C8051F360/1/2/3/4/5/6/7/8/9
Mixed Signal ISP Flash MCU Family
Analog Peripherals
- 10-Bit ADC (‘F360/1/2/6/7/8/9 only)
• Up to 200 ksps
• Up to 21 external single-ended or differential inputs
• VREF from internal VREF, external pin or VDD
• Internal or external start of conversion source
• Built-in temperature sensor
- 10-Bit Current Output DAC
Memory
- 1280 bytes internal data RAM (256 + 1024)
- 32 kB (‘F360/1/2/3/4/5/6/7) or 16 kB (‘F368/9) Flash;
-
-
Programmable hysteresis and response time
Configurable as interrupt or reset source
Low current (0.4 µA)
- Brown-out detector and POR Circuitry
On-Chip Debug
- On-chip debug circuitry facilitates full speed, non-
intrusive in-system debug (no emulator required)
Provides breakpoints, single stepping,
inspect/modify memory and registers
Superior performance to emulation systems using
ICE-chips, target pods, and sockets
Low cost, complete development kit
Supply Voltage
- Range: 2.7–3.6 V (50 MIPS) 3.0–3.6 V (100 MIPS)
- Power saving suspend and shutdown modes
High Speed 8051 µC Core
- Pipelined instruction architecture; executes 70% of
-
instructions in 1 or 2 system clocks
100 MIPS or 50 MIPS throughput with on-chip PLL
Expanded interrupt handler
2-cycle 16 x 16 MAC engine
ANALOG
PERIPHERALS
+
VOLTAGE
COMPARATORS
-
A
M
U
X
10-bit
200 ksps
ADC
+
-
TEMP
SENSOR
10-bit
Current
DAC
‘F360/1/2/6/7/8/9 only
-
rent
Hardware enhanced UART, SMBus™, and
enhanced SPI™ serial ports
Four general purpose 16-bit counter/timers
16-Bit programmable counter array (PCA) with six
capture/compare modules
Real time clock mode using PCA or timer and external clock source
External Memory Interface (EMIF)
Clock Sources
- Two internal oscillators:
• 24.5 MHz with ±2% accuracy supports crystal-less
-
•
UART operation
80/40/20/10 kHz low frequency, low power
Flexible PLL technology
External oscillator: Crystal, RC, C, or clock
(1 or 2 pin modes)
Can switch between clock sources on-the-fly; useful
in power saving modes
Packages
- 48-pin TQFP (C8051F360/3)
- 32-pin LQFP (C8051F361/4/6/8)
- 28-pin QFN (C8051F362/5/7/9)
Temperature Range: –40 to +85 °C
DIGITAL I/O
UART
SMBus
SPI
PCA
Timer 0
Timer 1
Timer 2
Timer 3
External Memory Interface
•
•
•
Digital Peripherals
- Up to 39 Port I/O; All 5 V tolerant with high sink cur-
CROSSBAR
(‘F360/1/2/6/7/8/9 only)
Two Comparators
In-system programmable in 1024-byte Sectors—
1024 bytes are reserved in the 32 kB devices
Port 0
Port 1
Port 2
Port 3
Port 3
Port 4
48-pin only
HIGH-SPEED CONTROLLER CORE
WDT
16 x 16
MAC
FLEXIBLE
INTERRUPTS
Rev. 1.2 10/22
8051 CPU
(100 or 50 MIPS)
DEBUG
CIRCUITRY
1024 B
SRAM
Internal Oscillator/
LFO/PLL
POR
32/16 kB
ISP FLASH
Copyright © 2022 by Silicon Laboratories
C8051F36x
C8051F360/1/2/3/4/5/6/7/8/9
2
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Table of Contents
1. System Overview.................................................................................................... 18
1.1. CIP-51™ Microcontroller Core.......................................................................... 23
1.1.1. Fully 8051 Compatible.............................................................................. 23
1.1.2. Improved Throughput ............................................................................... 23
1.1.3. Additional Features .................................................................................. 24
1.2. On-Chip Memory............................................................................................... 25
1.3. On-Chip Debug Circuitry................................................................................... 25
1.4. Programmable Digital I/O and Crossbar ........................................................... 26
1.5. Serial Ports ....................................................................................................... 27
1.6. Programmable Counter Array ........................................................................... 27
1.7. 10-Bit Analog to Digital Converter..................................................................... 28
1.8. Comparators ..................................................................................................... 29
1.9. 10-bit Current Output DAC................................................................................ 31
2. Absolute Maximum Ratings .................................................................................. 33
3. Global Electrical Characteristics .......................................................................... 34
4. Pinout and Package Definitions............................................................................ 37
5. 10-Bit ADC (ADC0, C8051F360/1/2/6/7/8/9)........................................................... 48
5.1. Analog Multiplexer ............................................................................................ 49
5.2. Temperature Sensor ......................................................................................... 50
5.3. Modes of Operation .......................................................................................... 52
5.3.1. Starting a Conversion............................................................................... 52
5.3.2. Tracking Modes........................................................................................ 53
5.3.3. Settling Time Requirements ..................................................................... 54
5.4. Programmable Window Detector ...................................................................... 59
5.4.1. Window Detector In Single-Ended Mode ................................................. 61
5.4.2. Window Detector In Differential Mode...................................................... 62
6. 10-Bit Current Mode DAC (IDA0, C8051F360/1/2/6/7/8/9) .................................... 64
6.1. IDA0 Output Scheduling ................................................................................... 64
6.1.1. Update Output On-Demand ..................................................................... 64
6.1.2. Update Output Based on Timer Overflow ................................................ 65
6.1.3. Update Output Based on CNVSTR Edge................................................. 65
6.2. IDAC Output Mapping....................................................................................... 65
7. Voltage Reference (C8051F360/1/2/6/7/8/9) .......................................................... 68
8. Comparators ........................................................................................................... 71
9. CIP-51 Microcontroller ........................................................................................... 81
9.1. Performance ..................................................................................................... 81
9.2. Programming and Debugging Support ............................................................. 82
9.3. Instruction Set ................................................................................................... 83
9.3.1. Instruction and CPU Timing ..................................................................... 83
9.3.2. MOVX Instruction and Program Memory ................................................. 83
9.4. Memory Organization........................................................................................ 87
9.4.1. Program Memory...................................................................................... 87
9.4.2. Data Memory............................................................................................ 88
Rev. 1.2
3
C8051F360/1/2/3/4/5/6/7/8/9
9.4.3. General Purpose Registers ...................................................................... 88
9.4.4. Bit Addressable Locations........................................................................ 88
9.4.5. Stack ....................................................................................................... 88
9.4.6. Special Function Registers....................................................................... 89
9.4.7. Register Descriptions ............................................................................. 103
9.5. Power Management Modes ............................................................................ 105
9.5.1. Idle Mode................................................................................................ 106
9.5.2. Stop Mode .............................................................................................. 106
9.5.3. Suspend Mode ....................................................................................... 106
10. Interrupt Handler .................................................................................................. 108
10.1.MCU Interrupt Sources and Vectors............................................................... 108
10.2.Interrupt Priorities ........................................................................................... 109
10.3.Interrupt Latency............................................................................................. 109
10.4.Interrupt Register Descriptions ....................................................................... 110
10.5.External Interrupts .......................................................................................... 116
11. Multiply And Accumulate (MAC0) ....................................................................... 118
11.1.Special Function Registers............................................................................. 118
11.2.Integer and Fractional Math............................................................................ 119
11.3.Operating in Multiply and Accumulate Mode .................................................. 120
11.4.Operating in Multiply Only Mode .................................................................... 120
11.5.Accumulator Shift Operations......................................................................... 120
11.6.Rounding and Saturation................................................................................ 121
11.7.Usage Examples ............................................................................................ 121
11.7.1.Multiply and Accumulate Example ......................................................... 121
11.7.2.Multiply Only Example............................................................................ 122
11.7.3.MAC0 Accumulator Shift Example ......................................................... 122
12. Reset Sources....................................................................................................... 129
12.1.Power-On Reset ............................................................................................. 130
12.2.Power-Fail Reset/VDD Monitor ...................................................................... 131
12.3.External Reset ................................................................................................ 132
12.4.Missing Clock Detector Reset ........................................................................ 132
12.5.Comparator0 Reset ........................................................................................ 132
12.6.PCA Watchdog Timer Reset .......................................................................... 133
12.7.Flash Error Reset ........................................................................................... 133
12.8.Software Reset ............................................................................................... 133
13. Flash Memory ....................................................................................................... 136
13.1.Programming the Flash Memory .................................................................... 136
13.1.1.Flash Lock and Key Functions ............................................................... 136
13.1.2.Erasing Flash Pages From Software ..................................................... 137
13.1.3.Writing Flash Memory From Software.................................................... 137
13.1.4.Non-volatile Data Storage ...................................................................... 138
13.2.Security Options ............................................................................................. 139
13.2.1.Summary of Flash Security Options....................................................... 140
13.3.Flash Write and Erase Guidelines .................................................................. 141
13.3.1.VDD Maintenance and the VDD Monitor ............................................... 141
4
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13.3.2.16.4.2 PSWE Maintenance .................................................................... 142
13.3.3.System Clock ......................................................................................... 142
13.4.Flash Read Timing ......................................................................................... 144
14. Branch Target Cache ........................................................................................... 146
14.1.Cache and Prefetch Operation ....................................................................... 146
14.2.Cache and Prefetch Optimization................................................................... 147
15. External Data Memory Interface and On-Chip XRAM........................................ 154
15.1.Accessing XRAM............................................................................................ 154
15.1.1.16-Bit MOVX Example ........................................................................... 154
15.1.2.8-Bit MOVX Example ............................................................................. 154
15.2.Configuring the External Memory Interface .................................................... 155
15.3.Port Configuration........................................................................................... 155
15.4.Multiplexed and Non-multiplexed Selection.................................................... 158
15.4.1.Multiplexed Configuration....................................................................... 158
15.4.2.Non-multiplexed Configuration............................................................... 159
15.5.Memory Mode Selection................................................................................. 160
15.5.1.Internal XRAM Only ............................................................................... 160
15.5.2.Split Mode without Bank Select.............................................................. 160
15.5.3.Split Mode with Bank Select................................................................... 161
15.5.4.External Only.......................................................................................... 161
15.6.Timing .......................................................................................................... 161
15.6.1.Non-multiplexed Mode ........................................................................... 163
15.6.2.Multiplexed Mode ................................................................................... 166
16. Oscillators ............................................................................................................. 170
16.1.Programmable Internal High-Frequency (H-F) Oscillator ............................... 170
16.1.1. Internal Oscillator Suspend Mode ......................................................... 171
16.2.Programmable Internal Low-Frequency (L-F) Oscillator ................................ 172
16.2.1.Calibrating the Internal L-F Oscillator..................................................... 173
16.3.External Oscillator Drive Circuit...................................................................... 174
16.4.System Clock Selection.................................................................................. 174
16.5.External Crystal Example ............................................................................... 177
16.6.External RC Example ..................................................................................... 178
16.7.External Capacitor Example ........................................................................... 178
16.8.Phase-Locked Loop (PLL).............................................................................. 179
16.8.1.PLL Input Clock and Pre-divider ............................................................ 179
16.8.2.PLL Multiplication and Output Clock ...................................................... 179
16.8.3.Powering on and Initializing the PLL ...................................................... 180
17. Port Input/Output.................................................................................................. 184
17.1.Priority Crossbar Decoder .............................................................................. 186
17.2.Port I/O Initialization ....................................................................................... 188
17.3.General Purpose Port I/O ............................................................................... 191
18. SMBus ................................................................................................................... 203
18.1.Supporting Documents ................................................................................... 204
18.2.SMBus Configuration...................................................................................... 204
Rev. 1.2
5
C8051F360/1/2/3/4/5/6/7/8/9
18.3.SMBus Operation ........................................................................................... 204
18.3.1.Arbitration............................................................................................... 205
18.3.2.Clock Low Extension.............................................................................. 205
18.3.3.SCL Low Timeout................................................................................... 205
18.3.4.SCL High (SMBus Free) Timeout .......................................................... 206
18.4.Using the SMBus............................................................................................ 206
18.4.1.SMBus Configuration Register............................................................... 207
18.4.2.SMB0CN Control Register ..................................................................... 210
18.4.3.Data Register ......................................................................................... 213
18.5.SMBus Transfer Modes.................................................................................. 214
18.5.1.Master Transmitter Mode ....................................................................... 214
18.5.2.Master Receiver Mode ........................................................................... 215
18.5.3.Slave Receiver Mode ............................................................................. 216
18.5.4.Slave Transmitter Mode ......................................................................... 217
18.6.SMBus Status Decoding................................................................................. 218
19. UART0.................................................................................................................... 221
19.1.Enhanced Baud Rate Generation................................................................... 222
19.2.Operational Modes ......................................................................................... 223
19.2.1.8-Bit UART ............................................................................................. 223
19.2.2.9-Bit UART ............................................................................................. 224
19.3.Multiprocessor Communications .................................................................... 225
20. Enhanced Serial Peripheral Interface (SPI0)...................................................... 235
20.1.Signal Descriptions......................................................................................... 236
20.1.1.Master Out, Slave In (MOSI).................................................................. 236
20.1.2.Master In, Slave Out (MISO).................................................................. 236
20.1.3.Serial Clock (SCK) ................................................................................. 236
20.1.4.Slave Select (NSS) ................................................................................ 236
20.2.SPI0 Master Mode Operation ......................................................................... 237
20.3.SPI0 Slave Mode Operation ........................................................................... 239
20.4.SPI0 Interrupt Sources ................................................................................... 239
20.5.Serial Clock Timing......................................................................................... 240
20.6.SPI Special Function Registers ...................................................................... 242
21. Timers.................................................................................................................... 248
21.1.Timer 0 and Timer 1 ....................................................................................... 249
21.1.1.Mode 0: 13-bit Counter/Timer ................................................................ 249
21.1.2.Mode 1: 16-bit Counter/Timer ................................................................ 250
21.1.3.Mode 2: 8-bit Counter/Timer with Auto-Reload...................................... 250
21.1.4.Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)................................. 252
21.2.Timer 2 .......................................................................................................... 257
21.2.1.16-bit Timer with Auto-Reload................................................................ 257
21.2.2.8-bit Timers with Auto-Reload................................................................ 258
21.3.Timer 3 .......................................................................................................... 261
21.3.1.16-bit Timer with Auto-Reload................................................................ 261
21.3.2.8-bit Timers with Auto-Reload................................................................ 262
6
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
22. Programmable Counter Array ............................................................................. 265
22.1.PCA Counter/Timer ........................................................................................ 266
22.2.Capture/Compare Modules ............................................................................ 267
22.2.1.Edge-triggered Capture Mode................................................................ 268
22.2.2.Software Timer (Compare) Mode........................................................... 269
22.2.3.High Speed Output Mode....................................................................... 270
22.2.4.Frequency Output Mode ........................................................................ 271
22.2.5.8-Bit Pulse Width Modulator Mode......................................................... 272
22.2.6.16-Bit Pulse Width Modulator Mode....................................................... 273
22.3.Watchdog Timer Mode ................................................................................... 273
22.3.1.Watchdog Timer Operation .................................................................... 274
22.3.2.Watchdog Timer Usage ......................................................................... 275
22.4.Register Descriptions for PCA0...................................................................... 277
23. Revision Specific Behavior ................................................................................. 282
24. C2 Interface ........................................................................................................... 286
24.1.C2 Interface Registers.................................................................................... 286
24.2.C2 Pin Sharing ............................................................................................... 288
Document Change List ............................................................................................. 289
Contact Information .................................................................................................. 290
Rev. 1.2
7
C8051F360/1/2/3/4/5/6/7/8/9
List of Figures
1. System Overview
Figure 1.1. C8051F360/3 Block Diagram ................................................................. 21
Figure 1.2. C8051F361/4/6/8 Block Diagram ........................................................... 22
Figure 1.3. C8051F362/5/7/9 Block Diagram ........................................................... 22
Figure 1.4. Comparison of Peak MCU Execution Speeds ....................................... 23
Figure 1.5. On-Chip Clock and Reset ......................................................................24
Figure 1.6. On-Board Memory Map ......................................................................... 25
Figure 1.7. Development/In-System Debug Diagram .............................................. 26
Figure 1.8. Digital Crossbar Diagram (Port 0 to Port 3) ........................................... 27
Figure 1.9. PCA Block Diagram ............................................................................... 28
Figure 1.10. PCA Block Diagram .............................................................................28
Figure 1.11. 10-Bit ADC Block Diagram ................................................................... 29
Figure 1.12. Comparator0 Block Diagram ................................................................ 30
Figure 1.13. Comparator1 Block Diagram ................................................................ 31
Figure 1.14. IDA0 Functional Block Diagram ........................................................... 32
2. Absolute Maximum Ratings
3. Global Electrical Characteristics
4. Pinout and Package Definitions
Figure 4.1. TQFP-48 Pinout Diagram (Top View) .................................................... 40
Figure 4.2. TQFP-48 Package Diagram ................................................................... 41
Figure 4.3. LQFP-32 Pinout Diagram (Top View) .................................................... 42
Figure 4.4. LQFP-32 Package Diagram ................................................................... 43
Figure 4.5. QFN-28 Pinout Diagram (Top View) ...................................................... 44
Figure 4.6. QFN-28 Package Drawing ..................................................................... 45
Figure 4.7. Typical QFN-28 Landing Diagram ......................................................... 46
Figure 4.8. QFN-28 Solder Paste Recommendation ............................................... 47
5. 10-Bit ADC (ADC0, C8051F360/1/2/6/7/8/9)
Figure 5.1. ADC0 Functional Block Diagram ........................................................... 48
Figure 5.2. Typical Temperature Sensor Transfer Function .................................... 50
Figure 5.3. Temperature Sensor Error with 1-Point Calibration ............................... 51
Figure 5.4. 10-Bit ADC Track and Conversion Example Timing .............................. 53
Figure 5.5. ADC0 Equivalent Input Circuits .............................................................. 54
Figure 5.6. ADC Window Compare Example: Right-Justified Single-Ended Data ... 61
Figure 5.7. ADC Window Compare Example: Left-Justified Single-Ended Data ..... 61
Figure 5.8. ADC Window Compare Example: Right-Justified Differential Data ....... 62
Figure 5.9. ADC Window Compare Example: Left-Justified Differential Data .......... 62
6. 10-Bit Current Mode DAC (IDA0, C8051F360/1/2/6/7/8/9)
Figure 6.1. IDA0 Functional Block Diagram ............................................................. 64
Figure 6.2. IDA0 Data Word Mapping ......................................................................65
7. Voltage Reference (C8051F360/1/2/6/7/8/9)
Figure 7.1. Voltage Reference Functional Block Diagram ....................................... 68
8. Comparators
Figure 8.1. Comparator0 Functional Block Diagram ................................................ 71
8
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Figure 8.2. Comparator1 Functional Block Diagram ............................................... 72
Figure 8.3. Comparator Hysteresis Plot .................................................................. 73
9. CIP-51 Microcontroller
Figure 9.1. CIP-51 Block Diagram .......................................................................... 82
Figure 9.2. Memory Map ......................................................................................... 87
Figure 9.3. SFR Page Stack .................................................................................... 90
Figure 9.4. SFR Page Stack While Using SFR Page 0x0F To Access OSCICN .... 91
Figure 9.5. SFR Page Stack After ADC0 Window Comparator Interrupt Occurs .... 92
Figure 9.6. SFR Page Stack Upon PCA Interrupt Occurring During an ADC0 ISR . 92
Figure 9.7. SFR Page Stack Upon Return From PCA Interrupt .............................. 93
Figure 9.8. SFR Page Stack Upon Return From ADC2 Window Interrupt .............. 94
10. Interrupt Handler
11. Multiply And Accumulate (MAC0)
Figure 11.1. MAC0 Block Diagram ........................................................................ 118
Figure 11.2. Integer Mode Data Representation ................................................... 119
Figure 11.3. Fractional Mode Data Representation ............................................... 119
Figure 11.4. MAC0 Pipeline ................................................................................... 120
12. Reset Sources
Figure 12.1. Reset Sources ................................................................................... 129
Figure 12.2. Power-On and VDD Monitor Reset Timing ....................................... 130
13. Flash Memory
Figure 13.1. Flash Program Memory Map ............................................................. 139
14. Branch Target Cache
Figure 14.1. Branch Target Cache Data Flow ....................................................... 146
Figure 14.2. Branch Target Cache Organization ................................................... 147
Figure 14.3. Cache Lock Operation ....................................................................... 149
15. External Data Memory Interface and On-Chip XRAM
Figure 15.1. Multiplexed Configuration Example ................................................... 158
Figure 15.2. Non-multiplexed Configuration Example ........................................... 159
Figure 15.3. EMIF Operating Modes ..................................................................... 160
Figure 15.4. Non-multiplexed 16-bit MOVX Timing ............................................... 163
Figure 15.5. Non-multiplexed 8-bit MOVX without Bank Select Timing ................ 164
Figure 15.6. Non-multiplexed 8-bit MOVX with Bank Select Timing ..................... 165
Figure 15.7. Multiplexed 16-bit MOVX Timing ....................................................... 166
Figure 15.8. Multiplexed 8-bit MOVX without Bank Select Timing ........................ 167
Figure 15.9. Multiplexed 8-bit MOVX with Bank Select Timing ............................. 168
16. Oscillators
Figure 16.1. Oscillator Diagram ............................................................................. 170
Figure 16.2. 32.768 kHz External Crystal Example ............................................... 177
Figure 16.3. PLL Block Diagram ............................................................................ 179
17. Port Input/Output
Figure 17.1. Port I/O Functional Block Diagram (Port 0 through Port 3) ............... 184
Figure 17.2. Port I/O Cell Block Diagram .............................................................. 185
Figure 17.3. Crossbar Priority Decoder with No Pins Skipped .............................. 186
Figure 17.4. Crossbar Priority Decoder with Port Pins Skipped ............................ 187
Rev. 1.2
9
C8051F360/1/2/3/4/5/6/7/8/9
18. SMBus
Figure 18.1. SMBus Block Diagram ...................................................................... 203
Figure 18.2. Typical SMBus Configuration ............................................................ 204
Figure 18.3. SMBus Transaction ........................................................................... 205
Figure 18.4. Typical SMBus SCL Generation ........................................................ 208
Figure 18.5. Typical Master Transmitter Sequence ............................................... 214
Figure 18.6. Typical Master Receiver Sequence ................................................... 215
Figure 18.7. Typical Slave Receiver Sequence ..................................................... 216
Figure 18.8. Typical Slave Transmitter Sequence ................................................. 217
19. UART0
Figure 19.1. UART0 Block Diagram ...................................................................... 221
Figure 19.2. UART0 Baud Rate Logic ................................................................... 222
Figure 19.3. UART Interconnect Diagram ............................................................. 223
Figure 19.4. 8-Bit UART Timing Diagram .............................................................. 223
Figure 19.5. 9-Bit UART Timing Diagram .............................................................. 224
Figure 19.6. UART Multi-Processor Mode Interconnect Diagram ......................... 225
20. Enhanced Serial Peripheral Interface (SPI0)
Figure 20.1. SPI Block Diagram ............................................................................ 235
Figure 20.2. Multiple-Master Mode Connection Diagram ...................................... 238
Figure 20.3. 3-Wire Single Master and 3-Wire Single Slave Mode
Connection Diagram ......................................................................... 238
Figure 20.4. 4-Wire Single Master Mode and 4-Wire Slave Mode
Connection Diagram ......................................................................... 238
Figure 20.5. Master Mode Data/Clock Timing ....................................................... 240
Figure 20.6. Slave Mode Data/Clock Timing (CKPHA = 0) ................................... 241
Figure 20.7. Slave Mode Data/Clock Timing (CKPHA = 1) ................................... 241
Figure 20.8. SPI Master Timing (CKPHA = 0) ....................................................... 245
Figure 20.9. SPI Master Timing (CKPHA = 1) ....................................................... 245
Figure 20.10. SPI Slave Timing (CKPHA = 0) ....................................................... 246
Figure 20.11. SPI Slave Timing (CKPHA = 1) ....................................................... 246
21. Timers
Figure 21.1. T0 Mode 0 Block Diagram ................................................................. 250
Figure 21.2. T0 Mode 2 Block Diagram ................................................................. 251
Figure 21.3. T0 Mode 3 Block Diagram ................................................................. 252
Figure 21.4. Timer 2 16-Bit Mode Block Diagram ................................................. 257
Figure 21.5. Timer 2 8-Bit Mode Block Diagram ................................................... 258
Figure 21.6. Timer 3 16-Bit Mode Block Diagram ................................................. 261
Figure 21.7. Timer 3 8-Bit Mode Block Diagram ................................................... 262
22. Programmable Counter Array
Figure 22.1. PCA Block Diagram ........................................................................... 265
Figure 22.2. PCA Counter/Timer Block Diagram ................................................... 266
Figure 22.3. PCA Interrupt Block Diagram ............................................................ 267
Figure 22.4. PCA Capture Mode Diagram ............................................................. 268
Figure 22.5. PCA Software Timer Mode Diagram ................................................. 269
Figure 22.6. PCA High Speed Output Mode Diagram ........................................... 270
10
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Figure 22.7. PCA Frequency Output Mode ........................................................... 271
Figure 22.8. PCA 8-Bit PWM Mode Diagram ........................................................ 272
Figure 22.9. PCA 16-Bit PWM Mode ..................................................................... 273
Figure 22.10. PCA Module 5 with Watchdog Timer Enabled ................................ 274
23. Revision Specific Behavior
Figure 23.1. Device Package - TQFP 48 ............................................................... 282
Figure 23.2. Device Package - LQFP 32 ............................................................... 283
Figure 23.3. Device Package - QFN 28 ................................................................. 283
24. C2 Interface
Figure 24.1. Typical C2 Pin Sharing ...................................................................... 288
Rev. 1.2
11
C8051F360/1/2/3/4/5/6/7/8/9
List of Tables
1. System Overview
Table 1.1. Product Selection Guide ......................................................................... 19
Table 1.2. Product Selection Guide (These OPNs are Not Recommended for New
Designs) ............................................................................................... 20
2. Absolute Maximum Ratings
Table 2.1. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3. Global Electrical Characteristics
Table 3.1. Global Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 3.2. Index to Electrical Characteristics Tables ............................................... 36
4. Pinout and Package Definitions
Table 4.1. Pin Definitions for the C8051F36x .......................................................... 37
Table 4.2. TQFP-48 Package Dimensions .............................................................. 41
Table 4.3. LQFP-32 Package Dimensions .............................................................. 43
Table 4.4. QFN-28 Package Dimensions ................................................................ 45
5. 10-Bit ADC (ADC0, C8051F360/1/2/6/7/8/9)
Table 5.1. ADC0 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6. 10-Bit Current Mode DAC (IDA0, C8051F360/1/2/6/7/8/9)
Table 6.1. IDAC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7. Voltage Reference (C8051F360/1/2/6/7/8/9)
Table 7.1. Voltage Reference Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . 70
8. Comparators
Table 8.1. Comparator Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 80
9. CIP-51 Microcontroller
Table 9.1. CIP-51 Instruction Set Summary ............................................................ 83
Table 9.2. Special Function Register (SFR) Memory Map ...................................... 97
Table 9.3. Special Function Registers ..................................................................... 98
10. Interrupt Handler
Table 10.1. Interrupt Summary .............................................................................. 109
11. Multiply And Accumulate (MAC0)
Table 11.1. MAC0 Rounding (MAC0SAT = 0) ....................................................... 121
12. Reset Sources
Table 12.1. Reset Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
13. Flash Memory
Table 13.1. Flash Security Summary .................................................................... 140
Table 13.2. Flash Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
14. Branch Target Cache
15. External Data Memory Interface and On-Chip XRAM
Table 15.1. EMIF Pinout (C8051F360/3) ............................................................... 156
Table 15.2. AC Parameters for External Memory Interface ................................... 169
16. Oscillators
Table 16.1. Internal High Frequency Oscillator Electrical Characteristics . . . . . . . 172
Table 16.2. Internal Low Frequency Oscillator Electrical Characteristics . . . . . . . 173
12
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C8051F360/1/2/3/4/5/6/7/8/9
Table 16.3. PLL Frequency Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Table 16.4. PLL Lock Timing Characteristics ........................................................ 183
17. Port Input/Output
Table 17.1. Port I/O DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 202
18. SMBus
Table 18.1. SMBus Clock Source Selection .......................................................... 207
Table 18.2. Minimum SDA Setup and Hold Times ................................................ 208
Table 18.3. Sources for Hardware Changes to SMB0CN ..................................... 212
Table 18.4. SMBus Status Decoding ..................................................................... 218
19. UART0
Table 19.1. Timer Settings for Standard Baud Rates
Using The Internal 24.5 MHz Oscillator .............................................. 228
Table 19.2. Timer Settings for Standard Baud Rates
Using an External 25.0 MHz Oscillator ............................................... 229
Table 19.3. Timer Settings for Standard Baud Rates
Using an External 22.1184 MHz Oscillator ......................................... 230
Table 19.4. Timer Settings for Standard Baud Rates
Using an External 18.432 MHz Oscillator ........................................... 231
Table 19.5. Timer Settings for Standard Baud Rates
Using an External 11.0592 MHz Oscillator ......................................... 232
Table 19.6. Timer Settings for Standard Baud Rates
Using an External 3.6864 MHz Oscillator ........................................... 233
Table 19.7. Timer Settings for Standard Baud Rates Using the PLL .................... 234
Table 19.8. Timer Settings for Standard Baud Rates Using the PLL .................... 234
20. Enhanced Serial Peripheral Interface (SPI0)
Table 20.1. SPI Slave Timing Parameters ............................................................ 247
21. Timers
22. Programmable Counter Array
Table 22.1. PCA Timebase Input Options ............................................................. 266
Table 22.2. PCA0CPM Register Settings for PCA Capture/Compare Modules .... 268
Table 22.3. Watchdog Timer Timeout Intervals1 ................................................... 276
23. Revision Specific Behavior
24. C2 Interface
Rev. 1.2
13
C8051F360/1/2/3/4/5/6/7/8/9
List of Registers
SFR Definition 5.1. AMX0P: AMUX0 Positive Channel Select . . . . . . . . . . . . . . . . . . . 55
SFR Definition 5.2. AMX0N: AMUX0 Negative Channel Select . . . . . . . . . . . . . . . . . . 56
SFR Definition 5.3. ADC0CF: ADC0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
SFR Definition 5.4. ADC0H: ADC0 Data Word MSB . . . . . . . . . . . . . . . . . . . . . . . . . . 57
SFR Definition 5.5. ADC0L: ADC0 Data Word LSB . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
SFR Definition 5.6. ADC0CN: ADC0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
SFR Definition 5.7. ADC0GTH: ADC0 Greater-Than Data High Byte . . . . . . . . . . . . . 59
SFR Definition 5.8. ADC0GTL: ADC0 Greater-Than Data Low Byte . . . . . . . . . . . . . . 59
SFR Definition 5.9. ADC0LTH: ADC0 Less-Than Data High Byte . . . . . . . . . . . . . . . . 60
SFR Definition 5.10. ADC0LTL: ADC0 Less-Than Data Low Byte . . . . . . . . . . . . . . . . 60
SFR Definition 6.1. IDA0CN: IDA0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
SFR Definition 6.2. IDA0H: IDA0 Data Word MSB . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
SFR Definition 6.3. IDA0L: IDA0 Data Word LSB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
SFR Definition 7.1. REF0CN: Reference Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
SFR Definition 8.1. CPT0CN: Comparator0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
SFR Definition 8.2. CPT0MX: Comparator0 MUX Selection . . . . . . . . . . . . . . . . . . . . 75
SFR Definition 8.3. CPT0MD: Comparator0 Mode Selection . . . . . . . . . . . . . . . . . . . . 76
SFR Definition 8.4. CPT1CN: Comparator1 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
SFR Definition 8.5. CPT1MX: Comparator1 MUX Selection . . . . . . . . . . . . . . . . . . . . 78
SFR Definition 8.6. CPT1MD: Comparator1 Mode Selection . . . . . . . . . . . . . . . . . . . . 79
SFR Definition 9.1. SFR0CN: SFR Page Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
SFR Definition 9.2. SFRPAGE: SFR Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
SFR Definition 9.3. SFRNEXT: SFR Next Register . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
SFR Definition 9.4. SFRLAST: SFR Last Register . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
SFR Definition 9.5. SP: Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
SFR Definition 9.6. DPL: Data Pointer Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
SFR Definition 9.7. DPH: Data Pointer High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
SFR Definition 9.8. PSW: Program Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
SFR Definition 9.9. ACC: Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
SFR Definition 9.10. B: B Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
SFR Definition 9.11. PCON: Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
SFR Definition 10.1. IE: Interrupt Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
SFR Definition 10.2. IP: Interrupt Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
SFR Definition 10.3. EIE1: Extended Interrupt Enable 1 . . . . . . . . . . . . . . . . . . . . . . 113
SFR Definition 10.4. EIP1: Extended Interrupt Priority 1 . . . . . . . . . . . . . . . . . . . . . . 114
SFR Definition 10.5. EIE2: Extended Interrupt Enable 2 . . . . . . . . . . . . . . . . . . . . . . 115
SFR Definition 10.6. EIP2: Extended Interrupt Priority 2 . . . . . . . . . . . . . . . . . . . . . . 115
SFR Definition 10.7. IT01CF: INT0/INT1 Configuration . . . . . . . . . . . . . . . . . . . . . . . 117
SFR Definition 11.1. MAC0CF: MAC0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 123
SFR Definition 11.2. MAC0STA: MAC0 Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
SFR Definition 11.3. MAC0AH: MAC0 A High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . 124
SFR Definition 11.4. MAC0AL: MAC0 A Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . 125
SFR Definition 11.5. MAC0BH: MAC0 B High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . 125
14
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 11.6. MAC0BL: MAC0 B Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
SFR Definition 11.7. MAC0ACC3: MAC0 Accumulator Byte 3 . . . . . . . . . . . . . . . . . . 126
SFR Definition 11.8. MAC0ACC2: MAC0 Accumulator Byte 2 . . . . . . . . . . . . . . . . . 126
SFR Definition 11.9. MAC0ACC1: MAC0 Accumulator Byte 1 . . . . . . . . . . . . . . . . . 126
SFR Definition 11.10. MAC0ACC0: MAC0 Accumulator Byte 0 . . . . . . . . . . . . . . . . . 127
SFR Definition 11.11. MAC0OVR: MAC0 Accumulator Overflow . . . . . . . . . . . . . . . . 127
SFR Definition 11.12. MAC0RNDH: MAC0 Rounding Register High Byte . . . . . . . . . 127
SFR Definition 11.13. MAC0RNDL: MAC0 Rounding Register Low Byte . . . . . . . . . 128
SFR Definition 12.1. VDM0CN: VDD Monitor Control . . . . . . . . . . . . . . . . . . . . . . . . 132
SFR Definition 12.2. RSTSRC: Reset Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
SFR Definition 13.1. PSCTL: Program Store Read/Write Control . . . . . . . . . . . . . . . 143
SFR Definition 13.2. FLKEY: Flash Lock and Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
SFR Definition 13.3. FLSCL: Flash Memory Control . . . . . . . . . . . . . . . . . . . . . . . . . 144
SFR Definition 14.1. CCH0CN: Cache Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
SFR Definition 14.2. CCH0TN: Cache Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
SFR Definition 14.3. CCH0LC: Cache Lock Control . . . . . . . . . . . . . . . . . . . . . . . . . 152
SFR Definition 14.4. CCH0MA: Cache Miss Accumulator . . . . . . . . . . . . . . . . . . . . . 153
SFR Definition 14.5. FLSTAT: Flash Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
SFR Definition 15.1. EMI0CN: External Memory Interface Control . . . . . . . . . . . . . . 156
SFR Definition 15.2. EMI0CF: External Memory Configuration . . . . . . . . . . . . . . . . . 157
SFR Definition 15.3. EMI0TC: External Memory Timing Control . . . . . . . . . . . . . . . . 162
SFR Definition 16.1. OSCICL: Internal Oscillator Calibration. . . . . . . . . . . . . . . . . . . 171
SFR Definition 16.2. OSCICN: Internal Oscillator Control . . . . . . . . . . . . . . . . . . . . . 172
SFR Definition 16.3. OSCLCN: Internal L-F Oscillator Control . . . . . . . . . . . . . . . . . . 173
SFR Definition 16.4. CLKSEL: System Clock Selection . . . . . . . . . . . . . . . . . . . . . . . 175
SFR Definition 16.5. OSCXCN: External Oscillator Control . . . . . . . . . . . . . . . . . . . . 176
SFR Definition 16.6. PLL0CN: PLL Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
SFR Definition 16.7. PLL0DIV: PLL Pre-divider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
SFR Definition 16.8. PLL0MUL: PLL Clock Scaler . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
SFR Definition 16.9. PLL0FLT: PLL Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
SFR Definition 17.1. XBR0: Port I/O Crossbar Register 0 . . . . . . . . . . . . . . . . . . . . . 189
SFR Definition 17.2. XBR1: Port I/O Crossbar Register 1 . . . . . . . . . . . . . . . . . . . . . 190
SFR Definition 17.3. P0: Port0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
SFR Definition 17.4. P0MDIN: Port0 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
SFR Definition 17.5. P0MDOUT: Port0 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . . 192
SFR Definition 17.6. P0SKIP: Port0 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
SFR Definition 17.7. P0MAT: Port0 Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
SFR Definition 17.8. P0MASK: Port0 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
SFR Definition 17.9. P1: Port1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
SFR Definition 17.10. P1MDIN: Port1 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
SFR Definition 17.11. P1MDOUT: Port1 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . 195
SFR Definition 17.12. P1SKIP: Port1 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
SFR Definition 17.13. P1MAT: Port1 Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
SFR Definition 17.14. P1MASK: Port1 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
SFR Definition 17.15. P2: Port2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Rev. 1.2
15
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.16. P2MDIN: Port2 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
SFR Definition 17.17. P2MDOUT: Port2 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . 197
SFR Definition 17.18. P2SKIP: Port2 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
SFR Definition 17.19. P2MAT: Port2 Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
SFR Definition 17.20. P2MASK: Port2 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
SFR Definition 17.21. P3: Port3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
SFR Definition 17.22. P3MDIN: Port3 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
SFR Definition 17.23. P3MDOUT: Port3 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . 200
SFR Definition 17.24. P3SKIP: Port3 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
SFR Definition 17.25. P4: Port4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
SFR Definition 17.26. P4MDOUT: Port4 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . 201
SFR Definition 18.1. SMB0CF: SMBus Clock/Configuration . . . . . . . . . . . . . . . . . . . 209
SFR Definition 18.2. SMB0CN: SMBus Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
SFR Definition 18.3. SMB0DAT: SMBus Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
SFR Definition 19.1. SCON0: Serial Port 0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . 226
SFR Definition 19.2. SBUF0: Serial (UART0) Port Data Buffer . . . . . . . . . . . . . . . . . 227
SFR Definition 20.1. SPI0CFG: SPI0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 242
SFR Definition 20.2. SPI0CN: SPI0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
SFR Definition 20.3. SPI0CKR: SPI0 Clock Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
SFR Definition 20.4. SPI0DAT: SPI0 Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
SFR Definition 21.1. TCON: Timer Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
SFR Definition 21.2. TMOD: Timer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
SFR Definition 21.3. CKCON: Clock Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
SFR Definition 21.4. TL0: Timer 0 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
SFR Definition 21.5. TL1: Timer 1 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
SFR Definition 21.6. TH0: Timer 0 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
SFR Definition 21.7. TH1: Timer 1 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
SFR Definition 21.8. TMR2CN: Timer 2 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
SFR Definition 21.9. TMR2RLL: Timer 2 Reload Register Low Byte . . . . . . . . . . . . . 260
SFR Definition 21.10. TMR2RLH: Timer 2 Reload Register High Byte . . . . . . . . . . . 260
SFR Definition 21.11. TMR2L: Timer 2 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
SFR Definition 21.12. TMR2H Timer 2 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
SFR Definition 21.13. TMR3CN: Timer 3 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
SFR Definition 21.14. TMR3RLL: Timer 3 Reload Register Low Byte . . . . . . . . . . . . 264
SFR Definition 21.15. TMR3RLH: Timer 3 Reload Register High Byte . . . . . . . . . . . 264
SFR Definition 21.16. TMR3L: Timer 3 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
SFR Definition 21.17. TMR3H Timer 3 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
SFR Definition 22.1. PCA0CN: PCA Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
SFR Definition 22.2. PCA0MD: PCA0 Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
SFR Definition 22.3. PCA0CPMn: PCA0 Capture/Compare Mode . . . . . . . . . . . . . . 279
SFR Definition 22.4. PCA0L: PCA0 Counter/Timer Low Byte . . . . . . . . . . . . . . . . . . 280
SFR Definition 22.5. PCA0H: PCA0 Counter/Timer High Byte . . . . . . . . . . . . . . . . . . 280
SFR Definition 22.6. PCA0CPLn: PCA0 Capture Module Low Byte . . . . . . . . . . . . . . 280
SFR Definition 22.7. PCA0CPHn: PCA0 Capture Module High Byte . . . . . . . . . . . . 281
C2 Register Definition 24.1. C2ADD: C2 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
16
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
C2 Register Definition 24.2. DEVICEID: C2 Device ID . . . . . . . . . . . . . . . . . . . . . . . . 286
C2 Register Definition 24.3. REVID: C2 Revision ID . . . . . . . . . . . . . . . . . . . . . . . . . 287
C2 Register Definition 24.4. FPCTL: C2 Flash Programming Control . . . . . . . . . . . . 287
C2 Register Definition 24.5. FPDAT: C2 Flash Programming Data . . . . . . . . . . . . . . 287
Rev. 1.2
17
C8051F360/1/2/3/4/5/6/7/8/9
1.
System Overview
C8051F36x devices are fully integrated mixed-signal System-on-a-Chip MCUs. Highlighted features are
listed below. Refer to Table 1.1 for specific product feature selection.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
High-speed pipelined 8051-compatible microcontroller core (up to 100 MIPS)
In-system, full-speed, non-intrusive debug interface (on-chip)
True 10-bit 200 ksps 16-channel single-ended/differential ADC with analog multiplexer
10-bit Current Output DAC
2-cycle 16 by 16 Multiply and Accumulate Engine
Precision programmable 25 MHz internal oscillator
Up to 32 kB of on-chip Flash memory—1024 bytes are reserved
1024 bytes of on-chip RAM
External Data Memory Interface with 64 kB address space
SMBus/I2C, Enhanced UART, and Enhanced SPI serial interfaces implemented in hardware
Four general-purpose 16-bit timers
Programmable Counter/Timer Array (PCA) with six capture/compare modules and Watchdog Timer
function
On-chip Power-On Reset, VDD Monitor, and Temperature Sensor
Two on-chip Voltage Comparators
up to 39 Port I/O (5 V tolerant)
With on-chip Power-On Reset, VDD Monitor, Watchdog Timer, and clock oscillator, the C8051F36x devices
are truly stand-alone System-on-a-Chip solutions. The Flash memory can be reprogrammed even in-circuit, providing non-volatile data storage, and also allowing field upgrades of the 8051 firmware. User software has complete control of all peripherals, and may individually shut down any or all peripherals for
power savings.
The on-chip Silicon Labs 2-Wire (C2) Development Interface allows non-intrusive (uses no on-chip
resources), full speed, in-circuit debugging using the production MCU installed in the final application. This
debug logic supports inspection and modification of memory and registers, setting breakpoints, single
stepping, run and halt commands. All analog and digital peripherals are fully functional while debugging
using C2. The two C2 interface pins can be shared with user functions, allowing in-system debugging without occupying package pins.
Each device is specified for 3.0 to 3.6 V (100 MIPS) operation or 2.7 to 3.6 V (50 MIPS) operation over the
industrial temperature range (–40 to +85 °C). The Port I/O and RST pins are tolerant of input signals up to
5 V. The C8051F36x devices are available in 48-pin TQFP packages, and C8051F36x devices are available in 32-pin LQFP and 28-pin QFN packages (also referred to as MLP or MLF packages). All package
types are lead-free (RoHS compliant). See Table 1.1 for ordering part numbers. Block diagrams are
included in Figure 1.1, Figure 1.2, and Figure 1.3.
18
Rev. 1.2
MIPS (Peak)
Flash Memory (kB)
Calibrated Internal 24.5 MHz Oscillator
Internal 80 kHz Oscillator
External Memory Interface
SMBus/I2C
Enhanced SPI
UART
Timers (16-bit)
Programmable Counter Array
Digital Port I/Os
10-bit 200ksps ADC
10-bit Current Output DAC
Internal Voltage Reference
Temperature Sensor
Analog Comparators
Lead-free (RoHS Compliant)
C8051F360-C-GQ
100
32 1024
4
39
2
TQFP-48
C8051F361-C-GQ1
100
32 1024
—
4
29
2
LQFP-32
C8051F362-C-GM2
100
32 1024
—
4
25
2
Rev. 1.2
Package
2-cycle 16 by 16 MAC
RAM (bytes)
Ordering Part Number
C8051F360/1/2/3/4/5/6/7/8/9
Table 1.1. Product Selection Guide
QFN-28
Notes:
1. Pin compatible with the C8051F310-GQ.
2. Pin compatible with the C8051F311-GM.
19
C8051F360/1/2/3/4/5/6/7/8/9
Internal 80 kHz Oscillator
External Memory Interface
SMBus/I2C
Enhanced SPI
UART
Timers (16-bit)
Programmable Counter Array
Digital Port I/Os
10-bit Current Output DAC
Internal Voltage Reference
Temperature Sensor
Analog Comparators
Lead-free (RoHS Compliant)
4
39 —
—
—
—
2
TQFP-48
C8051F364-C-GQ1
100
32 1024
—
4
29 —
—
—
—
2
LQFP-32
C8051F365-C-GM2
100
32 1024
—
4
25 —
—
—
—
2
C8051F366-C-GQ1
50
32 1024
—
4
29
2
LQFP-32
C8051F367-C-GM2
50
32 1024
—
4
25
2
C8051F368-C-GQ1
50
16 1024
—
4
29
2
LQFP-32
C8051F369-C-GM2
50
16 1024
—
4
25
2
Notes:
1. Pin compatible with the C8051F310-GQ.
2. Pin compatible with the C8051F311-GM.
20
Rev. 1.2
Package
Calibrated Internal 24.5 MHz Oscillator
32 1024
10-bit 200ksps ADC
Flash Memory (kB)
100
2-cycle 16 by 16 MAC
MIPS (Peak)
C8051F363-C-GQ
RAM (bytes)
Ordering Part Number
Table 1.2. Product Selection Guide (These OPNs are Not Recommended for New Designs)
QFN-28
QFN-28
QFN-28
C8051F360/1/2/3/4/5/6/7/8/9
C2D
Port I/O Configuration
Debug / Programming
Hardware
C2CK/RST
Digital Peripherals
Reset
Power-On
Reset
Supply
Monitor
VDD
Power
Net
CIP-51 8051
Controller Core
UART0
Timers 0, 1,
2, 3
32/16 kB ISP FLASH
Program Memory
PCA/WDT
256 Byte RAM
2-cycle 16 by 16 Multiply
and Accumulate
System Clock Setup
XTAL1
XTAL2
External
Oscillator
Internal
Oscillator
P0.0
P0.1/TX
P0.2/RX
P0.3/VREF
P0.4/IDA0
P0.5/XTAL1
P0.6/XTAL2
P0.7/CNVSTR
Port 1
Drivers
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
Port 2
Drivers
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
Port 3
Drivers
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
Port 4
Drivers
P4.0
P4.1
P4.2
P4.3
P4.4
P4.5
P4.6/C2D
SMBus
SPI
1 kB XRAM
GND
Priority
Crossbar
Decoder
Port 0
Drivers
Crossbar Control
SFR
Bus
External Memory
Interface
P0 / P4
Control
P2 / P3 / P4
Address
Clock
Multiplier
P1
Data
Analog Peripherals
Low Frequency Oscillator
CP0
VREF
VDD
10-bit
IDAC
VREF
10-bit
200 ksps
ADC
A
M
U
X
P4.4
CP1
+
+
-
2 Comparators
AIN0–AIN16
VDD
Temp
Sensor
C8051F360 only
Figure 1.1. C8051F360/3 Block Diagram
Rev. 1.2
21
C8051F360/1/2/3/4/5/6/7/8/9
C2D
Port I/O Configuration
Debug / Programming
Hardware
C2CK/RST
Digital Peripherals
Reset
Power-On
Reset
Supply
Monitor
VDD
CIP-51 8051
Controller Core
UART0
Timers 0, 1,
2, 3
32/16 kB ISP FLASH
Program Memory
PCA/WDT
256 Byte RAM
2-cycle 16 by 16 Multiply
and Accumulate
SPI
Crossbar Control
SFR
Bus
System Clock Setup
XTAL1
XTAL2
External
Oscillator
Internal
Oscillator
Port 1
Drivers
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
Port 2
Drivers
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
Port 3
Drivers
P3.0/C2D
P3.1
P3.2
P3.3
P3.4
SMBus
1 kB XRAM
GND
Priority
Crossbar
Decoder
Port 0
Drivers
P0.0/VREF
P0.1/IDA0
P0.2/XTAL1
P0.3/XTAL2
P0.4/TX
P0.5/RX
P0.6/CNVSTR
P0.7
Analog Peripherals
CP0
VREF
Clock
Multiplier
10-bit
IDAC
VDD
Low Frequency Oscillator
+
-
2 Comparators
VREF
AIN0–AIN20
A
M
U
X
10-bit
200 ksps
ADC
+
-
CP1
P0.1
VDD
Temp
Sensor
C8051F361/6/8 only
Figure 1.2. C8051F361/4/6/8 Block Diagram
C2D
Port I/O Configuration
Debug / Programming
Hardware
C2CK/RST
Digital Peripherals
Reset
Power-On
Reset
Supply
Monitor
VDD
CIP-51 8051
Controller Core
UART0
Timers 0, 1,
2, 3
32/16 kB ISP FLASH
Program Memory
PCA/WDT
256 Byte RAM
1 kB XRAM
GND
2-cycle 16 by 16 Multiply
and Accumulate
External
Oscillator
SPI
SFR
Bus
Crossbar Control
Internal
Oscillator
Low Frequency Oscillator
Port 2
Drivers
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
Port 3
Drivers
P3.0/C2D
CP0
VDD
10-bit
IDAC
VREF
10-bit
200 ksps
ADC
A
M
U
X
P0.1
CP1
+
-
AIN0–AIN20
VDD
Temp
Sensor
Figure 1.3. C8051F362/5/7/9 Block Diagram
Rev. 1.2
+
-
2 Comparators
C8051F362/7/9 only
22
Port 1
Drivers
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
Analog Peripherals
VREF
Clock
Multiplier
P0.0/VREF
P0.1/IDA0
P0.2/XTAL1
P0.3/XTAL2
P0.4/TX
P0.5/RX
P0.6/CNVSTR
P0.7
SMBus
System Clock Setup
XTAL1
XTAL2
Priority
Crossbar
Decoder
Port 0
Drivers
C8051F360/1/2/3/4/5/6/7/8/9
1.1.
CIP-51™ Microcontroller Core
1.1.1. Fully 8051 Compatible
The C8051F36x family utilizes Silicon Labs' proprietary CIP-51 microcontroller core. The CIP-51 is fully
compatible with the MCS-51™ instruction set; standard 803x/805x assemblers and compilers can be used
to develop software. The CIP-51 core offers all the peripherals included with a standard 8052, including
four 16-bit counter/timers, a full-duplex UART with extended baud rate configuration, an enhanced SPI
port, 1024 bytes of internal RAM, 128 byte Special Function Register (SFR) address space, and up to 39
I/O pins.
1.1.2. Improved Throughput
The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system
clock cycles to execute with a maximum system clock of 12-to-24 MHz. By contrast, the CIP-51 core executes 70% of its instructions in one or two system clock cycles, with only four instructions taking more than
four system clock cycles.
The CIP-51 has a total of 109 instructions. The table below shows the total number of instructions that
require each execution time.
Clocks to Execute
1
2
2/3
3
3/4
4
4/5
5
8
Number of Instructions
26
50
5
14
7
3
1
2
1
With the CIP-51's maximum system clock at 100 MHz, it has a peak throughput of 100 MIPS. Figure 1.4
shows a comparison of peak throughputs for various 8-bit microcontroller cores with their maximum system clocks.
25
MIPS
20
15
10
5
Silicon Labs
Microchip
Philips
ADuC812
CIP-51
PIC17C75x
80C51
8051
(25 MHz clk) (33 MHz clk) (33 MHz clk) (16 MHz clk)
Figure 1.4. Comparison of Peak MCU Execution Speeds
Rev. 1.2
23
C8051F360/1/2/3/4/5/6/7/8/9
1.1.3. Additional Features
The C8051F36x SoC family includes several key enhancements to the CIP-51 core and peripherals to
improve performance and ease of use in end applications.
The extended interrupt handler provides 16 interrupt sources into the CIP-51 (as opposed to 7 for the standard 8051), allowing numerous analog and digital peripherals to interrupt the controller. An interrupt driven
system requires less intervention by the MCU, giving it more effective throughput. The extra interrupt
sources are very useful when building multi-tasking, real-time systems.
Eight reset sources are available: power-on reset circuitry (POR), an on-chip VDD Monitor (forces reset
when power supply voltage drops below VRST as given in Table 12.1 on page 135), a Watchdog Timer, a
Missing Clock Detector, a voltage level detection from Comparator0, a forced software reset, an external
reset pin, and an illegal Flash access protection circuit. Each reset source except for the POR, Reset Input
Pin, or Flash error may be disabled by the user in software. The WDT may be permanently enabled in software after a power-on reset during MCU initialization.
The internal oscillator factory calibrated to 24.5 MHz ±2%. This internal oscillator period may be user programmed in ~0.5% increments. An additional low-frequency oscillator is also available which facilitates
low-power operation. An external oscillator drive circuit is included, allowing an external crystal, ceramic
resonator, capacitor, RC, or CMOS clock source to generate the system clock. If desired, the system clock
source may be switched on-the-fly between both internal and external oscillator circuits. An external oscillator can also be extremely useful in low power applications, allowing the MCU to run from a slow (power
saving) source, while periodically switching to the fast (up to 25 MHz) internal oscillator as needed. Additionally, an on-chip PLL is provided to achieve higher system clock speeds for increased throughput.
VDD
Power On
Reset
Supply
Monitor
Px.x
Px.x
+
-
Comparator 0
+
-
'0'
Enable
C0RSEF
Missing
Clock
Detector
(oneshot)
EN
Reset
Funnel
PCA
WDT
(Software Reset)
SWRSF
Low
Frequency
Oscillator
Errant
FLASH
Operation
Internal
Oscillator
WDT
Enable
MCD
Enable
EN
System
Clock
CIP-51
Microcontroller
Core
PLL
Circuitry
XTAL1
XTAL2
External
Oscillator
Drive
System Reset
Clock Select
Extended Interrupt
Handler
Figure 1.5. On-Chip Clock and Reset
24
(wired-OR)
Rev. 1.2
/RST
C8051F360/1/2/3/4/5/6/7/8/9
1.2.
