C509-L
8-Bit CMOS Microcontroller
User's Manual 10.97
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C509-L Data Sheet Revision History : Previous Releases : Page (new version) 1-6 1-11 3-1 3-12
10.97 06.96 (Original Version)
Page (prev. Subjects (changes since last revision) version) 1-6 1-11 3-1 3-12 Duty cycle for XTAL2 corrected RESET : correction in text “for the duration of two machine cycles“ Correction in text : XRAM is internal 1st paragraph: sentence “Bit Swap is ...” added; Table 3-2: Text in right column corrected Figure 3-7; corrected and improved Last paragraph og 4.4.2 : last sentence deleted Correction in figure 6-4 and text : “Delay = 1 state“ Correction in text 2nd paragraph : “consists of three ...“ Abbreviations below table 6-10 added Name of bit T1P2 corrected to T2P0 Formula for mode 1,3 baud rate corrected; last sentence added Formula for mode A,B baud rate corrected Several references in the text corrected from IRCON to IRCON0 Description of ICR and ICS added VIL2 modified Improved and extended ICC specification VCC min. changed from 5V - 15% to 5V - 5%
4-12 6-6 6-28 6-78 6-85 6-88 6-93 7-13 7-16 11-1 11-3, 11-4 11-1, 11-5, 11-7 11-7 to11-9
4-12 6-6 6-28 6-78 6-85 6-88 6-93 7-13 7-16 11-1 11-3 11-1, 11-5, 11-7 11-6 to11-8 AC characteristics : 16 MHz clock oscillator duty cycle (DC) for external clock changed to 0.45 to 0.55 Chapter 12 Chapter 12 Improved index; bold page numbers for main definition reference
Edition 10.97 Published by Siemens AG, Bereich Halbleiter, MarketingKommunikation, Balanstraße 73, 81541 München © Siemens AG 1997 All Rights Reserved. Attention please! As far as patents or other rights of third parties are concerned, liability is only assumed for components, not for applications, processes and circuits implemented within components or assemblies. The information describes the type of component and shall not be considered as assured characteristics. Terms of delivery and rights to change design reserved. For questions on technology, delivery and prices please contact the Semiconductor Group Offices in Germany or the Siemens Companies and Representatives worldwide (see address list). Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Siemens Office, Semiconductor Group. Siemens AG is an approved CECC manufacturer. Packing Please use the recycling operators known to you. We can also help you – get in touch with your nearest sales office. By agreement we will take packing material back, if it is sorted. You must bear the costs of transport. For packing material that is returned to us unsorted or which we are not obliged to accept, we shall have to invoice you for any costs incurred. Components used in life-support devices or systems must be expressly authorized for such purpose! Critical components1 of the Semiconductor Group of Siemens AG, may only be used in life-support devices or systems2 with the express written approval of the Semiconductor Group of Siemens AG. 1 A critical component is a component used in a life-support device or system whose failure can reasonably be expected to cause the failure of that life-support device or system, or to affect its safety or effectiveness of that device or system. 2 Life support devices or systems are intended (a) to be implanted in the human body, or (b) to support and/or maintain and sustain human life. If they fail, it is reasonable to assume that the health of the user may be endangered.
General Information C509-L
Table of Contents 1 1.1 1.2 2 2.1 2.2 3 3.1 3.2 3.3 3.4 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 3.4.6 3.4.7 3.4.7.1 3.4.7.2 3.4.7.3 3.4.8 3.5 4 4.1 4.1.1 4.1.2 4.1.3 4.1.4 4.1.5 4.1.6 4.2 4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.4 4.4.1 4.4.2 4.4.3 4.4.4 4.4.5
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 Pin Definitions and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5 Fundamental Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 CPU Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 Memory Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 Program Memory, “Code Space” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Data Memory, “Data Space” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 General Purpose Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Program and Data Memory Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 Interface of External FLASH/ROM/EPROM and External SRAM Memory. . . . . . . . 3-4 Normal Mode Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5 XRAM Mode Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6 Bootstrap Mode Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7 Programming Mode Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8 Special Function Register SYSCON1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10 Operating Mode (Chipmode) Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12 Special Software Unlock Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13 Control Signals of the Chipmodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14 Switching of the SWAP-Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15 Watchdog Timer - Behaviour in the Different Operating Modes . . . . . . . . . . . . . . . 3-16 Special Function Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17 External Bus Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Accessing External Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Role of P0 and P2 as Data/Address Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 External Program Memory Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 PSEN, Program Store Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Overlapping External Data and Program Memory Spaces. . . . . . . . . . . . . . . . . . . . 4-2 ALE, Address Latch Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 Enhanced Hooks Emulation Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 Eight Datapointers for Faster External Bus Access . . . . . . . . . . . . . . . . . . . . . . . . . 4-6 The Importance of Additional Datapointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6 How the Eight Datapointers of the C509-L are Realized . . . . . . . . . . . . . . . . . . . . . 4-6 Advantages of Multiple Datapointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7 Application Example and Performance Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7 XRAM Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 XRAM Access Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 Accesses to XRAM using the DPTR (16-bit Addressing Mode) . . . . . . . . . . . . . . . 4-12 Accesses to XRAM using the Registers R0/R1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12 Reset Operation of the XRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16 Behaviour of Port0 and Port2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Semiconductor Group
1-1
1997-10-01
General Information C509-L
Table of Contents 5 5.1 5.2 5.3 5.4 5.5 5.6 6 6.1 6.1.1 6.1.1.1 6.1.1.2 6.1.1.2.1 6.1.1.2.2 6.1.1.2.3 6.1.1.3 6.1.1.3.1 6.1.1.3.2 6.1.1.3.3 6.1.2 6.1.3 6.1.3.1 6.1.3.2 6.1.3.3 6.2 6.2.1 6.2.2 6.2.3 6.2.4 6.2.5 6.3 6.3.1 6.3.1.1 6.3.1.2 6.3.1.2.1 6.3.1.2.2 6.3.1.2.3 6.3.2 6.3.2.1 6.3.2.2 6.3.3 6.3.3.1 6.3.3.2 6.3.3.3 6.3.4
Page 5-1 5-1 5-3 5-4 5-6 5-6 5-8
Reset and System Clock Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reset Function and Circuitries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hardware Reset Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fast Internal Reset after Power-On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reset Output Pin (RO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oscillator and Clock Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . System Clock Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On-Chip Peripheral Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 Parallel I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 Port Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 Port Structure Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 Quasi-Bidirectional Port Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 Basic Port Circuitry of Port 1 to 6 and 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 Port 0 Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8 Port 0 and Port 2 used as Address/Data Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9 Bidirectional (CMOS) Port Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11 Hardware Power Down Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13 Alternate Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14 Port Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16 Port Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16 Port Loading and Interfacing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 Read-Modify-Write Feature of Ports 1 to 6 and 9 . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 Timer/Counter 0 and 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19 Timer/Counter 0 / 1 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20 Mode 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 Mode 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25 Mode 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26 Mode 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27 The Compare/Capture Unit (CCU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-28 Timer 2 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-33 Timer 2 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-33 Timer 2 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36 Gated Timer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37 Event Counter Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37 Reload of Timer 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37 Operation of the Compare Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39 Compare Timer and Compare Timer 1 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . 6-39 Operating Modes of the Compare Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-42 Compare Functions of the CCU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44 Compare Mode 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-45 Compare Mode 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-47 Compare Mode 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-48 Timer- and Compare-Register Configurations of the CCU . . . . . . . . . . . . . . . . . . . 6-49
Semiconductor Group
1-2
1997-10-01
General Information C509-L
Table of Contents 6.3.4.1 6.3.4.2 6.3.4.3 6.3.4.4 6.3.4.4.1 6.3.4.4.2 6.3.4.5 6.3.4.6 6.3.4.6.1 6.3.4.6.2 6.3.5 6.3.6 6.3.6.1 6.3.6.2 6.3.6.3 6.4 6.4.1 6.4.2 6.4.3 6.4.4 6.4.5 6.4.6 6.5 6.5.1 6.5.1.1 6.5.1.2 6.5.1.3 6.5.2 6.5.2.1 6.5.2.2 6.5.2.3 6.5.3 6.5.3.1 6.5.3.2 6.5.3.3 6.5.3.4 6.6 6.6.1 6.6.2 6.6.3 6.6.4 6.6.5 6.6.6
Page
Timer 2 - Compare Function with Registers CRC, CC1 to CC3 . . . . . . . . . . . . . . . 6-50 Timer 2 - Capture Function with Registers CRC, CC1 to CC4 . . . . . . . . . . . . . . . . 6-53 Compare Function of Register CC4; “Concurrent Compare” . . . . . . . . . . . . . . . . . 6-55 Compare Function of Registers CM0 to CM7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-59 CMx Registers Assigned to the Compare Timer . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60 CMx Registers Assigned to the Timer 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-63 Timer 2 Operating in Compare Mode 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-64 Compare / Capture Operation with Compare Timer 1 . . . . . . . . . . . . . . . . . . . . . . 6-65 Compare Function of Registers CC10 to CC17 . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-66 Capture Function of Registers CC10 to CC17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-68 Modulation Range in Compare Mode 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-69 Using Interrupts in Combination with the Compare Function . . . . . . . . . . . . . . . . . 6-71 Some advantages in using compare interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-71 Interrupt Enable Bits of the Compare/Capture Unit . . . . . . . . . . . . . . . . . . . . . . . . 6-73 Interrupt Flags of the Compare/Capture Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-74 Arithmetic Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-75 MDU Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-75 Operation of the MDU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-77 Multiplication/Division . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-78 Normalize and Shift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-79 The Overflow Flag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-80 The Error Flag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-80 Serial Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-82 Serial Interface 0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-82 Operating Modes of Serial Interface 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-82 Multiprocessor Communication Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-83 Baud Rates of Serial Channel 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-85 Serial Interface 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-90 Operating Modes of Serial Interface 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-90 Multiprocessor Communication Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-92 Baud Rates of Serial Channel 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-92 Detailed Description of the Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-94 Mode 0, Synchronous Mode (Serial Interface 0) . . . . . . . . . . . . . . . . . . . . . . . . . . 6-94 Mode 1/Mode B, 8-Bit UART (Serial Interfaces 0 and 1) . . . . . . . . . . . . . . . . . . . . 6-97 Mode 2, 9-Bit UART (Serial Interface 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-100 Mode 3 / Mode A, 9-Bit UART (Serial Interfaces 0 and 1) . . . . . . . . . . . . . . . . . . 6-100 A/D Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-104 A/D Converter Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-104 A/D Converter Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-107 A/D Converter Clock Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-111 A/D Conversion Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-112 Adjustment of the Sample Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-116 A/D Converter Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-118
Semiconductor Group
1-3
1997-10-01
General Information C509-L
Table of Contents 7 7.1 7.2 7.2.1 7.2.2 7.2.3 7.3 7.4 7.5 7.6 8 8.1 8.1.1 8.1.2 8.1.3 8.1.3.1 8.1.3.2 8.1.4 8.1.5 8.2 9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 10 10.1 10.2 10.2.1 10.2.2 10.3 10.3.1 10.3.2 10.4 10.4.1 10.4.1.1 10.4.1.2 10.4.2 10.4.2.1 10.4.2.2 10.4.2.3
Page
Interrupt System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 Structure of the Interrupt System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 Interrupt Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6 Interrupt Enable Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6 Interrupt Priority Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10 Interrupt Request Flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11 Interrupt Priority Level Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17 How Interrupts are Handled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-19 External Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21 Interrupt Response Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-22 Fail Save Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Programmable Watchdog Timer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Input Clock Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Control Flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Starting the Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The First Possibility of Starting the Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . The Second Possibility of Starting the Watchdog Timer. . . . . . . . . . . . . . . . . . . . . . Refreshing the Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Reset and Watchdog Status Flag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oscillator Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1 8-1 8-2 8-3 8-4 8-4 8-4 8-5 8-5 8-6
Power Saving Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 Hardware Enable for the Use of the Power Saving Modes . . . . . . . . . . . . . . . . . . . 9-2 Power Saving Mode Control Register PCON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3 Idle Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4 Software Power Down Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6 Slow Down Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7 Hardware Power Down Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8 Hardware Power Down Mode Reset Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-10 The Bootstrap Loader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1 General Functions of the Bootstrap Loader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1 Phase I: Check for Existing Custom Software in the External FLASH Memory . . 10-3 Custom Software Check by the Info Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Checksum Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7 Phase II: Automatic Serial Synchronization with the Host . . . . . . . . . . . . . . . . . . . 10-8 Automatic Synchronization Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-9 Baud Rates for Correct Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-12 Phase III: Serial Communication with the Host . . . . . . . . . . . . . . . . . . . . . . . . . . 10-13 Block Transfer Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-13 Header Block Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-15 Data and EOT Block Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-16 Operating Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-17 Selection of Operating Mode 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-19 Selection of Operating Mode 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-23 Selection of Operating Mode 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-24
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1997-10-01
General Information C509-L
Table of Contents 10.4.2.4 10.5 11 11.1 11.2 11.3 11.4 12
Page
Selection of Operating Mode 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-27 Description of the Bootstrap Loader Subroutines . . . . . . . . . . . . . . . . . . . . . . . . . 10-29 Device Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A/D Converter Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1 11-1 11-1 11-5 11-7
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1
Semiconductor Group
1-5
1997-10-01
Introduction C509-L
1Introduction The C509-L is a high-end microcontroller in the Siemens SAB-C500 8-bit microcontroller family. lt is based on the well-known industry standard 8051 architecture; a great number of enhancements and new peripheral features extend its capabilities to meet the extensive requirements of new applications. Further, the C509-L is a superset of the Siemens SAB 80C517/80C517A 8-bit microcontroller thus offering an easy upgrade path for SAB 80C517/80C517A users. The high performance of the C509-L microcontroller is achieved by the C500-Core with a maximum operating frequency of 16 MHz internal (and external) CPU clock. While maintaining all the features of the SAB 80C517A, the C509-L is expanded by one I/O port, in its compare/capture capabilities, by A/D converter functions, by additional 1 KByte of on-chip RAM (now 3 KByte XRAM) and by an additional user-selectable CMOS port structure. The C509-L is mounted in a P-MQFP-100-2 package. Figure 1-1 shows the different functional units of the C509-L and figure 1-2 shows the simplified logic symbol of the C509-L.
