of the associated block of SDRAM, which allows for dynamic sizing
of associated SDRAM accesses. PS functions the same in asynchronous operation.
00 32-bit port
01 8-bit port
1x 16-bit port
3
IP
Initiate precharge all (PALL) command. The DRAM controller clears IP after the PALL command is
finished. Accesses via IP should be no wider than the port size programmed in PS.
0 Take no action.
1 A PALL command is sent to the associated SDRAM block. During initialization, this command is
executed after all DRAM controller registers are programmed. After IP is set, the next write to an
appropriate SDRAM address generates the PALL command to the SDRAM block.
2
PM
Page mode. Indicates how the associated SDRAM block supports page-mode operation.
0 Page mode on bursts only. The DRAM controller dynamically bursts the transfer if it falls within a
single page and the transfer size exceeds the port size of the SDRAM block. After the burst, the
page closes and a precharge is issued.
1 Continuous page mode. The page stays open and only SCAS needs to be asserted for sequential
SDRAM accesses that hit in the same page, regardless of whether the access is a burst.
1–0
—
Reserved, should be cleared.
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11.4.3.3 DRAM Controller Mask Registers (DMR0/DMR1)
The DMRn, Figure 11-17, include mask bits for the base address and for address attributes.
They are the same as in asynchronous operation.
31
Field
18 17
BAM
9
—
Reset
8
7
6
5
4
3
Uninitialized
R/W
R/W
Addr
MBAR + 0x10C (DMR0), 0x114 (DMR1)
Figure 11-17. DRAM Controller Mask Registers (DMR0 and DMR1)
Table 11-14 describes DMRn fields.
11-22
2
1
0
WP — C/I AM SC SD UC UD V
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Table 11-14. DMR0/DMR1 Field Descriptions
Bits
Name
Description
31–18
BAM
Base address mask. Masks the associated DACRn[BA]. Lets the DRAM controller connect to various
DRAM sizes. Mask bits need not be contiguous (see Section 11.5, “SDRAM Example.”)
0 The associated address bit is used in decoding the DRAM hit to a memory block.
1 The associated address bit is not used in the DRAM hit decode.
17–9
—
8
WP
7
—
6–1
AMx
Reserved, should be cleared.
Write protect. Determines whether the associated block of DRAM is write protected.
0 Allow write accesses
1 Ignore write accesses. The DRAM controller ignores write accesses to the memory block and an
address exception occurs. Write accesses to a write-protected DRAM region are compared in the
chip select module for a hit. If no hit occurs, an external bus cycle is generated. If this external bus
cycle is not acknowledged, an access exception occurs.
Reserved, should be cleared.
Address modifier masks. Determine which accesses can occur in a given DRAM block.
0 Allow access type to hit in DRAM
1 Do not allow access type to hit in DRAM
Bit
C/I
0
V
Associated Access Type
CPU space/interrupt acknowledge
Access Definition
MOVEC instruction or interrupt acknowledge cycle
AM
Alternate master
External or DMA master
SC
Supervisor code
Any supervisor-only instruction access
SD
Supervisor data
Any data fetched during the instruction access
UC
User code
Any user instruction
UD
User data
Any user data
Valid. Cleared at reset to ensure that the DRAM block is not erroneously decoded.
0 Do not decode DRAM accesses.
1 Registers controlling the DRAM block are initialized; DRAM accesses can be decoded.
11.4.4 General Synchronous Operation Guidelines
To reduce system logic and to support a variety of SDRAM sizes, the DRAM controller
provides SDRAM control signals as well as a multiplexed row address and column address
to the SDRAM.
When SDRAM blocks are accessed, the DRAM controller can operate in either burst or
continuous page mode. The following sections describe the DRAM controller interface to
SDRAM, the supported bus transfers, and initialization.
11.4.4.1 Address Multiplexing
Table 11-6 shows the generic address multiplexing scheme for SDRAM configurations. All
possible address connection configurations can be derived from this table.
The following tables provide a more comprehensive, step-by-step way to determine the
correct address line connections for interfacing the MCF5307 to SDRAM. To use the
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tables, find the one that corresponds to the number of column address lines on the SDRAM
and to the port size as seen by the MCF5307, which is not necessarily the SDRAM port
size. For example, if two 1M x 16-bit SDRAMs together form a 2M x 32-bit memory, the
port size is 32 bits. Most SDRAMs likely have fewer address lines than are shown in the
tables, so follow only the connections shown until all SDRAM address lines are connected.
Table 11-15. MCF5307 to SDRAM Interface (8-Bit Port, 9-Column Address Lines)
Freescale Semiconductor, Inc...
MCF5307 A17 A16 A15 A14 A13 A12 A11 A10 A9 A18 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
17
16
15
14
13
12
11
10
9
Column
0
1
2
3
4
5
6
7
8
SDRAM
Pins
18
19
20
21
22
23
24
25
26
27
28
29
30
31
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21 A22
Table 11-16. MCF5307 to SDRAM Interface (8-Bit Port,10-Column Address Lines)
MCF5307 A17 A16 A15 A14 A13 A12 A11 A10 A9 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
17
16
15
14
13
12
11
10
9
19
Column
0
1
2
3
4
5
6
7
8
18
SDRAM
Pins
20
21
22
23
24
25
26
27
28
29
30
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21
Table 11-17. MCF5307 to SDRAM Interface (8-Bit Port,11-Column Address
Lines)
MCF5307 A17 A16 A15 A14 A13 A12 A11 A10 A9 A19 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
17
16
15
14
13
12
11
10
9
19
21
Column
0
1
2
3
4
5
6
7
8
18
20
SDRAM
Pins
22
23
24
25
26
27
28
29
30
31
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20
Table 11-18. MCF5307 to SDRAM Interface (8-Bit Port,12-Column Address Lines)
MCF5307 A17 A16 A15 A14 A13 A12 A11 A10 A9 A19 A21 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
17
16
15
14
13
12
11
10
9
19
21
23
Column
0
1
2
3
4
5
6
7
8
18
20
22
SDRAM
Pins
11-24
31
24
25
26
27
28
29
30
31
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19
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Table 11-19. MCF5307 to SDRAM Interface (8-Bit Port,13-Column Address
Lines)
MCF5307 A17 A16 A15 A14 A13 A12 A11 A10 A9 A19 A21 A23 A25 A26 A27 A28 A29 A30 A31
Pins
Row
Column
SDRAM
Pins
17
16
15
14
13
12
11
10
9
19
21
23
25
0
1
2
3
4
5
6
7
8
18
20
22
24
26
27
28
29
30
31
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18
Table 11-20. MCF5307 to SDRAM Interface (16-Bit Port, 8-Column Address Lines)
Freescale Semiconductor, Inc...
MCF5307 A16 A15 A14 A13 A12 A11 A10 A9 A17 A18 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
16
15
14
13
12
11
10
9
Column
1
2
3
4
5
6
7
8
SDRAM
Pins
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21 A22
Table 11-21. MCF5307 to SDRAM Interface (16-Bit Port, 9-Column Address Lines)
MCF5307 A16 A15 A14 A13 A12 A11 A10 A9 A18 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
16
15
14
13
12
11
10
9
18
Column
1
2
3
4
5
6
7
8
17
SDRAM
Pins
19
20
21
22
23
24
25
26
27
28
29
30
31
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21
Table 11-22. MCF5307 to SDRAM Interface (16-Bit Port, 10-Column Address Lines)
MCF5307 A16 A15 A14 A13 A12 A11 A10 A9 A18 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
16
15
14
13
12
11
10
9
18
20
21
22
23
24
25
26
27
28
29
30
31
Column
1
2
3
4
5
6
7
8
17
19
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20
Table 11-23. MCF5307 to SDRAM Interface (16-Bit Port, 11-Column Address Lines)
MCF5307 A16 A15 A14 A13 A12 A11 A10 A9 A18 A20 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
16
15
14
13
12
11
10
9
18
20
22
Column
1
2
3
4
5
6
7
8
17
19
21
23
24
25
26
27
28
29
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19
Chapter 11. Synchronous/Asynchronous DRAM Controller Module
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31
11-25
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Synchronous Operation
Table 11-24. MCF5307 to SDRAM Interface (16-Bit Port, 12-Column Address Lines)
MCF5307
A16 A15 A14 A13 A12 A11 A10
Pins
A9
A18 A20 A22 A24 A25 A26 A27 A28 A29 A30 A31
Row
16
15
14
13
12
11
10
9
18
20
22
24
Column
1
2
3
4
5
6
7
8
17
19
21
23
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
25
26
27
28
29
30
31
A10 A11 A12 A13 A14 A15 A16 A17 A18
Table 11-25. MCF5307to SDRAM Interface (16-Bit Port, 13-Column-Address Lines)
Freescale Semiconductor, Inc...
MCF5307 A16 A15 A14 A13 A12 A11 A10
Pins
Row
16
15
14
13
12
11
A9
10
A18 A20 A22 A24 A26 A27 A28 A29 A30 A31
9
18
20
Column
1
2
3
4
5
6
7
8
17
19
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
22
24
26
21
23
25
27
28
29
30
31
A10 A11 A12 A13 A14 A15 A16 A17
Table 11-26. MCF5307 to SDRAM Interface (32-Bit Port, 8-Column Address Lines)
MCF5307 A15 A14 A13 A12 A11 A10 A9 A17 A18 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
15
14
13
12
11
10
9
17
Column
2
3
4
5
6
7
8
16
SDRAM
Pins
18
19
20
21
22
23
24
25
26
27
28
29
30
31
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20 A21
Table 11-27. MCF5307 to SDRAM Interface (32-Bit Port, 9-Column Address Lines)
MCF5307 A15 A14 A13 A12 A11 A10 A9 A17 A19 A20 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
15
14
13
12
11
10
9
17
19
Column
2
3
4
5
6
7
8
16
18
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
20
21
22
23
24
25
26
27
28
29
30
31
A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20
Table 11-28. MCF5307 to SDRAM Interface (32-Bit Port, 10-Column Address Lines)
MCF5307 A15 A14 A13 A12 A11 A10 A9 A17 A19 A21 A22 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
15
14
13
12
11
10
9
17
19
21
22
23
24
25
26
27
28
29
30
31
Column
2
3
4
5
6
7
8
16
18
20
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19
11-26
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Table 11-29. MCF5307 to SDRAM Interface (32-Bit Port, 11-Column Address Lines)
MCF5307 A15 A14 A13 A12 A11 A10 A9 A17 A19 A21 A23 A24 A25 A26 A27 A28 A29 A30 A31
Pins
Row
15
14
13
12
11
10
9
17
19
21
23
Column
2
3
4
5
6
7
8
16
18
20
22
24
25
26
27
28
29
30
31
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9 A10 A11 A12 A13 A14 A15 A16 A17 A18
Table 11-30. MCF5307 to SDRAM Interface (32-Bit Port, 12-Column Address Lines)
Freescale Semiconductor, Inc...
MCF5307 A15 A14 A13 A12 A11 A10
Pins
A9
A17 A19 A21 A23 A25 A26 A27 A28 A29 A30 A31
Row
15
14
13
12
11
10
9
17
19
21
23
25
Column
2
3
4
5
6
7
8
16
18
20
22
24
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
26
27
28
29
30
31
A10 A11 A12 A13 A14 A15 A16 A17
11.4.4.2 Interfacing Example
The tables in the previous section can be used to configure the interface in the following
example. To interface one 2M x 32-bit x 4 bank SDRAM component (8 columns) to the
MCF5307, the connections would be as shown in Table 11-31.
Table 11-31. SDRAM Hardware Connections
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10 = CMD
BA0
BA1
MCF5307
Pins
A15
A14
A13
A12
A11
A10
A9
A17
A18
A19
A20
A21
A22
11.4.4.3 Burst Page Mode
SDRAM can efficiently provide data when an SDRAM page is opened. As soon as SCAS
is issued, the SDRAM accepts a new address and asserts SCAS every clock for as long as
accesses are in that page. In burst page mode, there are multiple read or write operations for
every ACTV command in the SDRAM if the requested transfer size exceeds the port size of
the associated SDRAM. The primary cycle of the transfer generates the ACTV and READ or
WRITE commands; secondary cycles generate only READ or WRITE commands. As soon as
the transfer completes, the PALL command is generated to prepare for the next access.
Note that in synchronous operation, burst mode and address incrementing during burst
cycles are controlled by the MCF5307 DRAM controller. Thus, instead of the SDRAM
enabling its internal burst incrementing capability, the MCF5307 controls this function.
This means that the burst function that is enabled in the mode register of SDRAMs must be
disabled when interfacing to the MCF5307.
Figure 11-18 shows a burst read operation. In this example, DACR[CASL] = 01, for an
SRAS-to-SCAS delay (tRCD) of 2 BCLKO cycles. Because tRCD is equal to the read CAS
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Synchronous Operation
Freescale Semiconductor, Inc.
latency (SCAS assertion to data out), this value is also 2 BCLKO cycles. Notice that NOPs
are executed until the last data is read. A PALL command is executed one cycle after the last
data transfer.
BCLKO
A[31:0]
Row
Column
Column Column
Column
SRAS
tRCD = 2
Freescale Semiconductor, Inc...
SCAS
tEP
DRAMW
tCASL = 2
D[31:0]
RAS[0] or [1]
CAS[3:0]
ACTV
NOP
READ
NOP
NOP
PALL
Figure 11-18. Burst Read SDRAM Access
Figure 11-19 shows the burst write operation. In this example, DACR[CASL] = 01, which
creates an SRAS-to-SCAS delay (tRCD) of 2 BCLKO cycles. Note that data is available
upon SCAS assertion and a burst write cycle completes two cycles sooner than a burst read
cycle with the same tRCD. The next bus cycle is initiated sooner, but cannot begin an
SDRAM cycle until the precharge-to-ACTV delay completes.
11-28
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Synchronous Operation
BCLKO
A[31:0]
Row
Column
Column
Column
Column
SRAS
tRP
SCAS
tCASL = 2
tRWL
Freescale Semiconductor, Inc...
DRAMW
D[31:0]
RAS[0] or [1]
CAS[3:0]
ACTV
NOP
WRITE
NOP
PALL
Figure 11-19. Burst Write SDRAM Access
Accesses in synchronous burst page mode always cause the following sequence:
1.
2.
3.
4.
5.
6.
command
NOP commands to assure SRAS-to-SCAS delay (if CAS latency is 1, there are no
NOP commands).
Required number of READ or WRITE commands to service the transfer size with the
given port size.
Some transfers need more NOP commands to assure the ACTV-to-precharge delay.
PALL command
Required number of idle clocks inserted to assure precharge-to-ACTV delay.
ACTV
11.4.4.4 Continuous Page Mode
Continuous page mode is identical to burst page mode, except that it allows the processor
core to handle successive bus cycles that hit the same page without having to close the page.
When the current bus cycle finishes, the MCF5307 core internal pipelined bus can predict
whether the upcoming cycle will hit in the same page.
•
•
If the next bus cycle is not pending or misses in the page, the PALL command is
generated to the SDRAM.
If the next bus cycle is pending and hits in the page, the page is left open, and the
next SDRAM access begins with a READ or WRITE command.
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11-29
Synchronous Operation
•
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Because of the nature of the internal CPU pipeline this condition does not occur
often; however, the use of continuous page mode is recommended because it can
provide a slight performance increase.
Figure 11-20 shows two read accesses in continuous page mode. Note that there is no
precharge between the two accesses. Also notice that the second cycle begins with a read
operation with no ACTV command.
BCLKO
Row
Freescale Semiconductor, Inc...
A[31:0]
Column
Column
SRAS
SCAS
tEP
tRCD = 2
DRAMW
tCASL = 2
tCASL = 2
D[31:0]
RAS[0] or [1]
CAS[3:0]
ACTV
NOP
READ
NOP
READ
NOP
NOP
PALL
Figure 11-20. Synchronous, Continuous Page-Mode Access—Consecutive Reads
Figure 11-21 shows a write followed by a read in continuous page mode. Because the bus
cycle is terminated with a WRITE command, the second cycle begins sooner after the write
than after the read. A read requires data to be returned before the bus cycle can terminate.
Note that in continuous page mode, secondary accesses output the column address only.
11-30
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Synchronous Operation
BCLKO
Row
A[31:0]
Column
Column
SRAS
SCAS
tEP
tRCD = 3
Freescale Semiconductor, Inc...
DRAMW
tCASL = 3
D[31:0]
RAS[0] or [1]
CAS[3:0]
ACTV
NOP
WRITE
NOP
READ
NOP
NOP
NOP
PALL
Figure 11-21. Synchronous, Continuous Page-Mode Access—Read after Write
11.4.4.5 Auto-Refresh Operation
The DRAM controller is equipped with a refresh counter and control. This logic is
responsible for providing timing and control to refresh the SDRAM. Once the refresh
counter is set, and refresh is enabled, the counter counts to zero. At this time, an internal
refresh request flag is set and the counter begins counting down again. The DRAM
controller completes any active burst operation and then performs a PALL operation. The
DRAM controller then initiates a refresh cycle and clears the refresh request flag. This
refresh cycle includes a delay from any precharge to the auto-refresh command, the
auto-refresh command, and then a delay until any ACTV command is allowed. Any SDRAM
access initiated during the auto-refresh cycle is delayed until the cycle is completed.
Figure 11-22 shows the auto-refresh timing. In this case, there is an SDRAM access when
the refresh request becomes active. The request is delayed by the precharge to ACTV delay
programmed into the active SDRAM bank by the CAS bits. The REF command is then
generated and the delay required by DCR[RTIM] is inserted before the next ACTV
command is generated. In this example, the next bus cycle is initiated, but does not generate
an SDRAM access until TRC is finished. Because both chip selects are active during the REF
command, it is passed to both blocks of external SDRAM.
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Synchronous Operation
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BCLKO
A[31:0]
SRAS
tRC = 6
tRCD = 2
SCAS
Freescale Semiconductor, Inc...
DRAMW
RAS[0] or [1]
PALL
NOP
REF
NOP
ACTV
Figure 11-22. Auto-Refresh Operation
11.4.4.6 Self-Refresh Operation
Self-refresh is a method of allowing the SDRAM to enter into a low-power state, while at
the same time to perform an internal refresh operation and to maintain the integrity of the
data stored in the SDRAM. The DRAM controller supports self-refresh with DCR[IS].
When IS is set, the SELF command is sent to the SDRAM. When IS is cleared, the SELFX
command is sent to the DRAM controller. Figure 11-23 shows the self-refresh operation.
BCLKO
SRAS
tRCD = 2
SCAS
tRC = 6
DRAMW
RAS[0] or [1]
SCKE
(DCR[COC] = 0)
PALL
NOP
SELF
SelfRefresh
Active
SELFX
NOP
Figure 11-23. Self-Refresh Operation
11-32
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First
Possible
ACTV
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Synchronous Operation
11.4.5 Initialization Sequence
Synchronous DRAMs have a prescribed initialization sequence. The DRAM controller
supports this sequence with the following procedure:
Freescale Semiconductor, Inc...
1. SDRAM control signals are reset to idle state. Wait the prescribed period after reset
before any action is taken on the SDRAMs. This is normally around 100 µs.
2. Initialize the DCR, DACR, and DMR in their operational configuration. Do not yet
enable PALL or REF commands.
3. Issue a PALL command to the SDRAMs by setting DCR[IP] and accessing a
SDRAM location. Wait the time (determined by tRP) before any other execution.
4. Enable refresh (set DACR[RE]) and wait for at least 8 refreshes to occur.
5. Before issuing the MRS command, determine if the DMR mask bits need to be
modified to allow the MRS to execute properly
6. Issue the MRS command by setting DACR[IMRS] and accessing a location in the
SDRAM. Note that mode register settings are driven on the SDRAM address bus, so
care must be taken to change DMR[BAM] if the mode register configuration does
not fall in the address range determined by the address mask bits. After the mode
register is set, DMR mask bits can be restored to their desired configuration.
11.4.5.1 Mode Register Settings
It is possible to configure the operation of SDRAMs, namely their burst operation and CAS
latency, through the SDRAM component’s mode register. CAS latency is a function of the
speed of the SDRAM and the bus clock of the DRAM controller. The DRAM controller
operates at a CAS latency of 1, 2, or 3.
Although the MCF5307 DRAM controller supports bursting operations, it does not use the
bursting features of the SDRAMs. Because the MCF5307 can burst operand sizes of 1, 2,
4, or 16 bytes long, the concept of a fixed burst length in the SDRAMs mode register
becomes problematic. Therefore, the MCF5307 DRAM controller generates the burst
cycles rather than the SDRAM device. Because the MCF5307 generates a new address and
a READ or WRITE command for each transfer within the burst, the SDRAM mode register
should be set either to a burst length of one or to not burst. This allows bursting to be
controlled by the MCF5307 instead.
The SDRAM mode register is written by setting the associated block’s DACR[IMRS].
First, the base address and mask registers must be set to the appropriate configuration to
allow the mode register to be set. Note that improperly set DMR mask bits may prevent
access to the mode register address. Thus, the user should determine the mapping of the
mode register address to the MCF5307 address bits to find out if an access is blocked. If the
DMR setting prohibits mode register access, the DMR should be reconfigured to enable the
access and then set to its necessary configuration after the MRS command executes.
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SDRAM Example
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The associated CBM bits should also be initialized. After DACR[IMRS] is set, the next
access to the SDRAM address space generates the MRS command to that SDRAM. The
address of the access should be selected to place the correct mode information on the
SDRAM address pins. The address is not multiplexed for the MRS command. The MRS
access can be a read or write. The important thing is that the address output of that access
needs the correct mode programming information on the correct address bits.
Figure 11-24 shows the MRS command, which occurs in the first clock of the bus cycle.
BCLKO
Freescale Semiconductor, Inc...
A[31:0]
SRAS, SCAS
DRAMW
D[31:0]
RAS[1] or [0]
MRS
Figure 11-24. Mode Register Set (MRS) Command
11.5 SDRAM Example
This example interfaces a 2M x 32-bit x 4 bank SDRAM component to a MCF5307
operating at 40 MHz. Table 11-32 lists design specifications for this example.
Table 11-32. SDRAM Example Specifications
Parameter
Speed grade (-8E)
Specification
40 MHz (25-nS period)
10 rows, 8 columns
Two bank-select lines to access four internal banks
ACTV-to-read/write
delay (tRCD)
Period between auto refresh and ACTV command (tRC)
ACTV
command to precharge command (tRAS)
Precharge command to ACTV command (tRP)
11-34
20 nS (min.)
70 nS
48 nS (min.)
20 nS (min.)
Last data input to PALL command (tRWL)
1 bus clock (25 nS)
Auto refresh period for 4096 rows (tREF)
64 mS
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SDRAM Example
11.5.1 SDRAM Interface Configuration
To interface this component to the MCF5307 DRAM controller, use the connection table
that corresponds to a 32-bit port size with 8 columns (Table 11-26). Two pins select one of
four banks when the part is functional. Table 11-33 shows the proper hardware hook-up.
Table 11-33. SDRAM Hardware Connections
MCF5307
Pins
A15
A14
A13
A12
A11
A10
A9
A17
A18
A19
A20
A21
A22
SDRAM
Pins
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10 = CMD
BA0
BA1
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11.5.2 DCR Initialization
At power-up, the DCR has the following configuration if synchronous operation and
SDRAM address multiplexing is desired.
15
Field SO
Setting
1
14
13
res
X
0
(hex)
12
NAM COC
0
11
IS
0
10
9
8
0
RTIM
0
8
0
RC
0
0
0
0
1
0
0
2
1
1
0
6
Figure 11-25. Initialization Values for DCR
This configuration results in a value of 0x8026 for DCR, as shown in Table 11-34.
Table 11-34. DCR Initialization Values
Bits
Name
Setting
Description
15
SO
1
Indicating synchronous operation
14
—
x
Don’t care (reserved)
13
NAM
0
Indicating SDRAM controller multiplexes address lines internally
12
COC
0
SCKE is used as clock enable instead of command bit because user is not multiplexing
address lines externally and requires external command feed.
11
IS
0
At power-up, allowing power self-refresh state is not appropriate because registers are
being set up.
10–9
RTIM
00
Because tRC value is 70 nS, indicating a 3-clock refresh-to-ACTV timing.
8–0
RC
0x26
Specification indicates auto-refresh period for 4096 rows to be 64 mS or refresh every
15.625 µs for each row, or 625 bus clocks at 40 MHz. Because DCR[RC] is incremented by
1 and multiplied by 16, RC = (625 bus clocks/16) -1 = 38.06 = 0x38
11.5.3 DACR Initialization
As shown in Figure 11-26, in this example the SDRAM is programmed to access only the
second 512-Kbyte block of each 1-Mbyte partition in the SDRAM (each 16 Mbytes). The
starting address of the SDRAM is 0xFF80_0000. Continuous page mode feature is used.
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SDRAM Example
Accessible
Memory
SDRAM Component
Bank 0
Bank 1
512 Kbyte
Bank 2
512 Kbyte
1 Mbyte
Bank 3
512 Kbyte
1 Mbyte
512 Kbyte
1 Mbyte
512 Kbyte
1 Mbyte
512 Kbyte
512 Kbyte
512 Kbyte
Figure 11-26. SDRAM Configuration
Freescale Semiconductor, Inc...
The DACRs should be programmed as shown in Figure 11-27.
31
18
Field
Setting
(hex)
Field
Setting
15
14
—
1111_1111_1000_10
xx
0
X
(hex)
15
13
12
11
CASL
—
00
X
0
16
—
15
RE
17
BA
8
10
8
8
7
6
3
2
CBM
—
IMRS
PS
IP
PM
011
X
0
00
0
1
3
5
4
0
1
0
—
xx
4
Figure 11-27. DACR Register Configuration
This configuration results in a value of DACR0 = 0xFF88_0304, as described in
Table 11-35. DACR1 initialization is not needed because there is only one block.
Subsequently, DACR1[RE,IMRS,IP] should be cleared; everything else is a don’t care.
Table 11-35. DACR Initialization Values
Bits
Name
Setting
Description
31–18
BA
Base address. So DACR0[31–16] = 0xFF88, which places the starting address of the
SDRAM accessible memory at 0xFF88_0000.
17–16
—
Reserved. Don’t care.
15
RE
14
—
13–12
11
10–8
CASL
0
00
—
CBM
0, which keeps auto-refresh disabled because registers are being set up at this time.
Reserved. Don’t care.
Indicates a delay of data 1 cycle after CAS is asserted
Reserved. Don’t care.
011
Command bit is pin 20 and bank selects are 21 and up.
7
—
6
IMRS
0
Indicates MRS command has not been initiated.
5–4
PS
00
32-bit port.
3
IP
0
Indicates precharge has not been initiated.
11-36
Reserved. Don’t care.
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SDRAM Example
Table 11-35. DACR Initialization Values
Bits
Name
Setting
2
PM
1
1–0
—
Description
Indicates continuous page mode
Reserved. Don’t care.
11.5.4 DMR Initialization
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In this example, again, only the second 512-Kbyte block of each 1-Mbyte space is accessed
in each bank. In addition the SDRAM component is mapped only to readable and writable
supervisor and user data. The DMRs have the following configuration.
31
Field
Setting
17
1
X
BAM
0
0
0
(hex)
0
0
0
0
0
15
9
X
X
X
(hex)
0
1
X
X
0
X
1
1
0
7
—
X
16
—
0
0
Field
Setting
18
X
4
8
7
6
5
4
3
2
1
0
WP
—
C/I
AM
SC
SD
UC
UD
V
0
X
1
1
1
0
1
0
1
0
7
5
Figure 11-28. DMR0 Register
With this configuration, the DMR0 = 0x0074_0075, as described in Table 11-36.
Table 11-36. DMR0 Initialization Values
Bits
Name
31–16
BAM
15–9
—
Setting
Description
With bits 17 and 16 as don’t cares, BAM = 0x0074, which leaves bank select bits and
upper 512K select bits unmasked. Note that bits 22 and 21 are set because they are used
as bank selects; bit 20 is set because it controls the 1-Mbyte boundary address.
Reserved. Don’t care.
8
WP
7
—
0
Allow reads and writes
6
C/I
5
AM
1
Disable alternate master access
4
SC
1
Disable supervisor code accesses
3
SD
0
Enable supervisor data accesses
2
UC
1
Disable user code accesses
1
UD
0
Enable user data accesses
0
V
1
Enable accesses.
Reserved
1
Disable CPU space access
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SDRAM Example
11.5.5 Mode Register Initialization
When DACR[IMRS] is set, a bus cycle initializes the mode register. If the mode register
setting is read on A[10:0] of the SDRAM on the first bus cycle, the bit settings on the
corresponding MCF5307 address pins must be determined while being aware of masking
requirements.
Table 11-37 lists the desired initialization setting:
Freescale Semiconductor, Inc...
Table 11-37. Mode Register Initialization
MCF5307 Pins
SDRAM Pins
A20
A10
A19
A18
Mode Register Initialization
Reserved
X
A9
WB
0
A8
Opmode
0
A17
A7
Opmode
0
A9
A6
CASL
0
A10
A5
CASL
0
A11
A4
CASL
1
A12
A3
BT
0
A13
A2
BL
0
A14
A1
BL
0
A15
A0
BL
0
Next, this information is mapped to an address to determine the hexadecimal value.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
X
X
X
X
X
X
X
X
X
X
X
X
0
0
0
X
Field
Setting
(hex)
0
15
14
0
13
12
11
10
0
9
8
7
6
0
5
4
3
2
1
Field
Setting
(hex)
0
V
0
0
0
0
0
1
0
0
8
X
X
X
X
X
X
X
0
X
X
0
Figure 11-29. Mode Register Mapping to MCF5307 A[31:0]
Although A[31:20] corresponds to the address programmed in DACR0, according to how
DACR0 and DMR0 are initialized, bit 19 must be set to hit in the SDRAM. Thus, before
the mode register bit is set, DMR0[19] must be set to enable masking.
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SDRAM Example
11.5.6 Initialization Code
The following assembly code initializes the SDRAM example.
Power-Up Sequence:
move.w
move.w
move.l
move.l
move.l
move.l
#0x8026, d0
d0, DCR
#0xFF880300, d0
d0, DACR0
#0x00740075, d0
d0, DMR0
//Initialize DCR
//Initialize DACR0
//Initialize DMR0
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Precharge Sequence:
move.l
move.l
move.l
move.l
#0xFF880308, d0
d0, DACR0
#0xBEADDEED, d0
d0, 0xFF880000
//Set DACR0[IP]
//Write to memory location to init. precharge
Refresh Sequence:
move.l
move.l
#0xFF888300, d0
d0, DACR0
//Enable refresh bit in DACR0
Mode Register Initialization Sequence:
move.l #0x00600075, d0
move.l d0, DMR0
move.l #0xFF888340, d0
move.l d0, DACR0
move.l #0x00000000, d0
register
move.l d0, 0xFF800800
//Mask bit 19 of address
//Enable DACR0[IMRS]; DACR0[RE] remains set
//Access
SDRAM
address
to
initialize
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mode
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SDRAM Example
11-40
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Part III
Peripheral Module
Intended Audience
Part III describes the operation and configuration of the MCF5307 DMA, timer, UART, and
parallel port modules, and describes how they interface with the system integration unit,
described in Part II.
Contents
Part III contains the following chapters:
•
•
•
•
Chapter 12, “DMA Controller Module,” provides an overview of the DMA
controller module and describes in detail its signals and registers. The latter sections
of this chapter describe operations, features, and supported data transfer modes in
detail, showing timing diagrams for various operations.
Chapter 13, “Timer Module,” describes configuration and operation of the two
general-purpose timer modules, timer 0 and timer 1. It includes programming
examples.
Chapter 14, “UART Modules,” describes the use of the universal
asynchronous/synchronous receiver/transmitters (UARTs) implemented on the
MCF5307 and includes programming examples.
Chapter 15, “Parallel Port (General-Purpose I/O),” describes the operation and
programming model of the parallel port pin assignment, direction-control, and data
registers. It includes a code example for setting up the parallel port.
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Acronyms and Abbreviations
Table III-i describes acronyms and abbreviations used in Part III.
Table III-i. Acronyms and Abbreviated Terms
Freescale Semiconductor, Inc...
Term
Meaning
ADC
Analog-to-digital conversion
BIST
Built-in self test
CODEC
Code/decode
DAC
Digital-to-analog conversion
DMA
Direct memory access
DSP
Digital signal processing
EDO
Extended data output (DRAM)
FIFO
First-in, first-out
GPIO
I2C
Inter-integrated circuit
IEEE
Institute for Electrical and Electronics Engineers
IFP
Instruction fetch pipeline
IPL
Interrupt priority level
JEDEC
Joint Electron Device Engineering Council
JTAG
Joint Test Action Group
LIFO
Last-in, first-out
LRU
Least recently used
LSB
Least-significant byte
lsb
Least-significant bit
MAC
Multiple accumulate unit
MBAR
Memory base address register
MSB
Most-significant byte
msb
Most-significant bit
Mux
Multiplex
NOP
No operation
OEP
Operand execution pipeline
PC
Program counter
PCLK
Processor clock
PLL
Phase-locked loop
III-ii
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Table III-i. Acronyms and Abbreviated Terms (Continued)
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Term
Meaning
PLRU
Pseudo least recently used
POR
Power-on reset
PQFP
Plastic quad flat pack
RISC
Reduced instruction set computing
Rx
Receive
SIM
System integration module
SOF
Start of frame
TAP
Test access port
TTL
Transistor-to-transistor logic
Tx
Transmit
UART
Universal asynchronous/synchronous receiver transmitter
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Chapter 12
DMA Controller Module
This chapter describes the MCF5307 DMA controller module. It provides an overview of
the module and describes in detail its signals and registers. The latter sections of this
chapter describe operations, features, and supported data transfer modes in detail.
12.1 Overview
The direct memory access (DMA) controller module provides an efficient way to move
blocks of data with minimal processor interaction. The DMA module, shown in
Figure 12-1, provides four channels that allow byte, word, or longword operand transfers.
Each channel has a dedicated set of registers that define the source and destination
addresses (SARn and DARn), byte count (BCRn), and control and status (DCRn and
DSRn). Transfers can be dual or single address to off-chip devices or dual address to
on-chip devices, such as UART, SDRAM controller, and parallel port.
Channel 0 Channel 1 Channel 2 Channel 3
Internal
Bus
External
Requests
SAR0
SAR1
SAR2
SAR3
DAR0
DAR1
DAR2
DAR3
BCR0
BCR1
BCR2
BCR3
DCR0
DCR1
DCR2
DCR3
DSR0
DSR1
DSR2
DSR3
Channel
Requests
Interrupts
Channel
Attributes
Channel
Enables
External Bus Address
MUX
MUX
Control
External Bus Size
Current Master Attributes
Arbitration/
Control
Data Path
Read Bus Data
Data Path
Control
Write Bus Data
Interface Bus
Registered
Bus Signals
Figure 12-1. DMA Signal Diagram
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DMA Signal Description
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12.1.1 DMA Module Features
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The DMA controller module features are as follows:
•
•
•
•
•
•
•
•
•
•
Four fully independent, programmable DMA controller channels/bus modules
Auto-alignment feature for source or destination accesses
Dual- and single-address transfers
Two external request pins (DREQ[1:0]) provided for channels 1 and 0
Channel arbitration on transfer boundaries
Data transfers in 8-, 16-, 32-, or 128-bit blocks using a 16-byte buffer
Continuous-mode and cycle-steal transfers
Independent transfer widths for source and destination
Independent source and destination address registers
Data transfer can occur in as few as two clocks
12.2 DMA Signal Description
Table 12-1 briefly describes the DMA module signals that provide handshake control for
either a source or destination external device.
Table 12-1. DMA Signals
Signal
I/O
Description
DREQ[1:0]/
PP[6:5]
I
External DMA request. DREQ[1:0] can serve as the DMA request inputs or as two parallel port
bits. They are programmable individually through the PAR. A peripheral device asserts these
inputs to request an operand transfer between it and memory.
DREQ signals are asserted to initiate DMA accesses in the respective channels. The system
should drive unused DREQ signals to logic high. Although each channel has an individual
DREQ signal, in the MCF5307 only channels 0 and 1 connect to external DREQ pins.DREQ
signals for channels 2 and 3 are connected to the UART0 and UART1 bus interrupt signals.
TT[1:0]/
PP[1:0]
O
Transfer type. A DMA access is indicated by the transfer type pins, TT[1:0] = 01. The transfer
modifier, TM[2:0] configurations shown below are meaningful only if TT[1:0] = 01, indicating an
external master or DMA access.