On-Chip Memory
The CIP-51 has a standard 8051 program and data address configuration. It includes 256 bytes of data
RAM, with the upper 128 bytes dual-mapped. Indirect addressing accesses the upper 128 bytes of general
purpose RAM, and direct addressing accesses the 128 byte SFR address space. The lower 128 bytes of
RAM are accessible via direct and indirect addressing. The first 32 bytes are addressable as four banks of
general purpose registers, and the next 16 bytes can be byte addressable or bit addressable.
Program memory consists of 32/16 kB of Flash. This memory may be reprogrammed in-system in 1024
byte sectors, and requires no special off-chip programming voltage. See Figure 1.6 for the MCU system
memory map.
PROGRAM MEMORY
DATA MEMORY
INTERNAL DATA ADDRESS SPACE
C8051F360/1/2/3/4/5/6/7
RESERVED
0xFF
0x80
0x7F
0x7C00
0x7BFF
Upper 128 RAM
(Indirect Addressing
Only)
(Direct and Indirect
Addressing)
FLASH
0x30
0x2F
(In-System
Programmable in 1024
Byte Sectors)
0x20
0x1F
0x00
Bit Addressable
Special Function
Register's
(Direct Addressing Only)
Lower 128 RAM
(Direct and Indirect
Addressing)
General Purpose
Registers
0x0000
EXTERNAL DATA ADDRESS SPACE
C8051F368/9
0xFFFF
RESERVED
0x4000
0x3FFF
Same 1024 bytes as from
0x0000 to 0x03FF, wrapped
on 1024-byte boundaries
FLASH
(In-System
Programmable in 1024
Byte Sectors)
0x0400
0x03FF
0x0000
0x0000
XRAM - 1024 Bytes
(accessable using MOVX
instruction)
Figure 1.6. On-Board Memory Map
1.3.
On-Chip Debug Circuitry
The C8051F36x devices include on-chip Silicon Labs 2-Wire (C2) debug circuitry that provides non-intrusive, full speed, in-circuit debugging of the production part installed in the end application.
Silicon Labs' debugging system supports inspection and modification of memory and registers, breakpoints, and single stepping. No additional target RAM, program memory, timers, or communications chan-
Rev. 1.2
25
C8051F360/1/2/3/4/5/6/7/8/9
nels are required. All the digital and analog peripherals are functional and work correctly while debugging.
All the peripherals (except for the ADC and SMBus) are stalled when the MCU is halted, during single
stepping, or at a breakpoint in order to keep them synchronized.
The C8051F360DK development kit provides all the hardware and software necessary to develop application code and perform in-circuit debugging with the C8051F36x MCUs. The kit includes software with a
developer's studio and debugger, an integrated 8051 assembler, and a debug adapter. It also has a target
application board with the associated MCU installed and prototyping area, plus the required cables, and
wall-mount power supply. The Development Kit requires a PC running Windows98SE or later.
The Silicon Labs IDE interface is a vastly superior developing and debugging configuration, compared to
standard MCU emulators that use on-board "ICE Chips" and require the MCU in the application board to
be socketed. Silicon Labs' debug paradigm increases ease of use and preserves the performance of the
precision analog peripherals.
Silicon Labs Integrated
Development Environment
WINDOWS 2000 or later
Debug
Adapter
C2 (x2), VDD, GND
VDD
TARGET PCB
GND
C8051F360
Figure 1.7. Development/In-System Debug Diagram
1.4.
Programmable Digital I/O and Crossbar
C8051F36x devices include up to 39 I/O pins (four byte-wide Ports and one 7-bit-wide Port). The
C8051F36x Ports behave like typical 8051 Ports with a few enhancements. Each Port pin may be configured as an analog input or a digital I/O pin. Pins selected as digital I/Os may additionally be configured for
push-pull or open-drain output. The “weak pullups” that are fixed on typical 8051 devices may be globally
disabled, providing power savings capabilities.
26
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
The Digital Crossbar allows mapping of internal digital system resources to Port I/O pins. (See Figure 1.8.)
On-chip counter/timers, serial buses, HW interrupts, comparator output, and other digital signals in the
controller can be configured to appear on the Port I/O pins specified in the Crossbar Control registers. This
allows the user to select the exact mix of general purpose Port I/O and digital resources needed for the
particular application.
P0MASK, P0MATCH
P1MASK, P1MATCH,
P2MASK, P2MATCH
Registers
XBR0, XBR1,
PnSKIP Registers
Priority
Decoder
Highest
Priority
2
UART
8
4
SPI
(Internal Digital Signals)
PnMDOUT,
PnMDIN Registers
SMBus
CP0
CP1
Outputs
2
Digital
Crossbar
8
P0.0
P1
I/O
Cells
P1.0
P2
I/O
Cell
P2.0
P3
I/O
Cells
P3.0
8
7
8
2
T0, T1
P0.7
P1.7
4
SYSCLK
PCA
Lowest
Priority
P0
I/O
Cells
8
P0
(P0.0-P0.7)
P1
(P1.0-P1.7)
P2
(P2.0-P2.7)
P3
(P3.0-P3.7)
P2.7
3.1–3.4 available on
C8051F360/1/3/4/6/8
P3.7
3.5–3.7 available on
C8051F360/3
(Port Latches)
8
8
8
Figure 1.8. Digital Crossbar Diagram (Port 0 to Port 3)
1.5.
Serial Ports
The C8051F36x Family includes an SMBus/I2C interface, a full-duplex UART with enhanced baud rate
configuration, and an Enhanced SPI interface. Each of the serial buses is fully implemented in hardware
and makes extensive use of the CIP-51's interrupts, thus requiring very little CPU intervention.
1.6.
Programmable Counter Array
An on-chip Programmable Counter/Timer Array (PCA) is included in addition to the four 16-bit general purpose counter/timers. The PCA consists of a dedicated 16-bit counter/timer time base with three programmable capture/compare modules. The PCA clock is derived from one of six sources: the system clock
divided by 12, the system clock divided by 4, Timer 0 overflows, an External Clock Input (ECI), the system
clock, or the external oscillator clock source divided by 8. The external clock source selection is useful for
Rev. 1.2
27
C8051F360/1/2/3/4/5/6/7/8/9
real-time clock functionality, where the PCA is clocked by an external source while the internal oscillator
drives the system clock.
Each capture/compare module can be configured to operate in one of six modes: Edge-Triggered Capture,
Software Timer, High Speed Output, 8- or 16-bit Pulse Width Modulator, or Frequency Output. Additionally,
Capture/Compare Module 5 offers watchdog timer (WDT) capabilities. Following a system reset, Module 5
is configured and enabled in WDT mode. The PCA Capture/Compare Module I/O and External Clock Input
may be routed to Port I/O via the Digital Crossbar.
SYSCLK/12
SYSCLK/4
Timer 0 Overflow
ECI
SYSCLK
PCA
CLOCK
MUX
16-Bit Counter/Timer
External Clock/8
Capture/Compare
Module 0
Capture/Compare
Module 1
Capture/Compare
Module 2
Capture/Compare
Module 3
Capture/Compare
Module 4
Capture/Compare
Module 5
CEX5
CEX4
CEX3
CEX2
CEX1
CEX0
ECI
Crossbar
Port I/O
Figure 1.10. PCA Block Diagram
1.7.
10-Bit Analog to Digital Converter
The C8051F360/1/2/6/7/8/9 devices include an on-chip 10-bit SAR ADC with up to 21 channels for the differential input multiplexer. With a maximum throughput of 200 ksps, the ADC offers true 10-bit linearity with
an INL and DNL of ±1 LSB. The ADC system includes a configurable analog multiplexer that selects both
positive and negative ADC inputs. Ports1-3 are available as an ADC inputs; additionally, the on-chip Temperature Sensor output and the power supply voltage (VDD) are available as ADC inputs. User firmware
may shut down the ADC to save power.
Conversions can be started in six ways: a software command, an overflow of Timer 0, 1, 2, or 3, or an
external convert start signal (CNVSTR). This flexibility allows the start of conversion to be triggered by software events, a periodic signal (timer overflows), or external HW signals. Conversion completions are indi-
28
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
cated by a status bit and an interrupt (if enabled). The resulting 10-bit data word is latched into the ADC
data SFRs upon completion of a conversion.
Window compare registers for the ADC data can be configured to interrupt the controller when ADC data is
either within or outside of a specified range. The ADC can monitor a key voltage continuously in background mode, but not interrupt the controller unless the converted data is within/outside the specified
range.
P1.0
AD0CM0
AD0CM1
P3.4
ADC
AD0SC0
AD0LJST
AD0SC1
AD0SC2
AD0SC3
AMX0N0
AMX0N1
AMX0N2
AMX0N3
AMX0N
AMX0N4
P3.4
23-to-1
AMUX
AD0SC4
P1.7
P2.0
P2.7
P3.0
ADC0L
(-)
ADC0CF
AD0BUSY (W)
001
Timer 0 Overflow
010
Timer 2 Overflow
011
100
Timer 1 Overflow
CNVSTR Input
101
Timer 3 Overflow
ADC0H
10-Bit
SAR
SYSCLK
P1.0
(+)
000
REF
Temp
Sensor
P3.1-3.4 available on
C8051F360/1/6/8
AD0CM2
Start
Conversion
VDD
P1.0-1.3 available on
C8051F361/2/6/7/8/9
AD0WINT
AD0INT
VDD
P2.7
P3.0
P3.1-3.4 available on
C8051F360/1/6/8
AD0BUSY
AD0EN
23-to-1
AMUX
AD0TM
AMX0P0
ADC0CN
AMX0P1
AMX0P2
P1.7
P2.0
AMX0P3
AMX0P
AMX0P4
P1.0-1.3 available on
C8051F361/2/6/7/8/9
ADC0LTH
AD0WINT
ADC0LTL
32
Window
Compare
Logic
ADC0GTH ADC0GTL
VREF
GND
Figure 1.11. 10-Bit ADC Block Diagram
1.8.
Comparators
C8051F36x devices include two on-chip voltage comparators that are enabled/disabled and configured via
user software. Port I/O pins may be configured as comparator inputs via a selection mux. Two comparator
outputs may be routed to a Port pin if desired: a latched output and/or an unlatched (asynchronous) output.
Comparator response time is programmable, allowing the user to select between high-speed and lowpower modes. Positive and negative hysteresis are also configurable.
Comparator interrupts may be generated on rising, falling, or both edges. When in IDLE mode, these interrupts may be used as a “wake-up” source. Comparator0 may also be configured as a reset source.
Figure 1.12 shows the Comparator0 block diagram, and Figure 1.13 shows the Comparator1 block diagram.
Note: The first Port I/O pins shown in Figure 1.12 and Figure 1.13 are for the 48-pin (C8051F360/3)
devices. The second set of Port I/O pins are for the 32-pin and 28-pin (C8051F361/2/4/5/6/7/8/9) devices.
Please refer to the CPTnMX registers (SFR Definition 8.2 and SFR Definition 8.5) for more information.
Rev. 1.2
29
CPT0CN
CPT0MX
C8051F360/1/2/3/4/5/6/7/8/9
CMX0N3
CMX0N2
CMX0N1
CMX0N0
CP0EN
CP0OUT
CP0RIF
CP0FIF
CP0HYP1
VDD
CP0HYP0
CP0HYN1
CP0HYN0
CMX0P1
CMX0P0
P1.4 / P1.0
P2.3 / P1.4
CP0 +
CP0
+
P3.1 / P2.0
D
-
P3.5 / P2.4
SET
CLR
D
Q
Q
SET
CLR
Q
Q
Crossbar
(SYNCHRONIZER)
GND
P1.5 / P1.1
P2.4 / P1.5
CP0A
Reset
Decision
Tree
CP0 -
CP0RIF
P3.2 / P2.1
CP0FIF
CPT0MD
P3.6 / P2.5
0
0
0
1
1
1
CP0RIE
CP0FIE
Figure 1.12. Comparator0 Block Diagram
Rev. 1.2
EA
0
CP0MD1
CP0MD0
30
CP0EN
1
CP0
Interrupt
CPT1CN
CPT1MX
C8051F360/1/2/3/4/5/6/7/8/9
CMX1N1
CMX1N0
CP1EN
CP1OUT
CP1RIF
CP1FIF
CP1HYP1
VDD
CP1HYP0
CP1HYN1
CP1HYN0
CMX1P1
CMX1P0
P2.0 / P1.2
P2.5 / P1.6
CP1 +
CP1
+
P3.3 / P2.2
D
-
P3.7 / P2.6
SET
CLR
D
Q
Q
SET
CLR
Q
Q
Crossbar
(SYNCHRONIZER)
GND
CP1A
P2.1 / P1.3
P2.6 / P1.7
CP1 -
CP1RIF
P3.4 / P2.3
CP1FIF
CPT1MD
P4.0 / P2.7
0
CP1EN
EA
1
0
0
0
1
1
CP1
Interrupt
1
CP1RIE
CP1FIE
CP1MD1
CP1MD0
Figure 1.13. Comparator1 Block Diagram
1.9.
10-bit Current Output DAC
The C8051F360/1/2/6/7/8/9 devices includes a 10-bit current-mode Digital-to-Analog Converter (IDA0).
The maximum current output of the IDA0 can be adjusted for three different current settings; 0.5 mA,
1 mA, and 2 mA. IDA0 features a flexible output update mechanism which allows for seamless full-scale
changes and supports jitter-free updates for waveform generation. Three update modes are provided,
allowing IDA0 output updates on a write to IDA0H, on a Timer overflow, or on an external pin edge.
Rev. 1.2
31
IDA0CN
CNVSTR
Timer 3
Timer 2
Timer 1
IDA0EN
IDA0CM2
IDA0CM1
IDA0CM0
Timer 0
IDA0H
C8051F360/1/2/3/4/5/6/7/8/9
IDA0H
8
IDA0L
IDA0OMD1
IDA0OMD0
2
10
Latch
IDA0
Figure 1.14. IDA0 Functional Block Diagram
32
Rev. 1.2
IDA0
C8051F360/1/2/3/4/5/6/7/8/9
2.
Absolute Maximum Ratings
Table 2.1. Absolute Maximum Ratings
Parameter
Conditions
Min
Typ
Max
Units
Ambient temperature under bias
–55
—
125
°C
Storage Temperature
–65
—
150
°C
Voltage on any Port I/O Pin or RST with
respect to GND
–0.3
—
5.8
V
Voltage on VDD with respect to GND
–0.3
—
4.2
V
Maximum Total current through VDD or GND
—
—
500
mA
Maximum output current sunk by RST or any
Port pin
—
—
100
mA
Note: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the devices at those or any other conditions above
those indicated in the operation listings of this specification is not implied. Exposure to maximum rating
conditions for extended periods may affect device reliability.
Rev. 1.2
33
C8051F360/1/2/3/4/5/6/7/8/9
3.
Global Electrical Characteristics
Table 3.1. Global Electrical Characteristics
–40 to +85 °C, 25 MHz system clock unless otherwise specified.
Parameter
Digital Supply Voltage
Conditions
SYSCLK = 0 to 50 MHz
SYSCLK > 50 MHz
Digital Supply RAM Data
Retention Voltage
SYSCLK (System Clock)1,2
C8051F360/1/2/3/4/5
C8051F366/7/8/9
Specified Operating
Temperature Range
Min
Typ
Max
Units
2.7
3.0
3.0
3.3
3.6
3.6
V
—
1.5
—
V
0
0
—
—
100
50
MHz
MHz
–40
—
+85
°C
Digital Supply Current—CPU Active (Normal Mode, fetching instructions from Flash)
IDD2
IDD Supply Sensitivity3
VDD = 3.6 V, F = 100 MHz
—
68
75
mA
VDD = 3.6 V, F = 25 MHz
—
21
25
mA
VDD = 3.0 V, F = 100 MHz
—
54
60
mA
VDD = 3.0 V, F = 25 MHz
—
16
18
mA
VDD = 3.0 V, F = 1 MHz
—
0.48
—
mA
VDD = 3.0 V, F = 80 kHz
—
36
—
µA
F = 25 MHz
—
56
—
%/V
F = 1 MHz
—
57
—
%/V
—
0.45
—
mA/MHz
VDD = 3.0 V, F > 20 MHz, T = 25 °C
—
0.38
—
mA/MHz
VDD = 3.6 V, F 20 MHz, T = 25 °C
—
0.51
—
mA/MHz
IDD Frequency Sensitivity3,4 VDD = 3.0 V, F 20 MHz, the estimate should
be the current at 25 MHz minus the difference in current indicated by the frequency sensitivity number. For
example: VDD = 3.0 V; F = 20 MHz, IDD = 15.9 mA - (25 MHz - 20 MHz) * 0.38 mA/MHz = 14 mA.
5. Idle IDD can be estimated for frequencies < 1 MHz by simply multiplying the frequency of interest by the
frequency sensitivity number for that range. When using these numbers to estimate Idle IDD for >1 MHz, the
estimate should be the current at 25 MHz minus the difference in current indicated by the frequency sensitivity
number. For example: VDD = 3.0 V; F = 5 MHz, Idle IDD = 7.2 mA - (25 MHz - 5 MHz) * 0.25 mA/MHz = 2.2 mA.
Other electrical characteristics tables are found in the data sheet section corresponding to the associated
peripherals. For more information on electrical characteristics for a specific peripheral, refer to the page
indicated in Table 3.2.
Rev. 1.2
35
C8051F360/1/2/3/4/5/6/7/8/9
Table 3.2. Index to Electrical Characteristics Tables
Peripheral Electrical Characteristics
Page No.
ADC0 Electrical Characteristics
63
IDAC Electrical Characteristics
67
Voltage Reference Electrical Characteristics
70
Comparator Electrical Characteristics
80
Reset Electrical Characteristics
135
Flash Electrical Characteristics
145
Internal High Frequency Oscillator Electrical Characteristics
172
Internal Low Frequency Oscillator Electrical Characteristics
173
PLL Frequency Characteristics
183
Port I/O DC Electrical Characteristics
202
36
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
4.
Pinout and Package Definitions
Table 4.1. Pin Definitions for the C8051F36x
Name
VDD
Pin
Pin
Pin
‘F360/3 ‘F361/4/6/8 ‘F362/5/7/9
(48-pin) (32-pin)
(28-pin)
Type
Description
19, 31, 43
4
4
Power Supply Voltage.
GND 18, 30, 42
3
3
Ground.
AGND
6
—
—
Analog Ground.
AV+
7
—
—
Analog Supply Voltage. Must be tied to +2.7 to
+3.6 V.
RST/
8
5
5
C2CK
P4.6/
D I/O Clock signal for the C2 Debug Interface.
9
—
—
C2D
P3.0/
D I/O Device Reset. Open-drain output of internal POR or
VDD Monitor. An external source can initiate a system
reset by driving this pin low for at least 10 µs.
D I/O or Port 4.6. See Section 17 for a complete description.
A In
D I/O Bi-directional data signal for the C2 Debug Interface.
—
6
6
C2D
D I/O or Port 3.0. See Section 17 for a complete description.
A In
D I/O Bi-directional data signal for the C2 Debug Interface.
P0.0
5
2
2
D I/O or Port 0.0. See Section 17 for a complete description.
A In
P0.1
4
1
1
D I/O or Port 0.1. See Section 17 for a complete description.
A In
P0.2
3
32
28
D I/O or Port 0.2. See Section 17 for a complete description.
A In
P0.3
2
31
27
D I/O or Port 0.3. See Section 17 for a complete description.
A In
P0.4
1
30
26
D I/O or Port 0.4. See Section 17 for a complete description.
A In
P0.5
48
29
25
D I/O or Port 0.5. See Section 17 for a complete description.
A In
P0.6
47
28
24
D I/O or Port 0.6. See Section 17 for a complete description.
A In
P0.7
46
27
23
D I/O or Port 0.7. See Section 17 for a complete description.
A In
Rev. 1.2
37
C8051F360/1/2/3/4/5/6/7/8/9
Table 4.1. Pin Definitions for the C8051F36x (Continued)
Name
Pin
Pin
Pin
‘F360/3 ‘F361/4/6/8 ‘F362/5/7/9
(48-pin) (32-pin)
(28-pin)
Type
Description
P1.0
45
26
22
D I/O or Port 1.0. See Section 17 for a complete description.
A In
P1.1
44
25
21
D I/O or Port 1.1. See Section 17 for a complete description.
A In
P1.2
41
24
20
D I/O or Port 1.2. See Section 17 for a complete description.
A In
P1.3
40
23
19
D I/O or Port 1.3. See Section 17 for a complete description.
A In
P1.4
39
22
18
D I/O or Port 1.4. See Section 17 for a complete description.
A In
P1.5
38
21
17
D I/O or Port 1.5. See Section 17 for a complete description.
A In
P1.6
37
20
16
D I/O or Port 1.6. See Section 17 for a complete description.
A In
P1.7
36
19
15
D I/O or Port 1.7. See Section 17 for a complete description.
A In
P2.0
35
18
14
D I/O or Port 2.0. See Section 17 for a complete description.
A In
P2.1
34
17
13
D I/O or Port 2.1. See Section 17 for a complete description.
A In
P2.2
33
16
12
D I/O or Port 2.2. See Section 17 for a complete description.
A In
P2.3
32
15
11
D I/O or Port 2.3. See Section 17 for a complete description.
A In
P2.4
29
14
10
D I/O or Port 2.4. See Section 17 for a complete description.
A In
P2.5
28
13
9
D I/O or Port 2.5. See Section 17 for a complete description.
A In
P2.6
27
12
8
D I/O or Port 2.6. See Section 17 for a complete description.
A In
P2.7
26
11
7
D I/O or Port 2.7. See Section 17 for a complete description.
A In
P3.0
25
—
—
D I/O or Port 3.0. See Section 17 for a complete description.
A In
38
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Table 4.1. Pin Definitions for the C8051F36x (Continued)
Name
Pin
Pin
Pin
‘F360/3 ‘F361/4/6/8 ‘F362/5/7/9
(48-pin) (32-pin)
(28-pin)
Type
Description
P3.1
24
7
—
D I/O or Port 3.1. See Section 17 for a complete description.
A In
P3.2
23
8
—
D I/O or Port 3.2. See Section 17 for a complete description.
A In
P3.3
22
9
—
D I/O or Port 3.3. See Section 17 for a complete description.
A In
P3.4
21
10
—
D I/O or Port 3.4. See Section 17 for a complete description.
A In
P3.5
20
—
—
D I/O or Port 3.5. See Section 17 for a complete description.
A In
P3.6
17
—
—
D I/O or Port 3.6. See Section 17 for a complete description.
A In
P3.7
16
—
—
D I/O or Port 3.7. See Section 17 for a complete description.
A In
P4.0
15
—
—
D I/O or Port 4.0. See Section 17 for a complete description.
A In
P4.1
14
—
—
D I/O Port 4.1. See Section 17 for a complete description.
P4.2
13
—
—
D I/O Port 4.2. See Section 17 for a complete description.
P4.3
12
—
—
D I/O Port 4.3. See Section 17 for a complete description.
P4.4
11
—
—
D I/O Port 4.4. See Section 17 for a complete description.
P4.5
10
—
—
D I/O Port 4.5. See Section 17 for a complete description.
Rev. 1.2
39
P0.5
P0.6
P0.7
P1.0
P1.1
VDD
GND
P1.2
P1.3
P1.4
P1.5
P1.6
48
47
46
45
44
43
42
41
40
39
38
37
C8051F360/1/2/3/4/5/6/7/8/9
P0.4
1
36
P1.7
P0.3
2
35
P2.0
P0.2
3
34
P2.1
P0.1
4
33
P2.2
P0.0
5
32
P2.3
AGND
6
31
VDD
AV+
7
30
GND
/RST/C2CK
8
29
P2.4
P4.6/C2D
9
28
P2.5
P4.5
10
27
P2.6
P4.4
11
26
P2.7
P4.3
12
25
P3.0
20
21
22
23
24
P3.5
P3.4
P3.3
P3.2
P3.1
17
P3.6
19
16
P3.7
VDD
15
P4.0
18
14
P4.1
GND
13
P4.2
C8051F360/3
Figure 4.1. TQFP-48 Pinout Diagram (Top View)
40
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Figure 4.2. TQFP-48 Package Diagram
Table 4.2. TQFP-48 Package Dimensions
Dimension
Min
Nom
Max
Dimension
A
A1
A2
b
c
D
D1
e
—
0.05
0.95
0.17
0.09
—
—
1.00
0.22
—
9.00 BSC.
7.00 BSC.
0.50 BSC.
1.20
0.15
1.05
0.27
0.20
E
E1
L
aaa
bbb
ccc
ddd
Min
0.45
0°
Nom
9.00 BSC.
7.00 BSC.
0.60
0.20
0.20
0.08
0.08
3.5°
Max
0.75
7°
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to JEDEC outline MS-026, variation ABC.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020C specification for Small Body
Components.
Rev. 1.2
41
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
P1.0
P1.1
32
31
30
29
28
27
26
25
C8051F360/1/2/3/4/5/6/7/8/9
P0.1
1
24
P1.2
P0.0
2
23
P1.3
GND
3
22
P1.4
VDD
4
21
P1.5
/RST/C2CK
5
20
P1.6
P3.0/C2D
6
19
P1.7
P3.1
7
18
P2.0
P3.2
8
17
P2.1
9
10
11
12
13
14
15
16
P3.3
P3.4
P2.7
P2.6
P2.5
P2.4
P2.3
P2.2
C8051F361/4/6/8
Figure 4.3. LQFP-32 Pinout Diagram (Top View)
42
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Figure 4.4. LQFP-32 Package Diagram
Table 4.3. LQFP-32 Package Dimensions
Dimension
Min
Nom
Max
Dimension
A
A1
A2
b
c
D
D1
e
—
0.05
1.35
0.30
0.09
—
—
1.40
0.37
—
9.00 BSC.
7.00 BSC.
0.80 BSC.
1.60
0.15
1.45
0.45
0.20
E
E1
L
aaa
bbb
ccc
ddd
Min
0.45
0°
Nom
9.00 BSC.
7.00 BSC.
0.60
0.20
0.20
0.10
0.20
3.5°
Max
0.75
7°
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to JEDEC outline MS-026, variation BBA.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020B specification for Small Body
Components.
Rev. 1.2
43
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
P1.0
28
27
26
25
24
23
22
C8051F360/1/2/3/4/5/6/7/8/9
P0.1
1
21
P1.1
P0.0
2
20
P1.2
GND
3
19
P1.3
VDD
4
18
P1.4
/RST/C2CK
5
17
P1.5
P3.0/C2D
6
16
P1.6
15
P1.7
C8051F362/5/7/9
GND
8
9
10
11
12
13
14
P2.5
P2.4
P2.3
P2.2
P2.1
P2.0
7
P2.6
P2.7
Figure 4.5. QFN-28 Pinout Diagram (Top View)
44
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Figure 4.6. QFN-28 Package Drawing
Table 4.4. QFN-28 Package Dimensions
Dimension
Min
Nom
Max
Dimension
Min
Nom
Max
A
A1
A3
b
D
D2
e
E
0.80
0.03
0.90
0.07
0.25 REF
0.25
5.00 BSC.
3.15
0.50 BSC.
5.00 BSC.
1.00
0.11
E2
L
aaa
bbb
ddd
eee
Z
Y
2.90
0.45
3.15
0.55
0.15
0.10
0.05
0.08
0.435
0.18
3.35
0.65
0.18
2.90
0.30
3.35
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to JEDEC outline MO-243, variation VHHD except for custom features D2,
E2, L, Z, and Y which are toleranced per supplier designation.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020C specification for Small Body
Components.
Rev. 1.2
45
C8051F360/1/2/3/4/5/6/7/8/9
Figure 4.7. Typical QFN-28 Landing Diagram
46
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Figure 4.8. QFN-28 Solder Paste Recommendation
Rev. 1.2
47
C8051F360/1/2/3/4/5/6/7/8/9
5.
10-Bit ADC (ADC0, C8051F360/1/2/6/7/8/9)
The ADC0 subsystem for the C8051F360/1/2/6/7/8/9 consists of two analog multiplexers (referred to collectively as AMUX0) with 23 total input selections, and a 200 ksps, 10-bit successive-approximation-register ADC with integrated track-and-hold and programmable window detector. The AMUX0, data conversion
modes, and window detector are all configurable under software control via the Special Function Registers
shown in Figure 5.1. ADC0 operates in both Single-ended and Differential modes, and may be configured
to measure P1.0-P3.4 (where available), the Temperature Sensor output, or VDD with respect to P1.0P3.4, VREF, or GND. The ADC0 subsystem is enabled only when the AD0EN bit in the ADC0 Control register (ADC0CN) is set to logic ‘1’. The ADC0 subsystem is in low power shutdown when this bit is logic ‘0’.
P1.0
ADC
AD0SC0
AD0LJST
AD0SC1
AD0SC2
AD0SC3
AMX0N0
AMX0N1
AMX0N2
AMX0N
AMX0N3
P3.4
23-to-1
AMUX
AMX0N4
P2.7
P3.0
AD0SC4
P1.7
P2.0
ADC0CF
ADC0LTH
AD0CM0
ADC0LTL
ADC0GTH ADC0GTL
GND
Figure 5.1. ADC0 Functional Block Diagram
Rev. 1.2
Timer 0 Overflow
010
Timer 2 Overflow
011
100
Timer 1 Overflow
CNVSTR Input
101
Timer 3 Overflow
AD0WINT
VREF
48
AD0BUSY (W)
001
ADC0H
(-)
000
REF
10-Bit
SAR
SYSCLK
P1.0
(+)
ADC0L
VDD
P3.1-3.4 available on
C8051F360/1/6/8
AD0CM1
Start
Conversion
P3.4
Temp
Sensor
P1.0-1.3 available on
C8051F361/2/6/7/8/9
AD0CM2
AD0WINT
AD0INT
VDD
P2.7
P3.0
P3.1-3.4 available on
C8051F360/1/6/8
AD0BUSY
AD0EN
23-to-1
AMUX
AD0TM
AMX0P0
ADC0CN
AMX0P1
AMX0P2
P1.7
P2.0
AMX0P3
AMX0P
AMX0P4
P1.0-1.3 available on
C8051F361/2/6/7/8/9
32
Window
Compare
Logic
C8051F360/1/2/3/4/5/6/7/8/9
5.1.
Analog Multiplexer
AMUX0 selects the positive and negative inputs to the ADC. Any of the following may be selected as the
positive input: the AMUX0 Port I/O inputs, the on-chip temperature sensor, or the positive power supply
(VDD). Any of the following may be selected as the negative input: the AMUX0 Port I/O inputs, VREF, or
GND. When GND is selected as the negative input, ADC0 operates in Single-ended Mode; all other
times, ADC0 operates in Differential Mode. The ADC0 input channels are selected in the AMX0P and
AMX0N registers as described in SFR Definition 5.1 and SFR Definition 5.2.
The conversion code format differs between Single-ended and Differential modes. The registers ADC0H
and ADC0L contain the high and low bytes of the output conversion code from the ADC at the completion
of each conversion. Data can be right-justified or left-justified, depending on the setting of the AD0LJST bit
(ADC0CN.0). When in Single-ended Mode, conversion codes are represented as 10-bit unsigned integers.
Inputs are measured from ‘0’ to VREF * 1023/1024. Example codes are shown below for both right-justified
and left-justified data. Unused bits in the ADC0H and ADC0L registers are set to ‘0’.
Input Voltage
VREF x 1023/1024
VREF x 512/1024
VREF x 256/1024
0
Right-Justified ADC0H:ADC0L
(AD0LJST = 0)
0x03FF
0x0200
0x0100
0x0000
Left-Justified ADC0H:ADC0L
(AD0LJST = 1)
0xFFC0
0x8000
0x4000
0x0000
When in Differential Mode, conversion codes are represented as 10-bit signed 2’s complement numbers.
Inputs are measured from -VREF to VREF * 511/512. Example codes are shown below for both right-justified and left-justified data. For right-justified data, the unused MSBs of ADC0H are a sign-extension of the
data word. For left-justified data, the unused LSBs in the ADC0L register are set to ‘0’.
Input Voltage
VREF x 511/512
VREF x 256/512
0
–VREF x 256/512
–VREF
Right-Justified ADC0H:ADC0L
(AD0LJST = 0)
0x01FF
0x0100
0x0000
0xFF00
0xFE00
Left-Justified ADC0H:ADC0L
(AD0LJST = 1)
0x7FC0
0x4000
0x0000
0xC000
0x8000
Important Note About ADC0 Input Configuration: Port pins selected as ADC0 inputs should be configured as analog inputs, and should be skipped by the Digital Crossbar. To configure a Port pin for analog
input, set to ‘0’ the corresponding bit in register PnMDIN (for n = 0,1,2,3). To force the Crossbar to skip a
Port pin, set to ‘1’ the corresponding bit in register PnSKIP (for n = 0,1,2,3). See Section “17. Port Input/
Output” on page 184 for more Port I/O configuration details.
Rev. 1.2
49
C8051F360/1/2/3/4/5/6/7/8/9
5.2.
Temperature Sensor
The typical temperature sensor transfer function is shown in Figure 5.2. The output voltage (VTEMP) is the
positive ADC input when the temperature sensor is selected by bits AMX0P4-0 in register AMX0P.
(mV)
1200
1100
1000
900
V TEMP = Slope*(TEMP C) + Offset mV
800
700
-50
0
50
100
(Celsius)
Figure 5.2. Typical Temperature Sensor Transfer Function
The uncalibrated temperature sensor output is extremely linear and suitable for relative temperature measurements (see Table 5.1 for linearity specifications). For absolute temperature measurements, gain and/
or offset calibration is recommended. Typically a 1-point calibration includes the following steps:
Step 1. Control/measure the ambient temperature (this temperature must be known).
Step 2. Power the device, and delay for a few seconds to allow for self-heating.
Step 3. Perform an ADC conversion with the temperature sensor selected as the positive input
and GND selected as the negative input.
Step 4. Calculate the offset and/or gain characteristics, and store these values in non-volatile
memory for use with subsequent temperature sensor measurements.
Figure 5.3 shows the typical temperature sensor error assuming a 1-point calibration at 25 °C. Note that
parameters which affect ADC measurement, in particular the voltage reference value, will also
affect temperature measurement.
50
Rev. 1.2
Error (degrees C)
C8051F360/1/2/3/4/5/6/7/8/9
5.00
5.00
4.00
4.00
3.00
3.00
2.00
2.00
1.00
1.00
0.00
-40.00
-20.00
0.00
40.00
20.00
60.00
80.00
0.00
-1.00
-1.00
-2.00
-2.00
-3.00
-3.00
-4.00
-4.00
-5.00
-5.00
Temperature (degrees C)
Figure 5.3. Temperature Sensor Error with 1-Point Calibration
Rev. 1.2
51
C8051F360/1/2/3/4/5/6/7/8/9
5.3.
Modes of Operation
ADC0 has a maximum conversion speed of 200 ksps. The ADC0 conversion clock is a divided version of
the system clock, determined by the AD0SC bits in the ADC0CF register (system clock divided by
(AD0SC + 1) for 0 AD0SC 31).
5.3.1. Starting a Conversion
A conversion can be initiated in one of five ways, depending on the programmed states of the ADC0 Start
of Conversion Mode bits (AD0CM2-0) in register ADC0CN. Conversions may be initiated by one of the following:
1.
2.
3.
4.
5.
6.
Writing a ‘1’ to the AD0BUSY bit of register ADC0CN
A Timer 0 overflow (i.e., timed continuous conversions)
A Timer 2 overflow
A Timer 1 overflow
A rising edge on the CNVSTR input signal
A Timer 3 overflow
Writing a ‘1’ to AD0BUSY provides software control of ADC0 whereby conversions are performed "ondemand". During conversion, the AD0BUSY bit is set to logic ‘1’ and reset to logic ‘0’ when the conversion
is complete. The falling edge of AD0BUSY triggers an interrupt (when enabled) and sets the ADC0 interrupt flag (AD0INT). Note: When polling for ADC conversion completions, the ADC0 interrupt flag (AD0INT)
should be used. Converted data is available in the ADC0 data registers, ADC0H:ADC0L, when bit AD0INT
is logic ‘1’. Note that when Timer 2 or Timer 3 overflows are used as the conversion source, Low Byte overflows are used if Timer 2/3 is in 8-bit mode; High byte overflows are used if Timer 2/3 is in 16-bit mode. See
Section “21. Timers” on page 248 for timer configuration.
Important Note About Using CNVSTR: The CNVSTR input pin also functions as Port pin P0.7 on the
C8051F360 devices and Port pin P0.6 on the C8051F361/2/6/7/8/9 devices. When the CNVSTR input is
used as the ADC0 conversion source, the corresponding port pin should be skipped by the Digital Crossbar. To configure the Crossbar to skip the port pin, set the appropriate bit to ‘1’ in register P0SKIP. See
Section “17. Port Input/Output” on page 184 for details on Port I/O configuration.
52
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
5.3.2. Tracking Modes
According to Table 5.1, each ADC0 conversion must be preceded by a minimum tracking time for the converted result to be accurate. The AD0TM bit in register ADC0CN controls the ADC0 track-and-hold mode.
In its default state, the ADC0 input is continuously tracked, except when a conversion is in progress. When
the AD0TM bit is logic ‘1’, ADC0 operates in low-power track-and-hold mode. In this mode, each conversion is preceded by a tracking period of 3 SAR clocks (after the start-of-conversion signal). When the
CNVSTR signal is used to initiate conversions in low-power tracking mode, ADC0 tracks only when
CNVSTR is low; conversion begins on the rising edge of CNVSTR (see Figure 5.4). Tracking can also be
disabled (shutdown) when the device is in low power standby or sleep modes. Low-power track-and-hold
mode is also useful when AMUX settings are frequently changed, due to the settling time requirements
described in Section “5.3.3. Settling Time Requirements” on page 54.
A. ADC0 Timing for External Trigger Source
CNVSTR
(AD0CM[2:0]=100)
1
2
3
4
5
6
7
8
9
10 11
SAR Clocks
AD0TM=1
AD0TM=0
Write '1' to AD0BUSY,
Timer 0, Timer 2,
Timer 1, Timer 3 Overflow
(AD0CM[2:0]=000, 001,010
011, 101)
Low Power
or Convert
Track
Track or Convert
Convert
Low Power
Mode
Convert
Track
B. ADC0 Timing for Internal Trigger Source
1
2
3
4
5
6
7
8
9
10 11 12 13 14
SAR Clocks
AD0TM=1
Low Power
or Convert
Track
1
2
3
Convert
4
5
6
7
8
9
Low Power Mode
10 11
SAR Clocks
AD0TM=0
Track or
Convert
Convert
Track
Figure 5.4. 10-Bit ADC Track and Conversion Example Timing
Rev. 1.2
53
C8051F360/1/2/3/4/5/6/7/8/9
5.3.3. Settling Time Requirements
When the ADC0 input configuration is changed (i.e., a different AMUX0 selection is made), a minimum
tracking time is required before an accurate conversion can be performed. This tracking time is determined
by the AMUX0 resistance, the ADC0 sampling capacitance, any external source resistance, and the accuracy required for the conversion. In low-power tracking mode, three SAR clocks are used for tracking at the
start of every conversion. For most applications, these three SAR clocks will meet the minimum tracking
time requirements.
Figure 5.5 shows the equivalent ADC0 input circuits for both Differential and Single-ended modes. Notice
that the equivalent time constant for both input circuits is the same. The required ADC0 settling time for a
given settling accuracy (SA) may be approximated by Equation 5.1. When measuring the Temperature
Sensor output or VDD with respect to GND, RTOTAL reduces to RMUX. See Table 5.1 for ADC0 minimum
settling time requirements.
Equation 5.1. ADC0 Settling Time Requirements
n
2
t = ln ------- R TOTAL C SAMPLE
SA
Where:
SA is the settling accuracy, given as a fraction of an LSB (for example, 0.25 to settle within 1/4 LSB)
t is the required settling time in seconds
RTOTAL is the sum of the AMUX0 resistance and any external source resistance.
n is the ADC resolution in bits (10).
Differential Mode
Single-Ended Mode
MUX Select
MUX Select
Px.x
Px.x
RMUX = 5k
RMUX = 5k
CSAMPLE = 5pF
CSAMPLE = 5pF
RCInput= RMUX * CSAMPLE
RCInput= RMUX * CSAMPLE
CSAMPLE = 5pF
Px.x
RMUX = 5k
MUX Select
Figure 5.5. ADC0 Equivalent Input Circuits
54
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 5.1. AMX0P: AMUX0 Positive Channel Select
SFR Page:
all pages
SFR Address: 0xBB
R
R
R
R/W
R/W
R/W
R/W
–
–
–
AMX0P4
AMX0P3
AMX0P2
AMX0P1
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
AMX0P0 00000000
Bit0
Bits 7–5: UNUSED. Read = 000b; Write = don’t care.
Bits 4–0: AMX0P4–0: AMUX0 Positive Input Selection
AMX0P4-0
ADC0 Positive Input
(1)
P1.0(1)
00001(1)
P1.1(1)
00010(1)
P1.2(1)
00011(1)
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
P1.3(1)
P1.4
P1.5
P1.6
P1.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
P3.0
10001(2)
P3.1(2)
10010(2)
P3.2(2)
10011(2)
P3.3(2)
00000
(2)
P3.4(2)
RESERVED
Temp Sensor
VDD
10100
10101–11101
11110
11111
Notes:
1. Only applies to C8051F361/2/6/7/8/9 (32-pin and 28-pin); selection
RESERVED on C8051F360 (48-pin) device.
2. Only applies to C8051F360/1/6/8 (48-pin and 32-pin); selection RESERVED
on C8051F362/7/9 (28-pin) devices.
Rev. 1.2
55
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 5.2. AMX0N: AMUX0 Negative Channel Select
SFR Page:
all pages
SFR Address: 0xBA
R
R
R
R/W
R/W
R/W
R/W
–
–
–
AMX0N4
AMX0N3
AMX0N2
AMX0N1
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
AMX0N0 00000000
Bit0
Bits 7–5: UNUSED. Read = 000b; Write = don’t care.
Bits 4–0: AMX0N4–0: AMUX0 Negative Input Selection.
Note that when GND is selected as the Negative Input, ADC0 operates in Single-ended
mode. For all other Negative Input selections, ADC0 operates in Differential mode.
AMX0N4-0
ADC0 Negative Input
00000(1)
P1.0(1)
00001(1)
P1.1(1)
00010(1)
P1.2(1)
00011(1)
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
P1.3(1)
P1.4
P1.5
P1.6
P1.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
P3.0
10001(2)
P3.1(2)
10010(2)
P3.2(2)
10011(2)
P3.3(2)
10100(2)
10101–11101
11110
11111
P3.4(2)
RESERVED
VREF
GND
Notes:
1. Only applies to C8051F361/2/6/7/8/9 (32-pin and 28-pin); selection
RESERVED on C8051F360 (48-pin) device.
2. Only applies to C8051F360/1/6/8 (48-pin and 32-pin); selection RESERVED
on C8051F362/7/9 (28-pin) devices.
56
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 5.3. ADC0CF: ADC0 Configuration
SFR Page:
all pages
SFR Address: 0xBC
R/W
R/W
R/W
R/W
AD0SC4
AD0SC3
AD0SC2
AD0SC1
Bit7
Bit6
Bit5
Bit4
R/W
R/W
AD0SC0 AD0LJST
Bit3
Bit2
R/W
R/W
Reset Value
–
–
11111000
Bit1
Bit0
Bits 7–3: AD0SC4–0: ADC0 SAR Conversion Clock Period Bits.
SAR Conversion clock is derived from system clock by the following equation, where
AD0SC refers to the 5-bit value held in bits AD0SC4–0. SAR Conversion clock requirements are given in Table 5.1.
SYSCLK
AD0SC = ---------------------- – 1
CLK SAR
Bit 2:
AD0LJST: ADC0 Left Justify Select.
0: Data in ADC0H:ADC0L registers are right-justified.
1: Data in ADC0H:ADC0L registers are left-justified.
Bits 1–0: UNUSED. Read = 00b; Write = don’t care.
SFR Definition 5.4. ADC0H: ADC0 Data Word MSB
SFR Page:
all pages
SFR Address: 0xBE
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: ADC0 Data Word High-Order Bits.
For AD0LJST = 0: Bits 7–2 are the sign extension of Bit1. Bits 1–0 are the upper 2 bits of the
10-bit ADC0 Data Word.
For AD0LJST = 1: Bits 7–0 are the most-significant bits of the 10-bit ADC0 Data Word.
SFR Definition 5.5. ADC0L: ADC0 Data Word LSB
SFR Page:
all pages
SFR Address: 0xBD
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: ADC0 Data Word Low-Order Bits.
For AD0LJST = 0: Bits 7–0 are the lower 8 bits of the 10-bit Data Word.
For AD0LJST = 1: Bits 7–6 are the lower 2 bits of the 10-bit Data Word. Bits 5–0 will always
read ‘0’.
Rev. 1.2
57
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 5.6. ADC0CN: ADC0 Control
SFR Page:
all pages
SFR Address: 0xE8
R/W
R/W
AD0EN
AD0TM
Bit7
Bit6
(bit addressable)
R/W
R/W
R/W
R/W
R/W
AD0INT AD0BUSY AD0WINT AD0CM2 AD0CM1
Bit5
Bit4
Bit3
Bit 7:
Bit2
Bit1
R/W
Reset Value
AD0CM0 00000000
Bit0
AD0EN: ADC0 Enable Bit.
0: ADC0 Disabled. ADC0 is in low-power shutdown.
1: ADC0 Enabled. ADC0 is active and ready for data conversions.
Bit 6:
AD0TM: ADC0 Track Mode Bit.
0: Normal Track Mode: When ADC0 is enabled, tracking is continuous unless a conversion is
in progress.
1: Low-power Track Mode: Tracking Defined by AD0CM2-0 bits (see below).
Bit 5:
AD0INT: ADC0 Conversion Complete Interrupt Flag.
0: ADC0 has not completed a data conversion since the last time AD0INT was cleared.
1: ADC0 has completed a data conversion.
Bit 4:
AD0BUSY: ADC0 Busy Bit.
Read:
0: ADC0 conversion is complete or a conversion is not currently in progress. AD0INT is set to
logic ‘1’ on the falling edge of AD0BUSY.
1: ADC0 conversion is in progress.
Write:
0: No Effect.
1: Initiates ADC0 Conversion if AD0CM2-0 = 000b
Bit 3:
AD0WINT: ADC0 Window Compare Interrupt Flag.
0: ADC0 Window Comparison Data match has not occurred since this flag was last cleared.
1: ADC0 Window Comparison Data match has occurred.
Bits 2–0: AD0CM2–0: ADC0 Start of Conversion Mode Select.
When AD0TM = 0:
000: ADC0 conversion initiated on every write of ‘1’ to AD0BUSY.
001: ADC0 conversion initiated on overflow of Timer 0.
010: ADC0 conversion initiated on overflow of Timer 2.
011: ADC0 conversion initiated on overflow of Timer 1.
100: ADC0 conversion initiated on rising edge of external CNVSTR.
101: ADC0 conversion initiated on overflow of Timer 3.
11x: Reserved.
When AD0TM = 1:
000: Tracking initiated on write of ‘1’ to AD0BUSY and lasts 3 SAR clocks, followed by conversion.
001: Tracking initiated on overflow of Timer 0 and lasts 3 SAR clocks, followed by conversion.
010: Tracking initiated on overflow of Timer 2 and lasts 3 SAR clocks, followed by conversion.
011: Tracking initiated on overflow of Timer 1 and lasts 3 SAR clocks, followed by conversion.
100: ADC0 tracks only when CNVSTR input is logic low; conversion starts on rising CNVSTR
edge.
101: Tracking initiated on overflow of Timer 3 and lasts 3 SAR clocks, followed by conversion.
11x: Reserved.
58
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
5.4.
Programmable Window Detector
The ADC Programmable Window Detector continuously compares the ADC0 output registers to user-programmed limits, and notifies the system when a desired condition is detected. This is especially effective in
an interrupt-driven system, saving code space and CPU bandwidth while delivering faster system
response times. The window detector interrupt flag (AD0WINT in register ADC0CN) can also be used in
polled mode. The ADC0 Greater-Than (ADC0GTH, ADC0GTL) and Less-Than (ADC0LTH, ADC0LTL)
registers hold the comparison values. The window detector flag can be programmed to indicate when measured data is inside or outside of the user-programmed limits, depending on the contents of the ADC0
Less-Than and ADC0 Greater-Than registers.
SFR Definition 5.7. ADC0GTH: ADC0 Greater-Than Data High Byte
SFR Page:
all pages
SFR Address: 0xC4
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: High byte of ADC0 Greater-Than Data Word.
SFR Definition 5.8. ADC0GTL: ADC0 Greater-Than Data Low Byte
SFR Page:
all pages
SFR Address: 0xC3
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: Low byte of ADC0 Greater-Than Data Word.
Rev. 1.2
59
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 5.9. ADC0LTH: ADC0 Less-Than Data High Byte
SFR Page:
all pages
SFR Address: 0xC6
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: High byte of ADC0 Less-Than Data Word.
SFR Definition 5.10. ADC0LTL: ADC0 Less-Than Data Low Byte
SFR Page:
all pages
SFR Address: 0xC5
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: Low byte of ADC0 Less-Than Data Word.
60
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
5.4.1. Window Detector In Single-Ended Mode
Figure 5.6 shows two example window comparisons for right-justified, single-ended data, with
ADC0LTH:ADC0LTL = 0x0080 (128d) and ADC0GTH:ADC0GTL = 0x0040 (64d). In single-ended mode,
the input voltage can range from ‘0’ to VREF x (1023/1024) with respect to GND, and is represented by a
10-bit unsigned integer value. In the left example, an AD0WINT interrupt will be generated if the ADC0
conversion word (ADC0H:ADC0L) is within the range defined by ADC0GTH:ADC0GTL and
ADC0LTH:ADC0LTL (if 0x0040 < ADC0H:ADC0L < 0x0080). In the right example, and AD0WINT interrupt
will be generated if the ADC0 conversion word is outside of the range defined by the ADC0GT and
ADC0LT registers (if ADC0H:ADC0L < 0x0040 or ADC0H:ADC0L > 0x0080). Figure 5.7 shows an example using left-justified data with the same comparison values.
ADC0H:ADC0L
ADC0H:ADC0L
Input Voltage
(Px.x - GND)
VREF x (1023/1024)
Input Voltage
(Px.x - GND)
VREF x (1023/1024)
0x03FF
0x03FF
AD0WINT
not affected
AD0WINT=1
0x0081
VREF x (128/1024)
0x0080
0x0081
ADC0LTH:ADC0LTL
VREF x (128/1024)
0x007F
0x0080
0x007F
AD0WINT=1
VREF x (64/1024)
0x0041
0x0040
ADC0GTH:ADC0GTL
VREF x (64/1024)
0x003F
0x0041
0x0040
ADC0GTH:ADC0GTL
AD0WINT
not affected
ADC0LTH:ADC0LTL
0x003F
AD0WINT=1
AD0WINT
not affected
0
0x0000
0
0x0000
Figure 5.6. ADC Window Compare Example: Right-Justified Single-Ended Data
ADC0H:ADC0L
ADC0H:ADC0L
Input Voltage
(Px.x - GND)
VREF x (1023/1024)
Input Voltage
(Px.x - GND)
VREF x (1023/1024)
0xFFC0
0xFFC0
AD0WINT
not affected
AD0WINT=1
0x2040
VREF x (128/1024)
0x2000
0x2040
ADC0LTH:ADC0LTL
VREF x (128/1024)
0x1FC0
0x2000
0x1FC0
AD0WINT=1
0x1040
VREF x (64/1024)
0x1000
0x1040
ADC0GTH:ADC0GTL
VREF x (64/1024)
0x0FC0
0x1000
0x0000
AD0WINT
not affected
ADC0LTH:ADC0LTL
0x0FC0
AD0WINT=1
AD0WINT
not affected
0
ADC0GTH:ADC0GTL
0
0x0000
Figure 5.7. ADC Window Compare Example: Left-Justified Single-Ended Data
Rev. 1.2
61
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5.4.2. Window Detector In Differential Mode
Figure 5.8 shows two example window comparisons for right-justified, differential data, with
ADC0LTH:ADC0LTL = 0x0040 (+64d) and ADC0GTH:ADC0GTH = 0xFFFF (-1d). In differential mode, the
measurable voltage between the input pins is between -VREF and VREF*(511/512). Output codes are represented as 10-bit 2’s complement signed integers. In the left example, an AD0WINT interrupt will be generated if the ADC0 conversion word (ADC0H:ADC0L) is within the range defined by ADC0GTH:ADC0GTL
and ADC0LTH:ADC0LTL (if 0xFFFF (-1d) < ADC0H:ADC0L < 0x0040 (64d)). In the right example, an
AD0WINT interrupt will be generated if the ADC0 conversion word is outside of the range defined by the
ADC0GT and ADC0LT registers (if ADC0H:ADC0L < 0xFFFF (-1d) or ADC0H:ADC0L > 0x0040 (+64d)).
Figure 5.9 shows an example using left-justified data with the same comparison values.
ADC0H:ADC0L
ADC0H:ADC0L
Input Voltage
(Px.x - Px.x)
VREF x (511/512)
Input Voltage
(Px.x - Px.x)
0x01FF
VREF x (511/512)
0x01FF
AD0WINT
not affected
AD0WINT=1
0x0041
VREF x (64/512)
0x0040
0x0041
ADC0LTH:ADC0LTL
VREF x (64/512)
0x003F
0x0040
0x003F
AD0WINT=1
0x0000
VREF x (-1/512)
0xFFFF
0x0000
ADC0GTH:ADC0GTL
VREF x (-1/512)
0xFFFE
0xFFFF
ADC0GTH:ADC0GTL
AD0WINT
not affected
ADC0LTH:ADC0LTL
0xFFFE
AD0WINT=1
AD0WINT
not affected
-VREF
0x0200
-VREF
0x0200
Figure 5.8. ADC Window Compare Example: Right-Justified Differential Data
ADC0H:ADC0L
ADC0H:ADC0L
Input Voltage
(Px.x - Px.x)
VREF x (511/512)
Input Voltage
(Px.x - Px.y)
0x7FC0
VREF x (511/512)
0x7FC0
AD0WINT
not affected
AD0WINT=1
0x1040
VREF x (64/512)
0x1000
0x1040
ADC0LTH:ADC0LTL
VREF x (64/512)
0x0FC0
0x1000
0x0FC0
AD0WINT=1
0x0000
VREF x (-1/512)
0xFFC0
0x0000
ADC0GTH:ADC0GTL
VREF x (-1/512)
0xFF80
0xFFC0
AD0WINT
not affected
ADC0LTH:ADC0LTL
0xFF80
AD0WINT=1
AD0WINT
not affected
-VREF
ADC0GTH:ADC0GTL
0x8000
-VREF
0x8000
Figure 5.9. ADC Window Compare Example: Left-Justified Differential Data
62
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Table 5.1. ADC0 Electrical Characteristics
VDD = 3.0 V, VREF = 2.40 V (REFSL=0), –40 to +85 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
DC Accuracy
Resolution
10
Integral Nonlinearity
Differential Nonlinearity
Guaranteed Monotonic
Offset Error
Full Scale Error
Differential mode
bits
—
±0.5
±1
LSB
—
±0.5
±1
LSB
–12
3
12
LSB
–5
1
5
LSB
Dynamic Performance (10 kHz sine-wave Single-ended input, 0 to 1 dB below Full Scale, 200 ksps)
Signal-to-Noise Plus Distortion
53
58
—
dB
—
–75
—
dB
—
75
—
dB
SAR Conversion Clock
—
—
3
MHz
Conversion Time in SAR Clocks
13
—
—
clocks
Track/Hold Acquisition Time
300
—
—
ns
—
—
200
ksps
Single Ended (AIN+ – GND)
Differential (AIN+ – AIN–)
0
–VREF
—
—
VREF
VREF
V
V
Single Ended or Differential
0
—
VDD
V
—
5
—
pF
Linearity*
—
±0.2
—
°C
Slope
—
2.18
—
mV/ºC
Slope Error*
—
±172
—
µV/ºC
—
802
—
mV
—
±18.5
—
mV
—
450
900
µA
—
3
—
mV/V
Total Harmonic Distortion
Up to the 5th harmonic
Spurious-Free Dynamic Range
Conversion Rate
Throughput Rate
Analog Inputs
ADC Input Voltage Range
Absolute Pin Voltage with
respect to GND
Input Capacitance
Temperature Sensor
Offset
(Temp = 0 °C)
Offset Error*
Power Specifications
Power Supply Current
(VDD supplied to ADC0)
Operating Mode, 200 ksps
Power Supply Rejection
*Note: Represents one standard deviation from the mean. Includes ADC offset, gain, and linearity variations.