C509
On-Chip Emulation Support Module
Watchdog Oscillator Watchdog 8-Bit UART HW/SW Power Down Modes Comp. Timer 1 Port 9
RAM 256 x 8 T0 T2 T1
Boot ROM 512 x 8 CPU C500-Core (8-Dataptr) Port 4 Port 4 I/O I/O I/O I/O I/O
XRAM 3Kx8
MDU
10-Bit ADC
CCU
Port 4 Comp. Timer 1 Port 4 Port 5 Port 4
8-Bit USART
Port 8
Port 7
Port 6
I/O
analog/ analog/ digit. digit. input input
I/O
I/O
I/O
Improved functionality in comparison to the SAB 80C517A.
MCB02493
Figure 1-1 C509-L Functional Units
Semiconductor Group
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1997-10-01
Introduction C509-L
Listed below is a summary of the main features of the C509-L: l l l l l l l l l l l l l l l l Full upward compatibility with SAB 80C517/80C517A 256 byte on-chip RAM 3K byte of on-chip XRAM 256 directly addressable bits 375 ns instruction cycle at 16-MHz oscillator frequency 64 of 111 instructions are executed in one instruction cycle External program and data memory expandable up to 64 Kbyte each On-chip emulation support logic (Enhanced Hooks Technology TM) 10-bit A/D converter – 15 multiplexed inputs – Built-in self calibration Two 16-bit timers/counters (8051 compatible) Three 16-bit timers/counters (can be used in combination with the compare/capture unit) Powerful compare/capture unit (CCU) with up to 29 high-speed or PWM output channels or 13 capture inputs Arithmetic unit for division, multiplication, shift and normalize operations Eight datapointers instead of one for indirect addressing of program and external data memory Extended watchdog facilities – 15-bit programmable watchdog timer – Oscillator watchdog Ten I/O ports – Eight bidirectional 8-bit I/O ports with selectable port structure quasi-bidirectional port structure (8051 compatible) bidirectional port structure with CMOS voltage levels – One 8-bit and one 7-bit input port for analog and digital input signals Two full-duplex serial interfaces with own baud rate generators Four priority level interrupt systems, 19 interrupt vectors Three power saving modes – Slow-down mode – Idle mode – Power-down mode Siemens high-performance ACMOS technology M-QFP-100 rectangular quad flat package Temperature Ranges : SAB-C509-L TA = 0 to 70 °C SAF-C509-L TA = -40 to 85 °C
l l l
l l l
Semiconductor Group
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1997-10-01
Introduction C509-L
Figure 1-2 C509-L Logic Symbol
Semiconductor Group
1-3
1997-10-01
Introduction C509-L
1.1
Pin Configuration
This section describes the pin configuration of the C509-L in the P-MQFP-100-2 package.
Figure 1-3 C509-L Pin Configuration (P-MQFP-100-2, top view)
Semiconductor Group
1-4
1997-10-01
Introduction C509-L
1.2
Pin Definitions and Functions
This section describes all external signals of the C509-L with its function. Table 1-1 Pin Definitions and Functions Symbol P1.0 - P1.7 Pin Number 9-6, 1, 100-98 I/O*) I/O Function Port 1 is an 8-bit bidirectional I/O port with internal pullup resistors. Port 1 pins that have 1's written to them are pulled high by the internal pullup resistors, and in that state can be used as inputs. As inputs, port 1 pins being externally pulled low will source current (I IL, in the DC characteristics) because of the internal pullup resistors. Port 1 can also be switched into a bidirectional mode, in which CMOS levels are provided. In this bidirectional mode, each port 1 pin can be programmed individually as input or output. Port 1 also contains the interrupt, timer, clock, capture and compare pins that are used by various options. The output latch corresponding to a secondary function must be programmed to a one (1) for that function to operate (except when used for the compare functions). The secondary functions are assigned to the pins of port 1 as follows : P1.0 INT3 CC0 Interrupt 3 input / compare 0 output / capture 0 input P1.1 INT4 CC1 Interrupt 4 input / compare 1 output / capture 1 input P1.2 INT5 CC2 Interrupt 5 input / compare 2 output / capture 2 input P1.3 INT6 CC3 Interrupt 6 input / compare 3 output / capture 3 input P1.4 INT2 CC4 Interrupt 2 input / compare 4 output / capture 4 input P1.5 T2EX Timer 2 external reload trigger input P1.6 CLKOUT System clock output P1.7 T2 Counter 2 input
9 8 7 6 1 100 99 98
*) I = Input O = Output
Semiconductor Group
1-5
1997-10-01
Introduction C509-L
Table 1-1 Pin Definitions and Functions (cont’d) Symbol P9.0 - P9.7 Pin Number 74-77, 5-2 I/O*) I/O Function Port 9 is an 8-bit bidirectional I/O port with internal pullup resistors. Port 9 pins that have 1's written to them are pulled high by the internal pullup resistors, and in that state can be used as inputs. As inputs, port 9 pins being externally pulled low will source current (I IL, in the DC characteristics) because of the internal pullup resistors. Port 9 can also be switched into a bidirectional mode, in which CMOS levels are provided. In this bidirectional mode, each port 1 pin can be programmed individually as input or output. Port 9 also serves alternate compare functions. The output latch corresponding to a secondary function must be programmed to a one (1) for that function to operate. The secondary functions are assigned to the pins of port 9 as follows : P9.0-P9.7 CC10-CC17 Compare/capture channel 0-7 output/input XTAL2 is the input to the inverting oscillator amplifier and input to the internal clock generator circuits. When supplying the C509-L with an external clock source, XTAL2 should be driven, while XTAL1 is left unconnected. A duty cycle of 0.45 to 0.55 of the clock signal is required. Minimum and maximum high and low times as well as rise/fall times specified in the AC characteristics must be observed. XTAL1 Output of the inverting oscillator amplifier. This pin is used for the oscillator operation with crystal or ceramic resonartor
XTAL2
12
–
XTAL1
13
–
*) I = Input O = Output
Semiconductor Group
1-6
1997-10-01
Introduction C509-L
Table 1-1 Pin Definitions and Functions (cont’d) Symbol P2.0 – P2.7 Pin Number 14-21 I/O*) I/O Function Port 2 is a 8-bit I/O port. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @DPTR). In this application it uses strong internal pullup resistors when issuing 1s. During accesses to external data memory that use 8-bit addresses (MOVX @Ri), port 2 issues the contents of the P2 special function register. P2.0 - P2.7 A8 - A15 Address lines 8 - 15 Program Store Enable / Read FLASH The PSEN output is a control signal that enables the external program memory to the bus during external code fetch operations. It is activated every third oscillator period. PSEN is not activated during external data memory accesses caused by MOVX instructions. PSEN is not activated when instructions are executed from the internal Boot ROM or from the XRAM. In external programming mode RDF becomes active when executing external data memory read (MOVX) instructions. Address Latch Enable This output is used for latching the low byte of the address into external memory during normal operation. It is activated every third oscillator period except during an external data memory access caused by MOVX instructions. External Access Enable The status of this pin is latched at the end of a reset. When held at low level, the C509-L fetches all instructions from the external program memory. For the C509-L this pin must be tied low. External Flash-EPROM Program Enable A low level at this pin disables the programming of an external Flash-EPROM. To enable the programming of an external Flash-EPROM, the pin PRGEN must be held at high level and bit PRGEN1 in SFR SYSCON1 has to be set. There is no internal pullup resistor connected to this pin.
PSEN / RDF
22
O
ALE
23
O
EA
24
I
PRGEN
25
I
*) I = Input O = Output
Semiconductor Group
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1997-10-01
Introduction C509-L
Table 1-1 Pin Definitions and Functions (cont’d) Symbol P0.0 – P0.7 Pin Number 26, 27, 30-35 I/O*) I/O Function Port 0 is an 8-bit open-drain bidirectional I/O port. Port 0 pins that have 1s written to them float, and in that state can be used as high-impendance inputs. Port 0 is also the multiplexed low-order address and data bus during accesses to external program or data memory. In this operating mode it uses strong internal pullup resistors when issuing 1 s. P0.0 - P0.7 AD0-AD7 Address/data lines 0 - 7 Hardware Power Down A low level on this pin for the duration of one machine cycle while the oscillator is running resets the C509-L. A low level for a longer period will force the part to power down mode with the pins floating. There is no internal pullup resistor connected to this pin. Port 5 is an 8-bit bidirectional I/O port with internal pullup resistors. Port 5 pins that have 1's written to them are pulled high by the internal pullup resistors, and in that state can be used as inputs. As inputs, port 5 pins being externally pulled low will source current (I IL, in the DC characteristics) because of the internal pullup resistors. Port 5 can also be switched into a bidirectional mode, in which CMOS levels are provided. In this bidirectional mode, each port 5 pin can be programmed individually as input or output. Port 5 also serves as alternate function for “Concurrent Compare” and "Set/Reset compare” functions. The output latch corresponding to a secondary function must be programmed to a one (1) for that function to operate. The secondary functions are assigned to the pins of port 5 as follows : P5.0 - P5.7 CCM0-CCM7 Concurrent Compare or Set/Reset lines 0 - 7
HWPD
36
I
P5.0 - P5.7
44-37
I/O
*) I = Input O = Output
Semiconductor Group
1-8
1997-10-01
Introduction C509-L
Table 1-1 Pin Definitions and Functions (cont’d) Symbol OWE Pin Number 45 I/O*) I Function Oscillator Watchdog Enable A high level on this pin enables the oscillator watchdog. When left unconnected, this pin is pulled high by a weak internal pullup resistor. The logic level at OWE should not be changed during normal operation. When held at low level the oscillator watchdog function is turned off. During hardware power down the pullup resistor is switched off. Port 6 is an 8-bit bidirectional I/O port with internal pullup resistors. Port 6 pins that have 1's written to them are pulled high by the internal pullup resistors, and in that state can be used as inputs. As inputs, port 6 pins being externally pulled low will source current (I IL, in the DC characteristics) because of the internal pullup resistors. Port 6 can also be switched into a bidirectional mode, in which CMOS levels are provided. In this bidirectional mode, each port 6 pin can be programmed individually as input or output. Port 6 also contains the external A/D converter control pin, the receive and transmission lines for the serial port 1, and the write-FLASH control signal. The output latch corresponding to a secondary function must be programmed to a one (1) for that function to operate. The secondary functions are assigned to the pins of port 6 as follows : P6.0 ADST External A/D converter start pin P6.1 R×D1 Receiver data input of serial interface 1 P6.2 T×D1 Transmitter data output of serial interface 1 P6.3 WRF The WRF (write Flash) signal is active when the programming mode is selected. In this mode WRF becomes active when executing external data memory write (MOVX) instructions.
P6.0 - P6.7
46-50, 54-56
I/O
46 47 48 49
*) I = Input O = Output
Semiconductor Group
1-9
1997-10-01
Introduction C509-L
Table 1-1 Pin Definitions and Functions (cont’d) Symbol P8.0 - P8.6 Pin Number 57-60, 51-53 I/O*) I Function Port 8 is a 7-bit unidirectional input port. Port pins can be used for digital input if voltage levels meet the specified input high/low voltages, and for the higher 7-bit of the multiplexed analog inputs of the A/D converter simultaneously. P8.0 - P8.6 AIN8 - AIN14 Analog input 8 - 14 Reset Output This pin outputs the internally synchronized reset request signal. This signal may be generated by an external hardware reset, a watchdog timer reset or an oscillator watchdog reset. The RO output is active low. Port 4 is an 8-bit bidirectional I/O port with internal pull-up resistors. Port 4 pins that have 1’s written to them are pulled high by the internal pull-up resistors, and in that state can be used as inputs. As inputs, port 4 pins being externally pulled low will source current (I IL, in the DC characteristics) because of the internal pull-up resistors. Port 4 also erves as alternate compare functions. The output latch corresponding to a secondary functionmust be programmed to a one (1) for that function to operate. The secondary functions are assigned to the pins of port 4 as follows : P4.0 - P4.7 CM0 - CM7 Compare channel 0 - 7 Power Saving Modes Enable / Start Watchdog Timer A low level on this pin allows the software to enter the power down mode, idle and slow down mode. If the low level is also seen during reset, the watchdog timer function is off on default. Usage of the software controlled power saving modes is blocked, when this pin is held on high level. A high level during reset performs an automatic start of the watchdog timer immediately after reset. When left unconnected this pin is pulled high by a weak internal pullup resistor. During hardware power down the pullup resistor is switched off.