TM[2:0]
/PP[4:2]
O
Multiplexed transfer attribute pins. The encodings below are valid when TT[1:0] = 01 and
internal DMA channels are driving the bus. DMA transfer information on TM[2:1] can be
provided on every DMA transfer or only on the last transfer by programming DCR[AT].
TM[2:1]Encoding
00
DMA acknowledge information not provided
01
DMA transfer, channel 0
10
DMA transfer, channel 1
11
Reserved
TM0 Encoding for DMA as master (TT = 01)
0
Single-address access negated
1
Single-address access
For TT[1:0] = 01, the TM0 encoding is independent of TM[2:1]. If DCR[SAA] is set, TM0
designates a single-address DMA access.
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DMA Transfer Overview
12.3 DMA Transfer Overview
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The DMA module usually transfers data faster than the ColdFire core can under software
control. The term ‘direct memory access’ refers to peripheral device’s ability to access
system memory directly, greatly improving overall system performance. The DMA module
consists of four independent, functionally equivalent channels, so references to DMA in
this chapter apply to any of the channels. It is not possible to implicitly address all four
channels at once. The MCF5307 on-chip peripherals do not support single-address
transfers.
The processor generates DMA requests internally by setting DCR[START]; a device can
generate a DMA request externally by using DREQ pins. The processor can program bus
bandwidth for each channel. The channels support cycle-steal and continuous transfer
modes; see Section 12.5.1, “Transfer Requests (Cycle-Steal and Continuous Modes).”
The DMA controller supports dual- and single-address transfers as follows. In both, the
DMA channel supports 32 address bits and 32 data bits.
•
Dual-address transfers—A dual-address transfer consists of a read followed by a
write and is initiated by an internal request using the START bit or by an external
device using DREQ. Two types of transfer can occur, a read from a source device or
a write to a destination device; see Figure 12-2.
Control and Data
Memory/
Peripheral
DMA
Control and Data
Memory/
Peripheral
Figure 12-2. Dual-Address Transfer
•
Single-address transfers—An external device can initiate a single-address transfer
by asserting DREQ. The MCF5307 provides address and control signals for
single-address transfers. The external device reads to or writes from the specified
address, as Figure 12-3 shows. External logic is required.
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DMA Controller Module Programming Model
Write:
Control Signals
Memory
DMA
Data
Control Signals
Peripheral
Read:
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Control Signals
Memory
DMA
Data
Control Signals
Peripheral
Figure 12-3. Single-Address Transfers
Any operation involving the DMA module follows the same three steps:
1. Channel initialization—Channel registers are loaded with control information,
address pointers, and a byte-transfer count.
2. Data transfer—The DMA accepts requests for operand transfers and provides
addressing and bus control for the transfers.
3. Channel termination—Occurs after the operation is finished, either successfully or
due to an error. The channel indicates the operation status in the channel’s DSR,
described in Section 12.4.5, “DMA Status Registers (DSR0–DSR3).”
12.4 DMA Controller Module Programming Model
This section describes each internal register and its bit assignment. Note that there is no way
to prevent a write to a control register during a DMA transfer. Table 12-2 shows the
mapping of DMA controller registers. Note the differences for the byte count registers
depending on the value of MPARK[BCR24BIT].
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DMA Controller Module Programming Model
Table 12-2. Memory Map for DMA Controller Module Registers
DMA
Channel
MBAR
Offset
0
0x300
Source address register 0 (SAR0) [p. 12-6]
0x304
Destination address register 0 (DAR0) [p. 12-7]
0x308
DMA control register 0 (DCR0) [p. 12-8]
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0x30C
1
[31:24]
[15:8]
Byte count register 0 (BCR24BIT = 0) 1
[7:0]
Reserved
0x30C
Reserved
Byte count register 0 (BCR24BIT = 1) 1 (BCR0) [p. 12-7]
0x310
DMA status register 0
(DSR0) [p. 12-10]
Reserved
0x314
DMA interrupt vector
register 0 (DIVR0)
[p. 12-11]
Reserved
0x340
Source address register 1 (SAR1) [p. 12-6]
0x344
Destination address register 1 (DAR1) [p. 12-7]
0x348
0x34C
2
[23:16]
DMA control register 1 (DCR1) [p. 12-8]
Byte count register 1 (BCR24BIT = 0) 1
Reserved
0x34C
Reserved
Byte count register 1 (BCR24BIT = 1) 1 (BCR1) [p. 12-7]
0x350
DMA status register 1
(DSR1) [p. 12-10]
Reserved
0x354
DMA interrupt vector
register 1 (DIVR1)
[p. 12-11]
Reserved
0x380
Source address register 2 (SAR2) [p. 12-6]
0x384
Destination address register 2 (DAR2) [p. 12-7]
0x388
0x38C
DMA control register 2 (DCR2) [p. 12-8]
Byte count register 2 (BCR24BIT = 0) 1
Reserved
0x38C
Reserved
Byte count register 2 (BCR24BIT = 1) 1 (BCR2) [p. 12-7]
0x390
DMA status register 2
(DSR2) [p. 12-10]
Reserved
0x394
DMA interrupt vector
register 2 (DIVR2)
[p. 12-11]
Reserved
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DMA Controller Module Programming Model
Table 12-2. Memory Map for DMA Controller Module Registers (Continued)
DMA
Channel
3
MBAR
Offset
[31:24]
[23:16]
0x3C0
Source address register 3 (SAR3) [p. 12-6]
Destination address register 3 (DAR3) [p. 12-7]
0x3C8
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[7:0]
0x3C4
0x3CC
1
[15:8]
DMA control register 3 (DCR3) [p. 12-8]
Byte count register 3 (BCR24BIT = 0) 1
Reserved
0x3CC
Reserved
Byte count register 3 (BCR24BIT = 1) 1 (BCR3) [p. 12-7]
0x3D0
DMA status register 3
(DSR3) [p. 12-10]
Reserved
0x3D4
DMA interrupt vector
register 3 (DIVR3)
[p. 12-11]
Reserved
On the original MCF5307 mask set (H55J), the BCR of the DMA channels can accommodate only 16 bits.
However, because the revised MCF5307 supports a 24-bit byte count range, the position of the BCR in the
memory map depends on whether a 16- or 24-bit byte counter is selected. The 24-bit byte count can be
selected by setting BCR24BIT = 1, making DCR[AT] available. The AT bit selects whether DMA channels
assert acknowledge during the entire transfer or only at the final transfer of a DMA transaction.
New applications should take advantage of the full range of the 24-bit byte counter, including the AT bit. The
16-bit byte count option (BCR24BIT = 0) retains compatibility with older MCF5307 revisions.
NOTE:
External masters cannot access MCF5307 on-chip memories or
MBAR, but they can access DMA module registers.
12.4.1 Source Address Registers (SAR0–SAR3)
SARn, Figure 12-4, contains the address from which the DMA controller requests data. In
single-address mode, SARn provides the address regardless of the direction.
31
0
Field
SAR
Reset
0000_0000_0000_0000_0000_0000_0000_0000
R/W
Address
R/W
MBAR + 0x300, 0x340, 0x380, 0x3C0
Figure 12-4. Source Address Registers (SARn)
NOTE:
SAR/DAR address ranges cannot be programmed to on-chip
SRAM because it cannot be accessed by on-chip DMA.
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12.4.2 Destination Address Registers (DAR0–DAR3)
For dual-address transfers only, DARn, Figure 12-5, holds the address to which the DMA
controller sends data.
31
0
Field
DAR
Reset
0000_0000_0000_0000_0000_0000_0000_0000
R/W
R/W
Address
MBAR + 304, 0x344, 0x384, 0x3C4
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Figure 12-5. Destination Address Registers (DARn)
NOTE:
On-chip DMAs do not maintain coherency with MCF5307
caches and so must not transfer data to cacheable memory.
12.4.3 Byte Count Registers (BCR0–BCR3)
BCRn, Figure 12-6 and Figure 12-7, holds the number of bytes yet to be transferred for a
given block.The offset within the memory map is based on the value of
MPARK[BCR24BIT]. BCRn decrements on the successful completion of the address
transfer of either a write transfer in dual-address mode or any transfer in single-address
mode. BCRn decrements by 1, 2, 4, or 16 for byte, word, longword, or line accesses,
respectively.
Figure 12-6 shows BCR for BCR24BIT = 1.
31
24 23
0
Field
—
BCR
Reset
—
0000_0000_0000_0000_0000_0000
R/W
Address
R/W
MBAR + 0x30C, 0x34C, 0x38C, 0x3AC
Figure 12-6. Byte Count Registers (BCRn)—BCR24BIT = 1
Figure 12-7 shows BCR for BCR24BIT = 0.
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DMA Controller Module Programming Model
Bit
15
14
13
12
11
10
9
8
7
6
Field
BCR
Reset
0000_0000_0000_0000
5
4
3
2
1
0
R/W
Addr
MBAR + 0x30C, 0x34C, 0x38C, 0x3AC
Figure 12-7. BCRn—BCR24BIT = 0
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DSR[DONE], shown in Figure 12-9, is set when the block transfer is complete.
When a transfer sequence is initiated and BCRn[BCR] is not divisible by 16, 4, or 2 when
the DMA is configured for line, longword, or word transfers, respectively, DSRn[CE] is set
and no transfer occurs. See Section 12.4.5, “DMA Status Registers (DSR0–DSR3).”
12.4.4 DMA Control Registers (DCR0–DCR3)
DCRn, Figure 12-8, is used for configuring the DMA controller module. Note that
DCR[AT] is available only if BCR24BIT = 1.
31
30
Field INT EEXT
29
28
CS
AA
27
25
BWC
Reset
23
22
21
20
SSIZE
19
DINC
18
17
DSIZE
16
START
0000_0000_0000_0000
R/W
R/W
15
14
0
Field AT 1
Reset
24
SAA S_RW SINC
—
N/A
0
R/W
R/W
Address
MBAR + 0x308, 0x348, 0x388, 0x3A8
Figure 12-8. DMA Control Registers (DCRn)
1
Available only if BCR24BIT = 1, otherwise reserved.
Table 12-3 describes DCR fields.
Table 12-3. DCRn Field Descriptions
Bits
Name
Description
31
INT
Interrupt on completion of transfer. Determines whether an interrupt is generated by completing a
transfer or by the occurrence of an error condition.
0 No interrupt is generated.
1 Internal interrupt signal is enabled.
30
EEXT
Enable external request. Care should be taken because a collision can occur between the START
bit and DREQ when EEXT = 1.
0 External request is ignored.
1 Enables external request to initiate transfer. Internal request is always enabled. It is initiated by
writing a 1 to the START bit.
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Table 12-3. DCRn Field Descriptions (Continued)
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Bits
Name
Description
29
CS
Cycle steal.
0 DMA continuously makes read/write transfers until the BCR decrements to 0.
1 Forces a single read/write transfer per request. The request may be internal by setting the START
bit, or external by asserting DREQ.
28
AA
Auto-align. AA and SIZE determine whether the source or destination is auto-aligned, that is,
transfers are optimized based on the address and size. See Section 12.5.4.2, “Auto-Alignment.”
0 Auto-align disabled
1 If SSIZE indicates a transfer no smaller than DSIZE, source accesses are auto-aligned;
otherwise, destination accesses are auto-aligned. Source alignment takes precedence over
destination alignment. If auto-alignment is enabled, the appropriate address register increments,
regardless of DINC or SINC.
27–25 BWC
Bandwidth control. Indicates the number of bytes in a block transfer. When the byte count reaches
a multiple of the BWC value, the DMA releases the bus. For example, if BCR24BIT is 0, BWC is
001 (512 bytes or value of 0x0200), and BCR is 0x1000, the bus is relinquished after BCR values of
0x2000, 0x1E00, 0x1C00, 0x1A00, 0x1800, 0x1600, 0x1400, 0x1200, 0x1000, 0x0E00, 0x0C00,
0x0A00, 0x0800, 0x0600, 0x0400, and 0x0200. If BCR24BIT is 0, BWC is 110, and BCR is 33000,
the bus is released after 232 bytes because the BCR is at 32768, a multiple of 16384.
BWC BCR24BIT = 0
BCR24BIT = 1
000
DMA has priority. It does not negate its request until its transfer completes.
001
512
16384
010
1024
32768
011
2048
65536
100
4096
131072
101
8192
262144
110
16384
524288
111
32768
1048576
24
SAA
Single-address access. Determines whether the DMA channel is in dual- or single-address mode
0 Dual-address mode.
1 Single-address mode. The DMA provides an address from the SAR and directional control, bit
S_RW, to allow two peripherals (one might be memory) to exchange data within a single access.
Data is not stored by the DMA.
23
S_RW
Single-address access read/write value. Valid only if SAA = 1. Specifies the value of the read signal
during single-address accesses. This provides directional control to the bus controller.
0 Forces the read signal to 0.
1 Forces the read signal to 1.
22
SINC
Source increment. Controls whether a source address increments after each successful transfer.
0 No change to SAR after a successful transfer.
1 The SAR increments by 1, 2, 4, or 16, as determined by the transfer size.
21–20 SSIZE
Source size. Determines the data size of the source bus cycle for the DMA control module.
00 Longword
01 Byte
10 Word
11 Line
19
Destination increment. Controls whether a destination address increments after each successful
transfer.
0 No change to the DAR after a successful transfer.
1 The DAR increments by 1, 2, 4, or 16, depending upon the size of the transfer.
DINC
18–17 DSIZE
Destination size. Determines the data size of the destination bus cycle for the DMA controller.
00 Longword
01 Byte
10 Word
11 Line
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Table 12-3. DCRn Field Descriptions (Continued)
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Bits
Name
Description
16
START
Start transfer.
0 DMA inactive
1 The DMA begins the transfer in accordance to the values in the control registers. START is
cleared automatically after one clock and is always read as logic 0.
15
AT
AT is available only if BCR24BIT = 1.
DMA acknowledge type. Controls whether acknowledge information is provided for the entire
transfer or only the final transfer.
0 Entire transfer. DMA acknowledge information is displayed anytime the channel is selected as the
result of an external request.
1 Final transfer (when BCR reaches zero). For dual-address transfer, the acknowledge information
is displayed for both the read and write cycles.
14–0
—
Reserved, should be cleared.
12.4.5 DMA Status Registers (DSR0–DSR3)
In response to an event, the DMA controller writes to the appropriate DSRn bit,
Figure 12-9. Only a write to DSRn[DONE] results in action.
7
6
5
4
3
2
1
0
Field
—
CE
BES
BED
—
REQ
BSY
DONE
Reset
—
0
0
0
—
0
0
0
R/W
R/W
Address
MBAR + 0x310, 0x350, 0x390, 0x3D0
Figure 12-9. DMA Status Registers (DSRn)
Table 12-4 describes DSRn fields.
Table 12-4. DSRn Field Descriptions
Bits
Name
Description
7
—
Reserved, should be cleared.
6
CE
Configuration error. Occurs when BCR, SAR, or DAR does not match the requested transfer size,
or if BCR = 0 when the DMA receives a start condition. CE is cleared at hardware reset or by
writing a 1 to DSR[DONE].
0 No configuration error exists.
1 A configuration error has occurred.
5
BES
Bus error on source
0 No bus error occurred.
1 The DMA channel terminated with a bus error either during the read portion of a transfer or
during an access in single-address mode (SAA = 1).
4
BED
Bus error on destination
0 No bus error occurred.
1 The DMA channel terminated with a bus error during the write portion of a transfer.
3
—
Reserved, should be cleared.
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Table 12-4. DSRn Field Descriptions (Continued)
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Bits
Name
Description
2
REQ
Request
0 No request is pending or the channel is currently active. Cleared when the channel is selected.
1 The DMA channel has a transfer remaining and the channel is not selected.
1
BSY
Busy
0 DMA channel is inactive. Cleared when the DMA has finished the last transaction.
1 BSY is set the first time the channel is enabled after a transfer is initiated.
0
DONE
Transactions done. Set when all DMA controller transactions complete normally, as determined by
transfer count and error conditions. When BCR reaches zero, DONE is set when the final transfer
completes successfully. DONE can also be used to abort a transfer by resetting the status bits.
When a transfer completes, software must clear DONE before reprogramming the DMA.
0 Writing or reading a 0 has no effect.
1 DMA transfer completed. Writing a 1 to this bit clears all DMA status bits and can be used as an
interrupt handler to clear the DMA interrupt and error bits.
12.4.6 DMA Interrupt Vector Registers (DIVR0–DIVR3)
The contents of a DMA interrupt vector register (DIVRn), Figure 12-10, are driven onto the
internal bus in response to an interrupt acknowledge cycle.
7
0
Field
Interrupt Vector Bits
Reset
0000_1111
R/W
Address
R/W
MBAR + 0x314, 0x354, 0x394, 0x3D4
Figure 12-10. DMA Interrupt Vector Registers (DIVRn)
12.5 DMA Controller Module Functional Description
In the following discussion, the term ‘DMA request’ implies that DCR[START] or
DCR[EEXT] is set, followed by assertion of DREQ. The START bit is cleared when the
channel begins an internal access.
Before initiating a dual-address access, the DMA module verifies that DCR[SSIZE,DSIZE]
are consistent with the source and destination addresses. If the source and destination are
not the same size, the configuration error bit, DSR[CE], is also set. If misalignment is
detected, no transfer occurs, CE is set, and, depending on the DCR configuration, an
interrupt event is issued. Note that if the auto-align bit, DCR[AA], is set, error checking is
performed on appropriate registers.
A read/write transfer reads bytes from the source address and writes them to the destination
address. The number of bytes is the larger of the sizes specified by SSIZE and DSIZE. See
Section 12.4.4, “DMA Control Registers (DCR0–DCR3).”
Source and destination address registers (SAR and DAR) can be programmed in the DCR
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DMA Controller Module Functional Description
to increment at the completion of a successful transfer. BCR decrements when an address
transfer write completes for a single-address access (DCR[SAA] = 0) or when SAA = 1.
12.5.1 Transfer Requests (Cycle-Steal and Continuous
Modes)
The DMA channel supports internal and external requests. A request is issued by setting
DCR[START] or by asserting DREQ. Setting DCR[EEXT] enables recognition of external
interrupts. Internal interrupts are always recognized. Bus usage is minimized for either
internal or external requests by selecting between cycle-steal and continuous modes.
Freescale Semiconductor, Inc...
•
•
Cycle-steal mode (DCR[CS] = 1)—Only one complete transfer from source to
destination occurs for each request. If DCR[EEXT] is set, a request can be either
internal or external. Internal request is selected by setting DCR[START]. An
external request is initiated by asserting DREQ while EEXT is set.
Continuous mode (DCR[CS] = 0)—After an internal or external request, the DMA
continuously transfers data until BCR reaches zero or a multiple of DCR[BWC] or
DSR[DONE] is set. If BCR is a multiple of BWC, the DMA request signal is
negated until the bus cycle terminates to allow the internal arbiter to switch masters.
DCR[BWC] = 000 specifies the maximum transfer rate; other values specify a
transfer rate limit.
The DMA performs the specified number of transfers, then relinquishes bus control.
The DMA negates its internal bus request on the last transfer before the BCR reaches
a multiple of the boundary specified in BWC. On completion, the DMA reasserts its
bus request to regain mastership at the earliest opportunity. The minimum time that
the DMA loses bus control is one bus cycle.
12.5.2 Data Transfer Modes
Each channel supports dual- and single-address transfers, described in the next sections.
12.5.2.1 Dual-Address Transfers
Dual-address transfers consist of a source operand read and a destination operand write.
The DMA controller module begins a dual-address transfer sequence when DCR[SAA] is
cleared during a DMA request. If no error condition exists, DSR[REQ] is set.
•
12-12
Dual-address read—The DMA controller drives the SAR value onto the internal
address bus. If DCR[SINC] is set, the SAR increments by the appropriate number
of bytes upon a successful read cycle. When the appropriate number of read cycles
complete (multiple reads if the destination size is wider than the source), the DMA
initiates the write portion of the transfer.
If a termination error occurs, DSR[BES,DONE] are set and DMA transactions stop.
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DMA Controller Module Functional Description
•
Dual-address write—The DMA controller drives the DAR value onto the address
bus. If DCR[DINC] is set, DAR increments by the appropriate number of bytes at
the completion of a successful write cycle. The BCR decrements by the appropriate
number of bytes. DSR[DONE] is set when BCR reaches zero. If the BCR is greater
than zero, another read/write transfer is initiated. If the BCR is a multiple of
DCR[BWC], the DMA request signal is negated until termination of the bus cycle
to allow the internal arbiter to switch masters.
If a termination error occurs, DSR[BES,DONE] are set and DMA transactions stop.
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12.5.2.2 Single-Address Transfers
Single-address transfers consist of one DMA bus cycle, allowing either a read or a write
cycle to occur. The DMA controller begins a single-address transfer sequence when
DCR[SAA] is set during a DMA request. If no error condition exists, DSR[REQ] is set.
When the channel is enabled, DSR[BSY] is set and REQ is cleared. SAR contents are then
driven onto the address bus and the value of DCR[S_RW] is driven on R/W. The BCR
decrements on each successful address access until it is zero, when DSR[DONE] is set.
If a termination error occurs, DSR[BES,DONE] are set and DMA transactions stop.
12.5.3 Channel Initialization and Startup
Before a block transfer starts, channel registers must be initialized with information
describing configuration, request-generation method, and the data block.
12.5.3.1 Channel Prioritization
The four DMA channels are prioritized in ascending order (channel 0 having highest
priority and channel 3 having the lowest) or as determined by DCR[BWC]. If BWC for a
DMA channel is 000, that channel has priority only over the channel immediately
preceding it. For example, if DCR3[BWC] = 000, DMA channel 3 has priority over DMA
channel 2 (assuming DCR2[BWC] ≠ 000) but not over DMA channel 1.
If DCR1[BWC] = DCR2[BWC] = 000, DMA 1 has priority over DMA 0 and DMA 2.
DCR2[BWC] = 000 in this case does not affect prioritization.
Prioritization of simultaneous external requests is either ascending or as determined by
each channel’s BWC bits as described in the previous paragraphs.
12.5.3.2 Programming the DMA Controller Module
Note the following general guidelines for programming the DMA:
•
•
No mechanism exists to prevent writes to control registers during DMA accesses.
If the BWC of sequential channels are equal, channel priority is in ascending order.
The SAR is loaded with the source (read) address. If the transfer is from a peripheral device
to memory, the source address is the location of the peripheral data register. If the transfer
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DMA Controller Module Functional Description
is from memory to either a peripheral device or memory, the source address is the starting
address of the data block. This can be any aligned byte address. In single-address mode, this
data register is used regardless of transfer direction.
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The DAR should contain the destination (write) address. If the transfer is from a peripheral
device to memory, or memory to memory, the DAR is loaded with the starting address of
the data block to be written. If the transfer is from memory to a peripheral device, DAR is
loaded with the address of the peripheral data register. This address can be any aligned byte
address. DAR is not used in single-address mode.
SAR and DAR change after each cycle depending on DCR[SSIZE,DSIZE,SINC,DINC]
and on the starting address. Increment values can be 1, 2, 4, or 16 for byte, word, longword,
or line transfers, respectively. If the address register is programmed to remain unchanged
(no count), the register is not incremented after the data transfer.
BCRn[BCR] must be loaded with the number of byte transfers to occur. It is decremented
by 1, 2, 4, or 16 at the end of each transfer, depending on the transfer size. DSR must be
cleared for channel startup.
As soon as the channel has been initialized, it is started by writing a one to DCR[START]
or asserting DREQ, depending on the status of DCR[EEXT]. Programming the channel for
internal request causes the channel to request the bus and start transferring data
immediately. If the channel is programmed for external request, DREQ must be asserted
before the channel requests the bus.
Changes to DCR are effective immediately while the channel is active. To avoid problems
with changing a DMA channel setup, write a one to DSR[DONE] to stop the DMA channel.
12.5.4 Data Transfer
This section includes timing diagrams that illustrate the interaction of signals in DMA data
transfers. It also describes auto-alignment and bandwidth control.
12.5.4.1 External Request and Acknowledge Operation
Channels 0 and 1 initiate transfers to an external module by means of DREQ[1:0]. The
request for channels 2 and 3 are connected internally to the UART0 and UART1 interrupt
signals, respectively. If DCR[EEXT] = 1 and the channel is idle, the DMA initiates a
transfer when DREQ is asserted.
Figure 12-11 shows the minimum 4-clock cycle delay from when DREQ is sampled
asserted to when a DMA bus cycle begins. This delay may be longer, depending on DMA
priority, bus arbitration, DRAM refresh operations, and other factors.
12-14
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DMA Controller Module Functional Description
0
1
2
3
4
5
6
7
8
9
10
11
CLKIN
DREQ0
TM0
TT1
TT0
TS
CS
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TA
R/W
A[31:0]
Read
Write
Figure 12-11. DREQ Timing Constraints, Dual-Address DMA Transfer
Although Figure 12-11 does not show TM0 signaling a DMA acknowledgement, this signal
can provide an external request acknowledge response, as shown in subsequent diagrams.
To initiate a request, DREQ need only be asserted long enough to be sampled on one rising
clock edge. However, note the following regarding the negation of DREQ:
•
•
In cycle-steal mode (DCR[CS] = 1), the read/write transaction is limited to a single
transfer. DREQ must be negated appropriately to avoid generating another request.
— For dual-address transfers, DREQ must be negated before TS is asserted for the
write portion, as shown in Figure 12-11, clock cycle 7.
— For single-address transfers, DREQ must be negated before TS is asserted for the
transfer, as shown in Figure 12-13, clock cycle 4.
In burst mode, (DCR[CS] = 0), multiple read/write transfers can occur on the bus as
programmed. DREQ need not be negated until DSR[DONE] is set, indicating the
block transfer is complete. Another transfer cannot be initiated until the DMA
registers are reprogrammed.
Figure 12-12 shows a dual-address, peripheral-to-SDRAM DMA transfer. The DMA is not
parked on the bus, so the diagram shows how the CPU can generate multiple bus cycles
during DMA transfers. It also shows TM0 timing. The TT signals indicate whether the CPU
(0) or DMA (1) has bus mastership. TM2 indicates dual-address mode.
If DCR[AT] is 1, TM is asserted during the final transfer. If DCR[AT] is 0, TM asserts
during all DMA accesses.
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DMA Controller Module Functional Description
CLKIN
TS
AS
TIP
A[31:0]
R/W
SIZ[1:0]
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D[31:0]
CSx
TA
DRAMW
Precharge
SRAS
SCAS
RAS[1:0]
CAS[3:0]
TT[1:0]
0
1
0
1
0
TM2
TM0
DREQ0
CPU
DMA Read
CPU
DMA Write
CPU
Figure 12-12. Dual-Address, Peripheral-to-SDRAM, Lower-Priority DMA Transfer
Figure 12-13 shows a single-address DMA transfer in which the peripheral is reading from
memory. Note that TM2 is high, indicating a single-address transfer. Note that DREQ is
negated in clock 4, before the assertion of TS in clock 6.
12-16
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DMA Controller Module Functional Description
0
1
2
3
4
5
6
7
8
9
10
11
CLKIN
DREQ0
TM0
TS
A[31:0], SIZ[1:0]
TIP
R/W
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TM2
TT0
TT1
CSx, AS
OE, BE/BWE
TA
D[31:0]
Figure 12-13. Single-Address DMA Transfer
12.5.4.2 Auto-Alignment
Auto-alignment allows block transfers to occur at the optimal size based on the address,
byte count, and programmed size. To use this feature, DCR[AA] must be set. The source is
auto-aligned if SSIZE indicates a transfer size larger than DSIZE. Source alignment takes
precedence over the destination when the source and destination sizes are equal. Otherwise,
the destination is auto-aligned. The address register chosen for alignment increments
regardless of the increment value. Configuration error checking is performed on registers
not chosen for alignment.
If BCR is greater than 16, the address determines transfer size. Bytes, words, or longwords
are transferred until the address is aligned to the programmed size boundary, at which time
accesses begin using the programmed size.
If BCR is less than 16 at the start of a transfer, the number of bytes remaining dictates
transfer size. For example, AA = 1, SAR = 0x0001, BCR = 0x00F0, SSIZE = 00
(longword), and DSIZE = 01 (byte). Because SSIZE > DSIZE, the source is auto-aligned.
Error checking is performed on destination registers. The access sequence is as follows:
1. Read byte from 0x0001—write 1 byte, increment SAR.
2. Read word from 0x0002—write 2 bytes, increment SAR.
3. Read longword from 0x0004—write 4 bytes, increment SAR.
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DMA Controller Module Functional Description
4. Repeat longwords until SAR = 0x00F0.
5. Read byte from 0x00F0—write byte, increment SAR.
If DSIZE is another size, data writes are optimized to write the largest size allowed based
on the address, but not exceeding the configured size.
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12.5.4.3 Bandwidth Control
Bandwidth control makes it possible to force the DMA off the bus to allow access to
another device. DCR[BWC] provides seven levels of block transfer sizes. If the BCR
decrements to a multiple of the decode of the BWC, the DMA bus request negates until the
bus cycle terminates. If a request is pending, the arbiter may then pass bus mastership to
another device. If auto-alignment is enabled, DCR[AA] = 1, the BCR may skip over the
programmed boundary, in which case, the DMA bus request is not negated.
If BWC = 000, the request signal remains asserted until BCR reaches zero. DMA has
priority over the core. Note that in this scheme, the arbiter can always force the DMA to
relinquish the bus. See Section 6.2.10.1, “Default Bus Master Park Register (MPARK).”
12.5.5 Termination
An unsuccessful transfer can terminate for one of the following reasons:
•
•
12-18
Error conditions—When the MCF5307 encounters a read or write cycle that
terminates with an error condition, DSR[BES] is set for a read and DSR[BED] is set
for a write before the transfer is halted. If the error occurred in a write cycle, data in
the internal holding register is lost.
Interrupts—If DCR[INT] is set, the DMA drives the appropriate internal interrupt
signal. The processor can read DSR to determine whether the transfer terminated
successfully or with an error. DSR[DONE] is then written with a one to clear the
interrupt and the DONE and error bits.
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Chapter 13
Timer Module
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This chapter describes the configuration and operation of the two general-purpose timer
modules (timer 0 and timer 1). It includes programming examples.
13.1 Overview
The timer module incorporates two independent, general-purpose 16-bit timers, timer 0 and
timer 1. The output of an 8-bit prescaler clocks each timer. There are two sets of registers,
one for each timer. The timers can operate from the system bus clock (BCLKO) or from an
external clocking source using one of the TIN signals. If BCLKO is selected, it can be
divided by 16 or 1.
Figure 13-1 is a block diagram of one of the two identical ti5mer modules.
GENERAL-PURPOSE TIMER
System Bus
Clock
(÷1 or ÷16)
Timer Mode Register (TMRn)
Prescaler
Mode Bits
Timer
Clock
Generator
TIN
clock
Capture
Detection
15
0
Timer Counter (TCNn)
(contains incrementing value)
15
TOUT
IRQn
Divider
0
Timer Capture Register (TCRn)
(latches TCN value when triggered by TIN)
15
0
Timer Reference Register (TRRn)
(reference value for comparison with TCN)
Timer Event Register (TERn)
(indicates capture or when TCN = TRRn)
Figure 13-1. Timer Block Diagram
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General-Purpose Timer Units
13.1.1 Key Features
Each general-purpose 16-bit timer unit has the following features:
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•
•
•
•
•
•
•
Maximum period of 5.96 seconds at 45 MHz
27-nS resolution at 45 MHz
Programmable sources for the clock input, including external clock
Input-capture capability with programmable trigger edge on input pin
Output-compare with programmable mode for the output pin
Free run and restart modes
Maskable interrupts on input capture or reference-compare
13.2 General-Purpose Timer Units
The general-purpose timer units provide the following features:
•
•
•
•
•
•
Each timer can be programmed to count and compare to a reference value stored in
a register or capture the timer value at an edge detected on TIN.
System bus clock can be divided by 16 or 1. This clock is input to the prescaler.
TIN is fed directly into the 8-bit prescaler. The maximum value of TIN is 1/5 of
CLKIN, as described in Chapter 20, “Electrical Specifications.”
The 8-bit prescaler clock divides the clocking source and is user-programmable
from 1 to 256.
Programmed events generate interrupts.
The timer output signal (TOUT) can be configured to toggle or pulse on an event.
13.3 General-Purpose Timer Programming Model
The following features are programmable through the timer registers, shown in Table 13-1:
•
•
13-2
Prescaler—The prescaler clock input is selected from BCLKO (divided by 1 or 16)
or from the corresponding timer input, TIN. TIN is synchronized to BCLKO. The
synchronization delay is between two and three BCLKO clocks. The corresponding
TMRn[ICLK] selects the clock input source. A programmable prescaler divides the
clock input by values from 1 to 256. The prescaler is an input to the 16-bit counter.
Capture mode—Each timer has a 16-bit timer capture register (TCR0 and TCR1)
that latches the counter value when the corresponding input capture edge detector
senses a defined TIN transition. The capture edge bits (TMRn[CE]) select the type
of transition that triggers the capture, sets the timer event register capture event bit,
TERn[CAP], and issues a maskable interrupt.
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General-Purpose Timer Programming Model
•
•
Reference compare—A timer can be configured to count up to a reference value, at
which point TERn[REF] is set. If TMRn[ORI] is one, an interrupt is issued. If the
free run/restart bit TMRn[FRR] is set, a new count starts. If it is clear, the timer
keeps running.
Output mode—When a timer reaches the reference value selected by TMRn[OM],
it can send an output signal on TOUTn. TOUTn can be an active-low pulse or a
toggle of the current output under program control.
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NOTE:
Although external devices cannot access MCF5307 on-chip
memories or MBAR, they can access timer module registers.
The timer module registers, shown in Table 13-1, can be modified at any time.
Table 13-1. General-Purpose Timer Module Memory Map
MBAR
Offset
[31:24]
[23:16]
[15:8]
[7:0]
0x140
Timer 0 mode register (TMR0) [p. 13-3]
0x144
Timer 0 reference register (TRR0) [p. 13-4]
Reserved
0x148
Timer 0 capture register (TCR0) [p. 13-4]
Reserved
0x14C
Timer 0 counter (TCN0) [p. 13-5]
Reserved
Reserved
0x150
Reserved
Timer 0 event register
(TER0) [p. 13-5]
Reserved
0x180
Timer 1 mode register (TMR1) [p. 13-3]
0x184
Timer 1 reference register (TRR1) [p. 13-4]
Reserved
0x188
Timer 1 capture register (TCR1) [p. 13-4]
Reserved
0x18C
Reserved
Timer 1 counter (TCN1) [p. 13-5]
Reserved
0x190
Reserved
Timer 1 event register
(TER1) [p. 13-5]
Reserved
13.3.1 Timer Mode Registers (TMR0/TMR1)
Timer mode registers (TMR0/TMR1), Figure 13-2, program the prescaler and various
timer modes.
15
Field
8
6
CE
Reset
5
4
3
OM ORI FRR
2
1
CLK
0
RST
0000_0000_0000_0000
R/W
Address
7
PS
R/W
MBAR + 0x140 (TMR0); + 0x180 (TMR1)
Figure 13-2. Timer Mode Registers (TMR0/TMR1)
Table 13-2 describes TMRn fields.
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General-Purpose Timer Programming Model
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Table 13-2. TMRn Field Descriptions
Bits
Name
Description
15–8
PS
Prescaler value. The prescaler is programmed to divide the clock input (BCLKO/(16 or 1) or clock on
TIN) by values from 1 (PS = 0000_0000) to 256 (PS = 1111_1111).
7–6
CE
Capture edge and enable interrupt
00 Disable interrupt on capture event
01 Capture on rising edge only and enable interrupt on capture event
10 Capture on falling edge only and enable interrupt on capture event
11 Capture on any edge and enable interrupt on capture event
5
OM
Output mode
0 Active-low pulse for one BCLKO cycle (22 nS at 45 MHz, 33 nS at 30 MHz, 44 nS at 22.5 MHz).
1 Toggle output.
4
ORI
Output reference interrupt enable. If ORI is set when TERn[REF] = 1, an interrupt occurs.
0 Disable interrupt for reference reached (does not affect interrupt on capture function).
1 Enable interrupt upon reaching the reference value.
3
FRR
Free run/restart
0 Free run. Timer count continues to increment after reaching the reference value.
1 Restart. Timer count is reset immediately after reaching the reference value.
2–1
CLK
Input clock source for the timer
00 Stop count
01 System bus clock divided by 1
10 System bus clock divided by 16. Note that this clock source is not synchronized to the timer; thus
successive time-outs may vary slightly.