Rev. 1.2
63
C8051F360/1/2/3/4/5/6/7/8/9
6. 10-Bit Current Mode DAC (IDA0, C8051F360/1/2/6/7/8/9)
The C8051F360/1/2/6/7/8/9 devices include a 10-bit current-mode Digital-to-Analog Converter (IDAC).
The maximum current output of the IDAC can be adjusted for three different current settings; 0.5 mA,
1 mA, and 2 mA. The IDAC is enabled or disabled with the IDA0EN bit in the IDA0 Control Register (see
SFR Definition 6.1). When IDA0EN is set to ‘0’, the IDAC port pin (P0.4 for C8051F360, P0.1 for
C8051F361/2/6/7/8/9) behaves as a normal GPIO pin. When IDA0EN is set to ‘1’, the digital output drivers
and weak pullup for the IDAC pin are automatically disabled, and the pin is connected to the IDAC output.
An internal bandgap bias generator is used to generate a reference current for the IDAC whenever it is
enabled. When using the IDAC, the appropriate bit in the P0SKIP register should be set to ‘1’ to force the
Crossbar to skip the IDAC pin.
6.1.
IDA0 Output Scheduling
IDA0 features a flexible output update mechanism which allows for seamless full-scale changes and supports jitter-free updates for waveform generation. Three update modes are provided, allowing IDAC output
updates on a write to IDA0H, on a Timer overflow, or on an external pin edge.
6.1.1. Update Output On-Demand
IDA0CN
CNVSTR
Timer 3
Timer 2
Timer 1
IDA0EN
IDA0CM2
IDA0CM1
IDA0CM0
Timer 0
IDA0H
In its default mode (IDA0CN.[6:4] = ‘111’) the IDA0 output is updated “on-demand” on a write to the highbyte of the IDA0 data register (IDA0H). It is important to note that writes to IDA0L are held in this mode,
and have no effect on the IDA0 output until a write to IDA0H takes place. If writing a full 10-bit word to the
IDAC data registers, the 10-bit data word is written to the low byte (IDA0L) and high byte (IDA0H) data registers. Data is latched into IDA0 after a write to the IDA0H register, so the write sequence should be
IDA0L followed by IDA0H if the full 10-bit resolution is required. The IDAC can be used in 8-bit mode by
initializing IDA0L to the desired value (typically 0x00), and writing data to only IDA0H (see Section 6.2 for
information on the format of the 10-bit IDAC data word within the 16-bit SFR space).
IDA0H
8
IDA0L
IDA0OMD1
IDA0OMD0
2
10
Latch
IDA0
Figure 6.1. IDA0 Functional Block Diagram
64
Rev. 1.2
IDA0
C8051F360/1/2/3/4/5/6/7/8/9
6.1.2. Update Output Based on Timer Overflow
Similar to the ADC operation, in which an ADC conversion can be initiated by a timer overflow independently of the processor, the IDAC outputs can use a Timer overflow to schedule an output update
event. This feature is useful in systems where the IDAC is used to generate a waveform of a defined sampling rate by eliminating the effects of variable interrupt latency and instruction execution on the timing of
the IDAC output. When the IDA0CM bits (IDA0CN.[6:4]) are set to ‘000’, ‘001’, ‘010’ or ‘011’, writes to both
IDAC data registers (IDA0L and IDA0H) are held until an associated Timer overflow event (Timer 0,
Timer 1, Timer 2 or Timer 3, respectively) occurs, at which time the IDA0H:IDA0L contents are copied to
the IDAC input latches, allowing the IDAC output to change to the new value.
6.1.3. Update Output Based on CNVSTR Edge
The IDAC output can also be configured to update on a rising edge, falling edge, or both edges of the
external CNVSTR signal. When the IDA0CM bits (IDA0CN.[6:4]) are set to ‘100’, ‘101’, or ‘110’, writes to
both IDAC data registers (IDA0L and IDA0H) are held until an edge occurs on the CNVSTR input pin. The
particular setting of the IDA0CM bits determines whether IDAC outputs are updated on rising, falling, or
both edges of CNVSTR. When a corresponding edge occurs, the IDA0H:IDA0L contents are copied to the
IDAC input latches, allowing the IDAC output to change to the new value.
6.2.
IDAC Output Mapping
The IDAC data registers (IDA0H and IDA0L) are left-justified, meaning that the eight MSBs of the IDAC
output word are mapped to bits 7–0 of the IDA0H register, and the two LSBs of the IDAC output word are
mapped to bits 7 and 6 of the IDA0L register. The data word mapping for the IDAC is shown in Figure 6.2.
IDA0H
D9
D8
D7
Input Data Word
(D9–D0)
0x000
0x001
0x200
0x3FF
D6
D5
IDA0L
D4
D3
Output Current
IDA0OMD[1:0] = ‘1x’
0 mA
1/1024 x 2 mA
512/1024 x 2 mA
1023/1024 x 2 mA
D2
D1
D0
Output Current
IDA0OMD[1:0] = ‘01’
0 mA
1/1024 x 1 mA
512/1024 x 1 mA
1023/1024 x 1 mA
Output Current
IDA0OMD[1:0] = ‘00’
0 mA
1/1024 x 0.5 mA
512/1024 x 0.5 mA
1023/1024 x 0.5 mA
Figure 6.2. IDA0 Data Word Mapping
The full-scale output current of the IDAC is selected using the IDA0OMD bits (IDA0CN[1:0]). By default,
the IDAC is set to a full-scale output current of 2 mA. The IDA0OMD bits can also be configured to provide
full-scale output currents of 1 mA or 0.5 mA, as shown in SFR Definition 6.1.
Rev. 1.2
65
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 6.1. IDA0CN: IDA0 Control
SFR Page:
all pages
SFR Address: 0xB9
R/W
R/W
IDA0EN
Bit7
R/W
R/W
IDA0CM
Bit6
Bit5
Bit4
R
R
–
–
Bit3
Bit2
R/W
R/W
IDA0OMD
Bit1
Reset Value
01110010
Bit0
Bit 7:
IDA0EN: IDA0 Enable.
0: IDA0 Disabled.
1: IDA0 Enabled.
Bits 6–4: IDA0CM[2:0]: IDA0 Update Source Select bits.
000: DAC output updates on Timer 0 overflow.
001: DAC output updates on Timer 1 overflow.
010: DAC output updates on Timer 2 overflow.
011: DAC output updates on Timer 3 overflow.
100: DAC output updates on rising edge of CNVSTR.
101: DAC output updates on falling edge of CNVSTR.
110: DAC output updates on any edge of CNVSTR.
111: DAC output updates on write to IDA0H. (default)
Bits 3–2: UNUSED. Read = 00b. Write = don’t care.
Bits 1–0: IDA0OMD[1:0]: IDA0 Output Mode Select bits.
00: 0.5 mA full-scale output current.
01: 1.0 mA full-scale output current.
1x: 2.0 mA full-scale output current. (default)
SFR Definition 6.2. IDA0H: IDA0 Data Word MSB
SFR Page:
all pages
SFR Address: 0x97
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bits 7–0: IDA0 Data Word High-Order Bits.
Bits 7–0 are the most-significant bits of the 10-bit IDA0 Data Word.
66
Rev. 1.2
Bit0
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 6.3. IDA0L: IDA0 Data Word LSB
SFR Page:
all pages
SFR Address: 0x96
R/W
Bit7
R/W
Bit6
R
R
R
R
R
R
Reset Value
—
—
—
—
—
—
00000000
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–6: IDA0 Data Word Low-Order Bits.
Lower 2 bits of the 10-bit Data Word.
Bits 5–0: UNUSED. Read = 000000b, Write = don’t care.
Table 6.1. IDAC Electrical Characteristics
–40 to +85 °C, VDD = 3.0 V Full-scale output current set to 2 mA unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
Static Performance
Resolution
10
Integral Nonlinearity
bits
—
±0.5
±2
LSB
—
±0.5
±1
LSB
Output Compliance Range
—
—
VDD – 1.2
V
Offset Error
—
0
—
LSB
–15
0
15
LSB
Full Scale Error Tempco
—
30
—
ppm/°C
VDD Power Supply
Rejection Ratio
—
6.5
—
µA/V
Output Settling Time to 1/2
IDA0H:L = 0x3FF to 0x000
LSB
—
5
—
µs
Startup Time
—
5
—
µs
—
—
±1
±1
—
—
%
%
—
—
—
2140
1140
640
—
—
—
µA
µA
µA
Differential Nonlinearity
Full Scale Error
Guaranteed Monotonic
2 mA Full Scale Output Current
Dynamic Performance
Gain Variation
1 mA Full Scale Output Current
0.5 mA Full Scale Output Current
Power Consumption
2 mA Full Scale Output Current
Power Supply Current (VDD
1 mA Full Scale Output Current
supplied to IDAC)
0.5 mA Full Scale Output Current
Rev. 1.2
67
C8051F360/1/2/3/4/5/6/7/8/9
7.
Voltage Reference (C8051F360/1/2/6/7/8/9)
The Voltage reference MUX on the C8051F360/1/2/6/7/8/9 devices is configurable to use an externally
connected voltage reference, the internal reference voltage generator, or the VDD power supply voltage
(see Figure 7.1). The REFSL bit in the Reference Control register (REF0CN) selects the reference source.
For an external source or the internal reference, REFSL should be set to ‘0’. To use VDD as the reference
source, REFSL should be set to ‘1’.
The BIASE bit enables the internal voltage bias generator, which is used by the ADC, Temperature Sensor,
internal oscillators, and Current DAC. This bias is enabled when any of the aforementioned peripherals are
enabled. The bias generator may be enabled manually by writing a ‘1’ to the BIASE bit in register
REF0CN; see SFR Definition 7.1 for REF0CN register details. The electrical specifications for the voltage
reference circuit are given in Table 7.1.
The internal voltage reference circuit consists of a 1.2 V, temperature stable bandgap voltage reference
generator and a gain-of-two output buffer amplifier. The internal voltage reference can be driven out on the
VREF pin by setting the REFBE bit in register REF0CN to a ‘1’ (see SFR Definition 7.1). The maximum
load seen by the VREF pin must be less than 200 µA to GND. When using the internal voltage reference,
bypass capacitors of 0.1 µF and 4.7 µF are recommended from the VREF pin to GND. If the internal reference is not used, the REFBE bit should be cleared to ‘0’. Electrical specifications for the internal voltage
reference are given in Table 7.1.
Important Note about the VREF Pin: Port pin P0.3 on the C8051F360 device and P0.0 on
C8051F361/2/6/7/89 devices is used as the external VREF input and as an output for the internal VREF.
When using either an external voltage reference or the internal reference circuitry, the port pin should be
configured as an analog pin, and skipped by the Digital Crossbar. To configure the port pin as an analog
pin, set the appropriate bit to ‘0’ in register P0MDIN. To configure the Crossbar to skip the VREF port pin,
set the appropriate bit to ‘1’ in register P0SKIP. Refer to Section “17. Port Input/Output” on page 184 for
REFSL
TEMPE
BIASE
REFBE
REF0CN
EN
VDD
External
Voltage
Reference
Circuit
R1
Bias Generator
IOSCE
N
EN
VREF
Temp Sensor
To ADC, IDAC,
Internal Oscillators
To Analog Mux
0
VREF
(to ADC)
GND
VDD
1
REFBE
4.7F
+
0.1F
EN
Internal
Reference
Recommended Bypass
Capacitors
Figure 7.1. Voltage Reference Functional Block Diagram
68
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
complete Port I/O configuration details. The TEMPE bit in register REF0CN enables/disables the temperature sensor. While disabled, the temperature sensor defaults to a high impedance state and any ADC0
measurements performed on the sensor result in meaningless data.
SFR Definition 7.1. REF0CN: Reference Control
SFR Page:
all pages
SFR Address: 0xD1
R
R
R
R
R/W
R/W
R/W
R/W
Reset Value
00000000
–
–
–
–
REFSL
TEMPE
BIASE
REFBE
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–4: UNUSED. Read = 0000b; Write = don’t care.
Bit 3:
REFSL: Voltage Reference Select.
This bit selects the source for the internal voltage reference.
0: VREF pin used as voltage reference.
1: VDD used as voltage reference.
Bit 2:
TEMPE: Temperature Sensor Enable Bit.
0: Internal Temperature Sensor off.
1: Internal Temperature Sensor on.
Bit 1:
BIASE: Internal Analog Bias Generator Enable Bit.
0: Internal Bias Generator off.
1: Internal Bias Generator on.
Bit 0:
REFBE: Internal Reference Buffer Enable Bit.
0: Internal Reference Buffer disabled.
1: Internal Reference Buffer enabled. Internal voltage reference driven on the VREF pin.
Rev. 1.2
69
C8051F360/1/2/3/4/5/6/7/8/9
Table 7.1. Voltage Reference Electrical Characteristics
VDD = 3.0 V; –40 to +85 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
2.35
2.42
2.50
V
VREF Short-Circuit Current
—
—
10
mA
VREF Temperature
Coefficient
—
25
—
ppm/°C
Internal Reference (REFBE = 1)
Output Voltage
25 °C ambient
Load Regulation
Load = 0 to 200 µA to AGND
—
3
—
µV/µA
VREF Turn-on Time 1
4.7 µF tantalum, 0.1 µF ceramic
bypass
—
7.5
—
ms
VREF Turn-on Time 2
0.1 µF ceramic bypass
—
200
—
µs
—
1.4
—
mV/V
0
—
VDD
V
—
3
—
µA
Power Supply Rejection
External Reference (REFBE = 0)
Input Voltage Range
Input Current
Sample Rate = 200 ksps; VREF =
3.0 V
Power Specifications
ADC Bias Generator
BIASE = ‘1’ or AD0EN = ‘1’ or
IOSCEN = ‘1’
—
100
150
µA
Reference Bias Generator
REFBE = ‘1’ or TEMPE = ‘1’ or
IDA0EN = ‘1’
—
30
50
µA
70
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
8.
Comparators
C8051F36x devices include two on-chip programmable voltage comparators, Comparator0 and Comparator1, shown in Figure 8.1 and Figure 8.2 (Note: the port pin Comparator inputs differ between C8051F36x
devices. The first Port I/O pin shown is for C8051F360/3 devices).
The comparators offer programmable response time and hysteresis, an analog input multiplexer, and two
outputs that are optionally available at the Port pins: a synchronous “latched” output (CP0 and CP1), or an
asynchronous “raw” output (CP0A and CP1A). The asynchronous CP0A and CP1A signals are available
even when the system clock is not active. This allows the Comparators to operate and generate an output
with the device in STOP mode. When assigned to a Port pin, the Comparator outputs may be configured
as open drain or push-pull (see Section “17.2. Port I/O Initialization” on page 188). Comparator0 may also
be used as a reset source (see Section “12.5. Comparator0 Reset” on page 132).
The Comparator inputs are selected in the CPT0MX and CPT1MX registers (SFR Definition 8.2 and SFR
Definition 8.5). The CMXnP1–CMXnP0 bits select the Comparator positive input; the CMXnN1–CMXnN0
bits select the Comparator negative input.
Important Note About Comparator Inputs: The Port pins selected as comparator inputs should be configured as analog inputs in their associated Port configuration register, and configured to be skipped by the
Crossbar (for details on Port configuration, see Section “17.3. General Purpose Port I/O” on page 191).
CP0EN
CPT0CN
CP0OUT
CMX0N3
CMX0N1
CMX0N0
VDD
CP0HYP1
CP0HYP0
CP0HYN1
CP0HYN0
CMX0P1
CMX0P0
P1.4 / P1.0
P2.3 / P1.4
CP0 +
CP0
+
P3.1 / P2.0
D
-
P3.5 / P2.4
SET
CLR
D
Q
Q
SET
CLR
Q
Q
Crossbar
(SYNCHRONIZER)
GND
P1.5 / P1.1
P2.4 / P1.5
CP0A
Reset
Decision
Tree
CP0 -
CP0RIF
P3.2 / P2.1
CP0FIF
P3.6 / P2.5
CPT0MD
CPT0MX
CMX0N2
CP0RIF
CP0FIF
0
CP0EN
EA
1
0
0
0
1
1
CP0
Interrupt
1
CP0RIE
CP0FIE
CP0MD1
CP0MD0
Figure 8.1. Comparator0 Functional Block Diagram
Rev. 1.2
71
C8051F360/1/2/3/4/5/6/7/8/9
CP1EN
CPT1CN
CPT1MX
CP1OUT
CMX1N1
CMX1N0
CP1RIF
VDD
CP1FIF
CP1HYP1
CP1HYP0
CP1HYN1
CP1HYN0
CMX1P1
CMX1P0
P2.0 / P1.2
P2.5 / P1.6
CP1 +
CP1
+
P3.3 / P2.2
D
-
P3.7 / P2.6
SET
CLR
Q
D
Q
SET
CLR
Q
Q
Crossbar
(SYNCHRONIZER)
GND
CP1A
P2.1 / P1.3
P2.6 / P1.7
CP1 -
CP1RIF
P3.4 / P2.3
CP1FIF
CPT1MD
P4.0 / P2.7
0
CP1EN
EA
1
0
0
0
1
1
CP1
Interrupt
1
CP1RIE
CP1FIE
CP1MD1
CP1MD0
Figure 8.2. Comparator1 Functional Block Diagram
A Comparator output can be polled in software, used as an interrupt source, and/or routed to a Port pin.
When routed to a Port pin, the Comparator outputs are available asynchronous or synchronous to the system clock; the asynchronous outputs are available even in STOP mode (with no system clock active).
When disabled, the Comparator outputs (if assigned to a Port I/O pin via the Crossbar) default to the logic
low state, and their supply current falls to less than 100 nA. See Section “17.1. Priority Crossbar Decoder”
on page 186 for details on configuring Comparator outputs via the digital Crossbar. Comparator inputs can
be externally driven from –0.25 V to (VDD) + 0.25 V without damage or upset. The complete Comparator
electrical specifications are given in Table 8.1.
The Comparator response time may be configured in software via the CPT0MD and CPT1MD registers
(see SFR Definition 8.3 and SFR Definition 8.6). Selecting a longer response time reduces the Comparator
supply current. See Table 8.1 for complete timing and power consumption specifications.
72
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
VIN+
VIN-
CP0+
CP0-
+
CP0
_
OUT
CIRCUIT CONFIGURATION
Positive Hysteresis Voltage
(Programmed with CP0HYP Bits)
VIN-
INPUTS
Negative Hysteresis Voltage
(Programmed by CP0HYN Bits)
VIN+
VOH
OUTPUT
VOL
Negative Hysteresis
Disabled
Positive Hysteresis
Disabled
Maximum
Negative Hysteresis
Maximum
Positive Hysteresis
Figure 8.3. Comparator Hysteresis Plot
The Comparator hysteresis is software-programmable via the Comparator Control registers CPT0CN and
CPT1CN. The user can program both the amount of hysteresis voltage (referred to the input voltage) and
the positive and negative-going symmetry of this hysteresis around the threshold voltage.
The Comparator hysteresis is programmed using Bits3–0 in the Comparator Control registers CPT0CN
and CPT1CN (shown in SFR Definition 8.1 and SFR Definition 8.4). The amount of negative hysteresis
voltage is determined by the settings of the CP0HYN and CP1HYN bits. As shown in Figure 8.3, settings of
20, 10 or 5 mV of negative hysteresis can be programmed, or negative hysteresis can be disabled. In a
similar way, the amount of positive hysteresis is determined by the setting the CP0HYP and CP1HYP bits.
Comparator interrupts can be generated on both rising-edge and falling-edge output transitions. (For Interrupt enable and priority control, see Section “10. Interrupt Handler” on page 108). The CP0FIF or CP1FIF
flag is set to logic ‘1’ upon a Comparator falling-edge occurrence, and the CP0RIF or CP1RIF flag is set to
logic ‘1’ upon the Comparator rising-edge occurrence. Once set, these bits remain set until cleared by software. The Comparator rising-edge interrupt mask is enabled by setting CP0RIE or CP1RIE to a logic ‘1’.
The Comparator falling-edge interrupt mask is enabled by setting CP0FIE or CP1FIE to a logic ‘1’.
The output state of the Comparator can be obtained at any time by reading the CP0OUT or CP1OUT bit.
The Comparator is enabled by setting the CP0EN or CP1EN bit to logic ‘1’, and is disabled by clearing this
bit to logic ‘0’.
Note that false rising edges and falling edges can be detected when the comparator is first powered on or
if changes are made to the hysteresis or response time control bits. Therefore, it is recommended that the
rising-edge and falling-edge flags be explicitly cleared to logic ‘0’ a short time after the comparator is
enabled or its mode bits have been changed. This Power Up Time is specified in Table 8.1 on page 80.
Rev. 1.2
73
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 8.1. CPT0CN: Comparator0 Control
SFR Page:
all pages
SFR Address: 0x9B
R/W
R
R/W
R/W
CP0EN
CP0OUT
CP0RIF
CP0FIF
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
R/W
Bit3
Bit 7:
Bit2
Bit1
Bit0
CP0EN: Comparator0 Enable Bit.
0: Comparator0 Disabled.
1: Comparator0 Enabled.
Bit 6:
CP0OUT: Comparator0 Output State Flag.
0: Voltage on CP0+ < CP0–.
1: Voltage on CP0+ > CP0–.
Bit 5:
CP0RIF: Comparator0 Rising-Edge Flag. Must be cleared by software.
0: No Comparator0 Rising Edge has occurred since this flag was last cleared.
1: Comparator0 Rising Edge has occurred.
Bit 4:
CP0FIF: Comparator0 Falling-Edge Flag. Must be cleared by software.
0: No Comparator0 Falling-Edge has occurred since this flag was last cleared.
1: Comparator0 Falling-Edge has occurred.
Bits 3–2: CP0HYP1–0: Comparator0 Positive Hysteresis Control Bits.
00: Positive Hysteresis Disabled.
01: Positive Hysteresis = 5 mV.
10: Positive Hysteresis = 10 mV.
11: Positive Hysteresis = 20 mV.
Bits 1–0: CP0HYN1–0: Comparator0 Negative Hysteresis Control Bits.
00: Negative Hysteresis Disabled.
01: Negative Hysteresis = 5 mV.
10: Negative Hysteresis = 10 mV.
11: Negative Hysteresis = 20 mV.
74
Reset Value
CP0HYP1 CP0HYP0 CP0HYN1 CP0HYN0 00000000
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 8.2. CPT0MX: Comparator0 MUX Selection
SFR Page:
all pages
SFR Address: 0x9F
R/W
R/W
–
–
Bit7
Bit6
R/W
R/W
CMX0N1 CMX0N0
Bit5
Bit4
R/W
R/W
R/W
R/W
Reset Value
–
–
CMX0P1
CMX0P0
11111111
Bit3
Bit2
Bit1
Bit0
Bits 7–6: UNUSED. Read = 11b, Write = don’t care.
Bits 5–4: CMX0N1–CMX0N0: Comparator0 Negative Input MUX Select.
These bits select which Port pin is used as the Comparator0 negative input.
CMX0N1 CMX0N0
0
0
1
1
0
1
0
1
C8051F360/3
Negative Input
P1.5
P2.4
P3.2
P3.6
C8051F361/2/4/5/6/7/8/9
Negative Input
P1.1
P1.5
P2.1
P2.5
Bits 3–2: UNUSED. Read = 11b, Write = don’t care.
Bits 1–0: CMX0P3–CMX0P0: Comparator0 Positive Input MUX Select.
These bits select which Port pin is used as the Comparator0 positive input.
CMX0P1 CMX0P0
0
0
1
1
0
1
0
1
C8051F360/3
Positive Input
P1.4
P2.3
P3.1
P3.5
Rev. 1.2
C8051F361/2/4/5/6/7/8/9
Positive Input
P1.0
P1.4
P2.0
P2.4
75
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 8.3. CPT0MD: Comparator0 Mode Selection
SFR Page:
all pages
SFR Address: 0x9D
R
R
R/W
R/W
R
R
–
–
CP0RIE
CP0FIE
–
–
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
R/W
76
CP0MD1
0
0
1
1
CP0MD0
0
1
0
1
Bit1
CP0 Response Time (TYP)
100 ns
175 ns
320 ns
1050 ns
Rev. 1.2
Reset Value
CP0MD1 CP0MD0 00000010
Bits 7–6: UNUSED. Read = 00b, Write = don’t care.
Bit 5:
CP0RIE: Comparator0 Rising-Edge Interrupt Enable.
0: Comparator0 Rising-edge interrupt disabled.
1: Comparator0 Rising-edge interrupt enabled.
Bit 4:
CP0FIE: Comparator0 Falling-Edge Interrupt Enable.
0: Comparator0 Falling-edge interrupt disabled.
1: Comparator0 Falling-edge interrupt enabled.
Bits 3–2: UNUSED. Read = 00b, Write = don’t care.
Bits 1–0: CP0MD1–CP0MD0: Comparator0 Mode Select
These bits select the response time for Comparator0.
Mode
0
1
2
3
R/W
Bit0
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 8.4. CPT1CN: Comparator1 Control
SFR Page:
all pages
SFR Address: 0x9A
R/W
R
R/W
R/W
CP1EN
CP1OUT
CP1RIF
CP1FIF
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
R/W
Reset Value
CP1HYP1 CP1HYP0 CP1HYN1 CP1HYN0 00000000
Bit3
Bit2
Bit1
Bit0
Bit 7:
CP1EN: Comparator1 Enable Bit.
0: Comparator1 Disabled.
1: Comparator1 Enabled.
Bit 6:
CP1OUT: Comparator1 Output State Flag.
0: Voltage on CP1+ < CP1–.
1: Voltage on CP1+ > CP1–.
Bit 5:
CP1RIF: Comparator1 Rising-Edge Flag. Must be cleared by software.
0: No Comparator1 Rising Edge has occurred since this flag was last cleared.
1: Comparator1 Rising Edge has occurred.
Bit 4:
CP1FIF: Comparator1 Falling-Edge Flag. Must be cleared by software.
0: No Comparator1 Falling-Edge has occurred since this flag was last cleared.
1: Comparator1 Falling-Edge has occurred.
Bits 3–2: CP1HYP1–0: Comparator1 Positive Hysteresis Control Bits.
00: Positive Hysteresis Disabled.
01: Positive Hysteresis = 5 mV.
10: Positive Hysteresis = 10 mV.
11: Positive Hysteresis = 20 mV.
Bits 1–0: CP1HYN1–0: Comparator1 Negative Hysteresis Control Bits.
00: Negative Hysteresis Disabled.
01: Negative Hysteresis = 5 mV.
10: Negative Hysteresis = 10 mV.
11: Negative Hysteresis = 20 mV.
Rev. 1.2
77
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 8.5. CPT1MX: Comparator1 MUX Selection
SFR Page:
all pages
SFR Address: 0x9E
R/W
R/W
–
–
Bit7
Bit6
R/W
R/W
CMX1N1 CMX1N0
Bit5
Bit4
R/W
R/W
R/W
R/W
Reset Value
–
–
CMX1P1
CMX1P0
11111111
Bit3
Bit2
Bit1
Bit0
Bits 7–6: UNUSED. Read = 11b, Write = don’t care.
Bits 5–4: CMX1N1–CMX1N0: Comparator1 Negative Input MUX Select.
These bits select which Port pin is used as the Comparator1 negative input.
CMX1N1 CMX1N0
0
0
1
1
0
1
0
1
C8051F360/3
Negative Input
P2.1
P2.6
P3.4
P4.0
C8051F361/2/4/5/6/7/8/9
Negative Input
P1.3
P1.7
P2.3
P2.7
Bits 3–2: UNUSED. Read = 11b, Write = don’t care.
Bits 1–0: CMX1P1–CMX1P0: Comparator1 Positive Input MUX Select.
These bits select which Port pin is used as the Comparator1 positive input.
CMX1P1 CMX1P0
0
0
1
1
78
0
1
0
1
C8051F360/3
Positive Input
P2.0
P2.5
P3.3
P3.7
Rev. 1.2
C8051F361/2/4/5/6/7/8/9
Positive Input
P1.2
P1.6
P2.2
P2.6
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 8.6. CPT1MD: Comparator1 Mode Selection
SFR Page:
all pages
SFR Address: 0x9C
R
R
R/W
R/W
R
R
–
–
CP1RIE
CP1FIE
–
–
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
R/W
R/W
Reset Value
CP1MD1 CP1MD0 00000010
Bit1
Bit0
Bits 7–6: UNUSED. Read = 00b, Write = don’t care.
Bit 5:
CP1RIE: Comparator1 Rising-Edge Interrupt Enable.
0: Comparator1 Rising-edge interrupt disabled.
1: Comparator1 Rising-edge interrupt enabled.
Bit 4:
CP1FIE: Comparator1 Falling-Edge Interrupt Enable.
0: Comparator1 Falling-edge interrupt disabled.
1: Comparator1 Falling-edge interrupt enabled.
Bits 3–2: UNUSED. Read = 00b, Write = don’t care.
Bits 1–0: CP1MD1–CP1MD0: Comparator1 Mode Select
These bits select the response time for Comparator1.
Mode
0
1
2
3
CP1MD1
0
0
1
1
CP1MD0
0
1
0
1
CP1 Response Time (TYP)
100 ns
175 ns
320 ns
1050 ns
Rev. 1.2
79
C8051F360/1/2/3/4/5/6/7/8/9
Table 8.1. Comparator Electrical Characteristics
VDD = 3.0 V, –40 to +85 °C unless otherwise noted.
Parameter
Conditions
Min
Typ
Max
Units
Response Time:
Mode 0, Vcm* = 1.5 V
CPx+ – CPx– = 100 mV
—
100
—
ns
CPx+ – CPx– = –100 mV
—
250
—
ns
Response Time:
Mode 1, Vcm* = 1.5 V
CPx+ – CPx– = 100 mV
—
175
—
ns
CPx+ – CPx– = –100 mV
—
500
—
ns
Response Time:
Mode 2, Vcm* = 1.5 V
CPx+ – CPx– = 100 mV
—
320
—
ns
CPx+ – CPx– = –100 mV
—
1100
—
ns
Response Time:
Mode 3, Vcm* = 1.5 V
CPx+ – CPx– = 100 mV
—
1050
—
ns
CPx+ – CPx– = –100 mV
—
5200
—
ns
—
1.26
5
mV/V
Common-Mode Rejection Ratio
Positive Hysteresis 1
CPxHYP1–0 = 00
—
0
1
mV
Positive Hysteresis 2
CPxHYP1–0 = 01
1
5
10
mV
Positive Hysteresis 3
CPxHYP1–0 = 10
6
10
20
mV
Positive Hysteresis 4
CPxHYP1–0 = 11
12
20
30
mV
Negative Hysteresis 1
CPxHYN1–0 = 00
—
0
1
mV
Negative Hysteresis 2
CPxHYN1–0 = 01
1
5
10
mV
Negative Hysteresis 3
CPxHYN1–0 = 10
6
10
20
mV
Negative Hysteresis 4
CPxHYN1–0 = 11
12
20
30
mV
–0.25
—
VDD + 0.25
V
Input Capacitance
—
4
—
pF
Input Bias Current
—
0.001
—
nA
Input Offset Voltage
–5
—
+5
mV
Power Supply Rejection
—
0.3
—
mV/V
Power-up Time
—
10
—
µs
Mode 0
—
11.4
20
µA
Mode 1
—
4.6
10
µA
Mode 2
—
1.9
5
µA
Mode 3
—
0.4
2.5
µA
Inverting or Non-Inverting Input
Voltage Range
Power Supply
Supply Current at DC
*Note: Vcm is the common-mode voltage on CPx+ and CPx–.
80
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
9.
CIP-51 Microcontroller
The MCU system controller core is the CIP-51 microcontroller. The CIP-51 is fully compatible with the
MCS-51™ instruction set; standard 803x/805x assemblers and compilers can be used to develop software. The MCU family has a superset of all the peripherals included with a standard 8051. Included are
five 16-bit counter/timers (see description in Section 21), one full-duplex UART (see description in Section
19), 256 bytes of internal RAM, 128 byte Special Function Register (SFR) address space (see Section
9.4.6), and up to four byte-wide and one 7-bit-wide I/O Ports (see description in Section 17). The CIP-51
also includes on-chip debug hardware (see description in Section 24), and interfaces directly with the
MCU’s analog and digital subsystems providing a complete data acquisition or control-system solution in a
single integrated circuit.
The CIP-51 Microcontroller core implements the standard 8051 organization and peripherals as well as
additional custom peripherals and functions to extend its capability (see Figure 9.1 for a block diagram).
- Fully Compatible with MCS-51 Instruction
Set
- 100 or 50 MIPS Peak Using the On-Chip
PLL
- 256 Bytes of Internal RAM
- 8/4 Byte-Wide I/O Ports
-
Extended Interrupt Handler
Reset Input
Power Management Modes
On-chip Debug Logic
The CIP-51 includes the following features:
9.1.
Performance
The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system
clock cycles to execute, and usually have a maximum system clock of 12 MHz. By contrast, the CIP-51
core executes 70% of its instructions in one or two system clock cycles, with no instructions taking more
than eight system clock cycles.
With the CIP-51's system clock running at 100 MHz, it has a peak throughput of 100 MIPS. The CIP-51
has a total of 109 instructions. The table below shows the total number of instructions that require each
execution time.
Clocks to Execute
1
2
2/3
3
3/4
4
4/5
5
8
Number of Instructions
26
50
5
14
7
3
1
2
1
Rev. 1.2
81
C8051F360/1/2/3/4/5/6/7/8/9
DATA BUS
D8
TMP2
B REGISTER
STACK POINTER
SRAM
ADDRESS
REGISTER
PSW
SRAM
(256 X 8)
D8
D8
D8
ALU
D8
D8
TMP1
ACCUMULATOR
D8
D8
D8
DATA BUS
DATA BUS
SFR_ADDRESS
BUFFER
D8
DATA POINTER
D8
D8
SFR
BUS
INTERFACE
SFR_CONTROL
SFR_WRITE_DATA
SFR_READ_DATA
DATA BUS
PC INCREMENTER
PROGRAM COUNTER (PC)
PRGM. ADDRESS REG.
PIPELINE
RESET
MEM_CONTROL
A16
MEMORY
INTERFACE
MEM_WRITE_DATA
MEM_READ_DATA
D8
CONTROL
LOGIC
SYSTEM_IRQs
CLOCK
D8
STOP
IDLE
MEM_ADDRESS
D8
POWER CONTROL
REGISTER
INTERRUPT
INTERFACE
EMULATION_IRQ
D8
Figure 9.1. CIP-51 Block Diagram
9.2.
Programming and Debugging Support
A C2-based serial interface is provided for in-system programming of the Flash program memory and communication with on-chip debug support logic. The re-programmable Flash can also be read and changed
by the application software using the MOVC and MOVX instructions. This feature allows program memory
to be used for non-volatile data storage as well as updating program code under software control.
The on-chip debug support logic facilitates full speed in-circuit debugging, allowing the setting of hardware
breakpoints and watch points, starting, stopping and single stepping through program execution (including
interrupt service routines), examination of the program's call stack, and reading/writing the contents of registers and memory. This method of on-chip debug is completely non-intrusive and non-invasive, requiring
no RAM, Stack, timers, or other on-chip resources.
The CIP-51 is supported by development tools from Silicon Labs and third party vendors. Silicon Labs provides an integrated development environment (IDE) including editor, macro assembler, debugger and programmer. The IDE's debugger and programmer interface to the CIP-51 via its C2 interface to provide fast
and efficient in-system device programming and debugging. Third party macro assemblers and C compilers are also available.
82
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C8051F360/1/2/3/4/5/6/7/8/9
9.3.
Instruction Set
The instruction set of the CIP-51 System Controller is fully compatible with the standard MCS-51™ instruction set; standard 8051 development tools can be used to develop software for the CIP-51. All CIP-51
instructions are the binary and functional equivalent of their MCS-51™ counterparts, including opcodes,
addressing modes and effect on PSW flags. However, instruction timing is different than that of the standard 8051.
9.3.1. Instruction and CPU Timing
In many 8051 implementations, a distinction is made between machine cycles and clock cycles, with
machine cycles varying from 2 to 12 clock cycles in length. However, the CIP-51 implementation is based
solely on clock cycle timing. All instruction timings are specified in terms of clock cycles.
Due to the pipelined architecture of the CIP-51, most instructions execute in the same number of clock
cycles as there are program bytes in the instruction. Conditional branch instructions take one less clock
cycle to complete when the branch is not taken as opposed to when the branch is taken. Table 9.1 is the
CIP-51 Instruction Set Summary, which includes the mnemonic, number of bytes, and number of clock
cycles for each instruction.
9.3.2. MOVX Instruction and Program Memory
In the CIP-51, the MOVX instruction serves three purposes: accessing on-chip XRAM, accessing off-chip
XRAM, and accessing on-chip program Flash memory. The Flash access feature provides a mechanism
for user software to update program code and use the program memory space for non-volatile data storage (see Section “13. Flash Memory” on page 136). The External Memory Interface provides a fast access
to off-chip XRAM (or memory-mapped peripherals) via the MOVX instruction. Refer to Section
“15. External Data Memory Interface and On-Chip XRAM” on page 154 for details.
Table 9.1. CIP-51 Instruction Set Summary
Mnemonic
Description
ADD A, Rn
ADD A, direct
ADD A, @Ri
ADD A, #data
ADDC A, Rn
ADDC A, direct
ADDC A, @Ri
ADDC A, #data
SUBB A, Rn
SUBB A, direct
SUBB A, @Ri
SUBB A, #data
INC A
INC Rn
INC direct
INC @Ri
Arithmetic Operations
Add register to A
Add direct byte to A
Add indirect RAM to A
Add immediate to A
Add register to A with carry
Add direct byte to A with carry
Add indirect RAM to A with carry
Add immediate to A with carry
Subtract register from A with borrow
Subtract direct byte from A with borrow
Subtract indirect RAM from A with borrow
Subtract immediate from A with borrow
Increment A
Increment register
Increment direct byte
Increment indirect RAM
Rev. 1.2
Bytes
Clock
Cycles
1
2
1
2
1
2
1
2
1
2
1
2
1
1
2
1
1
2
2
2
1
2
2
2
1
2
2
2
1
1
2
2
83
C8051F360/1/2/3/4/5/6/7/8/9
Table 9.1. CIP-51 Instruction Set Summary (Continued)
Mnemonic
Description
DEC A
DEC Rn
DEC direct
DEC @Ri
INC DPTR
MUL AB
DIV AB
DA A
Decrement A
Decrement register
Decrement direct byte
Decrement indirect RAM
Increment Data Pointer
Multiply A and B
Divide A by B
Decimal adjust A
Logical Operations
AND Register to A
AND direct byte to A
AND indirect RAM to A
AND immediate to A
AND A to direct byte
AND immediate to direct byte
OR Register to A
OR direct byte to A
OR indirect RAM to A
OR immediate to A
OR A to direct byte
OR immediate to direct byte
Exclusive-OR Register to A
Exclusive-OR direct byte to A
Exclusive-OR indirect RAM to A
Exclusive-OR immediate to A
Exclusive-OR A to direct byte
Exclusive-OR immediate to direct byte
Clear A
Complement A
Rotate A left
Rotate A left through Carry
Rotate A right
Rotate A right through Carry
Swap nibbles of A
Data Transfer
Move Register to A
Move direct byte to A
Move indirect RAM to A
Move immediate to A
Move A to Register
Move direct byte to Register
Move immediate to Register
Move A to direct byte
Move Register to direct byte
Move direct byte to direct byte
ANL A, Rn
ANL A, direct
ANL A, @Ri
ANL A, #data
ANL direct, A
ANL direct, #data
ORL A, Rn
ORL A, direct
ORL A, @Ri
ORL A, #data
ORL direct, A
ORL direct, #data
XRL A, Rn
XRL A, direct
XRL A, @Ri
XRL A, #data
XRL direct, A
XRL direct, #data
CLR A
CPL A
RL A
RLC A
RR A
RRC A
SWAP A
MOV A, Rn
MOV A, direct
MOV A, @Ri
MOV A, #data
MOV Rn, A
MOV Rn, direct
MOV Rn, #data
MOV direct, A
MOV direct, Rn
MOV direct, direct
84
1
1
2
1
1
1
1
1
Clock
Cycles
1
1
2
2
1
4
8
1
1
2
1
2
2
3
1
2
1
2
2
3
1
2
1
2
2
3
1
1
1
1
1
1
1
1
2
2
2
2
3
1
2
2
2
2
3
1
2
2
2
2
3
1
1
1
1
1
1
1
1
2
1
2
1
2
2
2
2
3
1
2
2
2
1
2
2
2
2
3
Bytes
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Table 9.1. CIP-51 Instruction Set Summary (Continued)
Mnemonic
Description
MOV direct, @Ri
MOV direct, #data
MOV @Ri, A
MOV @Ri, direct
MOV @Ri, #data
MOV DPTR, #data16
MOVC A, @A+DPTR
MOVC A, @A+PC
MOVX A, @Ri
MOVX @Ri, A
MOVX A, @DPTR
MOVX @DPTR, A
PUSH direct
POP direct
XCH A, Rn
XCH A, direct
XCH A, @Ri
XCHD A, @Ri
Move indirect RAM to direct byte
Move immediate to direct byte
Move A to indirect RAM
Move direct byte to indirect RAM
Move immediate to indirect RAM
Load DPTR with 16-bit constant
Move code byte relative DPTR to A
Move code byte relative PC to A
Move external data (8-bit address) to A
Move A to external data (8-bit address)
Move external data (16-bit address) to A
Move A to external data (16-bit address)
Push direct byte onto stack
Pop direct byte from stack
Exchange Register with A
Exchange direct byte with A
Exchange indirect RAM with A
Exchange low nibble of indirect RAM with A
Boolean Manipulation
Clear Carry
Clear direct bit
Set Carry
Set direct bit
Complement Carry
Complement direct bit
AND direct bit to Carry
AND complement of direct bit to Carry
OR direct bit to carry
OR complement of direct bit to Carry
Move direct bit to Carry
Move Carry to direct bit
Jump if Carry is set
Jump if Carry is not set
Jump if direct bit is set
Jump if direct bit is not set
Jump if direct bit is set and clear bit
Program Branching
Absolute subroutine call
Long subroutine call
Return from subroutine
Return from interrupt
Absolute jump
Long jump
Short jump (relative address)
Jump indirect relative to DPTR
CLR C
CLR bit
SETB C
SETB bit
CPL C
CPL bit
ANL C, bit
ANL C, /bit
ORL C, bit
ORL C, /bit
MOV C, bit
MOV bit, C
JC rel
JNC rel
JB bit, rel
JNB bit, rel
JBC bit, rel
ACALL addr11
LCALL addr16
RET
RETI
AJMP addr11
LJMP addr16
SJMP rel
JMP @A+DPTR
2
3
1
2
2
3
1
1
1
1
1
1
2
2
1
2
1
1
Clock
Cycles
2
3
2
2
2
3
3
3
3
3
3
3
2
2
1
2
2
2
1
2
1
2
1
2
2
2
2
2
2
2
2
2
3
3
3
1
2
1
2
1
2
2
2
2
2
2
2
2/3*
2/3*
3/4*
3/4*
3/4*
2
3
1
1
2
3
2
1
3*
4*
5*
5*
3*
4*
3*
3*
Bytes
Rev. 1.2
85
C8051F360/1/2/3/4/5/6/7/8/9
Table 9.1. CIP-51 Instruction Set Summary (Continued)
Mnemonic
Description
Bytes
JZ rel
JNZ rel
CJNE A, direct, rel
CJNE A, #data, rel
Clock
Cycles
2/3*
2/3*
3/4*
3/4*
Jump if A equals zero
2
Jump if A does not equal zero
2
Compare direct byte to A and jump if not equal
3
Compare immediate to A and jump if not equal
3
Compare immediate to Register and jump if not
CJNE Rn, #data, rel
3
3/4*
equal
Compare immediate to indirect and jump if not
CJNE @Ri, #data, rel
3
4/5*
equal
DJNZ Rn, rel
Decrement Register and jump if not zero
2
2/3*
DJNZ direct, rel
Decrement direct byte and jump if not zero
3
3/4*
NOP
No operation
1
1
* Branch instructions will incur a cache-miss penalty if the branch target location is not already stored in
the Branch Target Cache. See Section “14. Branch Target Cache” on page 146 for more details.
Notes on Registers, Operands and Addressing Modes:
Rn - Register R0-R7 of the currently selected register bank.
@Ri - Data RAM location addressed indirectly through R0 or R1.
rel - 8-bit, signed (2s complement) offset relative to the first byte of the following instruction. Used by
SJMP and all conditional jumps.
direct - 8-bit internal data location’s address. This could be a direct-access Data RAM location (0x000x7F) or an SFR (0x80-0xFF).
#data - 8-bit constant
#data16 - 16-bit constant
bit - Direct-accessed bit in Data RAM or SFR
addr11 - 11-bit destination address used by ACALL and AJMP. The destination must be within the same
2K-byte page of program memory as the first byte of the following instruction.
addr16 - 16-bit destination address used by LCALL and LJMP. The destination may be anywhere within
the 64K-byte program memory space.
There is one unused opcode (0xA5) that performs the same function as NOP.
All mnemonics copyrighted © Intel Corporation 1980.
86
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
9.4.
Memory Organization
The memory organization of the CIP-51 System Controller is similar to that of a standard 8051. There are
two separate memory spaces: program memory and data memory. Program and data memory share the
same address space but are accessed via different instruction types. There are 256 bytes of internal data
memory and 32k bytes (C8051F360/1/2/3/4/5/6/7) or 16k bytes (C8051F368/9) of internal program memory address space implemented within the CIP-51. The CIP-51 memory organization is shown in
Figure 9.2.
PROGRAM MEMORY
DATA MEMORY
INTERNAL DATA ADDRESS SPACE
C8051F360/1/2/3/4/5/6/7
RESERVED
0x7C00
0x7BFF
0xFF
0x80
0x7F
Upper 128 RAM
(Indirect Addressing
Only)
(Direct and Indirect
Addressing)
FLASH
0x30
0x2F
(In-System
Programmable in 1024
Byte Sectors)
0x20
0x1F
0x00
Bit Addressable
Special Function
Register's
(Direct Addressing Only)
Lower 128 RAM
(Direct and Indirect
Addressing)
General Purpose
Registers
0x0000
EXTERNAL DATA ADDRESS SPACE
C8051F368/9
RESERVED
0xFFFF
0x4000
0x3FFF
Same 1024 bytes as from
0x0000 to 0x03FF, wrapped
on 1024-byte boundaries
FLASH
(In-System
Programmable in 1024
Byte Sectors)
0x0000
0x0400
0x03FF
0x0000
XRAM - 1024 Bytes
(accessable using MOVX
instruction)
Figure 9.2. Memory Map
9.4.1. Program Memory
The CIP-51 core has a 64 kB program memory space. The C8051F360/1/2/3/4/5/6/7 implement 32 kB of
this program memory space as in-system, re-programmable Flash memory, organized in a contiguous
block from addresses 0x0000 to 0x7BFF. Addresses above 0x7BFF are reserved on the 32 kB devices.
The C8051F368/9 implement 16 kB of Flash from addresses 0x0000 to 0x3FFF.
Program memory is normally assumed to be read-only. However, the CIP-51 can write to program memory
by setting the Program Store Write Enable bit (PSCTL.0) and using the MOVX instruction. This feature provides a mechanism for the CIP-51 to update program code and use the program memory space for nonvolatile data storage. Refer to Section “13. Flash Memory” on page 136 for further details.
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9.4.2. Data Memory
The CIP-51 implements 256 bytes of internal RAM mapped into the data memory space from 0x00 through
0xFF. The lower 128 bytes of data memory are used for general purpose registers and memory. Either
direct or indirect addressing may be used to access the lower 128 bytes of data memory. Locations 0x00
through 0x1F are addressable as four banks of general purpose registers, each bank consisting of eight
byte-wide registers. The next 16 bytes, locations 0x20 through 0x2F, may either be addressed as bytes or
as 128 bit locations accessible with the direct addressing mode.
The upper 128 bytes of data memory are accessible only by indirect addressing. This region occupies the
same address space as the Special Function Registers (SFR) but is physically separate from the SFR
space. The addressing mode used by an instruction when accessing locations above 0x7F determines
whether the CPU accesses the upper 128 bytes of data memory space or the SFR’s. Instructions that use
direct addressing will access the SFR space. Instructions using indirect addressing above 0x7F access the
upper 128 bytes of data memory. Figure 9.2 illustrates the data memory organization of the CIP-51.
9.4.3. General Purpose Registers
The lower 32 bytes of data memory, locations 0x00 through 0x1F, may be addressed as four banks of general-purpose registers. Each bank consists of eight byte-wide registers designated R0 through R7. Only
one of these banks may be enabled at a time. Two bits in the program status word, RS0 (PSW.3) and RS1
(PSW.4), select the active register bank (see description of the PSW in SFR Definition 9.8). This allows
fast context switching when entering subroutines and interrupt service routines. Indirect addressing modes
use registers R0 and R1 as index registers.
9.4.4. Bit Addressable Locations
In addition to direct access to data memory organized as bytes, the sixteen data memory locations at 0x20
through 0x2F are also accessible as 128 individually addressable bits. Each bit has a bit address from
0x00 to 0x7F. Bit 0 of the byte at 0x20 has bit address 0x00 while bit 7 of the byte at 0x20 has bit address
0x07. Bit 7 of the byte at 0x2F has bit address 0x7F. A bit access is distinguished from a full byte access by
the type of instruction used (bit source or destination operands as opposed to a byte source or destination). The MCS-51™ assembly language allows an alternate notation for bit addressing of the form XX.B
where XX is the byte address and B is the bit position within the byte.
For example, the instruction:
MOV
C, 22.3h
moves the Boolean value at 0x13 (bit 3 of the byte at location 0x22) into the Carry flag.
9.4.5. Stack
A programmer's stack can be located anywhere in the 256 byte data memory. The stack area is designated
using the Stack Pointer (SP, address 0x81) SFR. The SP will point to the last location used. The next value
pushed on the stack is placed at SP+1 and then SP is incremented. A reset initializes the stack pointer to
location 0x07; therefore, the first value pushed on the stack is placed at location 0x08, which is also the
first register (R0) of register bank 1. Thus, if more than one register bank is to be used, the SP should be
initialized to a location in the data memory not being used for data storage. The stack depth can extend up
to 256 bytes.
The MCUs also have built-in hardware for a stack record which is accessed by the debug logic. The stack
record is a 32-bit shift register, where each PUSH or increment SP pushes one record bit onto the register,
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and each CALL pushes two record bits onto the register. (A POP or decrement SP pops one record bit,
and a RET pops two record bits, also.) The stack record circuitry can also detect an overflow or underflow
on the 32-bit shift register, and can notify the debug software even with the MCU running at speed.
9.4.6. Special Function Registers
The direct-access data memory locations from 0x80 to 0xFF constitute the special function registers
(SFR’s). The SFR’s provide control and data exchange with the CIP-51's resources and peripherals. The
CIP-51 duplicates the SFR’s found in a typical 8051 implementation as well as implementing additional
SFR’s used to configure and access the sub-systems unique to the MCU. This allows the addition of new
functionality while retaining compatibility with the MCS-51™ instruction set. Table 9.2 lists the SFR’s implemented in the CIP-51 System Controller.
The SFR registers are accessed whenever the direct addressing mode is used to access memory locations from 0x80 to 0xFF. SFR’s with addresses ending in 0x0 or 0x8 (e.g. P0, TCON, P1, SCON, IE, etc.)
are bit-addressable as well as byte-addressable. All other SFR’s are byte-addressable only. Unoccupied
addresses in the SFR space are reserved for future use. Accessing these areas will have an indeterminate
effect and should be avoided. Refer to the corresponding pages of the data sheet, as indicated in
Table 9.3, for a detailed description of each register.
9.4.6.1. SFR Paging
The CIP-51 features SFR paging, allowing the device to map many SFR’s into the 0x80 to 0xFF memory
address space. The SFR memory space has 256 pages. In this way, each memory location from 0x80 to
0xFF can access up to 256 SFR’s. The C8051F36x family of devices utilizes two SFR pages: 0 and F. SFR
pages are selected using the Special Function Register Page Selection register, SFRPAGE (see SFR Definition 9.2). The procedure for reading and writing an SFR is as follows:
1. Select the appropriate SFR page number using the SFRPAGE register.
2. Use direct accessing mode to read or write the special function register (MOV instruction).
9.4.6.2. Interrupts and SFR Paging
When an interrupt occurs, the SFR Page Register will automatically switch to SFR page 0, where all registers containing the interrupt flag bits are accessible. The automatic SFR Page switch function conveniently
removes the burden of switching SFR pages from the interrupt service routine. Upon execution of the RETI
instruction, the SFR page is automatically restored to the SFR Page in use prior to the interrupt. This is
accomplished via a three-byte SFR Page Stack. The top byte of the stack is SFRPAGE, the current SFR
Page. The second byte of the SFR Page Stack is SFRNEXT. The third, or bottom byte of the SFR Page
Stack is SFRLAST. On interrupt, the current SFRPAGE value is pushed to the SFRNEXT byte, and the
value of SFRNEXT is pushed to SFRLAST. Hardware then loads SFRPAGE with the SFR Page containing
the flag bit associated with the interrupt. On a return from interrupt, the SFR Page Stack is popped resulting in the value of SFRNEXT returning to the SFRPAGE register, thereby restoring the SFR page context
without software intervention. The value in SFRLAST (0x00 if there is no SFR Page value in the bottom of
the stack) of the stack is placed in SFRNEXT register. If desired, the values stored in SFRNEXT and SFRLAST may be modified during an interrupt, enabling the CPU to return to a different SFR Page upon execution of the RETI instruction (on interrupt exit). Modifying registers in the SFR Page Stack does not cause
a push or pop of the stack. Only interrupt calls and returns will cause push/pop operations on the SFR
Page Stack.