RO
61
O
P4.0 – P4.7
64-66, 68-72
I/O
PE / SWD
67
I
*) I = Input O = Output
Semiconductor Group
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1997-10-01
Introduction C509-L
Table 1-1 Pin Definitions and Functions (cont’d) Symbol RESET Pin Number 73 I/O*) I Function RESET A low level on this pin for the duration of two machine cycles while the oscillator is running resets the C509-L. A small internal pullup resistor permits power-on reset using only a capacitor connected to VSS. Reference voltage for the A/D converter Reference ground for the A/D converter Port 7 Port 7 is an 8-bit unidirectional input port. Port pins can be used for digital input if voltage levels meet the specified input high/low voltages, and for the lower 8-bit of the multiplexed analog inputs of the A/D converter simultaneously. P7.0 - P7.7 AIN0 - AIN7 Analog input 0 - 7
VAREF VAGND
P7.0 - P7.7
78 79 87-80
– – I
*) I = Input O = Output
Semiconductor Group
1-11
1997-10-01
Introduction C509-L
Table 1-1 Pin Definitions and Functions (cont’d) Symbol P3.0 – P3.7 Pin Number 90-97 I/O*) I/O Function Port 3 is an 8-bit bidirectional I/O port with internal pullup resistors. Port 3 pins that have 1's written to them are pulled high by the internal pullup resistors, and in that state can be used as inputs. As inputs, port 3 pins being externally pulled low will source current (I IL, in the DC characteristics) because of the internal pullup resistors. Port 3 also contains two external interrupt inputs, the timer 0/1 inputs, the serial port 0 receive/transmit line and the external memory strobe pins. The output latch corresponding to a secondary function must be programmed to a one (1) for that function to operate. The secondary functions are assigned to the port pins of port 3 as follows P3.0 R×D0 Receiver data input (asynchronous) or data input/output (synchronous) of serial interface 0 P3.1 T×D0 Transmitter data output (asynchronous) or clock output (synchronous) of the serial interface 0 P3.2 INT0 Interrupt 0 input / timer 0 gate control P3.3 INT1 Interrupt 1 input / timer 1 gate control P3.4 T0 Counter 0 input P3.5 T1 Counter 1 input The write control signal latches the data P3.6 WR byte from port 0 into the external data memory P3.7 RD / The read control signal enables the external data memory to port 0 PSENX PSENX (external program store enable) enables the external code memory when the external / internal XRAM mode or external / internal programming mode is selected. Circuit ground potential Supply terminal for all operating modes
90
91
92 93 94 95 96
97
VSS VCC
*) I = Input O = Output
10, 28, 62, 88 11, 29, 63, 89
– –
Semiconductor Group
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1997-10-01
Fundamental Structure C509-L
2
Fundamental Structure
The C509-L is the high-end 8051-compatible microcontroller of the C500 microcontroller family with a significantly increased performance of CPU and peripheral units. It includes the complete SAB 80C517A functionality, providing 100% upward compatibility. This means that all existing 80517A programs or user’s program libraries can be used further on without restriction and may be easily extended to the C509-L. Some of the various on-chip peripherals of the C509-L support the 8-bit core in case of stringent real-time requirements. The 32-bit/16-bit arithmetic unit, the improved 4-level interrupt structure and eight 16-bit datapointers are meant to give such a CPU support. But strict compatibility to the 8051 architecture is a principle of the C509-L design. Furthermore, the C509-L contains eight 8-bit I/O ports and fifteen general input lines. The second serial channel is compatible to the 8051-UART and provided with an independent and freely programmable baud rate generator. An 10-bit resolution A/D-converter with built-in self calibration has been integrated to allow analog signal processing. The C509-L further includes a powerful compare/capture unit with two 16-bit compare timers for all kinds of digital signal processing. The controller has been completed with well considered provisions for “fail-safe” reaction in critical applications and offers all CMOS features like low power consumption as well as an idle, powerdown and slow-down mode. Figure 2-1 shows the block diagram of the C509-L.
Semiconductor Group
2-1
1997-10-01
Fundamental Structure C509-L
Figure 2-1 Block Diagram of the C509-L Semiconductor Group 2-2 1997-10-01
Fundamental Structure C509-L
2.1
CPU
The CPU is designed to operate on bits and bytes. The instructions, which consist of up to 3 bytes, are performed in one, two or four machine cycles. One machine cycle requires six oscillator cycles (this number of oscillator cycles differs from other members of the C500 microcontroller family). The instruction set has extensive facilities for data transfer, logic and arithmetic instructions. The Boolean processor has its own full-featured and bit-based instructions within the instruction set. The C509-L uses five addressing modes: direct access, immediate, register, register indirect access, and for accessing the external data or program memory portions a base register plus index-register indirect addressing.Efficient use of program memory results from an instruction set consisting of 44 % one-byte, 41 % two-byte, and 15 % three-byte instructions. With a 16 MHz clock, 58 % of the instructions execute in 375 ns. The CPU (Central Processing Unit) of the C509-L consists of the instruction decoder, the arithmetic section and the program control section. Each program instruction is decoded by the instruction decoder. This unit generates the internal signals controlling the functions of the individual units within the CPU. They have an effect on the source and destination of data transfers, and control the ALU processing. The arithmetic section of the processor performs extensive data manipulation and is comprised of the arithmetic/logic unit (ALU), an A register, B register and PSW register. The ALU accepts 8-bit data words from one or two sources and generates an 8-bit result under the control of the instruction decoder. The ALU performs the arithmetic operations add, substract, multiply, divide, increment, decrement, BDC-decimal-add-adjust and compare, and the logic operations AND, OR, Exclusive OR, complement and rotate (right, left or swap nibble (left four)). Also included is a Boolean processor performing the bit operations as set, clear, completement, jump-if-not-set, jump-if-set-and-clear and move to/from carry. Between any addressable bit (or its complement) and the carry flag, it can perform the bit operations of logical AND or logical OR with the result returned to the carry flag. The program control section controls the sequence in which the instructions stored in program memory are executed. The 16-bit program counter (PC) holds the address of the next instruction to be executed. The conditional branch logic enables internal and external events to the processor to cause a change in the program execution sequence.
Accumulator A CC is the symbol for the accumulator register. The mnemonics for accumulator-specific instructions, however, refer to the accumulator simply as A. Program Status Word The Program Status Word (PSW) contains several status bits that reflect the current state of the CPU.
Semiconductor Group
2-3
1997-10-01
Fundamental Structure C509-L
Special Function Register PSW (Address D0H) MSB D7H CY
Reset Value : 00H LSB D0H P PSW
Bit No. D0H
D6H AC
D5H F0
D4H RS1
D3H RS0
D2H OV
D1H F1
Bit CY AC F0 RS1 RS0
Function Carry Flag Used by arithmetic instructions. Auxiliary Carry Flag Used by instructions which execute BCD operations) General Purpose Flag Register Bank select control bits These bits are used to select one of the four register banks. RS1 0 0 1 1 RS0 0 1 0 1 Function Bank 0 selected, data address 00H-07H Bank 1 selected, data address 08H-0FH Bank 2 selected, data address 10H-17H Bank 3 selected, data address 18H-1FH
OV F1 P
Overflow Flag General Purpose Flag Used by arithmetic instructions. Parity Flag Set/cleared by hardware after each instruction cycle to indicate an odd/even number of “one” bits in the accumulator, i.e. even parity.
B Register The B register is used by 8-bit multiply and divide instructions and serves as both source and destination. For other instructions it can be treated as another scratch pad register. Stack Pointer The stack pointer (SP) register is 8 bits wide. It is incremented before data is stored during PUSH and CALL executions and decremented after data is popped during a POP and RET (RETI) execution, i.e. it always points to the last valid stack byte. While the stack may reside anywhere in the on-chip RAM, the stack pointer is initialized to 07H after a reset. This causes the stack to begin a location = 08H above register bank zero. The SP can be read or written under software control.
Semiconductor Group
2-4
1997-10-01
Fundamental Structure C509-L
2.2
CPU Timing
A machine cycle consists of 6 states (6 oscillator periods). Each state is divided into a phase 1 half, during OSC is high, and a phase 2 half, during which OSC is low. Thus, a machine cycle consists of 6 oscillator periods, numbered S1P1 (state 1, phase 1) through S6P2 (state 6, phase 2). Each state lasts for one oscillator period. Typically, arithmetic and logical operations take place during phase 1 and internal register-to-register transfers take place during phase 2. The diagrams in figure 2-2 show the fetch/execute timing related to the internal states and phases. Since these internal clock signals are not user-accessible, the XTAL1 oscillator signals and the ALE (address latch enable) signal are shown for external reference. ALE is normally activated twice during each machine cycle: once during S1P2 and S2P1, and again during S4P2 and S5P1. Executing of a one-cycle instruction begins at S1P2, when the op-code is latched into the instruction register. If it is a two-byte instruction, the second reading takes place during S4 of the same machine cycle. If it is a one-byte instruction, there is still a fetch at S4, but the byte read (which would be the next op-code) is ignored (discarded fetch), and the program counter is not incremented. In any case, execution is completed at the end of S6P2. Figures 2-2 a) and b) show the timing of a 1-byte, 1-cycle instruction and for a 2-byte, 1-cycle instruction. Most C509-L instructions are executed in one cycle. MUL (multiply) and DIV (divide) are the only instructions that take more than two cycles to complete; they take four cycles. Normally two code bytes are fetched from the program memory during every machine cycle. The only exception to this is when a MOVX instruction is executed. MOVX is a one-byte, 2-cycle instruction that accesses external data memory. During a MOVX, the two fetches in the second cycle are skipped while the external data memory is being addressed and strobed. Figure 2-2 c) and d) show the timing for a normal 1-byte, 2-cycle instruction and for a MOVX instruction.
Semiconductor Group
2-5
1997-10-01
Fundamental Structure C509-L
Figure 2-2 Fetch and Execute Sequences
Semiconductor Group
2-6
1997-10-01
Memory Organization C509-L
3
Memory Organization
The C509-L CPU manipulates data and operands in the following five address spaces: – – – – – – up to 64 Kbyte of external program memory up to 64 Kbyte of external data memory 512 byte of internal Boot ROM (program memory) 256 bytes of internal data memory 3 Kbyte of internal XRAM data memory a 128 byte special function register area
Figure 3-1 illustrates the memory address spaces of the C509-L.
Figure 3-1 C509-L Memory Map The internal XRAM data memory overlaps with the external data memory in the address range from F400H to FFFFH. In this address range, either external or internal data RAM can be used. If the internal XRAM has been enabled, it only can be disabled by an active RESET or HWPD signal. The internal Boot ROM also overlaps with the external code memory in the address range from 0000H to 01FFH. Depending on the selected operating mode (chipmode), either external code memory or the internal Boot ROM is accessed in this address range.
Semiconductor Group
3-1
1997-10-01
Memory Organization C509-L
3.1
Program Memory, “Code Space”
Besides the internal Boot ROM, the C509-L has no internal program memory (ROM). In normal mode the program memory of the C509-L is located externally and can be expanded up to 64 Kbyte. In the normal mode the C509-L fetches all instructions from the external program memory. Therefore, the pin EA of the C509-L must be always tied to low level. The Boot ROM includes a bootstrap loader program for the bootstrap mode of the C509-L. The software routines of the bootstrap loader program allow the easy and quick programming or loading of the internal XRAM (F400H to FFFFH) via the serial interface while the MCU is in-circuit. This allows to transfer custom routines to the XRAM, which will program an external 64 KByte FLASH memory. The routines of the bootstrap loader program may be executed or even can be blocked to prevent unauthorized persons from reading out or writing to the external FLASH memory. Therefore, the bootstrap loader checks an external FLASH memory for existing custom software and executes it. The bootstrap loader program is described in detail in chapter 10. 3.2 Data Memory, “Data Space”
The data memory address space consists of an internal and an external memory space. The internal data memory is divided into three physically separate and distinct blocks: the lower 128 bytes of RAM, the upper 128 bytes of RAM, and the 128 byte special function register (SFR) area. While the upper 128 bytes of data memory and the SFR area share the same address locations, they are accessed through different addressing modes. The lower 128 bytes of data memory can be accessed through direct or register indirect addressing; the upper 128 bytes of RAM can be accessed through register indirect addressing; the special function registers are accessible through direct addressing. Four 8-register banks, each bank consisting of eight 8-bit multi-purpose registers, occupy locations 0 through 1FH in the lower RAM area. The next 16 bytes, locations 20H through 2FH, contain 128 directly addressable bit locations. The stack can be located anywhere in the internal data memory address space, and the stack depth can be expanded up to 256 bytes. The external data memory can be expanded up to 64 Kbytes and can be accessed by instructions that use a 16-bit or an 8-bit address. The internal XRAM is also located in the external data memory area and must be accessed by external data memory instructions (MOVX). The XRAM can also serve as code memory in the XRAM mode and in the FLASH programming mode. In these modes program code which has been prior loaded via the bootstrap loader program, is executed in the XRAM. 3.3 General Purpose Registers
The lower 32 locations of the internal RAM are assigned to four banks with eight general purpose registers (GPRs) each. 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 chapter 2). This allows fast context switching, which is useful when entering subroutines or interrupt service routines. The 8 general purpose registers of the selected register bank may be accessed by register addressing. With register addressing the instruction op code indicates which register is to be used. For indirect addressing R0 and R1 are used as pointer or index register to address internal or external memory (e.g. MOV @R0).
Semiconductor Group
3-2
1997-10-01
Memory Organization C509-L
Reset initializes the stack pointer to location 07H and increments it once to start from location 08H which is also the first register (R0) of register bank 1. Thus, if one is going to use more than one register bank, the SP should be initialized to a different location of the RAM which is not used for data storage. 3.4 Program and Data Memory Organization
The C509-L can operate in four different operating modes (chipmodes) with different program and data memory organizations: – – – – Normal Mode XRAM Mode Bootstrap Mode Programming Mode
Table 3-1 describes the program and data memory areas which are available in the different chipmodes of the C509-L. It also shows the control bits of SFR SYSCON1, which are used for the software selection of the chipmodes. Table 3-1 Overview of Program and Data Memory Organization Operating Mode (Chipmode) Normal Mode Program Memory Ext. 0000H FFFFH 0200H F3FFH Int.