11 TIN pin (falling edge)
0
RST
Reset timer. Performs a software timer reset similar to an external reset, although other register
values can still be written while RST = 0. A transition of RST from 1 to 0 resets register values. The
timer counter is not clocked unless the timer is enabled.
0 Reset timer (software reset)
1 Enable timer
13.3.2 Timer Reference Registers (TRR0/TRR1)
Each timer reference register (TRR0/TRR1), Figure 13-3, contains the reference value
compared with the respective free-running timer counter (TCN0/TCN1) as part of the
output-compare function. The reference value is not matched until TCNn equals TRRn.
=
15
0
Field
REF
Reset
1111_1111_1111_1111
R/W
Address
R/W
MBAR + 0x144 (TRR0),+ 0x184 (TRR1)
Figure 13-3. Timer Reference Registers (TRR0/TRR1)
13.3.3 Timer Capture Registers (TCR0/TCR1)
Each timer capture register (TCR0/TCR1), Figure 13-4, latches the corresponding TCNn
value during a capture operation when an edge occurs on TIN, as programmed in TMRn.
13-4
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General-Purpose Timer Programming Model
BCLKO is assumed to be the clock source. TIN cannot simultaneously function as a
clocking source and as an input capture pin.
15
0
Field
CAP (16-bit capture counter value)
Reset
0000_0000_0000_0000
R/W
Read only
Address
MBAR + 0x148 (TCR0); + 0x188 (TCR1)
Figure 13-4. Timer Capture Register (TCR0/TCR1)
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13.3.4 Timer Counters (TCN0/TCN1)
The current value of the 16-bit, incrementing timer counters (TCN0/TCN1), Figure 13-5,
can be read anytime without affecting counting. Writing to TCNn clears it. The timer
counter decrements on the clock source rising edge (BCLKO ÷ 1, BCLKO ÷ 16, or TIN).
15
0
Field
16-bit timer counter value count
Reset
0000_0000_0000_0000
R/W
R/W (to reset)
Address
MBAR + 0x14C (TCN0); + 0x18C (TCN1)
Figure 13-5. Timer Counters (TCN0/TCN1)
13.3.5 Timer Event Registers (TER0/TER1)
Each timer event register (TER0/TER1), Figure 13-6, reports capture or reference events
events the timer recognizes by setting TERn[CAP] or TERn[REF], which it does regardless
of the corresponding interrupt-enable bit values, TMRn[ORI,CE].
Writing a 1 to either REF or CAP clears it (writing a 0 does not affect bit value); both bits
can be cleared at the same time. REF and CAP must be cleared early in the exception
handler, before the timer negates the IRQn to the interrupt controller.
7
Field
Reset
R/W
Address
2
—
1
0
REF
CAP
0000_0000
R/W (ones clear/zeros have no effect)
MBAR + 0x151 (TER0); + 0x191 (TER1)
Figure 13-6. Timer Event Registers (TER0/TER1)
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Code Example
Table 13-3 describes TERn fields.
Table 13-3. TERn Field Descriptions
Bits
Name
Description
7–2
—
1
REF
Output reference event. The counter has reached the TRRn value. Setting TMRn[ORI] enables the
interrupt request caused by this event. Writing a one to REF clears the event condition.
0
CAP
Capture event. The counter value has been latched into TCRn. Setting TMRn[CE] enables the
interrupt request caused by this event. Writing a 1 to CAP clears the event condition.
Reserved
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13.4 Code Example
The following code provides an example of how to initialize timer 0 and how to use the
timer for counting time-out periods.
MBARx EQU 0x10000 ;Defines the module base address at 0x10000
TMR0 EQU MBARx+0x140;Timer 0 register
TMR1 EQU MBARx+0x180 ;Timer 1 register
TRR0 EQU MBARx+0x144 ;Timer 0 reference register
TRR1 EQU MBARx+0x184 ;Timer 1 reference register
TCR0 EQU MBARx+0x148 ;Timer 0 capture register
TCR1 EQU MBARx+0x188 ;Timer 1 capture register
TCN0 EQU MBARx+0x14C ;Timer 0 counter
TCN1 EQU MBARx+0x18C ;Timer 1 counter
TER0 EQU MBARx+0x151 ;Timer 0 event register
TER1 EQU MBARx+0x191 ;Timer 1 event register
* TMR0 is defined as: *
*[PS]= 0xFF, divide clock by 256
*[CE] = 00disable interrupt
*[OM] = 0 output=active-low pulse
*[ORI] = 0, disable ref.interrupt
*[FRR] = 1, restart mode enabled
*[CLK] = 10, BCLKO/16
*[RST] = 0, timer 0 disabled
move.w #0xFF0C,D0
move.w D0,TMR0
move.w #0x0000,D0;writing to the timer counter with any
move.w DO,TCN0 ;value resets it to zero
move.w #AFAF,DO ;set the timer 0 reference to be
move.w #D0,TRR0 ;defined as 0xAFAF
The simple example below uses 0 to count time-out loops. A time-out occurs when the
reference value, 0xAFAF, is reached.
timer0_ex
clr.l DO
clr.l D1
clt.l D2
move.w #0x0000,D0
move,w D0,TCN0;reset the counter to 0x0000
move.b #0x03,D0 ;writing ones to TER0[REF,CAP]
move.b D0,TER0 ;clears the event flags
13-6
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Calculating Time-Out Values
move.w TMR0,D0;save the contents of TMR0 while setting
bset #0,D0 ;the 0 bit. This enables timer 0 and starts counting
move.w D0, TMR0 ;load the value back into the register, setting TMR0[RST]
T0_LOOP
move.b TER0,D1 ;load TER0 and see if
btst #1,D1 ;TER0[REF] has been set
beq T0_LOOP
addi.l #1,D2;Increment D2
cmp.l #5,D2;Did D2 reach 5? (i.e. timer ref has timed)
beq T0_FINISH;If so, end timer0 example. Otherwise jump back.
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move.b #0x02,D0 ;writing one to TER0[REF] clears the event flag
move.b D0,TER0
jmp T0_LOOP
T0_FINISH
HALT;End processing. Example is finished
13.5 Calculating Time-Out Values
The formula below determines time-out periods for various reference values:
Time-out period = (1/clock frequency) x (1 or 16) x (TMRn[PS] + 1) x
(TRRn[REF])
When calculating time-out periods, add 1 to the prescaler to simplify calculating, because
TMRn[PS] = 0x00 yields a prescaler of 1 and TMRn[PS] = 0xFF yields a prescaler of 256.
For example, if a 45-MHz timer clock is divided by 16, TMRn[PS] = 0x7F, and the timer
is referenced at 0xABCD (43,981 decimal), the time-out period is as follows:
Time-out period = (1/45) x (16) x (127 + 1) x (43,981) = 1.67 S
The time-out values in Table 13-5 represent the time it takes the counter value in TCNn
value to go from 0x0000 to the default reference value, TRRn[REF] = 0xFFFF. Time-out
values shown for BCLKO are divided by 1 and by 16 (TMRn[CLK] is 01 or 10,
respectively).
Any clock source (BCLKO ÷ 1, BCLKO ÷ 16, or TIN) can be prescaled using TMRn[PS].
The BCLKO frequency depends on the prescaler value (TMRn[PS]) and on the PLL clock
setting, as described inChapter 7, “Phase-Locked Loop (PLL).”
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock)
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
22.5 MHz
0
0
0.0233
0.03495
0.0466
0.00146
0.00218
0.00291
1
1
0.0466
0.06991
0.09321
0.00291
0.00437
0.00583
2
2
0.06991
0.10486
0.13981
0.00437
0.00655
0.00874
3
3
0.09321
0.13981
0.18641
0.00583
0.00874
0.01165
4
4
0.11651
0.17476
0.23302
0.00728
0.01092
0.01456
5
5
0.13981
0.20972
0.27962
0.00874
0.01311
0.01748
Chapter 13. Timer Module
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13-7
Freescale Semiconductor, Inc.
Calculating Time-Out Values
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock) (Continued)
Freescale Semiconductor, Inc...
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
22.5 MHz
6
6
0.16311
0.24467
0.32622
0.01019
0.01529
0.02039
7
7
0.18641
0.27962
0.37283
0.01165
0.01748
0.0233
8
8
0.20972
0.31457
0.41943
0.01311
0.01966
0.02621
9
9
0.23302
0.34953
0.46603
0.01456
0.02185
0.02913
10
0A
0.25632
0.38448
0.51264
0.01602
0.02403
0.03204
11
0B
0.27962
0.41943
0.55924
0.01748
0.02621
0.03495
12
0C
0.30292
0.45438
0.60584
0.01893
0.0284
0.03787
13
0D
0.32622
0.48934
0.65245
0.02039
0.03058
0.04078
14
0E
0.34953
0.52429
0.69905
0.02185
0.03277
0.04369
15
0F
0.37283
0.55924
0.74565
0.0233
0.03495
0.0466
16
10
0.39613
0.59419
0.79226
0.02476
0.03714
0.04952
17
11
0.41943
0.62915
0.83886
0.02621
0.03932
0.05243
18
12
0.44273
0.6641
0.88546
0.02767
0.04151
0.05534
19
13
0.46603
0.69905
0.93207
0.02913
0.04369
0.05825
20
14
0.48934
0.734
0.97867
0.03058
0.04588
0.06117
21
15
0.51264
0.76896
1.02527
0.03204
0.04806
0.06408
22
16
0.53594
0.80391
1.07188
0.0335
0.05024
0.06699
23
17
0.55924
0.83886
1.11848
0.03495
0.05243
0.06991
24
18
0.58254
0.87381
1.16508
0.03641
0.05461
0.07282
25
19
0.60584
0.90877
1.21169
0.03787
0.0568
0.07573
26
1A
0.62915
0.94372
1.25829
0.03932
0.05898
0.07864
27
1B
0.65245
0.97867
1.30489
0.04078
0.06117
0.08156
28
1C
0.67575
1.01362
1.3515
0.04223
0.06335
0.08447
29
1D
0.69905
1.04858
1.3981
0.04369
0.06554
0.08738
30
1E
0.72235
1.08353
1.4447
0.04515
0.06772
0.09029
31
1F
0.74565
1.11848
1.49131
0.0466
0.06991
0.09321
32
20
0.76896
1.15343
1.53791
0.04806
0.07209
0.09612
33
21
0.79226
1.18839
1.58451
0.04952
0.07427
0.09903
34
22
0.81556
1.22334
1.63112
0.05097
0.07646
0.10194
35
23
0.83886
1.25829
1.67772
0.05243
0.07864
0.10486
36
24
0.86216
1.29324
1.72432
0.05389
0.08083
0.10777
37
25
0.88546
1.3282
1.77093
0.05534
0.08301
0.11068
38
26
0.90877
1.36315
1.81753
0.0568
0.0852
0.1136
39
27
0.93207
1.3981
1.86414
0.05825
0.08738
0.11651
40
28
0.95537
1.43305
1.91074
0.05971
0.08957
0.11942
41
29
0.97867
1.46801
1.95734
0.06117
0.09175
0.12233
42
2A
1.00197
1.50296
2.00395
0.06262
0.09393
0.12525
43
2B
1.02527
1.53791
2.05055
0.06408
0.09612
0.12816
44
2C
1.04858
1.57286
2.09715
0.06554
0.0983
0.13107
45
2D
1.07188
1.60782
2.14376
0.06699
0.10049
0.13398
13-8
MCF5307 User’s Manual
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Freescale Semiconductor, Inc.
Calculating Time-Out Values
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock) (Continued)
Freescale Semiconductor, Inc...
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
46
2E
1.09518
1.64277
2.19036
0.06845
0.10267
22.5 MHz
0.1369
47
2F
1.11848
1.67772
2.23696
0.06991
0.10486
0.13981
48
30
1.14178
1.71267
2.28357
0.07136
0.10704
0.14272
49
31
1.16508
1.74763
2.33017
0.07282
0.10923
0.14564
50
32
1.18839
1.78258
2.37677
0.07427
0.11141
0.14855
51
33
1.21169
1.81753
2.42338
0.07573
0.1136
0.15146
52
34
1.23499
1.85248
2.46998
0.07719
0.11578
0.15437
53
35
1.25829
1.88744
2.51658
0.07864
0.11796
0.15729
54
36
1.28159
1.92239
2.56319
0.0801
0.12015
0.1602
55
37
1.30489
1.95734
2.60979
0.08156
0.12233
0.16311
56
38
1.3282
1.99229
2.65639
0.08301
0.12452
0.16602
57
39
1.3515
2.02725
2.703
0.08447
0.1267
0.16894
58
3A
1.3748
2.0622
2.7496
0.08592
0.12889
0.17185
59
3B
1.3981
2.09715
2.7962
0.08738
0.13107
0.17476
60
3C
1.4214
2.1321
2.84281
0.08884
0.13326
0.17768
61
3D
1.4447
2.16706
2.88941
0.09029
0.13544
0.18059
62
3E
1.46801
2.20201
2.93601
0.09175
0.13763
0.1835
63
3F
1.49131
2.23696
2.98262
0.09321
0.13981
0.18641
64
40
1.51461
2.27191
3.02922
0.09466
0.14199
0.18933
65
41
1.53791
2.30687
3.07582
0.09612
0.14418
0.19224
66
42
1.56121
2.34182
3.12243
0.09758
0.14636
0.19515
67
43
1.58451
2.37677
3.16903
0.09903
0.14855
0.19806
68
44
1.60782
2.41172
3.21563
0.10049
0.15073
0.20098
69
45
1.63112
2.44668
3.26224
0.10194
0.15292
0.20389
70
46
1.65442
2.48163
3.30884
0.1034
0.1551
0.2068
71
47
1.67772
2.51658
3.35544
0.10486
0.15729
0.20972
72
48
1.70102
2.55153
3.40205
0.10631
0.15947
0.21263
73
49
1.72432
2.58649
3.44865
0.10777
0.16166
0.21554
74
4A
1.74763
2.62144
3.49525
0.10923
0.16384
0.21845
75
4B
1.77093
2.65639
3.54186
0.11068
0.16602
0.22137
76
4C
1.79423
2.69135
3.58846
0.11214
0.16821
0.22428
77
4D
1.81753
2.7263
3.63506
0.1136
0.17039
0.22719
78
4E
1.84083
2.76125
3.68167
0.11505
0.17258
0.2301
79
4F
1.86414
2.7962
3.72827
0.11651
0.17476
0.23302
80
50
1.88744
2.83116
3.77487
0.11796
0.17695
0.23593
81
51
1.91074
2.86611
3.82148
0.11942
0.17913
0.23884
82
52
1.93404
2.90106
3.86808
0.12088
0.18132
0.24176
83
53
1.95734
2.93601
3.91468
0.12233
0.1835
0.24467
84
54
1.98064
2.97097
3.96129
0.12379
0.18569
0.24758
85
55
2.00395
3.00592
4.00789
0.12525
0.18787
0.25049
Chapter 13. Timer Module
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13-9
Freescale Semiconductor, Inc.
Calculating Time-Out Values
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock) (Continued)
Freescale Semiconductor, Inc...
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
22.5 MHz
86
56
2.02725
3.04087
4.05449
0.1267
0.19005
0.25341
87
57
2.05055
3.07582
4.1011
0.12816
0.19224
0.25632
88
58
2.07385
3.11078
4.1477
0.12962
0.19442
0.25923
89
59
2.09715
3.14573
4.1943
0.13107
0.19661
0.26214
90
5A
2.12045
3.18068
4.24091
0.13253
0.19879
0.26506
91
5B
2.14376
3.21563
4.28751
0.13398
0.20098
0.26797
92
5C
2.16706
3.25059
4.33411
0.13544
0.20316
0.27088
93
5D
2.19036
3.28554
4.38072
0.1369
0.20535
0.27379
94
5E
2.21366
3.32049
4.42732
0.13835
0.20753
0.27671
95
5F
2.23696
3.35544
4.47392
0.13981
0.20972
0.27962
96
60
2.26026
3.3904
4.52053
0.14127
0.2119
0.28253
97
61
2.28357
3.42535
4.56713
0.14272
0.21408
0.28545
98
62
2.30687
3.4603
4.61373
0.14418
0.21627
0.28836
99
63
2.33017
3.49525
4.66034
0.14564
0.21845
0.29127
100
64
2.35347
3.53021
4.70694
0.14709
0.22064
0.29418
101
65
2.37677
3.56516
4.75354
0.14855
0.22282
0.2971
102
66
2.40007
3.60011
4.80015
0.15
0.22501
0.30001
103
67
2.42338
3.63506
4.84675
0.15146
0.22719
0.30292
104
68
2.44668
3.67002
4.89335
0.15292
0.22938
0.30583
105
69
2.46998
3.70497
4.93996
0.15437
0.23156
0.30875
106
6A
2.49328
3.73992
4.98656
0.15583
0.23375
0.31166
107
6B
2.51658
3.77487
5.03316
0.15729
0.23593
0.31457
108
6C
2.53988
3.80983
5.07977
0.15874
0.23811
0.31749
109
6D
2.56319
3.84478
5.12637
0.1602
0.2403
0.3204
110
6E
2.58649
3.87973
5.17297
0.16166
0.24248
0.32331
111
6F
2.60979
3.91468
5.21958
0.16311
0.24467
0.32622
112
70
2.63309
3.94964
5.26618
0.16457
0.24685
0.32914
113
71
2.65639
3.98459
5.31279
0.16602
0.24904
0.33205
114
72
2.67969
4.01954
5.35939
0.16748
0.25122
0.33496
115
73
2.703
4.05449
5.40599
0.16894
0.25341
0.33787
116
74
2.7263
4.08945
5.4526
0.17039
0.25559
0.34079
117
75
2.7496
4.1244
5.4992
0.17185
0.25777
0.3437
118
76
2.7729
4.15935
5.5458
0.17331
0.25996
0.34661
119
77
2.7962
4.1943
5.59241
0.17476
0.26214
0.34953
120
78
2.8195
4.22926
5.63901
0.17622
0.26433
0.35244
121
79
2.84281
4.26421
5.68561
0.17768
0.26651
0.35535
122
7A
2.86611
4.29916
5.73222
0.17913
0.2687
0.35826
123
7B
2.88941
4.33411
5.77882
0.18059
0.27088
0.36118
124
7C
2.91271
4.36907
5.82542
0.18204
0.27307
0.36409
125
7D
2.93601
4.40402
5.87203
0.1835
0.27525
0.367
13-10
MCF5307 User’s Manual
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Freescale Semiconductor, Inc.
Calculating Time-Out Values
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock) (Continued)
Freescale Semiconductor, Inc...
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
22.5 MHz
126
7E
2.95931
4.43897
5.91863
0.18496
0.27744
0.36991
127
7F
2.98262
4.47392
5.96523
0.18641
0.27962
0.37283
128
80
3.00592
4.50888
6.01184
0.18787
0.2818
0.37574
129
81
3.02922
4.54383
6.05844
0.18933
0.28399
0.37865
130
82
3.05252
4.57878
6.10504
0.19078
0.28617
0.38157
131
83
3.07582
4.61373
6.15165
0.19224
0.28836
0.38448
132
84
3.09912
4.64869
6.19825
0.1937
0.29054
0.38739
133
85
3.12243
4.68364
6.24485
0.19515
0.29273
0.3903
134
86
3.14573
4.71859
6.29146
0.19661
0.29491
0.39322
135
87
3.16903
4.75354
6.33806
0.19806
0.2971
0.39613
136
88
3.19233
4.7885
6.38466
0.19952
0.29928
0.39904
137
89
3.21563
4.82345
6.43127
0.20098
0.30147
0.40195
138
8A
3.23893
4.8584
6.47787
0.20243
0.30365
0.40487
139
8B
3.26224
4.89335
6.52447
0.20389
0.30583
0.40778
140
8C
3.28554
4.92831
6.57108
0.20535
0.30802
0.41069
141
8D
3.30884
4.96326
6.61768
0.2068
0.3102
0.4136
142
8E
3.33214
4.99821
6.66428
0.20826
0.31239
0.41652
143
8F
3.35544
5.03316
6.71089
0.20972
0.31457
0.41943
144
90
3.37874
5.06812
6.75749
0.21117
0.31676
0.42234
145
91
3.40205
5.10307
6.80409
0.21263
0.31894
0.42526
146
92
3.42535
5.13802
6.8507
0.21408
0.32113
0.42817
147
93
3.44865
5.17297
6.8973
0.21554
0.32331
0.43108
148
94
3.47195
5.20793
6.9439
0.217
0.3255
0.43399
149
95
3.49525
5.24288
6.99051
0.21845
0.32768
0.43691
150
96
3.51856
5.27783
7.03711
0.21991
0.32986
0.43982
151
97
3.54186
5.31279
7.08371
0.22137
0.33205
0.44273
152
98
3.56516
5.34774
7.13032
0.22282
0.33423
0.44564
153
99
3.58846
5.38269
7.17692
0.22428
0.33642
0.44856
154
9A
3.61176
5.41764
7.22352
0.22574
0.3386
0.45147
0.45438
155
9B
3.63506
5.4526
7.27013
0.22719
0.34079
156
9C
3.65837
5.48755
7.31673
0.22865
0.34297
0.4573
157
9D
3.68167
5.5225
7.36333
0.2301
0.34516
0.46021
158
9E
3.70497
5.55745
7.40994
0.23156
0.34734
0.46312
159
9F
3.72827
5.59241
7.45654
0.23302
0.34953
0.46603
160
A0
3.75157
5.62736
7.50314
0.23447
0.35171
0.46895
161
A1
3.77487
5.66231
7.54975
0.23593
0.35389
0.47186
162
A2
3.79818
5.69726
7.59635
0.23739
0.35608
0.47477
163
A3
3.82148
5.73222
7.64295
0.23884
0.35826
0.47768
164
A4
3.84478
5.76717
7.68956
0.2403
0.36045
0.4806
165
A5
3.86808
5.80212
7.73616
0.24176
0.36263
0.48351
Chapter 13. Timer Module
For More Information On This Product,
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13-11
Freescale Semiconductor, Inc.
Calculating Time-Out Values
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock) (Continued)
Freescale Semiconductor, Inc...
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
166
A6
3.89138
5.83707
7.78276
0.24321
0.36482
0.48642
167
A7
3.91468
5.87203
7.82937
0.24467
0.367
0.48934
168
A8
3.93799
5.90698
7.87597
0.24612
0.36919
0.49225
169
A9
3.96129
5.94193
7.92257
0.24758
0.37137
0.49516
170
AA
3.98459
5.97688
7.96918
0.24904
0.37356
0.49807
171
AB
4.00789
6.01184
8.01578
0.25049
0.37574
0.50099
172
AC
4.03119
6.04679
8.06238
0.25195
0.37792
0.5039
173
AD
4.05449
6.08174
8.10899
0.25341
0.38011
0.50681
174
AE
4.0778
6.11669
8.15559
0.25486
0.38229
0.50972
175
AF
4.1011
6.15165
8.20219
0.25632
0.38448
0.51264
176
B0
4.1244
6.1866
8.2488
0.25777
0.38666
0.51555
177
B1
4.1477
6.22155
8.2954
0.25923
0.38885
0.51846
178
B2
4.171
6.2565
8.342
0.26069
0.39103
0.52138
179
B3
4.1943
6.29146
8.38861
0.26214
0.39322
0.52429
180
B4
4.21761
6.32641
8.43521
0.2636
0.3954
0.5272
181
B5
4.24091
6.36136
8.48181
0.26506
0.39759
0.53011
182
B6
4.26421
6.39631
8.52842
0.26651
0.39977
0.53303
183
B7
4.28751
6.43127
8.57502
0.26797
0.40195
0.53594
184
B8
4.31081
6.46622
8.62162
0.26943
0.40414
0.53885
185
B9
4.33411
6.50117
8.66823
0.27088
0.40632
0.54176
186
BA
4.35742
6.53612
8.71483
0.27234
0.40851
0.54468
187
BB
4.38072
6.57108
8.76144
0.27379
0.41069
0.54759
188
BC
4.40402
6.60603
8.80804
0.27525
0.41288
0.5505
189
BD
4.42732
6.64098
8.85464
0.27671
0.41506
0.55342
190
BE
4.45062
6.67593
8.90125
0.27816
0.41725
0.55633
191
BF
4.47392
6.71089
8.94785
0.27962
0.41943
0.55924
192
C0
4.49723
6.74584
8.99445
0.28108
0.42161
0.56215
193
C1
4.52053
6.78079
9.04106
0.28253
0.4238
0.56507
194
C2
4.54383
6.81574
9.08766
0.28399
0.42598
0.56798
195
C3
4.56713
6.8507
9.13426
0.28545
0.42817
0.57089
196
C4
4.59043
6.88565
9.18087
0.2869
0.43035
0.5738
197
C5
4.61373
6.9206
9.22747
0.28836
0.43254
0.57672
198
C6
4.63704
6.95555
9.27407
0.28981
0.43472
0.57963
199
C7
4.66034
6.99051
9.32068
0.29127
0.43691
0.58254
200
C8
4.68364
7.02546
9.36728
0.29273
0.43909
0.58545
201
C9
4.70694
7.06041
9.41388
0.29418
0.44128
0.58837
202
CA
4.73024
7.09536
9.46049
0.29564
0.44346
0.59128
203
CB
4.75354
7.13032
9.50709
0.2971
0.44564
0.59419
204
CC
4.77685
7.16527
9.55369
0.29855
0.44783
0.59711
205
CD
4.80015
7.20022
9.6003
0.30001
0.45001
0.60002
13-12
MCF5307 User’s Manual
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22.5 MHz
Freescale Semiconductor, Inc.
Calculating Time-Out Values
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock) (Continued)
Freescale Semiconductor, Inc...
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
22.5 MHz
206
CE
4.82345
7.23517
9.6469
0.30147
0.4522
0.60293
207
CF
4.84675
7.27013
9.6935
0.30292
0.45438
0.60584
208
D0
4.87005
7.30508
9.74011
0.30438
0.45657
0.60876
209
D1
4.89335
7.34003
9.78671
0.30583
0.45875
0.61167
210
D2
4.91666
7.37498
9.83331
0.30729
0.46094
0.61458
211
D3
4.93996
7.40994
9.87992
0.30875
0.46312
0.61749
212
D4
4.96326
7.44489
9.92652
0.3102
0.46531
0.62041
213
D5
4.98656
7.47984
9.97312
0.31166
0.46749
0.62332
214
D6
5.00986
7.51479
10.01973
0.31312
0.46967
0.62623
215
D7
5.03316
7.54975
10.06633
0.31457
0.47186
0.62915
216
D8
5.05647
7.5847
10.11293
0.31603
0.47404
0.63206
217
D9
5.07977
7.61965
10.15954
0.31749
0.47623
0.63497
218
DA
5.10307
7.6546
10.20614
0.31894
0.47841
0.63788
219
DB
5.12637
7.68956
10.25274
0.3204
0.4806
0.6408
220
DC
5.14967
7.72451
10.29935
0.32185
0.48278
0.64371
221
DD
5.17297
7.75946
10.34595
0.32331
0.48497
0.64662
222
DE
5.19628
7.79441
10.39255
0.32477
0.48715
0.64953
223
DF
5.21958
7.82937
10.43916
0.32622
0.48934
0.65245
224
E0
5.24288
7.86432
10.48576
0.32768
0.49152
0.65536
225
E1
5.26618
7.89927
10.53236
0.32914
0.4937
0.65827
226
E2
5.28948
7.93423
10.57897
0.33059
0.49589
0.66119
227
E3
5.31279
7.96918
10.62557
0.33205
0.49807
0.6641
228
E4
5.33609
8.00413
10.67217
0.33351
0.50026
0.66701
229
E5
5.35939
8.03908
10.71878
0.33496
0.50244
0.66992
230
E6
5.38269
8.07404
10.76538
0.33642
0.50463
0.67284
231
E7
5.40599
8.10899
10.81198
0.33787
0.50681
0.67575
232
E8
5.42929
8.14394
10.85859
0.33933
0.509
0.67866
233
E9
5.4526
8.17889
10.90519
0.34079
0.51118
0.68157
234
EA
5.4759
8.21385
10.95179
0.34224
0.51337
0.68449
235
EB
5.4992
8.2488
10.9984
0.3437
0.51555
0.6874
236
EC
5.5225
8.28375
11.045
0.34516
0.51773
0.69031
237
ED
5.5458
8.3187
11.0916
0.34661
0.51992
0.69323
238
EE
5.5691
8.35366
11.13821
0.34807
0.5221
0.69614
239
EF
5.59241
8.38861
11.18481
0.34953
0.52429
0.69905
240
F0
5.61571
8.42356
11.23141
0.35098
0.52647
0.70196
241
F1
5.63901
8.45851
11.27802
0.35244
0.52866
0.70488
242
F2
5.66231
8.49347
11.32462
0.35389
0.53084
0.70779
243
F3
5.68561
8.52842
11.37122
0.35535
0.53303
0.7107
244
F4
5.70891
8.56337
11.41783
0.35681
0.53521
0.71361
245
F5
5.73222
8.59832
11.46443
0.35826
0.5374
0.71653
Chapter 13. Timer Module
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13-13
Freescale Semiconductor, Inc.
Calculating Time-Out Values
Table 13-5. Calculated Time-out Values (90-MHz Processor Clock) (Continued)
Freescale Semiconductor, Inc...
TMR[PS]
TMR[CLK] = 10 (System Bus Clock/16)
TMR[CLK] = 01 (System Bus Clock/1)
Decimal
Hex
45 MHz
30 MHz
22.5 MHz
45 MHz
30 MHz
22.5 MHz
246
F6
5.75552
8.63328
11.51103
0.35972
0.53958
0.71944
247
F7
5.77882
8.66823
11.55764
0.36118
0.54176
0.72235
248
F8
5.80212
8.70318
11.60424
0.36263
0.54395
0.72527
249
F9
5.82542
8.73813
11.65084
0.36409
0.54613
0.72818
250
FA
5.84872
8.77309
11.69745
0.36555
0.54832
0.73109
251
FB
5.87203
8.80804
11.74405
0.367
0.5505
0.734
252
FC
5.89533
8.84299
11.79065
0.36846
0.55269
0.73692
253
FD
5.91863
8.87794
11.83726
0.36991
0.55487
0.73983
254
FE
5.94193
8.9129
11.88386
0.37137
0.55706
0.74274
255
FF
5.96523
8.94785
11.93046
0.37283
0.55924
0.74565
13-14
MCF5307 User’s Manual
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Freescale Semiconductor, Inc.
Freescale Semiconductor, Inc...
Chapter 14
UART Modules
This chapter describes the use of the universal asynchronous/synchronous
receiver/transmitters (UARTs) implemented on the MCF5307 and includes programming
examples. All references to UART refer to one of these modules.
14.1 Overview
The MCF5307 contains two independent UARTs. Each UART can be clocked by BCLKO,
eliminating the need for an external crystal. As Figure 14-1 shows, each UART module
interfaces directly to the CPU and consists of the following:
•
•
•
•
Serial communication channel
Programmable transmitter and receiver clock generation
Internal channel control logic
Interrupt control logic
UART
Internal Channel
Control Logic
CTS
Serial
Communications
Channel
RTS
RxD
TxD
System Integration
Module (SIM)
Interrupt
Controller
Interrupt Control
Logic
Programmable
Clock
Generation
BCLKO
or
External clock (TIN)
Figure 14-1. Simplified Block Diagram
The serial communication channel provides a full-duplex asynchronous/synchronous
receiver and transmitter deriving an operating frequency from BCLKO or an external clock
using the timer pin. The transmitter converts parallel data from the CPU to a serial bit
stream, inserting appropriate start, stop, and parity bits. It outputs the resulting stream on
the channel transmitter serial data output (TxD). See Section 14.5.2.1, “Transmitting.”
The receiver converts serial data from the channel receiver serial data input (RxD) to
parallel format, checks for a start, stop, and parity bits, or break conditions, and transfers
the assembled character onto the bus during read operations. The receiver may be polledor interrupt-driven. See Section 14.5.2.2, “Receiver.”
Chapter 14. UART Modules
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14-1
Serial Module Overview
Freescale Semiconductor, Inc.
14.2 Serial Module Overview
The MCF5307 contains two independent UART modules, whose features are as follows:
Freescale Semiconductor, Inc...
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Each can be clocked by BCLKO, eliminating a need for an external crystal
Full-duplex asynchronous/synchronous receiver/transmitter channel
Quadruple-buffered receiver
Double-buffered transmitter
Independently programmable receiver and transmitter clock sources
Programmable data format:
— 5–8 data bits plus parity
— Odd, even, no parity, or force parity
— One, one-and-a-half, or two stop bits
Each channel programmable to normal (full-duplex), automatic echo, local
loop-back, or remote loop-back mode
Automatic wake-up mode for multidrop applications
Four maskable interrupt conditions
UART0 and UART1 have interrupt capability to DMA channels 2 and 3,
respectively, when either the RxRDY or FFULL bit is set in the USR.
Parity, framing, and overrun error detection
False-start bit detection
Line-break detection and generation
Detection of breaks originating in the middle of a character
Start/end break interrupt/status
14.3 Register Descriptions
This section contains a detailed description of each register and its specific function.
Flowcharts in Section 14.5.6, “Programming,” describe basic UART module programming.
The operation of the UART module is controlled by writing control bytes into the
appropriate registers. Table 14-1 is a memory map for UART module registers.
14-2
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Register Descriptions
Table 14-1. UART Module Programming Model
MBAR Offset
Freescale Semiconductor, Inc...
[31:24]
[23:16]
UART0
UART1
0x1C0
0x200
UART mode
registers1—(UMR1n)
[p. 14-4], (UMR2n) [p.
14-6]
—
0x1C4
0x204
(Read) UART status
registers—(USRn) [p.
14-7]
—
(Write) UART
clock-select
register1—(UCSRn)
[p. 14-8]
—
0x1C8
0x1CC
0x1D0
0x208
0x20C
0x210
[15:8]
[7:0]
(Read) Do not access2 —
(Write) UART
command
registers—(UCRn) [p.
14-9]
—
(UART/Read) UART
receiver
buffers—(URBn) [p.
14-11]
—
(UART/Write) UART
transmitter
buffers—(UTBn) [p.
14-11]
—
(Read) UART input
port change
registers—(UIPCRn)
[p. 14-12]
—
(Write) UART auxiliary —
control
registers1—(UACRn)
[p. 14-12]
0x1D4
0x214
(Read) UART interrupt —
status
registers—(UISRn) [p.
14-13]
(Write) UART interrupt —
mask
registers—(UIMRn) [p.
14-13]
0x1D8
0x218
UART divider upper
registers—(UDUn) [p.
14-14]
—
0x1DC
0x21C
UART divider lower
registers—(UDLn) [p.
14-14]
—
Chapter 14. UART Modules
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14-3
Register Descriptions
Freescale Semiconductor, Inc.
Table 14-1. UART Module Programming Model (Continued)
MBAR Offset
[31:24]
[23:16]
UART0
UART1
0x1E0–
0x1EC
0x220– Do not access2
0x22C
—
0x1F0
0x230
UART interrupt vector
register—(UIVRn) [p.
14-15]
—
0x1F4
0x234
(Read) UART input
port registers—(UIPn)
[p. 14-15]
—
[15:8]
[7:0]
Freescale Semiconductor, Inc...
(Write) Do not access2 —
0x1F8
0x238
(Read) Do not access2 —
(Write) UART output
port bit set command
registers—(UOP1n3)
[p. 14-15]
0x1FC
0x23C
—
(Read) Do not access2 —
(Write) UART output
port bit reset
command
registers—(UOP0n3)
[p. 14-15]
—
1
UMR1n, UMR2n, and UCSRn should be changed only after the receiver/transmitter is issued a software reset
command. That is, if channel operation is not disabled, undesirable results may occur.
2 This address is for factory testing. Reading this location results in undesired effects and possible incorrect
transmission or reception of characters. Register contents may also be changed.
3 Address-triggered commands
NOTE:
UART registers are accessible only as bytes. Although external
masters cannot access on-chip memories or MBAR, they can
access any UART registers.
14.3.1 UART Mode Registers 1 (UMR1n)
The UART mode registers 1 (UMR1n) control configuration. UMR1n can be read or
written when the mode register pointer points to it, at RESET or after a RESET MODE
REGISTER POINTER command using UCRn[MISC]. After UMR1n is read or written, the
pointer points to UMR2n.
14-4
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Field
7
6
5
RxRTS
RxIRQ/FFULL
ERR
Reset
4
2
1
PT
0
B/C
0000_0000
R/W
Address
3
PM
Register Descriptions
R/W
MBAR + 0x1C0 (UART0), 0x200 (UART1). After UMR1n is read or written, the pointer points to UMR2n.