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SFRPGCN Bit
Interrupt
Logic
SFRPAGE
CIP-51
SFRNEXT
SFRLAST
Figure 9.3. SFR Page Stack
Automatic hardware switching of the SFR Page on interrupts may be enabled or disabled as desired using
the SFR Automatic Page Control Enable Bit located in the SFR Page Control Register (SFR0CN). This
function defaults to ‘enabled’ upon reset. In this way, the autoswitching function will be enabled unless disabled in software.
A summary of the SFR locations (address and SFR page) is provided in Table 9.2. in the form of an SFR
memory map. Each memory location in the map has an SFR page row, denoting the page in which that
SFR resides. Note that certain SFR’s are accessible from ALL SFR pages, and are denoted by the background shading in the table. For example, the Port I/O registers P0, P1, P2, and P3 all have a shaded
background, indicating these SFR’s are accessible from all SFR pages regardless of the SFRPAGE register value.
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9.4.6.3. SFR Page Stack Example
The following is an example that shows the operation of the SFR Page Stack during interrupts.
In this example, the SFR Page Control is left in the default enabled state (i.e., SFRPGEN = 1), and the
CIP-51 is executing in-line code that is writing values to OSCICN (SFR “OSCICN”, located at address
0xB6 on SFR Page 0x0F). The device is also using the Programmable Counter Array (PCA) and the 10-bit
ADC (ADC0) window comparator to monitor a voltage. The PCA is timing a critical control function in its
interrupt service routine (ISR), so its interrupt is enabled and is set to high priority. The ADC0 is monitoring
a voltage that is less important, but to minimize the software overhead its window comparator is being used
with an associated ISR that is set to low priority. At this point, the SFR page is set to access the OSCICN
SFR (SFRPAGE = 0x0F). See Figure 9.4 below.
SFR Page
Stack SFR's
0x0F
SFRPAGE
(OSCICN)
SFRNEXT
SFRLAST
Figure 9.4. SFR Page Stack While Using SFR Page 0x0F To Access OSCICN
While CIP-51 executes in-line code (writing values to OSCICN in this example), ADC0 Window Comparator Interrupt occurs. The CIP-51 vectors to the ADC0 Window Comparator ISR and pushes the current
SFR Page value (SFR Page 0x0F) into SFRNEXT in the SFR Page Stack. SFR page 0x00 is then automatically placed in the SFRPAGE register. SFRPAGE is considered the “top” of the SFR Page Stack. Software can now access the ADC0 SFR’s. Software may switch to any SFR Page by writing a new value to
the SFRPAGE register at any time during the ADC0 ISR to access SFR’s that are not on SFR Page 0x00.
See Figure 9.5 below.
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SFR Page 0x00
Automatically
pushed on stack in
SFRPAGE on ADC0
interrupt
0x00
SFRPAGE
SFRPAGE
pushed to
SFRNEXT
(ADC0)
0x0F
SFRNEXT
(OSCICN)
SFRLAST
Figure 9.5. SFR Page Stack After ADC0 Window Comparator Interrupt Occurs
While in the ADC0 ISR, a PCA interrupt occurs. Recall the PCA interrupt is configured as a high priority
interrupt, while the ADC0 interrupt is configured as a low priority interrupt. Thus, the CIP-51 will now vector
to the high priority PCA ISR. Upon doing so, the CIP-51 will automatically place SFR page 0x00 into the
SFRPAGE register. The value that was in the SFRPAGE register before the PCA interrupt (SFR Page 0x00
for ADC0) is pushed down the stack into SFRNEXT. Likewise, the value that was in the SFRNEXT register
before the PCA interrupt (in this case SFR Page 0x0F for OSCICN) is pushed down to the SFRLAST register, the “bottom” of the stack. Note that a value stored in SFRLAST (via a previous software write to the
SFRLAST register) will be overwritten. See Figure 9.6 below.
SFR Page 0x00
Automatically
pushed on stack in
SFRPAGE on PCA
interrupt
0x00
SFRPAGE
SFRPAGE
pushed to
SFRNEXT
(PCA)
0x00
SFRNEXT
SFRNEXT
pushed to
SFRLAST
(ADC0)
0x0F
SFRLAST
(OSCICN)
Figure 9.6. SFR Page Stack Upon PCA Interrupt Occurring During an ADC0 ISR
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On exit from the PCA interrupt service routine, the CIP-51 will return to the ADC0 Window Comparator
ISR. On execution of the RETI instruction, SFR Page 0x00 used to access the PCA registers will be automatically popped off of the SFR Page Stack, and the contents of the SFRNEXT register will be moved to
the SFRPAGE register. Software in the ADC0 ISR can continue to access SFR’s as it did prior to the PCA
interrupt. Likewise, the contents of SFRLAST are moved to the SFRNEXT register. Recall this was the
SFR Page value 0x0F being used to access OSCICN before the ADC0 interrupt occurred. See Figure 9.7
below.
SFR Page 0x00
Automatically
popped off of the
stack on return from
interrupt
0x00
SFRPAGE
SFRNEXT
popped to
SFRPAGE
(ADC0)
0x0F
SFRNEXT
SFRLAST
popped to
SFRNEXT
(OSCICN)
SFRLAST
Figure 9.7. SFR Page Stack Upon Return From PCA Interrupt
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On the execution of the RETI instruction in the ADC0 Window Comparator ISR, the value in SFRPAGE
register is overwritten with the contents of SFRNEXT. The CIP-51 may now access the OSCICN SFR bits
as it did prior to the interrupts occurring. See Figure 9.8 below.
SFR Page 0x00
Automatically
popped off of the
stack on return from
interrupt
0x0F
SFRPAGE
SFRNEXT
popped to
SFRPAGE
(OSCICN)
SFRNEXT
SFRLAST
Figure 9.8. SFR Page Stack Upon Return From ADC2 Window Interrupt
Note that in the above example, all three bytes in the SFR Page Stack are accessible via the SFRPAGE,
SFRNEXT, and SFRLAST special function registers. If the stack is altered while servicing an interrupt, it is
possible to return to a different SFR Page upon interrupt exit than selected prior to the interrupt call. Direct
access to the SFR Page stack can be useful to enable real-time operating systems to control and manage
context switching between multiple tasks.
Push operations on the SFR Page Stack only occur on interrupt service, and pop operations only occur on
interrupt exit (execution on the RETI instruction). The automatic switching of the SFRPAGE and operation
of the SFR Page Stack as described above can be disabled in software by clearing the SFR Automatic
Page Enable Bit (SFRPGEN) in the SFR Page Control Register (SFR0CN). See SFR Definition 9.1.
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SFR Definition 9.1. SFR0CN: SFR Page Control
SFR Page:
F
SFR Address: 0xE5
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Reserved Reserved Reserved Reserved Reserved Reserved Reserved SFRPGEN 00000001
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–1: RESERVED. Read = 0000000b. Must Write 0000000b.
Bit 0:
SFRPGEN: SFR Automatic Page Control Enable.
Upon interrupt, the C8051 Core will vector to the specified interrupt service routine and automatically switch to SFR page 0. This bit is used to control this autopaging function.
0: SFR Automatic Paging disabled. C8051 core will not automatically change to SFR page
0.
1: SFR Automatic Paging enabled. Upon interrupt, the C8051 will automatically switch to
SFR page 0.
SFR Definition 9.2. SFRPAGE: SFR Page
SFR Page:
all pages
SFR Address: 0xA7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: SFR Page Bits: Byte Represents the SFR Page the C8051 MCU uses when reading or modifying SFR’s.
Write: Sets the SFR Page.
Read: Byte is the SFR page the C8051 MCU is using.
When enabled in the SFR Page Control Register (SFR0CN), the C8051 will automatically
switch to SFR Page 0x00 and return to the previous SFR page upon return from interrupt
(unless SFR Stack was altered before a returning from the interrupt).
SFRPAGE is the top byte of the SFR Page Stack, and push/pop events of this stack are
caused by interrupts (and not by reading/writing to the SFRPAGE register)
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SFR Definition 9.3. SFRNEXT: SFR Next Register
SFR Page:
all pages
SFR Address: 0x85
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: SFR Page Stack Bits: SFR page context is retained upon interrupts/return from interrupts in
a 3 byte SFR Page Stack: SFRPAGE is the first entry, SFRNEXT is the second, and SFRLAST is the third entry. The SFR stack bytes may be used alter the context in the SFR Page
Stack, and will not cause the stack to ‘push’ or ‘pop’. Only interrupts and return from interrupts cause pushes and pops of the SFR Page Stack.
Write: Sets the SFR Page contained in the second byte of the SFR Stack. This will cause
the SFRPAGE SFR to have this SFR page value upon a return from interrupt.
Read: Returns the value of the SFR page contained in the second byte of the SFR stack.
This is the value that will go to the SFR Page register upon a return from interrupt.
SFR Definition 9.4. SFRLAST: SFR Last Register
SFR Page:
all pages
SFR Address: 0x86
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: SFR Page Stack Bits: SFR page context is retained upon interrupts/return from interrupts in
a 3 byte SFR Page Stack: SFRPAGE is the first entry, SFRNEXT is the second, and SFRLAST is the third entry. The SFR stack bytes may be used alter the context in the SFR Page
Stack, and will not cause the stack to ‘push’ or ‘pop’. Only interrupts and return from interrupts cause pushes and pops of the SFR Page Stack.
Write: Sets the SFR Page in the last entry of the SFR Stack. This will cause the SFRNEXT
SFR to have this SFR page value upon a return from interrupt.
Read: Returns the value of the SFR page contained in the last entry of the SFR stack.
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ADDRESS
SFR Page
Table 9.2. Special Function Register (SFR) Memory Map
F8
0
F
SPI0CN
PCA0L
PCA0H
F0
0
F
B
MAC0BL
P0MDIN
MAC0BH
P1MDIN
E8
0
F
ADC0CN
E0
0
F
ACC
P1MAT
XBR0
D8
0
F
PCA0CN
PCA0MD
PCA0CPM0 PCA0CPM1 PCA0CPM2 PCA0CPM3 PCA0CPM4 PCA0CPM5
D0
0
F
PSW
REF0CN
MAC0ACC0 MAC0ACC1 MAC0ACC2 MAC0ACC3 MAC0OVR
CCH0LC
CCH0MA
P0SKIP
P1SKIP
P2SKIP
C8
0
F
TMR2CN
CCH0TN
TMR2RLL
TMR2RLH
TMR2L
TMR2H
EIP1
MAC0STA
EIP2
C0
0
F
SMB0CN
SMB0CF
SMB0DAT
ADC0GTL
ADC0GTH
ADC0LTL
ADC0LTH
EMI0CF
B8
0
F
IP
IDA0CN
AMX0N
AMX0P
ADC0CF
ADC0L
ADC0H
OSCICL
B0
0
F
P3
P2MAT
PLL0MUL
P2MASK
PLL0FLT
PLL0CN
-
P4
FLSCL
OSCXCN
FLKEY
OSCICN
A8
0
F
IE
PLL0DIV
EMI0CN
-
FLSTAT
OSCLCN
A0
0
F
P2
SPI0CFG
SPI0CKR
SPI0DAT
MAC0AL
P0MDOUT
MAC0AH
P1MDOUT
P2MDOUT
SFRPAGE
98
0
F
SCON0
SBUF0
CPT1CN
CPT0CN
CPT1MD
CPT0MD
CPT1MX
CPT0MX
90
0
F
P1
TMR3CN
TMR3RLL
TMR3RLH
TMR3L
TMR3H
IDA0L
IDA0H
88
0
F
TCON
TMOD
TL0
TL1
TH0
TH1
CKCON
PSCTL
CLKSEL
80
0
F
P0
SP
DPL
DPH
CCH0CN
SFRNEXT
SFRLAST
PCON
0(8)
1(9)
2(A)
3(B)
4(C)
5(D)
6(E)
7(F)
0(8)
1(9)
2(A)
bit-addressable
3(B)
4(C)
5(D)
6(E)
PCA0CPL0 PCA0CPH0 PCA0CPL4 PCA0CPH4
P0MASK
P3MDIN
VDM0CN
PCA0CPL5 PCA0CPH5
EMI0TC
PCA0CPL1 PCA0CPH1 PCA0CPL2 PCA0CPH2 PCA0CPL3 PCA0CPH3
RSTSRC
P1MASK
XBR1
P0MAT
P2MDIN
7(F)
-
IT01CF
SFR0CN
EIE1
EIE2
MAC0CF
P3SKIP
MAC0RNDL MAC0RNDH
P4MDOUT P3MDOUT
shaded SFRs are accessible on all SFR Pages regardless of the contents of SFRPAGE
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Table 9.3. Special Function Registers
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
SFR
Page
Description
Page No.
ACC
0xE0
All Pages Accumulator
page 105
ADC0CF
0xBC
All Pages ADC0 Configuration
page 571
ADC0CN
0xE8
All Pages ADC0 Control
page 581
ADC0GTH
0xC4
All Pages ADC0 Greater-Than High Byte
page 591
ADC0GTL
0xC3
All Pages ADC0 Greater-Than Low Byte
page 591
ADC0H
0xBE
All Pages ADC0 Data Word High Byte
page 571
ADC0L
0xBD
All Pages ADC0 Data Word Low Byte
page 571
ADC0LTH
0xC6
All Pages ADC0 Less-Than High Byte
page 601
ADC0LTL
0xC5
All Pages ADC0 Less-Than Low Byte
page 601
AMX0N
0xBA
All Pages AMUX0 Negative Channel Select
page 561
AMX0P
0xBB
All Pages AMUX0 Positive Channel Select
page 551
B
0xF0
All Pages B Register
page 105
CCH0CN
0x84
F
Cache Control
page 150
CCH0LC
0xD2
F
Cache Lock
page 152
CCH0MA
0xD3
F
Cache Miss Accumulator
page 153
CCH0TN
0xC9
F
Cache Tuning
page 151
CKCON
0x8E
All Pages Clock Control
page 255
CLKSEL
0x8F
CPT0CN
F
System Clock Select
page 175
0x9B
All Pages Comparator0 Control
page 74
CPT0MD
0x9D
All Pages Comparator0 Configuration
page 76
CPT0MX
0x9F
All Pages Comparator0 MUX Selection
page 75
CPT1CN
0x9A
All Pages Comparator1 Control
page 77
CPT1MD
0x9C
All Pages Comparator1 Configuration
page 79
CPT1MX
0x9E
All Pages Comparator1 MUX Selection
page 78
DPH
0x83
All Pages Data Pointer High Byte
page 103
DPL
0x82
All Pages Data Pointer Low Byte
page 103
EIE1
0xE6
All Pages Extended Interrupt Enable 1
page 113
EIE2
0xE7
All Pages Extended Interrupt Enable 2
page 115
EIP1
0xCE
F
Extended Interrupt Priority 1
page 114
EIP2
0xCF
F
Extended Interrupt Priority 2
page 115
Notes:
1. Refers to a register in the C8051F360/1/2/6/7/8/9 only.
2. Refers to a register in the C8051F360/3 only.
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Table 9.3. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
SFR
Page
Description
EMI0CF
0xC7
F
EMI0CN
0xAA
EMI0TC
0xF7
F
EMIF Timing Control
page 1622
FLKEY
0xB7
0
Flash Lock and Key
page 143
FLSCL
0xB6
0
Flash Scale
page 144
FLSTAT
0xAC
F
Flash Status
page 153
IDA0CN
0xB9
All Pages IDAC0 Control
page 661
IDA0H
0x97
All Pages IDAC0 High Byte
page 661
IDA0L
0x96
All Pages IDAC0 Low Byte
page 671
IE
0xA8
All Pages Interrupt Enable
page 111
IP
0xB8
All Pages Interrupt Priority
page 112
IT01CF
0xE4
All Pages INT0/INT1 Configuration
page 117
MAC0ACC0
0xD2
0
MAC0 Accumulator Byte 0 (LSB)
page 127
MAC0ACC1
0xD3
0
MAC0 Accumulator Byte 1
page 126
MAC0ACC2
0xD4
0
MAC0 Accumulator Byte 2
page 126
MAC0ACC3
0xD5
0
MAC0 Accumulator Byte 3 (MSB)
page 126
MAC0AH
0xA5
0
MAC0 A Register High Byte
page 124
MAC0AL
0xA4
0
MAC0 A Register Low Byte
page 125
MAC0BH
0xF2
0
MAC0 B Register High Byte
page 125
MAC0BL
0xF1
0
MAC0 B Register Low Byte
page 125
MAC0CF
0xD7
0
MAC0 Configuration
page 123
MAC0OVR
0xD6
0
MAC0 Accumulator Overflow
page 127
MAC0RNDH
0xAF
0
MAC0 Rounding Register High Byte
page 127
MAC0RNDL
0xAE
0
MAC0 Rounding Register Low Byte
page 128
MAC0STA
0xCF
0
MAC0 Status Register
page 124
OSCICL
0xBF
F
Internal Oscillator Calibration
page 171
OSCICN
0xB7
F
Internal Oscillator Control
page 172
OSCLCN
0xAD
F
Internal L-F Oscillator Control
page 173
OSCXCN
0xB6
F
External Oscillator Control
page 176
P0
0x80
P0MASK
0xF4
EMIF Configuration
page 1572
page 1562
All Pages EMIF Control
All Pages Port 0 Latch
0
Page No.
page 191
Port 0 Mask
page 193
Notes:
1. Refers to a register in the C8051F360/1/2/6/7/8/9 only.
2. Refers to a register in the C8051F360/3 only.
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Table 9.3. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
SFR
Page
Description
P0MAT
0xF3
0
Port 0 Match
page 193
P0MDIN
0xF1
F
Port 0 Input Mode
page 192
P0MDOUT
0xA4
F
Port 0 Output Mode Configuration
page 192
P0SKIP
0xD4
F
Port 0 Skip
page 193
P1
0x90
P1MASK
0xE2
0
Port 1 Mask
page 196
P1MAT
0xE1
0
Port 1 Match
page 195
P1MDIN
0xF2
F
Port 1 Input Mode
page 194
P1MDOUT
0xA5
F
Port 1 Output Mode Configuration
page 195
P1SKIP
0xD5
F
Port 1 Skip
page 195
P2
0xA0
P2MASK
0xB2
0
Port 2 Mask
page 198
P2MAT
0xB1
0
Port 2 Match
page 198
P2MDIN
0xF3
F
Port 2 Input Mode
page 197
P2MDOUT
0xA6
F
Port 2 Output Mode Configuration
page 197
P2SKIP
0xD6
F
Port 2 Skip
page 198
P3
0xB0
P3MDIN
0xF4
F
Port 3 Input Mode
page 199
P3MDOUT
0xAF
F
Port 3 Output Mode Configuration
page 200
P3SKIP
0xD7
F
Port 3 Skip
page 200
P4
0xB5
P4MDOUT
0xAE
PCA0CN
0xD8
All Pages PCA Control
page 277
PCA0CPH0
0xFC
All Pages PCA Module 0 Capture/Compare High Byte
page 281
PCA0CPH1
0xEA
All Pages PCA Module 1 Capture/Compare High Byte
page 281
PCA0CPH2
0xEC
All Pages PCA Module 2 Capture/Compare High Byte
page 281
PCA0CPH3
0xEE
All Pages PCA Module 3 Capture/Compare High Byte
page 281
PCA0CPH4
0xFE
All Pages PCA Module 4 Capture/Compare High Byte
page 281
PCA0CPH5
0xF6
All Pages PCA Module 5 Capture/Compare High Byte
page 281
PCA0CPL0
0xFB
All Pages PCA Module 0 Capture/Compare Low Byte
page 280
PCA0CPL1
0xE9
All Pages PCA Module 1 Capture/Compare Low Byte
page 280
All Pages Port 1 Latch
All Pages Port 2 Latch
All Pages Port 3 Latch
All Pages Port 4 Latch
F
Port 4 Output Mode Configuration
Notes:
1. Refers to a register in the C8051F360/1/2/6/7/8/9 only.
2. Refers to a register in the C8051F360/3 only.
100
Rev. 1.2
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page 194
page 196
page 199
page 201
page 201
C8051F360/1/2/3/4/5/6/7/8/9
Table 9.3. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
SFR
Page
PCA0CPL2
0xEB
All Pages PCA Module 2 Capture/Compare Low Byte
page 280
PCA0CPL3
0xED
All Pages PCA Module 3 Capture/Compare Low Byte
page 280
PCA0CPL4
0xFD
All Pages PCA Module 4 Capture/Compare Low Byte
page 280
PCA0CPL5
0xF5
All Pages PCA Module 5 Capture/Compare Low Byte
page 280
PCA0CPM0
0xDA
All Pages PCA Module 0 Mode
page 279
PCA0CPM1
0xDB
All Pages PCA Module 1 Mode
page 279
PCA0CPM2
0xDC
All Pages PCA Module 2 Mode
page 279
PCA0CPM3
0xDD
All Pages PCA Module 3 Mode
page 279
PCA0CPM4
0xDE
All Pages PCA Module 4 Mode
page 279
PCA0CPM5
0xDF
All Pages PCA Module 5 Mode
page 279
PCA0H
0xFA
All Pages PCA Counter High Byte
page 280
PCA0L
0xF9
All Pages PCA Counter Low Byte
page 280
PCA0MD
0xD9
All Pages PCA Mode
page 278
PCON
0x87
All Pages Power Control
page 107
PLL0CN
0xB3
F
PLL Control
page 181
PLL0DIV
0xA9
F
PLL Divider
page 181
PLL0FLT
0xB2
F
PLL Filter
page 182
PLL0MUL
0xB1
F
PLL Multiplier
page 182
PSCTL
0x8F
0
Flash Write/Erase Control
page 143
PSW
0xD0
All Pages Program Status Word
page 104
REF0CN
0xD1
All Pages Voltage Reference Control
page 691
RSTSRC
0xEF
All Pages Reset Source
page 134
SBUF0
0x99
All Pages UART 0 Data Buffer
page 227
SCON0
0x98
All Pages UART 0 Control
page 226
SFR0CN
0xE5
SFRLAST
0x86
All Pages SFR Stack Last Page
page 96
SFRNEXT
0x85
All Pages SFR Stack Next Page
page 96
SFRPAGE
0xA7
All Pages SFR Page Select
page 95
SMB0CF
0xC1
All Pages SMBus Configuration
page 209
SMB0CN
0xC0
All Pages SMBus Control
page 211
SMB0DAT
0xC2
All Pages SMBus Data
page 213
F
Description
SFR Page Control
Page No.
page 95
Notes:
1. Refers to a register in the C8051F360/1/2/6/7/8/9 only.
2. Refers to a register in the C8051F360/3 only.
Rev. 1.2
101
C8051F360/1/2/3/4/5/6/7/8/9
Table 9.3. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
SFR
Page
Description
Page No.
SP
0x81
All Pages Stack Pointer
page 103
SPI0CFG
0xA1
All Pages SPI Configuration
page 242
SPI0CKR
0xA2
All Pages SPI Clock Rate Control
page 244
SPI0CN
0xF8
All Pages SPI Control
page 243
SPI0DAT
0xA3
All Pages SPI Data
page 244
TCON
0x88
All Pages Timer/Counter Control
page 253
TH0
0x8C
All Pages Timer/Counter 0 High Byte
page 256
TH1
0x8D
All Pages Timer/Counter 1 High Byte
page 256
TL0
0x8A
All Pages Timer/Counter 0 Low Byte
page 256
TL1
0x8B
All Pages Timer/Counter 1 Low Byte
page 256
TMOD
0x89
All Pages Timer/Counter Mode
page 254
TMR2CN
0xC8
All Pages Timer/Counter 2 Control
page 259
TMR2H
0xCD
All Pages Timer/Counter 2 High Byte
page 260
TMR2L
0xCC
All Pages Timer/Counter 2 Low Byte
page 260
TMR2RLH
0xCB
All Pages Timer 2 Reload Register High Byte
page 260
TMR2RLL
0xCA
All Pages Timer 2 Reload Register Low Byte
page 260
TMR3CN
0x91
All Pages Timer 3 Control
page 263
TMR3H
0x95
All Pages Timer 3 High Byte
page 264
TMR3L
0x94
All Pages Timer 3 Low Byte
page 264
TMR3RLH
0x93
All Pages Timer 3 Reload Register High Byte
page 264
TMR3RLL
0x92
All Pages Timer 3 Reload Register Low Byte
page 264
VDM0CN
0xFF
page 132
XBR0
0xE1
All Pages VDD Monitor Control
F
Port I/O Crossbar Control 0
XBR1
0xE2
F
Port I/O Crossbar Control 1
Notes:
1. Refers to a register in the C8051F360/1/2/6/7/8/9 only.
2. Refers to a register in the C8051F360/3 only.
102
Rev. 1.2
page 189
page 190
C8051F360/1/2/3/4/5/6/7/8/9
9.4.7. Register Descriptions
Following are descriptions of SFRs related to the operation of the CIP-51 System Controller. Reserved bits
should not be set to logic ‘1’. Future product versions may use these bits to implement new features in
which case the reset value of the bit will be logic ‘0’, selecting the feature's default state. Detailed descriptions of the remaining SFRs are included in the sections of the data sheet associated with their corresponding system function.
SFR Definition 9.5. SP: Stack Pointer
SFR Page:
all pages
SFR Address: 0x81
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000111
Bits 7–0: SP: Stack Pointer.
The Stack Pointer holds the location of the top of the stack. The stack pointer is incremented
before every PUSH operation. The SP register defaults to 0x07 after reset.
SFR Definition 9.6. DPL: Data Pointer Low Byte
SFR Page
all pages
SFR Address: 0x82
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: DPL: Data Pointer Low.
The DPL register is the low byte of the 16-bit DPTR. DPTR is used to access indirectly
addressed XRAM and Flash memory.
SFR Definition 9.7. DPH: Data Pointer High Byte
SFR Page:
all pages
SFR Address: 0x83
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: DPH: Data Pointer High.
The DPH register is the high byte of the 16-bit DPTR. DPTR is used to access indirectly
addressed XRAM and Flash memory.
Rev. 1.2
103
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 9.8. PSW: Program Status Word
SFR Page:
all pages
SFR Address: 0xD0
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
Reset Value
CY
AC
F0
RS1
RS0
OV
F1
PARITY
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
CY: Carry Flag.
This bit is set when the last arithmetic operation resulted in a carry (addition) or a borrow
(subtraction). It is cleared to 0 by all other arithmetic operations.
Bit 6:
AC: Auxiliary Carry Flag
This bit is set when the last arithmetic operation resulted in a carry into (addition) or a borrow
from (subtraction) the high order nibble. It is cleared to 0 by all other arithmetic operations.
Bit 5:
F0: User Flag 0.
This is a bit-addressable, general purpose flag for use under software control.
Bits 4–3: RS1–RS0: Register Bank Select.
These bits select which register bank is used during register accesses.
Bit 2:
Bit 1:
Bit 0:
104
RS1
RS0
Register Bank
Address
0
0
0
0x00–0x07
0
1
1
0x08–0x0F
1
0
2
0x10–0x17
1
1
3
0x18–0x1F
OV: Overflow Flag.
This bit is set to 1 under the following circumstances:
• An ADD, ADDC, or SUBB instruction causes a sign-change overflow.
• A MUL instruction results in an overflow (result is greater than 255).
• A DIV instruction causes a divide-by-zero condition.
The OV bit is cleared to 0 by the ADD, ADDC, SUBB, MUL, and DIV instructions in all other
cases.
F1: User Flag 1.
This is a bit-addressable, general purpose flag for use under software control.
PARITY: Parity Flag.
This bit is set to 1 if the sum of the eight bits in the accumulator is odd and cleared if the sum
is even.
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 9.9. ACC: Accumulator
SFR Page:
all pages
SFR Address: 0xE0
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
ACC.7
ACC.6
ACC.5
ACC.4
ACC.3
ACC.2
ACC.1
ACC.0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: ACC: Accumulator.
This register is the accumulator for arithmetic operations.
SFR Definition 9.10. B: B Register
SFR Page:
all pages
SFR Address: 0xF0
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
B.7
B.6
B.5
B.4
B.3
B.2
B.1
B.0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: B: B Register.
This register serves as a second accumulator for certain arithmetic operations.
9.5.
Power Management Modes
The CIP-51 core has two software programmable power management modes: Idle and Stop. Idle mode
halts the CPU while leaving the external peripherals and internal clocks active. In Stop mode, the CPU is
halted, all interrupts and timers (except the Missing Clock Detector) are inactive, and the system clock is
stopped. Since clocks are running in Idle mode, power consumption is dependent upon the system clock
frequency and the number of peripherals left in active mode before entering Idle. Stop mode consumes the
least power. SFR Definition 9.11 describes the Power Control Register (PCON) used to control the CIP51's power management modes.
Although the CIP-51 has Idle and Stop modes built in (as with any standard 8051 architecture), power
management of the entire MCU is better accomplished by enabling/disabling individual peripherals as
needed. Each analog peripheral can be disabled when not in use and put into low power mode. Digital
peripherals, such as timers or serial buses, draw little power whenever they are not in use. Turning off the
Flash memory saves power, similar to entering Idle mode. Turning off the oscillator saves even more
power, but requires a reset to restart the MCU.
The C8051F36x devices feature an additional low-power SUSPEND mode, which stops the internal oscillator until an awakening event occurs. See Section “16.1.1. Internal Oscillator Suspend Mode” on
page 171 for more information.
Rev. 1.2
105
C8051F360/1/2/3/4/5/6/7/8/9
9.5.1. Idle Mode
Setting the Idle Mode Select bit (PCON.0) causes the CIP-51 to halt the CPU and enter Idle mode as soon
as the instruction that sets the bit completes. All internal registers and memory maintain their original
data. All analog and digital peripherals can remain active during Idle mode.
Idle mode is terminated when an enabled interrupt or RST is asserted. The assertion of an enabled interrupt will cause the Idle Mode Selection bit (PCON.0) to be cleared and the CPU to resume operation. The
pending interrupt will be serviced and the next instruction to be executed after the return from interrupt
(RETI) will be the instruction immediately following the one that set the Idle Mode Select bit. If Idle mode is
terminated by an internal or external reset, the CIP-51 performs a normal reset sequence and begins program execution at address 0x0000.
If enabled, the WDT will eventually cause an internal watchdog reset and thereby terminate the Idle mode.
This feature protects the system from an unintended permanent shutdown in the event of an inadvertent
write to the PCON register. If this behavior is not desired, the WDT may be disabled by software prior to
entering the Idle mode if the WDT was initially configured to allow this operation. This provides the opportunity for additional power savings, allowing the system to remain in the Idle mode indefinitely, waiting for
an external stimulus to wake up the system. Refer to Section 22.3 for more information on the use and
configuration of the WDT.
Note: Any instruction which sets the IDLE bit should be immediately followed by an instruction which has
two or more opcode bytes. For example:
// in ‘C’:
PCON |= 0x01;
PCON = PCON;
// Set IDLE bit
// ... Followed by a 3-cycle Dummy Instruction
; in assembly:
ORL PCON, #01h
MOV PCON, PCON
; Set IDLE bit
; ... Followed by a 3-cycle Dummy Instruction
If the instruction following the write to the IDLE bit is a single-byte instruction and an interrupt occurs during
the execution of the instruction of the instruction which sets the IDLE bit, the CPU may not wake from IDLE
mode when a future interrupt occurs.
9.5.2. Stop Mode
Setting the Stop Mode Select bit (PCON.1) causes the CIP-51 to enter Stop mode as soon as the instruction that sets the bit completes. In Stop mode, the CPU and oscillators are stopped, effectively shutting
down all digital peripherals. Each analog peripheral must be shut down individually prior to entering Stop
Mode. Stop mode can only be terminated by an internal or external reset. On reset, the CIP-51 performs
the normal reset sequence and begins program execution at address 0x0000.
If enabled, the Missing Clock Detector will cause an internal reset and thereby terminate the Stop mode.
The Missing Clock Detector should be disabled if the CPU is to be put to sleep for longer than the MCD
timeout of 100 µs.
9.5.3. Suspend Mode
The C8051F36x devices feature a low-power SUSPEND mode, which stops the internal oscillator until an
awakening event occurs. See Section “16.1.1. Internal Oscillator Suspend Mode” on page 171.
106
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 9.11. PCON: Power Control
SFR Page:
all pages
SFR Address: 0x87
R/W
R/W
R/W
R/W
R/W
R/W
Reserved Reserved Reserved Reserved Reserved Reserved
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
R/W
R/W
Reset Value
STOP
IDLE
00000000
Bit1
Bit0
Bits 7–3: RESERVED. Read = 000000b. Must Write 000000b.
Bit 1:
STOP: STOP Mode Select.
Writing a ‘1’ to this bit will place the CIP-51 into STOP mode. This bit will always read ‘0’.
1: CIP-51 forced into power-down mode. (Turns off oscillator).
Bit 0:
IDLE: IDLE Mode Select.
Writing a ‘1’ to this bit will place the CIP-51 into IDLE mode. This bit will always read ‘0’.
1: CIP-51 forced into IDLE mode. (Shuts off clock to CPU, but clock to Timers, Interrupts,
and all peripherals remain active.)
Rev. 1.2
107
C8051F360/1/2/3/4/5/6/7/8/9
10. Interrupt Handler
The C8051F36x family includes an extended interrupt system supporting a total of 16 interrupt sources
with two priority levels. The allocation of interrupt sources between on-chip peripherals and external input
pins varies according to the specific version of the device. Each interrupt source has one or more associated interrupt-pending flag(s) located in an SFR. When a peripheral or external source meets a valid interrupt condition, the associated interrupt-pending flag is set to logic ‘1’.
If interrupts are enabled for the source, an interrupt request is generated when the interrupt-pending flag is
set. As soon as execution of the current instruction is complete, the CPU generates an LCALL to a predetermined address to begin execution of an interrupt service routine (ISR). Each ISR must end with an RETI
instruction, which returns program execution to the next instruction that would have been executed if the
interrupt request had not occurred. If interrupts are not enabled, the interrupt-pending flag is ignored by the
hardware and program execution continues as normal. (The interrupt-pending flag is set to logic ‘1’ regardless of the interrupt's enable/disable state.)
Each interrupt source can be individually enabled or disabled through the use of an associated interrupt
enable bit in the Interrupt Enable and Extended Interrupt Enable SFRs. However, interrupts must first be
globally enabled by setting the EA bit (IE.7) to logic ‘1’ before the individual interrupt enables are recognized. Setting the EA bit to logic ‘0’ disables all interrupt sources regardless of the individual interruptenable settings. Note that interrupts which occur when the EA bit is set to logic ‘0’ will be held in a pending
state, and will not be serviced until the EA bit is set back to logic ‘1’.
Note: Any instruction that clears a bit to disable an interrupt should be immediately followed by an instruction that has two or more opcode bytes. Using EA (global interrupt enable) as an example:
// in 'C':
EA = 0; // clear EA bit.
EA = 0; // this is a dummy instruction with two-byte opcode.
; in assembly:
CLR EA ; clear EA bit.
CLR EA ; this is a dummy instruction with two-byte opcode.
For example, if an interrupt is posted during the execution phase of a "CLR EA" opcode (or any instruction
which clears a bit to disable an interrupt source), and the instruction is followed by a single-cycle instruction, the interrupt may be taken. However, a read of the enable bit will return a '0' inside the interrupt service routine. When the bit-clearing opcode is followed by a multi-cycle instruction, the interrupt will not be
taken.
Some interrupt-pending flags are automatically cleared by the hardware when the CPU vectors to the ISR.
However, most are not cleared by the hardware and must be cleared by software before returning from the
ISR. If an interrupt-pending flag remains set after the CPU completes the return-from-interrupt (RETI)
instruction, a new interrupt request will be generated immediately and the CPU will re-enter the ISR after
the completion of the next instruction.
10.1. MCU Interrupt Sources and Vectors
The C8051F36x MCUs support 16 interrupt sources. Software can simulate an interrupt by setting any
interrupt-pending flag to logic ‘1’. If interrupts are enabled for the flag, an interrupt request will be generated and the CPU will vector to the ISR address associated with the interrupt-pending flag. MCU interrupt
sources, associated vector addresses, priority order, and control bits are summarized in Table 10.1 on
page 109. Refer to the data sheet section associated with a particular on-chip peripheral for information
regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s).
108
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
10.2. Interrupt Priorities
Each interrupt source can be individually programmed to one of two priority levels: low or high. A low priority interrupt service routine can be preempted by a high priority interrupt. A high priority interrupt cannot be
preempted. Each interrupt has an associated interrupt priority bit in an SFR (IP, EIP1, or EIP2) used to
configure its priority level. Low priority is the default. If two interrupts are recognized simultaneously, the
interrupt with the higher priority is serviced first. If both interrupts have the same priority level, a fixed priority order is used to arbitrate, given in Table 10.1.
10.3. Interrupt Latency
Interrupt response time depends on the state of the CPU when the interrupt occurs. Pending interrupts are
sampled and priority decoded each system clock cycle. Therefore, the fastest possible response time is
5 system clock cycles: 1 clock cycle to detect the interrupt and 4 clock cycles to complete the LCALL to the
ISR. Additional clock cycles will be required if a cache miss occurs (see Section 14 for more details). If an
interrupt is pending when a RETI is executed, a single instruction is executed before an LCALL is made to
service the pending interrupt. Therefore, the maximum response time for an interrupt (when no other interrupt is currently being serviced or the new interrupt is of greater priority) is when the CPU is performing an
RETI instruction followed by a DIV as the next instruction, and a cache miss event also occurs. If the CPU
is executing an ISR for an interrupt with equal or higher priority, the new interrupt will not be serviced until
the current ISR completes, including the RETI and following instruction.
Interrupt Priority
Pending Flag
Vector
Order
Enable
Flag
Priority
Control
IE0 (TCON.1)
TF0 (TCON.5)
IE1 (TCON.3)
TF1 (TCON.7)
RI0 (SCON0.0)
TI0 (SCON0.1)
TF2H (TMR2CN.7)
TF2L (TMR2CN.6)
SPIF (SPI0CN.7)
WCOL (SPI0CN.6)
MODF (SPI0CN.5)
RXOVRN (SPI0CN.4)
Y
Y
Y
Y
Y
Y
Y
Y
Always
Always
Enabled
Highest
EX0 (IE.0) PX0 (IP.0)
ET0 (IE.1) PT0 (IP.1)
EX1 (IE.2) PX1 (IP.2)
ET1 (IE.3) PT1 (IP.3)
Y
N
ES0 (IE.4) PS0 (IP.4)
Y
N
ET2 (IE.5)
PT2 (IP.5)
Y
N
ESPI0
(IE.6)
PSPI0
(IP.6)
7
SI (SMB0CN.0)
Y
N
0x0043
8
0x004B
9
N/A
AD0WINT
(ADC0CN.5)
0x0053
10
ESMB0
(EIE1.0)
N/A
EWADC0
(EIE1.2)
EADC0
(EIE1.3)
PSMB0
(EIP1.0)
N/A
PWADC0
(EIP1.2)
PADC0
(EIP1.3)
Reset
0x0000
Top
External Interrupt 0 (/INT0)
Timer 0 Overflow
External Interrupt 1 (/INT1)
Timer 1 Overflow
0x0003
0x000B
0x0013
0x001B
0
1
2
3
UART0
0x0023
4
Timer 2 Overflow
0x002B
5
SPI0
0x0033
6
SMB0
0x003B
RESERVED
ADC0 Window
Comparator
ADC0 End of Conversion
Cleared by HW?
Interrupt Source
Bit addressable?
Table 10.1. Interrupt Summary
None
AD0INT (ADC0STA.5)
Rev. 1.2
N/A N/A
N/A N/A
Y
N
Y
N
109
C8051F360/1/2/3/4/5/6/7/8/9
Interrupt Priority
Pending Flag
Vector
Order
Programmable Counter
Array
0x005B
11
Comparator0
0x0063
12
Comparator1
0x006B
13
Timer 3 Overflow
0x0073
14
RESERVED
0x007B
Port Match
0x0083
Cleared by HW?
Interrupt Source
Bit addressable?
Table 10.1. Interrupt Summary (Continued)
Y
N
N
N
N
N
N
N
15
CF (PCA0CN.7)
CCFn (PCA0CN.n)
CP0FIF (CPT0CN.4)
CP0RIF (CPT0CN.5)
CP1FIF (CPT1CN.4)
CP1RIF (CPT1CN.5)
TF3H (TMR3CN.7)
TF3L (TMR3CN.6)
N/A
N/A N/A
16
N/A
N/A N/A
Enable
Flag
EPCA0
(EIE1.4)
ECP0
(EIE1.5)
ECP1
(EIE1.6)
ET3
(EIE1.7)
N/A
EMAT
(EIE2.1)
Priority
Control
PPCA0
(EIP1.4)
PCP0
(EIP1.5)
PCP1
(EIP1.6)
PT3
(EIP1.7)
N/A
PMAT
(EIP2.1)
10.4. Interrupt Register Descriptions
The SFRs used to enable the interrupt sources and set their priority level are described below. Refer to the
data sheet section associated with a particular on-chip peripheral for information regarding valid interrupt
conditions for the peripheral and the behavior of its interrupt-pending flag(s).
110
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SFR Definition 10.1. IE: Interrupt Enable
SFR Page:
all pages
SFR Address: 0xA8
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
EA
ESPI0
ET2
ES0
ET1
EX1
ET0
EX0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
EA: Global Interrupt Enable.
This bit globally enables/disables all interrupts. It overrides the individual interrupt mask settings.
0: Disable all interrupt sources.
1: Enable each interrupt according to its individual mask setting.
ESPI0: Enable Serial Peripheral Interface (SPI0) Interrupt.
This bit sets the masking of the SPI0 interrupts.
0: Disable all SPI0 interrupts.
1: Enable interrupt requests generated by SPI0.
ET2: Enable Timer 2 Interrupt.
This bit sets the masking of the Timer 2 interrupt.
0: Disable Timer 2 interrupt.
1: Enable interrupt requests generated by the TF2L or TF2H flags.
ES0: Enable UART0 Interrupt.
This bit sets the masking of the UART0 interrupt.
0: Disable UART0 interrupt.
1: Enable UART0 interrupt.
ET1: Enable Timer 1 Interrupt.
This bit sets the masking of the Timer 1 interrupt.
0: Disable all Timer 1 interrupt.
1: Enable interrupt requests generated by the TF1 flag.
EX1: Enable External Interrupt 1.
This bit sets the masking of External Interrupt 1.
0: Disable external interrupt 1.
1: Enable interrupt requests generated by the /INT1 input.
ET0: Enable Timer 0 Interrupt.
This bit sets the masking of the Timer 0 interrupt.
0: Disable all Timer 0 interrupt.
1: Enable interrupt requests generated by the TF0 flag.
EX0: Enable External Interrupt 0.
This bit sets the masking of External Interrupt 0.
0: Disable external interrupt 0.
1: Enable interrupt requests generated by the /INT0 input.
Rev. 1.2
111
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SFR Definition 10.2. IP: Interrupt Priority
SFR Page:
all pages
SFR Address: 0xB8
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
–
PSPI0
PT2
PS0
PT1
PX1
PT0
PX0
10000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
112
(bit addressable)
UNUSED. Read = 1b, Write = don't care.
PSPI0: Serial Peripheral Interface (SPI0) Interrupt Priority Control.
This bit sets the priority of the SPI0 interrupt.
0: SPI0 interrupt set to low priority level.
1: SPI0 interrupt set to high priority level.
PT2: Timer 2 Interrupt Priority Control.
This bit sets the priority of the Timer 2 interrupt.
0: Timer 2 interrupt set to low priority level.
1: Timer 2 interrupt set to high priority level.
PS0: UART0 Interrupt Priority Control.
This bit sets the priority of the UART0 interrupt.
0: UART0 interrupt set to low priority level.
1: UART0 interrupt set to high priority level.
PT1: Timer 1 Interrupt Priority Control.
This bit sets the priority of the Timer 1 interrupt.
0: Timer 1 interrupt set to low priority level.
1: Timer 1 interrupt set to high priority level.
PX1: External Interrupt 1 Priority Control.
This bit sets the priority of the External Interrupt 1 interrupt.
0: External Interrupt 1 set to low priority level.
1: External Interrupt 1 set to high priority level.
PT0: Timer 0 Interrupt Priority Control.
This bit sets the priority of the Timer 0 interrupt.
0: Timer 0 interrupt set to low priority level.
1: Timer 0 interrupt set to high priority level.
PX0: External Interrupt 0 Priority Control.
This bit sets the priority of the External Interrupt 0 interrupt.
0: External Interrupt 0 set to low priority level.
1: External Interrupt 0 set to high priority level.
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 10.3. EIE1: Extended Interrupt Enable 1
SFR Page:
all pages
SFR Address: 0xE6
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
ET3
ECP1
ECP0
EPCA0
EADC0
EWADC0
–
ESMB0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
ET3: Enable Timer 3 Interrupt.
This bit sets the masking of the Timer 3 interrupt.
0: Disable Timer 3 interrupts.
1: Enable interrupt requests generated by the TF3L or TF3H flags.
ECP1: Enable Comparator1 (CP1) Interrupt.
This bit sets the masking of the CP1 interrupt.
0: Disable CP1 interrupts.
1: Enable interrupt requests generated by the CP1RIF or CP1FIF flags.
ECP0: Enable Comparator0 (CP0) Interrupt.
This bit sets the masking of the CP0 interrupt.
0: Disable CP0 interrupts.
1: Enable interrupt requests generated by the CP0RIF or CP0FIF flags.
EPCA0: Enable Programmable Counter Array (PCA0) Interrupt.
This bit sets the masking of the PCA0 interrupts.
0: Disable all PCA0 interrupts.
1: Enable interrupt requests generated by PCA0.
EADC0: Enable ADC0 Conversion Complete Interrupt.
This bit sets the masking of the ADC0 Conversion Complete interrupt.
0: Disable ADC0 Conversion Complete interrupt.
1: Enable interrupt requests generated by the AD0INT flag.
EWADC0: Enable ADC0 Window Comparison Interrupt.
This bit sets the masking of the ADC0 Window Comparison interrupt.
0: Disable ADC0 Window Comparison interrupt.
1: Enable interrupt requests generated by the AD0WINT flag.
UNUSED. Read = 0b. Write = don’t care.
ESMB0: Enable SMBus (SMB0) Interrupt.
This bit sets the masking of the SMB0 interrupt.
0: Disable all SMB0 interrupts.
1: Enable interrupt requests generated by SMB0.
Rev. 1.2
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SFR Definition 10.4. EIP1: Extended Interrupt Priority 1
SFR Page:
F
SFR Address: 0xCE
R/W
R/W
R/W
R/W
R/W
R/W
PT3
PCP1
PCP0
PPCA0
PADC0
Bit7
Bit6
Bit5
Bit4
Bit3
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
114
R/W
R/W
Reset Value
PWADC0
–
PSMB0
00000000
Bit2
Bit1
Bit0
PT3: Timer 3 Interrupt Priority Control.
This bit sets the priority of the Timer 3 interrupt.
0: Timer 3 interrupts set to low priority level.
1: Timer 3 interrupts set to high priority level.
PCP1: Comparator1 (CP1) Interrupt Priority Control.
This bit sets the priority of the CP1 interrupt.
0: CP1 interrupt set to low priority level.
1: CP1 interrupt set to high priority level.
PCP0: Comparator0 (CP0) Interrupt Priority Control.
This bit sets the priority of the CP0 interrupt.
0: CP0 interrupt set to low priority level.
1: CP0 interrupt set to high priority level.
PPCA0: Programmable Counter Array (PCA0) Interrupt Priority Control.
This bit sets the priority of the PCA0 interrupt.
0: PCA0 interrupt set to low priority level.
1: PCA0 interrupt set to high priority level.
PADC0: ADC0 Conversion Complete Interrupt Priority Control.
This bit sets the priority of the ADC0 Conversion Complete interrupt.
0: ADC0 Conversion Complete interrupt set to low priority level.
1: ADC0 Conversion Complete interrupt set to high priority level.
PWADC0: ADC0 Window Comparison Interrupt Priority Control.
This bit sets the priority of the ADC0 Window Comparison interrupt.
0: ADC0 Window Comparison interrupt set to low priority level.
1: ADC0 Window Comparison interrupt set to high priority level.
UNUSED. Read = 0b. Write = don’t care.
PSMB0: SMBus (SMB0) Interrupt Priority Control.
This bit sets the priority of the SMB0 interrupt.
0: SMB0 interrupt set to low priority level.
1: SMB0 interrupt set to high priority level.
Rev. 1.2
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SFR Definition 10.5. EIE2: Extended Interrupt Enable 2
SFR Page:
all pages
SFR Address: 0xE7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
–
–
–
–
–
–
EMAT
–
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–2: UNUSED. Read = 000000b. Write = don’t care.
Bit 1:
EMAT: Enable Port Match Interrupt.
This bit sets the masking of the Port Match interrupt.
0: Disable the Port Match interrupt.
1: Enable the Port Match interrupt.
Bit 0:
UNUSED. Read = 0b. Write = don’t care.
SFR Definition 10.6. EIP2: Extended Interrupt Priority 2
SFR Page:
F
SFR Address: 0xCF
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
–
–
–
–
–
–
PMAT
–
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–2: UNUSED. Read = 000000b. Write = don’t care.
Bit 1:
PMAT: Port Match Interrupt Priority Control.
This bit sets the priority of the Port Match interrupt.
0: Port Match interrupt set to low priority level.
1: Port Match interrupt set to high priority level.
Bit 0:
UNUSED. Read = 0b. Write = don’t care.
Rev. 1.2
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10.5. External Interrupts
The /INT0 and /INT1 external interrupt sources are configurable as active high or low, edge or level sensitive. The IN0PL (/INT0 Polarity) and IN1PL (/INT1 Polarity) bits in the IT01CF register select active high or
active low; the IT0 and IT1 bits in TCON (Section “21.1. Timer 0 and Timer 1” on page 249) select level or
edge sensitive. The table below lists the possible configurations.
IT0
1
1
0
0
IN0PL
0
1
0
1
/INT0 Interrupt
Active low, edge sensitive
Active high, edge sensitive
Active low, level sensitive
Active high, level sensitive
IT1
1
1
0
0
IN1PL
0
1
0
1
/INT1 Interrupt
Active low, edge sensitive
Active high, edge sensitive
Active low, level sensitive
Active high, level sensitive
/INT0 and /INT1 are assigned to Port pins as defined in the IT01CF register (see SFR Definition 10.7).
Note that /INT0 and /INT0 Port pin assignments are independent of any Crossbar assignments. /INT0 and
/INT1 will monitor their assigned Port pins without disturbing the peripheral that was assigned the Port pin
via the Crossbar. To assign a Port pin only to /INT0 and/or /INT1, configure the Crossbar to skip the
selected pin(s). This is accomplished by setting the associated bit in register XBR0 (see Section
“17.1. Priority Crossbar Decoder” on page 186 for complete details on configuring the Crossbar).
IE0 (TCON.1) and IE1 (TCON.3) serve as the interrupt-pending flags for the /INT0 and /INT1 external
interrupts, respectively. If an /INT0 or /INT1 external interrupt is configured as edge-sensitive, the corresponding interrupt-pending flag is automatically cleared by the hardware when the CPU vectors to the ISR.
When configured as level sensitive, the interrupt-pending flag remains logic ‘1’ while the input is active as
defined by the corresponding polarity bit (IN0PL or IN1PL); the flag remains logic ‘0’ while the input is inactive. The external interrupt source must hold the input active until the interrupt request is recognized. It
must then deactivate the interrupt request before execution of the ISR completes or another interrupt
request will be generated.
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SFR Definition 10.7. IT01CF: INT0/INT1 Configuration
SFR Page:
all pages
SFR Address: 0xE4
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
IN1PL
IN1SL2
IN1SL1
IN1SL0
IN0PL
IN0SL2
IN0SL1
IN0SL0
00000001
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Note: Refer to SFR Definition 21.1. “TCON: Timer Control” on page 253 for INT0/1 edge- or level-sensitive interrupt selection.
Bit 7:
IN1PL: /INT1 Polarity
0: /INT1 input is active low.
1: /INT1 input is active high.
Bits 6–4: IN1SL2-0: /INT1 Port Pin Selection Bits
These bits select which Port pin is assigned to /INT1. Note that this pin assignment is independent of the Crossbar; /INT1 will monitor the assigned Port pin without disturbing the
peripheral that has been assigned the Port pin via the Crossbar. The Crossbar will not
assign the Port pin to a peripheral if it is configured to skip the selected pin (accomplished by
setting to ‘1’ the corresponding bit in register P0SKIP).
IN1SL2-0
000
001
010
011
100
101
110
111
/INT1 Port Pin
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
Bit 3:
IN0PL: /INT0 Polarity
0: /INT0 interrupt is active low.
1: /INT0 interrupt is active high.
Bits 2–0: INT0SL2-0: /INT0 Port Pin Selection Bits
These bits select which Port pin is assigned to /INT0. Note that this pin assignment is independent of the Crossbar. /INT0 will monitor the assigned Port pin without disturbing the
peripheral that has been assigned the Port pin via the Crossbar. The Crossbar will not
assign the Port pin to a peripheral if it is configured to skip the selected pin (accomplished by
setting to ‘1’ the corresponding bit in register P0SKIP).
IN0SL2-0
000
001
010
011
100
101
110
111
/INT0 Port Pin
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
Rev. 1.2
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11. Multiply And Accumulate (MAC0)
The C8051F36x devices include a multiply and accumulate engine which can be used to speed up many
mathematical operations. MAC0 contains a 16-by-16 bit multiplier and a 40-bit adder, which can perform
integer or fractional multiply-accumulate and multiply operations on signed input values in two SYSCLK
cycles. A rounding engine provides a rounded 16-bit fractional result after an additional (third) SYSCLK
cycle. MAC0 also contains a 1-bit arithmetic shifter that will left or right-shift the contents of the 40-bit accumulator in a single SYSCLK cycle. Figure 11.1 shows a block diagram of the MAC0 unit and its associated
Special Function Registers.
MAC0 A Register
MAC0AH MAC0AL
MAC0FM
MAC0 B Register
MAC0BH MAC0BL
MAC0MS
16 x 16 Multiply
1
0
0
40 bit Add
Rounding Engine
MAC0SC
MAC0SD
MAC0CA
MAC0SAT
MAC0FM
MAC0MS
1 bit Shift
MAC0 Rounding Register
MAC0RNDH MAC0RNDL
MAC0CF
MAC0ACC0
Flag Logic
MAC0HO
MAC0Z
MAC0SO
MAC0N
MAC0 Accumulator
MAC0ACC3 MAC0ACC2 MAC0ACC1
MAC0OVR
MAC0STA
Figure 11.1. MAC0 Block Diagram
11.1. Special Function Registers
There are thirteen Special Function Register (SFR) locations associated with MAC0. Two of these registers are related to configuration and operation, while the other eleven are used to store multi-byte input
and output data for MAC0. The Configuration register MAC0CF (SFR Definition 11.1) is used to configure
and control MAC0. The Status register MAC0STA (SFR Definition 11.2) contains flags to indicate overflow
conditions, as well as zero and negative results. The 16-bit MAC0A (MAC0AH:MAC0AL) and MAC0B
(MAC0BH:MAC0BL) registers are used as inputs to the multiplier. The MAC0 Accumulator register is 40
bits long, and consists of five SFRs: MAC0OVR, MAC0ACC3, MAC0ACC2, MAC0ACC1, and
MAC0ACC0. The primary results of a MAC0 operation are stored in the Accumulator registers. If they are
needed, the rounded results are stored in the 16-bit Rounding Register MAC0RND
(MAC0RNDH:MAC0RNDL).