–
Data Memory Ext. 0000H F3FFH 0000H FFFFH (read only) Int. F400H FFFFH (XRAM)
–
SYSCON1 Bits PRGEN 1 0 SWAP 0
XRAM Mode
0000H 01FFH = Boot ROM; F400H FFFFH = (XRAM) 0000H 01FFH = Boot ROM 0000H 01FFH = Boot ROM; F400H FFFFH = XRAM
0
1
Bootstrap Mode
0200H F3FFH 0200H FFFFH
0000H F3FFH 0000H FFFFH (read and write)
F400H FFFFH (XRAM)
–
1
0
Programming Mode
1
1
Semiconductor Group
3-3
1997-10-01
Memory Organization C509-L
3.4.1 Interface of External FLASH/ROM/EPROM and External SRAM Memory The external FLASH/ROM/EPROM memory and the external SRAM memory can be used in the chipmodes either as code memory or as data memory. The basic memory configuration is shown in figure 3-2. The following alternate function pins control the read/write accesses for code/data memories: PSEN / RDF P6.3 / WRF P3.6 / WR P3.7 / RD / PSENX Read control signal for the FLASH/ROM/EPROM memory Write control signal for the FLASH/ROM/EPROM memory Write control signal for the SRAM memory Read control signal for the SRAM memory
Figure 3-2 Interface of External FLASH/ROM/EPROM and External SRAM Memory
Semiconductor Group
3-4
1997-10-01
Memory Organization C509-L
3.4.2 Normal Mode Configuration The Normal Mode is the standard 8051 compatible operating mode of the C509-L. In this mode 64K byte external code memory and 61K byte external SRAM as well as 3K byte internal data memory (XRAM) are provided. If the XRAM is disabled (default after reset), totally 64K byte external data memory are available. The Boot ROM is disabled. The external program memory is controlled by the PSEN/RDF signal. Read and write accesses to the external data memory are controlled by the RD and WR pins of port 3. The Normal Mode is entered by keeping the pin PRGEN at a logic low during the rising edge of the external RESET or HWPD signal. The locations of the code- and data-memory in Normal Mode are shown in figure 3-4.
Figure 3-3 Locations of Code- and Data Memory in Normal Mode
Semiconductor Group
3-5
1997-10-01
Memory Organization C509-L
3.4.3 XRAM Mode Configuration The XRAM Mode is implemented in the C509-L for executing e.g. up to 3K byte diagnostic software which has been loaded into the XRAM in the Bootstrap Mode via the serial interface. In this operating mode the Boot ROM, the XRAM, and the external data memory are mapped into the code memory area, while the external ROM/EPROM is mapped into the external data memory area. External program memory fetches from the SRAM are controlled by the P3.7/RD/PSENX pin. External data memory read accesses from the ROM/EPROM are controlled by the PSEN/RDF pin. In XRAM mode, the external data memory can only be read but not written. The XRAM mode is entered by setting the SWAP bit, while the PRGEN pin (PRGEN1 bit) is kept low. The locations of the code- and data-memory in the XRAM mode are shown in figure 3-4.
Figure 3-4 Locations of Code- and Data Memory in XRAM Mode
Notes: In the XRAM mode, programming of the external FLASH EPROM is not possible because the PRGEN pin (PRGEN1 bit) is at logic low level (HW-protection). The internal XRAM is selected automatically in the code memory, if the SWAP bit is set. When leaving the XRAM Mode, the XRAM is disabled (only if the XMAP0 bit was not cleared by software before).
Semiconductor Group
3-6
1997-10-01
Memory Organization C509-L
3.4.4 Bootstrap Mode Configuration In the Bootstrap Mode the Boot ROM and the external FLASH/ROM/EPROM are mapped into the code memory area. 61K byte external SRAM as well as 3K byte internal data memory (XRAM) are provided in the external data memory area. The external program memory is controlled by the PSEN/RDF signal. Read and write accesses to the external data memory are controlled by the RD and WR pins of port 3. The Bootstrap Mode is entered by keeping the pin PRGEN at a logic high level during the rising edge of the external RESET or HWPD signal (→ PRGEN1=1). The locations of the code- and data memory in the external boot-strap mode are shown in figure 3-5.
Figure 3-5 Locations of Code- and Data Memory in Bootstrap Mode In Bootstrap Mode the internal XRAM is selected automatically as data memory. When leaving the Bootstrap Mode, the XRAM is disabled (only if the XMAP0 bit was not cleared by software before).
Semiconductor Group
3-7
1997-10-01
Memory Organization C509-L
3.4.5 Programming Mode Configuration The External Programming Mode is implemented for the in-circuit programming of external 5V-only FLASH EPROMs. Similar as in the XRAM mode, the Boot ROM, the XRAM, and the external data memory (SRAM) are mapped into the code memory area, while the external FLASH memory is mapped into the external data memory area. Additionally to the XRAM mode, the FLASH memory can also be written through external data memory accesses (MOVX instructions). External program memory fetches from the SRAM are controlled by the P3.7/RD/PSENX pin. External data memory read/write accesses from/to the ROM/EPROM are controlled by the PSEN/RDF and P6.3/WRF pin. The Programming Mode is entered by setting the bits PRGEN1 and SWAP in SFR SYSCON1. The locations of the code- and data memory in the Programming Mode are shown in figure 3-6.
Figure 3-6 Locations of Code- and Data Memory in Programming Mode Prior to the usage of the Programming Mode, the XRAM has to be loaded by the FLASH specific programming software algorithms (see also chapter 10 “The Bootstrap Loader”). This XRAM load operation can be done using the Bootstrap Mode.
Semiconductor Group
3-8
1997-10-01
Memory Organization C509-L
Notes: The internal XRAM is enabled automatically in the code memory area if the SWAP bit is set. When leaving the Programming Mode, the XRAM is disabled (only if the XMAP0 bit was not cleared by software before). Leaving the Programming Mode can be accomplished by: Clearing the bits PRGEN1 and SWAP prior to executing the special software unlock sequence followed by a LJMP to “startaddress” in the FLASH memory returns the C509-L into normal mode (program execution will start at “startaddress”). – Activating the RESET or HWPD signal with the PRGEN pin at logic low level will clear the bits PRGEN1 and SWAP. Notes: Switching the PRGEN pin to logic low level during programming of an external FLASH will reset the PRGEN1 bit. As a result the XRAM mode is entered and this inhibits any write access to the external FLASH EPROM. Clearing the SWAP bit during Programming Mode and executing the special software unlock sequence will force the C509-L into the Bootstrap Mode. –
Semiconductor Group
3-9
1997-10-01
Memory Organization C509-L
3.4.6 Special Function Register SYSCON1 There are five control bits located in SFR SYSCON1 (B2H) which control the code and data memory organization of the C509-L. Two of these bits (PRGEN1 and SWAP) cannot be programmed as normal bits but with a special software unlock sequence. The special software unlock sequence was implemented to prevent unintentional changing of these bits and consists of consecutive followed instructions which have to set two dedicated enable bits. Special Function Register SYSCON1 (Address B2H) MSB 7 ESWC Reset Value : 00XXXEE0B 1) LSB 0 SYSCON1
Bit No. B2H
6 SWC
5
–
4 EA1
3 EA0
2
1
PRGEN1 PRGEN0 SWAP
1) “E” means that the value of the bit is defined through the external logic level at pin PRGEN at the rising edge of the external RESET or HWPD signals.
Bit ESWC
Function Enable Switch Chipmode When selecting the chipmode with the bits SWAP and PRGEN1, the ESWC bit has to be set simultaneously as the first instruction in the special software unlock sequence. The bit ESWC will be cleared by hardware after 2 instruction cycles. Switch Chip Mode The SWC bit has to be set as the second instruction in a special software unlock sequence directly after having set bit ESWC. The new chipmode becomes active after the second instruction cycle which follows the special software unlock sequence. These two instruction cycles are used for initializing of the program counter (LJMP instruction) SWC is a write only bit. Reading SWC will always return a ‘0’. Reserved bits; at read operations these bits are undefined; at write operations to SYSCON1 these bits can be written with “0” or “1”. Program Enable Bit 1 The PRGEN1 bit enables/disables the write accesses to an external FLASH EPROM. The PRGEN1 bit contains the logic value of the external PRGEN pin which is latched at the rising edge of the external RESET or HWPD signal. When the logic low level appears at the PRGEN pin, the PRGEN1 bit will be cleared in the next instruction cycle without the need of a special software unlock sequence. PRGEN1 = 0: Write access (programming) of external FLASH EPROM is disabled PRGEN1 = 1: Write access (programming) of external FLASH EPROM is enabled Any changing the PRGEN1 bit without using a special software unlock sequence with the ESWC and SWC bits will have no effect and the former selected status will be kept.
SWC
–, EA1, EA0 PRGEN1
Semiconductor Group
3-10
1997-10-01
Memory Organization C509-L
Bit PRGEN0
Function Program Enable Bit 0 The PRGEN0 bit is a read-only bit and represents the logic level of the external PRGEN pin. PRGEN0 = 1: The PRGEN1 bit can be set or cleared under software control. PRGEN0 = 0: The PRGEN1 bit is held at logic low level and cannot be set under software control. Notes: Clearing the PRGEN0 bit by changing the logic level at the PRGEN pin in the Normal Mode disables write accesses to the external FLASH EPROM. Enable/disable write accesses to external FLASH EPROM can be done by changing the PRGEN1 bit with a special software unlock sequence. Swap Code- and Data Memory SWAP = 0: The data memory and the code memory remain in their predefined locations. SWAP = 1: The following address areas and memory locations are assigned to code memory: 0000H - 01FFH → Boot ROM 0200H - F3FFH → External data memory is swapped to external code memory F400H - FFFFH → The XRAM is enabled and automatically mapped into code memory space. (independent of bit XMAP0 in SFR SYSCON) The following address areas and memory locations ar assigned to data memory: 0000H - FFFFH → External FLASH /ROM/EPROM The former code memory is assigned as data memory and is now addressable by using MOVX instructions.
SWAP
Semiconductor Group
3-11
1997-10-01
Memory Organization C509-L
3.4.7 Operating Mode (Chipmode) Selection The chipmode selection can be done by hardware after an active RESET or HWPD signal. Further, the logic state of pin PRGEN is used for hardware selection. Bit Swap is not affected by hardware selection. The chipmodes can also be selected by software. Software selection is achieved by programming specific bits of SFR SYSCON1. The following table 3-2 shows the hardware and software selection capabilities of the chipmodes. Table 3-2 Hardware and Software Selection of Chipmodes Operating Mode (Chipmode) Normal Mode Hardware Selection PRGEN pin = low RESET or HWPD: 1 edge 2 Software Selection PRGEN pin = don’t care; 4 setting bits PRGEN1,SWAP = 0,0; executing unlock sequence PRGEN pin = don’t care; 5 setting bits PRGEN1,SWAP = 0,1; executing unlock sequence
XRAM Mode
from Programming Mode: setting PRGEN pin = low PRGEN pin = high RESET or HWPD: not possible
Bootstrap Mode
3 PRGEN pin = high; 6 edge setting bits PRGEN1,SWAP =1,0; executing unlock sequence PRGEN pin = high; 7 setting bits PRGEN1,SWAP = 1,1; executing unlock sequence
Programming Mode
Figure 3-7 below shows the information of table 3-2 as a state diagram (reference number in the circle).
1 Normal Mode PRGEN1, SWAP = 0,0 4 5 XRAM Mode PRGEN1, SWAP = 0,1 5 2 5 6 Bootstrap Mode PRGEN1, SWAP = 1,0 3 6 7 6 4 7 Programming Mode PRGEN1, SWAP = 1,1 4 7
Hardware Selection Software Selection
MCD02645
Figure 3-7 State Diagram of Chipmode Selection Semiconductor Group 3-12 1997-10-01
Memory Organization C509-L
3.4.7.1
Special Software Unlock Sequence
The bits ESWC and SWC in SFR SYSCON1 are implemented in a way to prevent unintentional changing of the bits SWAP or PRGEN1. Any changing the bits SWAP or PRGEN1 without using the ESWC and SWC bits in a special software unlock sequence will have no effect and the above bits will get back their old values two instruction cycles after being changed. The following programming steps must be executed at the ESWC/SWC unlock sequence: 1.) First instruction: Changing the value of the bits SWAP or PRGEN1 with one or more consecutive instructions simultaneously with setting of bit ESWC: ANL SYSCON1, #11111X1YB ORL SYSCON1, #10000X0YB ; clearing of bits PRGEN1 (X=0) and/or SWAP (Y=0) ; setting of ESWC bit with setting of PRGEN1 or SWAP ; e.g. clearing of the SWAP bit: ANL SYSCON1,#11111110B ORL SYSCON1,#10000000B
or: ORL SYSCON1, #10000X0YB ; setting of the bits PRGEN1 (X=1) and/or SWAP (Y=1) and ; setting the ESWC bit simultaneously ; e.g. setting of the SWAP bit: ORL SYSCON1,#10000001B
2.) Second instruction: Setting of bit SWC immediately after 1.) with ORL SYSCON1, #40H ;
The new chipmode becomes active two instruction cycles after the instruction which sets the bit SWC (see 2.). These two instruction cycle delay should normally be used for initialization of the program counter to the 16 bit start-address of the new code memory resource, e.g. with: LJMP 0XXXXH ; XXXX = 16-bit hex address in new code memory
If the code memory resource is not changed by the new chipmode there is no need of a new initialization of the program counter. However the new Chipmode becomes active two instruction cycles after 2.). The special software unlock instruction sequence cannot be interrupted by an interrupt request. Any write or read operation to SFR SYSCON1 will block the interrupt generation for the first cycle of the directly following instruction.Therefore, the response time of an interrupt request may be additionally delayed from minimal five instruction cycles up to eight instruction cycles: four or six instruction cycles for setting ESWC and SWC (depends on the used instructions) and one or two instruction cycles depending on the instruction used in 3.). When using a one cycle instruction in 3.) an enabled interrupt may be performed and the interrupt vector address may reside in a “new” code memory resource due to the new selected Chipmode. The bits SWAP and PRGEN1 are built up by three shadow latches each. Unintentional changing of one of this three latches (e.g. by RFI) will have no effect and the former value will be restored in the next instruction cycle.