Figure 14-2. UART Mode Registers 1 (UMR1n)
Table 14-2 describes UMR1n fields.
Table 14-2. UMR1n Field Descriptions
Bits
Freescale Semiconductor, Inc...
Name
Description
7
RxRTS
Receiver request-to-send. Allows the RTS output to control the CTS input of the transmitting device
to prevent receiver overrun. If both the receiver and transmitter are incorrectly programmed for RTS
control, RTS control is disabled for both. Transmitter RTS control is configured in UMR2n[TxRTS].
0 The receiver has no effect on RTS.
1 When a valid start bit is received, RTS is negated if the UART's FIFO is full. RTS is reasserted
when the FIFO has an empty position available.
6
RxIRQ/
FFULL
Receiver interrupt select.
0 RxRDY is the source that generates IRQ.
1 FFULL is the source that generates IRQ.
5
ERR
Error mode. Configures the FIFO status bits, USRn[RB,FE,PE].
0 Character mode. The USRn values reflect the status of the character at the top of the FIFO. ERR
must be 0 for correct A/D flag information when in multidrop mode.
1 Block mode. The USRn values are the logical OR of the status for all characters reaching the top of
the FIFO because the last RESET ERROR STATUS command for the channel was issued. See
Section 14.3.5, “UART Command Registers (UCRn).”
4–3
PM
Parity mode. Selects the parity or multidrop mode for the channel. The parity bit is added to the
transmitted character, and the receiver performs a parity check on incoming data. The value of PM
affects PT, as shown below.
2
PT
Parity type. PM and PT together select parity type (PM = 0x) or determine whether a data or address
character is transmitted (PM = 11).
PM
1–0
B/C
Parity Mode
Parity Type (PT= 0)
00
With parity
Even parity
01
Force parity
Low parity
10
No parity
11
Multidrop mode
Parity Type (PT= 1)
Odd parity
High parity
n/a
Data character
Address character
Bits per character. Select the number of data bits per character to be sent. The values shown do not
include start, parity, or stop bits.
00 5 bits
01 6 bits
10 7 bits
11 8 bits
Chapter 14. UART Modules
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14-5
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Register Descriptions
14.3.2 UART Mode Register 2 (UMR2n)
UART mode registers 2 (UMR2n) control UART module configuration. UMR2n can be
read or written when the mode register pointer points to it, which occurs after any access to
UMR1n. UMR2n accesses do not update the pointer.
7
Field
6
CM
5
4
TxRTS
TxCTS
Reset
Freescale Semiconductor, Inc...
0
SB
0000_0000
R/W
Address
3
R/W
MBAR + 0x1C0, 0x200. After UMR1n is read or written, the pointer points to UMR2n.
Figure 14-3. UART Mode Register 2 (UMR2n)
Table 14-3 describes UMR2n fields.
Table 14-3. UMR2n Field Descriptions
Bits
Name
7–6
CM
Description
Channel mode. Selects a channel mode. Section 14.5.3, “Looping Modes,” describes individual
modes.
00 Normal
01 Automatic echo
10 Local loop-back
11 Remote loop-back
5
TxRTS Transmitter ready-to-send. Controls negation of RTS to automatically terminate a message
transmission. Attempting to program a receiver and transmitter in the same channel for RTS control is
not permitted and disables RTS control for both.
0 The transmitter has no effect on RTS.
1 In applications where the transmitter is disabled after transmission completes, setting this bit
automatically clears UOP[RTS] one bit time after any characters in the channel transmitter shift and
holding registers are completely sent, including the programmed number of stop bits.
4
TxCTS Transmitter clear-to-send. If both TxCTS and TxRTS are enabled, TxCTS controls the operation of the
transmitter.
0 CTS has no effect on the transmitter.
1 Enables clear-to-send operation. The transmitter checks the state of CTS each time it is ready to
send a character. If CTS is asserted, the character is sent; if it is negated, the channel TxD remains
in the high state and transmission is delayed until CTS is asserted. Changes in CTS as a character is
being sent do not affect its transmission.
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Register Descriptions
Freescale Semiconductor, Inc...
Table 14-3. UMR2n Field Descriptions (Continued)
Bits
Name
Description
3–0
SB
Stop-bit length control. Selects the length of the stop bit appended to the transmitted character.
Stop-bit lengths of 9/16th to 2 bits are programmable for 6–8 bit characters. Lengths of 1 1/16th to 2
bits are programmable for 5-bit characters. In all cases, the receiver checks only for a high condition at
the center of the first stop-bit position, that is, one bit time after the last data bit or after the parity bit, if
parity is enabled. If an external 1x clock is used for the transmitter, clearing bit 3 selects one stop bit
and setting bit 3 selects 2 stop bits for transmission.
SB
5 Bits
6–8 Bits
SB
5 Bits
6–8 Bits
SB
5–8 Bits
SB
5–8 Bits
0000
1.063
0.563
0100
1.313
0.813
1000
1.563
1100
1.813
0001
1.125
0.625
0101
1.375
0.875
1001
1.625
1101
1.875
0010
1.188
0.688
0110
1.438
0.938
1010
1.688
1110
1.938
0011
1.250
0.750
0111
1.500
1.000
1011
1.750
1111
2.000
14.3.3 UART Status Registers (USRn)
The USRn, Figure 14-4, shows status of the transmitter, the receiver, and the FIFO.
Field
7
6
5
4
3
2
1
0
RB
FE
PE
OE
TxEMP
TxRDY
FFULL
RxRDY
Reset
0000_0000
R/W
Read only
Address
MBAR + 0x1C4 (USR0), 0x204 (USR1)
Figure 14-4. UART Status Register (USRn)
Table 14-4 describes USRn fields.
Table 14-4. USRn Field Descriptions
Bits
Name
Description
7
RB
Received break. The received break circuit detects breaks that originate in the middle of a received
character. However, a break in the middle of a character must persist until the end of the next
detected character time.
0 No break was received.
1 An all-zero character of the programmed length was received without a stop bit. RB is valid only
when RxRDY = 1. Only a single FIFO position is occupied when a break is received. Further
entries to the FIFO are inhibited until RxD returns to the high state for at least one-half bit time,
which is equal to two successive edges of the UART clock.
6
FE
Framing error.
0 No framing error occurred.
1 No stop bit was detected when the corresponding data character in the FIFO was received. The
stop-bit check occurs in the middle of the first stop-bit position. FE is valid only when RxRDY = 1.
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Register Descriptions
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Freescale Semiconductor, Inc...
Table 14-4. USRn Field Descriptions (Continued)
Bits
Name
Description
5
PE
Parity error. Valid only if RxRDY = 1.
0 No parity error occurred.
1 If UMR1n[PM] = 0x (with parity or force parity), the corresponding character in the FIFO was
received with incorrect parity. If UMR1n[PM] = 11 (multidrop), PE stores the received A/D bit.
4
OE
Overrun error. Indicates whether an overrun occurs.
0 No overrun occurred.
1 One or more characters in the received data stream have been lost. OE is set upon receipt of a
new character when the FIFO is full and a character is already in the shift register waiting for an
empty FIFO position. When this occurs, the character in the receiver shift register and its break
detect, framing error status, and parity error, if any, are lost. OE is cleared by the RESET ERROR
STATUS command in UCRn.
3
TxEMP Transmitter empty.
0 The transmitter buffer is not empty. Either a character is being shifted out, or the transmitter is
disabled. The transmitter is enabled/disabled by programming UCRn[TC].
1 The transmitter has underrun (both the transmitter holding register and transmitter shift registers
are empty). This bit is set after transmission of the last stop bit of a character if there are no
characters in the transmitter holding register awaiting transmission.
2
TxRDY
Transmitter ready.
0 The CPU loaded the transmitter holding register or the transmitter is disabled.
1 The transmitter holding register is empty and ready for a character. TxRDY is set when a
character is sent to the transmitter shift register and when the transmitter is first enabled. If the
transmitter is disabled, characters loaded into the transmitter holding register are not sent.
1
FFULL
FIFO full.
0 The FIFO is not full but may hold up to two unread characters.
1 A character was received and is waiting in the receiver buffer FIFO.
0
RxRDY Receiver ready
0 The CPU has read the receiver buffer and no characters remain in the FIFO after this read.
1 One or more characters were received and are waiting in the receiver buffer FIFO.
14.3.4 UART Clock-Select Registers (UCSRn)
The UART clock-select registers (UCSRn) select an external clock on the TIN input
(divided by 1 or 16) or a prescaled BCLKO as the clocking source for the transmitter and
receiver. See Section 14.5.1, “Transmitter/Receiver Clock Source.” The transmitter and
receiver can use different clock sources. To use BCLKO for both, set UCSRn to 0xDD.
7
Field
Reset
R/W
Address
4
3
RCS
0
TCS
0000_0000
Write only
MBAR + 0x1C4 (UCSR0), 0x204 (UCSR1)
Figure 14-5. UART Clock-Select Register (UCSRn)
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Register Descriptions
Table 14-5 describes UCSRn fields.
Freescale Semiconductor, Inc...
Table 14-5. UCSRn Field Descriptions
Bits
Name
7–4
RCS
Receiver clock select. Selects the clock source for the receiver channel.
1101 Prescaled BCLKO
1110 TIN divided by 16
1111 TIN
Description
3–0
TCS
Transmitter clock select. Selects the clock source for the transmitter channel.
1101 Prescaled BCLKO
1110 TIN divided by 16
1111 TIN
14.3.5 UART Command Registers (UCRn)
The UART command registers (UCRn), Figure 14-6, supply commands to the UART. Only
multiple commands that do not conflict can be specified in a single write to a UCRn. For
example, RESET TRANSMITTER and ENABLE TRANSMITTER cannot be specified in one
command.
7
Field
—
Reset
6
4
3
MISC
2
1
TC
0
RC
0000_0000
R/W
Write only
Address
MBAR + 0x1C8, 0x208
Figure 14-6. UART Command Register (UCRn)
Table 14-6 describes UCRn fields and commands. Examples in Section 14.5.2,
“Transmitter and Receiver Operating Modes,” show how these commands are used.
Table 14-6. UCRn Field Descriptions
Bits
7
Value
Command
—
—
Description
Reserved, should be cleared.
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Register Descriptions
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Table 14-6. UCRn Field Descriptions (Continued)
Bits
Value
Command
Description
6–4
MISC Field (This field selects a single command.)
000
NO COMMAND
—
001
RESET MODE
Causes the mode register pointer to point to UMR1n.
REGISTER POINTER
010
RESET RECEIVER
Immediately disables the receiver, clears USRn[FFULL,RxRDY], and reinitializes
the receiver FIFO pointer. No other registers are altered. Because it places the
receiver in a known state, use this command instead of RECEIVER DISABLE when
reconfiguring the receiver.
011
RESET
disables the transmitter and clears USRn[TxEMP,TxRDY]. No other registers
are altered. Because it places the transmitter in a known state, use this
command instead of TRANSMITTER DISABLE when reconfiguring the transmitter.
Freescale Semiconductor, Inc...
TRANSMITTER
100
101
STATUS
lears USRn[RB,FE,PE,OE]. Also used in block mode to clear all error bits after a
data block is received.
RESET BREAK–
Clears the delta break bit, UISRn[DB].
RESET ERROR
CHANGE INTERRUPT
110
START BREAK
Forces TxD low. If the transmitter is empty, the break may be delayed up to one
bit time. If the transmitter is active, the break starts when character transmission
completes. The break is delayed until any character in the transmitter shift
register is sent. Any character in the transmitter holding register is sent after the
break. The transmitter must be enabled for the command to be accepted. This
command ignores the state of CTS.
111
STOP BREAK
Causes TxD to go high (mark) within two bit times. Any characters in the
transmitter buffer are sent.
3–2
TC Field (This field selects a single command)
00
NO ACTION TAKEN
Causes the transmitter to stay in its current mode: if the transmitter is enabled, it
remains enabled; if the transmitter is disabled, it remains disabled.
01
TRANSMITTER
Enables operation of the channel’s transmitter. USRn[TxEMP,TxRDY] are set. If
the transmitter is already enabled, this command has no effect.
ENABLE
10
TRANSMITTER
DISABLE
11
14-10
—
Terminates transmitter operation and clears USRn[TxEMP,TxRDY]. If a character
is being sent when the transmitter is disabled, transmission completes before the
transmitter becomes inactive. If the transmitter is already disabled, the command
has no effect.
Reserved, do not use.
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Register Descriptions
Table 14-6. UCRn Field Descriptions (Continued)
Bits
Value
Command
Freescale Semiconductor, Inc...
1–0
Description
RC (This field selects a single command)
00
NO ACTION TAKEN
Causes the receiver to stay in its current mode. If the receiver is enabled, it
remains enabled; if disabled, it remains disabled.
01
RECEIVER ENABLE
If the UART module is not in multidrop mode (UMR1n[PM] ≠ 11), RECEIVER
ENABLE enables the channel's receiver and forces it into search-for-start-bit state.
If the receiver is already enabled, this command has no effect.
10
RECEIVER DISABLE
Disables the receiver immediately. Any character being received is lost. The
command does not affect receiver status bits or other control registers. If the
UART module is programmed for local loop-back or multidrop mode, the receiver
operates even though this command is selected. If the receiver is already
disabled, the command has no effect.
11
—
Reserved, do not use.
14.3.6 UART Receiver Buffers (URBn)
The receiver buffers contain one serial shift register and three receiver holding registers,
which act as a FIFO. RxD is connected to the serial shift register. The CPU reads from the
top of the stack while the receiver shifts and updates from the bottom when the shift register
is full (see Figure 14-20). RB contains the character in the receiver.
7
0
Field
RB
Reset
0000_0000
R/W
Read only
Address
MBAR + 0x1CC,0x20C
Figure 14-7. UART Receiver Buffer (URB0)
14.3.7 UART Transmitter Buffers (UTBn)
The transmitter buffers consist of the transmitter holding register and the transmitter shift
register. The holding register accepts characters from the bus master if channel’s
USRn[TxRDY] is set. A write to the transmitter buffer clears TxRDY, inhibiting any more
characters until the shift register can accept more data. When the shift register is empty, it
checks if the holding register has a valid character to be sent (TxRDY = 0). If there is a valid
character, the shift register loads it and sets USRn[TxRDY] again. Writes to the transmitter
buffer when the channel’s TxRDY = 0 and when the transmitter is disabled have no effect
on the transmitter buffer.
Figure 14-8 shows UTB0. TB contains the character in the transmitter buffer.
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14-11
Register Descriptions
Freescale Semiconductor, Inc.
7
0
Field
TB
Reset
0000_0000
R/W
Write only
Address
MBAR + 0x1CC,0x20C
Figure 14-8. UART Transmitter Buffer (UTB0)
14.3.8 UART Input Port Change Registers (UIPCRn)
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The input port change registers (UIPCRn), Figure 14-9, hold the current state and the
change-of-state for CTS.
7
Field
Reset
5
—
3
1
111
0000
0
R/W
Address
4
COS
0
CTS
11
CTS
Read only
MBAR + 0x1D0 (UIPCR0), 0x210 (UIPCR1)
Figure 14-9. UART Input Port Change Register (UIPCRn)
Table 14-7 describes UIPCRn fields.
Table 14-7. UIPCRn Field Descriptions
Bits Name
7–5
—
4
COS
3–1
—
0
CTS
Description
Reserved, should be cleared.
Change of state (high-to-low or low-to-high transition).
0 No change-of-state since the CPU last read UIPCRn. Reading UIPCRn clears UISRn[COS].
1 A change-of-state longer than 25–50 µs occurred on the CTS input. UACRn can be programmed to
generate an interrupt to the CPU when a change of state is detected.
Reserved, should be cleared.
Current state. Starting two serial clock periods after reset, CTS reflects the state of CTS. If CTS is
detected asserted at that time, COS is set, which initiates an interrupt if UACRn[IEC] is enabled.
0 The current state of the CTS input is asserted.
1 The current state of the CTS input is negated.
14.3.9 UART Auxiliary Control Register (UACRn)
The UART auxiliary control registers (UACRn), Figure 14-7, control the input enable.
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Register Descriptions
7
1
Field
—
Reset
0
IEC
0000_0000
R/W
Write only
Address
MBAR + 0x1D0 (UACR0), 0x210 (UACR1)
Figure 14-10. UART Auxiliary Control Register (UACRn)
Table 14-8 describes UACRn fields.
Freescale Semiconductor, Inc...
Table 14-8. UACRn Field Descriptions
Bits
Name
7–1
—
0
IEC
Description
Reserved, should be cleared.
Input enable control.
0 Setting the corresponding UIPCRn bit has no effect on UISRn[COS].
1 UISRn[COS] is set and an interrupt is generated when the UIPCRn[COS] is set by an external
transition on the CTS input (if UIMRn[COS] = 1).
14.3.10 UART Interrupt Status/Mask Registers
(UISRn/UIMRn)
The UART interrupt status registers (UISRn), Figure 14-11, provide status for all potential
interrupt sources. UISRn contents are masked by UIMRn. If corresponding UISRn and
UIMRn bits are set, the internal interrupt output is asserted. If a UIMRn bit is cleared, the
state of the corresponding UISRn bit has no effect on the output.
NOTE:
True status is provided in the UISRn regardless of UIMRn
settings. UISRn is cleared when the UART module is reset.
7
Field
Reset
R/W
Address
COS
6
3
—
2
1
0
DB
FFULL/RxRDY
TxRDY
0000_0000
Read only for status, write only for mask.
MBAR + 0x1D4 (UISR0), 0x214 (UISR1); MBAR + 0x1D4 (UIMR0), 0x214 (UIMR1)
Figure 14-11. UART Interrupt Status/Mask Registers (UISRn/UIMRn)
Table 14-9 describes UISRn and UIMRn fields.
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Register Descriptions
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Table 14-9. UISRn/UIMRn Field Descriptions
Bits
Freescale Semiconductor, Inc...
7
Name
Description
COS
Change-of-state.
0 UIPCRn[COS] is not selected.
1 Change-of-state occurred on CTS and was programmed in UACRn[IEC] to cause an interrupt.
6–3
—
Reserved, should be cleared.
2
DB
Delta break.
0 No new break-change condition to report. Section 14.3.5, “UART Command Registers (UCRn),”
describes the RESET BREAK-CHANGE INTERRUPT command.
1 The receiver detected the beginning or end of a received break.
1
FFULL/ RxRDY (receiver ready) if UMR1n[FFULL/RxRDY] = 0; FIFO full (FFULL) if UMR1n[FFULL/RxRDY]
RxRDY = 1. Duplicate of USRn[FFULL/RxRDY]. If FFULL is enabled for UART0 or UART1, DMA channels 2
or 3 are respectively interrupted when the FIFO is full.
0
TxRDY
Transmitter ready. This bit is the duplication of USRn[TxRDY].
0 The transmitter holding register was loaded by the CPU or the transmitter is disabled. Characters
loaded into the transmitter holding register when TxRDY = 0 are not sent.
1 The transmitter holding register is empty and ready to be loaded with a character.
14.3.11 UART Divider Upper/Lower Registers (UDUn/UDLn)
The UDUn registers (formerly called UBG1n) holds the MSB, and the UDLn registers
(formerly UBG2n) hold the LSB of the preload value. UDUn and UDLn concatenate to
provide a divider to BCLKO for transmitter/receiver operation, as described in
Section 14.5.1.2.1, “BCLKO Baud Rates.”
7
0
Field
Divider MSB
Reset
0000_0000
R/W
R/W
Address
MBAR + 0x1D8 (UDU0), 0x218 (UDU1)
Figure 14-12. UART Divider Upper Register (UDUn)
7
0
Field
Divider LSB
Reset
0000_0000
R/W
Address
R/W
MBAR + 0x1DC (UDL0), 0x21C (UDL1)
Figure 14-13. UART Divider Lower Register (UDLn)
NOTE:
The minimum value that can be loaded on the concatenation of
UDUn with UDLn is 0x0002. Both UDUn and UDLn are
write-only and cannot be read by the CPU.
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Register Descriptions
14.3.12 UART Interrupt Vector Register (UIVRn)
The UIVRn, Figure 14-14, contain the 8-bit internal interrupt vector number (IVR).
7
0
Field
IVR
Reset
0000_1111
R/W
R/W
Address
MBAR + 0x1F0 (UIVR0), 0x230 (UIVR1)
Figure 14-14. UART Interrupt Vector Register (UIVRn)
Freescale Semiconductor, Inc...
Table 14-10 describes UIVRn fields.
Table 14-10. UIVRn Field Descriptions
Bits
Name
Description
7–0
IVR
Interrupt vector. Indicates the vector number where the address of the exception handler for the
specified interrupt is located. UIVRn is reset to 0x0F, indicating an uninitialized interrupt condition.
14.3.13 UART Input Port Register (UIPn)
The UART input port registers (UIPn), Figure 14-15, show the current state of the CTS
input.
7
1
Field
—
Reset
1111_1111
R/W
Read only
Address
0
CTS
MBAR + 0x1F4 (UIP0), 0x234 (UIP1)
Figure 14-15. UART Input Port Register (UIPn)
Table 14-11 describes UIPn fields.
Table 14-11. UIPn Field Descriptions
Bits
Name
7–1
—
0
CTS
Description
Reserved, should be cleared.
Current state. The CTS value is latched and reflects the state of the input pin when UIPn is read.
Note: This bit has the same function and value as UIPCRn[RTS].
0 The current state of the CTS input is logic 0.
1 The current state of the CTS input is logic 1.
14.3.14 UART Output Port Command Registers
(UOP1n/UOP0n)
In UART mode, the RTS output can be asserted by writing a 1 to UOP1n[RTS] and negated
by writing a 1 to UOP0n[RTS]. See Figure 14-16.
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UART Module Signal Definitions
7
1
Field
—
Reset
0
RTS
0000_0000
R/W
Write only
Addr
UART0: MBAR + 0x1F8 (UOP1), 0x1FC (UOP0); UART1 0x238 (UOP1), 0x23C (UOP0)
Figure 14-16. UART Output Port Command Register (UOP1/UOP0)
Table 14-12 describes UOP1 fields.
Table 14-12. UOP1/UOP0 Field Descriptions
Freescale Semiconductor, Inc...
Bits
Name
Description
7–1
—
Reserved, should be cleared.
0
RTS
Output port parallel output. Controls assertion (UOP1)/negation (UOP0) of RTS output.
0 Not affected.
1 Asserts RTS (UOP1). Negates RTS (UOP0).
14.4 UART Module Signal Definitions
Figure 14-17 shows both the external and internal signal groups.
BCLKO
or
External Clock (TIN)
Clock Source
Generator
UART Module
Internal Bus
Output Port
RTS
Input Port
CTS
Four-Character
Receive Buffer
RxD
Two-Character
Transmit Buffer
TxD
Control
Interface
to CPU
Address Bus
Internal
Control
Logic
Data
To Interrupt
Controller
(SIM)
External
Interface
Signals
IRQ
Figure 14-17. UART Block Diagram Showing External and Internal Interface Signals
An internal interrupt request signal (IRQ) is provided to notify the interrupt controller of an
interrupt condition. The output is the logical NOR of unmasked UISRn bits. The interrupt
level of a UART module is programmed in the interrupt controller in the system integration
module (SIM). The UART can use the autovector for the programmed interrupt level or
supply the vector from the UIVRn when the UART interrupt is acknowledged.
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UART Module Signal Definitions
The interrupt level, priority, and auto-vectoring capability is programmed in SIM register
ICR4 for UART0 and ICR5 for UART1. See Section 9.2.1, “Interrupt Control Registers
(ICR0–ICR9).”
Note that the UARTs can also automatically transfer data by using the DMA rather than
interrupting the core. When UIMR[FFULL] is 1 and a receiver’s FIFO is full, it can send
an interrupt to a DMA channel so the FIFO data can be transferred to memory. Note also
that UART0 and UART1’s interrupt requests are connected to DMA channel 2 and
channel 3, respectively.
Freescale Semiconductor, Inc...
Table 14-13 briefly describes the UART module signals.
NOTE:
The terms ‘assertion’ and ‘negation’ are used to avoid
confusion between active-low and active-high signals.
‘Asserted’ indicates that a signal is active, independent of the
voltage level; ‘negated’ indicates that a signal is inactive.
Table 14-13. UART Module Signals
Signal
Description
Transmitter
Serial Data
Output (TxD)
TxD is held high (mark condition) when the transmitter is disabled, idle, or operating in the local
loop-back mode. Data is shifted out on TxD on the falling edge of the clock source, with the least
significant bit (lsb) sent first.
Receiver
Serial Data
Input (RxD)
Data received on RxD is sampled on the rising edge of the clock source, with the lsb received first.
Clear-toSend (CTS)
This input can generate an interrupt on a change of state.
Request-toSend (RTS)
This output can be programmed to be negated or asserted automatically by either the receiver or the
transmitter. When connected to a transmitter’s CTS, RTS can control serial data flow.
Figure 14-18 shows a signal configuration for a UART/RS-232 interface.
UART
RS-232 Transceiver
RTS
DI2
CTS
DO2
TxD
DI1
RxD
DO1
Figure 14-18. UART/RS-232 Interface
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Operation
14.5 Operation
This section describes operation of the clock source generator, transmitter, and receiver.
14.5.1 Transmitter/Receiver Clock Source
BCLKO serves as the basic timing reference for the clock source generator logic, which
consists of a clock generator and a programmable 16-bit divider dedicated to the UART.
The clock generator cannot produce standard baud rates if BCLKO is used, so the 16-bit
divider should be used.
Freescale Semiconductor, Inc...
14.5.1.1 Programmable Divider
As Figure 14-19 shows, the UART transmitter and receiver can use the following clock
sources:
•
•
An external clock signal on the TIN pin that can be divided by 16. When not divided,
TIN provides a synchronous clock mode; when divided by 16, it is asynchronous.
BCLKO supplies an asynchronous clock source that is divided by 32 and then
divided by the 16-bit value programmed in UDUn and UDLn. See Section 14.3.11,
“UART Divider Upper/Lower Registers (UDUn/UDLn).”
The choice of TIN or BCLKO is programmed in the UCSR.
TOUT
On-Chip
Timer Module
TIN
UART
Clocking sources programmed in UCSR
TxD
Tx Buffer
x1
Prescaler
TIN
x16
Prescaler
TIN
Tx
Rx
Clock
Generator
RxD
16-Bit
Divider
x32
Prescaler
Rx Buffer
BCLKO
Figure 14-19. Clocking Source Diagram
NOTE:
If TIN is a clocking source for either the timer or UART, the
timer module cannot use TIN for timer capture.
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Operation
14.5.1.2 Calculating Baud Rates
The following sections describe how to calculate baud rates.
14.5.1.2.1 BCLKO Baud Rates
When BCLKO is the UART clocking source, it goes through a divide-by-32 prescaler and
then passes through the 16-bit divider of the concatenated UDUn and UDLn registers.
Using a 45-MHz BCLKO, the baud-rate calculation is as follows:
45MHz
Baudrate = -----------------------------------[ 32 × divider ]
Freescale Semiconductor, Inc...
let baud rate = 9600, then
45MHz
Divider = ----------------------------- = 146 ( decimal ) = 0092 ( hexadecimal )
[ 32 × 9600 ]
therefore UDU = 0x00 and UDL = 0x92.
14.5.1.2.2 External Clock
An external source clock (TIN) can be used as is or divided by 16.
Externalclockfrequency
Baudrate = --------------------------------------------------------------------16or1
14.5.2 Transmitter and Receiver Operating Modes
Figure 14-20 is a functional block diagram of the transmitter and receiver showing the
command and operating registers, which are described generally in the following sections
and described in detail in Section 14.3, “Register Descriptions.”
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Operation
UART0
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UART Command Register (UCR0)
UART
Transmitter Buffer
(UTB0)
(2 Registers)
W
UART Mode Register 1 (UMR1)
R/W
UART Mode Register 2 (UMR2)
R/W
UART Status Register (USR0)
R
Transmitter Holding Register
W
External
Interface
TXD
Transmitter Shift Register
Receiver Holding Register 1
R
FIFO
Receiver Holding Register 2
Receiver Holding Register 3
UART Receive
Buffer (URB0)
(4 Registers)
Receiver Shift Register
Figure 14-20. Transmitter and Receiver Functional Diagram
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RXD
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Operation
14.5.2.1 Transmitting
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The transmitter is enabled through the UART command register (UCRn). When it is ready
to accept a character, the UART sets USRn[TxRDY]. The transmitter converts parallel data
from the CPU to a serial bit stream on TxD. It automatically sends a start bit followed by
the programmed number of data bits, an optional parity bit, and the programmed number
of stop bits. The lsb is sent first. Data is shifted from the transmitter output on the falling
edge of the clock source.
After the stop bits are sent, if no new character is in the transmitter holding register, the TxD
output remains high (mark condition) and the transmitter empty bit, USRn[TxEMP], is set.
Transmission resumes and TxEMP is cleared when the CPU loads a new character into the
UART transmitter buffer (UTBn). If the transmitter receives a disable command, it
continues until any character in the transmitter shift register is completely sent.
If the transmitter is reset through a software command, operation stops immediately (see
Section 14.3.5, “UART Command Registers (UCRn)”). The transmitter is reenabled
through the UCRn to resume operation after a disable or software reset.
If the clear-to-send operation is enabled, CTS must be asserted for the character to be
transmitted. If CTS is negated in the middle of a transmission, the character in the shift
register is sent and TxD remains in mark state until CTS is reasserted. If the transmitter is
forced to send a continuous low condition by issuing a SEND BREAK command, the
transmitter ignores the state of CTS.
If the transmitter is programmed to automatically negate RTS when a message transmission
completes, RTS must be asserted manually before a message is sent. In applications in
which the transmitter is disabled after transmission is complete and RTS is appropriately
programmed, RTS is negated one bit time after the character in the shift register is
completely transmitted. The transmitter must be manually reenabled by reasserting RTS
before the next message is to be sent.
Figure 14-21 shows the functional timing information for the transmitter.
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14-21
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Operation
C1 in transmission
C11
TxD
C2
C3
C4
Break
C6
Transmitter
Enabled
Freescale Semiconductor, Inc...
USRn[TxRDY]
internal
module
select
W2
W
W
C11
C2
C3 Start
break
W
W
W
C4 Stop
break
W
W
C5
not
transmitted
C6
CTS3
RTS4
Manually asserted
by BIT-SET command
Manually
asserted
1 Cn = transmit characters
2 W = write
3 UMR2n[TxCTS] = 1
4 UMR2n[TxRTS] = 1
Figure 14-21. Transmitter Timing Diagram
14.5.2.2 Receiver
The receiver is enabled through its UCRn, as described in Section 14.3.5, “UART
Command Registers (UCRn).” Figure 14-22 shows receiver functional timing.
14-22
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TxD
C1
C2
C3
C4
C5
C6
Operation
C7
C8
C6, C7, and C8 will be lost
Receiver
Enabled
USRn[RxRDY]
USRn[FFULL]
Freescale Semiconductor, Inc...
internal
module
select
Status
Data
C5 will
be lost
(C1)
Status Status Status
Data Data Data
Reset by
command
Overrun
USRn[OE]
RTS4
(C2) (C3) (C4)
Manually asserted first time,
automatically negated if overrun occurs
UOP0[RTS] = 1
Automatically asserted
when ready to receive
Figure 14-22. Receiver Timing
When the receiver detects a high-to-low (mark-to-space) transition of the start bit on RxD,
the state of RxD is sampled each 16× clock for eight clocks, starting one-half clock after
the transition (asynchronous operation) or at the next rising edge of the bit time clock
(synchronous operation). If RxD is sampled high, the start bit is invalid and the search for
the valid start bit begins again.
If RxD is still low, a valid start bit is assumed and the receiver continues sampling the input
at one-bit time intervals, at the theoretical center of the bit, until the proper number of data
bits and parity, if any, is assembled and one stop bit is detected. Data on the RxD input is
sampled on the rising edge of the programmed clock source. The lsb is received first. The
data is then transferred to a receiver holding register and USRn[RxRDY] is set. If the
character is less than eight bits, the most significant unused bits in the receiver holding
register are cleared.
After the stop bit is detected, the receiver immediately looks for the next start bit. However,
if a non-zero character is received without a stop bit (framing error) and RxD remains low
for one-half of the bit period after the stop bit is sampled, the receiver operates as if a new
start bit were detected. Parity error, framing error, overrun error, and received break
conditions set the respective PE, FE, OE, RB error and break flags in the USRn at the
received character boundary and are valid only if USRn[RxRDY] is set.
If a break condition is detected (RxD is low for the entire character including the stop bit),
a character of all zeros is loaded into the receiver holding register (RHR) and
USRn[RB,RxRDY] are set. RxD must return to a high condition for at least one-half bit
time before a search for the next start bit begins.
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14-23
Operation
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The receiver detects the beginning of a break in the middle of a character if the break
persists through the next character time. If the break begins in the middle of a character, the
receiver places the damaged character in the Rx FIFO stack and sets the corresponding
USRn error bits and USRn[RxRDY]. Then, if the break lasts until the next character time,
the receiver places an all-zero character into the Rx FIFO and sets USRn[RB,RxRDY].
14.5.2.3 FIFO Stack
Freescale Semiconductor, Inc...
The FIFO stack is used in the UART’s receiver buffer logic. The stack consists of three
receiver holding registers. The receive buffer consists of the FIFO and a receiver shift
register connected to the RxD (see Figure 14-20). Data is assembled in the receiver shift
register and loaded into the top empty receiver holding register position of the FIFO. Thus,
data flowing from the receiver to the CPU is quadruple-buffered.
In addition to the data byte, three status bits, parity error (PE), framing error (FE), and
received break (RB), are appended to each data character in the FIFO; OE (overrun error)
is not appended. By programming the ERR bit in the channel’s mode register (UMR1n),
status is provided in character or block modes.
USRn[RxRDY] is set when at least one character is available to be read by the CPU. A read
of the receiver buffer produces an output of data from the top of the FIFO stack. After the
read cycle, the data at the top of the FIFO stack and its associated status bits are popped and
the receiver shift register can add new data at the bottom of the stack. The FIFO-full status
bit (FFULL) is set if all three stack positions are filled with data. Either the RxRDY or
FFULL bit can be selected to cause an interrupt.
The two error modes are selected by UMR1n[ERR] as follows:
•
•
In character mode (UMR1n[ERR] = 0, status is given in the USRn for the character
at the top of the FIFO.
In block mode, the USRn shows a logical OR of all characters reaching the top of
the FIFO stack since the last RESET ERROR STATUS command. Status is updated as
characters reach the top of the FIFO stack. Block mode offers a data-reception speed
advantage where the software overhead of error-checking each character cannot be
tolerated. However, errors are not detected until the check is performed at the end of
an entire message—the faulting character is not identified.
In either mode, reading the USRn does not affect the FIFO. The FIFO is popped only when
the receive buffer is read. The USRn should be read before reading the receive buffer. If all
three receiver holding registers are full, a new character is held in the receiver shift register
until space is available. However, if a second new character is received, the contents of the
the character in the receiver shift register is lost, the FIFOs are unaffected, and USRn[OE]
is set when the receiver detects the start bit of the new overrunning character.
To support flow control, the receiver can be programmed to automatically negate and assert
RTS, in which case the receiver automatically negates RTS when a valid start bit is detected
and the FIFO stack is full. The receiver asserts RTS when a FIFO position becomes
14-24
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Operation
available; therefore, overrun errors can be prevented by connecting RTS to the CTS input
of the transmitting device.
NOTE:
The receiver can still read characters in the FIFO stack if the
receiver is disabled. If the receiver is reset, the FIFO stack, RTS
control, all receiver status bits, and interrupt requests are reset.
No more characters are received until the receiver is reenabled.
Freescale Semiconductor, Inc...
14.5.3 Looping Modes
The UART can be configured to operate in various looping modes as shown in Figure 14-22
on page 14-23. These modes are useful for local and remote system diagnostic functions.
The modes are described in the following paragraphs and in Section 14.3, “Register
Descriptions.”
The UART’s transmitter and receiver should be disabled when switching between modes.
The selected mode is activated immediately upon mode selection, regardless of whether a
character is being received or transmitted.
14.5.3.1 Automatic Echo Mode
In automatic echo mode, shown in Figure 14-23, the UART automatically resends received
data bit by bit. The local CPU-to-receiver communication continues normally, but the
CPU-to-transmitter link is disabled. In this mode, received data is clocked on the receiver
clock and resent on TxD. The receiver must be enabled, but the transmitter need not be.
RxD Input
Rx
CPU
Disabled
Tx
Disabled
TxD Input
Figure 14-23. Automatic Echo
Because the transmitter is inactive, USRn[TxEMP,TxRDY] are inactive and data is sent as
it is received. Received parity is checked but is not recalculated for transmission. Character
framing is also checked, but stop bits are sent as they are received. A received break is
echoed as received until the next valid start bit is detected.