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11.2. Integer and Fractional Math
MAC0 is capable of interpreting the 16-bit inputs stored in MAC0A and MAC0B as signed integers or as
signed fractional numbers. When the MAC0FM bit (MAC0CF.1) is cleared to ‘0’, the inputs are treated as
16-bit, 2’s complement, integer values. After the operation, the accumulator will contain a 40-bit, 2’s complement, integer value. Figure 11.2 shows how integers are stored in the SFRs.
MAC0A and MAC0B Bit Weighting
High Byte
-(215)
214
213
212
Low Byte
211
210
29
28
27
26
25
24
23
22
21
20
MAC0 Accumulator Bit Weighting
MAC0OVR
-(239)
238
MAC0ACC3 : MAC0ACC2 : MAC0ACC1 : MAC0ACC0
233
232
231
230
229
228
24
23
22
21
20
Figure 11.2. Integer Mode Data Representation
When the MAC0FM bit is set to ‘1’, the inputs are treated at 16-bit, 2’s complement, fractional values. The
decimal point is located between bits 15 and 14 of the data word. After the operation, the accumulator will
contain a 40-bit, 2’s complement, fractional value, with the decimal point located between bits 31 and 30.
Figure 11.3 shows how fractional numbers are stored in the SFRs.
MAC0A, and MAC0B Bit Weighting
High Byte
-1
2-1
2-2
2-3
Low Byte
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
MAC0 Accumulator Bit Weighting
MAC0OVR
-(28)
27
MAC0ACC3 : MAC0ACC2 : MAC0ACC1 : MAC0ACC0
22
21
20
2-1
2-2
2-3
2-27
2-28
2-29
2-30
2-31
MAC0RND Bit Weighting
High Byte
* -2
1
2-1
2-2
2-3
2-4
Low Byte
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
* The MAC0RND register contains the 16 LSBs of a two's complement number. The MAC0N Flag can be
used to determine the sign of the MAC0RND register.
Figure 11.3. Fractional Mode Data Representation
Rev. 1.2
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11.3. Operating in Multiply and Accumulate Mode
MAC0 operates in Multiply and Accumulate (MAC) mode when the MAC0MS bit (MAC0CF.0) is cleared to
‘0’. When operating in MAC mode, MAC0 performs a 16-by-16 bit multiply on the contents of the MAC0A
and MAC0B registers, and adds the result to the contents of the 40-bit MAC0 accumulator. Figure 11.4
shows the MAC0 pipeline. There are three stages in the pipeline, each of which takes exactly one SYSCLK
cycle to complete. The MAC operation is initiated with a write to the MAC0BL register. After the MAC0BL
register is written, MAC0A and MAC0B are multiplied on the first SYSCLK cycle. During the second stage
of the MAC0 pipeline, the results of the multiplication are added to the current accumulator contents, and
the result of the addition is stored in the MAC0 accumulator. The status flags in the MAC0STA register are
set after the end of the second pipeline stage. During the second stage of the pipeline, the next multiplication can be initiated by writing to the MAC0BL register, if it is desired. The rounded (and optionally, saturated) result is available in the MAC0RNDH and MAC0RNDL registers at the end of the third pipeline
stage. If the MAC0CA bit (MAC0CF.3) is set to ‘1’ when the MAC operation is initiated, the accumulator
and all MAC0STA flags will be cleared during the next cycle of the controller’s clock (SYSCLK). The
MAC0CA bit will clear itself to ‘0’ when the clear operation is complete.
MAC0 Operation
Begins
Write
MAC0BL
Multiply
Accumulator
Results Available
Add
Round
Write
MAC0BL
Multiply
Rounded Results
Available
Add
Round
Next MAC0
Operation May
Be Initiated
Here
Figure 11.4. MAC0 Pipeline
11.4. Operating in Multiply Only Mode
MAC0 operates in Multiply Only mode when the MAC0MS bit (MAC0CF.0) is set to ‘1’. Multiply Only mode
is identical to Multiply and Accumulate mode, except that the multiplication result is added with a value of
zero before being stored in the MAC0 accumulator (i.e. it overwrites the current accumulator contents).
The result of the multiplication is available in the MAC0 accumulator registers at the end of the second
MAC0 pipeline stage (two SYSCLKs after writing to MAC0BL). As in MAC mode, the rounded result is
available in the MAC0 Rounding Registers after the third pipeline stage. Note that in Multiply Only mode,
the MAC0HO flag is not affected.
11.5. Accumulator Shift Operations
MAC0 contains a 1-bit arithmetic shift function which can be used to shift the contents of the 40-bit accumulator left or right by one bit. The accumulator shift is initiated by writing a ‘1’ to the MAC0SC bit
(MAC0CF.5), and takes one SYSCLK cycle (the rounded result is available in the MAC0 Rounding Registers after a second SYSCLK cycle, and MAC0SC is cleared to ‘0’). The direction of the arithmetic shift is
controlled by the MAC0SD bit (MAC0CF.4). When this bit is cleared to ‘0’, the MAC0 accumulator will shift
left. When the MAC0SD bit is set to ‘1’, the MAC0 accumulator will shift right. Right-shift operations are
sign-extended with the current value of bit 39. Note that the status flags in the MAC0STA register are not
affected by shift operations.
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11.6. Rounding and Saturation
A Rounding Engine is included, which can be used to provide a rounded result when operating on fractional numbers. MAC0 uses an unbiased rounding algorithm to round the data stored in bits 31–16 of the
accumulator, as shown in Table 11.1. Rounding occurs during the third stage of the MAC0 pipeline, after
any shift operation, or on a write to the LSB of the accumulator. The rounded results are stored in the
rounding registers: MAC0RNDH (SFR Definition 11.12) and MAC0RNDL (SFR Definition 11.13). The accumulator registers are not affected by the rounding engine. Although rounding is primarily used for fractional
data, the data in the rounding registers is updated in the same way when operating in integer mode.
Table 11.1. MAC0 Rounding (MAC0SAT = 0)
Accumulator Bits 15–0
(MAC0ACC1:MAC0ACC0)
Accumulator Bits 31–16
(MAC0ACC3:MAC0ACC2)
Rounding
Direction
Rounded Results
(MAC0RNDH:MAC0RNDL)
Greater Than 0x8000
Anything
Up
(MAC0ACC3:MAC0ACC2) + 1
Less Than 0x8000
Anything
Down
(MAC0ACC3:MAC0ACC2)
Equal To 0x8000
Odd (LSB = 1)
Up
(MAC0ACC3:MAC0ACC2) + 1
Equal To 0x8000
Even (LSB = 0)
Down
(MAC0ACC3:MAC0ACC2)
The rounding engine can also be used to saturate the results stored in the rounding registers. If the MAC0SAT bit is set to ‘1’ and the rounding register overflows, the rounding registers will saturate. When a positive overflow occurs, the rounding registers will show a value of 0x7FFF when saturated. For a negative
overflow, the rounding registers will show a value of 0x8000 when saturated. If the MAC0SAT bit is cleared
to ‘0’, the rounding registers will not saturate.
11.7. Usage Examples
This section details some software examples for using MAC0. Section 11.7.1 shows a series of two MAC
operations using fractional numbers. Section 11.7.2 shows a single operation in Multiply Only mode with
integer numbers. The last example, shown in Section 11.7.3, demonstrates how the left-shift and right-shift
operations can be used to modify the accumulator. All of the examples assume that all of the flags in the
MAC0STA register are initially set to ‘0’.
11.7.1. Multiply and Accumulate Example
The example below implements the equation:
0.5 0.25 + 0.5 – 0.25 = 0.125 – 0.125 = 0.0
MOV
MOV
MOV
MOV
MOV
MOV
MOV
NOP
NOP
NOP
MAC0CF,
MAC0AH,
MAC0AL,
MAC0BH,
MAC0BL,
MAC0BH,
MAC0BL,
#0Ah
#40h
#00h
#20h
#00h
#E0h
#00h
; Set to Clear Accumulator, Use fractional numbers
; Load MAC0A register with 4000 hex = 0.5 decimal
;
;
;
;
Load
This
Load
This
MAC0B register
line initiates
MAC0B register
line initiates
with 2000 hex = 0.25 decimal
the first MAC operation
with E000 hex = -0.25 decimal
the second MAC operation
; After this instruction, the Accumulator should be equal to 0,
; and the MAC0STA register should be 0x04, indicating a zero
; After this instruction, the Rounding register is updated
Rev. 1.2
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11.7.2. Multiply Only Example
The example below implements the equation:
4660 – 292 = – 1360720
MOV
MOV
MOV
MOV
MOV
NOP
NOP
MAC0CF,
MAC0AH,
MAC0AL,
MAC0BH,
MAC0BL,
#01h
#12h
#34h
#FEh
#DCh
; Use integer numbers, and multiply only mode (add to zero)
; Load MAC0A register with 1234 hex = 4660 decimal
; Load MAC0B register with FEDC hex = -292 decimal
; This line initiates the Multiply operation
;
;
;
;
NOP
After this instruction, the Accumulator should be equal to
FFFFEB3CB0 hex = -1360720 decimal. The MAC0STA register should
be 0x01, indicating a negative result.
After this instruction, the Rounding register is updated
11.7.3. MAC0 Accumulator Shift Example
The example below shifts the MAC0 accumulator left one bit, and then right two bits:
MOV
MOV
MOV
MOV
MOV
MOV
NOP
NOP
MOV
MOV
NOP
NOP
122
MAC0OVR, #40h
MAC0ACC3, #88h
MAC0ACC2, #44h
MAC0ACC1, #22h
MAC0ACC0, #11h
MAC0CF, #20h
MAC0CF, #30h
MAC0CF, #30h
; The next few instructions load the accumulator with the value
; 4088442211 Hex.
;
;
;
;
;
;
;
Initiate a Left-shift
After this instruction, the accumulator should be 0x8110884422
The rounding register is updated after this instruction
Initiate a Right-shift
Initiate a second Right-shift
After this instruction, the accumulator should be 0xE044221108
The rounding register is updated after this instruction
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 11.1. MAC0CF: MAC0 Configuration
SFR Page:
0
SFR Address: 0xD7
R
R
–
–
Bit7
Bit6
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
MAC0SC MAC0SD MAC0CA MAC0SAT MAC0FM MAC0MS 00000000
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–6: UNUSED: Read = 00b, Write = don’t care.
Bit 5:
MAC0SC: Accumulator Shift Control.
When set to 1, the 40-bit MAC0 Accumulator register will be shifted during the next SYSCLK
cycle. The direction of the shift (left or right) is controlled by the MAC0SD bit.
This bit is cleared to ‘0’ by hardware when the shift is complete.
Bit 4:
MAC0SD: Accumulator Shift Direction.
This bit controls the direction of the accumulator shift activated by the MAC0SC bit.
0: MAC0 Accumulator will be shifted left.
1: MAC0 Accumulator will be shifted right.
Bit 3:
MAC0CA: Clear Accumulator.
This bit is used to reset MAC0 before the next operation.
When set to ‘1’, the MAC0 Accumulator will be cleared to zero and the MAC0 Status register
will be reset during the next SYSCLK cycle.
This bit will be cleared to ‘0’ by hardware when the reset is complete.
Bit 2:
MAC0SAT: Saturate Rounding Register.
This bit controls whether the Rounding Register will saturate. If this bit is set and a Soft
Overflow occurs, the Rounding Register will saturate. This bit does not affect the operation
of the MAC0 Accumulator. See Section 11.6 for more details about rounding and saturation.
0: Rounding Register will not saturate.
1: Rounding Register will saturate.
Bit 1:
MAC0FM: Fractional Mode.
This bit selects between Integer Mode and Fractional Mode for MAC0 operations.
0: MAC0 operates in Integer Mode.
1: MAC0 operates in Fractional Mode.
Bit 0:
MAC0MS: Mode Select
This bit selects between MAC Mode and Multiply Only Mode.
0: MAC (Multiply and Accumulate) Mode.
1: Multiply Only Mode.
Note:The contents of this register should not be changed by software during the first two MAC0 pipeline stages.
Rev. 1.2
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SFR Definition 11.2. MAC0STA: MAC0 Status
SFR Page:
0
SFR Address: 0xCF
R
R
R
R
R/W
R/W
R/W
R/W
Reset Value
–
–
–
–
MAC0HO
MAC0Z
MAC0SO
MAC0N
00000100
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
Bits 7–4: UNUSED: Read = 0000b, Write = don’t care.
Bit 3:
MAC0HO: Hard Overflow Flag.
This bit is set to ‘1’ whenever an overflow out of the MAC0OVR register occurs during a
MAC operation (i.e. when MAC0OVR changes from 0x7F to 0x80 or from 0x80 to 0x7F).
The hard overflow flag must be cleared in software by directly writing it to ‘0’, or by resetting
the MAC logic using the MAC0CA bit in register MAC0CF.
Bit 2:
MAC0Z: Zero Flag.
This bit is set to ‘1’ if a MAC0 operation results in an Accumulator value of zero. If the result
is non-zero, this bit will be cleared to ‘0’.
Bit 1:
MAC0SO: Soft Overflow Flag.
This bit is set to ‘1’ when a MAC operation causes an overflow into the sign bit (bit 31) of the
MAC0 Accumulator. If the overflow condition is corrected after a subsequent MAC operation,
this bit is cleared to ‘0’.
Bit 0:
MAC0N: Negative Flag.
If the MAC Accumulator result is negative, this bit will be set to ‘1’. If the result is positive or
zero, this flag will be cleared to ‘0’.
Note:
The contents of this register should not be changed by software during the first two MAC0 pipeline
stages.
SFR Definition 11.3. MAC0AH: MAC0 A High Byte
SFR Page:
0
SFR Address: 0xA5
R
R
R
R
R
R
R
R
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: High Byte (bits 15–8) of MAC0 A Register.
124
Rev. 1.2
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SFR Definition 11.4. MAC0AL: MAC0 A Low Byte
SFR Page:
0
SFR Address: 0xA4
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Low Byte (bits 7–0) of MAC0 A Register.
SFR Definition 11.5. MAC0BH: MAC0 B High Byte
SFR Page:
0
SFR Address: 0xF2
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: High Byte (bits 15–8) of MAC0 B Register.
SFR Definition 11.6. MAC0BL: MAC0 B Low Byte
SFR Page:
0
SFR Address: 0xF1
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Low Byte (bits 7–0) of MAC0 B Register.
A write to this register initiates a Multiply or Multiply and Accumulate operation.
Note:The contents of this register should not be changed by software during the first MAC0 pipeline stage.
Rev. 1.2
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SFR Definition 11.7. MAC0ACC3: MAC0 Accumulator Byte 3
SFR Page:
0
SFR Address: 0xD5
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Byte 3 (bits 31–24) of MAC0 Accumulator.
Note:The contents of this register should not be changed by software during the first two MAC0 pipeline stages.
SFR Definition 11.8. MAC0ACC2: MAC0 Accumulator Byte 2
SFR Page:
0
SFR Address: 0xD4
R
R
R
R
R
R
R
R
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: Byte 2 (bits 23–16) of MAC0 Accumulator.
Note:The contents of this register should not be changed by software during the first two MAC0 pipeline stages.
SFR Definition 11.9. MAC0ACC1: MAC0 Accumulator Byte 1
SFR Page:
0
SFR Address: 0xD3
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Byte 1 (bits 15–8) of MAC0 Accumulator.
Note:The contents of this register should not be changed by software during the first two MAC0 pipeline stages.
126
Rev. 1.2
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SFR Definition 11.10. MAC0ACC0: MAC0 Accumulator Byte 0
SFR Page:
0
SFR Address: 0xD2
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Byte 0 (bits 7–0) of MAC0 Accumulator.
Note:The contents of this register should not be changed by software during the first two MAC0 pipeline stages.
SFR Definition 11.11. MAC0OVR: MAC0 Accumulator Overflow
SFR Page:
0
SFR Address: 0xD6
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: MAC0 Accumulator Overflow Bits (bits 39–32).
Note:The contents of this register should not be changed by software during the first two MAC0 pipeline stages.
SFR Definition 11.12. MAC0RNDH: MAC0 Rounding Register High Byte
SFR Page:
0
SFR Address: 0xAF
R
R
R
R
R
R
R
R
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: High Byte (bits 15–8) of MAC0 Rounding Register.
Rev. 1.2
127
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 11.13. MAC0RNDL: MAC0 Rounding Register Low Byte
SFR Page:
0
SFR Address: 0xAE
R
R
R
R
R
R
R
R
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bits 7–0: Low Byte (bits 7–0) of MAC0 Rounding Register.
128
Rev. 1.2
Bit2
Bit1
Bit0
C8051F360/1/2/3/4/5/6/7/8/9
12. Reset Sources
Reset circuitry allows the controller to be easily placed in a predefined default condition. On entry to this
reset state, the following occur:
•
•
•
•
CIP-51 halts program execution
Special Function Registers (SFRs) are initialized to their defined reset values
External Port pins are forced to a known state
Interrupts and timers are disabled.
All SFRs are reset to the predefined values noted in the SFR detailed descriptions. The contents of internal
data memory are unaffected during a reset; any previously stored data is preserved. However, since the
stack pointer SFR is reset, the stack is effectively lost, even though the data on the stack is not altered.
The Port I/O latches are reset to 0xFF (all logic ones) in open-drain mode. Weak pullups are enabled
during and after the reset. For VDD Monitor and power-on resets, the RST pin is driven low until the device
exits the reset state.
On exit from the reset state, the program counter (PC) is reset, and the system clock defaults to the internal oscillator. Refer to Section “16. Oscillators” on page 170 for information on selecting and configuring
the system clock source. The Watchdog Timer is enabled with the system clock divided by 12 as its clock
source (Section “22.3. Watchdog Timer Mode” on page 273 details the use of the Watchdog Timer). Program execution begins at location 0x0000.
VDD
Power On
Reset
Supply
Monitor
+
-
'0'
Enable
(wired-OR)
/RST
C0RSEF
Missing
Clock
Detector
(oneshot)
EN
Reset
Funnel
PCA
WDT
(Software Reset)
SWRSF
Errant
FLASH
Operation
EN
System
Clock
WDT
Enable
Px.x
+
-
Comparator 0
MCD
Enable
Px.x
CIP-51
Microcontroller
Core
System Reset
Extended Interrupt
Handler
Figure 12.1. Reset Sources
Rev. 1.2
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12.1. Power-On Reset
During power-up, the device is held in a reset state and the RST pin is driven low until VDD settles above
VRST. A delay occurs before the device is released from reset; the delay decreases as the VDD ramp time
increases (VDD ramp time is defined as how fast VDD ramps from 0 V to VRST). Figure 12.2. plots the
power-on and VDD Monitor reset timing. For ramp times less than 1 ms, the power-on reset delay (TPORDelay) is typically less than 0.3 ms.
Note: The maximum VDD ramp time is 1 ms; slower ramp times may cause the device to be released from
reset before VDD reaches the VRST level.
volts
On exit from a power-on reset, the PORSF flag (RSTSRC.1) is set by hardware to logic ‘1’. When PORSF
is set, all of the other reset flags in the RSTSRC Register are indeterminate (PORSF is cleared by all other
resets). Since all resets cause program execution to begin at the same location (0x0000) software can
read the PORSF flag to determine if a power-up was the cause of reset. The content of internal data memory should be assumed to be undefined after a power-on reset. The VDD Monitor is enabled following a
power-on reset.
VDD
2.70
2.55
VRST
VD
D
2.0
1.0
t
Logic HIGH
Logic LOW
/RST
TPORDelay
VDD
Monitor
Reset
Power-On
Reset
Figure 12.2. Power-On and VDD Monitor Reset Timing
130
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12.2. Power-Fail Reset/VDD Monitor
When a power-down transition or power irregularity causes VDD to drop below VRST, the power supply
monitor will drive the RST pin low and hold the CIP-51 in a reset state (see Figure 12.2). When VDD returns
to a level above VRST, the CIP-51 will be released from the reset state. Note that even though internal data
memory contents are not altered by the power-fail reset, it is impossible to determine if VDD dropped below
the level required for data retention. If the PORSF flag reads ‘1’, the data may no longer be valid. The VDD
Monitor is enabled after power-on resets; however its defined state (enabled/disabled) is not altered by any
other reset source. For example, if the VDD Monitor is disabled and a software reset is performed, the VDD
Monitor will still be disabled after the reset. To protect the integrity of Flash contents, the VDD Monitor
must be enabled and selected as a reset source if software contains routines which erase or write
Flash memory. If the VDD Monitor is not enabled, any erase or write performed on Flash memory
will cause a Flash Error device reset.
The VDD Monitor must be enabled before it is selected as a reset source. Selecting the VDD Monitor
as a reset source before it is enabled and stabilized may cause a system reset. The procedure for configuring the VDD Monitor as a reset source is shown below:
Step 1. Enable the VDD Monitor (VDMEN bit in VDM0CN = ‘1’).
Step 2. Wait for the VDD Monitor to stabilize (approximately 5 µs).
Note: This delay should be omitted if software contains routines which erase or
write Flash memory.
Step 3. Select the VDD Monitor as a reset source (PORSF bit in RSTSRC = ‘1’).
See Table 12.1 for complete electrical characteristics of the VDD Monitor.
Note: Software should take care not to inadvertently disable the VDD Monitor as a reset source
when writing to RSTSRC to enable other reset sources or to trigger a software reset. All writes to
RSTSRC should explicitly set PORSF to '1' to keep the VDD Monitor enabled as a reset source.
Rev. 1.2
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SFR Definition 12.1. VDM0CN: VDD Monitor Control
SFR Page:
all pages
SFR Address: 0xFF
R/W
VDMEN
Bit7
R
R
R
R
R
R
R
VDDSTAT Reserved Reserved Reserved Reserved Reserved Reserved
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Reset Value
Variable
Bit0
Bit 7:
VDMEN: VDD Monitor Enable.
This bit turns the VDD Monitor circuit on/off. The VDD Monitor cannot generate system resets
until it is also selected as a reset source in register RSTSRC (SFR Definition 12.2). The VDD
Monitor must be allowed to stabilize before it is selected as a reset source. Selecting the
VDD Monitor as a reset source before it has stabilized may generate a system reset.
0: VDD Monitor Disabled.
1: VDD Monitor Enabled.
Bit 6:
VDD STAT: VDD Status.
This bit indicates the current power supply status (VDD Monitor output).
0: VDD is at or below the VDD Monitor threshold.
1: VDD is above the VDD Monitor threshold.
Bits 5–0: RESERVED. Read = Variable. Write = don’t care.
12.3. External Reset
The external RST pin provides a means for external circuitry to force the device into a reset state. Asserting an active-low signal on the RST pin generates a reset; an external pullup and/or decoupling of the RST
pin may be necessary to avoid erroneous noise-induced resets. See Table 12.1 for complete RST pin
specifications. The PINRSF flag (RSTSRC.0) is set on exit from an external reset.
12.4. Missing Clock Detector Reset
The Missing Clock Detector (MCD) is a one-shot circuit that is triggered by the system clock. If the system
clock remains high or low for more than 100 µs, the one-shot will time out and generate a reset. After a
MCD reset, the MCDRSF flag (RSTSRC.2) will read ‘1’, signifying the MCD as the reset source; otherwise,
this bit reads ‘0’. Writing a ‘1’ to the MCDRSF bit enables the Missing Clock Detector; writing a ‘0’ disables
it. The state of the RST pin is unaffected by this reset.
12.5. Comparator0 Reset
Comparator0 can be configured as a reset source by writing a ‘1’ to the C0RSEF flag (RSTSRC.5). Comparator0 should be enabled and allowed to settle prior to writing to C0RSEF to prevent any turn-on chatter
on the output from generating an unwanted reset. The Comparator0 reset is active-low: if the non-inverting
input voltage (on CP0+) is less than the inverting input voltage (on CP0-), the device is put into the reset
state. After a Comparator0 reset, the C0RSEF flag (RSTSRC.5) will read ‘1’ signifying Comparator0 as the
reset source; otherwise, this bit reads ‘0’. The state of the RST pin is unaffected by this reset.
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12.6. PCA Watchdog Timer Reset
The programmable Watchdog Timer (WDT) function of the Programmable Counter Array (PCA) can be
used to prevent software from running out of control during a system malfunction. The PCA WDT function
can be enabled or disabled by software as described in Section “22.3. Watchdog Timer Mode” on
page 273; the WDT is enabled and clocked by SYSCLK / 12 following any reset. If a system malfunction
prevents user software from updating the WDT, a reset is generated and the WDTRSF bit (RSTSRC.5) is
set to ‘1’. The state of the RST pin is unaffected by this reset.
12.7. Flash Error Reset
If a Flash read/write/erase or program read targets an illegal address, a system reset is generated. This
may occur due to any of the following:
•
•
•
•
•
A Flash write or erase is attempted above user code space. This occurs when PSWE is set to ‘1’ and a
MOVX write operation targets an address above address 0x7BFF.
A Flash read is attempted above user code space. This occurs when a MOVC operation targets an
address above address 0x7BFF.
A Program read is attempted above user code space. This occurs when user code attempts to branch
to an address above 0x7BFF.
A Flash read, write or erase attempt is restricted due to a Flash security setting (see Section
“13.2. Security Options” on page 139).
A Flash write or erase is attempted while the VDD Monitor is disabled.
The FERROR bit (RSTSRC.6) is set following a Flash error reset. The state of the RST pin is unaffected by
this reset.
12.8. Software Reset
Software may force a reset by writing a ‘1’ to the SWRSF bit (RSTSRC.4). The SWRSF bit will read ‘1’ following a software forced reset. The state of the RST pin is unaffected by this reset.
Rev. 1.2
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SFR Definition 12.2. RSTSRC: Reset Source
SFR Page:
all pages
SFR Address: 0xEF
R
–
Bit7
R
R/W
FERROR C0RSEF
Bit6
Bit5
R/W
SWRSF
Bit4
R
R/W
WDTRSF MCDRSF
Bit3
Bit2
R/W
R
Reset Value
PORSF
PINRSF
Variable
Bit1
Bit0
Note:For bits that act as both reset source enables (on a write) and reset indicator flags (on a read),
read-modify-write instructions read and modify the source enable only. [This applies to bits:
C0RSEF, SWRSF, MCDRSF, PORSF].
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
134
UNUSED. Read = 0b. Write = don’t care.
FERROR: Flash Error Indicator.
0: Source of last reset was not a Flash read/write/erase error.
1: Source of last reset was a Flash read/write/erase error.
C0RSEF: Comparator0 Reset Enable and Flag.
0: Read: Source of last reset was not Comparator0. Write: Comparator0 is not a reset
source.
1: Read: Source of last reset was Comparator0. Write: Comparator0 is a reset source
(active-low).
SWRSF: Software Reset Force and Flag.
0: Read: Source of last reset was not a write to the SWRSF bit. Write: No Effect.
1: Read: Source of last reset was a write to the SWRSF bit. Write: Forces a system reset.
WDTRSF: Watchdog Timer Reset Flag.
0: Source of last reset was not a WDT timeout.
1: Source of last reset was a WDT timeout.
MCDRSF: Missing Clock Detector Flag.
0: Read: Source of last reset was not a Missing Clock Detector timeout. Write: Missing
Clock Detector disabled.
1: Read: Source of last reset was a Missing Clock Detector timeout. Write: Missing Clock
Detector enabled; triggers a reset if a missing clock condition is detected.
PORSF: Power-On Reset Force and Flag.
This bit is set anytime a power-on reset occurs. Writing this bit enables/disables the VDD
Monitor as a reset source. Note: writing ‘1’ to this bit before the VDD Monitor is enabled
and stabilized may cause a system reset. See register VDM0CN (SFR Definition 12.1)
0: Read: Last reset was not a power-on or VDD Monitor reset. Write: VDD Monitor is not a
reset source.
1: Read: Last reset was a power-on or VDD Monitor reset; all other reset flags
indeterminate. Write: VDD Monitor is a reset source.
PINRSF: HW Pin Reset Flag.
0: Source of last reset was not RST pin.
1: Source of last reset was RST pin.
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Table 12.1. Reset Electrical Characteristics
–40 to +85 °C unless otherwise specified.
Parameter
Min
Typ
Max
Units
—
—
0.6
V
RST Input High Voltage
0.7 x VDD
—
—
V
RST Input Low Voltage
—
—
0.7
V
RST Input Pullup Impedance
—
100
—
k
VDD POR Threshold (VRST)
2.40
2.55
2.70
V
RST Output Low Voltage
Conditions
IOL = 8.5 mA,
VDD = 2.7 V to 3.6 V
Missing Clock Detector Timeout
Time from last system clock
rising edge to reset initiation
100
400
600
µs
Reset Time Delay
Delay between release of any
reset source and code
execution at location 0x0000
40
—
—
µs
Minimum RST Low Time to
Generate a System Reset
15
—
—
µs
VDD Monitor Supply Current
—
19
40
µA
Rev. 1.2
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13. Flash Memory
All devices include either 32 kB (C8051F360/1/2/3/4/5/6/7) or 16 kB (C8051F368/9) of on-chip, reprogrammable Flash memory for program code or non-volatile data storage. The Flash memory can be programmed in-system through the C2 interface, or by software using the MOVX write instructions. Once
cleared to logic ‘0’, a Flash bit must be erased to set it back to logic ‘1’. Bytes should be erased (set to
0xFF) before being reprogrammed. Flash write and erase operations are automatically timed by hardware
for proper execution. During a Flash erase or write, the FLBUSY bit in the FLSTAT register is set to ‘1’
(see SFR Definition 14.5). During this time, instructions that are located in the prefetch buffer or the branch
target cache can be executed, but the processor will stall until the erase or write is completed if instruction
data must be fetched from Flash memory. Interrupts that have been pre-loaded into the branch target
cache can also be serviced at this time, if the current code is also executing from the prefetch engine or
cache memory. Any interrupts that are not pre-loaded into cache, or that occur while the core is halted, will
be held in a pending state during the Flash write/erase operation, and serviced in priority order once the
Flash operation has completed. Refer to Table 13.2 for the electrical characteristics of the Flash memory.
13.1. Programming the Flash Memory
The simplest means of programming the Flash memory is through the C2 interface using programming
tools provided by Silicon Labs or a third party vendor. This is the only means for programming a non-initialized device. For details on the C2 commands to program Flash memory, see Section “24. C2 Interface” on
page 286. For detailed guidelines on writing or erasing Flash from firmware, please see Section
“13.3. Flash Write and Erase Guidelines” on page 141.
The Flash memory can be programmed from software using the MOVX write instruction with the address
and data byte to be programmed provided as normal operands. Before writing to Flash memory using
MOVX, Flash write operations must be enabled by setting the PSWE Program Store Write Enable bit
(PSCTL.0) to logic ‘1’. This directs the MOVX writes to Flash memory instead of to XRAM, which is the
default target. The PSWE bit remains set until cleared by software. To avoid errant Flash writes, it is recommended that interrupts be disabled while the PSWE bit is logic ‘1’.
Flash memory is read using the MOVC instruction. MOVX reads are always directed to XRAM, regardless
of the state of PSWE.
Note: To ensure the integrity of the Flash contents, the on-chip VDD Monitor must be enabled in any
system that includes code that writes and/or erases Flash memory from software. Furthermore,
there should be no delay between enabling the VDD Monitor and enabling the VDD Monitor as a
reset source. Any attempt to write or erase Flash memory while the VDD Monitor disabled will
cause a Flash Error device reset.
A write to Flash memory can clear bits but cannot set them; only an erase operation can set bits in Flash.
A byte location to be programmed must be erased before a new value can be written.
Write/Erase timing is automatically controlled by hardware. Note that on the 32 k Flash devices, 1024
bytes beginning at location 0x7C00 are reserved. Flash writes and erases targeting the reserved area
should be avoided.
13.1.1. Flash Lock and Key Functions
Flash writes and erases by user software are protected with a lock and key function. The Flash Lock and
Key Register (FLKEY) must be written with the correct key codes, in sequence, before Flash operations
may be performed. The key codes are: 0xA5, 0xF1. The timing does not matter, but the codes must be
written in order. If the key codes are written out of order, or the wrong codes are written, Flash writes and
136
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erases will be disabled until the next system reset. Flash writes and erases will also be disabled if a Flash
write or erase is attempted before the key codes have been written properly. The Flash lock resets after
each write or erase; the key codes must be written again before a following Flash operation can be performed. The FLKEY register is detailed in SFR Definition 13.2.
13.1.2. Erasing Flash Pages From Software
The Flash memory can be programmed by software using the MOVX write instruction with the address and
data byte to be programmed provided as normal operands. Before writing to Flash memory using MOVX,
Flash write operations must be enabled by: (1) the PSWE and PSEE bits must be set to ‘1’ (this directs the
MOVX writes to target Flash memory); and (2) Writing the Flash key codes in sequence to the Flash Lock
register (FLKEY). The PSWE bit remains set until cleared by software.
A write to Flash memory can clear bits to logic ‘0’ but cannot set them; only an erase operation can set bits
to logic ‘1’ in Flash. A byte location to be programmed should be erased before a new value is written. The Flash memory is organized in 1024-byte pages. The erase operation applies to an entire page
(setting all bytes in the page to 0xFF). To erase an entire 1024-byte page, perform the following steps:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Disable interrupts (recommended).
Write the first key code to FLKEY: 0xA5.
Write the second key code to FLKEY: 0xF1.
Set PSEE (PSCTL.1) to enable Flash erases.
Set PSWE (PSCTL.0) to redirect MOVX commands to write to Flash.
Use the MOVX instruction to write a data byte to any location within the page to be
erased.
Step 7. Clear PSEE to disable Flash erases.
Step 8. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 9. Re-enable interrupts.
13.1.3. Writing Flash Memory From Software
Bytes in Flash memory can be written one byte at a time, or in small blocks. The CHBLKW bit in register
CCH0CN (SFR Definition 14.1) controls whether a single byte or a block of bytes is written to Flash during
a write operation. When CHBLKW is cleared to ‘0’, the Flash will be written one byte at a time. When
CHBLKW is set to ‘1’, the Flash will be written in blocks of four bytes for addresses in code space. Block
writes are performed in the same amount of time as single byte writes, which can save time when storing
large amounts of data to Flash memory.
For single-byte writes to Flash, bytes are written individually, and the Flash write is performed after each
MOVX write instruction. The recommended procedure for writing Flash in single bytes is as follows:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Disable interrupts.
Clear CHBLKW (register CCH0CN) to select single-byte write mode.
Write the first key code to FLKEY: 0xA5.
Write the second key code to FLKEY: 0xF1.
Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Clear the PSEE bit (register PSCTL).
Use the MOVX instruction to write a data byte to the desired location (repeat as
necessary).
Step 8. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 9. Re-enable interrupts.
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Steps 3–8 must be repeated for each byte to be written
For block Flash writes, the Flash write procedure is only performed after the last byte of each block is written with the MOVX write instruction. When writing to addresses located in any of the four code banks, a
Flash write block is four bytes long, from addresses ending in 00b to addresses ending in 11b. Writes must
be performed sequentially (i.e. addresses ending in 00b, 01b, 10b, and 11b must be written in order). The
Flash write will be performed following the MOVX write that targets the address ending in 11b. The Flash
write will be performed following the MOVX write that targets the address ending in 1b. If any bytes in the
block do not need to be updated in Flash, they should be written to 0xFF. The recommended procedure for
writing Flash in blocks is as follows:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Disable interrupts.
Set CHBLKW (register CCH0CN) to select block write mode.
Write the first key code to FLKEY: 0xA5.
Write the second key code to FLKEY: 0xF1.
Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Clear the PSEE bit (register PSCTL).
Using the MOVX instruction, write the first data byte to the first block location (ending in
00b).
Step 8. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 9. Write the first key code to FLKEY: 0xA5.
Step 10. Write the second key code to FLKEY: 0xF1.
Step 11. Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Step 12. Clear the PSEE bit (register PSCTL).
Step 13. Using the MOVX instruction, write the second data byte to the second block location
(ending in 01b).
Step 14. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 15. Write the first key code to FLKEY: 0xA5.
Step 16. Write the second key code to FLKEY: 0xF1.
Step 17. Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Step 18. Clear the PSEE bit (register PSCTL).
Step 19. Using the MOVX instruction, write the third data byte to the third block location (ending in
10b).
Step 20. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 21. Write the first key code to FLKEY: 0xA5.
Step 22. Write the second key code to FLKEY: 0xF1.
Step 23. Set PSWE (register PSCTL) to redirect MOVX commands to write to Flash.
Step 24. Clear the PSEE bit (register PSCTL).
Step 25. Using the MOVX instruction, write the fourth data byte to the last block location (ending
in 11b).
Step 26. Clear the PSWE bit to redirect MOVX commands to the XRAM data space.
Step 27. Re-enable interrupts.
Steps 3-26 must be repeated for each block to be written.
13.1.4. Non-volatile Data Storage
The Flash memory can be used for non-volatile data storage as well as program code. This allows data
such as calibration coefficients to be calculated and stored at run time. Data is written and erased using the
MOVX write instruction (as described in Section 13.1.2 and Section 13.1.3) and read using the MOVC
instruction. Note: MOVX read instructions always target XRAM.
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13.2. Security Options
The CIP-51 provides security options to protect the Flash memory from inadvertent modification by software as well as to prevent the viewing of proprietary program code and constants. The Program Store
Write Enable (bit PSWE in register PSCTL) and the Program Store Erase Enable (bit PSEE in register
PSCTL) bits protect the Flash memory from accidental modification by software. PSWE must be explicitly
set to ‘1’ before software can modify the Flash memory; both PSWE and PSEE must be set to ‘1’ before
software can erase Flash memory. Additional security features prevent proprietary program code and data
constants from being read or altered across the C2 interface.
A Security Lock Byte located at the last byte of Flash user space offers protection of the Flash program
memory from access (reads, writes, or erases) by unprotected code or the C2 interface. The Flash security
mechanism allows the user to lock n 1024-byte Flash pages, starting at page 0 (addresses 0x0000 to
0x03FF), where n is the 1’s complement number represented by the Security Lock Byte. Note that the
page containing the Flash Security Lock Byte is unlocked when no other Flash pages are locked
(all bits of the Lock Byte are ‘1’) and locked when any other Flash pages are locked (any bit of the
Lock Byte is ‘0’). See the example below for an C8051F360.
Security Lock Byte:
1’s Complement:
Flash pages locked:
11111101b
00000010b
3 (First two Flash pages + Lock Byte Page)
0x0000 to 0x07FF (first two Flash pages) and
Addresses locked:
0x7800 to 0x7BFF (Lock Byte Page)
‘F360/1/2/3/4/5/6/7
'F368/9
Reserved
Reserved
0x4000
0x7C00
0x7BFF
Lock Byte
Lock Byte
Locked when any
other Flash pages are
locked
0x7BFE
0x7800
0x3FFF
0x3FFE
0x3C00
Flash memory organized
in 1024-byte pages
Unlocked Flash Pages
Unlocked Flash Pages
Access limit set
according to the Flash
security lock byte
0x0000
0x0000
Figure 13.1. Flash Program Memory Map
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13.2.1. Summary of Flash Security Options
The level of Flash security depends on the Flash access method. The three Flash access methods that
can be restricted are reads, writes, and erases from the C2 debug interface, user firmware executing on
unlocked pages, and user firmware executing on locked pages. Table 13.1 summarizes the Flash security
features of the C8051F36x devices.
Table 13.1. Flash Security Summary
Action
C2 Debug
Interface
User Firmware executing from:
an unlocked page
a locked page
Permitted
Permitted
Permitted
Not Permitted
FEDR
Permitted
Read or Write page containing Lock Byte
(if no pages are locked)
Permitted
Permitted
Permitted
Read or Write page containing Lock Byte
(if any page is locked)
Not Permitted
FEDR
Permitted
Read contents of Lock Byte
(if no pages are locked)
Permitted
Permitted
Permitted
Read contents of Lock Byte
(if any page is locked)
Not Permitted
FEDR
Permitted
Permitted
FEDR
FEDR
Only C2DE
FEDR
FEDR
Lock additional pages
(change '1's to '0's in the Lock Byte)
Not Permitted
FEDR
FEDR
Unlock individual pages
(change '0's to '1's in the Lock Byte)
Not Permitted
FEDR
FEDR
Read, Write or Erase Reserved Area
Not Permitted
FEDR
FEDR
Read, Write or Erase unlocked pages
(except page with Lock Byte)
Read, Write or Erase locked pages
(except page with Lock Byte)
Erase page containing Lock Byte
(if no pages are locked)
Erase page containing Lock Byte - Unlock all pages
(if any page is locked)
C2DE - C2 Device Erase (Erases all Flash pages including the page containing the Lock Byte)
FEDR - Not permitted; Causes Flash Error Device Reset (FERROR bit in RSTSRC is '1' after reset)
- All prohibited operations that are performed via the C2 interface are ignored (do not cause device reset).
- Locking any Flash page also locks the page containing the Lock Byte.
- Once written to, the Lock Byte cannot be modified except by performing a C2 Device Erase.
- If user code writes to the Lock Byte, the Lock does not take effect until the next device reset.
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13.3. Flash Write and Erase Guidelines
Any system which contains routines which write or erase Flash memory from software involves some risk
that the write or erase routines will execute unintentionally if the CPU is operating outside its specified
operating range of VDD, system clock frequency, or temperature. This accidental execution of Flash modifying code can result in alteration of Flash memory contents causing a system failure that is only recoverable by re-Flashing the code in the device.
To help prevent the accidental modification of Flash by firmware, the VDD Monitor must be enabled and
enabled as a reset source on C8051F36x devices for the Flash to be successfully modified. If either the
VDD Monitor or the VDD Monitor reset source is not enabled, a Flash Error Device Reset will be generated when the firmware attempts to modify the Flash.
The following guidelines are recommended for any system that contains routines which write or erase
Flash from code.
13.3.1. VDD Maintenance and the VDD Monitor
1. If the system power supply is subject to voltage or current "spikes," add sufficient transient
protection devices to the power supply to ensure that the supply voltages listed in the Absolute
Maximum Ratings table are not exceeded.
2. Make certain that the minimum VDD rise time specification of 1 ms is met. If the system cannot
meet this rise time specification, then add an external VDD brownout circuit to the /RST pin of
the device that holds the device in reset until VDD reaches VRST and re-asserts /RST if VDD
drops below VRST. Please see Table 12.1, “Reset Electrical Characteristics,” on page 135 for
more information on the VDD Monitor Threshold voltage (VRST).
3. Keep the on-chip VDD Monitor enabled and enable the VDD Monitor as a reset source as early
in code as possible. This should be the first set of instructions executed after the Reset Vector.
For 'C'-based systems, this will involve modifying the startup code added by the 'C' compiler.
See your compiler documentation for more details. Make certain that there are no delays in
software between enabling the VDD Monitor and enabling the VDD Monitor as a reset source.
Code examples showing this can be found in AN201, "Writing to Flash from Firmware", available from the Silicon Laboratories web site.
Note: On C8051F36x devices, both the VDD Monitor and the VDD Monitor reset source must
be enabled to write or erase Flash without generating a Flash Error Device Reset.
4. As an added precaution, explicitly enable the VDD Monitor and enable the VDD Monitor as a
reset source inside the functions that write and erase Flash memory. The VDD Monitor enable
instructions should be placed just after the instruction to set PSWE to a '1', but before the
Flash write or erase operation instruction.
5. Make certain that all writes to the RSTSRC (Reset Sources) register use direct assignment
operators and explicitly DO NOT use the bit-wise operators (such as AND or OR). For example, "RSTSRC = 0x02" is correct, but "RSTSRC |= 0x02" is incorrect.
6. Make certain that all writes to the RSTSRC register explicitly set the PORSF bit to a '1'. Areas
to check are initialization code which enables other reset sources, such as the Missing Clock
Detector or Comparator, for example, and instructions which force a Software Reset. A global
search on "RSTSRC" can quickly verify this.
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13.3.2. 16.4.2 PSWE Maintenance
7. Reduce the number of places in code where the PSWE bit (b0 in PSCTL) is set to a '1'. There
should be exactly one routine in code that sets PSWE to a '1' to write Flash bytes and one routine in code that sets both PSWE and PSEE both to a '1' to erase Flash pages.
8. Minimize the number of variable accesses while PSWE is set to a '1'. Handle pointer address
updates and loop maintenance outside the "PSWE = 1; ... PSWE = 0;" area. Code examples
showing this can be found in AN201, "Writing to Flash from Firmware", available from the Silicon Laboratories web site.
9. Disable interrupts prior to setting PSWE to a '1' and leave them disabled until after PSWE has
been reset to '0'. Any interrupts posted during the Flash write or erase operation will be serviced in priority order after the Flash operation has been completed and interrupts have been
re-enabled by software.
10. Make certain that the Flash write and erase pointer variables are not located in XRAM. See
your compiler documentation for instructions regarding how to explicitly locate variables in different memory areas.
11. Add address bounds checking to the routines that write or erase Flash memory to ensure that
a routine called with an illegal address does not result in modification of the Flash.
13.3.3. System Clock
12. If operating from an external crystal, be advised that crystal performance is susceptible to
electrical interference and is sensitive to layout and to changes in temperature. If the system is
operating in an electrically noisy environment, use the internal oscillator or use an external
CMOS clock.
13. If operating from the external oscillator, switch to the internal oscillator during Flash write or
erase operations. The external oscillator can continue to run, and the CPU can switch back to
the external oscillator after the Flash operation has completed.
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SFR Definition 13.1. PSCTL: Program Store Read/Write Control
SFR Page:
0
SFR Address: 0x8F
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
–
–
–
–
–
–
PSEE
PSWE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–2: UNUSED. Read = 000000b, Write = don't care.
Bit 1:
PSEE: Program Store Erase Enable.
Setting this bit allows an entire page of the Flash program memory to be erased provided
the PSWE bit is also set. After setting this bit, a write to Flash memory using the MOVX
instruction will erase the entire page that contains the location addressed by the MOVX
instruction. The value of the data byte written does not matter. Note: The Flash page containing the Read Lock Byte and Write/Erase Lock Byte cannot be erased by software.
0: Flash program memory erasure disabled.
1: Flash program memory erasure enabled.
Bit 0:
PSWE: Program Store Write Enable.
Setting this bit allows writing a byte of data to the Flash program memory using the MOVX
write instruction. The location must be erased prior to writing data.
0: Write to Flash program memory disabled. MOVX write operations target External RAM.
1: Write to Flash program memory enabled. MOVX write operations target Flash memory.
SFR Definition 13.2. FLKEY: Flash Lock and Key
SFR Page:
0
SFR Address: 0xB7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: FLKEY: Flash Lock and Key Register
Write:
This register provides a lock and key function for Flash erasures and writes. Flash writes
and erases are enabled by writing 0xA5 followed by 0xF1 to the FLKEY register. Flash
writes and erases are automatically disabled after the next write or erase is complete. If any
writes to FLKEY are performed incorrectly, or if a Flash write or erase operation is attempted
while these operations are disabled, the Flash will be permanently locked from writes or erasures until the next device reset. If an application never writes to Flash, it can intentionally
lock the Flash by writing a non-0xA5 value to FLKEY from software.
Read:
When read, bits 1-0 indicate the current Flash lock state.
00: Flash is write/erase locked.
01: The first key code has been written (0xA5).
10: Flash is unlocked (writes/erases allowed).
11: Flash writes/erases disabled until the next reset.
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13.4. Flash Read Timing
On reset, the C8051F36x Flash read timing is configured for operation with system clocks up to 25 MHz. If
the system clock will not be increased above 25 MHz, then the Flash timing registers may be left at their
reset value.
For every Flash read or fetch, the system provides an internal Flash read strobe to the Flash memory. The
Flash read strobe lasts for one or two system clock cycles, based on the FLRT bits (FLSCL.4 and
FLSCL.5). If the system clock is greater than 25 MHz, the FLRT bit must be changed to the appropriate setting. Otherwise, data read or fetched from Flash may not represent the actual contents of Flash.
When the Flash read strobe is asserted, Flash memory is active. When it is de-asserted, Flash memory is
in a low power state.
The recommended procedure for updating FLRT is:
Step 1.
Step 2.
Step 3.
Step 4.
Select SYSCLK to 25 MHz or less.
Disable the prefetch engine (CHPFEN = ‘0’ in CCH0CN register).
Set the FLRT bits to the appropriate setting for the SYSCLK.
Enable the prefetch engine (CHPFEN = ‘1’ in CCH0CN register).
SFR Definition 13.3. FLSCL: Flash Memory Control
SFR Page:
0
SFR Address: 0xB6
R/W
R/W
–
–
Bit7
Bit6
R/W
R/W
FLRT
Bit5
R/W
R/W
R/W
R/W
Reset Value
Reserved Reserved Reserved Reserved 00000000
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–6: UNUSED. Read = 00b. Write = don’t care.
Bits 5–4: FLRT: Flash Read Time.
These bits should be programmed to the smallest allowed value, according to the system
clock speed.
00: SYSCLK < 25 MHz.
01: SYSCLK < 50 MHz.
10: SYSCLK < 75 MHz.
11: SYSCLK < 100 MHz.
Bits 3–0: RESERVED. Read = 0000b. Must Write 0000b.
Important Note: When changing the FLRT bits to a lower setting (e.g. when changing from a
value of 11b to 00b), cache reads, cache writes, and the prefetch engine should be
disabled using the CCH0CN register (see SFR Definition 14.1).
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Table 13.2. Flash Electrical Characteristics
VDD = 2.7 to 3.6 V; –40 to +85 °C.
Parameter
Flash Size
Conditions
C8051F360/1/2/3/4/5/6/7
C8051F368/9
Min
20 k
Endurance
Typ
32768*
16384
250 k
Max
Units
Bytes
Erase/Write
Erase Cycle Time
8
10
12
ms
Write Cycle Time
37
47
57
µs
*Note: 1024 Bytes at location 0x7C00 to 0x7FFF are reserved.
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14. Branch Target Cache
The C8051F36x device families incorporate a 32x4 byte branch target cache with a 4-byte prefetch
engine. Because the access time of the Flash memory is 40 ns, and the minimum instruction time is 10 ns
(C8051F360/1/2/3/4/5/6/7) or 20 ns (C8051F368/9), the branch target cache and prefetch engine are necessary for full-speed code execution. Instructions are read from Flash memory four bytes at a time by the
prefetch engine, and given to the CIP-51 processor core to execute. When running linear code (code without any jumps or branches), the prefetch engine alone allows instructions to be executed at full speed.
When a code branch occurs, a search is performed for the branch target (destination address) in the
cache. If the branch target information is found in the cache (called a “cache hit”), the instruction data is
read from the cache and immediately returned to the CIP-51 with no delay in code execution. If the branch
target is not found in the cache (called a “cache miss”), the processor may be stalled for up to four clock
cycles while the next set of four instructions is retrieved from Flash memory. Each time a cache miss
occurs, the requested instruction data is written to the cache if allowed by the current cache settings. A
data flow diagram of the interaction between the CIP-51 and the Branch Target Cache and Prefetch
Engine is shown in Figure 14.1.
Instruction
Data
CIP-51
Flash
Memory
Prefetch
Engine
Branch Target
Cache
Instruction Address
Figure 14.1. Branch Target Cache Data Flow
14.1. Cache and Prefetch Operation
The branch target cache maintains two sets of memory locations: “slots” and “tags”. A slot is where the
cached instruction data from Flash is stored. Each slot holds four consecutive code bytes. A tag contains
the 13 most significant bits of the corresponding Flash address for each four-byte slot. Thus, instruction
data is always cached along four-byte boundaries in code space. A tag also contains a “valid bit”, which
indicates whether a cache location contains valid instruction data. A special cache location (called the linear tag and slot), is reserved for use by the prefetch engine. The cache organization is shown in
Figure 14.2. Each time a Flash read is requested, the address is compared with all valid cache tag locations (including the linear tag). If any of the tag locations match the requested address, the data from that
slot is immediately provided to the CIP-51. If the requested address matches a location that is currently
being read by the prefetch engine, the CIP-51 will be stalled until the read is complete. If a match is not
found, the current prefetch operation is abandoned, and a new prefetch operation is initiated for the
requested instruction data. When the prefetch operation is finished, the CIP-51 begins executing the
instructions that were retrieved, and the prefetch engine begins reading the next four-byte word from Flash
memory. If the newly-fetched data also meets the criteria necessary to be cached, it will be written to the
cache in the slot indicated by the current replacement algorithm.
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The replacement algorithm is selected with the Cache Algorithm bit, CHALGM (CCH0TN.3). When
CHALGM is cleared to ‘0’, the cache will use the rebound algorithm to replace cache locations. The
rebound algorithm replaces locations in order from the beginning of cache memory to the end, and then
from the end of cache memory to the beginning. When CHALGM is set to ‘1’, the cache will use the
pseudo-random algorithm to replace cache locations. The pseudo-random algorithm uses a pseudo-random number to determine which cache location to replace. The cache can be manually emptied by writing
a ‘1’ to the CHFLUSH bit (CCH0CN.4).
Prefetch Data
Valid
Bit
Address
Data
VL
LINEAR TAG
LINEAR SLOT
V0
V1
TAG 0
TAG 1
SLOT 0
SLOT 1
V2
TAG 2
SLOT 2
V27
TAG 27
SLOT 27
V28
V29
V30
TAG 28
TAG 29
TAG 30
SLOT 28
SLOT 29
SLOT 30
V31
TAG 31
SLOT 31
Cache Data
A14
A2
TAG = 13 MSBs of Absolute FLASH Address
A1 A0
0
0
Byte 0
0
1
1
0
1
1
Byte 1
Byte 2
Byte 3
SLOT = 4 Instruction
Data Bytes
Figure 14.2. Branch Target Cache Organization
14.2. Cache and Prefetch Optimization
By default, the branch target cache is configured to provide code speed improvements for a broad range of
circumstances. In most applications, the cache control registers should be left in their reset states.
Sometimes it is desirable to optimize the execution time of a specific routine or critical timing loop. The
branch target cache includes options to exclude caching of certain types of data, as well as the ability to
pre-load and lock time-critical branch locations to optimize execution speed.
The most basic level of cache control is implemented with the Cache Miss Penalty Threshold bits,
CHMSTH (CCH0TN.1–0). If the processor is stalled during a prefetch operation for more clock cycles than
the number stored in CHMSTH, the requested data will be cached when it becomes available. The
CHMSTH bits are set to zero by default, meaning that any time the processor is stalled, the new data will
be cached. If, for example, CHMSTH is equal to 2, any cache miss causing a delay of 3 or 4 clock cycles
will be cached, while a cache miss causing a delay of 1–2 clock cycles will not be cached.