Semiconductor Group
3-13
1997-10-01
Memory Organization C509-L
3.4.7.2
Control Signals of the Chipmodes
As shown in chapter 3.4.2 to 3.4.5, each chipmode uses specific read/write control signals, Table 3-3 gives a detailed survey about each chipmode and its control signals. Table 3-3 Usage of Control Signals in the different Chipmodes Operating Mode (Chipmode) Normal Mode Code Memory Control PSEN / RDF 0000H FFFFH Data Memory Control PSEN / RDF P6.3 / WRF
–
P3.7 / RD / P3.7 / RD / P3.6 / WR PSENX PSENX
–
XMAP0=1 : 0000H FFFFH XMAP0=0 : 0000H F3FFH
–
XMAP0=1 : – 0000H FFFFH XMAP0=0 : 0000H F3FFH
–
XRAM Mode Bootstrap Mode Programming Mode
–
0200H F3FFH
–
0000H FFFFH
–
– –
0200H FFFFH
–
0000H F3FFH
–
0000H F3FFH
–
0200H F3FFH
0000H FFFFH
0000H FFFFH
Semiconductor Group
3-14
1997-10-01
Memory Organization C509-L
3.4.7.3
Switching of the SWAP-Bit
Setting or clearing the SWAP-bit in SYSCON1 will change code memory and data memory assignment. To assure a well defined behavior of the controller, it is necessary to perform a specific code sequence by the user. Any write access to SYSCON1 which changes the SWAP bit has to be followed by a 2-cycle instruction. This 2-cycle instruction will be the last instruction, which is performed by the CPU in the former code memory. For that reason, this 2-cycle instruction has to be a LJMP-instruction which specifies the new address for the program counter. The next instruction, which will be performed by the CPU is at the specified destination address of the JMP instruction in the former data memory (which now has become to code memory). Figure 3-8 gives an overview about the behavior of the external pin PSEN/RDF and RD/PSENX when chipmodes with different SWAP bits are switched. These signals change their functions depending on the value of the SWAP bit.
Figure 3-8 Switching of the SWAP Bit Figure 3-8 a): When the SWAP bit is set, the “program store enable” function of the PSEN/RDF pin, which is connected to OE (output enable) of the FLASH/ROM/EPROM memory, is switched to the RD/PSENX pin. The “read enable” function of the RD/PSENX pin, which is connected to the RD (“read“) input of an external SRAM memory, is switched to the PSEN/RDF signal. PSEN/RDF becomes now active during MOVX instructions. When the SWAP bit is cleared, the “read enable” function (MOVX instructions) of the PSEN/RDF pin, which is connected to OE (output enable) of the FLASH/ROM/EPROM memory, is switched to the RD/PSENX pin. The “program store enable” function of the RD/PSENX pin, which is connected to the RD (“read“) input of the external SRAM memory, is switched to the PSEN/RDF pin. RD/ PSENX becomes now active during MOVX instructions.
Semiconductor Group
3-15
1997-10-01
Memory Organization C509-L
3.4.8 Watchdog Timer - Behaviour in the Different Operating Modes This section describes the chipmode specific behavior of the watchdog timer unit. Further details about the watchdog timer are given in chapter 8. Normal Mode: The watchdog timer function in Normal Mode is not restricted. XRAM Mode: To avoid deadlocks during program execution in the XRAM, the once enabled watchdog timer keeps on running but the refresh is inhibited. A refresh sequence of a previously enabled watchdog timer is not permitted. An unintentional refresh sequence in the XRAM mode does not reload the watchdog timer and an internally generated watchdog reset will be executed at the watchdog counter state 7FFCH. The watchdog timer reset generation is enabled. For refreshing the watchdog timer, the user has to leave the XRAM Mode and must enter the Normal Mode by clearing the SWAP bit followed by a LJMP or LCALL to “startaddress of watchdog timer refresh” in the external ROM/EPROM. In the normal mode the watchdog timer refresh can be executed successfully. If required, XRAM Mode can again be entered after the watchdog timer refresh operation has been finished. Bootstrap Mode and Programming Mode In the Bootstrap Mode and in the Programming Mode the watchdog timer increment is inhibited. In this way, programming the external FLASH EPROM in Programming Mode cannot be aborted by the watchdog timer.
Semiconductor Group
3-16
1997-10-01
Memory Organization C509-L
3.5
Special Function Registers
The registers, except the program counter and the four general purpose register banks, reside in the special function register area. The special function register area consists of two portions: the standard special function register area and two mapped special function register areas. Several special function registers of the C509-L (CC10-17, CT1REL, CC1EN, CAFR) are located in the mapped special function register area. For accessing the mapped special function register area, bit RMAP in special function register SYSCON must be set. All other special function registers are located in the standard special function register area. For accessing the port direction registers, which define the input or output function of the bidirectional port structure, bit PDIR in SFR IP1 is used. This port direction register access operates similar to the mapped SFR accesses, but a double instruction sequence must be executed. The first instruction has to set bit PDIR. Thereafter, the second instruction can read or write the direction register. Further details about port direction selection see chapter 6.1.1.1. The most right column of table 3-5 indicates if an SFR is accessed with a mapped procedure controlled by either RMAP or PDIR. Special Function Register SYSCON (Address B1H) Special Function Register IP1 (Address B9H) Bit No. MSB 7 B1H Reset Value : 1010XX01B Reset Value : 0X000000B LSB 0 SYSCON
6
5 1
4 RMAP
3 –
2 –
1
CLKP PMOD
XMAP1 XMAP0
B9H
PDIR
–
.5
.4
.3
.2
.1
.0
IP1
The functions of the shaded bits are not described in this section. Bit RMAP Function Special function register map bit RMAP = 0: The access to the non-mapped (standard) special function register area is enabled (reset value). RMAP = 1: The access to the mapped special function register area is enabled. Direction register enable PDIR = 0: Port register access is enabled (reset value). PDIR = 1: Direction register is enabled. PDIR will automatically be cleared after the second machine cycle (S2P2) after having been set.
PDIR
Semiconductor Group
3-17
1997-10-01
Memory Organization C509-L
As long as bit RMAP is set, mapped special function registers can be accessed. This bit is not cleared by hardware automatically. Thus, when non-mapped/mapped registers are to be accessed, the bit RMAP must be cleared/set by software, respectively each. There are also 128 directly addressable bits available within each SFR area (standard and mapped SFR area). All SFRs with addresses where address bits 0-2 are 0 (e.g. 80H, 88H, 90H, 98H, …, F8H, FFH) are bitaddressable. The 103 special function register (SFR) include pointers and registers that provide an interface between the CPU and the other on-chip peripherals. The SFRs of the C509-L are listed in table 3-4 and table 3-5. In table 3-4 they are organized in groups which refer to the functional blocks of the C509-L. Table 3-5 illustrates the contents of the SFRs in numeric order of their addresses.
Semiconductor Group
3-18
1997-10-01
Memory Organization C509-L
Table 3-4 Special Function Registers - Functional Blocks Block CPU Symbol ACC B DPH DPL DPSEL PSW SP SYSCON1 Name Accumulator B-Register Data Pointer, High Byte Data Pointer, Low Byte Data Pointer Select Register Program Status Word Stack Pointer System Control Register 1 Address Contents after Reset E0H 1) F0H 1) 83H 82H 92H D0H 1) 81H B2H B1H A8H1) E1H BCH B8H 1) 9AH BEH A9H B9H C0H 1) D1H BFH BFH 88H 1) C8H 1) 91H B1H D8H1) DCH D9H DAH 00H 00H 00H 00H XXXXX000B 3) 00H 07H 00XXXEE0B3)6) 1010XX01B 3) 00H 01000000B 3) X1XX0000B 3) 00H XX0000X0B 3) XXXX00XXB 3) 00H 0X000000B 3) 00H 00H 00H FFH 00H 00H 00H 1010XX01B 3) 00H 01000000B 3) 00H 00H
SFR Mapping Interrupt System
SYSCON 2) System Control Register IEN0 CTCON 2) CT1CON 2) IEN1 2) IEN2 2) IEN3 IP0 2) IP1 2) IRCON0 IRCON1 IRCON2 4) EICC1 4) TCON 2) T2CON 2) Interrupt Enable Register 0 Compare Timer Control Register Compare Timer 1 Control Register Interrupt Enable Register 1 Interrupt Enable Register 2 Interrupt Enable Register 3 Interrupt Priority Register 0 Interrupt Priority Register 1 Interrupt Request Control Register 0 Interrupt Request Control Register 1 Interrupt Request Control Register 2 Interrupt Request Enable Register for CT1 Timer Control Register Timer 2 Control Register
XRAM A/D Converter
XPAGE Page Address Register for XRAM SYSCON 2) System Control Register ADCON0 ADCON1 ADDATH ADDATL A/D Converter Control Register 0 A/D Converter Control Register 1 A/D Converter Data Register, High Byte A/D Converter Data Register, Low Byte
1) 2) 3) 4) 5) 6)
Bit-addressable special function registers This special function register is listed repeatedly since some bits of it also belong to other functional blocks. X means that the value is indeterminate or the location is reserved Register is mapped by bit PDIR. Register is mapped by bit RMAP. “E” means that the value of the bit is defined by the logic level at pin PRGEN at the rising edge of the RESET or HWPD signals.
Semiconductor Group
3-19
1997-10-01
Memory Organization C509-L
Table 3-4 Special Function Registers - Functional Blocks (cont’d) Block Compare / Capture Unit (CCU) Timer 2 Symbol CCEN CC4EN CCH1 CCH2 CCH3 CCH4 CCL1 CCL2 CCL3 CCL4 CMEN 5) CMH0 5) CMH1 5) CMH2 5) CMH3 5) CMH4 5) CMH5 5) CMH6 5) CMH7 5) CML0 5) CML1 5) CML2 5) CML3 5) CML4 5) CML5 5) CML6 5) CML7 5) CC1EN 5) CC1H0 5) CC1H1 5) CC1H2 5) CC1H3 5) CC1H4 5) CC1H5 5) CC1H6 5) CC1H7 5) CC1L0 5) CC1L1 5) CC1L2 5) CC1L3 5) CC1L4 5) CC1L5 5) CC1L6 5) CC1L7 5 CMSEL 5 ) Name Compare/Capture Enable Register Compare/Capture 4 Enable Register Compare/Capture Register 1, High Byte Compare/Capture Register 2, High Byte Compare/Capture Register 3, High Byte Compare/Capture Register 4, High Byte Compare/Capture Register 1, Low Byte Compare/Capture Register 2, Low Byte Compare/Capture Register 3, Low Byte Compare/Capture Register 4, Low Byte Compare Enable Register Compare Register 0, High Byte Compare Register 1, High Byte Compare Register 2, High Byte Compare Register 3, High Byte Compare Register 4, High Byte Compare Register 5, High Byte Compare Register 6, High Byte Compare Register 7, High Byte Compare Register 0, Low Byte Compare Register 1, Low Byte Compare Register 2, Low Byte Compare Register 3, Low Byte Compare Register 4, Low Byte Compare Register 5, Low Byte Compare Register 6, Low Byte Compare Register 7, Low Byte Compare/Capture Enable Register Compare/Capture 1 Register 0, High Byte Compare/Capture 1 Register 1, High Byte Compare/Capture 1 Register 2, High Byte Compare/Capture 1 Register 3, High Byte Compare/Capture 1 Register 4, High Byte Compare/Capture 1 Register 5, High Byte Compare/Capture 1 Register 6, High Byte Compare/Capture 1 Register 7, High Byte Compare/Capture 1 Register 0, Low Byte Compare/Capture 1 Register 1, Low Byte Compare/Capture 1 Register 2, Low Byte Compare/Capture 1 Register 3, Low Byte Compare/Capture 1 Register 4, Low Byte Compare/Capture 1 Register 5, Low Byte Compare/Capture 1 Register 6, Low Byte Compare/Capture 1 Register 7, Low Byte Compare Input Select Address Contents after Reset C1H C9H C3H C5H C7H CFH C2H C4H C6H CEH F6H D3H D5H D7H E3H E5H E7H F3H F5H D2H D4H D6H E2H E4H E6H F2H F4H F6H D3H D5H D7H E3H E5H E7H F3H F5H D2H D4H D6H E2H E4H E6H F2H F4H F7H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H
5)
Register is mapped by bit RMAP.