14.5.3.2 Local Loop-Back Mode
Figure 14-24 shows how TxD and RxD are internally connected in local loop-back mode.
This mode is for testing the operation of a local UART module channel by sending data to
the transmitter and checking data assembled by the receiver to ensure proper operations.
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Operation
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Rx
Disabled
RxD Input
Disabled
TxD Input
CPU
Tx
Figure 14-24. Local Loop-Back
Features of this local loop-back mode are as follows:
Freescale Semiconductor, Inc...
•
•
•
•
Transmitter and CPU-to-receiver communications continue normally in this mode.
RxD input data is ignored
TxD is held marking
The receiver is clocked by the transmitter clock. The transmitter must be enabled,
but the receiver need not be.
14.5.3.3 Remote Loop-Back Mode
In remote loop-back mode, shown in Figure 14-25, the channel automatically transmits
received data bit by bit on the TxD output. The local CPU-to-transmitter link is disabled.
This mode is useful in testing receiver and transmitter operation of a remote channel. For
this mode, the transmitter uses the receiver clock.
Because the receiver is not active, received data cannot be read by the CPU and error status
conditions are inactive. Received parity is not checked and is not recalculated for
transmission. Stop bits are sent as they are received. A received break is echoed as received
until the next valid start bit is detected.
Disabled
Rx
Disabled
RxD Input
Disabled
TxD Input
CPU
Disabled
Tx
Figure 14-25. Remote Loop-Back
14.5.4 Multidrop Mode
Setting UMR1n[PM] programs the UART to operate in a wake-up mode for multidrop or
multiprocessor applications. In this mode, a master can transmit an address character
followed by a block of data characters targeted for one of up to 256 slave stations.
Although slave stations have their channel receivers disabled, they continuously monitor
the master’s data stream. When the master sends an address character, the slave receiver
channel notifies its respective CPU by setting USRn[RxRDY] and generating an interrupt
(if programmed to do so). Each slave station CPU then compares the received address to its
station address and enables its receiver if it wishes to receive the subsequent data characters
or block of data from the master station. Slave stations not addressed continue monitoring
the data stream. Data fields in the data stream are separated by an address character. After
14-26
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Operation
a slave receives a block of data, its CPU disables the receiver and repeats the
process.Functional timing information for multidrop mode is shown in Figure 14-26.
Master Station
A/D
TxD
ADD1 1
A/D
A/D
C0
ADD2 1
Transmitter
Enabled
Freescale Semiconductor, Inc...
USRn[TxRDY]
internal
module
select
UMR1n[PM] = 11
UMR1n[PT] = 1
C0
ADD 1
UMR1n[PT] = 0
ADD 2
UMR1n[PT] = 2
Peripheral Station
RxD
A/D
A/D
0
ADD1 1
A/D
C0
A/D
A/D
ADD2 1
0
Receiver
Enabled
USRn[RxRDY]
internal
module
select
UMR1n[PM] = 11
UMR1n[PM] = 11
ADD 1
Status Data
(C0)
Status Data
(ADD 2)
Figure 14-26. Multidrop Mode Timing Diagram
A character sent from the master station consists of a start bit, a programmed number of
data bits, an address/data (A/D) bit flag, and a programmed number of stop bits. A/D = 1
indicates an address character; A/D = 0 indicates a data character. The polarity of A/D is
selected through UMR1n[PT]. UMR1n should be programmed before enabling the
transmitter and loading the corresponding data bits into the transmit buffer.
In multidrop mode, the receiver continuously monitors the received data stream, regardless
of whether it is enabled or disabled. If the receiver is disabled, it sets the RxRDY bit and
loads the character into the receiver holding register FIFO stack provided the received A/D
bit is a one (address tag). The character is discarded if the received A/D bit is zero (data
tag). If the receiver is enabled, all received characters are transferred to the CPU through
the receiver holding register stack during read operations.
In either case, the data bits are loaded into the data portion of the stack while the A/D bit is
loaded into the status portion of the stack normally used for a parity error (USRn[PE]).
Framing error, overrun error, and break detection operate normally. The A/D bit takes the
place of the parity bit; therefore, parity is neither calculated nor checked. Messages in this
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Operation
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mode may still contain error detection and correction information. One way to provide error
detection, if 8-bit characters are not required, is to use software to calculate parity and
append it to the 5-, 6-, or 7-bit character.
14.5.5 Bus Operation
This section describes bus operation during read, write, and interrupt acknowledge cycles
to the UART module.
14.5.5.1 Read Cycles
Freescale Semiconductor, Inc...
The UART module responds to reads with byte data. Reserved registers return zeros.
14.5.5.2 Write Cycles
The UART module accepts write data as bytes. Write cycles to read-only or reserved
registers complete normally without exception processing, but data is ignored.
NOTE:
The UART module is accessed by the CPU with zero wait
states, as BCLKO is used for the UART module.
14.5.5.3 Interrupt Acknowledge Cycles
The UART module supplies the interrupt vector in response to a UART IACK cycle. If
UIVRn is not initialized to provide a vector number, a spurious exception is taken if an
interrupt is generated. This works in conjunction with the interrupt controller, which allows
a programmable priority level.
14.5.6 Programming
The software flowchart, Figure 14-27, consists of the following:
•
•
14-28
UART module initialization—These routines consist of SINIT and CHCHK (sheets
1 and 2). Before SINIT is called at system initialization, the calling routine allocates
2 words on the system stack. On return to the calling routine, SINIT passes UART
status data on the stack. If SINIT finds no errors, the transmitter and receiver are
enabled. SINIT calls CHCHK to perform the checks. When called, SINIT places the
UART in local loop-back mode and checks for the following errors:
— Transmitter never ready
— Receiver never ready
— Parity error
— Incorrect character received
I/O driver routine—This routine (sheets 4 and 5) consists of INCH, the terminal
input character routine which gets a character from the receiver, and OUTCH, which
sends a character to the transmitter.
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•
Operation
Interrupt handling—Consists of SIRQ (sheet 4), which is executed after the UART
module generates an interrupt caused by a change-in-break (beginning of a break).
SIRQ then clears the interrupt source, waits for the next change-in-break interrupt
(end of break), clears the interrupt source again, then returns from exception
processing to the system monitor.
14.5.6.1 UART Module Initialization Sequence
NOTE:
UART module registers can be accessed by word or byte
operations, but only data byte D[7:0] is valid.
Freescale Semiconductor, Inc...
Table 14-14 shows the UART module initialization sequence.
Table 14-14. UART Module Initialization Sequence
Register
Setting
UCRn
Reset the receiver and transmitter.
Reset the mode pointer (MISC[2–0] = 0b001).
UIVRn
Program the vector number for a UART module interrupt.
UIMRn
Enable the preferred interrupt sources.
UACRn
Initialize the input enable control (IEC bit).
UCSRn
Select the receiver and transmitter clock. Use timer as source if required.
UMR1n
If preferred, program operation of receiver ready-to-send (RxRTS bit).
Select receiver-ready or FIFO-full notification (RxRDY/FFULL bit).
Select character or block error mode (ERR bit).
Select parity mode and type (PM and PT bits).
Select number of bits per character (B/Cx bits).
UMR2n
Select the mode of operation (CMx bits).
If preferred, program operation of transmitter ready-to-send (TxRTS).
If preferred, program operation of clear-to-send (TxCTS bit).
Select stop-bit length (SBx bits).
UCR
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Operation
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ENABLE
ENABLA
SERIAL MODULE
SINIT
ANY
ERRORS
?
INITIATE:
Y
N
CHANNEL
INTERRUPTS
ENABLE RECEIVER
Freescale Semiconductor, Inc...
CHK1
CALL CHCHK
SAVE CHANNEL
STATUS
ASSERT
REQUEST TO SEND
SINITR
RETURN
Figure 14-27. UART Mode Programming Flowchart (Sheet 1 of 5)
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Operation
CHCHK
CHCHK
PLACE CHANNEL IN
LOCAL LOOPBACK
MODE
Freescale Semiconductor, Inc...
ENABLE
TRANSMITTER CLEAR
STATUS WORD
TxCHK
N
IS
TRANSMITTER
READY
?
N
Y
WAITED
TOO LONG
?
Y
SET TRANSMITTERNEVER-READY FLAG
Y
SET RECEIVERNEVER-READY FLAG
N
Y
SNDCHR
SEND CHARACTER
TO TRANSMITTER
RxCHK
N
HAS
CHARACTER BEEN
RECEIVED
?
N
WAITED
TOO LONG
?
Y
A
B
Figure 14-27. UART Mode Programming Flowchart (Sheet 2 of 5)
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Operation
B
A
FRCHK
RSTCHN
HAVE
FRAMING ERROR
?
N
Y
RESTORE
TO ORIGINAL MODE
SET FRAMING
ERROR FLAG
PRCHK
Freescale Semiconductor, Inc...
DISABLE
TRANSMITTER
RETURN
HAVE
PARITY ERROR
?
N
Y
SET PARITY
ERROR FLAG
A
CHRCHK
GET CHARACTER
FROM RECEIVER
SAME AS
TRANSMITTED
CHARACTER
?
Y
N
SET INCORRECT
CHARACTER FLAG
B
Figure 14-27. UART Mode Programming Flowchart (Sheet 3 of 5)
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Operation
INCH
SIRQ
ABRKI
WAS
IRQ CAUSED
BY BEGINNING
OF A BREAK
?
Y
N
DOES
CHANNEL A
RECEIVER HAVE A
CHARACTER
?
N
Y
PLACE CHARACTER
IN D0
CLEAR CHANGE-INBREAK STATUS BIT
Freescale Semiconductor, Inc...
ABRKI1
HAS
END-OF-BREAK
IRQ ARRIVED
YET
?
RETURN
N
Y
CLEAR CHANGE-INBREAK STATUS BIT
REMOVE BREAK
CHARACTER FROM
RECEIVER FIFO
REPLACE RETURN
ADDRESS ON SYSTEM
STACK AND MONITOR
WARM START ADDRESS
SIRQR
RTE
Figure 14-27. UART Mode Programming Flowchart (Sheet 4 of 5)
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Operation
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OUTCH
IS
TRANSMITTER
READY
?
N
Y
Freescale Semiconductor, Inc...
SEND CHARACTER
TO TRANSMITTER
RETURN
Figure 14-27. UART Mode Programming Flowchart (Sheet 5 of 5)
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Chapter 15
Parallel Port (General-Purpose I/O)
This chapter describes the operation and programming model of the parallel port pin
assignment, direction-control, and data registers. It includes a code example for setting up
the parallel port.
15.1 Parallel Port Operation
The MCF5307 parallel port module has 16 signals, which are programmed as follows:
•
•
•
The pin assignment register (PAR) selects the function of the 16 multiplexed pins.
Port A data direction register (PADDR) determines whether pins configured as
parallel port signals are inputs or outputs.
The Port A data register (PADAT) shows the status of the parallel port signals.
The operations of the PAR, PADDR, and PADAT are described in the following sections.
15.1.1 Pin Assignment Register (PAR)
The pin assignment register (PAR), which is part of the system integration module (SIM),
defines how each PAR bit determines each pin function, as shown in Figure 15-1.
15
14
13
12
11
10
9
8
7
Field PAR15 PAR14 PAR13 PAR12 PAR11 PAR10 PAR9 PAR8 PAR7
6
5
4
3
2
1
0
PAR6
PAR5 PAR4 PAR3
PAR2 PAR1 PAR0
PP6
PP5
PAR[n] = 0 PP15
PP14
PP13
PP12
PP11
PP10
PP9
PP8
PP7
PP4
PP3
PP2
PP1
PP0
PAR[n] = 1
A30
A29
A28
A27
A26
A25
A24
TIP DREQ0 DREQ1 TM2
TM1
TM0
TT1
TT0
A31
Reset Determined by driving D4/ADDR_CONFIG with a 1 or 0 when RSTI negates. The system is configured as
PP[15:0] if D4 is low; otherwise alternate pin functions selected by PAR[n] = 1 are used.
R/W
Address
R/W
Address MBAR + 0x004
Figure 15-1. Parallel Port Pin Assignment Register (PAR)
If PP[9:8]/A[25:24] are unavailable because A[25:0] are needed for external addressing,
PP[15:10]/A[31:26] can be configured as general-purpose I/O. Table 15-1 summarizes
MCF5307 parallel port pins, described in detail in Chapter 17, “Signal Descriptions.”
Chapter 15. Parallel Port (General-Purpose I/O)
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15-1
Parallel Port Operation
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Table 15-1. Parallel Port Pin Descriptions
Pin
Description
PP[15:8]/
A[31:24]
MSB of the address bus/parallel port. Programmed through PAR[15–8]. If a PAR bit is 0, the associated
pin functions as a parallel port signal. If a bit is 1, the pin functions as an address bus signal. If all pins
are address signals, as much as 4 Gbytes of memory space are available.
TIP/PP7
Transfer-in-progress output/parallel port bit 7. Programmed through PAR[7]. Assertion indicates a bus
transfer is in progress; negation indicates an idle bus cycle if the bus is still granted to the processor.
Note that TIP is held asserted on back-to-back bus cycles.
Freescale Semiconductor, Inc...
DREQ[1:0]/ DMA request inputs/two bits of the parallel port. Programmed through PAR[6–5]. These inputs are
PP[6:5]
asserted by a peripheral device to request a DMA transfer.
TM[2:0]/
PP[4:2]]
Transfer type outputs/parallel port bits 4–2. Programmed through PAR[4–2]. For DMA transfers, these
signals provide acknowledge information. For emulation transfers, TM[2:0] indicate user or data transfer
types. For CPU space transfers, TM[2:0] are low. For interrupt acknowledge transfers, TM[2:0] carry the
interrupt level being acknowledged.
TT[1:0]/
PP[1:0]
Transfer type outputs/parallel port bits 1–0. Programmed through PAR[1–0].
When the MCF5307 is bus master, it outputs these signals. They indicate the current bus access type.
15.1.2 Port A Data Direction Register (PADDR)
The PADDR determines the signal direction of each parallel port pin programmed as a
general-purpose I/O port in the PAR.
15
0
Field
PADDR
Reset
0000_0000_0000_0000
R/W
R/W
Address
Address MBAR + 0x244
Figure 15-2. Port A Data Direction Register (PADDR)
Table 15-2 describes PADDR fields.
Table 15-2. PADDR Field Description
Bits
Name
15–0
PADDR
Description
Data direction bits. Each data direction bit selects the direction of the signal as follows:
0 Signal is defined as an input.
1 Signal is defined as an output.
15.1.3 Port A Data Register (PADAT)
The PADAT value for inputs corresponds to the logic level at the pin; for outputs, the value
corresponds to the logic level driven onto the pin. Note the following:
•
•
15-2
PADAT has no effect on pins not configured for general-purpose I/O.
PADAT settings do not affect inputs. PADAT bit values determine the corresponding
logic levels of pins configured as outputs.
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•
Parallel Port Operation
PADAT can be written to anytime. A read from PADAT returns values of
corresponding pins configured as general-purpose I/O in the PAR and designated as
inputs by the PADDR.
15
0
Field
PADAT
Reset
0000_0000_0000_0000
R/W
R/W
Address
Address MBAR+0x248
Freescale Semiconductor, Inc...
Figure 15-3. Port A Data Register (PADAT)
Table 15-3 shows relationships between PADAT bits and parallel port pins when PADAT is
accessed. The effect differs when the parallel port pin is an input or output.
The following results occur when a parallel port pin is configured as an input:
•
•
When the PADAT is read, the value returned is the logic value on the pin.
When the PADAT is written, the register contents are updated without affecting the
logic value on the pin.
The following results occur when a parallel port pin is configured as an output:
•
•
When the PADAT is read, the register contents are returned and the pin is the logic
value of the register.
When the PADAT is written, the register contents are updated and the pin is the logic
value of the register.
These relationships are also described in Table 15-3.
Table 15-3. Relationship between PADAT Register and Parallel Port Pin (PP)
PP Status PADAT R/W
Effect on PADAT
Effect on PP
Read
Register bit value is the pin’s logic value
No effect. Source of logic value
Write
Register contents updated
No effect on the logic value at the pin
Read
Register contents are returned
Pin is the logic value of the register bit
Write
Register contents updated
Pin is the logic value of the register bit
Input
Output
NOTE:
Although external devices cannot access the MCF5307’s
on-chip memories or MBAR, they can access any parallel port
module registers in the SIM.
15.1.4 Code Example
The following code example shows how to set up the parallel port. Here, PP[7:0] are
general-purpose I/O, PP[3:0] are inputs, and PP[7:4] are outputs.
Chapter 15. Parallel Port (General-Purpose I/O)
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15-3
Parallel Port Operation
Freescale Semiconductor, Inc.
EQU
EQU
EQU
EQU
0x00010000
MBARx+0x004
MBARx+0x244
MBARx+0x248
move.l
movec
move.w
move.w
move.w
move.w
move.b
move.b
#MBARx,D0
D0, MBAR
#0x00FF,D0
D0,PAR
#0x00F0,D0
D0,PADDR
#0xA0,D0
D0,PADAT
;because MBAR is an internal register, MBARx is used as
;label for the memory map address
;set up the PAR. PP[7:0] set up as I/O
;set PP[7:4] as outputs; PP[3:0] as inputs
;0xA0 written into PADAT; PP[7:4] being outputs,
;PP[7:4] becomes 1010; i.e. PP7, PP5 = 1 and
;PP6, PP4 = 0
Freescale Semiconductor, Inc...
MBARx
PAR
PADDR
PADAT
15-4
MCF5307 User’s Manual
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Freescale Semiconductor, Inc...
Part IV
Hardware Interface
Intended Audience
Part IV is intended for hardware designers who need to know the functions and electrical
characteristics of the MCF5407 interface. It includes a pinout, and both electrical and
functional descriptions of the MCF5307 signals. It also describes how these signals interact
to support the variety of bus operations shown in timing diagrams.
Contents
Part IV contains the following chapters:
•
•
•
•
•
Chapter 16, “Mechanical Data,” provides a functional pin listing and package
diagram for the MCF5307.
Chapter 17, “Signal Descriptions,” provides an alphabetical listing of MCF5307
signals. This chapter describes the MCF5307 signals. In particular, it shows which
are inputs or outputs, how they are multiplexed, which signals require pull-up
resistors, and the state of each signal at reset.
Chapter 18, “Bus Operation,” describes data transfers, error conditions, bus
arbitration, and reset operations. It describes transfers initiated by the MCF5307 and
by an external bus master, and includes detailed timing diagrams showing the
interaction of signals in supported bus operations. Note that Chapter 11,
“Synchronous/Asynchronous DRAM Controller Module,” describes DRAM cycles.
Chapter 19, “IEEE 1149.1 Test Access Port (JTAG),” describes configuration and
operation of the MCF5307 JTAG test implementation. It describes the use of JTAG
instructions and provides information on how to disable JTAG functionality.
Chapter 20, “Electrical Specifications,” describes AC and DC electrical
specifications and thermal characteristics for the MCF5307. Because additional
speeds may have become available since the publication of this book, consult
Motorola’s ColdFire web page, http://www.motorola.com/coldfire, to confirm that
this is the latest information.
Part IV. Hardware Interface
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IV-i
Freescale Semiconductor, Inc.
Suggested Reading
The following literature may be helpful with respect to the topics in Part IV:
•
•
IEEE Standard Test Access Port and Boundary-Scan Architecture
IEEE Supplement to Standard Test Access Port and Boundary-Scan Architecture
(1149.1)
Acronyms and Abbreviations
Table IV-i describes acronyms and abbreviations used in Part IV.
Freescale Semiconductor, Inc...
Table IV-i. Acronyms and Abbreviated Terms
Term
Meaning
BDM
Background debug mode
BIST
Built-in self test
BSDL
Boundary-scan description language
DMA
Direct memory access
DSP
Digital signal processing
EDO
Extended data output (DRAM)
GPIO
I2C
Inter-integrated circuit
IEEE
Institute for Electrical and Electronics Engineers
IPL
Interrupt priority level
JEDEC
Joint Electron Device Engineering Council
JTAG
Joint Test Action Group
LSB
Least-significant byte
lsb
Least-significant bit
MAC
Multiple accumulate unit
MBAR
Memory base address register
MSB
Most-significant byte
msb
Most-significant bit
Mux
Multiplex
PCLK
Processor clock
PLL
Phase-locked loop
POR
Power-on reset
PQFP
Plastic quad flat pack
IV-ii
MCF5307 User’s Manual
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Table IV-i. Acronyms and Abbreviated Terms (Continued)
Term
Meaning
Reduced instruction set computing
Rx
Receive
SIM
System integration module
TAP
Test access port
TTL
Transistor-to-transistor logic
Tx
Transmit
Freescale Semiconductor, Inc...
RISC
Part IV. Hardware Interface
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IV-iii
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Freescale Semiconductor, Inc.
IV-iv
MCF5307 User’s Manual
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Chapter 16
Mechanical Data
Freescale Semiconductor, Inc...
This chapter provides a function pin listing and package diagram for the MCF5307. See the
website [http://www.motorola.com/coldfire] for any updated information.
16.1 Package
The MCF5307 is assembled in a 208-pin, thermally enhanced plastic QFP package.
16.2 Pinout
The MCF5307 pinout is detailed in the following tables, including the primary and
secondary functions of multiplexed signals. Additional columns indicate the output drive
capability of each pin, whether it is internally synchronized, and if the signal can change
on a negative clock transition.
These tables show MCF5307 pin numbers, including signal multiplexing. Additional
columns indicate the direction, description, and output drive capability of each pin.
Table 16-1. Pins 1–52 (Left, Top-to-Bottom)
Pin
Alternate
Function
I/O
Description
Drive
(mA)
No
Name
1
VCC
—
—
Power input
—
2
A0
—
I/O
Address bus bit
8
3
A1
—
I/O
Address bus bit
8
4
GND
—
—
Ground pin
—
5
A2
—
I/O
Address bus bit
8
6
A3
—
I/O
Address bus bit
8
7
VCC
—
—
Power input
—
8
A4
—
I/O
Address bus bit
8
9
A5
—
I/O
Address bus bit
8
10
GND
—
—
Ground pin
—
11
A6
—
I/O
Address bus bit
8
12
A7
—
I/O
Address bus bit
8
Chapter 16. Mechanical Data
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16-1
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Pinout
Table 16-1. Pins 1–52 (Left, Top-to-Bottom) (Continued)
Freescale Semiconductor, Inc...
Pin
16-2
Alternate
Function
I/O
Description
Drive
(mA)
No
Name
13
VCC
—
—
Power input
—
14
A8
—
I/O
Address bus bit
8
15
A9
—
I/O
Address bus bit
8
16
A10
—
I/O
Address bus bit
8
—
17
GND
—
—
Ground pin
18
A11
—
I/O
Address bus bit
8
19
A12
—
I/O
Address bus bit
8
20
A13
—
I/O
Address bus bit
8
21
VCC
—
—
Power input
—
22
A14
—
I/O
Address bus bit
8
23
A15
—
I/O
Address bus bit
8
24
A16
—
I/O
Address bus bit
8
25
GND
—
—
Ground pin
—
26
A17
—
I/O
Address bus bit
8
27
A18
—
I/O
Address bus bit
8
28
A19
—
I/O
Address bus bit
8
29
VCC
—
—
Power input
—
30
A20
—
I/O
Address bus bit
8
31
A21
—
I/O
Address bus bit
8
32
A22
—
I/O
Address bus bit
8
33
GND
—
—
Ground pin
—
34
A23
—
I/O
Address bus bit
8
35
PP8
A24
I/O
Parallel port bit/Address bus bit
8
36
PP9
A25
I/O
Parallel port bit/Address bus bit
8
37
VCC
—
—
Power input
—
38
PP10
A26
I/O
Parallel port bit/Address bus bit
8
39
PP11
A27
I/O
Parallel port bit/Address bus bit
8
40
PP12
A28
I/O
Parallel port bit/Address bus bit
8
41
GND
—
—
Ground pin
—
42
PP13
A29
I/O
Parallel port bit/Address bus bit
8
43
PP14
A30
I/O
Parallel port bit/Address bus bit
8
44
PP15
A31
I/O
Parallel port bit/Address bus bit
8
45
VCC
—
—
Power input
—
46
SIZ0
—
I/O
Size attribute
8
47
SIZ1
—
I/O
Size attribute
8
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Pinout
Table 16-1. Pins 1–52 (Left, Top-to-Bottom) (Continued)
Pin
No
Name
Alternate
Function
I/O
Description
Drive
(mA)
48
GND
—
—
Ground pin
—
49
OE
—
O
Output enable for chip selects
8
50
CS0
—
O
Chip select
8
51
CS1
—
O
Chip select
8
52
VCC
—
—
Power input
—
Freescale Semiconductor, Inc...
Table 16-2. Pins 53–104 (Bottom, Left-to-Right)
Pin
Alternate
Function
I/O
GND
—
—
Ground pin
—
CS2
—
O
Chip select
8
55
CS3
—
O
Chip select
8
56
CS4
—
O
Chip select
8
57
VCC
—
—
Power input
—
58
CS5
—
O
Chip select
8
59
CS6
—
O
Chip select
8
60
CS7
—
O
Chip select
8
61
GND
—
—
Ground pin
—
62
AS
—
I/O
Address strobe
8
No
Name
53
54
Description
Drive
(mA)
63
R/W
—
I/O
Read/Write
8
64
TA
—
I/O
Transfer acknowledge
8
65
VCC
—
—
Power input
—
66
TS
—
I/O
Transfer start
8
67
RSTI
—
I
Reset
—
68
IRQ7
—
I
69
GND
—
—
70
IRQ5
IRQ4
71
IRQ3
IRQ6
72
IRQ1
73
74
Interrupt request
—
Ground pin
—
I
Interrupt request
—
I
Interrupt request
—
IRQ2
I
Interrupt request
—
VCC
—
—
Power input
—
BR
—
O
Bus request
8
75
BD
—
O
Bus driven
8
76
BG
—
I
Bus grant
—
77
GND
—
—
Ground pin
—
Chapter 16. Mechanical Data
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16-3
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Pinout
Table 16-2. Pins 53–104 (Bottom, Left-to-Right) (Continued)
Freescale Semiconductor, Inc...
Pin
1
Alternate
Function
I/O
TOUT1
—
O
Timer output
8
TOUT0
—
O
Timer output
8
Description
Drive
(mA)
No
Name
78
79
80
TIN0
—
I
Timer input
—
81
VCC
—
—
Power input
—
82
TIN1
—
I
Timer input
—
83
RAS0
—
O
DRAM row address strobe
16
84
RAS1
—
O
DRAM row address strobe
16
85
GND
—
—
Ground pin
—
86
CAS0
—
O
DRAM column address strobe
16
87
CAS1
—
O
DRAM column address strobe
16
88
CAS2
—
O
DRAM column address strobe
16
89
VCC
—
—
Power input
—
90
CAS3
—
O
DRAM column address strobe
16
91
DRAMW
—
O
DRAM write
16
92
SRAS
—
O
SDRAM row address strobe
16
93
GND
—
—
Ground pin
—
94
SCAS
—
O
SDRAM column address strobe
16
95
SCKE
—
O
SDRAM clock enable
16
96
BE0
BWE0
O
Byte enable/byte write enable
8
97
VCC
—
—
Power input
—
98
BE1
BWE1
O
Byte enable/byte write enable
8
99
BE2
BWE2
O
Byte enable/byte write enable
8
100
BE3
BWE3
O
Byte enable/byte write enable
8
101
GND
—
—
Ground pin
—
102
SCL
—
I/OD 1 Serial clock line
103
SDA
—
I/OD 1 Serial data line
104
GND
—
—
Ground pin
8
8
—
OD: Open-drain output
Table 16-3. Pins 105–156 (Right, Bottom-to-Top)
Pin
No
16-4
Name
Alternate
Function
I/O
Description
Drive
(mA)
105
VCC
—
—
Power input
—
106
D31
—
I/O
Data bus
8
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Pinout
Table 16-3. Pins 105–156 (Right, Bottom-to-Top) (Continued)
Pin
Freescale Semiconductor, Inc...
No
Name
Alternate
Function
I/O
Description
Drive
(mA)
107
D30
—
I/O
Data bus
8
108
D29
—
I/O
Data bus
8
109
GND
—
—
Ground pin
—
110
D28
—
I/O
Data bus
8
111
D27
—
I/O
Data bus
8
112
D26
—
I/O
Data bus
8
113
VCC
—
—
Power input
—
114
D25
—
I/O
Data bus
8
115
D24
—
I/O
Data bus
8
116
D23
—
I/O
Data bus
8
117
GND
—
—
Ground pin
—
118
D22
—
I/O
Data bus
8
119
D21
—
I/O
Data bus
8
120
D20
—
I/O
Data bus
8
—
121
VCC
—
—
Power input
122
D19
—
I/O
Data bus
8
123
D18
—
I/O
Data bus
8
124
D17
—
I/O
Data bus
8
125
GND
—
—
Ground pin
—
126
D16
—
I/O
Data bus
8
127
D15
—
I/O
Data bus
8
128
D14
—
I/O
Data bus
8
129
VCC
—
—
Power input
—
130
D13
—
I/O
Data bus
8
131
D12
—
I/O
Data bus
8
132
D11
—
I/O
Data bus
8
133
GND
—
—
Ground pin
—
134
D10
—
I/O
Data bus
8
135
D9
—
I/O
Data bus
8
136
D8
—
I/O
Data bus
8
137
VCC
—
—
Power input
—
138
D7
CS_CONF2
I/O
Data bus/Chip select configuration
8
139
D6
CS_CONF1
I/O
Data bus/Chip select configuration
8
140
D5
CS_CONF0
I/O
Data bus/Chip select configuration
8
141
GND
—
—
Ground pin
—
Chapter 16. Mechanical Data
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16-5
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Pinout
Table 16-3. Pins 105–156 (Right, Bottom-to-Top) (Continued)
Pin
Freescale Semiconductor, Inc...
No
Name
Alternate
Function
I/O
Description
Drive
(mA)
142
D4
ADDR_CONF
I/O
Data bus/Address configuration
8
143
D3
FREQ1
I/O
Data bus/CLKIN Frequency
8
144
D2
FREQ0
I/O
Data bus/CLKIN Frequency
8
145
VCC
—
—
Power input
—
146
D1
DIVIDE1
I/O
Data bus/Divide control PCLK:BCLKO
8
147
D0
DIVIDE0
I/O
Data bus/Divide control PCLK:BCLKO
8
148
GND
—
—
Ground pin
—
149
DSCLK
TRST
I
Debug serial clock/JTAG Reset
—
150
TCK
TCK
I
JTAG clock
—
151
DSO
TDO
O
Debug serial out/JTAG data out
8
152
VCC
—
—
Power input
—
153
DSI
TDI
I
Debug serial input/JTAG data in
—
154
BKPT
TMS
I
Debug breakpoint/JTAG mode select
—
155
HIZ
—
I
High impedance override
—
156
GND
—
—
Ground pin
—
Table 16-4. Pins 157–208 (Top, Right-to-Left)
Pin
No
16-6
Name
Alternate
Function
I/O
Description
Drive
(mA)
157
VCC
—
—
Power input
—
158
CTS1
—
I
UART1 clear-to-send
—
159
RTS1
—
O
UART1 request-to-send
8
160
RXD1
—
I
UART1 receive data
—
161
TXD1
—
O
UART1 transmit data
8
162
GND
—
—
Ground pin
—
163
CTS0
—
I
UART0 clear-to-send
—
164
RTS0
—
O
UART0 request-to-send
8
165
RXD0
—
I
UART0 receive data
—
166
TXD0
—
O
UART0 transmit data
8
167
VCC
—
—
Power input
—
168
EDGESEL
—
I
SDRAM bus clock edge select
—
169
GND
—
—
Ground pin
—
170
BCLKO
—
O
Bus clock output
16
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Pinout
Table 16-4. Pins 157–208 (Top, Right-to-Left) (Continued)
Pin
Freescale Semiconductor, Inc...
No
Name
Alternate
Function
I/O
Description
Drive
(mA)
171
VCC
—
—
Power input
—
172
RSTO
—
O
Processor reset output
8
173
GND
—
—
Ground pin
—
174
CLKIN
—
I
Clock input
—
175
VCC
—
—
Power input
—
176
MTMOD0
—
I
JTAG/BDM select (Tie high or low)
—
177
MTMOD1
—
I
Tie high or low
—
178
PGND
—
—
PLL ground pin
179
NC
—
O
180
PVCC
—
—
Filter supply for PLL
—
181
MTMOD2
—
I
Tie high or low
—
182
MTMOD3
—
I
Tie high or low
—
183
GND
—
—
Ground pin
—
184
PSTCLK
—
O
Processor status clock
8
185
VCC
—
—
Power input
—
186
DDATA0
—
O
Debug data
8
187
DDATA1
—
O
Debug data
8
188
GND
—
—
Ground pin
—
189
DDATA2
—
O
Debug data
8
190
DDATA3
—
O
Debug data
8
191
VCC
—
—
Power input
—
192
PST0
—
O
Processor status
8
193
PST1
—
O
Processor status
8
194
GND
—
—
Ground pin
—
—
—
195
PST2
—
O
Processor status
8
196
PST3
—
O
Processor status
8
197
VCC
—
—
Power input
—
198
PP7
TIP
I/O
Parallel port bit/transfer in progress
8
199
PP6
DREQ0
I/O
Parallel port bit/DMA request
8
200
PP5
DREQ1
I/O
Parallel port bit/DMA request
8
201
GND
—
—
Ground pin
—
202
PP4
TM2
I/O
Parallel port bit/Transfer modifier
8
203
PP3
TM1
I/O
Parallel port bit/Transfer modifier
8
204
PP2
TM0
I/O
Parallel port bit/Transfer modifier
8
205
VCC
—
—
Power input
—
Chapter 16. Mechanical Data
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16-7
Mechanical Diagram
Freescale Semiconductor, Inc.
Table 16-4. Pins 157–208 (Top, Right-to-Left) (Continued)
Pin
Alternate
Function
I/O
PP1
TT1
I/O
Parallel port bit/Transfer type
8
PP0
TT0
I/O
Parallel port bit/Transfer type
8
GND
—
—
Ground pin
—
No
Name
206
207
208
Description
16.3 Mechanical Diagram
Freescale Semiconductor, Inc...
Figure 16-1 is a mechanical diagram of the 208-pin QFP MCF5307.
16-8
MCF5307 User’s Manual
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Drive
(mA)
Freescale Semiconductor, Inc.
GND
PP0
PP1
VCC
PP2
PP3
PP4
GND
PP5
PP6
PP7
VCC
PST3
PST2
GND
PST1
PST0
EVCC
DDATA3
DDATA2
GND
DDATA1
DDATA0
VCC
PSTCLK
GND
MTMOD3
MTMOD2
PVCC
NC
PGND
MTMOD1
MTMOD0
VCC
CLKIN
GND
RSTO
VCC
BCLKO
GND
EDGESEL
VCC
TXD0
RXD0
RTS0
CTS0
GND
TXD1
RXD1
RTS1
CTS1
VCC
Case Drawing
160
165
170
175
180
185
190
205
156
GND
HIZ
BKPT
DSI
VCC
DSO
TCK
DSCLK
GND
D0
D1
VCC
D2
D3
D4
GND
D5
D6
D7
VCC
D8
D9
D10
GND
D11
D12
D13
VCC
D14
D15
D16
GND
D17
D18
D19
VCC
D20
D21
D22
GND
D23
D24
D25
VCC
D26
D27
D28
GND
D29
D30
D31
VCC
155
5
150
10
145
15
140
20
135
25
130
30
125
35
120
40
115
45
110
100
95
90
85
80
75
70
65
52
60
55
50
105
53
105
104
GND
CS2
CS3
CS4
VCC
CS5
CS6
CS7
GND
AS
R/W
TA
VCC
TS
RSTI
IRQ7
GND
IRQ5
IRQ3
IRQ1
VCC
BR
BD
BG
GND
TOUT1
TOUT0
TIN0
VCC
TIN1
RAS0
RAS1
GND
CAS0
CAS1
CAS2
VCC
CAS3
DRAMW
SRAS
GND
SCAS
SCKE
BE0
VCC
BE1
BE2
BE3
GND
SCL
SDA
GND
Freescale Semiconductor, Inc...