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Certain types of instruction data or certain blocks of code can also be excluded from caching. The destinations of RETI instructions are, by default, excluded from caching. To enable caching of RETI destinations,
the CHRETI bit (CCH0CN.3) can be set to ‘1’. It is generally not beneficial to cache RETI destinations
unless the same instruction is likely to be interrupted repeatedly (such as a code loop that is waiting for an
interrupt to happen). Instructions that are part of an interrupt service routine (ISR) can also be excluded
from caching. By default, ISR instructions are cached, but this can be disabled by clearing the CHISR bit
(CCH0CN.2) to ‘0’. The other information that can be explicitly excluded from caching are the data
returned by MOVC instructions. Clearing the CHMOV bit (CCH0CN.1) to ‘0’ will disable caching of MOVC
data. If MOVC caching is allowed, it can be restricted to only use slot 0 for the MOVC information (excluding cache push operations). The CHFIXM bit (CCH0TN.2) controls this behavior.
Further cache control can be implemented by disabling all cache writes. Cache writes can be disabled by
clearing the CHWREN bit (CCH0CN.7) to ‘0’. Although normal cache writes (such as those after a cache
miss) are disabled, data can still be written to the cache with a cache push operation. Disabling cache
writes can be used to prevent a non-critical section of code from changing the cache contents. Note that
regardless of the value of CHWREN, a Flash write or erase operation automatically removes the affected
bytes from the cache. Cache reads and the prefetch engine can also be individually disabled. Disabling
cache reads forces all instructions data to execute from Flash memory or from the prefetch engine. To disable cache reads, the CHRDEN bit (CCH0CN.6) can be cleared to ‘0’. Note that when cache reads are disabled, cache writes will still occur (if CHWREN is set to ‘1’). Disabling the prefetch engine is accomplished
using the CHPFEN bit (CCH0CN.5). When this bit is cleared to ‘0’, the prefetch engine will be disabled. If
both CHPFEN and CHRDEN are ‘0’, code will execute at a fixed rate, as instructions become available
from the Flash memory.
Cache locations can also be pre-loaded and locked with time-critical branch destinations. For example, in
a system with an ISR that must respond as fast as possible, the entry point for the ISR can be locked into
a cache location to minimize the response latency of the ISR. Up to 30 locations can be locked into the
cache at one time. Instructions are locked into cache by enabling cache push operations with the CHPUSH
bit (CCH0LC.7). When CHPUSH is set to ‘1’, a MOVC instruction will cause the four-byte segment containing the data byte to be written to the cache slot location indicated by CHSLOT (CCH0LC.4-0). CHSLOT is
them decremented to point to the next lockable cache location. This process is called a cache push operation. Cache locations that are above CHSLOT are “locked”, and cannot be changed by the processor core,
as shown in Figure 14.3. Cache locations can be unlocked by using a cache pop operation. A cache pop is
performed by writing a ‘1’ to the CHPOP bit (CCH0LC.6). When a cache pop is initiated, the value of
CHSLOT is incremented. This unlocks the most recently locked cache location, but does not remove the
information from the cache. Note that a cache pop should not be initiated if CHSLOT is equal to 11110b.
Doing so may have an adverse effect on cache performance. Important: Although locking cache location 1 is not explicitly disabled by hardware, the entire cache will be unlocked when CHSLOT is
equal to 00000b. Therefore, cache locations 1 and 0 must remain unlocked at all times.
148
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Cache Push
Operations
Decrement
CHSLOT
CHSLOT = 27
Cache Pop
Operations
Increment
CHSLOT
Lock Status
UNLOCKED
TAG 0
SLOT 0
TAG 1
SLOT 1
TAG 2
SLOT 2
UNLOCKED
UNLOCKED
UNLOCKED
TAG 26
SLOT 26
UNLOCKED
TAG 27
SLOT 27
UNLOCKED
TAG 28
SLOT 28
TAG 29
SLOT 29
LOCKED
LOCKED
TAG 30
SLOT 30
TAG 31
SLOT 31
LOCKED
LOCKED
Figure 14.3. Cache Lock Operation
Rev. 1.2
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C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 14.1. CCH0CN: Cache Control
SFR Page:
F
SFR Address: 0x84
R/W
R/W
R/W
R/W
CHWREN CHRDEN CHPFEN CHFLSH
Bit7
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
150
Bit6
Bit5
Bit4
R/W
R/W
CHRETI
CHISR
Bit3
Bit2
R/W
R/W
Reset Value
CHMOVC CHBLKW 11100110
Bit1
Bit0
CHWREN: Cache Write Enable.
This bit enables the processor to write to the cache memory.
0: Cache contents are not allowed to change, except during Flash writes/erasures or cache
locks.
1: Writes to cache memory are allowed.
CHRDEN: Cache Read Enable.
This bit enables the processor to read instructions from the cache memory.
0: All instruction data comes from Flash memory or the prefetch engine.
1: Instruction data is obtained from cache (when available).
CHPFEN: Cache Prefetch Enable.
This bit enables the prefetch engine.
0: Prefetch engine is disabled.
1: Prefetch engine is enabled.
CHFLSH: Cache Flush.
When written to a ‘1’, this bit clears the cache contents. This bit always reads ‘0’.
CHRETI: Cache RETI Destination Enable.
This bit enables the destination of a RETI address to be cached.
0: Destinations of RETI instructions will not be cached.
1: RETI destinations will be cached.
CHISR: Cache ISR Enable.
This bit allows instructions which are part of an Interrupt Service Routine (ISR) to be cached.
0: Instructions in ISRs will not be loaded into cache memory.
1: Instructions in ISRs can be cached.
CHMOVC: Cache MOVC Enable.
This bit allows data requested by a MOVC instruction to be loaded into the cache memory.
0: Data requested by MOVC instructions will not be cached.
1: Data requested by MOVC instructions will be loaded into cache memory.
CHBLKW: Block Write Enable.
This bit allows block writes to Flash memory from software.
0: Each byte of a software Flash write is written individually.
1: Flash bytes are written in groups of four (for code space writes).
Rev. 1.2
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SFR Definition 14.2. CCH0TN: Cache Tuning
SFR Page:
F
SFR Address: 0xC9
R/W
R/W
R/W
R/W
CHMSCTL
Bit7
Bit6
Bit5
R/W
R/W
CHALGM CHFIXM
Bit4
Bit3
Bit2
R/W
R/W
CHMSTH
Bit1
Reset Value
00000100
Bit0
Bits 7–4: CHMSCTL: Cache Miss Penalty Accumulator (Bits 4–1).
These are bits 4-1 of the Cache Miss Penalty Accumulator. To read these bits, they must first
be latched by reading the CHMSCTH bits in the CCH0MA Register (See SFR Definition
14.4).
Bit 3:
CHALGM: Cache Algorithm Select.
This bit selects the cache replacement algorithm.
0: Cache uses Rebound algorithm.
1: Cache uses Pseudo-random algorithm.
Bit 2:
CHFIXM: Cache Fix MOVC Enable.
This bit forces MOVC writes to the cache memory to use slot 0.
0: MOVC data is written according to the current algorithm selected by the CHALGM bit.
1: MOVC data is always written to cache slot 0.
Bits 1–0: CHMSTH: Cache Miss Penalty Threshold.
These bits determine when missed instruction data will be cached.
If data takes longer than CHMSTH clocks to obtain, it will be cached.
Rev. 1.2
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SFR Definition 14.3. CCH0LC: Cache Lock Control
SFR Page:
F
SFR Address: 0xD2
R/W
R/W
CHPUSH
Bit7
Bit 7:
R
R
R
CHPOP RESERVED
Bit6
Bit5
R
R
R
Bit1
Bit0
CHSLOT
Bit4
Bit3
Bit2
Reset Value
00011111
CHPUSH: Cache Push Enable.
This bit enables cache push operations, which will lock information in cache slots using
MOVC instructions.
0: Cache push operations are disabled.
1: Cache push operations are enabled. When a MOVC read is executed, the requested 4byte segment containing the data is locked into the cache at the location indicated by
CHSLOT, and CHSLOT is decremented.
Note:No more than 30 cache slots should be locked at one time, since the entire cache will be unlocked
when CHSLOT is equal to 0.
Bit 6:
CHPOP: Cache Pop.
Writing a ‘1’ to this bit will increment CHSLOT and then unlock that location. This bit always
reads ‘0’. Note that Cache Pop operations should not be performed while CHSLOT =
11110b. “Pop”ing more Cache slots than have been “Push”ed will have indeterminate results
on the Cache performance.
Bit 5:
RESERVED. Read = 0b. Must Write 0b.
Bits 4–0: CHSLOT: Cache Slot Pointer.
These read-only bits are the pointer into the cache lock stack. Locations above CHSLOT are
locked, and will not be changed by the processor, except when CHSLOT equals 0.
152
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SFR Definition 14.4. CCH0MA: Cache Miss Accumulator
SFR Page:
F
SFR Address: 0xD3
R
R/W
R/W
R/W
CHMSOV
Bit7
R/W
R/W
R/W
R/W
CHMSCTH
Bit6
Bit5
Bit4
Bit3
Reset Value
00000000
Bit2
Bit1
Bit0
Bit 7:
CHMSOV: Cache Miss Penalty Overflow.
This bit indicates when the Cache Miss Penalty Accumulator has overflowed since it was
last written.
0: The Cache Miss Penalty Accumulator has not overflowed since it was last written.
1: An overflow of the Cache Miss Penalty Accumulator has occurred since it was last written.
Bits 6–0: CHMSCTH: Cache Miss Penalty Accumulator (bits 11–5)
These are bits 11-5 of the Cache Miss Penalty Accumulator. The next four bits (bits 4-1) are
stored in CHMSCTL in the CCH0TN register.
The Cache Miss Penalty Accumulator is incremented every clock cycle that the processor is
delayed due to a cache miss. This is primarily used as a diagnostic feature, when optimizing
code for execution speed.
Writing to CHMSCTH clears the lower 5 bits of the Cache Miss Penalty Accumulator.
Reading from CHMSCTH returns the current value of CHMSTCH, and latches bits 4-1 into
CHMSTCL so that they can be read. Because bit 0 of the Cache Miss Penalty Accumulator
is not available, the Cumulative Miss Penalty is equal to 2 * (CCHMSTCH:CCHMSTCL).
SFR Definition 14.5. FLSTAT: Flash Status
SFR Page:
F
SFR Address: 0xAC
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Reserved Reserved Reserved Reserved Reserved Reserved Reserved FLBUSY 00000000
Bit7
Bit 7–1:
Bit 0:
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
RESERVED. Read = 0000000b. Must Write 0000000b.
FLBUSY: Flash Busy
This bit indicates when a Flash write or erase operation is in progress.
0: Flash is idle or reading.
1: Flash write/erase operation is currently in progress.
Rev. 1.2
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15. External Data Memory Interface and On-Chip XRAM
For C8051F36x devices, 1k Bytes of RAM are included on-chip and mapped into the external data memory
space (XRAM). Additionally, an External Memory Interface (EMIF) is available on the C8051F360/3
devices, which can be used to access off-chip data memories and memory-mapped devices connected to
the GPIO ports. The external memory space may be accessed using the external move instruction
(MOVX) and the data pointer (DPTR), or using the MOVX indirect addressing mode using R0 or R1. If the
MOVX instruction is used with an 8-bit address operand (such as @R1), then the high byte of the 16-bit
address is provided by the External Memory Interface Control Register (EMI0CN, shown in SFR Definition
15.1). Note: the MOVX instruction can also be used for writing to the FLASH memory. See Section
“13. Flash Memory” on page 136 for details. The MOVX instruction accesses XRAM by default.
15.1. Accessing XRAM
The XRAM memory space is accessed using the MOVX instruction. The MOVX instruction has two forms,
both of which use an indirect addressing method. The first method uses the Data Pointer, DPTR, a 16-bit
register which contains the effective address of the XRAM location to be read from or written to. The second method uses R0 or R1 in combination with the EMI0CN register to generate the effective XRAM
address. Examples of both of these methods are given below.
15.1.1. 16-Bit MOVX Example
The 16-bit form of the MOVX instruction accesses the memory location pointed to by the contents of the
DPTR register. The following series of instructions reads the value of the byte at address 0x1234 into the
accumulator A:
MOV
MOVX
DPTR, #1234h
A, @DPTR
; load DPTR with 16-bit address to read (0x1234)
; load contents of 0x1234 into accumulator A
The above example uses the 16-bit immediate MOV instruction to set the contents of DPTR. Alternately,
the DPTR can be accessed through the SFR registers DPH, which contains the upper 8-bits of DPTR, and
DPL, which contains the lower 8-bits of DPTR.
15.1.2. 8-Bit MOVX Example
The 8-bit form of the MOVX instruction uses the contents of the EMI0CN SFR to determine the upper 8-bits
of the effective address to be accessed and the contents of R0 or R1 to determine the lower 8-bits of the
effective address to be accessed. The following series of instructions read the contents of the byte at
address 0x1234 into the accumulator A.
MOV
MOV
MOVX
154
EMI0CN, #12h
R0, #34h
a, @R0
; load high byte of address into EMI0CN
; load low byte of address into R0 (or R1)
; load contents of 0x1234 into accumulator A
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
15.2. Configuring the External Memory Interface
Configuring the External Memory Interface consists of five steps:
1. Configure the Output Modes of the associated port pins as either push-pull or open-drain
(push-pull is most common), and skip the associated pins in the crossbar.
2. Configure Port latches to “park” the EMIF pins in a dormant state (usually by setting them to
logic ‘1’).
3. Select Multiplexed mode or Non-multiplexed mode.
4. Select the memory mode (on-chip only, split mode without bank select, split mode with bank
select, or off-chip only).
5. Set up timing to interface with off-chip memory or peripherals.
Each of these five steps is explained in detail in the following sections. The Port selection, Multiplexed
mode selection, and Mode bits are located in the EMI0CF register shown in SFR Definition 15.2.
15.3. Port Configuration
The External Memory Interface appears on Ports 1, 2 (non-multiplexed mode only), 3, and 4 when it is
used for off-chip memory access. When the EMIF is used in multiplexed mode, the Crossbar should be
configured to skip over the ALE control line (P0.0) using the P0SKIP register. The other control lines, /RD
(P4.4) and /WR (P4.5), are not available on the Crossbar and do not need to be skipped. For more information about configuring the Crossbar, see Section “17.3. General Purpose Port I/O” on page 191. The
EMIF pinout is shown in Table 15.1 on page 156.
The External Memory Interface claims the associated Port pins for memory operations ONLY during the
execution of an off-chip MOVX instruction. Once the MOVX instruction has completed, control of the Port
pins reverts to the Port latches or to the Crossbar settings for those pins. See Section “17. Port Input/Output” on page 184 for more information about the Crossbar and Port operation and configuration. The Port
latches should be explicitly configured to ‘park’ the External Memory Interface pins in a dormant
state, most commonly by setting them to a logic ‘1’.
During the execution of the MOVX instruction, the External Memory Interface will explicitly disable the drivers on all Port pins that are acting as Inputs (Data[7:0] during a READ operation, for example). The Output
mode of the Port pins (whether the pin is configured as Open-Drain or Push-Pull) is unaffected by the
External Memory Interface operation, and remains controlled by the PnMDOUT registers. In most cases,
the output modes of all EMIF pins should be configured for push-pull mode.
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Table 15.1. EMIF Pinout (C8051F360/3)
Multiplexed Mode
Signal Name
/RD
/WR
ALE
D0/A0
D1/A1
D2/A2
D3/A3
D4/A4
D5/A5
D6/A6
D7/A7
A8
A9
A10
A11
A12
A13
A14
A15
–
–
–
–
–
–
–
–
Non Multiplexed Mode
Port Pin
P4.4
P4.5
P0.0
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P3.4
P3.5
P3.6
P3.7
P4.0
P4.1
P4.2
P4.3
–
–
–
–
–
–
–
–
Signal Name
/RD
/WR
ALE
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
Port Pin
P4.4
P4.5
P0.0
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
P3.4
P3.5
P3.6
P3.7
P4.0
P4.1
P4.2
P4.3
SFR Definition 15.1. EMI0CN: External Memory Interface Control
SFR Page:
all pages
SFR Address: 0xAA
R/W
R/W
R/W
R/W
R/W
R/W
R/W
PGSEL7
PGSEL6
PGSEL5
PGSEL4
PGSEL3
PGSEL2
PGSEL1
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
PGSEL0 00000000
Bit0
Bits 7–0: PGSEL[7:0]: XRAM Page Select Bits.
The XRAM Page Select Bits provide the high byte of the 16-bit external data memory
address when using an 8-bit MOVX command, effectively selecting a 256-byte page of
RAM.
0x00: 0x0000 to 0x00FF
0x01: 0x0100 to 0x01FF
...
0xFE: 0xFE00 to 0xFEFF
0xFF: 0xFF00 to 0xFFFF
156
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SFR Definition 15.2. EMI0CF: External Memory Configuration
SFR Page:
F
SFR Address: 0xC7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
–
–
–
EMD2
EMD1
EMD0
EALE1
EALE0
00000011
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–5: UNUSED. Read = 000b. Write = don’t care.
Bit 4:
EMD2: EMIF Multiplex Mode Select.
0: EMIF operates in multiplexed address/data mode.
1: EMIF operates in non-multiplexed mode (separate address and data pins).
Bits 3–2: EMD1–0: EMIF Operating Mode Select.
These bits control the operating mode of the External Memory Interface.
00: Internal Only: MOVX accesses on-chip XRAM only. All effective addresses alias to
on-chip memory space.
01: Split Mode without Bank Select: Accesses below the 1 k boundary are directed on-chip.
Accesses above the 1 k boundary are directed off-chip. 8-bit off-chip MOVX operations
use the current contents of the Address High port latches to resolve upper address byte.
Note that in order to access off-chip space, EMI0CN must be set to a page that is not
contained in the on-chip address space.
10: Split Mode with Bank Select: Accesses below the 1 k boundary are directed on-chip.
Accesses above the 1 k boundary are directed off-chip. 8-bit off-chip MOVX operations
use the contents of EMI0CN to determine the high-byte of the address.
11: External Only: MOVX accesses off-chip XRAM only. On-chip XRAM is not visible to the
CPU.
Bits 1–0: EALE1–0: ALE Pulse-Width Select Bits (only has effect when EMD2 = 0).
00: ALE high and ALE low pulse width = 1 SYSCLK cycle.
01: ALE high and ALE low pulse width = 2 SYSCLK cycles.
10: ALE high and ALE low pulse width = 3 SYSCLK cycles.
11: ALE high and ALE low pulse width = 4 SYSCLK cycles.
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15.4. Multiplexed and Non-multiplexed Selection
The External Memory Interface is capable of acting in a Multiplexed mode or a Non-multiplexed mode,
depending on the state of the EMD2 (EMI0CF.4) bit.
15.4.1. Multiplexed Configuration
In Multiplexed mode, the Data Bus and the lower 8-bits of the Address Bus share the same Port pins:
AD[7:0]. In this mode, an external latch (74HC373 or equivalent logic gate) is used to hold the lower 8-bits
of the RAM address. The external latch is controlled by the ALE (Address Latch Enable) signal, which is
driven by the External Memory Interface logic. An example of a Multiplexed Configuration is shown in
Figure 15.1.
In Multiplexed mode, the external MOVX operation can be broken into two phases delineated by the state
of the ALE signal. During the first phase, ALE is high and the lower 8-bits of the Address Bus are presented to AD[7:0]. During this phase, the address latch is configured such that the ‘Q’ outputs reflect the
states of the ‘D’ inputs. When ALE falls, signaling the beginning of the second phase, the address latch
outputs remain fixed and are no longer dependent on the latch inputs. Later in the second phase, the Data
Bus controls the state of the AD[7:0] port at the time /RD or /WR is asserted.
See Section “15.6.2. Multiplexed Mode” on page 166 for more information.
A[15:8]
A[15:8]
ADDRESS BUS
74HC373
E
M
I
F
G
ALE
AD[7:0]
D
ADDRESS/DATA BUS
Q
A[7:0]
VDD
64 K X 8
SRAM
(Optional)
8
I/O[7:0]
CE
WE
OE
/WR
/RD
Figure 15.1. Multiplexed Configuration Example
158
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15.4.2. Non-multiplexed Configuration
In Non-multiplexed mode, the Data Bus and the Address Bus pins are not shared. An example of a
Non-multiplexed Configuration is shown in Figure 15.2. See Section “15.6.1. Non-multiplexed Mode” on
page 163 for more information about Non-multiplexed operation.
E
M
I
F
A[15:0]
ADDRESS BUS
A[15:0]
VDD
(Optional)
8
D[7:0]
DATA BUS
64 K X 8
SRAM
I/O[7:0]
CE
WE
OE
/WR
/RD
Figure 15.2. Non-multiplexed Configuration Example
Rev. 1.2
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15.5. Memory Mode Selection
The external data memory space can be configured in one of four modes, shown in Figure 15.3, based on
the EMIF Mode bits in the EMI0CF register (SFR Definition 15.2). These modes are summarized below.
More information about the different modes can be found in Section “15.6. Timing” on page 161.
EMI0CF[3:2] = 00
EMI0CF[3:2] = 01
0xFFFF
EMI0CF[3:2] = 11
EMI0CF[3:2] = 10
0xFFFF
0xFFFF
0xFFFF
On-Chip XRAM
On-Chip XRAM
Off-Chip
Memory
(No Bank Select)
Off-Chip
Memory
(Bank Select)
On-Chip XRAM
Off-Chip
Memory
On-Chip XRAM
On-Chip XRAM
On-Chip XRAM
On-Chip XRAM
On-Chip XRAM
0x0000
0x0000
0x0000
0x0000
Figure 15.3. EMIF Operating Modes
15.5.1. Internal XRAM Only
When EMI0CF.[3:2] are set to ‘00’, all MOVX instructions will target the internal XRAM space on the
device. Memory accesses to addresses beyond the populated space will wrap on 1k boundaries. As an
example, the addresses 0x0400 and 0x1000 both evaluate to address 0x0000 in on-chip XRAM space.
•
•
8-bit MOVX operations use the contents of EMI0CN to determine the high-byte of the effective address
and R0 or R1 to determine the low-byte of the effective address.
16-bit MOVX operations use the contents of the 16-bit DPTR to determine the effective address.
15.5.2. Split Mode without Bank Select
When EMI0CF.[3:2] are set to ‘01’, the XRAM memory map is split into two areas, on-chip space and
off-chip space.
•
•
•
•
160
Effective addresses below the internal XRAM size boundary will access on-chip XRAM space.
Effective addresses above the internal XRAM size boundary will access off-chip space.
8-bit MOVX operations use the contents of EMI0CN to determine whether the memory access is
on-chip or off-chip. However, in the “No Bank Select” mode, an 8-bit MOVX operation will not drive the
upper 8-bits A[15:8] of the Address Bus during an off-chip access. This allows the user to manipulate
the upper address bits at will by setting the Port state directly via the port latches. This behavior is in
contrast with “Split Mode with Bank Select” described below. The lower 8-bits of the Address Bus
A[7:0] are driven, determined by R0 or R1.
16-bit MOVX operations use the contents of DPTR to determine whether the memory access is
on-chip or off-chip, and unlike 8-bit MOVX operations, the full 16-bits of the Address Bus A[15:0] are
driven during the off-chip transaction.
Rev. 1.2
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15.5.3. Split Mode with Bank Select
When EMI0CF.[3:2] are set to ‘10’, the XRAM memory map is split into two areas, on-chip space and
off-chip space.
•
•
•
•
Effective addresses below the internal XRAM size boundary will access on-chip XRAM space.
Effective addresses above the internal XRAM size boundary will access off-chip space.
8-bit MOVX operations use the contents of EMI0CN to determine whether the memory access is
on-chip or off-chip. The upper 8-bits of the Address Bus A[15:8] are determined by EMI0CN, and the
lower 8-bits of the Address Bus A[7:0] are determined by R0 or R1. All 16-bits of the Address Bus
A[15:0] are driven in “Bank Select” mode.
16-bit MOVX operations use the contents of DPTR to determine whether the memory access is
on-chip or off-chip, and the full 16-bits of the Address Bus A[15:0] are driven during the off-chip transaction.
15.5.4. External Only
When EMI0CF[3:2] are set to ‘11’, all MOVX operations are directed to off-chip space. On-chip XRAM is
not visible to the CPU. This mode is useful for accessing off-chip memory located between 0x0000 and the
internal XRAM size boundary.
•
•
8-bit MOVX operations ignore the contents of EMI0CN. The upper Address bits A[15:8] are not driven
(identical behavior to an off-chip access in “Split Mode without Bank Select” described above). This
allows the user to manipulate the upper address bits at will by setting the Port state directly. The lower
8-bits of the effective address A[7:0] are determined by the contents of R0 or R1.
16-bit MOVX operations use the contents of DPTR to determine the effective address A[15:0]. The full
16-bits of the Address Bus A[15:0] are driven during the off-chip transaction.
15.6. Timing
The timing parameters of the External Memory Interface can be configured to enable connection to
devices having different setup and hold time requirements. The Address Setup time, Address Hold time, /
RD and /WR strobe widths, and in multiplexed mode, the width of the ALE pulse are all programmable in
units of SYSCLK periods through EMI0TC, shown in SFR Definition 15.3, and EMI0CF[1:0].
The timing for an off-chip MOVX instruction can be calculated by adding 4 SYSCLK cycles to the timing
parameters defined by the EMI0TC register. Assuming non-multiplexed operation, the minimum execution
time for an off-chip XRAM operation is 5 SYSCLK cycles (1 SYSCLK for /RD or /WR pulse + 4 SYSCLKs).
For multiplexed operations, the Address Latch Enable signal will require a minimum of 2 additional
SYSCLK cycles. Therefore, the minimum execution time for an off-chip XRAM operation in multiplexed
mode is 7 SYSCLK cycles (2 for /ALE + 1 for /RD or /WR + 4). The programmable setup and hold times
default to the maximum delay settings after a reset. Table 15.2 lists the AC parameters for the External
Memory Interface, and Figure 15.4 through Figure 15.9 show the timing diagrams for the different External
Memory Interface modes and MOVX operations.
Rev. 1.2
161
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 15.3. EMI0TC: External Memory Timing Control
SFR Page:
F
SFR Address: 0xF7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
EAS1
EAS0
ERW3
EWR2
EWR1
EWR0
EAH1
EAH0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–6: EAS1–0: EMIF Address Setup Time Bits.
00: Address setup time = 0 SYSCLK cycles.
01: Address setup time = 1 SYSCLK cycle.
10: Address setup time = 2 SYSCLK cycles.
11: Address setup time = 3 SYSCLK cycles.
Bits 5–2: EWR3–0: EMIF /WR and /RD Pulse-Width Control Bits.
0000: /WR and /RD pulse width = 1 SYSCLK cycle.
0001: /WR and /RD pulse width = 2 SYSCLK cycles.
0010: /WR and /RD pulse width = 3 SYSCLK cycles.
0011: /WR and /RD pulse width = 4 SYSCLK cycles.
0100: /WR and /RD pulse width = 5 SYSCLK cycles.
0101: /WR and /RD pulse width = 6 SYSCLK cycles.
0110: /WR and /RD pulse width = 7 SYSCLK cycles.
0111: /WR and /RD pulse width = 8 SYSCLK cycles.
1000: /WR and /RD pulse width = 9 SYSCLK cycles.
1001: /WR and /RD pulse width = 10 SYSCLK cycles.
1010: /WR and /RD pulse width = 11 SYSCLK cycles.
1011: /WR and /RD pulse width = 12 SYSCLK cycles.
1100: /WR and /RD pulse width = 13 SYSCLK cycles.
1101: /WR and /RD pulse width = 14 SYSCLK cycles.
1110: /WR and /RD pulse width = 15 SYSCLK cycles.
1111: /WR and /RD pulse width = 16 SYSCLK cycles.
Bits 1–0: EAH1–0: EMIF Address Hold Time Bits.
00: Address hold time = 0 SYSCLK cycles.
01: Address hold time = 1 SYSCLK cycle.
10: Address hold time = 2 SYSCLK cycles.
11: Address hold time = 3 SYSCLK cycles.
162
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
15.6.1. Non-multiplexed Mode
15.6.1.1.16-bit MOVX: EMI0CF[4:2] = ‘101’, ‘110’, or ‘111’.
Nonmuxed 16-bit WRITE
ADDR[15:8]
P3.4–P4.3
EMIF ADDRESS (8 MSBs) from DPH
P3.4–P4.3
ADDR[7:0]
P2
EMIF ADDRESS (8 LSBs) from DPL
P2
DATA[7:0]
P1
EMIF WRITE DATA
P1
T
T
WDS
T
ACS
WDH
T
T
ACW
ACH
/WR
P4.5
P4.5
/RD
P4.4
P4.4
Nonmuxed 16-bit READ
ADDR[15:8]
P3.4–P4.3
EMIF ADDRESS (8 MSBs) from DPH
P3.4–P4.3
ADDR[7:0]
P2
EMIF ADDRESS (8 LSBs) from DPL
P2
DATA[7:0]
P1
EMIF READ DATA
P1
T
RDS
T
ACS
T
ACW
T
RDH
T
ACH
/RD
P4.4
P4.4
/WR
P4.5
P4.5
Figure 15.4. Non-multiplexed 16-bit MOVX Timing
Rev. 1.2
163
C8051F360/1/2/3/4/5/6/7/8/9
15.6.1.2.8-bit MOVX without Bank Select: EMI0CF[4:2] = ‘101’ or ‘111’.
Nonmuxed 8-bit WRITE without Bank Select
ADDR[15:8]
P3.4-P4.3
ADDR[7:0]
P2
EMIF ADDRESS (8 LSBs) from R0 or R1
P2
DATA[7:0]
P1
EMIF WRITE DATA
P1
T
T
WDS
WDH
T
T
ACS
T
ACW
ACH
/WR
P4.5
P4.5
/RD
P4.4
P4.4
Nonmuxed 8-bit READ without Bank Select
ADDR[15:8]
P3.4-P4.3
ADDR[7:0]
P2
DATA[7:0]
P1
EMIF ADDRESS (8 LSBs) from R0 or R1
EMIF READ DATA
T
RDS
T
T
ACS
ACW
P2
P1
T
RDH
T
ACH
/RD
P4.4
P4.4
/WR
P4.5
P4.5
Figure 15.5. Non-multiplexed 8-bit MOVX without Bank Select Timing
164
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
15.6.1.3.8-bit MOVX with Bank Select: EMI0CF[4:2] = ‘110’.
Nonmuxed 8-bit WRITE with Bank Select
ADDR[15:8]
P3.4–P4.3
EMIF ADDRESS (8 MSBs) from EMI0CN
P3.4–P4.3
ADDR[7:0]
P2
EMIF ADDRESS (8 LSBs) from R0 or R1
P2
DATA[7:0]
P1
EMIF WRITE DATA
P1
T
T
WDS
T
ACS
WDH
T
T
ACW
ACH
/WR
P4.5
P4.5
/RD
P4.4
P4.4
Nonmuxed 8-bit READ with Bank Select
ADDR[15:8]
P3.4–P4.3
EMIF ADDRESS (8 MSBs) from EMI0CN
P3.4–P4.3
ADDR[7:0]
P2
EMIF ADDRESS (8 LSBs) from R0 or R1
P2
DATA[7:0]
P1
EMIF READ DATA
T
RDS
T
ACS
T
ACW
P1
T
RDH
T
ACH
/RD
P4.4
P4.4
/WR
P4.5
P4.5
Figure 15.6. Non-multiplexed 8-bit MOVX with Bank Select Timing
Rev. 1.2
165
C8051F360/1/2/3/4/5/6/7/8/9
15.6.2. Multiplexed Mode
15.6.2.1.16-bit MOVX: EMI0CF[4:2] = ‘001’, ‘010’, or ‘011’.
Muxed 16-bit WRITE
ADDR[15:8]
AD[7:0]
P3.4–P4.3
P1
EMIF ADDRESS (8 MSBs) from DPH
EMIF ADDRESS (8 LSBs) from
DPL
T
ALEH
ALE
P3.4–P4.3
EMIF WRITE DATA
P1
T
ALEL
P0.0
P0.0
T
T
WDS
T
ACS
WDH
T
T
ACW
ACH
/WR
P4.5
P4.5
/RD
P4.4
P4.4
Muxed 16-bit READ
ADDR[15:8]
AD[7:0]
P3.4–P4.3
P1
EMIF ADDRESS (8 MSBs) from DPH
EMIF ADDRESS (8 LSBs) from
DPL
T
ALEH
ALE
P3.4–P4.3
EMIF READ DATA
T
T
ALEL
RDS
T
RDH
P0.0
P0.0
T
ACS
T
ACW
T
ACH
/RD
P4.4
P4.4
/WR
P4.5
P4.5
Figure 15.7. Multiplexed 16-bit MOVX Timing
166
P1
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
15.6.2.2.8-bit MOVX without Bank Select: EMI0CF[4:2] = ‘001’ or ‘011’.
Muxed 8-bit WRITE Without Bank Select
ADDR[15:8]
AD[7:0]
P3.4–P4.3
P1
EMIF ADDRESS (8 LSBs) from
R0 or R1
T
ALEH
ALE
EMIF WRITE DATA
P1
T
ALEL
P0.0
P0.0
T
T
WDS
T
ACS
WDH
T
T
ACW
ACH
/WR
P4.5
P4.5
/RD
P4.4
P4.4
Muxed 8-bit READ Without Bank Select
ADDR[15:8]
AD[7:0]
P3.4–P4.3
P1
EMIF ADDRESS (8 LSBs) from
R0 or R1
T
ALEH
ALE
EMIF READ DATA
T
T
ALEL
RDS
P1
T
RDH
P0.0
P0.0
T
ACS
T
ACW
T
ACH
/RD
P4.4
P4.4
/WR
P4.5
P4.5
Figure 15.8. Multiplexed 8-bit MOVX without Bank Select Timing
Rev. 1.2
167
C8051F360/1/2/3/4/5/6/7/8/9
15.6.2.3.8-bit MOVX with Bank Select: EMI0CF[4:2] = ‘010’.
Muxed 8-bit WRITE with Bank Select
ADDR[15:8]
AD[7:0]
P3.4–P4.3
P1
EMIF ADDRESS (8 MSBs) from EMI0CN
EMIF ADDRESS (8 LSBs) from
R0 or R1
T
ALEH
ALE
P3.4–P4.3
EMIF WRITE DATA
P1
T
ALEL
P0.0
P0.0
T
T
WDS
T
ACS
WDH
T
T
ACW
ACH
/WR
P4.5
P4.5
/RD
P4.4
P4.4
Muxed 8-bit READ with Bank Select
ADDR[15:8]
AD[7:0]
P3.4–P4.3
P1
EMIF ADDRESS (8 MSBs) from EMI0CN
EMIF ADDRESS (8 LSBs) from
R0 or R1
T
ALEH
ALE
P3.4–P4.3
EMIF READ DATA
T
T
ALEL
RDS
T
RDH
P0.0
P0.0
T
ACS
T
ACW
T
ACH
/RD
P4.4
P4.4
/WR
P4.5
P4.5
Figure 15.9. Multiplexed 8-bit MOVX with Bank Select Timing
168
P1
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Table 15.2. AC Parameters for External Memory Interface
Parameter
Description
Min*
Max*
Units
TACS
Address/Control Setup Time
0
3 x TSYSCLK
ns
TACW
Address/Control Pulse Width
1 x TSYSCLK
16 x TSYSCLK
ns
TACH
Address/Control Hold Time
0
3 x TSYSCLK
ns
TALEH
Address Latch Enable High Time
1 x TSYSCLK
4 x TSYSCLK
ns
TALEL
Address Latch Enable Low Time
1 x TSYSCLK
4 x TSYSCLK
ns
TWDS
Write Data Setup Time
1 x TSYSCLK
19 x TSYSCLK
ns
TWDH
Write Data Hold Time
0
3 x TSYSCLK
ns
TRDS
Read Data Setup Time
20
ns
TRDH
Read Data Hold Time
0
ns
*Note: TSYSCLK is equal to one period of the device system clock (SYSCLK).
Rev. 1.2
169
C8051F360/1/2/3/4/5/6/7/8/9
16. Oscillators
The C8051F36x devices include a programmable internal high-frequency oscillator, a programmable internal low-frequency oscillator, and an external oscillator drive circuit. The internal high-frequency oscillator
can be enabled, disabled, and calibrated using the OSCICN and OSCICL registers, as shown in
Figure 16.1. The internal low-frequency oscillator can be enabled/disabled and calibrated using the
OSCLCN register, as shown in SFR Definition 16.3. Both internal oscillators offer a selectable post-scaling
feature. The system clock can be sourced by the external oscillator circuit, either internal oscillator, or the
on-chip phase-locked loop (PLL). The internal oscillator's electrical specifications are given in Table 16.1
on page 172 and Table 16.2 on page 173.
IFCN1
IFCN0
OSCLCN
OSCLEN
OSCLRDY
OSCLF3
OSCLF2
OSCLF1
OSCLF0
OSCLD1
OSCLD0
OSCICN
IOSCEN
IFRDY
SUSPEND
OSCICL
AV+
OSCLF OSCLD
EN
Option 2
VDD
Calibrated Internal
Oscillator
Option 1
n
000
XTAL1
Input
Circuit
XTAL2
OSC
001
XTAL2
SYSCLK
Option 3
XTAL2
Option 4
XTAL2
n
OSCLF
EN
Low Frequency
Oscillator
010
OSCLD
100
PLL
OSCXCN
CLKSL2
CLKSL1
CLKSL0
CLKDIV1
CLKDIV0
XFCN2
XFCN1
XFCN0
XTLVLD
XOSCMD2
XOSCMD1
XOSCMD0
AGND
CLKSEL
Figure 16.1. Oscillator Diagram
16.1. Programmable Internal High-Frequency (H-F) Oscillator
All devices include a calibrated internal high-frequency oscillator that defaults as the system clock after a
system reset. The internal oscillator period can be adjusted via the OSCICL register as defined by SFR
Definition 16.1. OSCICL is factory calibrated to obtain a 24.5 MHz frequency.
Electrical specifications for the precision internal oscillator are given in Table 16.1 on page 172 and
Table 16.2 on page 173. Note that the system clock may be derived from the programmed internal oscillator divided by 1, 2, 4, or 8, as defined by the IFCN bits in register OSCICN. The divide value defaults to 8
following a reset.
170
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
16.1.1. Internal Oscillator Suspend Mode
When software writes a logic ‘1’ to SUSPEND (OSCICN.5), the internal oscillator is suspended. If the system clock is derived from the internal oscillator, the input clock to the peripheral or CIP-51 will be stopped
until one of the following events occur:
•
•
•
•
•
Port 0 Match Event.
Port 1 Match Event.
Port 2 Match Event.
Comparator 0 enabled and output is logic ‘0’.
Comparator 1 enabled and output is logic ‘0’.
When one of the internal oscillator awakening events occur, the internal oscillator, CIP-51, and affected
peripherals resume normal operation, regardless of whether the event also causes an interrupt. The CPU
resumes execution at the instruction following the write to SUSPEND.
Note: Before entering SUSPEND mode, SYSCLK should be switched to run off of the internal oscillator
and not the PLL. When the CPU wakes due to the awakening event, the PLL must be reinitialized before
switching back to it as the SYSCLK source.
SFR Definition 16.1. OSCICL: Internal Oscillator Calibration.
SFR Page:
F
SFR Address: 0xBF
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
Variable
Bits 7–0: OSCICL: Internal Oscillator Calibration Register.
This register calibrates the internal oscillator period. The reset value for OSCICL defines the
internal oscillator base frequency. The reset value is factory calibrated to generate an internal oscillator frequency of 24.5 MHz.
Rev. 1.2
171
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 16.2. OSCICN: Internal Oscillator Control
SFR Page:
F
SFR Address: 0xB7
R/W
R
IOSCEN
IFRDY
Bit7
Bit6
R/W
R
R/W
R/W
SUSPEND Reserved Reserved Reserved
Bit5
Bit4
Bit3
Bit2
R/W
R/W
Reset Value
IFCN1
IFCN0
11000000
Bit1
Bit0
Bit 7:
IOSCEN: Internal Oscillator Enable Bit.
0: Internal Oscillator Disabled.
1: Internal Oscillator Enabled.
Bit 6:
IFRDY: Internal Oscillator Frequency Ready Flag.
0: Internal Oscillator not running at programmed frequency.
1: Internal Oscillator running at programmed frequency.
Bits 5:
SUSPEND: Internal Oscillator Suspend Enable Bit.
Setting this bit to logic ‘1’ places the internal oscillator in SUSPEND mode. The internal
oscillator resumes operation when one of the SUSPEND mode awakening events occur.
Bits 4–2: RESERVED. Read = 000b. Must Write 000b.
Bits 1–0: IFCN1-0: Internal Oscillator Frequency Control Bits.
00: Internal Oscillator is divided by 8. (default)
01: Internal Oscillator is divided by 4.
10: Internal Oscillator is divided by 2.
11: Internal Oscillator is divided by 1.
Table 16.1. Internal High Frequency Oscillator Electrical Characteristics
–40°C to +85°C unless otherwise specified.
Parameter
Conditions
Calibrated Internal Oscillator
Frequency
Internal Oscillator Supply
OSCICN.7 = 1
Current (from VDD)
Power Supply Sensitivity
Constant Temperature
Temperature Sensitivity
Constant Supply
External Clock Frequency
TXCH (External Clock High Time)
TXCL (External Clock Low Time)
Min
Typ
Max
Units
24
24.5
25
MHz
—
450
600
µA
—
—
0
15
15
0.12
60
—
—
—
—
—
30
—
—
%/V
ppm/°C
MHz
ns
ns
16.2. Programmable Internal Low-Frequency (L-F) Oscillator
All C8051F36x devices include a programmable low-frequency internal oscillator, which is calibrated to a
nominal frequency of 80 kHz. The low-frequency oscillator circuit includes a divider that can be changed to
divide the clock by 1, 2, 4, or 8, using the OSCLD bits in the OSCLCN register (see SFR Definition 16.3).
Additionally, the OSCLF bits (OSCLCN5:2) can be used to adjust the oscillator’s output frequency.
172
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
16.2.1. Calibrating the Internal L-F Oscillator
Timers 2 and 3 include capture functions that can be used to capture the oscillator frequency, when running from a known time base. When either Timer 2 or Timer 3 is configured for L-F Oscillator Capture
Mode, a falling edge (Timer 2) or rising edge (Timer 3) of the low-frequency oscillator’s output will cause a
capture event on the corresponding timer. As a capture event occurs, the current timer value
(TMRnH:TMRnL) is copied into the timer reload registers (TMRnRLH:TMRnRLL). By recording the difference between two successive timer capture values, the low-frequency oscillator’s period can be calculated. The OSCLF bits can then be adjusted to produce the desired oscillator frequency.
SFR Definition 16.3. OSCLCN: Internal L-F Oscillator Control
SFR Page:
F
SFR Address: 0xAD
R/W
R
R/W
OSCLEN OSCLRDY OSCLF3
Bit7
Bit6
R/W
R/W
R/W
R/W
R/W
Reset Value
OSCLF2
OSCLF1
OSCLF0
OSCLD1
OSCLD0
00vvvv00
Bit4
Bit3
Bit2
Bit1
Bit0
Bit5
Bit 7:
OSCLEN: Internal L-F Oscillator Enable.
0: Internal L-F Oscillator Disabled.
1: Internal L-F Oscillator Enabled.
Bit 6:
OSCLRDY: Internal L-F Oscillator Ready.
0: Internal L-F Oscillator frequency not stabilized.
1: Internal L-F Oscillator frequency stabilized.
Bits 5–2: OSCLF[3:0]: Internal L-F Oscillator Frequency Control bits.
Fine-tune control bits for the Internal L-F oscillator frequency. When set to 0000b, the L-F
oscillator operates at its fastest setting. When set to 1111b, the L-F oscillator operates at its
slowest setting.
Bits 1–0: OSCLD[1:0]: Internal L-F Oscillator Divider Select.
00: Divide by 8 selected.
01: Divide by 4 selected.
10: Divide by 2 selected.
11: Divide by 1 selected.
Table 16.2. Internal Low Frequency Oscillator Electrical Characteristics
–40°C to +85°C unless otherwise specified.
Parameter
Oscillator Frequency
Conditions
OSCLD = 11b
25 °C, VDD = 3.0 V,
Oscillator Supply Current (from VDD)
OSCLCN.7 = 1
Power Supply Sensitivity
Constant Temperature
Temperature Sensitivity
Constant Supply
Rev. 1.2
Min
72
Typ
80
Max
88
Units
kHz
—
5.5
10
µA
—
—
2.4
30
—
—
%/V
ppm/°C
173
C8051F360/1/2/3/4/5/6/7/8/9
16.3. External Oscillator Drive Circuit
The external oscillator circuit may drive an external crystal, ceramic resonator, capacitor, or RC network. A
CMOS clock may also provide a clock input. For a crystal or ceramic resonator configuration, the crystal/
resonator must be wired across the XTAL1 and XTAL2 pins as shown in Option 1 of Figure 16.1. A 10 M
resistor also must be wired across the XTAL1 and XTAL2 pins for the crystal/resonator configuration. In
RC, capacitor, or CMOS clock configuration, the clock source should be wired to the XTAL2 pin as shown
in Option 2, 3, or 4 of Figure 16.1. The type of external oscillator must be selected in the OSCXCN register,
and the frequency control bits (XFCN) must be selected appropriately (see SFR Definition 16.5).
Important Note on External Oscillator Usage: Port pins must be configured when using the external
oscillator circuit. When the external oscillator drive circuit is enabled in crystal/resonator mode, Port pins
P0.5 and P0.6 (C8051F360/3) or P0.2 and P0.3 (C8051F361/2/4/5/6/7/8/9) are used as XTAL1 and XTAL2
respectively. When the external oscillator drive circuit is enabled in capacitor, RC, or CMOS clock mode,
Port pin P0.6 (C8051F360/3) or P0.3 (C8051F361/2/4/5/6/7/8/9) is used as XTAL2. The Port I/O Crossbar
should be configured to skip the Port pins used by the oscillator circuit; see Section “17.1. Priority Crossbar
Decoder” on page 186 for Crossbar configuration. Additionally, when using the external oscillator circuit in
crystal/resonator, capacitor, or RC mode, the associated Port pins should be configured as analog inputs.
In CMOS clock mode, the associated pin should be configured as a digital input. See Section “17.2. Port
I/O Initialization” on page 188 for details on Port input mode selection.
16.4. System Clock Selection
The internal oscillator requires little start-up time, and may be enabled and selected as the system clock in
the same write to OSCICN. External crystals and ceramic resonators typically require a start-up time
before they are settled and ready for use as the system clock. The Crystal Valid Flag (XTLVLD in register
OSCXCN) is set to ‘1’ by hardware when the external oscillator is settled. To avoid reading a false
XTLVLD, in crystal mode software should delay at least 1 ms between enabling the external oscillator and
checking XTLVLD. RC and C modes typically require no startup time. The PLL also requires time to lock
onto the desired frequency, and the PLL Lock Flag (PLLLCK in register PLL0CN) is set to ‘1’ by hardware
once the PLL is locked on the correct frequency.
The CLKSL1-0 bits in register CLKSEL select which oscillator source generates the system clock. CLKSL1-0 must be set to ‘01’ for the system clock to run from the external oscillator; however the external
oscillator may still clock certain peripherals, such as the timers and PCA, when the internal oscillator or the
PLL is selected as the system clock. The system clock may be switched on-the-fly between the internal
and external oscillators or the PLL, so long as the selected oscillator source is enabled and settled.
174
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 16.4. CLKSEL: System Clock Selection
SFR Page:
F
SFR Address: 0x8F
R/W
R/W
R/W
R/W
R/W
Reserved Reserved CLKDIV1 CLKDIV0 Reserved
Bit7
Bit6
Bit5
Bit4
R/W
R/W
CLKSL2
CLKSL1
Bit2
Bit1
Bit3
R/W
Reset Value
CLKSL0 00000000
Bit0
Bits 7–6: RESERVED. Read = 00b. Must Write 00b.
Bits 5–4: CLKDIV1-0: Output SYSCLK Divide Factor.
These bits can be used to pre-divide SYSCLK before it is output to a port pin through the
crossbar.
00: Output will be SYSCLK.
01: Output will be SYSCLK/2.
10: Output will be SYSCLK/4.
11: Output will be SYSCLK/8.
See Section “17. Port Input/Output” on page 184 for more details about routing this output to
a port pin.
Bit 3:
RESERVED. Read = 0b. Must Write 0b.
Bits 2–0: CLKSL2–0: System Clock Source Select Bits.
000: SYSCLK derived from the high-frequency Internal Oscillator, and scaled as per the
IFCN bits in OSCICN.
001: SYSCLK derived from the External Oscillator circuit.
010: SYSCLK derived from the low-frequency Internal Oscillator, and scaled as per the
OSCLD bits in OSCLCN.
011: RESERVED.
100: SYSCLK derived from the PLL.
101-11x: RESERVED.
Rev. 1.2
175
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 16.5. OSCXCN: External Oscillator Control
SFR Page:
F
SFR Address: 0xB6
R
R/W
R/W
R/W
R
XTLVLD XOSCMD2 XOSCMD1 XOSCMD0 Reserved
Bit7
Bit6
Bit5
Bit4
Bit3
R/W
R/W
R/W
Reset Value
XFCN2
XFCN1
XFCN0
00000000
Bit2
Bit1
Bit0
Bit 7:
XTLVLD: Crystal Oscillator Valid Flag.
(Valid only when XOSCMD = 11x.)
0: Crystal Oscillator is unused or not yet stable.
1: Crystal Oscillator is running and stable.
Bits 6–4: XOSCMD2–0: External Oscillator Mode Bits.
00x: External Oscillator circuit off.
010: External CMOS Clock Mode.
011: External CMOS Clock Mode with divide by 2 stage.
100: RC Oscillator Mode.
101: Capacitor Oscillator Mode.
110: Crystal Oscillator Mode.
111: Crystal Oscillator Mode with divide by 2 stage.
Bit 3:
RESERVED. Read = 0b. Write = don't care.
Bits 2–0: XFCN2–0: External Oscillator Frequency Control Bits.
000-111: see table below:
XFCN
000
001
010
011
100
101
110
111
Crystal (XOSCMD = 11x)
f 32 kHz
32 kHz f 84 kHz
84 kHz f 225 kHz
225 kHz f 590 kHz
590 kHz f 1.5 MHz
1.5 MHz f 4 MHz
4 MHz f 10 MHz
10 MHz f 30 MHz
RC (XOSCMD = 100)
f 25 kHz
25 kHz f 50 kHz
50 kHz f 100 kHz
100 kHz f 200 kHz
200 kHz f 400 kHz
400 kHz f 800 kHz
800 kHz f 1.6 MHz
1.6 MHz f 3.2 MHz
CRYSTAL MODE (Circuit from Figure 16.1, Option 1; XOSCMD = 11x)
Choose XFCN value to match crystal frequency.
RC MODE (Circuit from Figure 16.1, Option 2; XOSCMD = 10x)
Choose XFCN value to match frequency range:
f = 1.23(103)/(R * C), where
f = frequency of oscillation in MHz
C = capacitor value in pF
R = Pullup resistor value in k
C MODE (Circuit from Figure 16.1, Option 3; XOSCMD = 10x)
Choose K Factor (KF) for the oscillation frequency desired:
f = KF/(C * VDD), where
f = frequency of oscillation in MHz
C = capacitor value on XTAL1, XTAL2 pins in pF
VDD = Power Supply on MCU in Volts
176
Rev. 1.2
C (XOSCMD = 101)
K Factor = 0.87
K Factor = 2.6
K Factor = 7.7
K Factor = 22
K Factor = 65
K Factor = 180
K Factor = 664
K Factor = 1590
C8051F360/1/2/3/4/5/6/7/8/9
16.5. External Crystal Example
If a crystal or ceramic resonator is used as an external oscillator source for the MCU, the circuit should be
configured as shown in Figure 16.1, Option 1. The External Oscillator Frequency Control value (XFCN)
should be chosen from the Crystal column of the table in SFR Definition 16.5 (OSCXCN register). For
example, an 11.0592 MHz crystal requires an XFCN setting of 111b.
When the crystal oscillator is enabled, the oscillator amplitude detection circuit requires a settle time to
achieve proper bias. Waiting at least 1 ms between enabling the oscillator and checking the XTLVLD bit
will prevent a premature switch to the external oscillator as the system clock. Switching to the external
oscillator before the crystal oscillator has stabilized can result in unpredictable behavior. The recommended procedure is:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Force the XTAL1 and XTAL2 pins low by writing 0's to the port latch.
Configure XTAL1 and XTAL2 as analog inputs.
Enable the external oscillator.
Wait at least 1 ms.
Poll for XTLVLD => '1'.
Switch the system clock to the external oscillator.
Note: Tuning-fork crystals may require additional settling time before XTLVLD returns a valid result.
The capacitors shown in the external crystal configuration provide the load capacitance required by the
crystal for correct oscillation. These capacitors are "in series" as seen by the crystal and "in parallel" with
the stray capacitance of the XTAL1 and XTAL2 pins.
Note: The load capacitance depends upon the crystal and the manufacturer. Please refer to the crystal
data sheet when completing these calculations.
For example, a tuning-fork crystal of 32.768 kHz with a recommended load capacitance of 12.5 pF should
use the configuration shown in Figure 16.1, Option 1. The total value of the capacitors and the stray capacitance of the XTAL pins should equal 25 pF. With a stray capacitance of 3 pF per pin, the 22 pF capacitors
yield an equivalent capacitance of 12.5 pF across the crystal, as shown in Figure 16.2.
22 pF
XTAL 1
32.768 kHz
10 M
XTAL2
22 pF
Figure 16.2. 32.768 kHz External Crystal Example
Important Note on External Crystals: Crystal oscillator circuits are quite sensitive to PCB layout. The
crystal should be placed as close as possible to the XTAL pins on the device. The traces should be as
short as possible and shielded with ground plane from any other traces which could introduce noise or
interference.
Rev. 1.2
177
C8051F360/1/2/3/4/5/6/7/8/9
16.6. External RC Example
If an RC network is used as an external oscillator source for the MCU, the circuit should be configured as
shown in Figure 16.1, Option 2. The capacitor should be no greater than 100 pF; however for very small
capacitors, the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, first
select the RC network value to produce the desired frequency of oscillation. If the frequency desired is
100 kHz, let R = 246 k and C = 50 pF:
f = 1.23(103)/RC = 1.23 (103)/[246 x 50] = 0.1 MHz = 100 kHz
Referring to the table in SFR Definition 16.5, the required XFCN setting is 010b. Programming XFCN to a
higher setting in RC mode will improve frequency accuracy at a slightly increased external oscillator supply
current.