Semiconductor Group
3-20
1997-10-01
Memory Organization C509-L
Table 3-4 Special Function Registers - Functional Blocks (cont’d) Block Compare / Capture Unit (CCU) Timer 2 cont’d Symbol CAFR 5) CRCH CRCL COMSETL COMSETH COMCLRL COMCLRH SETMSK CLRMSK CTCON 2) CTRELH 5) CTRELL 5)
CT1RELH 5)
Name Capture 1, Falling/Rising Edge Register Comp./Rel./Capt. Reg. High Byte Comp./Rel./Capt. Reg. Low Byte Compare Set Register, Low Byte Compare Set Register, High Byte Compare Clear Register, Low Byte Compare Clear Register, High Byte Compare Set Mask Register Compare Clear Mask Register Compare Timer Control Register Compare Timer Rel. Reg., High Byte Compare Timer Rel. Reg., Low Byte Compare Timer 1 Rel. Reg., High Byte Compare Timer 1 Rel. Reg., Low Byte Timer 2, High Byte Timer 2, Low Byte Timer 2 Control Register Compare Timer 1 Control Register Prescaler Control Register A/D Converter Control Register Power Control Register Serial Channel 0 Buffer Register Serial Channel 0 Control Register Serial Channel 0 Reload Reg., Low Byte Serial Channel 0 Reload Reg., High Byte Serial Channel 1 Buffer Register Serial Channel 1 Control Register Serial Channel 1 Reload Reg., Low Byte Serial Channel 1 Reload Reg., High Byte Interrupt Enable Register 0 Interrupt Enable Register 1 Interrupt Priority Register 0 Interrupt Priority Register 1 Watchdog Timer Reload Register Watchdog Timer Register, Low Byte Watchdog Timer Register, High Byte
Address Contents after Reset F7H CBH CAH A1H A2H A3H A4H A5H A6H E1H DFH DEH DFH DEH CDH CCH C8H 1) BCH B4H D8H 1) 87H 99H 98H 1) AAH BAH 9CH 9BH 9DH BBH A8H 1) B8H 1) A9H B9H 86H 84H 85H 00H 00H 00H 00H 00H 00H 00H 00H 00H 01000000B 3) 00H 00H 00H 00H 00H 00H 00H X1XX0000B 3) 11010101B 3) 00H 00H XXH 3) 00H D9H XXXXXX11B 3) XXH 3) 01000000B 3) 00H XXXXXX11B 3) 00H 00H 00H 0X000000B 3) 00H 00H 00H
CT1RELL 5) TH2 TL2 T2CON 2) CT1CON 2) PRSC 2) Serial Channels ADCON0 2) PCON 2) S0BUF S0CON S0RELL S0RELH S1BUF S1CON S1RELL S1RELH IEN0 2) IEN1 2) IP0 2) IP1 2) WDTREL WDTL 6) WDTH 6)
Watchdog
1) 2) 3) 4) 5) 6)
Bit-addressable special function registers This special function register is listed repeatedly since some bits of it also belong to other functional blocks. X means that the value is indeterminate or the location is reserved Register is mapped by bit PDIR. Register is mapped by bit RMAP. Registers are only readable and cannot be written.
Semiconductor Group
3-21
1997-10-01
Memory Organization C509-L
Table 3-4 Special Function Registers - Functional Blocks (cont’d) Block MUL/DIV Unit Symbol ARCON MD0 MD1 MD2 MD3 MD4 MD5 TCON TH0 TH1 TL0 TL1 TMOD PRSC 2) P0 4) DIR0 4) P1 4) DIR1 4) P2 4) DIR2 4) P3 4) DIR3 4) P4 4) DIR4 4) P5 4) DIR5 4) P6 4) DIR6 4) P7 P8 P9 4) DIR9 4) PCON Name Arithmetic Control Register Multiplication/Division Register 0 Multiplication/Division Register 1 Multiplication/Division Register 2 Multiplication/Division Register 3 Multiplication/Division Register 4 Multiplication/Division Register 5 Timer Control Register Timer 0, High Byte Timer 1, High Byte Timer 0, Low Byte Timer 1, Low Byte Timer Mode Register Prescaler Control Register Port 0 Direction Register Port 0 Port 1 Direction Register Port 1 Port 2 Direction Register Port 2 Port 3 Direction Register Port 3 Port 4 Direction Register Port 4 Port 5 Direction Register Port 5 Port 6 Direction Register Port 6 Port 7, Analog/Digital Input Port 8, Analog/Digital Input Port 9 Direction Register Port 9 Power Control Register Address Contents after Reset EFH E9H EAH EBH ECH EDH EEH 88H 1) 8CH 8DH 8AH 8BH 89H B4H 80H 1) 80H 1) 90H 1) 90H 1) A0H 1) A0H 1) B0H 1) B0H 1) E8H 1) E8H 1) F8H 1) F8H 1) FAH FAH DBH DDH F9H F9H 87H 0XXXXXXXB 3) XXH 3) XXH 3) XXH 3) XXH 3) XXH 3) XXH 3) 00H 00H 00H 00H 00H 00H 11010101B 3) FFH FFH FFH FFH FFH FFH FFH FFH FFH FFH FFH FFH FFH FFH --FFH FFH 00H
Timer 0 / Timer 1
Ports
Power Saving Modes
1) 2) 3) 4) 5)
Bit-addressable special function registers This special function register is listed repeatedly since some bits of it also belong to other functional blocks. X means that the value is indeterminate and the location is reserved Register is mapped by bit PDIR. Register is mapped by bit RMAP.
Semiconductor Group
3-22
1997-10-01
Memory Organization C509-L
Table 3-5 Contents of the SFRs, SFRs in numeric order of their addresses
Addr Register Content Bit 7 after Reset 1) FFH FFH 07H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H FFH FFH 00H XXXX. X000B 00H XXH XX00. 00X0B 0100. 0000B XXH 00H FFH FFH .7 .7 .7 .7 .7 .7 .7
WPSEL
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mapped by 2)
PDIR=0 PDIR=1
80H 80H 81H 82H 83H 84H 85H 86H 87H 88H 89H 8AH 8BH 8CH 8DH 90H 90H 91H 92H 98H 99H 9AH 9BH 9CH 9DH A0H A0H A1H
P0 DIR0 SP DPL DPH WDTL WDTH WDTREL PCON TCON TMOD TL0 TL1 TH0 TH1 P1 DIR1 XPAGE DPSEL S0CON S0BUF IEN2 S1CON S1BUF S1RELL P2 DIR2
.6 .6 .6 .6 .6 .6 .6 .6 PDS TR1 C/T .6 .6 .6 .6 CLKOUT .6 .6 – SM1 .6 – S1P .6 .6 .6 .6
.5 .5 .5 .5 .5 .5 .5 .5 IDLS TF0 M1 .5 .5 .5 .5 T2EX .5 .5 – SM20 .5 ECR SM21 .5 .5 .5 .5
.4 .4 .4 .4 .4 .4 .4 .4 SD TR0 M0 .4 .4 .4 .4 INT2 .4 .4 – REN0 .4 ECS REN1 .4 .4 .4 .4
.3 .3 .3 .3 .3 .3 .3 .3 GF1 IE1 GATE .3 .3 .3 .3 INT6 .3 .3 – TB80 .3 ECT TB81 .3 .3 .3 .3
.2 .2 .2 .2 .2 .2 .2 .2 GF0 IT1 C/T .2 .2 .2 .2 INT5 .2 .2 .2 RB80 .2 ECMP RB81 .2 .2 .2 .2 .2
.1 .1 .1 .1 .1 .1 .1 .1 PDE IE0 M1 .1 .1 .1 .1 INT4 .1 .1 .1 TI0 .1 – TI1 .1 .1 .1 .1 .1
.0 .0 .0 .0 .0 .0 .0 .0 IDLE IT0 M0 .0 .0 .0 .0 INT3 .0 .0 .0 RI0 .0 ES1 RI1 .0 .0 .0 .0 .0
– – – – – – – – – – – – –
PDIR=0
SMOD TF1 GATE .7 .7 .7 .7 T2 .7 .7 – SM0 .7 – SM .7 .7 .7 .7
PDIR=1
– – – – – – – –
PDIR=0 PDIR=1
COMSETL 00H .7 .6 .5 .4 .3 1) X means that the value is indeterminate or the location is reserved. 2) SFRs with a comment in this column are mapped registers. Shaded registers are bit-addressable special function registers.
–
Semiconductor Group
3-23
1997-10-01
Memory Organization C509-L
Table 3-5 Contents of the SFRs, SFRs in numeric order of their addresses (cont’d)
Addr Register Content Bit 7 after Reset 1) .7 .7 .7 .7 .7 EAL Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Mapped by 2) – – – – – – – –
PDIR=0 PDIR=1
A2H A3H A4H A5H A6H A8H A9H AAH B0H B0H B1H B2H B4H B8H B9H BAH BBH BCH BEH BFH BFH C0H C1H
COMSETH 00H COMCLRL 00H COMCLRH 00H SETMSK 00H CLRMSK IEN0 IP0 S0RELL P3 DIR3 SYSCON 00H 00H 00H D9H FFH FFH
.6 .6 .6 .6 .6 WDT
.5 .5 .5 .5 .5 ET2 .5 .5 T1 .5 1 – T2P1 EX6 .5 – – – – ICC15
EICC15
.4 .4 .4 .4 .4 ES0 .4 .4 T0 .4 RMAP EA1 T2P0 EX5 .4 – – – – ICC14
EICC14
.3 .3 .3 .3 .3 ET1 .3 .3 INT1 .3 – EA0 T1P1 EX4 .3 – – CT1F ECT1 ICC13
EICC13
.2 .2 .2 .2 .2 EX1 .2 .2 INT0 .2 –
.1 .1 .1 .1 .1 ET0 .1 .1 TxD0 .1
.0 .0 .0 .0 .0 EX0 .0 .0 RxD0 .0
OWDS WDTS .7 RD .7 CLKP ESWC WDTP .6 WR .6 PMOD SWC S0P
1010. XX01B SYSCON1 00XX. 3) XEE0B PRSC IEN1 IP1 S0RELH S1RELH CT1CON IEN3 IRCON2 EICC1 IRCON0 CCEN 1101. 0101B 00H 0X00. 0000B XXXX. XX11B XXXX. XX11B X1XX. 0000B XXXX. 00XXB 00H FFH 00H 00H
XMAP1 XMAP0 – – – – – – –
PRGEN1 PRGEN0 SWAP
T1P0 EX3 .2 – –
T0P1 EX2 .1 .1 .1
T0P0 EADC .0 .0 .0
EXEN2 SWDT PDIR – – – – ICC17
EICC17
– – – CT1P – ICC16
EICC16
CLK12 CLK11 CLK10 – ECC1 ICC12
EICC12
– ICC11
EICC11
– ICC10
EICC10
–
PDIR=0 PDIR=1
EXF2
COCAH 3
TF2
IEX6
IEX5
IEX4
IEX3
IEX2
IADC
–
COCAL3 COCAH 2
COCAL2 COCAH 1
COCAL1 COCAH 0
COCAL0 –
1) X means that the value is indeterminate or the location is reserved. 2) SFRs with a comment in this column are mapped registers. 3) “E” means that the value of the bit is defined by the logic level at pin PRGEN at the rising edge of the RESET or HWPD signals. Shaded registers are bit-addressable special function registers.
Semiconductor Group
3-24
1997-10-01
Memory Organization C509-L
Table 3-5 Contents of the SFRs, SFRs in numeric order of their addresses (cont’d)
Addr Register Content Bit 7 after Reset 1) 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H .7 .7 .7 .7 .7 .7 T2PS
COCO EN1
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mapped by 2) – – – – – – – – – – – – – – –
C2H C3H C4H C5H C6H C7H C8H C9H CAH CBH CCH CDH CEH CFH D0H D1H D2H D2H D3H D3H D4H D4H D5H D5H D6H D6H D7H D7H D8H D9H
CCL1 CCH1 CCL2 CCH2 CCL3 CCH3 T2CON CC4EN CRCL CRCH TL2 TH2 CCL4 CCH4 PSW IRCON1 CML0 CC1L0 CMH0 CC1H0 CML1 CC1L1 CMH1 CC1H1 CML2 CC1L2 CMH2 CC1H2 ADCON0 ADDATH
.6 .6 .6 .6 .6 .6 I3FR
COCO N2
.5 .5 .5 .5 .5 .5 I2FR
COCO N1
.4 .4 .4 .4 .4 .4 T2R1
COCO N0
.3 .3 .3 .3 .3 .3 T2R0
COCO EN0
.2 .2 .2 .2 .2 .2 T2CM
COCAH 4
.1 .1 .1 .1 .1 .1 T2I1
COCAL 4
.0 .0 .0 .0 .0 .0 T2I0
COMO
.7 .7 .7 .7 .7 .7 CY
.6 .6 .6 .6 .6 .6 AC
.5 .5 .5 .5 .5 .5 F0
.4 .4 .4 .4 .4 .4 RS1
.3 .3 .3 .3 .3 .3 RS0
.2 .2 .2 .2 .2 .2 OV
.1 .1 .1 .1 .1 .1 F1
.0 .0 .0 .0 .0 .0 P
ICMP7 ICMP6 ICMP5 ICMP4 ICMP3 ICMP2 ICMP1 ICMP0 – .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 BD .7 (MSB) .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 CLK .6 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 ADEX .5 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 BSY .4 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 ADM .3 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 MX2 .2 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 MX1 .1 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 MX0 .0
RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1
– –
1) X means that the value is indeterminate or the location is reserved. 2) SFRs with a comment in this column are mapped registers. Shaded registers are bit-addressable special function registers.