1
VCC
A0
A1
GND
A2
A3
VCC
A4
A5
GND
A6
A7
VCC
A8
A9
A10
GND
A11
A12
A13
VCC
A14
A15
A16
GND
A17
A18
A19
VCC
A20
A21
A22
GND
A23
PP8
PP9
VCC
PP10
PP11
PP12
GND
PP13
PP14
PP15
VCC
SIZ0
SIZ1
GND
OE
CS0
CS1
VCC
195
157
200
208
Figure 16-1. Mechanical Diagram
16.4 Case Drawing
Figure 16-2 and Figure 16-3 show the MCF5307 case drawings.
Chapter 16. Mechanical Data
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16-9
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Freescale Semiconductor, Inc...
Case Drawing
Figure 16-2. MCF5307 Case Drawing (General View)
16-10
MCF5307 User’s Manual
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Freescale Semiconductor, Inc...
View A: Three Places
Case Drawing
Section A-A: 160 Places Rotated 90° CW
View B
Figure 16-3. Case Drawing (Details)
The dimensions in Figure 16-2 and Figure 16-3 are referenced in Table 16-5.
Table 16-5. Dimensions
Dimension (Millimeters)
Reference
Minimum
Maximum
A
—
4.10
A1
0.25
0.50
A2
3.20
3.60
b
0.17
0.27
b1
0.17
0.23
c
0.09
0.20
c1
0.09
0.16
D
30.60 BSC
Chapter 16. Mechanical Data
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16-11
Freescale Semiconductor, Inc.
Case Drawing
Table 16-5. Dimensions (Continued)
Dimension (Millimeters)
Reference
Minimum
D1
28.00 BSC
e
0.50 BSC
E
30.60 BSC
E1
28.00 BSC
L
0.45
L1
Freescale Semiconductor, Inc...
R1
16-12
Maximum
0.75
1.30 REF
0.08
—
R2
0.08
0.25
S
0.20
—
ϑ
0*
8*
ϑ1
0*
—
ϑ2
5*
16*
MCF5307 User’s Manual
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Freescale Semiconductor, Inc...
Chapter 17
Signal Descriptions
This chapter describes MCF5307 signals. It includes an alphabetical listing of signals,
showing multiplexing, whether it is an input or output to the MCF5307, the state at reset,
and whether a pull-up resistor should be used. The following chapter, Chapter 18, “Bus
Operation,” describes how these signals interact.
NOTE:
The terms ‘assertion’ and ‘negation’ are used to avoid
confusion when dealing with a mixture of active-low and
active-high signals. The term ‘asserted’ indicates that a signal
is active, independent of the voltage level. The term ‘negated’
indicates that a signal is inactive.
Active-low signals, such as SRAS and TA, are indicated with
an overbar.
17.1 Overview
Figure 17-1 shows the block diagram of the MCF5307 with the signal interface.
Chapter 17. Signal Descriptions
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Overview
TMS/BKPT
Test
Controller
2
2
Bus
Interface
Debug Module
4
4-Kbyte SRAM
32
DIV
External
to Internal
Bus
8
2
8
4
Chip
Selects
4
PST[3:0]
DDATA[3:0]
MAC
8-Kbyte
Unified Cache
Parallel
Port1
Internal Bus Arbiter
Interrupt
Controller
2
1 Note: Parallel
2 I2C
port pins (PPn) are multiplexed with other bus functions as shown.
is a Philips proprietary interface
Figure 17-1. MCF5307 Block Diagram with Signal Interfaces
Table 17-1 lists the MCF5307 signals grouped by functionality.
17-2
MCF5307 User’s Manual
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I2C
Module 2
SDA
PLL
Dual
Timer
Module
SCL
UART1
Serial
I/O
2
UART0
Serial
I/O
TOUT[1:0]
DMA
Module
2
DRAM
Controller
System
Integration
Module
(SIM)
TIN[1:0]
2
4
TxD0
RxD0
RTS0
CTS0
TxD1
RxD1
RTS1
CTS1
BCLKO
CLKIN
PSTCLK
4
ColdFire V3 Core
A[23:0]
CS[7:0]
BE[3:0]/BWE[3:0]
OE
IRQ7
IRQ5
IRQ3
IRQ1
RAS[1:0]
CAS[3:0]
DRAMW
SRAS
SCAS
SCKE
EDGESEL
JTAG
Port
TDI/DSI
TRST/DSCLK
24
A[31:24]/PP[15:8]
TM[2:0]/PP[4:2]
MTMOD[3:0]
HIZ
TDO/DSO
TCK
DREQ[1:0]/
PP[6:5]
Freescale Semiconductor, Inc...
BR
BG
BD
RSTI
RSTO
AS
TA
TS
TT[1:0]]/PP[1:0]
SIZ[1:0]
R/W
TIP/PP7
D[31:0]
Freescale Semiconductor, Inc.
Overview
Table 17-1. MCF5307 Signal Index
Signal Name
Abbreviation
Function
I/O
Reset
Pull-Up Page
17-7
Freescale Semiconductor, Inc...
Section 17.2, “MCF5307 Bus Signals”
Address
A[31:0]
32-bit address bus. A[4:2] indicate
the interrupt level for external
interrupts.
I/O
Three
state
17-7
Data
D[31:0]
Data bus. D[7:0] are loaded at reset
for bus configuration.
I/O
Three
state
17-8
Read/Write
R/W
Identifies read and write transfers
I/O
Three
state
Size
SIZ[1:0]
Indicates the data transfer size
I/O
Three
state
17-8
Transfer start
TS
Indicates the start of a bus transfer
I/O
Three
state
17-9
Address strobe
AS
Indicates a bus cycle has been
initiated and address is stable
I/O
Three
state
Up
17-9
Transfer acknowledge
TA
Assertion terminates transfer
synchronously
I/O
Three
state
Up
17-9
Transfer in progress
TIP/PP7
Indicates a bus cycle is in progress;
multiplexed with PP7
O
Parallel
port
17-10
Transfer type
TT[1:0]
Indicates transfer type: normal, CPU
space, emulator mode, or DMA;
multiplexed with PP[1:0]
O
Parallel
port
17-10
Transfer modifier
TM[2:0]
Provides transfer modifier
information; Multiplexed with
PP[4:2].
O
Parallel
port
17-10
Up
17-12
Section 17.3, “Interrupt Control Signals”
Interrupt request
IRQ7, IRQ5,
IRQ3, IRQ1
Four external interrupts are set to
default levels 1,3,5,7; user-alterable.
I
—
Up
Bus request
BR
Indicates processor needs bus
O
High
Bus grant
BG
Arbiter asserts to grant mastership.
I
—
Bus driven
BD
Indicates processor is driving bus
O
High
17-12
Note 1
Processor reset input
17-12
17-13
17-13
Section 17.5, “Clock and Reset Signals”
RSTI
17-12
17-12
Section 17.4, “Bus Arbitration Signals”
Reset in
17-8
I
—
Up
17-13
Clock input
CLKIN
Input used to clock internal logic
I
—
17-13
Bus clock out
BCLKO
Bus clock reference output
O
—
17-13
Reset out
RSTO
Processor reset output
O
Low
17-13
Auto-acknowledge
configuration 2
AA_CONFIG
Controls auto acknowledge timing
for CS0 at reset
I
—
17-14
Port size configuration 2 PS_CONFIG[1:0] Controls port size for CS0 at reset
I
—
User cfg 17-14
Address configuration 2
I
—
User cfg 17-14
ADDR_CONFIG
Programs parallel I/O ports
Chapter 17. Signal Descriptions
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Overview
Table 17-1. MCF5307 Signal Index (Continued)
Signal Name
Abbreviation
Function
I/O
Reset
Frequency control PLL
FREQ[1:0]
Indicates CLKIN frequency range.
I
17-15
Divide control PCLK to
BCLKO
DIVIDE[1:0]
Indicates the BCLKO/PSTCLK ratio.
I
17-15
17-15
Section 17.6, “Chip-Select Module Signals”
Freescale Semiconductor, Inc...
Pull-Up Page
Chip selects[7:0]
CS[7:0]
Enables peripherals at programmed
addresses; CS0 provides boot ROM
selection.
O
High
17-16
Byte enable[3:0]/
Byte write enable[3:0]
BE[3:0]/
BWE[3:0]
BE[3:0] select bytes in memory.
O
High
17-16
Output enable
OE
Output enable for chip select read
cycles
O
High
17-16
17-16
Section 17.7, “DRAM Controller Signals”
Row address strobe
RAS[1:0]
DRAM row address strobe
O
High
17-16
Column address strobe
CAS[3:0]
DRAM column address strobe
O
High
17-16
DRAM write
DRAMW
Asserted for DRAM write; negated
for DRAM read
O
High
17-17
Synchronous column
address strobe
SCAS
SDRAM column address strobe
O
High
17-17
Synchronous row
address strobe
SRAS
SDRAM row address strobe
O
High
17-17
Synchronous clock
enable
SCKE
Clock enable for external SDRAM
O
Low
17-17
Synchronous edge
select
EDGESEL
Timing select for external SDRAM
I
—
17-17
Section 17.8, “DMA Controller Module Signals”
DMA request
DREQ[1:0]
External DMA transfer request;
multiplexed with PP[6:5]
User cfg 17-17
I
—
17-18
17-18
Section 17.9, “Serial Module Signals”
Receive data
RxD[1:0]
Receive serial data input for UART
I
—
17-18
Transmit data
TxD[1:0]
Transmit serial data output for UART
O
High
17-18
Request-to-send
RTS[1:0]
UART asserts when ready to
receive data query.
O
High
17-18
Clear-to-send
CTS[1:0]
Signals UART that data can be sent
to peripheral
I
—
17-18
17-18
Section 17.10, “Timer Module Signals”
Timer input
TIN[1:0]
Clock input to timer or trigger to
timer value capture logic
I
—
Timer outputs
TOUT[1:0]
Outputs waveform or pulse.
O
High
Section 17.11, “Parallel I/O Port (PP[15:0])”
17-4
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17-19
17-19
17-19
Freescale Semiconductor, Inc.
Overview
Table 17-1. MCF5307 Signal Index (Continued)
Signal Name
Parallel port
Abbreviation
PP[15:0]
Function
I/O
Reset
Pull-Up Page
Interfaces with I/O; multiplexed with
bus address and attribute signals.
I/O
Input
17-19
Section 17.12, “I2C Module Signals”
17-19
Serial clock line
SCL
Clock signal for I2C operation
I/O
Open
drain
Up
17-19
Serial data line
SDA
Serial data port for I2C operation
I/O
Open
drain
Up
17-19
17-20
Section 17.13, “Debug and Test Signals”
Freescale Semiconductor, Inc...
Motorola test mode
MTMOD0
Puts processor in functional or
emulator mode
I
—
User cfg 17-20
Motorola test mode
MTMOD[3:1]
Reserved
I
—
Down
17-20
High impedance
HIZ
Assertion three-states all outputs
I
—
Up
17-20
Processor clock out
PSTCLK
Output clock used for PSTDDATA
O
—
17-20
Processor status
PST[3:0]
Displays captured processor data .
O
Driven
17-20
Debug data
DDATA[3:0]
Displays captured processor data
and breakpoint status.
O
Driven
17-20
17-21
Section 17.14, “Debug Module/JTAG Signals”
Test clock
TCK
Clock signal for IEEE 1149.1 JTAG
I
—
Low
17-23
Test reset/
Development serial
clock
TRST/DSCLK
Asynchronous reset for JTAG;
debug module clock input
I
—
Up
17-21
Test mode select/
Breakpoint
TMS/BKPT
TMS (JTAG)/hardware breakpoint
(debug)
I
—
Up
17-22
Test data input/
Development serial
input
TDI/DSI
Multiplexed serial input for the JTAG
or background debug module
I
—
Up
17-22
Test data output/
Development serial
output
TDO/DSO
Multiplexed serial output for the
JTAG or background debug module
O
Driven
1
2
17-22
If there is no arbiter, BG should be tied low; otherwise, it should be negated.
These data pins are sampled at reset for configuration.
Table 17-2 lists signals in alphabetical order by abbreviated name.
Table 17-2. MCF507 Alphabetical Signal Index
Abbreviation
Signal Name
Function
I/O
Page
AA_CONFIG
Auto-acknowledge configuration
Clock/reset
I
17-14
ADDR_CONFIG
Address configuration
Clock/reset
I
17-14
AS
Address strobe
Bus
I/O
17-9
A[31:0]
Address
Bus
I/O
17-7
Chapter 17. Signal Descriptions
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Overview
Table 17-2. MCF507 Alphabetical Signal Index (Continued)
Abbreviation
Signal Name
I/O
Page
BCLKO
Bus clock out
Clock/reset
O
17-13
BD
Bus driven
Bus arbitration
O
17-13
BE[3:0]/BWE[3:0] Byte enable[3:0]/Byte write enable[3:0]
Freescale Semiconductor, Inc...
Function
Chip select
O
17-16
BG
Bus grant
Bus arbitration
I
17-12
BR
Bus request
Bus arbitration
O
17-12
CAS[3:0]
Column address strobe
DRAM
O
17-16
CLKIN
Clock input
Clock/reset
I
17-13
17-16
CS[7:0]
Chip selects[7:0]
UART
O
CTS[1:0]
Clear-to-send
Serial module
I
17-18
DDATA[3:0]
Debug data
Debug
O
17-20
Clock/Reset
I
17-15
DRAMW
DRAM write
DRAM
O
17-17
17-18
DREQ[1:0]
DMA request
DMA
I
D[31:0]
Data
Bus
I/O
17-8
EDGESEL
Sync edge select
DRAM
I
17-17
Clock/Reset
I
17-15
HIZ
High impedance
Debug
I
17-20
IRQ7, IRQ5,
IRQ3, IRQ1
Interrupt request
Interrupt control
I
17-12
MTMOD[3:0]
Motorola test mode
Debug
I
17-20
OE
Output enable
Chip select
O
17-16
PP[15:0]
Parallel port
Parallel port
I/O
17-19
PSTCLK
Processor clock out
Debug
O
17-20
PST[:0]
Processor status
Debug
O
17-20
Clock/reset
I
17-14
PS_CONFIG[1:0] Port size configuration
R/W
Read/Write
Bus
I/O
17-8
RAS[1:0]
Row address strobe
DRAM
O
17-16
RSTI
Reset In
Clock/reset
I
17-13
RSTO
Reset Out
Clock/reset
O
17-13
RTS[1:0]
Request-to-send
Serial module
O
17-18
RxD[1:0]
Receive data
Serial module
I
17-18
SCAS
Synchronous column address strobe
DRAM
O
17-17
SCKE
Synchronous clock enable
DRAM
O
17-17
SCL
Serial clock line
I2C
I/O
17-19
SDA
Serial data line
I2C
I/O
17-19
SIZ[1:0]
Size
Bus
I/O
17-8
17-6
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MCF5307 Bus Signals
Table 17-2. MCF507 Alphabetical Signal Index (Continued)
Freescale Semiconductor, Inc...
Abbreviation
Signal Name
Function
I/O
Page
SRAS
Synchronous row address strobe
DRAM
O
17-17
TA
Transfer acknowledge
Bus
I/O
17-9
TCK
Test clock
JTAG
I
17-23
TDI/DSI
Test data input/Development serial input
JTAG
I
17-22
TDO/DSO
Test data output/Development serial output
JTAG
O
17-22
TIN[1:0]
Timer input
Timer
I
17-19
TIP
Transfer in progress
Bus
O
17-10
TMS/BKPT
Test mode select/Breakpoint
JTAG
I
17-22
TM[2:0]
Transfer modifier
Bus
O
17-10
TOUT[1:0]
Timer outputs
Timer
O
17-19
TRST/DSCLK
Test reset/Development serial clock
JTAG
I
17-21
TS
Transfer start
Bus
I/O
17-9
TT[1:0]
Transfer type
Bus
O
17-10
TxD[1:0]
Transmit data
Serial module
O
17-18
17.2 MCF5307 Bus Signals
The bus signals provide the external bus interface to the MCF5307.
17.2.1 Address Bus
The address bus provides the address of the byte or most-significant byte (MSB) of the
word or longword being transferred. The address lines also serve as the DRAM addressing,
providing multiplexed row and column address signals. When an external device has
ownership of the MCF5307 bus, the device must drive the address bus and assert TS or AS
to indicate the start of a bus cycle. During an interrupt acknowledge access, A[4:2] indicate
the interrupt level being acknowledged.
17.2.1.1 Address Bus (A[23:0])
The lower 24 bits of the address bus become valid when TS is asserted. A[4:2] indicate the
interrupt level during interrupt acknowledge cycles.
17.2.1.2 Address Bus (A[31:24]/PP[15:8])
These multiplexed pins can serve as the most-significant byte of the address bus, or as the
most-significant byte of the parallel port. Programming the PAR in the system integration
module (SIM) determines the function of each of these eight multiplexed pins. These pins
are programmable on a bit-by-bit basis.
Chapter 17. Signal Descriptions
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MCF5307 Bus Signals
•
•
Freescale Semiconductor, Inc.
A[31:24]—Pins are configured as address bits by setting corresponding PAR bits;
they represent the most-significant address bus bits. As much as 4 Gbytes of
memory are available when all of these pins are programmed as address signals.
PP[15:8]—Pins are configured as parallel port signals by clearing corresponding
PAR bits; these represent the most-significant parallel port bits.
Freescale Semiconductor, Inc...
17.2.2 Data Bus (D[31:0])
The data bus is bidirectional and non-multiplexed. Data is sampled by the MCF5307 on the
rising BCLKO edge. The data bus port width, wait states, and internal termination are
initially defined for the boot chip select by D[7:0] during reset. The port width for each chip
select and DRAM bank are programmable. The data bus uses a default configuration if none
of the chip selects or DRAM bank match the address decode. The default configuration is
a 32-bit port with external termination and burst-inhibited transfers. The data bus can
transfer byte, word, or longword data widths. All 32 data bus signals are driven during
writes, regardless of port width and operand size.
D[7:0] are used during reset initialization as inputs to configure the functions as described
in Table 17-3. They are defined in Section 17.5.5, “Data/Configuration Pins (D[7:0]).”
Table 17-3. Data Pin Configuration
Pin
D7
Function
Auto-acknowledge configuration
(AA_CONFIG)
D[6:5] Port size configuration (PS_CONFIG[1:0])
D4
Section
Section 17.5.5.2, “D7—Auto Acknowledge Configuration
(AA_CONFIG)”
Section 17.5.5.3, “D[6:5]—Port Size Configuration
(PS_CONFIG[1:0])”
Address configuration (ADDR_CONFIG/D4) Section 17.5.6, “D4—Address Configuration
(ADDR_CONFIG)”
D[3:2] Frequency Control PLL (FREQ[1:0])
Section 17.5.7, “D[3:2]—Frequency Control PLL (FREQ[1:0] )
D[1:0] Divide Control (DIVIDE[1:0])
Section 17.5.8, “D[1:0]—Divide Control PCLK to BCLKO
(DIVIDE[1:0])
17.2.3 Read/Write (R/W)
When the MCF5307 is the bus master, it drives the R/W signal to indicate the direction of
subsequent data transfers. It is driven high during read bus cycles and driven low during
write bus cycles. This signal is an input during an external master access.
17.2.4 Size (SIZ[1:0])
When it is the bus master, the MCF5307 outputs these signals to indicate the requested data
transfer size. Table 17-4 shows the definition of the bus request size encodings. When the
MCF5307 device is not the bus master, these signals function as inputs.
Note that for misaligned transfers, SIZ[1:0] indicate the size of each transfer. For example,
if a longword access occurs at a misaligned offset of 0x1, a byte is transferred first (SIZ[1:0]
17-8
MCF5307 User’s Manual
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MCF5307 Bus Signals
= 01), a word is next transferred at offset 0x2 (SIZ[1:0] = 10), then the final byte is
transferred at offset 0x4 (SIZ[1:0] = 01).
For aligned transfers larger than the port size, SIZ[1:0] behaves as follows:
•
•
If bursting is used, SIZ[1:0] stays at the size of transfer.
If bursting is inhibited, SIZ[1:0] first shows the size of the transfer and then shows
the port size.
Table 17-4. Bus Cycle Size Encoding
Freescale Semiconductor, Inc...
SIZ[1:0]
Port Size
00
Longword
01
Byte
10
Word
11
Line
For burst-inhibited transfers, SIZ[1:0] changes with each TS assertion to reflect the next
transfer size. For transfers to port sizes smaller than the transfer size, SIZ[1:0] indicates the
size of the entire transfer on the first access and the size of the current port transfer on
subsequent transfers. For example, for a longword write to an 8-bit port, SIZ[1:0] = 00 for
the first byte transfer and 01 for the next three.
17.2.5 Transfer Start (TS)
The MCF5307 asserts TS during the first clock cycle when address and attributes (TM, TT,
TIP, R/W, and SIZ) are valid. TS is negated in the following clock cycle. When the
MCF5307 is not the bus master, TS is an input.
17.2.6 Address Strobe (AS)
Address strobe (AS) is asserted to indicate when the address is stable at the start of a bus
cycle. The address and attributes are guaranteed to be valid during the entire period that AS
is asserted. This signal is asserted and negated on the falling edge of the clock. When the
MCF5307 is not the bus master, AS is an input.
17.2.7 Transfer Acknowledge (TA)
When the MCF5307 is bus master, the external system drives this input to terminate the bus
transfer. The bus continues to be driven until this synchronous signal is asserted. For write
cycles, the processor continues to drive data one clock after TA is asserted. During read
cycles, the peripheral must continue to drive data until TA is recognized.
If all bus cycles support fast termination, TA can be tied low. However, note that TA cannot
be tied low if potential external bus masters are present. The MCF5307 drives TA for an
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17-9
MCF5307 Bus Signals
Freescale Semiconductor, Inc.
external master access. This condition is indicated by the AM bit in the chip-select mask
register (CSMR) being cleared. See Chapter 10, “Chip-Select Module.”
17.2.8 Transfer In Progress (TIP/PP7)
The TIP/PP7 pin is programmed in the PAR to serve as the transfer-in-progress output or
as a parallel port bits. The TIP output is asserted indicating a bus transfer is in progress. It
is negated during idle bus cycles if the bus is still granted to the processor. It is three-stated
for external master accesses. Note that TIP is held asserted on back-to-back bus cycles.
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17.2.9 Transfer Type (TT[1:0]/PP[1:0])
The TT[1:0]/PP[1:0] pins are programmed in the PAR to serve as the transfer type outputs
or as two parallel port bits. When the MCF5307 is bus master and TT[1:0] are enabled,
these signals are driven as outputs only. If an external master owns the bus and TT[1:0] are
enabled, these pins are three-stated by the MCF5307 and can be driven by the external
master. Table 17-5 shows the definition of the encodings.
Table 17-5. Bus Cycle Transfer Type Encoding
TT[1:0]
Transfer Type
00
Normal access
01
DMA access
10
Emulator access
11
CPU space or interrupt acknowledge
17.2.10 Transfer Modifier (TM[2:0]/PP[4:2])
The TM[2:0]/PP[4:2] pins are programmed in the PAR to serve as the transfer modifier
outputs or as three parallel port bits. These outputs provide supplemental information for
each transfer type; see Table 17-6 through Table 17-10.
When the MCF5307 is the bus master and TM[2:0] are enabled, these signals are driven as
outputs only. If an external device is bus master and TM[2:0] are enabled, these pins are
three-stated by the MCF5307 and can be driven by the external master.
Table 17-6. TM[2:0] Encodings for TT = 00 (Normal Access)
TM[2:0]
000
Cache push access
001
User data access
010
User code access
011–100
101
17-10
Transfer Modifier
Reserved
Supervisor data access
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Table 17-6. TM[2:0] Encodings for TT = 00 (Normal Access) (Continued)
TM[2:0]
Transfer Modifier
110
Supervisor code access
111
Reserved
As shown in Table 17-7, if the DMA is bus master (TT = 01), TM[2:0] indicate the type of
DMA access and provide the DMA acknowledgement information for channels 0 and 1.
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NOTE:
When TT= 01, the TM0 encoding is independent from TM[2:1]
encoding.
Table 17-7. TM0 Encoding for DMA as Master (TT = 01)
TM0
Transfer Modifier Encoding
0
Single-address access negated
1
Single-address access
Table 17-8. TM[2:1] Encoding for DMA as Master (TT = 01)
TM[2:1]
Transfer Modifier Encoding
00
DMA acknowledges negated
01
DMA acknowledge, channel 0
10
DMA acknowledge, channel 1
11
Reserved
Table 17-9 shows TM[2:0] encodings for emulator mode accesses.
Table 17-9. TM[2:0] Encodings for TT = 10 (Emulator Access)
TM[2:0]
000–100
Transfer Modifier
Reserved
101
Emulator mode data access
110
Emulator mode code access
111
Reserved
The TM signals indicate user or data transfer types during emulation transfers, while for
interrupt acknowledge transfers, the TM signals carry the interrupt level being
acknowledged; see Table 17-10.
Table 17-10. TM[2:0] Encodings for TT = 11 (Interrupt Level)
TM[2:0]
Transfer Modifier
000
CPU Space
001
Interrupt level 1 acknowledge
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Interrupt Control Signals
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Table 17-10. TM[2:0] Encodings for TT = 11 (Interrupt Level) (Continued)
TM[2:0]
Transfer Modifier
010
Interrupt level 2 acknowledge
011
Interrupt level 3 acknowledge
100
Interrupt level 4 acknowledge
101
Interrupt level 5 acknowledge
110
Interrupt level 6 acknowledge
111
Interrupt level 7 acknowledge
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17.3 Interrupt Control Signals
The interrupt control signals supply the external interrupt level to the MCF5307 device.
17.3.1 Interrupt Request (IRQ1/IRQ2, IRQ3/IRQ6, IRQ5/IRQ4,
and IRQ7)
The IRQ1, IRQ3, IRQ5, and IRQ7 signals are the default interrupt request signals (IRQn).
However, by setting the appropriate bit in the interrupt port assignment register (IRQPAR),
IRQ1, IRQ3, and IRQ5 can be changed to function as IRQ2, IRQ6, and IRQ4, respectively.
See Section 9.2.4, “Interrupt Port Assignment Register (IRQPAR).”
17.4 Bus Arbitration Signals
The bus arbitration signals provide the external bus arbitration control for the MCF5307.
17.4.1 Bus Request (BR)
The BR output indicates to an external arbiter that the processor is requesting to be bus
master for one or more bus cycles. BR is negated when the MCF5307 begins an access to
the external bus with no other internal accesses pending. BR remains negated until another
internal request occurs.
17.4.2 Bus Grant (BG)
An external arbiter asserts the BG input to indicate that the MCF5307 can take control of
the bus on the next rising edge of BCLKO. When the arbiter negates BG, the MCF5307 will
release the bus as soon as the current transfer completes. The external arbiter must not grant
the bus to any other master until both BD and BG are negated.
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Clock and Reset Signals
17.4.3 Bus Driven (BD)
The MCF5307 asserts BD to indicate that it is the current master and is driving the bus. The
MCF5307 behaves as follows:
•
•
•
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•
If the MCF5307 is the bus master but is not using the bus, BD is asserted.
If the MCF5307 loses mastership during a transfer, it completes the last transfer of
the access, negates BD, and three-states all bus signals on the rising edge of
BCLKO.
If the MCF5307 loses bus mastership during an idle clock cycle, it three-states all
bus signals on the rising edge of BCLKO.
BD cannot be negated unless BG is negated.
17.5 Clock and Reset Signals
The clock and reset signals configure the MCF5307 and provide interface signals to the
external system.
17.5.1 Reset In (RSTI)
Asserting RSTI causes the MCF5307 to enter reset exception processing. When RSTI is
recognized, BR and BD are negated and the address bus, data bus, TT, SIZ, R/W, AS, and
TS are three-stated. RSTO is asserted automatically when RSTI is asserted.
17.5.2 Clock Input (CLKIN)
CLKIN is the MCF5307 input clock frequency to the on-board phase-locked-loop (PLL)
clock generator. CLKIN is used to internally clock or sequence the MCF5307 internal bus
interface at a selected multiple of the input frequency used for internal module logic.
17.5.3 Bus Clock Output (BCLKO)
The internal PLL generates BCLKO and can be programmed to be 1/2, 1/3, or 1/4 of the
processor clock frequency. BCLKO should be used as the bus timing reference.
17.5.4 Reset Out (RSTO)
After RSTI is asserted, the PLL temporarily loses its lock, during which time RSTO is
asserted. When the PLL regains its lock, RSTO negates again. This signal can be used to
reset external devices.
17.5.5 Data/Configuration Pins (D[7:0])
This section describes data pins, D[7:0], that are read at reset for configuration. Table 17-11
shows pin assignments.
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Clock and Reset Signals
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Table 17-11. Data Pin Configuration
Pin
Function
D7
Auto-acknowledge configuration (AA_CONFIG)
D[6:5]
D4
Port size configuration (PS_CONFIG[1:0])
Address configuration (ADDR_CONFIG/D4)
D[3:2]
Frequency Control PLL (FREQ[1:0])
D[1:0]
Divide Control (DIVIDE[1:0])
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17.5.5.1 D[7:5Boot Chip-Select (CS0) Configuration
D[7:5] determine defaults for the global chip select (CS0), the only chip select valid at reset.
These signals correspond to bits in chip-select configuration register 0 (CSCR0).
17.5.5.2 D7—Auto Acknowledge Configuration (AA_CONFIG)
At reset, the enabling and disabling of auto acknowledge for boot CS0 is determined by the
logic level driven on D7 at the rising edge of RSTI. AA_CONFIG is multiplexed with D7
and sampled only at reset. The D7 logic level is reflected as the reset value of CSCR[AA].
Table 17-12 shows how the D7 logic level corresponds to the auto acknowledge timing for
CS0 at reset. Note that auto acknowledge can be disabled by driving a logic 0 on D7 at reset.
Table 17-12. D7 Selection of CS0 Automatic Acknowledge
D7 (CSCR0[AA])
Boot CS0 AA
0
Disabled
1
Enabled with 15 wait states
17.5.5.3 D[6:5]—Port Size Configuration (PS_CONFIG[1:0])
The default port size value of the boot CS0 is determined by the logic levels driven on
D[6:5] at the rising edge of RSTI, which are reflected as the reset value of CSCR[PS]. Table
17-13 shows how the logic levels of D[6:5] correspond to the CS0 port size at reset.
Table 17-13. D6 and D5 Selection of CS0 Port Size
D[6:5] (CSCR0[PS])
Boot CS0 Port Size
00
32-bit port
01
8-bit port
1x
16-bit port
17.5.6 D4—Address Configuration (ADDR_CONFIG)
The address configuration signal (ADDR_CONFIG) programs the PAR of the parallel I/O
port to be either parallel I/O or to be the upper address bus bits along with various attribute
and control signals at reset to give the user the option to access a broader addressing range
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Chip-Select Module Signals
of memory if desired. ADDR_CONFIG is multiplexed with D4 and its configuration is
sampled at reset as shown in Table 17-14.
Table 17-14. D4/ADDR_CONFIG, Address Pin Assignment
D4/ADDR_CONFIG
PAR Configuration at Reset
0
PP[15:0], defaulted to inputs upon reset
1
A[31:24]/TIP/DREQ[1:0]/TM[2:0]/TT[1:0]
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17.5.7 D[3:2]—Frequency Control PLL (FREQ[1:0])
The frequency control PLL input bus (FREQ[1:0]) indicates the CLKIN frequency range.
These signals are multiplexed with D[3:2] and are sampled during the assertion of RESET.
These signals indicate the operating frequency range to the PLL, as shown in Table 17-15.
Note that these signals do not affect the PLL frequency but are required to set up the analog
PLL.
Table 17-15. CLKIN Frequency
FREQ[1:0]/D[3:2]
CLKIN Frequency (MHz)
00
16.6–27.999
01
28–38.999
10
39–45
11
Reserved
17.5.8 D[1:0]—Divide Control PCLK to BCLKO (DIVIDE[1:0])
This 2-bit input bus indicates the BCLKO/PSTCLK ratio. These signals are sampled during
the assertion of RESET and indicate the ratios shown in Table 17-16.
Table 17-16. BCLKO/PSTCLK Divide Ratios
DIVIDE[1:0]/D[1:0]
Ratio of BCLKO/PSTCLK
00
1/4
01
Reserved
10
1/2
11
1/3
17.6 Chip-Select Module Signals
The MCF5307 device provides eight programmable chip-select signals that can directly
interface with SRAM, EPROM, EEPROM, and peripherals. These signals are asserted and
negated on the falling edge of the clock.
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DRAM Controller Signals
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17.6.1 Chip-Select (CS[7:0])
Each chip select can be programmed for a base address location and for masking addresses,
port size and burst-capability indication, wait-state generation, and internal/external
termination.
Reset clears all chip select programming; CS0 is the only chip select initialized out of reset.
CS0 is also unique because it can function at reset as a global chip select that allows boot
ROM to be selected at any defined address space. Port size and termination (internal vs.
external) for boot CS0 are configured by the levels on D[7:5] on the rising edge of RSTI,
as described in Section 17.5.5.1, “D[7:5Boot Chip-Select (CS0) Configuration.”
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The chip-select implementation is described in Chapter 10, “Chip-Select Module.”
17.6.2 Byte Enables/Byte Write Enables (BE[3:0]/BWE[3:0])
The four byte enables are multiplexed with the MCF5307 byte-write-enable signals. Each
pin can be individually programmed through the chip-select control registers (CSCRs). For
each chip select, assertion of byte enables for reads and byte-write enables for write cycles
can be programmed. Alternatively, users can program byte-write enables to assert on writes
and no byte enable assertion for read transfers.
17.6.3 Output Enable (OE)
The output enable (OE) signal is sent to the interfacing memory and/or peripheral to enable
a read transfer. OE is asserted only when a chip select matches the current address decode.
17.7 DRAM Controller Signals
The DRAM signals in the following sections interface to external DRAM. DRAM with
widths of 8, 16, and 32 bits are supported and can access as much as 512 Mbytes of DRAM.
17.7.1 Row Address Strobes (RAS[1:0])
The row address strobes (RAS[1:0]) interface to RAS inputs on industry-standard
ADRAMs. When SDRAMs are used, these signals interface to the chip-select lines of the
SDRAMs within a memory block. Thus, there is one RAS line for each memory block.
17.7.2 Column Address Strobes (CAS[3:0])
The column address strobes (CAS[3:0]) interface to CAS inputs on industry-standard
DRAMs. These provide CAS for a given ADRAM block. When SDRAMs are used, CAS
signals control the byte enables for standard SDRAMs (referred to as DQMx). CAS3
accesses the LSB and CAS0 accesses the MSB of data.
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DMA Controller Module Signals
17.7.3 DRAM Write (DRAMW)
The DRAM write signal (DRAMW) is asserted to signify that a DRAM write cycle is
underway. A read bus cycle is indicated by the negation of DRAMW.
17.7.4 Synchronous DRAM Column Address Strobe (SCAS)
The synchronous DRAM column address strobe (SCAS) is registered during synchronous
mode to route directly to the SCAS signal of SDRAMs.
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17.7.5 Synchronous DRAM Row Address Strobe (SRAS)
The synchronous DRAM row address strobe output (SRAS) is registered during
synchronous mode to route directly to the SRAS signal of external SDRAMs.
17.7.6 Synchronous DRAM Clock Enable (SCKE)
The synchronous DRAM clock enable output (SCKE) is registered during synchronous
mode to route directly to the SCKE signal of external SDRAMs. This signal provides the
clock enable to the SDRAM.
17.7.7 Synchronous Edge Select (EDGESEL)
The synchronous edge select input (EDGESEL) helps select additional output hold times
for signals that interface to external SDRAMs. It provides the following three modes of
operation for SDRAM control signals:
•
•
•
When EDGESEL is tied high, SDRAM control signals change on the rising edge of
BCLKO.
When EDGESEL is tied low, SDRAM control signals change on the falling edge of
BCLKO.
When EDGESEL is tied to the external clock (normally buffered BCLKO), which
drives the SDRAM and other devices, SDRAM signals are generated within the
MCF5307 make a transition on the rising edge of the SDRAM clock. See
Figure 11-14 on page 11-19. This loop-back configuration provides additional
output hold time for MCF5307 interface signals provided to the SDRAM. In this
case, the SDRAM clock operates at the BCLKO frequency, with a possible slight
phase delay.
17.8 DMA Controller Module Signals
The DMA controller module uses the signals in the following subsections to provide
external request for either a source or destination.
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Serial Module Signals
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17.8.1 DMA Request (DREQ[1:0]/PP[6:5])
The DMA request pins (DREQ[1:0]/PP[6:5]) can serve as the DMA request inputs or as
two bits of the parallel port, as determined by individually programmable bits in the PAR.