16.7. External Capacitor Example
If a capacitor is used as an external oscillator for the MCU, the circuit should be configured as shown in
Figure 16.1, Option 3. The capacitor should be no greater than 100 pF; however for very small capacitors,
the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the
required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, select the capacitor to be used and find the frequency of oscillation from the equations below. Assume VDD = 3.0 V and
f = 75 kHz:
f = KF / (C x VDD)
0.075 MHz = KF / (C x 3.0)
Since the frequency of roughly 75 kHz is desired, select the K Factor from the table in SFR Definition 16.5
as KF = 7.7:
0.075 MHz = 7.7 / (C x 3.0)
C x 3.0 = 7.7 / 0.075 MHz
C = 102.6 / 3.0 pF = 34.2 pF
Therefore, the XFCN value to use in this example is 010b.
178
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
16.8. Phase-Locked Loop (PLL)
A Phase-Locked-Loop (PLL) is included, which is used to multiply the internal oscillator or an external
clock source to achieve higher CPU operating frequencies. The PLL circuitry is designed to produce an
output frequency between 25 MHz and 100 MHz, from a divided reference frequency between 5 MHz and
30 MHz. A block diagram of the PLL is shown in Figure 16.3.
External
Oscillator
Divided
Reference
Clock
0
1
PLLICO1
PLLICO0
PLLLP3
PLLLP2
PLLLP1
PLLLP0
PLLLCK
Internal
Oscillator
PLL0FLT
PLLSRC
PLLEN
PLLPWR
PLL0CN
Phase /
Frequency
Detection
Loop Filter
Current
Controlled
Oscillator
PLL Clock
Output
PLLN7
PLLN6
PLLN5
PLLN4
PLLN3
PLLN2
PLLN1
PLLN0
PLLM4
PLLM3
PLLM2
PLLM1
PLLM0
PLL0DIV
PLL0MUL
Figure 16.3. PLL Block Diagram
16.8.1. PLL Input Clock and Pre-divider
The PLL circuitry can derive its reference clock from either the internal oscillator or an external clock
source. The PLLSRC bit (PLL0CN.2) controls which clock source is used for the reference clock (see SFR
Definition 16.6). If PLLSRC is set to ‘0’, the internal oscillator source is used. Note that the internal oscillator divide factor (as specified by bits IFCN1-0 in register OSCICN) will also apply to this clock. When PLLSRC is set to ‘1’, an external oscillator source will be used. The external oscillator should be active and
settled before it is selected as a reference clock for the PLL circuit. The reference clock is divided down
prior to the PLL circuit, according to the contents of the PLLM4-0 bits in the PLL Pre-divider Register
(PLL0DIV), shown in SFR Definition 16.7.
16.8.2. PLL Multiplication and Output Clock
The PLL circuitry will multiply the divided reference clock by the multiplication factor stored in the
PLL0MUL register shown in SFR Definition 16.8. To accomplish this, it uses a feedback loop consisting of
a phase/frequency detector, a loop filter, and a current-controlled oscillator (ICO). It is important to configure the loop filter and the ICO for the correct frequency ranges. The PLLLP3–0 bits (PLL0FLT.3–0) should
be set according to the divided reference clock frequency. Likewise, the PLLICO1–0 bits (PLL0FLT.5–4)
should be set according to the desired output frequency range. SFR Definition 16.9 describes the proper
settings to use for the PLLLP3–0 and PLLICO1–0 bits. When the PLL is locked and stable at the desired
frequency, the PLLLCK bit (PLL0CN.5) will be set to a ‘1’. The resulting PLL frequency will be set according to the equation:
PLLN
PLL Frequency = Reference Frequency --------------PLLM
Where “Reference Frequency” is the selected source clock frequency, PLLN is the PLL Multiplier, and
PLLM is the PLL Pre-divider.
Rev. 1.2
179
C8051F360/1/2/3/4/5/6/7/8/9
16.8.3. Powering on and Initializing the PLL
To set up and use the PLL as the system clock after power-up of the device, the following procedure
should be implemented:
Step 1. Ensure that the reference clock to be used (internal or external) is running and stable.
Step 2. Set the PLLSRC bit (PLL0CN.2) to select the desired clock source for the PLL.
Step 3. Program the Flash read timing bits, FLRT (FLSCL.5–4) to the appropriate value for the
new clock rate (see Section “13. Flash Memory” on page 136).
Step 4. Enable power to the PLL by setting PLLPWR (PLL0CN.0) to ‘1’.
Step 5. Program the PLL0DIV register to produce the divided reference frequency to the PLL.
Step 6. Program the PLLLP3–0 bits (PLL0FLT.3–0) to the appropriate range for the divided
reference frequency.
Step 7. Program the PLLICO1–0 bits (PLL0FLT.5–4) to the appropriate range for the PLL output
frequency.
Step 8. Program the PLL0MUL register to the desired clock multiplication factor.
Step 9. Wait at least 5 µs, to provide a fast frequency lock.
Step 10. Enable the PLL by setting PLLEN (PLL0CN.1) to ‘1’.
Step 11. Poll PLLLCK (PLL0CN.4) until it changes from ‘0’ to ‘1’.
Step 12. Switch the System Clock source to the PLL using the CLKSEL register.
If the PLL characteristics need to be changed when the PLL is already running, the following procedure
should be implemented:
Step 1. The system clock should first be switched to either the internal oscillator or an external
clock source that is running and stable, using the CLKSEL register.
Step 2. Ensure that the reference clock to be used for the new PLL setting (internal or external) is
running and stable.
Step 3. Set the PLLSRC bit (PLL0CN.2) to select the new clock source for the PLL.
Step 4. If moving to a faster frequency, program the Flash read timing bits, FLRT (FLSCL.5–4) to
the appropriate value for the new clock rate (see Section “13. Flash Memory” on
page 136).
Step 5. Disable the PLL by setting PLLEN (PLL0CN.1) to ‘0’.
Step 6. Program the PLL0DIV register to produce the divided reference frequency to the PLL.
Step 7. Program the PLLLP3–0 bits (PLL0FLT.3–0) to the appropriate range for the divided
reference frequency.
Step 8. Program the PLLICO1-0 bits (PLL0FLT.5–4) to the appropriate range for the PLL output
frequency.
Step 9. Program the PLL0MUL register to the desired clock multiplication factor.
Step 10. Enable the PLL by setting PLLEN (PLL0CN.1) to ‘1’.
Step 11. Poll PLLLCK (PLL0CN.4) until it changes from ‘0’ to ‘1’.
Step 12. Switch the System Clock source to the PLL using the CLKSEL register.
Step 13. If moving to a slower frequency, program the Flash read timing bits, FLRT (FLSCL.5–4)
to the appropriate value for the new clock rate (see Section “13. Flash Memory” on
page 136). Important Note: Cache reads, cache writes, and the prefetch engine
should be disabled whenever the FLRT bits are changed to a lower setting.
180
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
To shut down the PLL, the system clock should be switched to the internal oscillator or a stable external
clock source, using the CLKSEL register. Next, disable the PLL by setting PLLEN (PLL0CN.1) to ‘0’.
Finally, the PLL can be powered off, by setting PLLPWR (PLL0CN.0) to ‘0’. Note that the PLLEN and PLLPWR bits can be cleared at the same time.
SFR Definition 16.6. PLL0CN: PLL Control
SFR Page:
F
SFR Address: 0xB3
R/W
R/W
R/W
R
R/W
R/W
R/W
–
–
–
PLLLCK
Reserved
PLLSRC
PLLEN
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
PLLPWR 00000000
Bit0
Bits 7–5: UNUSED. Read = 000b. Write = don’t care.
Bit 4:
PLLLCK: PLL Lock Flag.
0: PLL Frequency is not locked.
1: PLL Frequency is locked.
Bit 3:
RESERVED. Read = 0b. Must Write 0b.
Bit 2:
PLLSRC: PLL Reference Clock Source Select Bit.
0: PLL Reference Clock Source is Internal Oscillator.
1: PLL Reference Clock Source is External Oscillator.
Bit 1:
PLLEN: PLL Enable Bit.
0: PLL is held in reset.
1: PLL is enabled. PLLPWR must be ‘1’.
Bit 0:
PLLPWR: PLL Power Enable.
0: PLL bias generator is de-activated. No static power is consumed.
1: PLL bias generator is active. Must be set for PLL to operate.
SFR Definition 16.7. PLL0DIV: PLL Pre-divider
SFR Page:
F
SFR Address: 0xA9
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000001
–
–
–
PLLM4
PLLM3
PLLM2
PLLM1
PLLM0
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–5: UNUSED. Read = 000b. Write = don’t care.
Bits 4–0: PLLM4–0: PLL Reference Clock Pre-divider.
These bits select the pre-divide value of the PLL reference clock. When set to any non-zero
value, the reference clock will be divided by the value in PLLM4–0. When set to ‘00000b’,
the reference clock will be divided by 32.
Rev. 1.2
181
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 16.8. PLL0MUL: PLL Clock Scaler
SFR Page:
F
SFR Address: 0xB1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
PLLN7
PLLN6
PLLN5
PLLN4
PLLN3
PLLN2
PLLN1
PLLN0
00000001
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: PLLN7–0: PLL Multiplier.
These bits select the multiplication factor of the divided PLL reference clock. When set to
any non-zero value, the multiplication factor will be equal to the value in PLLN7-0. When set
to ‘00000000b’, the multiplication factor will be equal to 256.
SFR Definition 16.9. PLL0FLT: PLL Filter
SFR Page:
F
SFR Address: 0xB2
R/W
R/W
–
–
Bit7
Bit6
R/W
R/W
PLLICO1 PLLICO0
Bit5
Bit4
R/W
R/W
R/W
R/W
Reset Value
PLLLP3
PLLLP2
PLLLP1
PLLLP0
00110001
Bit3
Bit2
Bit1
Bit0
Bits 7–6: UNUSED. Read = 00b. Write = don’t care.
Bits 5–4: PLLICO1-0: PLL Current-Controlled Oscillator Control Bits.
Selection is based on the desired output frequency, according to the following table:
PLL Output Clock
65–100 MHz
45–80 MHz
30–60 MHz
25–50 MHz
PLLICO1-0
00
01
10
11
Bits 3–0: PLLLP3-0: PLL Loop Filter Control Bits.
Selection is based on the divided PLL reference clock, according to the following table:
Divided PLL Reference Clock
19–30 MHz
12.2–19.5 MHz
7.8–12.5 MHz
5–8 MHz
PLLLP3-0
0001
0011
0111
1111
All other states of PLLLP3–0 are RESERVED.
182
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Table 16.3. PLL Frequency Characteristics
–40 to +85 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
Input Frequency
(Divided Reference Frequency)
5
30
MHz
PLL Output Frequency
25
100*
MHz
Max
Units
*Note: The maximum operating frequency of the C8051F366/7/8/9 is 50 MHz.
Table 16.4. PLL Lock Timing Characteristics
–40 to +85 °C unless otherwise specified
Input
Frequency
5 MHz
25 MHz
Multiplier
(Pll0mul)
20
13
16
9
12
6
10
5
4
2
3
2
2
1
2
1
Pll0flt
Setting
0x0F
0x0F
0x1F
0x1F
0x2F
0x2F
0x3F
0x3F
0x01
0x01
0x11
0x11
0x21
0x21
0x31
0x31
Output
Frequency
100 MHz
65 MHz
80 MHz
45 MHz
60 MHz
30 MHz
50 MHz
25 MHz
100 MHz
50 MHz
75 MHz
50 MHz
50 MHz
25 MHz
50 MHz
25 MHz
Rev. 1.2
Min
Typ
202
115
241
116
258
112
263
113
42
33
48
17
42
33
60
25
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
183
C8051F360/1/2/3/4/5/6/7/8/9
17. Port Input/Output
Digital and analog resources are available through up to 39 I/O pins. On the largest devices
(C8051F360/3), port pins are organized as four byte-wide Ports and one 7-bit-wide Port. On the other
devices (C8051F361/2/4/5/6/7/8/9), port pins are three byte-wide Ports and one partial port. Each of the
Port pins can be defined as general-purpose I/O (GPIO) or analog input/output; Port pins P0.0–P3.7 can
be assigned to one of the internal digital resources as shown in Figure 17.3. The designer has complete
control over which functions are assigned, limited only by the number of physical I/O pins. This resource
assignment flexibility is achieved through the use of a Priority Crossbar Decoder. Note that the state of a
Port I/O pin can always be read in the corresponding Port latch, regardless of the Crossbar settings.
The Crossbar assigns the selected internal digital resources to the I/O pins based on the peripheral priority
order of the Priority Decoder (Figure 17.3 and Figure 17.4). The registers XBR0 and XBR1, defined in SFR
Definition 17.1 and SFR Definition 17.2, are used to select internal digital functions.
All Port I/Os are 5 V tolerant (refer to Figure 17.2 for the Port cell circuit). The Port I/O cells are configured
as either push-pull or open-drain in the Port Output Mode registers (PnMDOUT, where n = 0,1,2,3,4). Complete Electrical Specifications for Port I/O are given in Table 17.1 on page 202.
P0MASK, P0MATCH
P1MASK, P1MATCH,
P2MASK, P2MATCH
Registers
XBR0, XBR1,
PnSKIP Registers
Priority
Decoder
Highest
Priority
UART
8
4
SPI
(Internal Digital Signals)
2
PnMDOUT,
PnMDIN Registers
SMBus
CP0
CP1
Outputs
2
Digital
Crossbar
8
P0.0
P1
I/O
Cells
P1.0
P2
I/O
Cell
P2.0
P3
I/O
Cells
P3.0
8
7
8
T0, T1
P0.7
P1.7
4
SYSCLK
PCA
Lowest
Priority
P0
I/O
Cells
2
8
P0
(P0.0-P0.7)
P1
(P1.0-P1.7)
P2
(P2.0-P2.7)
P2.7
3.1–3.4 available on
C8051F360/1/3/4/6/8
P3.7
3.5–3.7 available on
C8051F360/3
(Port Latches)
8
8
8
P3
(P3.0-P3.7)
Figure 17.1. Port I/O Functional Block Diagram (Port 0 through Port 3)
184
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
/WEAK-PULLUP
VDD
PUSH-PULL
/PORT-OUTENABLE
VDD
(WEAK)
PORT
PAD
PORT-OUTPUT
GND
Analog Select
ANALOG INPUT
PORT-INPUT
Figure 17.2. Port I/O Cell Block Diagram
Rev. 1.2
185
C8051F360/1/2/3/4/5/6/7/8/9
17.1. Priority Crossbar Decoder
The Priority Crossbar Decoder (Figure 17.3) assigns a priority to each I/O function, starting at the top with
UART0. When a digital resource is selected, the least-significant unassigned Port pin is assigned to that
resource (excluding UART0, which will be assigned to specific port pins (P0.1 and P0.2 in the
C8051F360/3 devices, P0.4 and P0.5 in the C8051F361/2/4/5/6/7/8/9 devices). If a Port pin is assigned,
the Crossbar skips that pin when assigning the next selected resource. Additionally, the Crossbar will skip
Port pins whose associated bits in the PnSKIP registers are set. The PnSKIP registers allow software to
skip Port pins that are to be used for analog input, dedicated functions, or GPIO.
Important Note on Crossbar Configuration: If a Port pin is claimed by a peripheral without use of the
Crossbar, its corresponding PnSKIP bit should be set. This applies to the port pins associated with the
external oscillator, VREF, external CNVSTR signal, IDA0, and any selected ADC or comparator inputs. The
Crossbar skips selected pins as if they were already assigned, and moves to the next unassigned pin.
Figure 17.3 shows the Crossbar Decoder priority with no Port pins skipped (P0SKIP, P1SKIP, P2SKIP,
P3SKIP = 0x00); Figure 17.4 shows the Crossbar Decoder priority with the P1.0 and P1.1 pins skipped
(P1SKIP = 0x03).
CNVSTR
XTAL1
XTAL2
CNVSTR
2
XTAL2
1
P3.5-P3.7
P3.1-P3.4
available
available on
on 48-pin
32/48-pin only
only
IDA0
0
P3
P2
P1
VREF
PIN I/O
IDA0
VREF
SF Signals
(48-pin)
XTAL1
SF Signals
(32- and 28pin)
ALE
P0
3
4
5
6
7
0
1
2
3
4
5
6
7
TX0
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
0
0
0
0
0
0
0
(32-pin and 28-pin packages)
RX0
TX0
(48-pin package)
RX0
SCK
MISO
MOSI
(*4-Wire SPI Only)
NSS*
SDA
SCL
CP0
CP0A
CP1
CP1A
/SYSCLK
CEX0
CEX1
CEX2
CEX3
CEX4
CEX5
ECI
T0
T1
0
0
0
0
0
0
P0SKIP[0:7]
0
0
0
0
0
0
0
0
0
0
P1SKIP[0:7]
0
0
0
0
0
0
P2SKIP[0:7]
0
0
P3SKIP[0:7]
Figure 17.3. Crossbar Priority Decoder with No Pins Skipped
186
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
P3
CNVSTR
XTAL1
XTAL2
CNVSTR
2
XTAL2
1
P2
P3.5-P3.7
P3.1-P3.4
available
available on
on 48-pin
32/48-pin only
only
IDA0
0
P1
VREF
PIN I/O
IDA0
VREF
SF Signals
(48-pin)
XTAL1
SF Signals
(32- and 28pin)
ALE
P0
3
4
5
6
7
0
1
2
3
4
5
6
7
TX0
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
0
0
0
0
0
0
0
(32-pin and 28-pin packages)
RX0
TX0
(48-pin package)
RX0
SCK
MISO
MOSI
(*4-Wire SPI Only)
NSS*
SDA
SCL
CP0
CP0A
CP1
CP1A
/SYSCLK
CEX0
CEX1
CEX2
CEX3
CEX4
CEX5
ECI
T0
T1
0
0
0
0
0
0
P0SKIP[0:7]
0
0
1
1
0
0
0
0
0
0
0
P1SKIP[0:7]
0
0
0
0
0
P2SKIP[0:7]
0
0
P3SKIP[0:7]
Figure 17.4. Crossbar Priority Decoder with Port Pins Skipped
Registers XBR0 and XBR1 are used to assign the digital I/O resources to the physical I/O Port pins. Note
that when the SMBus is selected, the Crossbar assigns both pins associated with the SMBus (SDA and
SCL); when the UART is selected, the Crossbar assigns both pins associated with the UART (TX and RX).
UART0 pin assignments are fixed for bootloading purposes: UART TX0 is always assigned to P0.1
(C8051F360/3) or P0.4 (C8051F361/2/4/5/6/7/8/9); UART RX0 is always assigned to P0.2 (C8051F360/3)
or P0.5 (C8051F361/2/4/5/6/7/8/9). Standard Port I/Os appear contiguously starting at P0.0 after prioritized
functions and skipped pins are assigned.
Important Note: The SPI can be operated in either 3-wire or 4-wire modes, depending on the state of the
NSSMD1-NSSMD0 bits in register SPI0CN. According to the SPI mode, the NSS signal may or may not be
routed to a Port pin.
Rev. 1.2
187
C8051F360/1/2/3/4/5/6/7/8/9
17.2. Port I/O Initialization
Port I/O initialization consists of the following steps:
Step 1. Select the input mode (analog or digital) for all Port pins, using the Port Input Mode
register (PnMDIN).
Step 2. Select the output mode (open-drain or push-pull) for all Port pins, using the Port Output
Mode register (PnMDOUT).
Step 3. Select any pins to be skipped by the I/O Crossbar using the Port Skip registers (PnSKIP).
Step 4. Assign Port pins to desired peripherals using the XBRn registers.
Step 5. Enable the Crossbar (XBARE = ‘1’).
All Port pins must be configured as either analog or digital inputs. Any pins to be used as Comparator or
ADC inputs should be configured as an analog inputs. When a pin is configured as an analog input, its
weak pullup, digital driver, and digital receiver are disabled. This process saves power and reduces noise
on the analog input. Pins configured as digital inputs may still be used by analog peripherals; however, this
practice is not recommended.
Additionally, all analog input pins should be configured to be skipped by the Crossbar (accomplished by
setting the associated bits in PnSKIP). Port input mode is set in the PnMDIN register, where a ‘1’ indicates
a digital input, and a ‘0’ indicates an analog input. All pins default to digital inputs on reset. See SFR Definition 17.4 for the PnMDIN register details.
The output driver characteristics of the I/O pins are defined using the Port Output Mode registers (PnMDOUT). Each Port Output driver can be configured as either open drain or push-pull. This selection is
required even for the digital resources selected in the XBRn registers, and is not automatic. The only
exception to this is the SMBus (SDA, SCL) pins, which are configured as open-drain regardless of the
PnMDOUT settings. When the WEAKPUD bit in XBR1 is ‘0’, a weak pullup is enabled for all Port I/O configured as open-drain. WEAKPUD does not affect the push-pull Port I/O. Furthermore, the weak pullup is
turned off on an output that is driving a ‘0’ and for pins configured for analog input mode to avoid unnecessary power dissipation.
Registers XBR0 and XBR1 must be loaded with the appropriate values to select the digital I/O functions
required by the design. Setting the XBARE bit in XBR1 to ‘1’ enables the Crossbar. Until the Crossbar is
enabled, the external pins remain as standard Port I/O (in input mode), regardless of the XBRn Register
settings. For given XBRn Register settings, one can determine the I/O pin-out using the Priority Decode
Table; as an alternative, the Configuration Wizard utility of the Silicon Labs IDE software will determine the
Port I/O pin-assignments based on the XBRn Register settings.
The Crossbar must be enabled to use Port pins as standard Port I/O in output mode. Port output drivers
are disabled while the Crossbar is disabled.
188
Rev. 1.2
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SFR Definition 17.1. XBR0: Port I/O Crossbar Register 0
SFR Page:
F
SFR Address: 0xE1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
CP1AE
CP1E
CP0AE
CP0E
SYSCKE
SMB0E
SPI0E
URT0E
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
CP1AE: Comparator1 Asynchronous Output Enable
0: Asynchronous CP1 unavailable at Port pin.
1: Asynchronous CP1 routed to Port pin.
CP1E: Comparator1 Output Enable
0: CP1 unavailable at Port pin.
1: CP1 routed to Port pin.
CP0AE: Comparator0 Asynchronous Output Enable
0: Asynchronous CP0 unavailable at Port pin.
1: Asynchronous CP0 routed to Port pin.
CP0E: Comparator0 Output Enable
0: CP0 unavailable at Port pin.
1: CP0 routed to Port pin.
SYSCKE: /SYSCLK Output Enable
0: /SYSCLK unavailable at Port pin.
1: /SYSCLK (divided by 1, 2, 4, or 8) routed to Port pin. The divide factor is determined by
the CLKDIV1–0 bits in register CLKSEL (See Section Section “16. Oscillators” on
page 170).
SMB0E: SMBus I/O Enable
0: SMBus I/O unavailable at Port pins.
1: SMBus I/O routed to Port pins.
SPI0E: SPI I/O Enable
0: SPI I/O unavailable at Port pins.
1: SPI I/O routed to Port pins. Note that the SPI can be assigned either 3 or 4 GPIO pins.
URT0E: UART I/O Output Enable
0: UART I/O unavailable at Port pin.
1: UART TX0, RX0 routed to Port pins P0.1 and P0.2 (C8051F360/3) or P0.4 and P0.5
(C8051F361/2/4/5/6/7/8/9).
Rev. 1.2
189
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.2. XBR1: Port I/O Crossbar Register 1
SFR Page:
SFR Address:
R/W
F
0xE2
R/W
WEAKPUD XBARE
Bit7
Bit6
R/W
R/W
R/W
T1E
T0E
ECIE
Bit5
Bit4
Bit3
Bit 7:
R/W
R/W
R/W
PCA0ME
Bit2
Bit1
Reset Value
00000000
Bit0
WEAKPUD: Port I/O Weak Pullup Disable.
0: Weak Pullups enabled (except for Ports whose I/O are configured as analog input).
1: Weak Pullups disabled.
Bit 6:
XBARE: Crossbar Enable.
0: Crossbar disabled.
1: Crossbar enabled.
Bit 5:
T1E: T1 Enable
0: T1 unavailable at Port pin.
1: T1 routed to Port pin.
Bit 4:
T0E: T0 Enable
0: T0 unavailable at Port pin.
1: T0 routed to Port pin.
Bit 3:
ECIE: PCA0 External Counter Input Enable
0: ECI unavailable at Port pin.
1: ECI routed to Port pin.
Bits 2–0: PCA0ME: PCA Module I/O Enable Bits.
000: All PCA I/O unavailable at Port pins.
001: CEX0 routed to Port pin.
010: CEX0, CEX1 routed to Port pins.
011: CEX0, CEX1, CEX2 routed to Port pins.
100: CEX0, CEX1, CEX2, CEX3 routed to Port pins.
101: CEX0, CEX1, CEX2, CEX3, CEX4 routed to Port pins.
110: CEX0, CEX1, CEX2, CEX3, CEX4, CEX5 routed to Port pins.
111: Reserved.
190
Rev. 1.2
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17.3. General Purpose Port I/O
Port pins that remain unassigned by the Crossbar and are not used by analog peripherals can be used for
general purpose I/O. Ports P0-P3 are accessed through corresponding special function registers (SFRs)
that are both byte-addressable and bit-addressable. Port 4 (C8051F360/3 only) uses an SFR which is
byte-addressable. When writing to a Port, the value written to the SFR is latched to maintain the output
data value at each pin. When reading, the logic levels of the Port's input pins are returned regardless of the
XBRn settings (i.e., even when the pin is assigned to another signal by the Crossbar, the Port register can
always read its corresponding Port I/O pin). The exception to this is the execution of the read-modify-write
instructions that target a Port Latch register as the destination. The read-modify-write instructions when
operating on a Port SFR are the following: ANL, ORL, XRL, JBC, CPL, INC, DEC, DJNZ and MOV, CLR or
SETB, when the destination is an individual bit in a Port SFR. For these instructions, the value of the latch
register (not the pin) is read, modified, and written back to the SFR.
In addition to performing general purpose I/O, P0, P1, and P2 can generate a port match event if the logic
levels of the Port’s input pins match a software controlled value. A port match event is generated if
(P0 & P0MASK) does not equal (P0MATCH & P0MASK), if (P1 & P1MASK) does not equal
(P1MATCH & P1MASK), or if (P2 & P2MASK) does not equal (P2MATCH & P2MASK). This allows Software to be notified if a certain change or pattern occurs on P0, P1, or P2 input pins regardless of the XBRn
settings. A port match event can cause an interrupt if EMAT (EIE2.1) is set to '1' or cause the internal oscillator to awaken from SUSPEND mode. See Section “16.1.1. Internal Oscillator Suspend Mode” on
page 171 for more information.
SFR Definition 17.3. P0: Port0
SFR Page:
all pages
SFR Address: 0x80
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P0.7
P0.6
P0.5
P0.4
P0.3
P0.2
P0.1
P0.0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P0.[7:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P0MDOUT.n bit = 0).
Read - Always reads ‘0’ if selected as analog input in register P0MDIN. Directly reads Port
pin when configured as digital input.
0: P0.n pin is logic low.
1: P0.n pin is logic high.
Rev. 1.2
191
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.4. P0MDIN: Port0 Input Mode
SFR Page:
F
SFR Address: 0xF1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Analog Input Configuration Bits for P0.7-P0.0 (respectively).
Port pins configured as analog inputs have their weak pullup, digital driver, and digital
receiver disabled.
0: Corresponding P0.n pin is configured as an analog input.
1: Corresponding P0.n pin is not configured as an analog input.
SFR Definition 17.5. P0MDOUT: Port0 Output Mode
SFR Page:
F
SFR Address: 0xA4
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Output Configuration Bits for P0.7-P0.0 (respectively): ignored if corresponding bit in register P0MDIN is logic ‘0’.
0: Corresponding P0.n Output is open-drain.
1: Corresponding P0.n Output is push-pull.
Note:
192
When SDA and SCL appear on any of the Port I/O, each are open-drain regardless of the value of
P0MDOUT.
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.6. P0SKIP: Port0 Skip
SFR Page:
F
SFR Address: 0xD4
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: P0SKIP[7:0]: Port0 Crossbar Skip Enable Bits.
These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar.
0: Corresponding P0.n pin is not skipped by the Crossbar.
1: Corresponding P0.n pin is skipped by the Crossbar.
SFR Definition 17.7. P0MAT: Port0 Match
SFR Page:
0
SFR Address: 0xF3
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: P0MAT[7:0]: Port0 Match Value.
These bits control the value that unmasked P0 Port pins are compared against. A Port
Match event is generated if (P0 & P0MASK) does not equal (P0MAT & P0MASK).
SFR Definition 17.8. P0MASK: Port0 Mask
SFR Page:
0
SFR Address: 0xF4
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P0MASK[7:0]: Port0 Mask Value.
These bits select which Port pins will be compared to the value stored in P0MAT.
0: Corresponding P0.n pin is ignored and cannot cause a Port Match event.
1: Corresponding P0.n pin is compared to the corresponding bit in P0MAT.
Rev. 1.2
193
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.9. P1: Port1
SFR Page:
all pages
SFR Address: 0x90
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P1.7
P1.6
P1.5
P1.4
P1.3
P1.2
P1.1
P1.0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P1.[7:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P1MDOUT.n bit = 0).
Read - Always reads ‘0’ if selected as analog input in register P1MDIN. Directly reads Port
pin when configured as digital input.
0: P1.n pin is logic low.
1: P1.n pin is logic high.
SFR Definition 17.10. P1MDIN: Port1 Input Mode
SFR Page:
F
SFR Address: 0xF2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: Analog Input Configuration Bits for P1.7-P1.0 (respectively).
Port pins configured as analog inputs have their weak pullup, digital driver, and digital
receiver disabled.
0: Corresponding P1.n pin is configured as an analog input.
1: Corresponding P1.n pin is not configured as an analog input.
194
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.11. P1MDOUT: Port1 Output Mode
SFR Page:
F
SFR Address: 0xA5
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Output Configuration Bits for P1.7-P1.0 (respectively): ignored if corresponding bit in register P1MDIN is logic ‘0’.
0: Corresponding P1.n Output is open-drain.
1: Corresponding P1.n Output is push-pull.
SFR Definition 17.12. P1SKIP: Port1 Skip
SFR Page:
F
SFR Address: 0xD5
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: P1SKIP[7:0]: Port1 Crossbar Skip Enable Bits.
These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar.
0: Corresponding P1.n pin is not skipped by the Crossbar.
1: Corresponding P1.n pin is skipped by the Crossbar.
SFR Definition 17.13. P1MAT: Port1 Match
SFR Page:
0
SFR Address: 0xE1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: P1MAT[7:0]: Port1 Match Value.
These bits control the value that unmasked P0 Port pins are compared against. A Port
Match event is generated if (P1 & P1MASK) does not equal (P1MAT & P1MASK).
Rev. 1.2
195
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.14. P1MASK: Port1 Mask
SFR Page:
0
SFR Address: 0xE2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P1MASK[7:0]: Port1 Mask Value.
These bits select which Port pins will be compared to the value stored in P1MAT.
0: Corresponding P1.n pin is ignored and cannot cause a Port Match event.
1: Corresponding P1.n pin is compared to the corresponding bit in P1MAT.
SFR Definition 17.15. P2: Port2
SFR Page:
all pages
SFR Address: 0xA0
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P2.7
P2.6
P2.5
P2.4
P2.3
P2.2
P2.1
P2.0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P2.[7:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P2MDOUT.n bit = 0).
Read - Always reads ‘0’ if selected as analog input in register P2MDIN. Directly reads Port
pin when configured as digital input.
0: P2.n pin is logic low.
1: P2.n pin is logic high.
196
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.16. P2MDIN: Port2 Input Mode
SFR Page:
F
SFR Address: 0xF3
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: Analog Input Configuration Bits for P2.7-P2.0 (respectively).
Port pins configured as analog inputs have their weak pullup, digital driver, and digital
receiver disabled.
0: Corresponding P2.n pin is configured as an analog input.
1: Corresponding P2.n pin is not configured as an analog input.
SFR Definition 17.17. P2MDOUT: Port2 Output Mode
SFR Page:
F
SFR Address: 0xA6
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: Output Configuration Bits for P2.7-P2.0 (respectively): ignored if corresponding bit in register P2MDIN is logic ‘0’.
0: Corresponding P2.n Output is open-drain.
1: Corresponding P2.n Output is push-pull.
Rev. 1.2
197
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.18. P2SKIP: Port2 Skip
SFR Page:
F
SFR Address: 0xD6
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P2SKIP[7:0]: Port2 Crossbar Skip Enable Bits.
These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar.
0: Corresponding P2.n pin is not skipped by the Crossbar.
1: Corresponding P2.n pin is skipped by the Crossbar.
SFR Definition 17.19. P2MAT: Port2 Match
SFR Page:
0
SFR Address: 0xB1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: P2MAT[7:0]: Port2 Match Value.
These bits control the value that unmasked P2 Port pins are compared against. A Port
Match event is generated if (P2 & P2MASK) does not equal (P2MAT & P2MASK).
SFR Definition 17.20. P2MASK: Port2 Mask
SFR Page:
0
SFR Address: 0xB2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P2MASK[7:0]: Port2 Mask Value.
These bits select which Port pins will be compared to the value stored in P2MAT.
0: Corresponding P2.n pin is ignored and cannot cause a Port Match event.
1: Corresponding P2.n pin is compared to the corresponding bit in P2MAT.
198
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.21. P3: Port3
SFR Page:
all pages
SFR Address: 0xB0
(bit addressable)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P3.7
P3.6
P3.5
P3.4
P3.3
P3.2
P3.1
P3.0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: P3.[7:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P3MDOUT.n bit = 0).
Read - Always reads ‘0’ if selected as analog input in register P3MDIN. Directly reads Port
pin when configured as digital input.
0: P3.n pin is logic low.
1: P3.n pin is logic high.
SFR Definition 17.22. P3MDIN: Port3 Input Mode
SFR Page:
F
SFR Address: 0xF4
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
Bits 7–0: Analog Input Configuration Bits for P3.7-P3.0 (respectively).
Port pins configured as analog inputs have their weak pullup, digital driver, and digital
receiver disabled.
0: Corresponding P3.n pin is configured as an analog input.
1: Corresponding P3.n pin is not configured as an analog input.
Rev. 1.2
199
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.23. P3MDOUT: Port3 Output Mode
SFR Page:
F
SFR Address: 0xAF
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: Output Configuration Bits for P3.7-P3.0 (respectively): ignored if corresponding bit in register P3MDIN is logic ‘0’.
0: Corresponding P3.n Output is open-drain.
1: Corresponding P3.n Output is push-pull.
SFR Definition 17.24. P3SKIP: Port3 Skip
SFR Page:
F
SFR Address: 0xD7
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: P3SKIP[7:0]: Port3 Crossbar Skip Enable Bits.
These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar.
0: Corresponding P3.n pin is not skipped by the Crossbar.
1: Corresponding P3.n pin is skipped by the Crossbar.
200
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 17.25. P4: Port4
SFR Page:
all pages
SFR Address: 0xB5
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
–
P4.6
P4.5
P4.4
P4.3
P4.2
P4.1
P4.0
01111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
UNUSED. Read = 0b. Write = don’t care.
Bits 6–0: P4.[6:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P4MDOUT.n bit = 0).
Read - Directly reads Port pin.
0: P4.n pin is logic low.
1: P4.n pin is logic high.
SFR Definition 17.26. P4MDOUT: Port4 Output Mode
SFR Page:
F
SFR Address: 0xAE
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
–
Bit7
Reset Value
00000000
Bit 7:
UNUSED. Read = 0b. Write = don’t care.
Bits 6–0: Output Configuration Bits for P4.6-P4.0 (respectively).
0: Corresponding P4.n Output is open-drain.
1: Corresponding P4.n Output is push-pull.
Rev. 1.2
201
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Table 17.1. Port I/O DC Electrical Characteristics
VDD = 2.7 to 3.6 V, –40 to +85 °C unless otherwise specified.
Parameters
Conditions
IOH = –3 mA, Port I/O push-pull
Min
VDD – 0.7
Typ
—
Max
VDD – 0.1
—
—
IOH = –10 mA, Port I/O push-pull
—
VDD – 0.8
—
IOL = 8.5 mA
—
—
0.6
IOL = 10 µA
—
—
0.1
IOL = 25 mA
—
1.0
—
Weak Pullup Off
2.0
—
—
—
—
—
—
0.8
±1
Weak Pullup On, VIN = 0 V
—
25
50
Output High Voltage IOH = –10 µA, Port I/O push-pull
Output Low Voltage
Input High Voltage
Input Low Voltage
Input Leakage
Current
202
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Units
—
V
V
V
V
µA
C8051F360/1/2/3/4/5/6/7/8/9
18. SMBus
The SMBus I/O interface is a two-wire, bi-directional serial bus. The SMBus is compliant with the System
Management Bus Specification, version 1.1, and compatible with the I2C serial bus. Reads and writes to
the interface by the system controller are byte oriented with the SMBus interface autonomously controlling
the serial transfer of the data. Data can be transferred at up to 1/10th of the system clock as a master or
slave (this can be faster than allowed by the SMBus specification, depending on the system clock used). A
method of extending the clock-low duration is available to accommodate devices with different speed
capabilities on the same bus.
The SMBus interface may operate as a master and/or slave, and may function on a bus with multiple masters. The SMBus provides control of SDA (serial data), SCL (serial clock) generation and synchronization,
arbitration logic, and START/STOP control and generation. Three SFRs are associated with the SMBus:
SMB0CF configures the SMBus; SMB0CN controls the status of the SMBus; and SMB0DAT is the data
register, used for both transmitting and receiving SMBus data and slave addresses.
SMB0CN
MT S S A A A S
A X T T CRC I
SMAOK B K
T O
R L
E D
QO
R E
S
T
SMB0CF
E I B E S S S S
N N U XMMMM
S H S T B B B B
M Y H T F CC
B
OOT S S
L E E 1 0
D
00
T0 Overflow
01
T1 Overflow
10
TMR2H Overflow
11
TMR2L Overflow
SMBUS CONTROL LOGIC
Interrupt
Request
Arbitration
SCL Synchronization
SCL Generation (Master Mode)
SDA Control
Data Path
IRQ Generation
Control
SCL
FILTER
SCL
Control
C
R
O
S
S
B
A
R
N
SDA
Control
SMB0DAT
7 6 5 4 3 2 1 0
Port I/O
SDA
FILTER
N
Figure 18.1. SMBus Block Diagram
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18.1. Supporting Documents
It is assumed the reader is familiar with or has access to the following supporting documents:
1. The I2C-Bus and How to Use It (including specifications), Philips Semiconductor.
2. The I2C-Bus Specification—Version 2.0, Philips Semiconductor.
3. System Management Bus Specification—Version 1.1, SBS Implementers Forum.
18.2. SMBus Configuration
Figure 18.2 shows a typical SMBus configuration. The SMBus specification allows any recessive voltage
between 3.0 V and 5.0 V; different devices on the bus may operate at different voltage levels. The bi-directional SCL (serial clock) and SDA (serial data) lines must be connected to a positive power supply voltage
through a pullup resistor or similar circuit. Every device connected to the bus must have an open-drain or
open-collector output for both the SCL and SDA lines, so that both are pulled high (recessive state) when
the bus is free. The maximum number of devices on the bus is limited only by the requirement that the rise
and fall times on the bus not exceed 300 ns and 1000 ns, respectively.
VDD = 5 V
VDD = 3 V
VDD = 5 V
VDD = 3 V
Master
Device
Slave
Device 1
Slave
Device 2
SDA
SCL
Figure 18.2. Typical SMBus Configuration
18.3. SMBus Operation
Two types of data transfers are possible: data transfers from a master transmitter to an addressed slave
receiver (WRITE), and data transfers from an addressed slave transmitter to a master receiver (READ).
The master device initiates both types of data transfers and provides the serial clock pulses on SCL. The
SMBus interface may operate as a master or a slave, and multiple master devices on the same bus are
supported. If two or more masters attempt to initiate a data transfer simultaneously, an arbitration scheme
is employed with a single master always winning the arbitration. Note that it is not necessary to specify one
device as the Master in a system; any device who transmits a START and a slave address becomes the
master for the duration of that transfer.
A typical SMBus transaction consists of a START condition followed by an address byte (Bits7–1: 7-bit
slave address; Bit0: R/W direction bit), one or more bytes of data, and a STOP condition. Each byte that is
received (by a master or slave) must be acknowledged (ACK) with a low SDA during a high SCL (see
Figure 18.3). If the receiving device does not ACK, the transmitting device will read a NACK (not acknowledge), which is a high SDA during a high SCL.
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The direction bit (R/W) occupies the least-significant bit position of the address byte. The direction bit is set
to logic ‘1’ to indicate a "READ" operation and cleared to logic ‘0’ to indicate a "WRITE" operation.
All transactions are initiated by a master, with one or more addressed slave devices as the target. The
master generates the START condition and then transmits the slave address and direction bit. If the transaction is a WRITE operation from the master to the slave, the master transmits the data a byte at a time
waiting for an ACK from the slave at the end of each byte. For READ operations, the slave transmits the
data waiting for an ACK from the master at the end of each byte. At the end of the data transfer, the master
generates a STOP condition to terminate the transaction and free the bus. Figure 18.3 illustrates a typical
SMBus transaction.
SCL
SDA
SLA6
START
SLA5-0
Slave Address + R/W
R/W
D7
ACK
D6-0
Data Byte
NACK
STOP
Figure 18.3. SMBus Transaction
18.3.1. Arbitration
A master may start a transfer only if the bus is free. The bus is free after a STOP condition or after the SCL
and SDA lines remain high for a specified time (see Section “18.3.4. SCL High (SMBus Free) Timeout” on
page 206). In the event that two or more devices attempt to begin a transfer at the same time, an arbitration scheme is employed to force one master to give up the bus. The master devices continue transmitting
until one attempts a HIGH while the other transmits a LOW. Since the bus is open-drain, the bus will be
pulled LOW. The master attempting the HIGH will detect a LOW SDA and lose the arbitration. The winning
master continues its transmission without interruption; the losing master becomes a slave and receives the
rest of the transfer if addressed. This arbitration scheme is non-destructive: one device always wins, and
no data is lost.
18.3.2. Clock Low Extension
SMBus provides a clock synchronization mechanism, similar to I2C, which allows devices with different
speed capabilities to coexist on the bus. A clock-low extension is used during a transfer in order to allow
slower slave devices to communicate with faster masters. The slave may temporarily hold the SCL line
LOW to extend the clock low period, effectively decreasing the serial clock frequency.
18.3.3. SCL Low Timeout
If the SCL line is held low by a slave device on the bus, no further communication is possible. Furthermore,
the master cannot force the SCL line high to correct the error condition. To solve this problem, the SMBus
protocol specifies that devices participating in a transfer must detect any clock cycle held low longer than
25 ms as a “timeout” condition. Devices that have detected the timeout condition must reset the communication no later than 10 ms after detecting the timeout condition.
When the SMBTOE bit in SMB0CF is set, Timer 3 is used to detect SCL low timeouts. Timer 3 is forced to
reload when SCL is high, and allowed to count when SCL is low. With Timer 3 enabled and configured to
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overflow after 25 ms (and SMBTOE set), the Timer 3 interrupt service routine can be used to reset (disable
and re-enable) the SMBus in the event of an SCL low timeout.
18.3.4. SCL High (SMBus Free) Timeout
The SMBus specification stipulates that if the SCL and SDA lines remain high for more that 50 µs, the bus
is designated as free. When the SMBFTE bit in SMB0CF is set, the bus will be considered free if SCL and
SDA remain high for more than 10 SMBus clock source periods. If the SMBus is waiting to generate a
Master START, the START will be generated following this timeout. Note that a clock source is required for
free timeout detection, even in a slave-only implementation.
18.4. Using the SMBus
The SMBus can operate in both Master and Slave modes. The interface provides timing and shifting control for serial transfers; higher level protocol is determined by user software. The SMBus interface provides
the following application-independent features:
•
•
•
•
•
•
•
Byte-wise serial data transfers
Clock signal generation on SCL (Master Mode only) and SDA data synchronization
Timeout/bus error recognition, as defined by the SMB0CF configuration register
START/STOP timing, detection, and generation
Bus arbitration
Interrupt generation
Status information
SMBus interrupts are generated for each data byte or slave address that is transferred. When transmitting,
this interrupt is generated after the ACK cycle so that software may read the received ACK value; when
receiving data, this interrupt is generated before the ACK cycle so that software may define the outgoing
ACK value. See Section “18.5. SMBus Transfer Modes” on page 214 for more details on transmission
sequences.
Interrupts are also generated to indicate the beginning of a transfer when a master (START generated), or
the end of a transfer when a slave (STOP detected). Software should read the SMB0CN (SMBus Control
register) to find the cause of the SMBus interrupt. The SMB0CN register is described in Section
“18.4.2. SMB0CN Control Register” on page 210; Table 18.4 provides a quick SMB0CN decoding reference.
SMBus configuration options include:
•
•
•
•
Timeout detection (SCL Low Timeout and/or Bus Free Timeout)
SDA setup and hold time extensions
Slave event enable/disable
Clock source selection
These options are selected in the SMB0CF register, as described in Section “18.4.1. SMBus Configuration
Register” on page 207.
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18.4.1. SMBus Configuration Register
The SMBus Configuration register (SMB0CF) is used to enable the SMBus Master and/or Slave modes,
select the SMBus clock source, and select the SMBus timing and timeout options. When the ENSMB bit is
set, the SMBus is enabled for all master and slave events. Slave events may be disabled by setting the
INH bit. With slave events inhibited, the SMBus interface will still monitor the SCL and SDA pins; however,
the interface will NACK all received addresses and will not generate any slave interrupts. When the INH bit
is set, all slave events will be inhibited following the next START (interrupts will continue for the duration of
the current transfer).
Table 18.1. SMBus Clock Source Selection
SMBCS1
0
0
1
1
SMBCS0
0
1
0
1
SMBus Clock Source
Timer 0 Overflow
Timer 1 Overflow
Timer 2 High Byte Overflow
Timer 2 Low Byte Overflow
The SMBCS1–0 bits select the SMBus clock source, which is used only when operating as a master or
when the Free Timeout detection is enabled. When operating as a master, overflows from the selected
source determine the absolute minimum SCL low and high times as defined in Equation 18.1. Note that the
selected clock source may be shared by other peripherals so long as the timer is left running at all times.
For example, Timer 1 overflows may generate the SMBus and UART baud rates simultaneously. Timer
configuration is covered in Section “21. Timers” on page 248.
1
T HighMin = T LowMin = ---------------------------------------------f ClockSourceOverflow
Equation 18.1. Minimum SCL High and Low Times
The selected clock source should be configured to establish the minimum SCL High and Low times as per
Equation 18.1. When the interface is operating as a master (and SCL is not driven or extended by any
other devices on the bus), the typical SMBus bit rate is approximated by Equation 18.2.
f ClockSourceOverflow
BitRate = ---------------------------------------------3
Equation 18.2. Typical SMBus Bit Rate
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Figure 18.4 shows the typical SCL generation described by Equation 18.2. Notice that THIGH is typically
twice as large as TLOW. The actual SCL output may vary due to other devices on the bus (SCL may be
extended low by slower slave devices, or driven low by contending master devices). The bit rate when
operating as a master will never exceed the limits defined by equation Equation 18.1.
Timer Source
Overflows
SCL
TLow
SCL High Timeout
THigh
Figure 18.4. Typical SMBus SCL Generation
Setting the EXTHOLD bit extends the minimum setup and hold times for the SDA line. The minimum SDA
setup time defines the absolute minimum time that SDA is stable before SCL transitions from low-to-high.
The minimum SDA hold time defines the absolute minimum time that the current SDA value remains stable
after SCL transitions from high-to-low. EXTHOLD should be set so that the minimum setup and hold times
meet the SMBus Specification requirements of 250 ns and 300 ns, respectively. Table 18.2 shows the minimum setup and hold times for the two EXTHOLD settings. Setup and hold time extensions are typically
necessary when SYSCLK is above 10 MHz.
Table 18.2. Minimum SDA Setup and Hold Times
EXTHOLD
Minimum SDA Setup Time
Tlow – 4 system clocks
Minimum SDA Hold Time
0
or
3 system clocks
1
1 system clock + s/w delay*
11 system clocks
12 system clocks
*Note: Setup Time for ACK bit transmissions and the MSB of all data transfers. The s/w
delay occurs between the time SMB0DAT or ACK is written and when SI is cleared.
Note that if SI is cleared in the same write that defines the outgoing ACK value, s/w
delay is zero.
With the SMBTOE bit set, Timer 3 should be configured to overflow after 25 ms in order to detect SCL low
timeouts (see Section “18.3.3. SCL Low Timeout” on page 205). The SMBus interface will force Timer 3 to
reload while SCL is high, and allow Timer 3 to count when SCL is low. The Timer 3 interrupt service routine
should be used to reset SMBus communication by disabling and re-enabling the SMBus.
SMBus Free Timeout detection can be enabled by setting the SMBFTE bit. When this bit is set, the bus will
be considered free if SDA and SCL remain high for more than 10 SMBus clock source periods (see
Figure 18.4). When a Free Timeout is detected, the interface will respond as if a STOP was detected (an
interrupt will be generated, and STO will be set).
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SFR Definition 18.1. SMB0CF: SMBus Clock/Configuration
SFR Page:
all pages
SFR Address: 0xC1
R/W
R/W
R
ENSMB
INH
BUSY
Bit7
Bit6
Bit5
R/W
R/W
R/W
R/W
EXTHOLD SMBTOE SMBFTE SMBCS1
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
SMBCS0
00000000
Bit0
Bit 7:
ENSMB: SMBus Enable.
This bit enables/disables the SMBus interface. When enabled, the interface constantly monitors the SDA and SCL pins.
0: SMBus interface disabled.
1: SMBus interface enabled.
Bit 6:
INH: SMBus Slave Inhibit.
When this bit is set to logic ‘1’, the SMBus does not generate an interrupt when slave events
occur. This effectively removes the SMBus slave from the bus. Master Mode interrupts are
not affected.
0: SMBus Slave Mode enabled.
1: SMBus Slave Mode inhibited.
Bit 5:
BUSY: SMBus Busy Indicator.
This bit is set to logic ‘1’ by hardware when a transfer is in progress. It is cleared to logic ‘0’
when a STOP or free-timeout is sensed.
Bit 4:
EXTHOLD: SMBus Setup and Hold Time Extension Enable.
This bit controls the SDA setup and hold times according to:
0: SDA Extended Setup and Hold Times disabled.
1: SDA Extended Setup and Hold Times enabled.
Bit 3:
SMBTOE: SMBus SCL Timeout Detection Enable.
This bit enables SCL low timeout detection. If set to logic ‘1’, the SMBus forces Timer 3 to
reload while SCL is high and allows Timer 3 to count when SCL goes low. If Timer 3 is configured to Split Mode, only the High Byte of the timer is held in reload while SCL is high.
Timer 3 should be programmed to generate interrupts at 25 ms, and the Timer 3 interrupt
service routine should reset SMBus communication.
Bit 2:
SMBFTE: SMBus Free Timeout Detection Enable.
When this bit is set to logic ‘1’, the bus will be considered free if SCL and SDA remain high
for more than 10 SMBus clock source periods.
Bits 1–0: SMBCS1–SMBCS0: SMBus Clock Source Selection.
These two bits select the SMBus clock source, which is used to generate the SMBus bit
rate. The selected device should be configured according to Equation 18.1.
SMBCS1
0
0
1
1
SMBCS0
0
1
0
1
SMBus Clock Source
Timer 0 Overflow
Timer 1 Overflow
Timer 2 High Byte Overflow
Timer 2 Low Byte Overflow
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18.4.2. SMB0CN Control Register
SMB0CN is used to control the interface and to provide status information (see SFR Definition 18.2). The
higher four bits of SMB0CN (MASTER, TXMODE, STA, and STO) form a status vector that can be used to
jump to service routines. MASTER and TXMODE indicate the master/slave state and transmit/receive
modes, respectively.
STA and STO indicate that a START and/or STOP has been detected or generated since the last SMBus
interrupt. STA and STO are also used to generate START and STOP conditions when operating as a master. Writing a ‘1’ to STA will cause the SMBus interface to enter Master Mode and generate a START when
the bus becomes free (STA is not cleared by hardware after the START is generated). Writing a ‘1’ to STO
while in Master Mode will cause the interface to generate a STOP and end the current transfer after the
next ACK cycle. If STO and STA are both set (while in Master Mode), a STOP followed by a START will be
generated.
As a receiver, writing the ACK bit defines the outgoing ACK value; as a transmitter, reading the ACK bit
indicates the value received on the last ACK cycle. ACKRQ is set each time a byte is received, indicating
that an outgoing ACK value is needed. When ACKRQ is set, software should write the desired outgoing
value to the ACK bit before clearing SI. A NACK will be generated if software does not write the ACK bit
before clearing SI. SDA will reflect the defined ACK value immediately following a write to the ACK bit;
however SCL will remain low until SI is cleared. If a received slave address is not acknowledged, further
slave events will be ignored until the next START is detected.
The ARBLOST bit indicates that the interface has lost an arbitration. This may occur anytime the interface
is transmitting (master or slave). A lost arbitration while operating as a slave indicates a bus error condition. ARBLOST is cleared by hardware each time SI is cleared.
The SI bit (SMBus Interrupt Flag) is set at the beginning and end of each transfer, after each byte frame, or
when an arbitration is lost; see Table 18.3 for more details.
Important Note About the SI Bit: The SMBus interface is stalled while SI is set; thus SCL is held low, and
the bus is stalled until software clears SI.
Table 18.3 lists all sources for hardware changes to the SMB0CN bits. Refer to Table 18.4 for SMBus status decoding using the SMB0CN register.
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SFR Definition 18.2. SMB0CN: SMBus Control
SFR Page:
all pages
SFR Address: 0xC0
R
R
MASTER TXMODE
Bit7
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
Bit6
(bit addressable)
R/W
R/W
STA
STO
Bit5
Bit4
R
R
ACKRQ ARBLOST
Bit3
Bit2
R/W
R/W
Reset Value
ACK
SI
00000000
Bit1
Bit0
MASTER: SMBus Master/Slave Indicator.
This read-only bit indicates when the SMBus is operating as a master.
0: SMBus operating in Slave Mode.
1: SMBus operating in Master Mode.
TXMODE: SMBus Transmit Mode Indicator.
This read-only bit indicates when the SMBus is operating as a transmitter.
0: SMBus in Receiver Mode.
1: SMBus in Transmitter Mode.
STA: SMBus Start Flag.
Write:
0: No Start generated.
1: When operating as a master, a START condition is transmitted if the bus is free (If the bus
is not free, the START is transmitted after a STOP is received or a timeout is detected). If
STA is set by software as an active Master, a repeated START will be generated after the
next ACK cycle.
Read:
0: No Start or repeated Start detected.
1: Start or repeated Start detected.
STO: SMBus Stop Flag.
Write:
0: No STOP condition is transmitted.
1: Setting STO to logic ‘1’ causes a STOP condition to be transmitted after the next ACK
cycle. When the STOP condition is generated, hardware clears STO to logic ‘0’. If both
STA and STO are set, a STOP condition is transmitted followed by a START condition.
Read:
0: No Stop condition detected.
1: Stop condition detected (if in Slave Mode) or pending (if in Master Mode).