Semiconductor Group
3-25
1997-10-01
Memory Organization C509-L
Table 3-5 Contents of the SFRs, SFRs in numeric order of their addresses (cont’d)
Addr Register Content Bit 7 after Reset 1) 00H – 0100. 0000B – 00H 00H 00H 00H 00H 0100. 0000B 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H FFH FFH XXH XXH XXH XXH XXH .7 .7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Mapped by 2) – – – –
RMAP=0 RMAP=1 RMAP=0 RMAP=1
DAH DBH DCH DDH DEH DEH DFH DFH E0H E1H E2H E2H E3H E3H E4H E4H E5H E5H E6H E6H E7H E7H E8H E8H E9H EAH EBH ECH EDH
ADDATL P7 ADCON1 P8 CTRELL CT1RELL CTRELH CT1RELH ACC CTCON CML3 CC1L3 CMH3 CC1H3 CML4 CC1L4 CMH4 CC1H4 CML5 CC1L5 CMH5 CC1H5 P4 DIR4 MD0 MD1 MD2 MD3 MD4
.6 (LSB) .6
– .5
– .4
– .3
– .2 MX2 .2 .2 .2 .2 .2 .2 CLK2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 CM2 .2 .2 .2 .2 .2 .2
– .1 MX1 .1 .1 .1 .1 .1 .1 CLK1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 CM1 .1 .1 .1 .1 .1 .1
– .0 MX0 .0 .0 .0 .0 .0 .0 CLK0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 CM0 .0 .0 .0 .0 .0 .0
ADCL1 ADCL0 ADST1 ADST0 MX3 – .7 .7 .7 .7 .7 .6 .6 .6 .6 .6 .6 .5 .5 .5 .5 .5 .5 ICR .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 CM5 .5 .5 .5 .5 .5 .5 .4 .4 .4 .4 .4 .4 ICS .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 CM4 .4 .4 .4 .4 .4 .4 .3 .3 .3 .3 .3 .3 CTF .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 CM3 .3 .3 .3 .3 .3 .3
– –
RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 PDIR=0 PDIR=1
T2PS1 CTP .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 CM7 .7 .7 .7 .7 .7 .7 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 CM6 .6 .6 .6 .6 .6 .6
– – – – –
1) X means that the value is indeterminate or the location is reserved. 2) SFRs with a comment in this column are mapped registers. Shaded registers are bit-addressable special function registers.
Semiconductor Group
3-26
1997-10-01
Memory Organization C509-L
Table 3-5 Contents of the SFRs, SFRs in numeric order of their addresses (cont’d)
Addr Register Content Bit 7 after Reset 1) XXH 0XXX. XXXXB 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H 00H FFH FFH FFH FFH FFH FFH .7 MDEF .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 .7 CCM7 .7 CC17 .7 .7 .7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Mapped by 2) – – –
RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 RMAP=0 RMAP=1 PDIR=0 PDIR=1 PDIR=0 PDIR=1 PDIR=0 PDIR=1
EEH EFH F0H F2H F2H F3H F3H F4H F4H F5H F5H F6H F6H F7H F7H F8H F8H F9H F9H FAH FAH
MD5 ARCON B CML6 CC1L6 CMH6 CC1H6 CML7 CC1L7 CMH7 CC1H7 CMEN CC1EN CMSEL CAFR P5 DIR5 P9 DIR9 P6 DIR6
.6 MDOV .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6 CCM6 .6 CC16 .6 .6. .6
.5 SLR .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 CCM5 .5 CC15 .5 .5 .5
.4 SC.4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 CCM4 .4 CC14 .4 .4 .4
.3 SC.3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 CCM3 .3 CC13 .3 .3 .3
.2 SC.2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 CCM2 .2 CC12 .2 TxD1 .2
.1 SC.1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 CCM1 .1 CC11 .1 RxD1 .1
.0 SC.0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 CCM0 .0 CC10 .0 ADST .0
1) X means that the value is indeterminate or the location is reserved. 2) SFRs with a comment in this column are mapped registers. Shaded registers are bit-addressable special function registers.
Semiconductor Group
3-27
1997-10-01
External Bus Interface C509-L
4
External Bus Interface
The C509-L allows for external memory expansion. To accomplish this, the external bus interface common to most 8051-based microcontrollers is employed. 4.1 Accessing External Memory
It is possible to distinguish between accesses to external program memory and external data memory or other peripheral components respectively. This distinction is made by hardware: accesses to external program memory use the signal PSEN (program store enable) as a read strobe. Accesses to external data memory use RD and WR to strobe the memory (alternate functions of P3.7 and P3.6). Port 0 and port 2 (with exceptions) are used to provide data and address signals. In this section only the port 0 and port 2 functions relevant to external memory accesses are described. Fetches from external program memory always use a 16-bit address. Accesses to external data memory can use either a 16-bit address (MOVX @DPTR) or an 8-bit address (MOVX @Ri). 4.1.1 Role of P0 and P2 as Data/Address Bus When used for accessing external memory, port 0 provides the data byte time-multiplexed with the low byte of the address. In this state, port 0 is disconnected from its own port latch, and the address/ data signal drives both FETs in the port 0 output buffers. Thus, in this application, the port 0 pins are not open-drain outputs and do not require external pullup resistors. During any access to external memory, the CPU writes FFH to the port 0 latch (the special function register), thus obliterating whatever information the port 0 SFR may have been holding. Whenever a 16-bit address is used, the high byte of the address comes out on port 2, where it is held for the duration of the read or write cycle. During this time, the port 2 lines are disconnected from the port 2 latch (the special function register). Thus the port 2 latch does not have to contain 1s, and the contents of the port 2 SFR are not modified. If an 8-bit address is used (MOVX @Ri), the contents of the port 2 SFR remain at the port 2 pins throughout the external memory cycle. This will facilitate paging. It should be noted that, if a port 2 pin outputs an address bit that is a 1, strong pullups will be used for the entire read/write cycle and not only for two oscillator periods.
Semiconductor Group
4-1
1997-10-01
External Bus Interface C509-L
4.1.2 Timing The timing of the external bus interface, in particular the relationship between the control signals ALE, PSEN, RD, WR and information on port 0 and port 2, is illustrated in figure 4-1 a) and b). Data memory: in a write cycle, the data byte to be written appears on port 0 just before WR is activated and remains there until after WR is deactivated. In a read cycle, the incoming byte is accepted at port 0 before the read strobe is deactivated.
Program memory: Signal PSEN functions as a read strobe. 4.1.3 External Program Memory Access The external program memory is accessed whenever signal EA is active (low): Due to the 64K internal ROM, no mixed internal/external program memory execution is possible. When the CPU is executing out of external program memory, all 8 bits of port 2 are dedicated to an output function and may not be used for general-purpose I/O. The contents of the port 2 SFR however is not affected. During external program memory fetches port 2 lines output the high byte of the PC, and during accesses to external data memory they output either DPH or the port 2 SFR (depending on whether the external data memory access is a MOVX @DPTR or a MOVX @Ri). When the C509-L executes instructions from external program memory, port 2 is at all times dedicated to output the high-order address byte. This means that port 0 and port 2 of the C509-L can never be used as general-purpose I/O. 4.1.4 PSEN, Program Store Enable The read strobe for external fetches is PSEN. PSEN is not activated for internal fetches. When the CPU is accessing external program memory, PSEN is activated twice every cycle (except during a MOVX instruction) no matter whether or not the byte fetched is actually needed for the current instruction. When PSEN is activated its timing is not the same as for RD. A complete RD cycle, including activation and deactivation of ALE and RD, takes 6 oscillator periods. A complete PSEN cycle, including activation and deactivation of ALE and PSEN takes 3 oscillator periods. The execution sequence for these two types of read cycles is shown in figure 4-1 a) and b). 4.1.5 Overlapping External Data and Program Memory Spaces In some applications it is desirable to execute a program from the same physical memory that is used for storing data. In the C509-L the external program and data memory spaces can be combined by AND-ing PSEN and RD. A positive logic AND of these two signals produces an active low read strobe that can be used for the combined physical memory. Since the PSEN cycle is faster than the RD cycle, the external memory needs to be fast enough to adapt to the PSEN cycle.
Semiconductor Group
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External Bus Interface C509-L
a) S1 ALE
One Machine Cycle S2 S3 S4 S5 S6 S1
One Machine Cycle S2 S3 S4 S5 S6
PSEN RD PCH OUT INST. IN PCL OUT PCL OUT valid b) S1 ALE INST. IN PCL OUT PCL OUT valid PCH OUT INST. IN PCL OUT PCL OUT valid PCH OUT INST. IN PCL OUT PCL OUT valid PCH OUT INST. IN (A) without MOVX
P2
P0
One Machine Cycle S2 S3 S4 S5 S6 S1
One Machine Cycle S2 S3 S4 S5 S6
PSEN (B) with MOVX PCH OUT INST. IN PCL OUT PCL OUT valid INST. IN DPL or Ri valid DPH OUT OR P2 OUT DATA IN PCL OUT PCL OUT valid PCH OUT INST. IN
MCT03220
RD
P2
P0
Figure 4-1 External Program Memory Execution
Semiconductor Group
4-3
1997-10-01
External Bus Interface C509-L
4.1.6 ALE, Address Latch Enable The main function of ALE is to provide a properly timed signal to latch the low byte of an address from P0 into an external latch during fetches from external memory. The address byte is valid at the negative transition of ALE. For that purpose, ALE is activated twice every machine cycle. This activation takes place even if the cycle involves no external fetch. The only time no ALE pulse comes out is during an access to external data memory when RD/WR signals are active. The first ALE of the second cycle of a MOVX instruction is missing (see figure 4-1 b). Consequently, in any C509-L system that does not use data memory, ALE is activated at a constant rate of 1/3 of the oscillator frequency and can be used for external clocking or timing purposes. As a reserved function for future versions, the C509-L allows to switch off the ALE output signal by a bit in SFR SYSCON. If EA=0 (this is always the case for the C509-L), the ALE generation is always enabled and resetting of bit 5 of SFR SYSCON has no effect. Special Function Register SYSCON (Address B1H) Bit No. MSB 7 B1H Reset Value : 1010XX01B LSB 0 SYSCON
6
5 1
4 RMAP
3 –
2 –
1
CLKP PMOD
XMAP1 XMAP0
The functions of the shaded bits are not described in this section. Bit Bit 5 Function Reserved bit for future use: Enable/disable ALE output. Bit 5 is at “1” after reset and can be written with “0” or “1”.
Semiconductor Group
4-4
1997-10-01
External Bus Interface C509-L
4.2
Enhanced Hooks Emulation Concept
The Enhanced Hooks Emulation Concept of the C500 microcontroller family is a new, innovative way to control the execution of C500 MCUs and to gain extensive information on the internal operation of the controllers. Emulation of on-chip ROM based programs is possible, too (not true for the C509-l, because it lacks internal program memory). Each production chip has built-in logic for the support of the Enhanced Hooks Emulation Concept. Therefore, no costly bond-out chips are necessary for emulation. This also ensure that emulation and production chips are identical. The Enhanced Hooks TechnologyTM, which requires embedded logic in the C500 allows the C500 together with an EH-IC to function similar to a bond-out chip. This simplifies the design and reduces costs of an ICE-system. ICE-systems using an EH-IC and a compatible C500 are able to emulate all operating modes of the different versions of the C500 microcontrollers. This includes emulation of ROM, ROM with code rollover and ROMless modes of operation. It is also able to operate in single step mode and to read the SFRs after a break.
ICE-System Interface to Emulation Hardware
SYSCON PCON TCON
RESET EA ALE PSEN
RSYSCON RPCON RTCON
EH-IC
C500 MCU
Optional I/O Ports
Port 0 Port 2
Enhanced Hooks Interface Circuit
Port 3
Port 1
RPort 2 RPort 0
TEA TALE TPSEN
Target System Interface
MCS02647
Figure 4-2 Basic C500 MCU Enhanced Hooks Concept Configuration Port 0, port 2 and some of the control lines of the C500 based MCU are used by Enhanced Hooks Emulation Concept to control the operation of the device during emulation and to transfer informations about the program execution and data transfer between the external emulation hardware (ICE-system) and the C500 MCU.
Semiconductor Group
4-5
1997-10-01
External Bus Interface C509-L
4.3
Eight Datapointers for Faster External Bus Access
4.3.1 The Importance of Additional Datapointers The standard 8051 architecture provides just one 16-bit pointer for indirect addressing of external devices (memories, peripherals, latches, etc.). Except for a 16-bit “move immediate” to this datapointer and an increment instruction, any other pointer handling is to be handled bytewise. For complex applications with peripherals located in the external data memory space (e.g. CAN controller) or extended data storage capacity this turned out to be a “bottle neck” for the 8051’s communication to the external world. Especially programming in high-level languages (PLM51, C51, PASCAL51) requires extended RAM capacity and at the same time a fast access to this additional RAM because of the reduced code efficiency of these languages. 4.3.2 How the Eight Datapointers of the C509-L are Realized Simply adding more datapointers is not suitable because of the need to keep up 100% compatibility to the 8051 instruction set. This instruction set, however, allows the handling of only one single 16bit datapointer (DPTR, consisting of the two 8-bit SFRs DPH and DPL). To meet both of the above requirements (speed up external accesses, 100% compatibility to 8051 architecture) the C509-L contains a set of eight 16-bit registers from which the actual datapointer can be selected. This means that the user’s program may keep up to eight 16-bit addresses resident in these registers, but only one register at a time is selected to be the datapointer. Thus the datapointer in turn is accessed (or selected) via indirect addressing. This indirect addressing is done through a special function register called DPSEL (data pointer select register). All instructions of the C509-L which handle the datapointer therefore affect only one of the eight pointers which is addressed by DPSEL at that very moment. Figure 4-3 illustrates the addressing mechanism: a 3-bit field in register DPSEL points to the currently used DPTRx. Any standard 8051 instruction (e.g. MOVX @DPTR, A - transfer a byte from accumulator to an external location addressed by DPTR) now uses this activated DPTRx.
Special Function Register DPSEL (Address 92H) Bit No. MSB 7 92H –
Reset Value : XXXXX000B LSB 0 .0 DPSEL
6 –
5 –
4 –
3 –
2 .2
1 .1
Bit – DPSEL.2-0
Function Reserved bits for future use. Data pointer select bits DPSEL.2-0 defines the number of the actual active data pointer.DPTR0-7.