These inputs are asserted by a peripheral device to request an operand transfer between that
peripheral and memory by either channel 0 or 1 of the on-chip DMA.
Note that DMA acknowledge indication is displayed on TM[2:0], during DMA transfers of
channel 0 and 1.
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17.9 Serial Module Signals
The signals in the following sections are used to transfer serial data between the two UART
modules and external peripherals.
17.9.1 Transmitter Serial Data Output (TxD)
TxD is held high (mark condition) when the transmitter is disabled, idle, or operating in the
local loop-back mode. Data is shifted out least-significant bit (lsb) first on TxD on the
falling edge of the clock source.
17.9.2 Receiver Serial Data Input (RxD)
Data received on RxD is sampled on the rising edge of the clock source, with the lsb
received first.
17.9.3 Clear to Send (CTS)
This input can generate an interrupt on a change of state.
17.9.4 Request to Send (RTS)
This output can be programmed to be negated or asserted automatically by either the
receiver or the transmitter. When connected to a transmitter’s CTS, RTS can control serial
data flow.
17.10 Timer Module Signals
The signals in the following sections are external interfaces to the two general-purpose
MCF5307 timers. These 16-bit timers can capture timer values, trigger external events or
internal interrupts, or count external events.
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Parallel I/O Port (PP[15:0])
17.10.1 Timer Inputs (TIN[1:0])
TIN[1:0] can be programmed as clocks that cause events in the counter and prescalers.
They can also cause captures on the rising edge, falling edge, or both edges.
17.10.2 Timer Outputs (TOUT1, TOUT0)
The programmable timer outputs (TOUT1 and TOUT0) pulse or toggle on various timer
events.
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17.11 Parallel I/O Port (PP[15:0])
This 16-bit bus is dedicated for general-purpose I/O. The parallel port is multiplexed with
the A[31:24], TT[1:0], TM[2:0], TIP, and DREQ[1:0]. These 16 bits are programmed for
functionality with the PAR in the SIM.
The system designer controls the reset value of this register by driving D4 with a 1 or 0 on
the rising edge of RSTI (reset input to MCF5307 device). At reset, the system is configured
as PP[15:0] if D4 is 0; otherwise alternate pin functions selected by PAR = 1 are used.
Motorola recommends that D4 be driven during reset to a logic level.
17.12 I2C Module Signals
The I2C module acts as a two-wire, bidirectional serial interface between the MCF5307 and
peripherals with an I2C interface (such as LED controller, A-to-D converter, or D-to-A
converter). Devices connected to the I2C must have open-drain or open-collector outputs.
17.12.1 I2C Serial Clock (SCL)
The bidirectional, open-drain I2C serial clock signal (SCL) is the clock signal for I2C
module operation. The I2C module controls this signal when the bus is in master mode; all
I2C devices drive this signal to synchronize I2C timing.
17.12.2 I2C Serial Data (SDA)
The bidirectional, open-drain I2C serial data signal (SDA) is the data input/output for the
serial I2C interface.
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Debug and Test Signals
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17.13 Debug and Test Signals
The signals in this section interface with external I/O to provide processor status signals.
17.13.1 Test Mode (MTMOD[3:0])
The test mode signals choose between multiplexed debug module and JTAG signals. If
MTMOD0 is low, the part is in normal and background debug mode (BDM); if it is high,
it is in normal and JTAG mode. All other MTMOD values are reserved; MTMOD[3:1]
should be tied to ground and MTMOD[3:0] should not be changed while RSTI is negated.
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17.13.2 High Impedance (HIZ)
The assertion of HIZ forces all output drivers to high-impedance state. The timing on HIZ
is independent of the clock. Note that HIZ does not override the JTAG operation;
TDO/DSO can be forced to high impedance by asserting TRST.
17.13.3 Processor Clock Output (PSTCLK)
The internal PLL generates this output signal, and is the processor clock output that is used
as the timing reference for the debug bus timing (DDATA[3:0] and PST[3:0]). PSTCLK is
at the same frequency as the core processor and cache memory. The frequency is 2x the
CLKIN.
17.13.4 Debug Data (DDATA[3:0])
The debug data signals (DDATA[3:0]) display captured processor data and breakpoint
status. See Chapter 5, “Debug Support,” for additional information on this bus.
17.13.5 Processor Status (PST[3:0])
The processor status pins indicate the MCF5307 processor status. During debug mode, the
timing is synchronous with the processor clock (PSTCLK) and the status is not related to
the current bus transfer. Table 2-11 shows the encodings of these signals.
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Debug Module/JTAG Signals
.
Table 17-17. Processor Status Signal Encodings
PST[3:0]
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Definition
1
2
Hex
Binary
0x0
0000
Continue execution
0x1
0001
Begin execution of an instruction
0x2
0010
Reserved
0x3
0011
Entry into user-mode
0x4
0100
Begin execution of PULSE and WDDATA instructions
0x5
0101
Begin execution of taken branch or Synch_PC1
0x6
0110
Reserved
0x7
0111
Begin execution of RTE instruction
0x8
1000
Begin 1-byte data transfer on DDATA
0x9
1001
Begin 2-byte data transfer on DDATA
0xA
1010
Begin 3-byte data transfer on DDATA
0xB
1011
Begin 4-byte data transfer on DDATA
0xC
1100
Exception processing2
0xD
1101
Emulator mode entry exception processing2
0xE
1110
Processor is stopped, waiting for interrupt2
0xF
1111
Processor is halted2
Rev. B enhancement.
These encodings are asserted for multiple cycles.
17.14 Debug Module/JTAG Signals
The MCF5307 complies with the IEEE 1149.1a JTAG testing standard. JTAG test pins are
multiplexed with background debug pins. Except for TCK, these signals are selected by the
value of MTMOD0. If MTMOD0 is high, JTAG signals are chosen; if it is low, debug
module signals are chosen. MTMOD0 should be changed only while RSTI is asserted.
17.14.1 Test Reset/Development Serial Clock
(TRST/DSCLK)
If MTMOD0 is high, TRST is selected. TRST asynchronously resets the internal JTAG
controller to the test logic reset state, causing the JTAG instruction register to choose the
bypass instruction. When this occurs, JTAG logic is benign and does not interfere with
normal MCF5307 functionality.
Although TRST is asynchronous, Motorola recommends that it makes an
asserted-to-negated transition only while TMS is held high. TRST has an internal pull-up
resistor so if it is not driven low, it defaults to a logic level of 1. If TRST is not used, it can
be tied to ground or, if TCK is clocked, to VDD. Tying TRST to ground places the JTAG
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Debug Module/JTAG Signals
controller in test logic reset state immediately. Tying it to VDD causes the JTAG controller
(if TMS is a logic level of 1) to eventually enter test logic reset state after 5 TCK clocks.
If MTMOD0 is low, DSCLK is selected. DSCLK is the development serial clock for the
serial interface to the debug module. The maximum DSCLK frequency is 1/5 CLKIN. See
Chapter 5, “Debug Support.”
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17.14.2 Test Mode Select/Breakpoint (TMS/BKPT)
If MTMOD0 is high, TMS is selected. The TMS input provides information to determine
the JTAG test operation mode. The state of TMS and the internal 16-state JTAG controller
state machine at the rising edge of TCK determine whether the JTAG controller holds its
current state or advances to the next state. This directly controls whether JTAG data or
instruction operations occur. TMS has an internal pull-up resistor so that if it is not driven
low, it defaults to a logic level of 1. But if TMS is not used, it should be tied to VDD.
If MTMOD0 is low, BKPT is selected. BKPT signals a hardware breakpoint to the
processor in debug mode. See Chapter 5, “Debug Support.”
17.14.3 Test Data Input/Development Serial Input (TDI/DSI)
If MTMOD0 is high, TDI is selected. TDI provides the serial data port for loading the
various JTAG boundary scan, bypass, and instruction registers. Shifting in data depends on
the state of the JTAG controller state machine and the instruction in the instruction register.
Shifts occur on the TCK rising edge. TDI has an internal pull-up resistor, so when not
driven low it defaults to high. But if TDI is not used, it should be tied to VDD.
If MTMOD0 is low, DSI is selected. DSI provides the single-bit communication for debug
module commands. See Chapter 5, “Debug Support.”
17.14.4 Test Data Output/Development Serial Output
(TDO/DSO)
If MTMOD0 is high, TDO is selected. The TDO output provides the serial data port for
outputting data from JTAG logic. Shifting out data depends on the JTAG controller state
machine and the instruction in the instruction register. Data shifting occurs on the falling
edge of TCK. When TDO is not outputting test data, it is three-stated. TDO can be
three-stated to allow bused or parallel connections to other devices having JTAG.
If MTMOD0 is low, DSO is selected. DSO provides single-bit communication for debug
module responses. See Chapter 5, “Debug Support.”
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Debug Module/JTAG Signals
17.14.5 Test Clock (TCK)
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TCK is the dedicated JTAG test logic clock independent of the MCF5307 processor clock.
Various JTAG operations occur on the rising or falling edge of TCK. Holding TCK high or
low for an indefinite period does not cause JTAG test logic to lose state information. If TCK
is not used, it must be tied to ground.
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Debug Module/JTAG Signals
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Chapter 18
Bus Operation
This chapter describes data-transfer operations, error conditions, bus arbitration, and reset
operations. It describes transfers initiated by the MCF5307 and by an external bus master,
and includes detailed timing diagrams showing the interaction of signals in supported bus
operations. Chapter 11, “Synchronous/Asynchronous DRAM Controller Module,”
describes DRAM cycles.
18.1 Features
The following list summarizes bus operation features:
•
•
•
•
•
•
•
Up to 32 bits of address and data
8-, 16-, and 32-bit port sizes
Byte, word, longword, and line size transfers
Bus arbitration for external devices
Burst and burst-inhibited transfer support
Internal termination for core and DMA bus cycles
External termination of bus cycles controlled by an external bus master
Note that, throughout this manual, an overbar indicates an active-low signal.
18.2 Bus and Control Signals
Table 18-1 summarizes MCF5307 bus signals described in Chapter 17, “Signal
Descriptions.”
Table 18-1. ColdFire Bus Signal Summary
Signal Name
AS
A[31:0]
BE/BWE 1
CS[7:0]
1
D[31:0]
Description
MCF5307 Master
External Master
Edge
Address strobe
O
I
Falling
Address bus
O
I
Rising
Byte enable/Byte write enable
O
O
Falling
Chip selects
O
O
Falling
Data bus
I/O
I/O
Rising
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Bus Characteristics
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Table 18-1. ColdFire Bus Signal Summary (Continued)
Signal Name
IRQ[7,5,3,1]
External Master
Edge
Interrupt request
I
I
Rising
Output enable
O
I
Falling
R/W
Read/write
O
I
Rising
Transfer size
O
I
Rising
TA
Transfer acknowledge
I
O
Rising
TIP
Transfer in progress
O
Three-state
Rising
Transfer modifier
O
Three-state
Rising
TS
Transfer start
O
I
Rising
TT[1:0]
Transfer type
O
Three-state
Rising
TM[2:0]
Freescale Semiconductor, Inc...
MCF5307 Master
OE 1
SIZ[1:0]
1
Description
These signals change after the falling edge. In Chapter 20, “Electrical Specifications,” these signals are specified
off the rising edge because CLKIN is squared up internally.
18.3 Bus Characteristics
The MCF5307 uses an input clock signal (CLKIN) to generate its internal clock. BCLKO
is the bus clock rate, where all bus operations are synchronous to the rising edge of
BCLKO. Some of the bus control signals (BE/BWE, OE, CSx, and AS) are synchronous to
the falling edge, shown in Figure 18-1. Bus characteristics may differ somewhat for
interfacing with external DRAM.
BCLKO
tvo
tho
Rising-Edge
Signals
tvo
Falling-Edge
Signals
tsi
thi
Inputs
tvo=Propagation delay of signal relative to BCLKO edge
tho=Output hold time relative to BCLKO edge
tsi =Required input setup time relative to BCLKO edge
thi=Required input hold time relative to BCLKO edge
Figure 18-1. Signal Relationship to BCLKO for Non-DRAM Access
18-2
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tho
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Data Transfer Operation
18.4 Data Transfer Operation
Data transfers between the MCF5307 and other devices involve the following signals:
Freescale Semiconductor, Inc...
•
•
•
•
•
Address bus (A[31:0])
Data bus (D[31:0])
Control signals (TS and TA)
AS, CSx, OE, BE/BWE
Attribute signals (R/W, SIZ, TT, TM, and TIP)
The address bus, write data, TS, and all attribute signals change on the rising edge of
BCLKO. Read data is latched into the MCF5307 on the rising edge of BCLKO. AS, CSx,
OE, and BE/BWE change on the falling edge.
The MCF5307 bus supports byte, word, and longword operand transfers and allows
accesses to 8-, 16-, and 32-bit data ports. Transfer parameters such as port size, the number
of wait states for the external slave being accessed, and whether internal transfer
termination is enabled, can be programmed in the chip-select control registers (CSCRs) and
DRAM control registers (DACRs).
For aligned transfers larger than the port size, SIZ[1:0] behaves as follows:
•
•
If bursting is used, SIZ[1:0] stays at the size of transfer.
If bursting is inhibited, SIZ[1:0] first shows the size of the transfer and then shows
the port size.
Table 18-2 shows encoding for SIZ[1:0].
Table 18-2. Bus Cycle Size Encoding
SIZ[1:0]
Port Size
00
Longword
01
Byte
10
Word
11
Line
Figure 18-2 shows the byte lanes that external memory should be connected to and the
sequential transfers if a longword is transferred for three port sizes. For example, an 8-bit
memory should be connected to D[31:24] (BE0). A longword transfer takes four transfers
on D[31:24], starting with the MSB and going to the LSB.
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Data Transfer Operation
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BE1
BE2
BE3
D[31:24]
D[23:16]
D[15:8]
D[7:0]
32-Bit Port
Memory
Byte 0
Byte 1
Byte 2
Byte 3
16-Bit Port
Memory
Byte 0
Byte 1
Byte 2
Byte 3
Byte Enable
Processor
External
Data Bus
8-Bit Port
Memory
BE0
Driven with
indeterminate values
Byte 0
Byte 1
Byte 2
Driven with
indeterminate values
Freescale Semiconductor, Inc...
Byte 3
Figure 18-2. Connections for External Memory Port Sizes
The timing relationships between BCLKOchip select (CS[7:0]), byte enable/byte write
enables (BE/BWE[3:0]), and output enable (OE) are similar to their relationships with
address strobe (AS) in that all transitions occur during the low phase of BCLKO. However,
as shown in Figure 18-3, differences in on-chip signal routing and external loading may
prevent signals from asserting simultaneously.
BCLKO
CS[7:0]
BE/BWE[3:0]
AS, OE
Figure 18-3. Chip-Select Module Output Timing Diagram
18.4.1 Bus Cycle Execution
When a bus cycle is initiated, the MCF5307 first compares its address with the base address
and mask configurations programmed for chip selects 0–7 (CSCR0–CSCR7) and for
DRAM blocks 0 and 1 address and control registers (DACR0 and DACR1). If the driven
address matches a programmed chip select or DRAM block, the appropriate chip select is
asserted or the DRAM block is selected using the specifications programmed in the
respective configuration register. Otherwise, the following occurs:
•
•
•
18-4
If the address and attributes do not match in CSCR or DACR, the MCF5307 runs an
external burst-inhibited bus cycle with a default of external termination on a 32-bit
port.
If an address and attribute match in multiple CSCRs, the matching chip-select
signals are driven; however, the MCF5307 runs an external burst-inhibited bus cycle
with external termination on a 32-bit port.
If an address and attribute match both DACRs or a DACR and a CSCR, the operation
is undefined.
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Data Transfer Operation
Table 18-3 shows the type of access as a function of match in the CSCRs and DACRs.
Table 18-3. Accesses by Matches in CSCRs and DACRs
Freescale Semiconductor, Inc...
Number of CSCR Matches
Number of DACR Matches
Type of Access
0
0
External
Defined by CSCRs
1
0
Multiple
0
External, burst-inhibited, 32-bit
0
1
Defined by DACRs
1
1
Undefined
Multiple
1
Undefined
0
Multiple
Undefined
1
Multiple
Undefined
Multiple
Multiple
Undefined
Basic bus operations occur in three clocks, as follows:
1. During the first clock, the address, attributes, and TS are driven. AS is asserted at the
falling edge of the clock to indicate that address and attributes are valid and stable.
2. Data and TA are sampled during the second clock of a bus-read cycle. During a read,
the external device provides data and is sampled at the rising edge at the end of the
second bus clock. This data is concurrent with TA, which is also sampled at the
rising clock edge.
During a write, the MCF5307 drives data from the rising clock edge at the end of the
first clock to the rising clock edge at the end of the bus cycle. Wait states can be
added between the first and second clocks by delaying the assertion of TA. TA can
be configured to be generated internally through the DACRs and CSCRs. If TA is
not generated internally, the system must provide it externally.
3. The last clock of the bus cycle uses what would be an idle clock between cycles to
provide hold time for address, attributes, and write data. Figure 18-6 and
Figure 18-8 show the basic read and write operations.
18.4.2 Data Transfer Cycle States
The data transfer operation in the MCF5307 is controlled by an on-chip state machine. Each
bus clock cycle is divided into two states. Even states occur when BCLKO is high and odd
states occur when BCLKO is low. The state transition diagram for basic and
fast-termination read and write cycles is shown in Figure 18-4.
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Data Transfer Operation
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Next Cycle
S0
S5
S1
Basic
Read/Write
Fast
Termination
S4
S2
Wait
States
Freescale Semiconductor, Inc...
S3
Figure 18-4. Data Transfer State Transition Diagram
Table 18-4 describes the states as they appear in subsequent timing diagrams. Note that the
TT[1:0], TM[2:0], and TIP functions are chosen in the PAR, as described in Section 15.1.1,
“Pin Assignment Register (PAR).”
Table 18-4. Bus Cycle States
State
Cycle
BCLKO
Description
S0
All
High
The read or write cycle is initiated. On the rising edge of BCLKO, the MCF5307
places a valid address on the address bus, asserts TIP, and drives R/W high for
a read and low for a write, if these signals are not already in the appropriate
state. The MCF5307 asserts TT[1:0], TM[2:0], SIZ[1:0], and TS on the rising
edge of BCLKO.
S1
All
Low
AS asserts on the falling edge of BCLKO, indicating that the address and
attributes are stable. The appropriate CSx, BE/BWE, and OE signals assert on
the BCLKO falling edge.
Fast termination
S2
Read/write
(skipped for fast
termination)
TA must be asserted during S1. Data is made available by the external device
and is sampled on the rising edge of BCLKO with TA asserted.
High
Write
S3
Read/write
(skipped for fast
termination)
The data bus is driven out of high impedance as data is placed on the bus on
the rising edge of BCLKO.
Low
Read
S4
All
Read (including
fast termination)
18-6
TS is negated on the rising edge of BCLKO.
The MCF5307 waits for TA assertion. If TA is not sampled as asserted before
the rising edge of BCLKO at the end of the first clock cycle, the MCF5307
inserts wait states (full clock cycles) until TA is sampled as asserted.
Data is made available by the external device on the falling edge of BCLKO and
is sampled on the rising edge of BCLKO with TA asserted.
High
The external device should negate TA.
The external device can stop driving data after the rising edge of BCLKO.
However, data could be driven up to S5.
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Data Transfer Operation
Table 18-4. Bus Cycle States (Continued)
State
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S5
Cycle
BCLKO
S5
Low
Description
AS, CS, BE/BWE, and OE are negated on the BCLKO falling edge. The
MCF5307 stops driving address lines and R/W on the rising edge of BCLKO,
terminating the read or write cycle. At the same time, the MCF5307 negates
TT[1:0], TM[2:0], TIP, and SIZ[1:0] on the rising edge of BCLKO.
Note that the rising edge of BCLKO may be the start of S0 for the next access
cycle; in this case, TIP remains asserted and R/W may not transition,
depending on the nature of the back-to-back cycles.
Read
The external device stops driving data between S4 and S5.
Write
The data bus returns to high impedance on the rising edge of BCLKO. The
rising edge of BCLKO may be the start of S0 for the next access.
NOTE:
An external device has at most two BCLKO cycles after the
start of S4 to three-state the data bus after data is sampled in S3.
This applies to basic read cycles, fast-termination cycles, and
the last transfer of a burst.
18.4.3 Read Cycle
During a read cycle, the MCF5307 receives data from memory or from a peripheral device.
Figure 18-5 is a read cycle flowchart.
System
MCF5307
1.
Set R/W to read
2.
Place address on A[31:0]
3.
Assert TT[1:0], TM[2:0], TIP,
and SIZ[1:0]
4.
Assert TS
5.
Assert AS
6.
Negate TS
1.
1.
1.
Decode address and select the
appropriate slave device.
2.
Drive data on D[31:0]
3.
Assert TA
1.
Negate TA.
2.
Stop driving D[31:0]
Sample TA low and latch data
Start next cycle
Figure 18-5. Read Cycle Flowchart
The read cycle timing diagram is shown in Figure 18-6.
NOTE:
In the following timing diagrams, TA waveforms apply for chip
selects programmed to enable either internal or external
termination. TA assertion should look the same in either case.
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Data Transfer Operation
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S0
S1
S2
S3
S4
S5
BCLKO
R/W
TT[1:0], TM[2:0]
SIZ[1:0], A[31:0]
TIP
TS
Freescale Semiconductor, Inc...
AS, CSx
BEx, OE
Read
D[31:0]
TA
Figure 18-6. Basic Read Bus Cycle
Note the following characteristics of a basic read:
•
•
•
In S3, data is made available by the external device on the falling edge of BCLKO
and is sampled on the rising edge of BCLKO with TA asserted.
In S4, the external device can stop driving data after the rising edge of BCLKO.
However, data could be driven up to S5.
For a read cycle, the external device stops driving data between S4 and S5.
States are described in Table 18-4.
18.4.4 Write Cycle
During a write cycle, the MCF5307 sends data to memory or to a peripheral device. The
write cycle flowchart is shown in Figure 18-7.
18-8
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Data Transfer Operation
System
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MCF5307
1.
Set R/W to write
2.
Place address on A[31:0]
3.
Assert TT[1:0], TM[2:0], TIP,
and SIZ[1:0]
4.
Assert TS
5.
Assert AS
6.
Place data on D[31:0]
7.
Negate TS
1.
Sample TA low
1.
Tree-state D[31:0]
2.
Start next cycle
1.
Decode address
2.
Store data on D[31:0]
3.
Assert TA
1.
Negate TA
Figure 18-7. Write Cycle Flowchart
The write cycle timing diagram is shown in Figure 18-8.
S0
S1
S2
S3
S4
S5
BCLKO
A[31:0], TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
AS, CSx
BWEx
Write
D[31:0]
TA
Figure 18-8. Basic Write Bus Cycle
Table 18-4 describes the six states of a basic write cycle.
18.4.5 Fast-Termination Cycles
Two clock-cycle transfers are supported on the MCF5307 bus. In most cases, this is
impractical to use in a system because the termination must take place in the same half
clock during which AS is asserted. Because this is atypical, it is not referred to as the
zero-wait-state case but is called the fast-termination case. A fast-termination cycle is one
in which an external device or memory asserts TA as soon as TS is detected. This means
that the MCF5307 samples TA on the rising edge of the second cycle of the bus transfer.
Figure 18-9 shows a read cycle with fast termination. Note that fast termination cannot be
used with internal termination.
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Data Transfer Operation
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S0
S1
S4
S5
BCLKO
A[31:0],TT[1:0]
TM[2:0, SIZ[1:0]]
R/W
TIP
TS
AS, CSx
BEx, OE
Read
Freescale Semiconductor, Inc...
D[31:0]
TA
Figure 18-9. Read Cycle with Fast Termination
Figure 18-10 shows a write cycle with fast termination.
S0
S1
S4
S5
BCLKO
A[31:0], TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
AS, CSx
BWEx, OE
D[31:0]
Write
TA
Figure 18-10. Write Cycle with Fast Termination
18.4.6 Back-to-Back Bus Cycles
The MCF5307 runs back-to-back bus cycles whenever possible. For example, when a
longword read is started on a word-size bus, the processor performs two back-to-back word
read accesses. Back-to-back accesses are distinguished by the continuous assertion of TIP
throughout the cycle. Figure 18-11 shows a read back-to-back with a write.
18-10
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Data Transfer Operation
S0
S1
S2
S3
S4
S5
S0
S1
S2
S3
S4
S5
BCLKO
A[31:0], TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
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AS, CSx
BE/BWEx
OE
Read
D[31:0]
Write
TA
Figure 18-11. Back-to-Back Bus Cycles
Basic read and write cycles are used to show a back-to-back cycle, but there is no restriction
as to the type of operations to be placed back to back. The initiation of a back-to-back cycle
is not user definable.
18.4.7 Burst Cycles
The MCF5307 can be programmed to initiate burst cycles if its transfer size exceeds the
size of the port it is transferring to. For example, with bursting enabled, a word transfer to
an 8-bit port would take a 2-byte burst cycle for which SIZ[1:0] = 10 throughout. A line
transfer to a 32-bit port would take a 4-longword burst cycle, for which SIZ[1:0] = 11
throughout.
The MCF5307 bus can support 2-1-1-1 burst cycles to maximize cache performance and
optimize DMA transfers. A user can add wait states by delaying termination of the cycle.
The initiation of a burst cycle is encoded on the size pins. For burst transfers to smaller port
sizes, SIZ[1:0] indicates the size of the entire transfer. For example, if the MCF5307 writes
a longword to an 8-bit port, SIZ[1:0] = 00 for the first byte transfer and does not change.
CSCRs are used to enable bursting for reads, writes, or both. MCF5307 memory space can
be declared burst-inhibited for reads and writes by clearing the appropriate
CSCRx[BSTR,BSTW]. A line access to a burst-inhibited region is broken into separate
port-width accesses. Unlike a burst access, SIZ[1:0] = 11 only for the first port-width
access; for the remaining accesses, SIZ[1:0] reflects the port width, with individual
accesses separated by AS negations. The address changes if internal termination is used but
does not change if external termination is used, as shown in Figure 18-12 and Figure 18-14.
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18.4.7.1 Line Transfers
A line is a 16-byte-aligned, 16-byte value. Despite the alignment, a line access may not
begin on the aligned address; therefore, the bus interface supports line transfers on multiple
address boundaries. Table 18-5 shows allowable patterns for line accesses.
Freescale Semiconductor, Inc...
Table 18-5. Allowable Line Access Patterns
A[3:2]
Longword Accesses
00
0–4–8–C
01
4–8–C–0
10
8–C–0–4
11
C–0–4–8
18.4.7.2 Line Read Bus Cycles
Figure 18-12 shows line read with zero wait states. The access starts like a basic read bus
cycle with the first data transfer sampled on the rising edge of S4, but the next pipelined
burst data is sampled a cycle later on the rising edge of S6. Each subsequent pipelined data
burst is single cycle until the last one, which can be held for up to 2 BCLKO cycles after
TA is asserted. Note that AS and CSx are asserted throughout the burst transfer. This
example shows the timing for external termination, which differs only from the internal
termination example in Figure 18-13 in that the address lines change only at the beginning
(assertion of TS and TIP) and end (negation of TIP) of the transfer.
S0
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10 S11 S12
BCLKO
A[31:0], TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
AS, CSx
BE/BWEx, OE
D[31:0]
Read
Read
Read
Read
TA
Figure 18-12. Line Read Burst (2-1-1-1), External Termination
Figure 18-13 shows timing when internal termination is used.
18-12
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Data Transfer Operation
S0
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10 S11 S12
BCLKO
A[31:0]
TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
Freescale Semiconductor, Inc...
AS, CSx
BE/BWEx, OE
Read
D[31:0]
Read
Read
Read
TA
Figure 18-13. Line Read Burst (2-1-1-1), Internal Termination
Figure 18-14 shows a line access read with one wait state programmed in CSCRx to give
the peripheral or memory more time to return read data. This figure follows the same
execution as a zero-wait state read burst with the exception of an added wait state.
.
S0 S1 S2 S3
WS
S4 S5
WS
S6 S7
WS
S8 S9
WS
S10S11S12S13
BCLKO
A[31:0], TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
AS, CSx
BE/BWEx, OE
D[31:0]
Read
Read
Read
Read
TA
Figure 18-14. Line Read Burst (3-2-2-2), External Termination
Figure 18-15 shows a burst-inhibited line read access with fast termination. The external
device executes a basic read cycle while determining that a line is being transferred. The
external device uses fast termination for subsequent transfers.
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Data Transfer Operation
S0
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S1
S2 S3 S4 S5 S0 S1 S4 S5
S0 S1 S4 S5
S0 S1 S4 S5
A[3:2] = 10
A[3:2] = 11
S6 S7
BCLKO
A[3:2] = 00
A[31:0]
A[3:2] = 01
R/W
TT[1:0]
TM[2:0]
TIP
SIZ[1:0]
Line
Longword
Freescale Semiconductor, Inc...
TS
AS, CSx
BE/BWEx, OE
D[31:0]
Read
Read
Read
Read
Fast
Fast
Fast
TA
Basic
Figure 18-15. Line Read Burst-Inhibited, Fast, External Termination
18.4.7.3 Line Write Bus Cycles
Figure 18-16 shows a line access write with zero wait states. It begins like a basic write bus
cycle with data driven one clock after TS. The next pipelined burst data is driven a cycle
after the write data is registered (on the rising edge of S6). Each subsequent burst takes a
single cycle. Note that as with the line read example in Figure 18-12, AS and CSx remain
asserted throughout the burst transfer. This example shows the behavior of the address lines
for both internal and external termination. Note that with external termination, address
lines, like SIZ, TT, and TM, hold the same value for the entire transfer.
S0
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
BCLKO
A[31:0]
Internal Termination
A[31:0]
External Termination
SIZ[1:0]
TM[1:0], TT[1:0]
R/W, TIP
TS
AS, CSx
OE, BE/BWE
D[31:0]
Write
Write
Write
Write
TA
Figure 18-16. Line Write Burst (2-1-1-1), Internal/External Termination
18-14
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Data Transfer Operation
Figure 18-17 shows a line burst write with one wait-state insertion.
S0 S1 S2 S3
WS
S4 S5
WS
S6 S7
WS
S8 S9
WS
S10S11
BCLKO
A[31:0]
R/W, TIP
TM[2:0], TT[1:0]
SIZ[1:0]
TS
Freescale Semiconductor, Inc...
AS, CSx
OE, BWE
Write
D[31:0]
Write
Write
Write
TA
Figure 18-17. Line Write Burst (3-2-2-2) with One Wait State, Internal Termination
Figure 18-18 shows a burst-inhibited line write. The external device executes a basic write
cycle while determining that a line is being transferred. The external device uses fast
termination to end each subsequent transfer.
S0
S1
S2 S3 S4 S5 S0 S1 S4 S5
S0 S1 S4 S5
S0 S1 S4 S5
A[3:2] = 10
A[3:2] = 11
BCLKO
A[31:0]
A[3:2] = 00
A[3:2] = 01
R/W, TIP
TT[1:0]
TM[2:0]
SIZ[1:0]
Longword
Line
TS
AS, CSx
OE, BWE
D[31:0]
Write
Write
Write
Write
TA
Basic
Fast
Fast
Fast
Figure 18-18. Line Write Burst-Inhibited, Internal Termination
18.4.7.4 Transfers Using Mixed Port Sizes
Figure 18-19 shows timing for a longword read from an 8-bit port using external
termination. Figure 18-20 shows the same transfer with internal termination. For both,
SIZ[1:0] change only at the start of a new transfer because this burst is implemented as one
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18-15
Misaligned Operands
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transfer.
S0
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10 S11 S12
BCLKO
A[31:0], TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
Freescale Semiconductor, Inc...
AS, CSx
BE/BWEx, OE
Read
Read
D[31:0]
Read
Read
TA
Figure 18-19. Longword Read from an 8-Bit Port, External Termination
Note that with external termination, address signals do not change. With internal
termination, Figure 18-20, A[1:0] increment for the same longword transfer.
S0
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10 S11 S12
BCLKO
A[1:0]
A[31:2], TT[1:0]
TM[2:0], SIZ[1:0]
R/W
TIP
TS
AS, CSx
BE/BWEx, OE
D[31:0]
Read
Read
Read
Read
TA
Figure 18-20. Longword Read from an 8-Bit Port, Internal Termination
18.5 Misaligned Operands
Because operands, unlike opcodes, can reside at any byte boundary, they are allowed to be
misaligned. A byte operand is properly aligned at any address, a word operand is
misaligned at an odd address, and a longword is misaligned at an address not a multiple of
four. Although the MCF5307 enforces no alignment restrictions for data operands
(including program counter (PC) relative data addressing), additional bus cycles are
required for misaligned operands.
18-16
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Bus Errors
Instruction words and extension words (opcodes) must reside on word boundaries.
Attempting to prefetch a misaligned instruction word causes an address error exception.
The MCF5307 converts misaligned, cache-inhibited operand accesses to multiple aligned
accesses. Figure 18-21 shows the transfer of a longword operand from a byte address to a
32-bit port. In this example, SIZ[1:0] specify a byte transfer and a byte offset of 0x1. The
slave device supplies the byte and acknowledges the data transfer. When the MCF5307
starts the second cycle, SIZ[1:0] specify a word transfer with a byte offset of 0x2. The next
two bytes are transferred in this cycle. In the third cycle, byte 3 is transferred. The byte
offset is now 0x0, the port supplies the final byte, and the operation is complete.
Freescale Semiconductor, Inc...
31
24 23
16 15
87
0
A[2:0]
Transfer 1
—
Byte 0
—
—
001
Transfer 2
—
—
Byte 1
Byte 2
010
Transfer 3
Byte 3
—
—
—
100
Figure 18-21. Example of a Misaligned Longword Transfer (32-Bit Port)
If an operand is cacheable and is misaligned across a cache-line boundary, both lines are
loaded into the cache. The example in Figure 18-22 differs from the one in Figure 18-21 in
that the operand is word-sized and the transfer takes only two bus cycles.
31
24 23
16 15
87
0
A[2:0]
Transfer 1
—
—
—
Byte 0
001
Transfer 2
Byte 0
—
—
—
100
Figure 18-22. Example of a Misaligned Word Transfer (32-Bit Port)
NOTE:
External masters using internal MCF5307 chip selects and
default memory control signals must initiate aligned transfers.
18.6 Bus Errors
The MCF5307 has no bus monitor. If the auto-acknowledge feature is not enabled for the
address that generates the error, the bus cycle can be terminated by asserting TA or by using
the software watchdog timer. If it is required that the MCF5307 handle a bus error
differently, an interrupt handler can be invoked by asserting an interrupt to the core along
with TA when the bus error occurs.
18.7 Interrupt Exceptions
A peripheral device uses the interrupt-request signals (IRQx) to signal the core to take an
interrupt exception when it needs the MCF5307 or is ready to send information to it. The
interrupt transfers control to an appropriate routine.
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Interrupt Exceptions
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The MCF5307 has the following two levels of interrupt masking:
•
•
Interrupt mask registers in the SIM compare interrupt inputs with programmable
interrupt mask levels. The SIM outputs only unmasked interrupts.
The status register uses a 3-bit interrupt priority mask. The core recognizes only
interrupt requests of higher priority than the value in the mask. See Section 2.2.2.1,
“Status Register (SR).”
Freescale Semiconductor, Inc...
NOTE:
To mask a level 1–6 interrupt source, write a higher-level SR
interrupt mask before setting IMR. Then restore the mask to its
previous value. Do not mask a level 7 interrupt source.
The MCF5307 continuously samples and synchronizes external interrupt inputs. An
interrupt request must be held for at least two consecutive BCLKO periods to be considered
valid. To guarantee that the interrupt is recognized, the request level must be maintained
until the MCF5307 acknowledges the interrupt with an interrupt-acknowledge cycle.
NOTE:
Interrupt levels 1–7 are level-sensitive. Level 7 is also
edge-triggered. See Section 18.7.1, “Level 7 Interrupts.”
The MCF5307 takes an interrupt exception for a pending interrupt within one instruction
boundary after processing any higher-priority pending exception. Thus, the MCF5307
executes at least one instruction in an interrupt exception handler before recognizing
another interrupt request.
If autovector generation is used for internal interrupts (ICRn[AVEC] = 1), the interrupt
acknowledge vector is generated internally and no interrupt acknowledge cycle is generated
on the external bus.
If autovector generation is used for external interrupts, no interrupt acknowledge cycle is
shown on the external bus (AS is not asserted) unless AVR[BLK] is 0. Consequently, the
external interrupt must be cleared in the interrupt service routine. See Section 9.2.2,
“Autovector Register (AVR).”