ACKRQ: SMBus Acknowledge Request
This read-only bit is set to logic ‘1’ when the SMBus has received a byte and needs the ACK
bit to be written with the correct ACK response value.
ARBLOST: SMBus Arbitration Lost Indicator.
This read-only bit is set to logic ‘1’ when the SMBus loses arbitration while operating as a
transmitter. A lost arbitration while a slave indicates a bus error condition.
ACK: SMBus Acknowledge Flag.
This bit defines the out-going ACK level and records incoming ACK levels. It should be written each time a byte is received (when ACKRQ=1), or read after each byte is transmitted.
0: A "not acknowledge" has been received (if in Transmitter Mode) OR will be transmitted (if
in Receiver Mode).
1: An "acknowledge" has been received (if in Transmitter Mode) OR will be transmitted (if in
Receiver Mode).
SI: SMBus Interrupt Flag.
This bit is set by hardware under the conditions listed in Table 18.3. SI must be cleared by
software. While SI is set, SCL is held low and the SMBus is stalled.
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Table 18.3. Sources for Hardware Changes to SMB0CN
Bit
Set by Hardware When:
MASTER
• A START is generated.
TXMODE
• START is generated.
• SMB0DAT is written before the start of an
SMBus frame.
STA
STO
ACKRQ
ARBLOST
ACK
SI
212
• A START followed by an address byte is
received.
• A STOP is detected while addressed as a
slave.
• Arbitration is lost due to a detected STOP.
• A byte has been received and an ACK
response value is needed.
• A repeated START is detected as a MASTER
when STA is low (unwanted repeated START).
• SCL is sensed low while attempting to generate a STOP or repeated START condition.
• SDA is sensed low while transmitting a ‘1’
(excluding ACK bits).
• The incoming ACK value is low
(ACKNOWLEDGE).
• A START has been generated.
• Lost arbitration.
• A byte has been transmitted and an
ACK/NACK received.
• A byte has been received.
• A START or repeated START followed by a
slave address + R/W has been received.
• A STOP has been received.
Rev. 1.2
Cleared by Hardware When:
• A STOP is generated.
• Arbitration is lost.
• A START is detected.
• Arbitration is lost.
• SMB0DAT is not written before the
start of an SMBus frame.
• Must be cleared by software.
• A pending STOP is generated.
• After each ACK cycle.
• Each time SI is cleared.
• The incoming ACK value is high (NOT
ACKNOWLEDGE).
• Must be cleared by software.
C8051F360/1/2/3/4/5/6/7/8/9
18.4.3. Data Register
The SMBus Data register SMB0DAT holds a byte of serial data to be transmitted or one that has just been
received. Software may safely read or write to the data register when the SI flag is set. Software should not
attempt to access the SMB0DAT register when the SMBus is enabled and the SI flag is cleared to logic ‘0’,
as the interface may be in the process of shifting a byte of data into or out of the register.
Data in SMB0DAT is always shifted out MSB first. After a byte has been received, the first bit of received
data is located at the MSB of SMB0DAT. While data is being shifted out, data on the bus is simultaneously
being shifted in. SMB0DAT always contains the last data byte present on the bus. In the event of lost arbitration, the transition from master transmitter to slave receiver is made with the correct data or address in
SMB0DAT.
SFR Definition 18.3. SMB0DAT: SMBus Data
SFR Page:
all pages
SFR Address: 0xC2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
Bits 7–0: SMB0DAT: SMBus Data.
The SMB0DAT register contains a byte of data to be transmitted on the SMBus serial interface or a byte that has just been received on the SMBus serial interface. The CPU can read
from or write to this register whenever the SI serial interrupt flag (SMB0CN.0) is set to
logic ‘1’. The serial data in the register remains stable as long as the SI flag is set. When the
SI flag is not set, the system may be in the process of shifting data in/out and the CPU
should not attempt to access this register.
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18.5. SMBus Transfer Modes
The SMBus interface may be configured to operate as master and/or slave. At any particular time, it will be
operating in one of the following four modes: Master Transmitter, Master Receiver, Slave Transmitter, or
Slave Receiver. The SMBus interface enters Master Mode any time a START is generated, and remains in
Master Mode until it loses an arbitration or generates a STOP. An SMBus interrupt is generated at the end
of all SMBus byte frames; however, note that the interrupt is generated before the ACK cycle when operating as a receiver, and after the ACK cycle when operating as a transmitter.
18.5.1. Master Transmitter Mode
Serial data is transmitted on SDA while the serial clock is output on SCL. The SMBus interface generates
the START condition and transmits the first byte containing the address of the target slave and the data
direction bit. In this case the data direction bit (R/W) will be logic ‘0’ (WRITE). The master then transmits
one or more bytes of serial data. After each byte is transmitted, an acknowledge bit is generated by the
slave. The transfer is ended when the STO bit is set and a STOP is generated. Note that the interface will
switch to Master Receiver Mode if SMB0DAT is not written following a Master Transmitter interrupt.
Figure 18.5 shows a typical Master Transmitter sequence. Two transmit data bytes are shown, though any
number of bytes may be transmitted. Notice that the ‘data byte transferred’ interrupts occur after the ACK
cycle in this mode.
S
SLA
W
Interrupt
A
Data Byte
Interrupt
A
Data Byte
Interrupt
A
P
Interrupt
S = START
P = STOP
A = ACK
W = WRITE
SLA = Slave Address
Received by SMBus
Interface
Transmitted by
SMBus Interface
Figure 18.5. Typical Master Transmitter Sequence
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18.5.2. Master Receiver Mode
Serial data is received on SDA while the serial clock is output on SCL. The SMBus interface generates the
START condition and transmits the first byte containing the address of the target slave and the data direction bit. In this case the data direction bit (R/W) will be logic ‘1’ (READ). Serial data is then received from
the slave on SDA while the SMBus outputs the serial clock. The slave transmits one or more bytes of serial
data. After each byte is received, ACKRQ is set to ‘1’ and an interrupt is generated. Software must write
the ACK bit (SMB0CN.1) to define the outgoing acknowledge value (Note: writing a ‘1’ to the ACK bit generates an ACK; writing a ‘0’ generates a NACK). Software should write a ‘0’ to the ACK bit after the last
byte is received, to transmit a NACK. The interface exits Master Receiver Mode after the STO bit is set and
a STOP is generated. The interface will switch to Master Transmitter Mode if SMB0DAT is written while an
active Master Receiver. Figure 18.6 shows a typical Master Receiver sequence. Two received data bytes
are shown, though any number of bytes may be received. Notice that the ‘data byte transferred’ interrupts
occur before the ACK cycle in this mode.
S
SLA
R
Interrupt
A
Interrupt
Data Byte
A
Interrupt
Data Byte
N
P
Interrupt
S = START
P = STOP
A = ACK
N = NACK
R = READ
SLA = Slave Address
Received by SMBus
Interface
Transmitted by
SMBus Interface
Figure 18.6. Typical Master Receiver Sequence
Rev. 1.2
215
C8051F360/1/2/3/4/5/6/7/8/9
18.5.3. Slave Receiver Mode
Serial data is received on SDA and the clock is received on SCL. When slave events are enabled (INH =
0), the interface enters Slave Receiver Mode when a START followed by a slave address and direction bit
(WRITE in this case) is received. Upon entering Slave Receiver Mode, an interrupt is generated and the
ACKRQ bit is set. Software responds to the received slave address with an ACK, or ignores the received
slave address with a NACK. If the received slave address is ignored, slave interrupts will be inhibited until
the next START is detected. If the received slave address is acknowledged, zero or more data bytes are
received. Software must write the ACK bit after each received byte to ACK or NACK the received byte. The
interface exits Slave Receiver Mode after receiving a STOP. Note that the interface will switch to Slave
Transmitter Mode if SMB0DAT is written while an active Slave Receiver. Figure 18.7 shows a typical Slave
Receiver sequence. Two received data bytes are shown, though any number of bytes may be received.
Notice that the ‘data byte transferred’ interrupts occur before the ACK cycle in this mode.
Interrupt
S
SLA
W
A
Interrupt
Data Byte
A
Interrupt
Data Byte
A
P
Interrupt
S = START
P = STOP
A = ACK
W = WRITE
SLA = Slave Address
Received by SMBus
Interface
Transmitted by
SMBus Interface
Figure 18.7. Typical Slave Receiver Sequence
216
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
18.5.4. Slave Transmitter Mode
Serial data is transmitted on SDA and the clock is received on SCL. When slave events are enabled (INH
= 0), the interface enters Slave Receiver Mode (to receive the slave address) when a START followed by a
slave address and direction bit (READ in this case) is received. Upon entering Slave Transmitter Mode, an
interrupt is generated and the ACKRQ bit is set. Software responds to the received slave address with an
ACK, or ignores the received slave address with a NACK. If the received slave address is ignored, slave
interrupts will be inhibited until a START is detected. If the received slave address is acknowledged, data
should be written to SMB0DAT to be transmitted. The interface enters Slave Transmitter Mode, and transmits one or more bytes of data. After each byte is transmitted, the master sends an acknowledge bit; if the
acknowledge bit is an ACK, SMB0DAT should be written with the next data byte. If the acknowledge bit is
a NACK, SMB0DAT should not be written to before SI is cleared (Note: an error condition may be generated if SMB0DAT is written following a received NACK while in Slave Transmitter Mode). The interface
exits Slave Transmitter Mode after receiving a STOP. Note that the interface will switch to Slave Receiver
Mode if SMB0DAT is not written following a Slave Transmitter interrupt. Figure 18.8 shows a typical Slave
Transmitter sequence. Two transmitted data bytes are shown, though any number of bytes may be transmitted. Notice that the ‘data byte transferred’ interrupts occur after the ACK cycle in this mode.
Interrupt
S
SLA
R
A
Interrupt
Received by SMBus
Interface
Transmitted by
SMBus Interface
Data Byte
A
Data Byte
Interrupt
N
P
Interrupt
S = START
P = STOP
N = NACK
R = READ
SLA = Slave Address
Figure 18.8. Typical Slave Transmitter Sequence
Rev. 1.2
217
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18.6. SMBus Status Decoding
The current SMBus status can be easily decoded using the SMB0CN register. In the table below, STATUS
VECTOR refers to the four upper bits of SMB0CN: MASTER, TXMODE, STA, and STO. The shown
response options are only the typical responses; application-specific procedures are allowed as long as
they conform to the SMBus specification. Highlighted responses are allowed but do not conform to the
SMBus specification.
Table 18.4. SMBus Status Decoding
Values
Written
218
ACKRQ
ARBLOST
0
0
X A master START was generated.
0
0
0
ACK
Load slave address + R/W
into SMB0DAT.
0
0
X
Set STA to restart transfer.
A master data or address byte
was transmitted; NACK received. Abort transfer.
1
0
X
0
1
X
Load next data byte into
SMB0DAT.
0
0
X
End transfer with STOP.
0
1
X
End transfer with STOP and
start another transfer.
1
1
X
Send repeated START.
1
0
X
Switch to Master Receiver
Mode (clear SI without writing new data to SMB0DAT).
0
0
X
1100
0
0
1
Typical Response Options
STo
ACK
Status
Vector
1110
Current SMbus State
STA
Master Transmitter
Mode
Values Read
A master data or address byte
was transmitted; ACK received.
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
Table 18.4. SMBus Status Decoding (Continued)
Values
Written
Slave Transmitter
0100
0101
ACK
X
ACK
0
Typical Response Options
STo
1
ARBLOST
ACKRQ
Status
Vector
1000
Current SMbus State
STA
Master Receiver
Mode
Values Read
Acknowledge received byte;
Read SMB0DAT.
0
0
1
Send NACK to indicate last
byte, and send STOP.
0
1
0
Send NACK to indicate last
byte, and send STOP followed by START.
1
1
0
Send ACK followed by
repeated START.
1
0
1
1
0
0
Send ACK and switch to
Master Transmitter Mode
(write to SMB0DAT before
clearing SI).
0
0
1
Send NACK and switch to
Master Transmitter Mode
(write to SMB0DAT before
clearing SI).
0
0
0
A master data byte was received; Send NACK to indicate last
ACK requested.
byte, and send repeated
START.
0
0
0
A slave byte was transmitted;
NACK received.
No action required (expecting STOP condition).
0
0
X
0
0
1
A slave byte was transmitted;
ACK received.
Load SMB0DAT with next
data byte to transmit.
0
0
X
0
1
X
A Slave byte was transmitted;
error detected.
No action required (expecting Master to end transfer).
0
0
X
0
X
X
A STOP was detected while an
addressed Slave Transmitter.
No action required (transfer
complete).
0
0
X
Rev. 1.2
219
C8051F360/1/2/3/4/5/6/7/8/9
Table 18.4. SMBus Status Decoding (Continued)
Values
Written
Slave Receiver
0001
1
ACK
Lost arbitration as master; slave
X address received; ACK
requested.
Acknowledge received
address.
0
0
1
Do not acknowledge
received address.
0
0
0
Acknowledge received
address.
0
0
1
Do not acknowledge
received address.
0
0
0
Reschedule failed transfer;
do not acknowledge received
address.
1
0
0
0
1
X
Lost arbitration while attempting a Abort failed transfer.
repeated START.
Reschedule failed transfer.
0
0
X
1
0
X
1
1
X
Lost arbitration while attempting a No action required (transfer
STOP.
complete/aborted).
0
0
0
0
0
X
A STOP was detected while an
addressed slave receiver.
0
0
X
0
1
X
Lost arbitration due to a detected Abort transfer.
STOP.
Reschedule failed transfer.
0
0
X
1
0
X
Acknowledge received byte;
Read SMB0DAT.
0
0
1
Do not acknowledge
received byte.
0
0
0
0
0
0
1
0
0
1
0
A slave byte was received; ACK
X
requested.
1
1
X
0000
220
ACK
1
A slave address was received;
X
ACK requested.
Typical Response Options
STo
0010
0
Current SMbus State
STA
1
ARBLOST
ACKRQ
Status
Vector
Mode
Values Read
No action required (transfer
complete).
Lost arbitration while transmitting Abort failed transfer.
a data byte as master.
Reschedule failed transfer.
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
19. UART0
UART0 is an asynchronous, full duplex serial port offering modes 1 and 3 of the standard 8051 UART.
Enhanced baud rate support allows a wide range of clock sources to generate standard baud rates (details
in Section “19.1. Enhanced Baud Rate Generation” on page 222). Received data buffering allows UART0
to start reception of a second incoming data byte before software has finished reading the previous data
byte.
UART0 has two associated SFRs: Serial Control Register 0 (SCON0) and Serial Data Buffer 0 (SBUF0).
The single SBUF0 location provides access to both transmit and receive registers. Writes to SBUF0
always access the Transmit register. Reads of SBUF0 always access the buffered Receive register;
it is not possible to read data from the Transmit register.
With UART0 interrupts enabled, an interrupt is generated each time a transmit is completed (TI0 is set in
SCON0), or a data byte has been received (RI0 is set in SCON0). The UART0 interrupt flags are not
cleared by hardware when the CPU vectors to the interrupt service routine. They must be cleared manually
by software, allowing software to determine the cause of the UART0 interrupt (transmit complete or receive
complete).
SFR Bus
Write to
SBUF
TB8
SBUF
(TX Shift)
SET
D
Q
TX
CLR
Crossbar
Zero Detector
Stop Bit
Shift
Start
Data
Tx Control
Tx Clock
Send
Tx IRQ
TI
MCE
REN
TB8
RB8
TI
RI
SMODE
SCON
UART Baud
Rate Generator
RI
Serial
Port
Interrupt
Port I/O
Rx IRQ
Rx Clock
Rx Control
Start
Shift
0x1FF
Load
SBUF
RB8
Input Shift Register
(9 bits)
Load SBUF
SBUF
(RX Latch)
Read
SBUF
SFR Bus
RX
Crossbar
Figure 19.1. UART0 Block Diagram
Rev. 1.2
221
C8051F360/1/2/3/4/5/6/7/8/9
19.1. Enhanced Baud Rate Generation
The UART0 baud rate is generated by Timer 1 in 8-bit auto-reload mode. The TX clock is generated by
TL1; the RX clock is generated by a copy of TL1 (shown as RX Timer in Figure 19.2), which is not useraccessible. Both TX and RX Timer overflows are divided by two to generate the TX and RX baud rates.
The RX Timer runs when Timer 1 is enabled, and uses the same reload value (TH1). However, an
RX Timer reload is forced when a START condition is detected on the RX pin. This allows a receive to
begin any time a START is detected, independent of the TX Timer state.
Timer 1
TL1
UART
Overflow
2
TX Clock
Overflow
2
RX Clock
TH1
Start
Detected
RX Timer
Figure 19.2. UART0 Baud Rate Logic
Timer 1 should be configured for Mode 2, 8-bit auto-reload (see Section “21.1.3. Mode 2: 8-bit
Counter/Timer with Auto-Reload” on page 250). The Timer 1 reload value should be set so that overflows
will occur at two times the desired UART baud rate frequency. Note that Timer 1 may be clocked by one of
six sources: SYSCLK, SYSCLK / 4, SYSCLK / 12, SYSCLK / 48, the external oscillator clock / 8, or an
external input T1. For any given Timer 1 clock source, the UART0 baud rate is determined by
Equation 19.1-A and Equation 19.1-B.
A)
1
UartBaudRate = --- T1_Overflow_Rate
2
B)
T1 CLK
T1_Overflow_Rate = -------------------------256 – TH1
Equation 19.1. UART0 Baud Rate
Where T1CLK is the frequency of the clock supplied to Timer 1, and T1H is the high byte of Timer 1 (reload
value). Timer 1 clock frequency is selected as described in Section “21. Timers” on page 248. A quick reference for typical baud rates and system clock frequencies is given in Table 19.1 through Table 19.6. Note
that the internal oscillator may still generate the system clock when the external oscillator is driving Timer
1.
222
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19.2. Operational Modes
UART0 provides standard asynchronous, full duplex communication. The UART mode (8-bit or 9-bit) is
selected by the S0MODE bit (SCON0.7). Typical UART connection options are shown below.
TX
RS-232
LEVEL
XLTR
RS-232
RX
C8051Fxxx
OR
TX
TX
RX
RX
MCU
C8051Fxxx
Figure 19.3. UART Interconnect Diagram
19.2.1. 8-Bit UART
8-Bit UART mode uses a total of 10 bits per data byte: one start bit, eight data bits (LSB first), and one stop
bit. Data are transmitted LSB first from the TX0 pin and received at the RX0 pin. On receive, the eight data
bits are stored in SBUF0 and the stop bit goes into RB80 (SCON0.2).
Data transmission begins when software writes a data byte to the SBUF0 register. The TI0 Transmit Interrupt Flag (SCON0.1) is set at the end of the transmission (the beginning of the stop-bit time). Data reception can begin any time after the REN0 Receive Enable bit (SCON0.4) is set to logic ‘1’. After the stop bit is
received, the data byte will be loaded into the SBUF0 receive register if the following conditions are met:
RI0 must be logic ‘0’, and if MCE0 is logic ‘1’, the stop bit must be logic ‘1’. In the event of a receive data
overrun, the first received 8 bits are latched into the SBUF0 receive register and the following overrun data
bits are lost.
If these conditions are met, the eight bits of data is stored in SBUF0, the stop bit is stored in RB80 and the
RI0 flag is set. If these conditions are not met, SBUF0 and RB80 will not be loaded and the RI0 flag will not
be set. An interrupt will occur if enabled when either TI0 or RI0 is set.
MARK
SPACE
START
BIT
D0
D1
D2
D3
D4
D5
D6
D7
STOP
BIT
BIT TIMES
BIT SAMPLING
Figure 19.4. 8-Bit UART Timing Diagram
Rev. 1.2
223
C8051F360/1/2/3/4/5/6/7/8/9
19.2.2. 9-Bit UART
9-bit UART mode uses a total of eleven bits per data byte: a start bit, 8 data bits (LSB first), a programmable ninth data bit, and a stop bit. The state of the ninth transmit data bit is determined by the value in TB80
(SCON0.3), which is assigned by user software. It can be assigned the value of the parity flag (bit P in register PSW) for error detection, or used in multiprocessor communications. On receive, the ninth data bit
goes into RB80 (SCON0.2) and the stop bit is ignored.
Data transmission begins when an instruction writes a data byte to the SBUF0 register. The TI0 Transmit
Interrupt Flag (SCON0.1) is set at the end of the transmission (the beginning of the stop-bit time). Data
reception can begin any time after the REN0 Receive Enable bit (SCON0.4) is set to ‘1’. After the stop bit
is received, the data byte will be loaded into the SBUF0 receive register if the following conditions are met:
(1) RI0 must be logic ‘0’, and (2) if MCE0 is logic ‘1’, the 9th bit must be logic ‘1’ (when MCE0 is logic ‘0’,
the state of the ninth data bit is unimportant). If these conditions are met, the eight bits of data are stored in
SBUF0, the ninth bit is stored in RB80, and the RI0 flag is set to ‘1’. If the above conditions are not met,
SBUF0 and RB80 will not be loaded and the RI0 flag will not be set to ‘1’. A UART0 interrupt will occur if
enabled when either TI0 or RI0 is set to ‘1’.
MARK
SPACE
START
BIT
D0
D1
D2
D3
D4
D5
D6
BIT TIMES
BIT SAMPLING
Figure 19.5. 9-Bit UART Timing Diagram
224
Rev. 1.2
D7
D8
STOP
BIT
C8051F360/1/2/3/4/5/6/7/8/9
19.3. Multiprocessor Communications
9-Bit UART mode supports multiprocessor communication between a master processor and one or more
slave processors by special use of the ninth data bit. When a master processor wants to transmit to one or
more slaves, it first sends an address byte to select the target(s). An address byte differs from a data byte
in that its ninth bit is logic ‘1’; in a data byte, the ninth bit is always set to logic ‘0’.
Setting the MCE0 bit (SCON0.5) of a slave processor configures its UART such that when a stop bit is
received, the UART will generate an interrupt only if the ninth bit is logic ‘1’ (RB80 = 1) signifying an
address byte has been received. In the UART interrupt handler, software will compare the received
address with the slave's own assigned 8-bit address. If the addresses match, the slave will clear its MCE0
bit to enable interrupts on the reception of the following data byte(s). Slaves that weren't addressed leave
their MCE0 bits set and do not generate interrupts on the reception of the following data bytes, thereby
ignoring the data. Once the entire message is received, the addressed slave resets its MCE0 bit to ignore
all transmissions until it receives the next address byte.
Multiple addresses can be assigned to a single slave and/or a single address can be assigned to multiple
slaves, thereby enabling "broadcast" transmissions to more than one slave simultaneously. The master
processor can be configured to receive all transmissions or a protocol can be implemented such that the
master/slave role is temporarily reversed to enable half-duplex transmission between the original master
and slave(s).
Master
Device
RX
TX
Slave
Device
RX
TX
Slave
Device
RX
TX
Slave
Device
RX
V+
TX
Figure 19.6. UART Multi-Processor Mode Interconnect Diagram
Rev. 1.2
225
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 19.1. SCON0: Serial Port 0 Control
SFR Page:
all pages
SFR Address: 0x98
(bit addressable)
R/W
R
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
S0MODE
–
MCE0
REN0
TB80
RB80
TI0
RI0
01000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
226
S0MODE: Serial Port 0 Operation Mode.
This bit selects the UART0 Operation Mode.
0: 8-bit UART with Variable Baud Rate.
1: 9-bit UART with Variable Baud Rate.
UNUSED. Read = 1b. Write = don’t care.
MCE0: Multiprocessor Communication Enable.
The function of this bit is dependent on the Serial Port 0 Operation Mode.
S0MODE = 0: Checks for valid stop bit.
0: Logic level of stop bit is ignored.
1: RI0 will only be activated if stop bit is logic level ‘1’.
S0MODE = 1: Multiprocessor Communications Enable.
0: Logic level of ninth bit is ignored.
1: RI0 is set and an interrupt is generated only when the ninth bit is logic ‘1’.
REN0: Receive Enable.
This bit enables/disables the UART receiver.
0: UART0 reception disabled.
1: UART0 reception enabled.
TB80: Ninth Transmission Bit.
The logic level of this bit will be assigned to the ninth transmission bit in 9-bit UART Mode. It
is not used in 8-bit UART Mode. Set or cleared by software as required.
RB80: Ninth Receive Bit.
RB80 is assigned the value of the STOP bit in Mode 0; it is assigned the value of the 9th
data bit in Mode 1.
TI0: Transmit Interrupt Flag.
Set by hardware when a byte of data has been transmitted by UART0 (after the 8th bit in 8bit UART Mode, or at the beginning of the STOP bit in 9-bit UART Mode). When the UART0
interrupt is enabled, setting this bit causes the CPU to vector to the UART0 interrupt service
routine. This bit must be cleared manually by software.
RI0: Receive Interrupt Flag.
Set to ‘1’ by hardware when a byte of data has been received by UART0 (set at the STOP bit
sampling time). When the UART0 interrupt is enabled, setting this bit to ‘1’ causes the CPU
to vector to the UART0 interrupt service routine. This bit must be cleared manually by software.
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 19.2. SBUF0: Serial (UART0) Port Data Buffer
SFR Page:
all pages
SFR Address: 0x99
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: SBUF0[7:0]: Serial Data Buffer Bits 7–0 (MSB–LSB)
This SFR accesses two registers; a transmit shift register and a receive latch register. When
data is written to SBUF0, it goes to the transmit shift register and is held for serial transmission. Writing a byte to SBUF0 initiates the transmission. A read of SBUF0 returns the contents of the receive latch.
Rev. 1.2
227
C8051F360/1/2/3/4/5/6/7/8/9
Table 19.1. Timer Settings for Standard Baud Rates
Using The Internal 24.5 MHz Oscillator
SYSCLK from
Internal Osc.
Frequency: 24.5 MHz
Target
Baud Rate
(bps)
Baud Rate
% Error
Oscillator Divide
Factor
Timer Clock
SCA1–SCA0
T1M1
1
Source
(pre-scale select)
230400
–0.32%
106
SYSCLK
XX2
1
0xCB
115200
–0.32%
212
SYSCLK
XX
1
0x96
57600
0.15%
426
SYSCLK
XX
1
0x2B
28800
–0.32%
848
SYSCLK/4
01
0
0x96
14400
0.15%
1704
SYSCLK/12
00
0
0xB9
9600
–0.32%
2544
SYSCLK/12
00
0
0x96
2400
–0.32%
10176
SYSCLK/48
10
0
0x96
1200
0.15%
20448
SYSCLK/48
10
0
0x2B
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
228
Timer 1
Reload
Value (hex)
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SYSCLK from Internal Osc.,
SYSCLK and Timer Clock
Timer Clock from External Osc. from External Osc.
Table 19.2. Timer Settings for Standard Baud Rates
Using an External 25.0 MHz Oscillator
Frequency: 25.0 MHz
Oscilla- Timer Clock
SCA1–SCA0
Timer 1
T1M1
1
tor Divide
Source
Reload
(pre-scale select)
Factor
Value (hex)
1
0xCA
108
SYSCLK
XX2
Target
Baud Rate
(bps)
230400
Baud Rate
% Error
115200
0.45%
218
SYSCLK
XX
1
0x93
57600
–0.01%
434
SYSCLK
XX
1
0x27
28800
0.45%
872
SYSCLK/4
01
0
0x93
14400
–0.01%
1736
SYSCLK/4
01
0
0x27
9600
0.15%
2608
EXTCLK/8
11
0
0x5D
–0.47%
2400
0.45%
10464
SYSCLK/48
10
0
0x93
1200
–0.01%
20832
SYSCLK/48
10
0
0x27
57600
–0.47%
432
EXTCLK/8
11
0
0xE5
28800
–0.47%
864
EXTCLK/8
11
0
0xCA
14400
0.45%
1744
EXTCLK/8
11
0
0x93
9600
0.15%
2608
EXTCLK/8
11
0
0x5D
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
Rev. 1.2
229
C8051F360/1/2/3/4/5/6/7/8/9
SYSCLK from Internal Osc.,
SYSCLK and Timer Clock
Timer Clock from External Osc. from External Osc.
Table 19.3. Timer Settings for Standard Baud Rates
Using an External 22.1184 MHz Oscillator
Frequency: 22.1184 MHz
Oscilla- Timer Clock
SCA1–SCA0
Timer 1
T1M1
1
tor Divide
Source
Reload
(pre-scale select)
Factor
Value (hex)
1
0xD0
96
SYSCLK
XX2
Target
Baud Rate
(bps)
230400
Baud Rate
% Error
115200
0.00%
192
SYSCLK
XX
1
0xA0
57600
0.00%
384
SYSCLK
XX
1
0x40
28800
0.00%
768
SYSCLK/12
00
0
0xE0
14400
0.00%
1536
SYSCLK/12
00
0
0xC0
9600
0.00%
2304
SYSCLK/12
00
0
0xA0
2400
0.00%
9216
SYSCLK/48
10
0
0xA0
1200
0.00%
18432
SYSCLK/48
10
0
0x40
230400
0.00%
96
EXTCLK/8
11
0
0xFA
115200
0.00%
192
EXTCLK/8
11
0
0xF4
57600
0.00%
384
EXTCLK/8
11
0
0xE8
28800
0.00%
768
EXTCLK/8
11
0
0xD0
14400
0.00%
1536
EXTCLK/8
11
0
0xA0
9600
0.00%
2304
EXTCLK/8
11
0
0x70
0.00%
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
230
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SYSCLK from Internal Osc.,
SYSCLK and Timer Clock
Timer Clock from External Osc. from External Osc.
Table 19.4. Timer Settings for Standard Baud Rates
Using an External 18.432 MHz Oscillator
Frequency: 18.432 MHz
Oscilla- Timer Clock
SCA1–SCA0
Timer 1
T1M1
1
tor Divide
Source
Reload
(pre-scale select)
Factor
Value (hex)
1
0xD8
80
SYSCLK
XX2
Target
Baud Rate
(bps)
230400
Baud Rate
% Error
115200
0.00%
160
SYSCLK
XX
1
0xB0
57600
0.00%
320
SYSCLK
XX
1
0x60
28800
0.00%
640
SYSCLK/4
01
0
0xB0
14400
0.00%
1280
SYSCLK/4
01
0
0x60
9600
0.00%
1920
SYSCLK/12
00
0
0xB0
0.00%
2400
0.00%
7680
SYSCLK/48
10
0
0xB0
1200
0.00%
15360
SYSCLK/48
10
0
0x60
230400
0.00%
80
EXTCLK/8
11
0
0xFB
115200
0.00%
160
EXTCLK/8
11
0
0xF6
57600
0.00%
320
EXTCLK/8
11
0
0xEC
28800
0.00%
640
EXTCLK/8
11
0
0xD8
14400
0.00%
1280
EXTCLK/8
11
0
0xB0
9600
0.00%
1920
EXTCLK/8
11
0
0x88
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
Rev. 1.2
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C8051F360/1/2/3/4/5/6/7/8/9
SYSCLK from Internal Osc.,
SYSCLK and Timer Clock
Timer Clock from External Osc. from External Osc.
Table 19.5. Timer Settings for Standard Baud Rates
Using an External 11.0592 MHz Oscillator
Frequency: 11.0592 MHz
Oscilla- Timer Clock
SCA1–SCA0
Timer 1
T1M1
1
tor Divide
Source
Reload
(pre-scale select)
Factor
Value (hex)
1
0xE8
48
SYSCLK
XX2
Target
Baud Rate
(bps)
230400
Baud Rate
% Error
115200
0.00%
96
SYSCLK
XX
1
0xD0
57600
0.00%
192
SYSCLK
XX
1
0xA0
28800
0.00%
384
SYSCLK
XX
1
0x40
14400
0.00%
768
SYSCLK/12
00
0
0xE0
9600
0.00%
1152
SYSCLK/12
00
0
0xD0
0.00%
2400
0.00%
4608
SYSCLK/12
00
0
0x40
1200
0.00%
9216
SYSCLK/48
10
0
0xA0
230400
0.00%
48
EXTCLK/8
11
0
0xFD
115200
0.00%
96
EXTCLK/8
11
0
0xFA
57600
0.00%
192
EXTCLK/8
11
0
0xF4
28800
0.00%
384
EXTCLK/8
11
0
0xE8
14400
0.00%
768
EXTCLK/8
11
0
0xD0
9600
0.00%
1152
EXTCLK/8
11
0
0xB8
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
232
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SYSCLK from Internal Osc.,
SYSCLK and Timer Clock
Timer Clock from External Osc. from External Osc.
Table 19.6. Timer Settings for Standard Baud Rates
Using an External 3.6864 MHz Oscillator
Frequency: 3.6864 MHz
Oscilla- Timer Clock
SCA1–SCA0
Timer 1
T1M1
1
tor Divide
Source
Reload
(pre-scale select)
Factor
Value (hex)
1
0xF8
16
SYSCLK
XX2
Target
Baud Rate
(bps)
230400
Baud
Rate%
Error
0.00%
115200
0.00%
32
SYSCLK
XX
1
0xF0
57600
0.00%
64
SYSCLK
XX
1
0xE0
28800
0.00%
128
SYSCLK
XX
1
0xC0
14400
0.00%
256
SYSCLK
XX
1
0x80
9600
0.00%
384
SYSCLK
XX
1
0x40
2400
0.00%
1536
SYSCLK/12
00
0
0xC0
1200
0.00%
3072
SYSCLK/12
00
0
0x80
230400
0.00%
16
EXTCLK/8
11
0
0xFF
115200
0.00%
32
EXTCLK/8
11
0
0xFE
57600
0.00%
64
EXTCLK/8
11
0
0xFC
28800
0.00%
128
EXTCLK/8
11
0
0xF8
14400
0.00%
256
EXTCLK/8
11
0
0xF0
9600
0.00%
384
EXTCLK/8
11
0
0xE8
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
Rev. 1.2
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Table 19.7. Timer Settings for Standard Baud Rates Using the PLL
Frequency: 50.0 MHz
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
Baud Rate
% Error
0.45%
–0.01%
0.45%
–0.01%
0.22%
–0.01%
–0.01%
Oscillator Divide
Factor
218
434
872
1736
3480
5208
20832
Timer Clock
SCA1-SCA0
T1M1
1
Source
(pre-scale select)
SYSCLK
SYSCLK
SYSCLK/4
SYSCLK/4
SYSCLK/12
SYSCLK/12
SYSCLK/48
XX2
XX
01
01
00
00
10
1
1
0
0
0
0
0
Timer 1
Reload
Value (hex)
0x93
0x27
0x93
0x27
0x6F
0x27
0x27
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
Table 19.8. Timer Settings for Standard Baud Rates Using the PLL
Frequency: 100.0 MHz
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
Baud Rate
% Error
–0.01%
0.45%
–0.01%
0.22%
–0.47%
0.45%
Oscillator Divide
Factor
434
872
1736
3480
6912
10464
Timer Clock
SCA1-SCA0
T1M1
1
Source
(pre-scale select)
SYSCLK
SYSCLK/4
SYSCLK/4
SYSCLK/12
SYSCLK/48
SYSCLK/48
XX2
01
01
00
10
10
Notes:
1. SCA1–SCA0 and T1M bit definitions can be found in Section 21.1.
2. X = Don’t care.
234
Rev. 1.2
1
0
0
0
0
0
Timer 1
Reload
Value (hex)
0x27
0x93
0x27
0x6F
0xB8
0x93
C8051F360/1/2/3/4/5/6/7/8/9
20. Enhanced Serial Peripheral Interface (SPI0)
The Enhanced Serial Peripheral Interface (SPI0) provides access to a flexible, full-duplex synchronous
serial bus. SPI0 can operate as a master or slave device in both 3-wire or 4-wire modes, and supports multiple masters and slaves on a single SPI bus. The slave-select (NSS) signal can be configured as an input
to select SPI0 in slave mode, or to disable Master Mode operation in a multi-master environment, avoiding
contention on the SPI bus when more than one master attempts simultaneous data transfers. NSS can
also be configured as a chip-select output in master mode, or disabled for 3-wire operation. Additional general purpose port I/O pins can be used to select multiple slave devices in master mode.
SFR Bus
SYSCLK
SPI0CN
SPIBSY
MSTEN
CKPHA
CKPOL
SLVSEL
NSSIN
SRMT
RXBMT
SPIF
WCOL
MODF
RXOVRN
NSSMD1
NSSMD0
TXBMT
SPIEN
SPI0CFG
SCR7
SCR6
SCR5
SCR4
SCR3
SCR2
SCR1
SCR0
SPI0CKR
Clock Divide
Logic
SPI CONTROL LOGIC
Data Path
Control
SPI IRQ
Pin Interface
Control
MOSI
Tx Data
SPI0DAT
SCK
Transmit Data Buffer
Shift Register
7 6 5 4 3 2 1 0
Rx Data
Pin
Control
Logic
Receive Data Buffer
MISO
C
R
O
S
S
B
A
R
Port I/O
NSS
Read
SPI0DAT
Write
SPI0DAT
SFR Bus
Figure 20.1. SPI Block Diagram
Rev. 1.2
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20.1. Signal Descriptions
The four signals used by SPI0 (MOSI, MISO, SCK, NSS) are described below.
20.1.1. Master Out, Slave In (MOSI)
The master-out, slave-in (MOSI) signal is an output from a master device and an input to slave devices. It
is used to serially transfer data from the master to the slave. This signal is an output when SPI0 is operating as a master and an input when SPI0 is operating as a slave. Data is transferred most-significant bit
first. When configured as a master, MOSI is driven by the MSB of the shift register in both 3- and 4-wire
mode.
20.1.2. Master In, Slave Out (MISO)
The master-in, slave-out (MISO) signal is an output from a slave device and an input to the master device.
It is used to serially transfer data from the slave to the master. This signal is an input when SPI0 is operating as a master and an output when SPI0 is operating as a slave. Data is transferred most-significant bit
first. The MISO pin is placed in a high-impedance state when the SPI module is disabled and when the SPI
operates in 4-wire mode as a slave that is not selected. When acting as a slave in 3-wire mode, MISO is
always driven by the MSB of the shift register.
20.1.3. Serial Clock (SCK)
The serial clock (SCK) signal is an output from the master device and an input to slave devices. It is used
to synchronize the transfer of data between the master and slave on the MOSI and MISO lines. SPI0 generates this signal when operating as a master. The SCK signal is ignored by a SPI slave when the slave is
not selected (NSS = 1) in 4-wire slave mode.
20.1.4. Slave Select (NSS)
The function of the slave-select (NSS) signal is dependent on the setting of the NSSMD1 and NSSMD0
bits in the SPI0CN register. There are three possible modes that can be selected with these bits:
1. NSSMD[1:0] = 00: 3-Wire Master or 3-Wire Slave Mode: SPI0 operates in 3-wire mode, and
NSS is disabled. When operating as a slave device, SPI0 is always selected in 3-wire mode.
Since no select signal is present, SPI0 must be the only slave on the bus in 3-wire mode. This
is intended for point-to-point communication between a master and one slave.
2. NSSMD[1:0] = 01: 4-Wire Slave or Multi-Master Mode: SPI0 operates in 4-wire mode, and
NSS is enabled as an input. When operating as a slave, NSS selects the SPI0 device. When
operating as a master, a 1-to-0 transition of the NSS signal disables the master function of
SPI0 so that multiple master devices can be used on the same SPI bus.
3. NSSMD[1:0] = 1x: 4-Wire Master Mode: SPI0 operates in 4-wire mode, and NSS is enabled as
an output. The setting of NSSMD0 determines what logic level the NSS pin will output. This
configuration should only be used when operating SPI0 as a master device.
See Figure 20.2, Figure 20.3, and Figure 20.4 for typical connection diagrams of the various operational
modes. Note that the setting of NSSMD bits affects the pinout of the device. When in 3-wire master or
3-wire slave mode, the NSS pin will not be mapped by the crossbar. In all other modes, the NSS signal will
be mapped to a pin on the device. See Section “17. Port Input/Output” on page 184 for general purpose
port I/O and crossbar information.
236
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20.2. SPI0 Master Mode Operation
A SPI master device initiates all data transfers on a SPI bus. SPI0 is placed in master mode by setting the
Master Enable flag (MSTEN, SPI0CN.6). Writing a byte of data to the SPI0 data register (SPI0DAT) when
in master mode writes to the transmit buffer. If the SPI shift register is empty, the byte in the transmit buffer
is moved to the shift register, and a data transfer begins. The SPI0 master immediately shifts out the data
serially on the MOSI line while providing the serial clock on SCK. The SPIF (SPI0CN.7) flag is set to logic
‘1’ at the end of the transfer. If interrupts are enabled, an interrupt request is generated when the SPIF flag
is set. While the SPI0 master transfers data to a slave on the MOSI line, the addressed SPI slave device
simultaneously transfers the contents of its shift register to the SPI master on the MISO line in a full-duplex
operation. Therefore, the SPIF flag serves as both a transmit-complete and receive-data-ready flag. The
data byte received from the slave is transferred MSB-first into the master's shift register. When a byte is
fully shifted into the register, it is moved to the receive buffer where it can be read by the processor by
reading SPI0DAT.
When configured as a master, SPI0 can operate in one of three different modes: multi-master mode, 3-wire
single-master mode, and 4-wire single-master mode. The default, multi-master mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 1. In this mode, NSS is an input to the device, and is
used to disable the master SPI0 when another master is accessing the bus. When NSS is pulled low in this
mode, MSTEN (SPI0CN.6) and SPIEN (SPI0CN.0) are set to 0 to disable the SPI master device, and a
Mode Fault is generated (MODF, SPI0CN.5 = 1). Mode Fault will generate an interrupt if enabled. SPI0
must be manually re-enabled in software under these circumstances. In multi-master systems, devices will
typically default to being slave devices while they are not acting as the system master device. In multi-master mode, slave devices can be addressed individually (if needed) using general-purpose I/O pins.
Figure 20.2 shows a connection diagram between two master devices in multiple-master mode.
3-wire single-master mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 0. In this
mode, NSS is not used, and is not mapped to an external port pin through the crossbar. Any slave devices
that must be addressed in this mode should be selected using general-purpose I/O pins. Figure 20.3
shows a connection diagram between a master device in 3-wire master mode and a slave device.
4-wire single-master mode is active when NSSMD1 (SPI0CN.3) = 1. In this mode, NSS is configured as an
output pin, and can be used as a slave-select signal for a single SPI device. In this mode, the output value
of NSS is controlled (in software) with the bit NSSMD0 (SPI0CN.2). Additional slave devices can be
addressed using general-purpose I/O pins. Figure 20.4 shows a connection diagram for a master device in
4-wire master mode and two slave devices.
Rev. 1.2
237
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Master
Device 1
NSS
GPIO
MISO
MISO
MOSI
MOSI
SCK
SCK
GPIO
NSS
Master
Device 2
Figure 20.2. Multiple-Master Mode Connection Diagram
Master
Device
MISO
MISO
MOSI
MOSI
SCK
SCK
Slave
Device
Figure 20.3. 3-Wire Single Master and 3-Wire Single Slave Mode
Connection Diagram
Master
Device
GPIO
MISO
MISO
MOSI
MOSI
SCK
SCK
NSS
NSS
MISO
MOSI
Slave
Device
Slave
Device
SCK
NSS
Figure 20.4. 4-Wire Single Master Mode and 4-Wire Slave Mode
Connection Diagram
238
Rev. 1.2
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20.3. SPI0 Slave Mode Operation
When SPI0 is enabled and not configured as a master, it will operate as a SPI slave. As a slave, bytes are
shifted in through the MOSI pin and out through the MISO pin by a master device controlling the SCK signal. A bit counter in the SPI0 logic counts SCK edges. When 8 bits have been shifted through the shift register, the SPIF flag is set to logic ‘1’, and the byte is copied into the receive buffer. Data is read from the
receive buffer by reading SPI0DAT. A slave device cannot initiate transfers. Data to be transferred to the
master device is pre-loaded into the shift register by writing to SPI0DAT. Writes to SPI0DAT are doublebuffered, and are placed in the transmit buffer first. If the shift register is empty, the contents of the transmit
buffer will immediately be transferred into the shift register. When the shift register already contains data,
the SPI will load the shift register with the transmit buffer’s contents after the last SCK edge of the next (or
current) SPI transfer.
When configured as a slave, SPI0 can be configured for 4-wire or 3-wire operation. The default, 4-wire
slave mode, is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 1. In 4-wire mode, the
NSS signal is routed to a port pin and configured as a digital input. SPI0 is enabled when NSS is logic ‘0’,
and disabled when NSS is logic ‘1’. The bit counter is reset on a falling edge of NSS. Note that the NSS
signal must be driven low at least 2 system clocks before the first active edge of SCK for each byte transfer. Figure 20.4 shows a connection diagram between two slave devices in 4-wire slave mode and a master device.
3-wire slave mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 0. NSS is not
used in this mode, and is not mapped to an external port pin through the crossbar. Since there is no way of
uniquely addressing the device in 3-wire slave mode, SPI0 must be the only slave device present on the
bus. It is important to note that in 3-wire slave mode there is no external means of resetting the bit counter
that determines when a full byte has been received. The bit counter can only be reset by disabling and reenabling SPI0 with the SPIEN bit. Figure 20.3 shows a connection diagram between a slave device in 3wire slave mode and a master device.
20.4. SPI0 Interrupt Sources
When SPI0 interrupts are enabled, the following four flags will generate an interrupt when they are set to
logic ‘1’:
All of the following bits must be cleared by software.
1. The SPI Interrupt Flag, SPIF (SPI0CN.7) is set to logic ‘1’ at the end of each byte transfer. This
flag can occur in all SPI0 modes.
2. The Write Collision Flag, WCOL (SPI0CN.6) is set to logic ‘1’ if a write to SPI0DAT is
attempted when the transmit buffer has not been emptied to the SPI shift register. When this
occurs, the write to SPI0DAT will be ignored, and the transmit buffer will not be written.This
flag can occur in all SPI0 modes.
3. The Mode Fault Flag MODF (SPI0CN.5) is set to logic ‘1’ when SPI0 is configured as a master, and for multi-master mode and the NSS pin is pulled low. When a Mode Fault occurs, the
MSTEN and SPIEN bits in SPI0CN are set to logic ‘0’ to disable SPI0 and allow another master device to access the bus.
4. The Receive Overrun Flag RXOVRN (SPI0CN.4) is set to logic ‘1’ when configured as a slave,
and a transfer is completed and the receive buffer still holds an unread byte from a previous
transfer. The new byte is not transferred to the receive buffer, allowing the previously received
data byte to be read. The data byte which caused the overrun is lost.
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20.5. Serial Clock Timing
Four combinations of serial clock phase and polarity can be selected using the clock control bits in the
SPI0 Configuration Register (SPI0CFG). The CKPHA bit (SPI0CFG.5) selects one of two clock phases
(edge used to latch the data). The CKPOL bit (SPI0CFG.4) selects between an active-high or active-low
clock. Both master and slave devices must be configured to use the same clock phase and polarity. SPI0
should be disabled (by clearing the SPIEN bit, SPI0CN.0) when changing the clock phase or polarity. The
clock and data line relationships for master mode are shown in Figure 20.5. For slave mode, the clock and
data relationships are shown in Figure 20.6 and Figure 20.7. Note that CKPHA must be set to ‘0’ on both
the master and slave SPI when communicating between two of the following devices: C8051F04x,
C8051F06x, C8051F12x, C8051F31x, C8051F32x, C8051F33x, and C8051F36x.
The SPI0 Clock Rate Register (SPI0CKR) as shown in SFR Definition 20.3 controls the master mode
serial clock frequency. This register is ignored when operating in slave mode. When the SPI is configured
as a master, the maximum data transfer rate (bits/sec) is one-half the system clock frequency or 12.5 MHz,
whichever is slower. When the SPI is configured as a slave, the maximum data transfer rate (bits/sec) for
full-duplex operation is 1/10 the system clock frequency, provided that the master issues SCK, NSS (in 4wire slave mode), and the serial input data synchronously with the slave’s system clock. If the master
issues SCK, NSS, and the serial input data asynchronously, the maximum data transfer rate (bits/sec)
must be less than 1/10 the system clock frequency. In the special case where the master only wants to
transmit data to the slave and does not need to receive data from the slave (i.e. half-duplex operation), the
SPI slave can receive data at a maximum data transfer rate (bits/sec) of 1/4 the system clock frequency.
This is provided that the master issues SCK, NSS, and the serial input data synchronously with the slave’s
system clock.
SCK
(CKPOL=0, CKPHA=0)
SCK
(CKPOL=0, CKPHA=1)
SCK
(CKPOL=1, CKPHA=0)
SCK
(CKPOL=1, CKPHA=1)
MISO/MOSI
MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
NSS (Must Remain High
in Multi-Master Mode)
Figure 20.5. Master Mode Data/Clock Timing
240
Rev. 1.2
Bit 1
Bit 0
C8051F360/1/2/3/4/5/6/7/8/9
SCK
(CKPOL=0, CKPHA=0)
SCK
(CKPOL=1, CKPHA=0)
MOSI
MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
MISO
MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
NSS (4-Wire Mode)
Figure 20.6. Slave Mode Data/Clock Timing (CKPHA = 0)
SCK
(CKPOL=0, CKPHA=1)
SCK
(CKPOL=1, CKPHA=1)
MOSI
MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
MISO
MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 0
NSS (4-Wire Mode)
Figure 20.7. Slave Mode Data/Clock Timing (CKPHA = 1)
Rev. 1.2
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20.6. SPI Special Function Registers
SPI0 is accessed and controlled through four special function registers in the system controller: SPI0CN
Control Register, SPI0DAT Data Register, SPI0CFG Configuration Register, and SPI0CKR Clock Rate
Register. The four special function registers related to the operation of the SPI0 Bus are described in the
following figures.
SFR Definition 20.1. SPI0CFG: SPI0 Configuration
SFR Page:
all pages
SFR Address: 0xA1
R
R/W
R/W
R/W
R
R
R
R
Reset Value
SPIBSY
MSTEN
CKPHA
CKPOL
SLVSEL
NSSIN
SRMT
RXBMT
00000111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
SPIBSY: SPI Busy (read only).
This bit is set to logic ‘1’ when a SPI transfer is in progress (Master or slave Mode).
MSTEN: Master Mode Enable.
0: Disable master mode. Operate in slave mode.
1: Enable master mode. Operate as a master.
CKPHA: SPI0 Clock Phase.
This bit controls the SPI0 clock phase.
0: Data centered on first edge of SCK period.*
1: Data centered on second edge of SCK period.*
CKPOL: SPI0 Clock Polarity.
This bit controls the SPI0 clock polarity.
0: SCK line low in idle state.
1: SCK line high in idle state.
SLVSEL: Slave Selected Flag (read only).
This bit is set to logic ‘1’ whenever the NSS pin is low indicating SPI0 is the selected slave. It
is cleared to logic ‘0’ when NSS is high (slave not selected). This bit does not indicate the
instantaneous value at the NSS pin, but rather a de-glitched version of the pin input.
NSSIN: NSS Instantaneous Pin Input (read only).
This bit mimics the instantaneous value that is present on the NSS port pin at the time that
the register is read. This input is not de-glitched.
SRMT: Shift Register Empty (Valid in Slave Mode, read only).
This bit will be set to logic ‘1’ when all data has been transferred in/out of the shift register,
and there is no new information available to read from the transmit buffer or write to the
receive buffer. It returns to logic ‘0’ when a data byte is transferred to the shift register from
the transmit buffer or by a transition on SCK.
NOTE: SRMT = 1 when in Master Mode.
RXBMT: Receive Buffer Empty (Valid in Slave Mode, read only).
This bit will be set to logic ‘1’ when the receive buffer has been read and contains no new
information. If there is new information available in the receive buffer that has not been read,
this bit will return to logic ‘0’.
NOTE: RXBMT = 1 when in Master Mode.
*Note: In slave mode, data on MOSI is sampled in the center of each data bit. In master mode, data on MISO is
sampled one SYSCLK before the end of each data bit, to provide maximum settling time for the slave
device. See Table 20.1 for timing parameters.
242
Rev. 1.2
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 20.2. SPI0CN: SPI0 Control
SFR Page:
all pages
SFR Address: 0xF8
(bit addressable)
R/W
R/W
R/W
SPIF
WCOL
MODF
Bit7
Bit6
Bit5
R/W
R/W
R/W
RXOVRN NSSMD1 NSSMD0
Bit4
Bit3
Bit2
R
R/W
Reset Value
TXBMT
SPIEN
00000110
Bit1
Bit0
Bit 7:
SPIF: SPI0 Interrupt Flag.
This bit is set to logic ‘1’ by hardware at the end of a data transfer. If interrupts are enabled,
setting this bit causes the CPU to vector to the SPI0 interrupt service routine. This bit is not
automatically cleared by hardware. It must be cleared by software.
Bit 6:
WCOL: Write Collision Flag.
This bit is set to logic ‘1’ by hardware (and generates a SPI0 interrupt) to indicate a write to
the SPI0 data register was attempted while a data transfer was in progress. It must be
cleared by software.
Bit 5:
MODF: Mode Fault Flag.
This bit is set to logic ‘1’ by hardware (and generates a SPI0 interrupt) when a master mode
collision is detected (NSS is low, MSTEN = 1, and NSSMD[1:0] = 01). This bit is not automatically cleared by hardware. It must be cleared by software.
Bit 4:
RXOVRN: Receive Overrun Flag (Slave Mode only).
This bit is set to logic ‘1’ by hardware (and generates a SPI0 interrupt) when the receive buffer still holds unread data from a previous transfer and the last bit of the current transfer is
shifted into the SPI0 shift register. This bit is not automatically cleared by hardware. It must
be cleared by software.
Bits 3–2: NSSMD1–NSSMD0: Slave Select Mode.
Selects between the following NSS operation modes:
(See Section 20.2 and Section 20.3).
00: 3-Wire Slave or 3-wire Master Mode. NSS signal is not routed to a port pin.
01: 4-Wire Slave or Multi-Master Mode (Default). NSS is always an input to the device.
1x: 4-Wire Single-Master Mode. NSS signal is mapped as an output from the device and will
assume the value of NSSMD0.
Bit 1:
TXBMT: Transmit Buffer Empty.
This bit will be set to logic ‘0’ when new data has been written to the transmit buffer. When
data in the transmit buffer is transferred to the SPI shift register, this bit will be set to logic ‘1’,
indicating that it is safe to write a new byte to the transmit buffer.
Bit 0:
SPIEN: SPI0 Enable.
This bit enables/disables the SPI.
0: SPI disabled.
1: SPI enabled.
Rev. 1.2
243
C8051F360/1/2/3/4/5/6/7/8/9
SFR Definition 20.3. SPI0CKR: SPI0 Clock Rate
SFR Page:
all pages
SFR Address: 0xA2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
SCR7
SCR6
SCR5
SCR4
SCR3
SCR2
SCR1
SCR0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits 7–0: SCR7–SCR0: SPI0 Clock Rate.
These bits determine the frequency of the SCK output when the SPI0 module is configured
for master mode operation. The SCK clock frequency is a divided version of the system
clock, and is given in the following equation, where SYSCLK is the system clock frequency
and SPI0CKR is the 8-bit value held in the SPI0CKR register.
SYSCLK
f SCK = ------------------------------------------------2 SPI0CKR + 1
for 0
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