18.7.1 Level 7 Interrupts
Level 7 interrupts are nonmaskable and are handled differently than other interrupts.
Level 7 interrupts are edge triggered by a transition from a lower priority request to the
level 7 request. Interrupts at all other levels are level sensitive. Therefore, if IRQ7 remains
asserted, the MCF5307 recognizes only one level 7 interrupt because only one transition
from a lower level request to a level 7evel 7 request occurred. For the processor to
recognize two consecutive level 7 interrupts, one of the following must occur:
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•
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•
Interrupt Exceptions
The interrupt request on the interrupt control pins is raised to level 7 and stays there
until an interrupt-acknowledge cycle begins. The level later drops but then returns to
level 7, causing a second transition on the interrupt control lines.
The interrupt request on the interrupt control pins is raised to level 7 and stays there.
If the level 7 interrupt routine lowers the mask level, a second level 7 interrupt is
recognized without a transition of the interrupt control pins. After the level 7 routine
completes, the MCF5307 compares the mask level to the request level on the IRQx
signals. Because the mask level is lower than the requested level, the interrupt mask
is set back to level 7. To ensure it is recognized, the level 7 request on IRQ7 must be
held until the second interrupt-acknowledge bus cycle begins.
18.7.2 Interrupt-Acknowledge Cycle
When the MCF5307 processes an interrupt exception, it performs an interruptacknowledge bus cycle to obtain the vector number that contains the starting location of the
interrupt exception handler. The interrupt-acknowledge bus cycle is a read transfer that
differs from normal read cycles in the following respects:
•
•
•
•
•
TT[1:0] = 0x3 to indicate a CPU space or acknowledge bus cycle.
TM[2:0] = the level of interrupt being acknowledged.
A[31:5] = 0x7F_FFFF.
A[4:2] = the interrupt request level being acknowledged (same as TM[2:0]).
A[1:0] = 00.
During the interrupt-acknowledge bus cycle (a read cycle), the responding device places the
vector number on D[31:24] and the cycle is terminated normally with TA. Figure 18-23 is
a flow diagram for an interrupt-acknowledge cycle terminated with TA.
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18-19
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Bus Arbitration
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MCF5307
SYSTEM
1.
Drive 0x7FFFFF on A[31:5]
2.
Drive 0x0 on A[1:0]
3.
Drive interrupt level on A[4:2]
4.
Drive R/W to read (R/W = 1)
5.
Drive SIZ[1:0] to indicate byte (SIZ[1:0] = 01)
6.
Drive TT[1:0] and TM[2:0] to indicate interrupt
acknowledge (TT[1:0] = 11; TM[2:0] = interrupt
level)
7.
Assert TS for one BCLKO cycle
1.
Negate TS
2.
Drive TM[2:0] to indicate interrupt
acknowledge (TM[2:0] = interrupt level)
1.
Decode address and select the appropriate slave
device.
1.
Read and store data (D[31:24])
2.
Drive data on D[31:24]
2.
Recognize the transfer is done
3.
Assert TA for one BCLKO cycle
Figure 18-23. Interrupt-Acknowledge Cycle Flowchart
18.8 Bus Arbitration
The MCF5307 bus protocol gives either the MCF5307 or an external device access to the
external bus. If more than one external device uses the bus, an external arbiter can prioritize
requests and determine which device is bus master. When the MCF5307 is bus master, it
uses the bus to fetch instructions and transfer data to and from external memory. When an
external device is bus master, the MCF5307 can monitor the external master’s transfers and
interact through its chip-select, DRAM control, and transfer termination signals. See
Section 10.4.1.3, “Chip-Select Control Registers (CSCR0–CSCR7),” and Chapter 11,
“Synchronous/Asynchronous DRAM Controller Module.”
Two-wire bus arbitration is used where the MCF5307 shares the bus with a single external
device. This mode uses BG and BD. The external device can ignore BR. Three-wire mode
is used where the MCF5307 shares the bus with multiple external devices. This requires an
external bus arbiter and uses BG, BD, and BR. In either mode, the MCF5307 bus arbiter
operates synchronously and transitions between states on the rising edge of BCLKO.
Table 18-6 shows the four arbitration states the MCF5307 can be in during bus operation.
Table 18-6. MCF5307 Arbitration Protocol States
State
Master
Bus
BD
Reset
None
Not
driven
Negated
The MCF5307 enters reset state from any other state when RSTI or
software watchdog reset is asserted. If both are negated, the MCF5307
enters implicit or external device mastership state, depending on BG.
Implicit
master
MCF5307
Not
driven
Negated
The MCF5307 is bus master (BG input is asserted) but is not ready to
begin a bus cycle. It continues to three-state the bus until an internal bus
request.
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General Operation of External Master Transfers
Table 18-6. MCF5307 Arbitration Protocol States (Continued)
State
Master
Bus
Explicit
master
MCF5307
External
master
External
BD
Description
Driven Asserted The MCF5307 is explicit bus master when BG is asserted and at least
one bus cycle has been initiated. It asserts BD and retains explicit
mastership until BG is negated even if no active bus cycles are executed.
It releases the bus at the end of the current bus cycle, then negates BD
and three-states the bus signals.
Not
driven
Negated
An external device is bus master (BG negated to MCF5307). The
MCF5307 can assert OE, CS[7:0], BE/BWE[3:0], TA, and all DRAM
controller signals (RAS[1:0], CAS[3:0], SRAS, SCAS, DRAMW, SCKE).
Freescale Semiconductor, Inc...
If the MCF5307 is the only possible master, BG can be tied to GND—no arbiter is needed.
18.8.1 Bus Arbitration Signals
Bus arbitration signal timings in Table 18-7 are referenced to the system clock, which is not
considered a bus signal. Clock routing is expected to meet application requirements.
Table 18-7. ColdFire Bus Arbitration Signal Summary
Signal
I/O
Description
BR
O
Bus request. Indicates to an external arbiter that the processor needs to become bus master. BR is
negated when the MCF5307 begins an access to the external bus with no other internal accesses
pending. BR remains negated until another internal request occurs.
BG
I
Bus grant. An external arbiter asserts BG to indicate that the MCF5307 can control the bus at the
next rising edge of BCLKO. When the arbiter negates BG, the MCF5307 must release the bus as
soon as the current transfer completes. The external arbiter must not grant the bus to any other
device until both BD and BG are negated.
BD
O
Bus driven. The MCF5307 asserts BD to indicate it is current master and is driving the bus. If it loses
bus mastership during a transfer, it completes the last transfer of the current access, negates BD,
and three-states all bus signals on the rising edge of BCLKO. If it loses mastership during an idle
clock cycle, it three-states all bus signals on the rising edge of BCLKO.
18.9 General Operation of External Master Transfers
An external master asserts its hold signal (such as HOLDREQ) when it executes a bus
cycle, driving BG high and forcing the MCF5307 to hold all bus requests. During an
external master cycle, the MCF5307 can provide memory control signals (OE, CS[7:0],
BE/BWE[3:0], RAS[1:0], CAS[3:0]) and TA while the external master drives the address
and data bus and other required bus control signals. When the external master asserts TS or
AS to the MCF5307, the beginning of a bus cycle is identified and the MCF5307 starts
decoding the address driven.
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General Operation of External Master Transfers
Note the following regarding external master accesses:
For the MCF5307 to assert a CSx during external master accesses, CSMRn[AM]
must be set. External master hits use the corresponding CSCRn settings for
auto-acknowledge, byte enables, and wait states. See Section 10.4.1.3, “Chip-Select
Control Registers (CSCR0–CSCR7).”
To enable DRAM control signals during external master accesses, DCMRn[AM]
must be set.
During external master bus cycles, either TS or AS (but not both) should be driven
to the MCF5307. Driving both during a bus cycle causes indeterminate results.
•
•
Freescale Semiconductor, Inc...
•
External master transfers that use the MCF5307 to drive memory control signals and TA
are like normal MCF5307 transfers. Figure 18-24 shows timing for basic back-to-back bus
cycles during an external master transfer.
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
BCLKO
A[31:0], TT[1:0]
SIZ[1:0], TM[2:0]
R/W
TIP
TS
AS
CS 1
BE/BWE 1
D[31:0]
TA 1
BR 2
BG, BD 2
HOLDREQ
External Master
1 Depending on programming, these signals may or may not be driven
2 This signal is driven by the processor for an external master transfer.
by the processor.
Figure 18-24. Basic No-Wait-State External Master Access
R/W is asserted high for reads and low for writes; otherwise, the transfers are the same. In
Figure 18-24, the MCF5307 chip select’s internal transfer acknowledge is enabled and the
MCF5307 drives TA as an output after a programmed number of wait states.
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General Operation of External Master Transfers
NOTE:
Bus timing diagrams for external master transfers are not valid
for on-chip internal four-channel DMA accesses on the
MCF5307.
Timing diagrams describe transactions in general terms of bus
cycles (Cn) rather than the states (Sn) used in the bus diagrams.
Table 18-8 defines the cycles for Figure 18-24.
Table 18-8. Cycles for Basic No-Wait-State External Master Access
Freescale Semiconductor, Inc...
Cycle
C1
Definition
The external master asserts HOLDREQ, signaling the MCF5307 to hold bus requests. BD should not be
asserted. The external master drives address, TS, R/W, TT[1:0], TM[2:0], TIP, and SIZ[1:0] as MCF5307
inputs.
C2–C3 The MCF5307 decodes the external master’s address and control signals to identify the proper chip select
and byte enable assertion. The external master negates TS in C2.
C4
On the falling edge of BCLKO, the MCF5307 asserts the appropriate chip select for the external master
access along with the appropriate byte enables.
C5
On the rising edge of BCLKO, data is driven onto the bus by the device selected by CS. On the rising edge,
the MCF5307 asserts TA to indicate the cycle is complete.
C6
TA negates on the rising edge of BCLKO. On the falling edge, the MCF5307 negates the chip select and
byte enables and the next cycle can begin.
C7
The external master negates TIP on the rising edge of BCLKO.
C8
The external device retains bus mastership and drives the address bus, TS, R/W, TT[1:0], TM[2:0], TIP, and
SIZ[1:0] as inputs to the MCF5307.
C9
The MCF5307 decodes the external master’s address and control signals to identify the proper chip select
and byte enable assertion. The external master negates TS. The MCF5307 asserts BR on the rising edge of
BCLKO, signalling that it wants to arbitrate for the bus when the current cycle completes.
C10
The MCF5307 continues to decode the external device’s address and control signals to identify the proper
chip select and byte enable assertion.
C11
On the falling edge of BCLKO, the MCF5307 asserts the appropriate chip select for the external master
access along with the appropriate byte enables.
Figure 18-25 shows a burst line access for an external master transfer with the chip select
set to no-wait states and with internal transfer-acknowledge assertion enabled.
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General Operation of External Master Transfers
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
BCLKO
A[31:0]
R/W
TT[1:0], TM[2:0]
SIZ[1:0]
TIP
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TS
AS, BR 2
CS 1
BE/BWE 1
D[31:0]
TA 1
BG, BD 2
HOLDREQ
External Master
1 Depending on programming, these signals may or may not be driven by the
2 These signals are driven by the processor for an external master transfer.
processor.
Figure 18-25. External Master Burst Line Access to 32-Bit Port
Table 18-9 defines the cycles for Figure 18-25.
Table 18-9. Cycles for External Master Burst Line Access to 32-Bit Port
Cycle
Definition
C1
The external device is bus master and asserts HOLDREQ, indicating to the MCF5307 to hold all bus
requests. In other words, BD should not be asserted. The external master drives address, TS, R/W, TT[1:0],
TM[2:0], TIP, and SIZ[1:0] as inputs to the MCF5307. SIZ[1:0] inputs indicate a line transfer. The MCF5307
is not asserting BR.
C2–C3
The MCF5307 decodes the external device’s address and control signals to identify the proper chip-select
and byte-enable assertion. The external device negates TS in C2. Address and R/W are latched in the
MCF5307 on the rising edge of BCLKO in C2. After C2, the address and R/W are ignored for the rest of the
burst transfer.
C4
On the falling edge of BCLKO, the MCF5307 asserts the appropriate chip select for the external device
access along with the appropriate byte enables.
C5
On the rising edge of BCLKO, data is driven onto the bus by the device selected by CS. The MCF5307
asserts TA on the rising edge of BCLKO, indicating the first data transfer is complete.
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General Operation of External Master Transfers
Table 18-9. Cycles for External Master Burst Line Access to 32-Bit Port (Continued)
Cycle
C6–C8
C9
Definition
No-wait state data transfers 2–4 occur on the rising edges of BCLKO. TA continues to be asserted
indicating completion of each transfer. TIP, CSx, and BE/BWE[3:0] are driven.
TA negates on the rising edge of BCLKO along with external device’s negation of TIP. On the falling edge,
the MCF5307 negates chip select and byte enables, creating an opportunity for another cycle to begin.
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18.9.1 Two-Device Bus Arbitration Protocol (Two-Wire
Mode)
Two-wire mode bus arbitration lets the MCF5307 share the external bus with a single
external bus device without requiring an external bus arbiter. Figure 18-26 shows the
MCF5307 connecting to an external device using the two-wire mode. The MCF5307 BG
input is connected to the HOLDREQ output of the external device; the MCF5307 BD
output is connected to the HOLDACK input of the external device. Because the external
device controls the state of HOLDREQ, it controls when the MCF5307 is granted the bus,
giving the MCF5307 lower priority.
BG
HOLDREQ
HOLDACK
BD
BR
A[31:0]
A[31:0]
D[31:0]
TS
R/W
SIZ[1:0]
TA
D[31:0]
TS
R/W
SIZ[1:0]
TA
External Bus Master
MCF5307
To/from external memory and control
Figure 18-26. MCF5307 Two-Wire Mode Bus Arbitration Interface
When the external device is not using the bus, it negates HOLDREQ, driving BG low and
granting the bus to the MCF5307. When the MCF5307 has an internal bus request pending
and BG is low, the MCF5307 drives BD low, negating HOLDACK to the external device.
When the external bus device needs the external bus, it asserts HOLDREQ, driving BG
high, requesting the MCF5307 to release the bus. If BG is negated while a bus cycle is in
progress, the MCF5307 releases the bus at the completion of the bus cycle. Note that the
MCF5307 considers the individual transfers of a burst or burst-inhibited access to be a
single bus cycle and does not release the bus until the last transfer of the series completes.
When the bus has been granted to the MCF5307, one of two situations can occur. In the first
case, if the MCF5307 has an internal bus request pending, the MCF5307 asserts BD to
indicate explicit bus mastership and begins the pending bus cycle by asserting TS. As
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General Operation of External Master Transfers
shown in Figure 18-25, the MCF5307 continues to assert BD until the completion of the
bus cycle. If BG is negated by the end of the bus cycle, the MCF5307 negates BD. While
BG is asserted, BD remains asserted to indicate the MCF5307 is master, and it continuously
drives the address bus, attributes, and control signals.
s
C1
C2
C3
C4
C5
C6
C7
C8
C9
BCLKO
A[31:0], TT[1:0]
SIZ[1:0], TM[2:0]
R/W
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TIP
TS
AS
D[31:0]
TA
BG
BD
External Master
MCF5307
Figure 18-27. Two-Wire Bus Arbitration with Bus Request Asserted
In the second situation, the bus is granted to the MCF5307, but it does not have an internal
bus request pending, so it takes implicit bus mastership. The MCF5307 does not drive the
bus and does not assert BD if the bus has an implicit master. If an internal bus request is
generated, the MCF5307 assumes explicit bus mastership. If explicit mastership was
assumed because an internal request was generated, the MCF5307 immediately begins an
access and asserts BD.
In Figure 18-28, the external device is bus master during C1 and C2. During C3 the external
device releases control of the bus by asserting BG to the MCF5307. At this point, there is
an internal access pending so the MCF5307 asserts BD during C4 and begins the access.
Thus, the MCF5307 becomes the explicit external bus master. Also during C4, the external
device removes the grant from the MCF5307 by negating BG. As the current bus master,
the MCF5307 continues to assert BD until the current transfer completes. Because BG is
negated, the MCF5307 negates BD during C9 and three-states the external bus, thereby
returning external bus mastership to the external device.
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General Operation of External Master Transfers
C1
C2
C3
C4
C5
C6
C7
C8
C9
BCLKO
A[31:0], TT[1:0]
SIZ[1:0], TM[2:0]
R/W
TIP
TS
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AS
D[31:0]
TA
BG
BD
Implicit
Mastership
External Master
Explicit
Mastership
MCF5307
Figure 18-28. Two-Wire Implicit and Explicit Bus Mastership
In Figure 18-28, the external device is master during C1 and C2. It releases bus control in
C3 by asserting BG to the MCF5307. During C4 and C5, the MCF5307 is implicit master
because no internal access is pending. In C5, an internal bus request becomes pending,
causing the MCF5307 to become explicit bus master in C6 by asserting BD. In C7, the
external device removes the bus grant to the MCF5307. The MCF5307 does not release the
bus (the MCF5307 continues to assert BD) until the transfer ends.
NOTE:
The MCF5307 can start a transfer in the clock cycle after BG
is asserted. The external master must not assert BG to the
MCF5307 while driving the bus or the part may be damaged.
Chapter 5, “Debug Support is a MCF5307 bus arbitration state diagram. States are
described in Table 18-6.
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General Operation of External Master Transfers
A1
A2
Reset
A4
A3
B1
External
Master
D1
Implicit
Master
D3
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D2
D4
B3
B2
B4
C3
C5
Explicit
Master
C1
C2
C4
Figure 18-29. MCF5307 Two-Wire Bus Arbitration Protocol State Diagram
Table 18-10 describes the two-wire bus arbitration protocol transition conditions.
Table 18-10. MCF5307 Two-Wire Bus Arbitration Protocol Transition Conditions
Present
State
Condition
Label
RSTI
Software Watchdog
Reset
BG
Bus
Request
Transfer in
Progress
End of
Cycle1
Next
State
A1
A2
—
—
—
—
—
Reset
A2
N3
A
—
—
—
—
Reset
A3
N
N
N
—
—
—
EM 4
Implicit mas
Reset
Implicit
Master
Explicit
Master
External
Master
18-28
A4
N
N
A
—
—
—
B1
N
N
N
—
—
—
EM
B2
N
N
A
—
—
—
Explicit mas
B3
N
N
A
N
—
—
Implicit mas
B4
N
N
A
A
—
—
Explicit mas
C1
N
N
A
—
—
—
Explicit mas
C2
N
N
N
—
—
—
Explicit mas
C3
N
N
N
—
N
—
EM
C4
N
N
N
—
A
N
Explicit mas
C5
N
N
N
—
A
A
EM
D1
N
N
N
—
—
—
EM mas
D2
N
N
A
—
—
—
Explicit mas
D3
N
N
A
N
—
—
Implicit mas
D4
N
N
A
A
—
—
Explicit mas
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General Operation of External Master Transfers
1
Both normal terminations and terminations due to bus errors generate an end of cycle. Bus cycles resulting from
a burst-inhibited transfer are considered part of that original transfer.
2 A means asserted.
3 N means negated.
4 EM means external master.
Freescale Semiconductor, Inc...
18.9.2 Multiple External Bus Device Arbitration Protocol
(Three-Wire Mode)
Three-wire mode lets the MCF5307 share the external bus with multiple external devices.
This mode requires an external arbiter to assign priorities to each potential master and to
determine which device accesses the external bus. The arbiter uses the MCF5307 bus
arbitration signals, BR, BD, and BG, to control use of the external bus by the MCF5307.
The MCF5307 requests the bus from the external bus arbiter by asserting BR when the core
requests an access. It continues to assert BR until after the transfer starts. It can negate BR
at any time regardless of the BG status. If the MCF5307 is granted the bus when an internal
bus request is generated, it asserts BD and the access begins immediately. The MCF5307
always drives BR and BD, which cannot be directly wire-ORed with other devices.
The external arbiter asserts BG to grant the bus to MCF5307, which can begin a bus cycle
after the next rising edge of BCLKO. If BG is negated during a bus cycle, the MCF5307
releases the bus when the cycle completes. To guarantee that the bus is released, BG must
be negated before the rising edge of the BCLKO in which the last TA is asserted. Note that
the MCF5307 treats any series of burst or a burst-inhibited transfers as a single bus cycle
and does not release the bus until the last transfer of the series completes.
When the MCF5307 is granted the bus after it asserts BR, one of two things can occur. If
the MCF5307 has an internal bus request pending, it asserts BD, indicating explicit bus
mastership, and begins the pending bus cycle by asserting TS. The MCF5307 continues to
assert BD until the external bus arbiter negates BG, after which BD is negated at the
completion of the bus cycle. As long as BG is asserted, BD remains asserted to indicate that
the MCF5307 is bus master, and the MCF5307 continuously drives the address bus,
attributes, and control signals.
If no internal request is pending, the MCF5307 takes implicit bus mastership. It does not
drive the bus and does not assert BD if the bus has an implicit master. If an internal bus
request is generated, the MCF5307 assumes explicit bus mastership and immediately
begins an access and asserts BD. Figure 18-30 shows implicit and explicit bus mastership
due to generation of an internal bus request.
Chapter 18. Bus Operation
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18-29
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General Operation of External Master Transfers
C1
C2
C3
C4
C5
C6
C7
C8
C9
BCLKO
A[31:0], TT[1:0]
SIZ[1:0], TM[2:0]
R/W
TIP
TS
Freescale Semiconductor, Inc...
AS
D[31:0]
TA
BR
BG
BD
Implicit
Mastership
External Master
Explicit
Mastership
MCF5307
Figure 18-30. Three-Wire Implicit and Explicit Bus Mastership
In Figure 18-30, the external device is bus master during C1 and C2, releasing control in
C3, at which time the external arbiter asserts BG to the MCF5307. During C4 and C5, the
MCF5307 is implicit master because no internal access is pending. In C5, an internal bus
request becomes pending, causing the MCF5307 to take explicit bus mastership in C6 by
asserting BR and BD. In C7, the external device removes the bus grant to the MCF5307.
The MCF5307 does not release the bus (the MCF5307 asserts BD) until the transfer ends.
NOTE:
The MCF5307 can start a transfer in the cycle after BG is
asserted. The external arbiter should not assert BG to the
MCF5307 until the previous external master stops driving the
bus. Asserting BG during another external master’s transfer
may damage the part.
18-30
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General Operation of External Master Transfers
C1
C2
C3
C4
C5
C6
C7
C8
C9
BCLKO
A[31:0], TT[1:0]
SIZ[1:0], TM[2:0]
R/W
TIP
TS
Freescale Semiconductor, Inc...
AS
D[31:0]
TA
BR
BG
BD
External
Master
MCF5307
Figure 18-31. Three-Wire Bus Arbitration
In Figure 18-31, the external device is bus master during C1 and C2. During C2, the
MCF5307 requests the external bus because of a pending internal transfer. On C3, the
external releases mastership and the external arbiter grants the bus to the MCF5307 by
asserting BG. At this point, an internal is access pending so the MCF5307 asserts BD
during C4 and begins the access. Thus, the MCF5307 becomes the explicit bus master. Also
during C4, the external arbiter removes the grant from the MCF5307 by negating BG.
Because the MCF5307 is bus master, it continues to assert BD until the current transfer
completes. Because BG is negated, the MCF5307 negates BD during C9 and three-states
the external bus, thereby passing mastership to an external device.
The MCF5307 can assert BR to signal the external arbiter that it needs the bus. However,
there is no guarantee that when the bus is granted to the MCF5307 that a bus cycle will be
performed. At best, BR must be used as a status output that indicates when the MCF5307
needs the bus, but not as an indication that the MCF5307 is in a certain bus arbitration state.
Figure 18-32 is a high-level state diagram for MCF5307 bus arbitration protocol.
Table 18-6 describes the four states shown in Figure 18-32.
Chapter 18. Bus Operation
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18-31
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General Operation of External Master Transfers
A1
A2
Reset
A4
A3
D1
B1
External
Master
Implicit
Master
D3
Freescale Semiconductor, Inc...
D2
D4
B3
B2
B4
C3
C5
Explicit
Master
C1
C2
C4
Figure 18-32. Three-Wire Bus Arbitration Protocol State Diagram
Table 18-11 lists conditions that cause state transitions.
Table 18-11. Three-Wire Bus Arbitration Protocol Transition Conditions
Current
State
Reset
Implicit
master
18-32
Software
Watchdog
Reset
BG
Bus
Request
Transfer
in
Progress
End of
Cycle 1
Next State
Asserted
—
—
—
—
—
Reset
Negated
Asserted
—
—
—
—
Reset
Condition
Label
RSTI
A1
A2
A3
Negated
Negated
Negated
—
—
—
EM
A4
Negated
Negated
Asserted
—
—
—
Implicit
master
B1
Negated
Negated
Negated
—
—
—
External
device
master
B2
Negated
Negated
Asserted
—
—
—
Explicit
master
B3
Negated
Negated
Asserted
Negated
—
—
Implicit
master
B4
Negated
Negated
Asserted
Asserted
—
—
Explicit
master
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Reset Operation
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Table 18-11. Three-Wire Bus Arbitration Protocol Transition Conditions (Continued)
Current
State
Condition
Label
RSTI
Software
Watchdog
Reset
BG
Bus
Request
Transfer
in
Progress
End of
Cycle 1
Explicit
master
C1
Negated
Negated
Asserted
—
—
—
Explicit
master
C2
Negated
Negated
Negated
—
—
—
Explicit
master
C3
Negated
Negated
Negated
—
Negated
—
External
device
master
C4
Negated
Negated
Negated
—
Yes
Negated
Explicit
master
C5
Negated
Negated
Negated
—
Yes
Yes
External
device
master
D1
Negated
Negated
Negated1
—
—
—
External
device
master
D2
Negated
Negated
Asserted
—
—
—
Explicit
master
D3
Negated
Negated
Asserted
Negated
—
—
Implicit
master
D4
Negated
Negated
Asserted
Asserted
—
—
Explicit
master
External
master
1
Next State
Both normal terminations and terminations due to bus errors generate an end of cycle. Bus cycles resulting from
a burst-inhibited transfer are considered part of that original transfer.
The bus arbitration state diagram can be used for the MCF5307 three-wire bus arbitration
protocol to approximate the high-level behavior of the MCF5307. It is assumed that all TS
or AS signals in a system are tied together and each bus device’s BD and BR signals are
connected individually to the external arbiter. The external arbiter must ensure that any
external masters will have released the bus after the next rising edge of before asserting BG
to the MCF5307. The MCF5307 does not monitor external bus master operation regarding
bus arbitration.
NOTE:
The MCF5307 can start a transfer on the rising edge of the
cycle after BG is asserted. The external arbiter should not assert
BG to the MCF5307 until the previous external master stops
driving the bus or the part may be damaged.
18.10 Reset Operation
The MCF5307 supports two types of reset. Asserting RSTI resets the entire MCF5307. A
software watchdog reset resets everything but the internal PLL module.
Chapter 18. Bus Operation
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18-33
Reset Operation
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18.10.1 Master Reset
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To perform a master reset, an external device asserts RSTI. When power is applied to the
system, external circuitry should assert RSTI for a minimum of 80 CLKIN cycles after Vcc
is within tolerance. Figure 18-33 is a functional timing diagram of the master reset
operation, showing relationships among Vcc, RSTI, mode selects, and bus signals. CLKIN
must be stable by the time Vcc reaches the minimum operating specification. CLKIN
should start oscillating as Vcc is ramped up to clear out contention internal to the MCF5307
caused by the random states of internal flip-flops on power up. RSTI is internally
synchronized for two CLKIN cycles before being used and must meet the specified setup
and hold times in relationship to CLKIN to be recognized.
>80 CLKIN cycles
100K CLKIN cycles
PLL lock time
CLKIN
VCC
RSTI
RSTO
D[7:0]
Bus Signals
BR
BD
Figure 18-33. Master Reset Timing
During the master reset period, all signals capable of being three-stated are driven to a
high-impedance; all others are negated. When RSTI negates, all bus signals remain in a
high-impedance state until the MCF5307 is granted the bus and the core begins the first bus
cycle for reset exception processing. A master reset causes any bus cycle (including DRAM
refresh cycle) to terminate and initializes registers appropriately for a reset exception.
Note that during reset D[7:0] are sampled on the negating edge of RSTI for initial
MCF5307 configurations listed in Table 18-12.
18-34
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Reset Operation
Table 18-12. Data Pin Configuration
Pin
D7
D[6:5]
D4
Function
Auto-Acknowledge Configuration (AA_CONFIG)
Port Size Configuration (PS_CONFIG[1:0])
Address Configuration (ADDR_CONFIG/D4)
D[3:2]
Frequency of CLKIN (FREQ[1:0])
D[1:0]
Ratio of BCLKO/Processor Clock {DIVIDE[1:0])
Freescale Semiconductor, Inc...
See Section 17.5.5, “Data/Configuration Pins (D[7:0]).” Motorola recommends that the
data pins be driven rather than using a weak pull-up or pull-down resistor. Table 17-1 lists
the encoding of these pins sampled at reset.
18.10.2 Software Watchdog Reset
A software watchdog reset is performed if the executing software does not provide the
correct write data sequence with the enable-control bit set. This reset helps prevent runaway
software or unterminated bus cycles. Figure 18-34 is a functional timing diagram of the
software watchdog reset operation, showing RSTO and bus signal relationships.
Chapter 18. Bus Operation
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18-35
Reset Operation
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>80 CLKIN
100K CLKIN
Cycle Lock Time
CLKIN
30 BCLKO
BCLKO
(1/2 MODE)
20 BCLKO
BCLKO
(1/3 MODE)
Freescale Semiconductor, Inc...
15 BCLKO
BCLKO
(1/4 MODE)
PSTCLK
RSTI
D[7:0]
D[7:0] latched
RSTO
Figure 18-34. Software Watchdog Reset Timing
During the software watchdog reset period, all signals that can be are driven to a
high-impedance state; all those that cannot be are negated. When RSTO negates, bus
signals remain in a high-impedance state until the MCF5307 is granted the bus and the
ColdFire core begins the first bus cycle for reset exception processing.
18-36
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Chapter 19
IEEE 1149.1 Test Access Port (JTAG)
This chapter describes configuration and operation of the MCF5307 JTAG test
implementation. It describes the use of JTAG instructions and provides information on how
to disable JTAG functionality.
19.1 Overview
The MCF5307 dedicated user-accessible test logic is fully compliant with the publication
Standard Test Access Port and Boundary-Scan Architecture, IEEE Standard 1149.1. Use the
following description in conjunction with the supporting IEEE document listed above. This
section includes the description of those chip-specific items that the IEEE standard requires
as well as those items specific to the MCF5307 implementation.
The MCF5307 JTAG test architecture supports circuit board test strategies based on the
IEEE standard. This architecture provides access to all data and chip control pins from the
board-edge connector through the standard four-pin test access port (TAP) and the JTAG
reset pin, TRST. Test logic design is static and is independent of the system logic except
where the JTAG is subordinate to other complimentary test modes, as described in
Chapter 5, “Debug Support.” When in subordinate mode, JTAG test logic is placed in reset
and the TAP pins can be used for other purposes, as described in Table 19-1.
The MCF5307 JTAG implementation can do the following:
•
•
•
•
•
Perform boundary-scan operations to test circuit board electrical continuity
Bypass the MCF5307 by reducing the shift register path to a single cell
Set MCF5307 output drive pins to fixed logic values while reducing the shift register
path to a single cell
Sample MCF5307 system pins during operation and transparently shift out the result
Protect MCF5307 system output and input pins from backdriving and random
toggling (such as during in-circuit testing) by placing all system pins in highimpedance state
NOTE:
IEEE Standard 1149.1 may interfere with system designs that do
not incorporate JTAG capability. Section 19.6, “Disabling IEEE
Standard 1149.1 Operation,” describes precautions for ensuring
that this logic does not affect system or debug operation.
Chapter 19. IEEE 1149.1 Test Access Port (JTAG)
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19-1
JTAG Signal Descriptions
Freescale Semiconductor, Inc.
Figure 19-1 is a block diagram of the MCF5307 implementation of the 1149.1 IEEE
standard. The test logic includes several test data registers, an instruction register,
instruction register control decode, and a 16-state dedicated TAP controller.
Test Data Registers
V+
TDI
Boundary Scan Register
M
U
X
ID Code
Freescale Semiconductor, Inc...
Bypass
3-Bit Instruction Decode
3-Bit Instruction Register
M
U
X
TDO
V+
TMS
TCK
TAP
V+
TRST
Figure 19-1. JTAG Test Logic Block Diagram
19.2 JTAG Signal Descriptions
JTAG operation on the MCF5307 is enabled when MTMOD0 is high (logic 1), as described
in Table 19-1. Otherwise, JTAG TAP signals, TCK, TMS, TDI, TDO, and TRST, are
interpreted as the debug port pins. MTMOD0 should not be changed while RSTI is
asserted.
Table 19-1. JTAG Pin Descriptions
Pin
Description
TCK
Test clock. The dedicated JTAG test logic clock is independent of the MCF5307 processor clock. Various
JTAG operations occur on the rising or falling edge of TCK. Internal JTAG controller logic is designed such
that holding TCK high or low indefinitely does cause the JTAG test logic to lose state information. If TCK is
not used, it should be tied to ground.
TMS/
BKPT
Test mode select (MTMOD0 high)/breakpoint (MTMOD0 low). TMS provides the JTAG controller with
information to determine the test operation mode. The states of TMS and of the internal 16-state JTAG
controller state machine at the rising edge of TCK determine whether the JTAG controller holds its current
state or advances to the next state. This directly controls whether JTAG data or instruction operations
occur. TMS has an internal pull-up, so if it is not driven low, its value defaults to a logic level of 1. If TMS is
not used, it should be tied to VDD. BKPT signals a hardware breakpoint to the processor in debug mode.
See Chapter 5, “Debug Support.”
19-2
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TAP Controller
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Table 19-1. JTAG Pin Descriptions
Pin
Description
TDI/DSI
Test data input (MTMOD0 high)/development serial input (MTMOD0 low). TDI provides the serial data port
for loading the JTAG boundary-scan, bypass, and instruction registers. Shifting in of data depends on the
state of the JTAG controller state machine and the instruction in the instruction register. This shift occurs on
the rising edge of TCK. TDI has an internal pull-up so if it is not driven low its value defaults to a logical 1. If
TDI is not used, it should be tied to VDD.
DSI provides single-bit communication for debug module commands. See Chapter 5, “Debug Support.”
TDO/
DSO
Test data output (MTMOD0 high)/development serial output (MTMOD0 low). TDO is the serial data port for
outputting data from JTAG logic. Shifting data out depends on the state of the JTAG controller state
machine and the instruction currently in the instruction register. This shift occurs on the falling edge of TCK.
When not outputting test data, TDO is three-stated. It can also be placed in three-state mode to allow
bussed or parallel connections to other devices having JTAG. DSO provides single-bit communication for
debug module commands. See Chapter 5, “Debug Support.”
TRST/ Test reset (MTMOD0 high)/development serial clock (MTMOD0 low). As TRST, this pin asynchronously
DSCLK resets the internal JTAG controller to the test logic reset state, causing the JTAG instruction register to
choose the IDCODE instruction. When this occurs, all JTAG logic is benign and does not interfere with
normal MCF5307 functionality. Although this signal is asynchronous, Motorola recommends that TRST
make only an asserted-to-negated transition while TMS is held at a logic 1 value. TRST has an internal
pull-up; if it is not driven low its value defaults to a logic level of 1. However, if TRST is not used, it can
either be tied to ground or, if TCK is clocked, to VDD. The former connection places the JTAG controller in
the test logic reset state immediately; the latter connection eventually puts the JTAG controller (if TMS is a
logic 1) into the test logic reset state after 5 TCK cycles.
DSCLK is the development serial clock for the serial interface to the debug module.The maximum DSCLK
frequency is 1/2 the BCLKO frequency. See Chapter 5, “Debug Support.”
19.3 TAP Controller
The state of TMS at the rising edge of TCK determines the current state of the TAP
controller. The TAP controller can follow two basic two paths, one for executing JTAG
instructions and the other for manipulating JTAG data based on JTAG instructions. The
various states of the TAP controller are shown in Figure 19-2. For more detail on each state,
see the IEEE Standard 1149.1 JTAG document. Note that regardless of the TAP controller
state, test-logic-reset can be entered if TMS is held high for at least five rising edges of
TCK. Figure 19-2 shows the JTAG TAP controller state machine.
Chapter 19. IEEE 1149.1 Test Access Port (JTAG)
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19-3
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JTAG Register Descriptions
1
Test-Logic-Reset
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