Semiconductor Group
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1997-10-01
External Bus Interface C509-L
----DPSEL(92 H) DPSEL .2 0 0 0 0 1 1 1 1 .1 0 0 1 1 0 0 1 1 .0 0 1 0 1 0 1 0 1
.2 .1 .0 DPTR7 Selected Datapointer DPTR 0 DPTR 1 DPTR 2 DPTR 3 DPTR 4 DPTR 5 DPTR 6 DPTR 7 External Data Memory
MCD00779
DPTR0 DPH(83 H ) DPL(82 H)
Figure 4-3 Accessing of External Data Memory via Multiple Datapointers 4.3.3 Advantages of Multiple Datapointers Using the above addressing mechanism for external data memory results in less code and faster execution of external accesses. Whenever the contents of the datapointer must be altered between two or more 16-bit addresses, one single instruction, which selects a new datapointer, does this job. lf the program uses just one datapointer, then it has to save the old value (with two 8-bit instructions) and load the new address, byte by byte. This not only takes more time, it also requires additional space in the internal RAM. 4.3.4 Application Example and Performance Analysis The following example shall demonstrate the involvement of multiple data pointers in a table transfer from the code memory to external data memory. Start address of ROM source table: Start address of table in external RAM: 1FFFH 2FA0H
Semiconductor Group
4-7
1997-10-01
External Bus Interface C509-L
Example 1: Using only One Datapointer (Code for an 8051) Initialization Routine MOV MOV MOV MOV LOW(SRC_PTR), #0FFH HIGH(SRC_PTR), #1FH LOW(DES_PTR), #0A0H HIGH(DES_PTR), #2FH ;Initialize shadow_variables with source_pointer ;Initialize shadow_variables with destination_pointer
Table Look-up Routine under Real Time Conditions PUSH PUSH MOV MOV ;INC ;CJNE MOVC MOV MOV MOV MOV INC MOVX MOV MOV POP POP ; DPL DPH DPL, LOW(SRC_PTR) DPH, HIGH(SRC_PTR) DPTR … A,@DPTR LOW(SRC_PTR), DPL HIGH(SRC_PTR), DPH DPL, LOW(DES_PTR) DPH, HIGH(DES_PTR) DPTR @DPTR, A LOW(DES_PTR), DPL HIGH(DES_PTR),DPH DPH DPL ; Number of cycles ;Save old datapointer 2 ; 2 ;Load Source Pointer 2 ; 2 Increment and check for end of table (execution time not relevant for this consideration) – ;Fetch source data byte from ROM table 2 ;Save source_pointer and 2 ;load destination_pointer 2 ; 2 ; 2 ;Increment destination_pointer ;(ex. time not relevant) – ;Transfer byte to destination address 2 ;Save destination_pointer 2 ; 2 ;Restore old datapointer 2 ; 2 Total execution time (machine cycles): 28
Semiconductor Group
4-8
1997-10-01
External Bus Interface C509-L
Example 2: Using Two Datapointers (Code for an C509) Initialization Routine MOV MOV MOV MOV DPSEL, #06H DPTR, #1FFFH DPSEL, #07H DPTR, #2FA0H ;Initialize DPTR6 with source pointer ;Initialize DPTR7 with destination pointer
Table Look-up Routine under Real Time Conditions PUSH MOV ;INC ;CJNE MOVC MOV MOVX POP DPSEL DPSEL, #06H DPTR … A,@DPTR DPSEL, #07H @DPTR, A DPSEL ; Number of cycles ;Save old source pointer 2 ;Load source pointer 2 Increment and check for end of table (execution time not relevant for this consideration) – ;Fetch source data byte from ROM table 2 ;Save source_pointer and ;load destination_pointer 2 ;Transfer byte to destination address 2 ;Save destination pointer and ;restore old datapointer 2 Total execution time (machine cycles): 12
;
The above example shows that utilization of the C509’s multiple datapointers can make external bus accesses two times as fast as with a standard 8051 or 8051 derivative. Here, four data variables in the internal RAM and two additional stack bytes were spared, too. This means for some applications where all eight datapointers are employed that an C509 program has up to 24 byte (16 variables and 8 stack bytes) of the internal RAM free for other use.
Semiconductor Group
4-9
1997-10-01
External Bus Interface C509-L
4.4
XRAM Operation
The XRAM in the C509-L is a memory area that is logically located at the upper end of the external memory space, but is integrated on the chip. Because the XRAM is used in the same way as external data memory the same instruction types (MOVX) must be used for accessing the XRAM. 4.4.1 XRAM Access Control Two bits in SFR SYSCON, XMAP0 and XMAP1, control the accesses to the XRAM. XMAP0 is a general access enable/disable control bit and XMAP1 controls the external signal generation during XRAM accesses. Special Function Register SYSCON (Address B1H) Bit No. MSB 7 B1H Reset Value : 1010XX01B LSB 0 SYSCON
6
5 1
4 RMAP
3 –
2 –
1
CLKP PMOD
XMAP1 XMAP0
The functions of the shaded bits are not described in this section. Bit – XMAP1 Function Reserved bits for future use. XRAM visible access control Control bit for RD/WR signals during XRAM accesses. If addresses are outside the XRAM address range or if XRAM is disabled, this bit has no effect. XMAP1 = 0: The signals RD and WR are not activated during accesses to the XRAM XMAP1 = 1: Ports 0, 2 and the signals RD and WR are activated during accesses to XRAM. In this mode, address and data information during XRAM/CAN Controller accesses are visible externally. Global XRAM access enable/disable control XMAP0 = 0: The access to XRAM is enabled. XMAP0 = 1: The access to XRAM is disabled (default after reset!). All MOVX accesses are performed via the external bus. Further, this bit is hardware protected.
XMAP0
When bit XMAP1 in SFR SYSCON is set, during all accesses to the XRAM RD and WR become active and port 0 and 2 drive the actual address/data information which is read/written from/to the XRAM. This feature allows to check externally the internal data transfers to the XRAM. When port 0 and 2 are used for I/O purposes, the XMAP1 bit should not be set. Otherwise the I/O function of the port 0 and port 2 lines is interrupted.
Semiconductor Group
4-10
1997-10-01
External Bus Interface C509-L
After a reset operation, bit XMAP0 is reset. This means that the accesses to the XRAM is generally disabled. In this case, all accesses using MOVX instructions with an address in the range of F400H to FFFFH generate external data memory bus cycles. When XMAP0 is set, the access to the XRAM is enabled and all accesses using MOVX instructions with an address in the range of F400H to FFFFH will access internally the XRAM. Bit XMAP0 is hardware protected. If it is reset once (XRAM access enabled) it cannot be set by software. Only a reset operation will set the XMAP0 bit again. This hardware protection mechanism is done by an unsymmetric latch at the XMAP0 bit. A unintentional disabling of XRAM could be dangerous since indeterminate values could be read from external bus. To avoid this the XMAP0 bit is forced to '1' only by a reset operation. Additionally, during reset an internal capacitor is loaded. So the reset state is a disabled XRAM. Because of the load time of the capacitor, XMAP0 bit once written to '0' (that is, discharging the capacitor) cannot be set to '1' again by software. On the other hand any distortion (software hang up, noise,...) is not able to load this capacitor, too. That is, the stable status is XRAM enabled. The clear instruction for the XMAP0 bit should be integrated in the program initialization routine before the XRAM is used. In extremely noisy systems the user may have redundant clear instructions.
Semiconductor Group
4-11
1997-10-01
External Bus Interface C509-L
4.4.2
Accesses to XRAM using the DPTR (16-bit Addressing Mode)
The XRAM can be accessed by two read/write instructions, which use the 16-bit DPTR for indirect addressing. These instructions are: – MOVX – MOVX A, @DPTR @DPTR, A (Read) (Write)
For accessing the XRAM, the effective address stored in DPTR must be in the range of F400H to FFFFH. 4.4.3 Accesses to XRAM using the Registers R0/R1 The 8051 architecture provides also instructions for accesses to external data memory range which use only an 8-bit address (indirect addressing with registers R0 or R1). The instructions are: MOVX MOVX A, @ Ri @Ri, A (Read) (Write)
In application systems, either a real 8-bit bus (with 8-bit address) is used or Port 2 serves as page register which selects pages of 256-Byte. However, the distinction, whether Port 2 is used as general purpose I/0 or as “page address” is made by the external system design. From the device's point of view it cannot be decided whether the Port 2 data is used externally as address or as I/0 data. Hence, a special page register is implemented into the C509-L to provide the possibility of accessing the XRAM also with the MOVX @Ri instructions, i.e. XPAGE serves the same function for the XRAM as Port 2 for external data memory.
Special Function Register XPAGE (Address 91H) Bit No. MSB 7 91H .7
Reset Value : 00H LSB 0 .0 XPAGE
6 .6
5 .5
4 .4
3 .3
2 .2
1 .1
Bit XPAGE.7-0
Function XRAM high address XPAGE.7-0 is the address part A15-A8 when 8-bit MOVX instructions are used to access the internal XRAM.
Figures 4-4 and 4-6 show the dependencies of XPAGE- and Port 2 - addressing in order to explain the differences in accessing XRAM/CAN controller, ext. RAM or what is to do when Port 2 is used as an I/O-port.
Semiconductor Group
4-12
1997-10-01
External Bus Interface C509-L
Port 0
Address/Data
XRAM XPAGE Write to Port 2
Port 2
Page Address
MCB02112
Figure 4-4 Write Page Address to Port 2 “MOV P2,pageaddress” will write the page address to Port 2 and the XPAGE-Register. When external RAM is to be accessed in the XRAM address range (F400H - FFFFH), XRAM has to be disabled. When additional external RAM is to be addressed in an address range ≤ XRAM (F400H) XRAM may remain being enabled and there is no need to overwrite XPAGE by a second move.
Semiconductor Group
4-13
1997-10-01
External Bus Interface C509-L
Port 0
Address/Data
XRAM XPAGE Write to XPAGE
Port 2
Address/ I/O-Data
MCB02113
Figure 4-5 Write Page Address to XPAGE The page address is only written to the XPAGE register. Port 2 is available for addresses or I/O data. See figure 4-6 to see what happens when Port 2 is used as I/O-Port.
Semiconductor Group
4-14
1997-10-01
External Bus Interface C509-L
Port 0
Address/Data
XRAM XPAGE Write I/O Data to Port 2 Port 2 I/O-Data
MCB02114
Figure 4-6 Usage of Port 2 as I/O Port
At a write to port 2, the XRAM address in the XPAGE register will be overwritten because of the concurrent write to port 2 and XPAGE register. So, whenever XRAM is used and the XRAM address differs from the byte written to port 2 latch it is absolutely necessary to rewrite XPAGE with the page address.
Example: I/O data at port 2 shall be AAH. A byte shall be fetched from XRAM at address F830H. MOV MOV MOV MOVX R0, #30H P2, #0AAH XPAGE, #0F8H A, @R0 ; ; P2 shows AAH ; P2 still shows AAH but XRAM is addressed ; the contents of XRAM at F830H is moved to accumulator
Semiconductor Group
4-15
1997-10-01
External Bus Interface C509-L
The register XPAGE provides the upper address byte for accesses to XRAM with MOVX @Ri instructions. If the address formed by XPAGE and Ri points outside the XRAM address range, an external access is performed. For the C509-L the contents of XPAGE must be greater or equal F3H in order to use the XRAM/. Thus, the register XPAGE is used for addressing of the XRAM; additionally its contents are used for generating the internal XRAM select. If the contents of XPAGE is less than the XRAM address range then an external bus access is performed where the upper address byte is provided by P2 and not by XPAGE! The software has to distinguish two cases, if the MOVX @Ri instructions with paging shall be used: a) Access to XRAM: b) Access to external memory: The upper address byte must be written to XPAGE or P2; both writes select the XRAM address range. The upper address byte must be written to P2; XPAGE will be loaded with the same address in order to deselect the XRAM.
4.4.4
Reset Operation of the XRAM
The content of the XRAM is not affected by a reset. After power-up the content is undefined, while it remains unchanged during and after a reset as long as the power supply is not turned off. If a reset occurs during a write operation to XRAM, the content of a XRAM memory location depends on the cycle in which the active reset signal is detected (MOVX is a 2-cycle instruction): Reset during 1st cycle : The new value will not be written to XRAM. The old value is not affected. Reset during 2nd cycle : The old value in XRAM is overwritten by the new value.
4.4.5 Behaviour of Port0 and Port2 The behaviour of Port 0 and P2 during a MOVX access depends on the control bits in register SYSCON and on the state of pin EA. The table 4-1 lists the various operating conditions. It shows the following characteristics: a) Use of P0 and P2 pins during the MOVX access. Bus: The pins work as external address/data bus. If (internal) XRAM is accessed, the data written to the XRAM can be seen on the bus in debug mode. I/0: The pins work as Input/Output lines under control of their latch. b) Activation of the RD and WR pin during the access. c) Use of internal or external XDATA memory. The shaded areas describe the standard operation as each 80C51 device without on-chip XRAM behaves.
Semiconductor Group
4-16
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Semiconductor Group 4-17 1997-10-01
EA = 0 XMAP1, XMAP0 00 MOVX @DPTR DPTR < XRAM address range DPTR ≥ XRAM address range MOVX @ Ri XPAGE < XRAM addr.page range XPAGE ≥ XRAM addr.page range a)P0/P2→Bus b)RD/WR active c)ext.memory is used a)P0/P2→Bus (WR / RD Data) b)RD/WR inactive c)XRAM is used a)P0→Bus P2→I/O b)RD/WR active c)ext.memory is used a)P0→Bus (WR / RD Data) P2→I/O b)RD/WR inactive c)XRAM is used 10 a)P0/P2→Bus b)RD/WR active c)ext.memory is used X1 a)P0/P2→Bus b)RD/WR active c)ext.memory is used 00 a)P0/P2→Bus b)RD/WR active c)ext.memory is used 10
EA = 1 XMAP1, XMAP0 X1 a)P0/P2→Bus b)RD/WR active c)ext.memory is used a)P0/P2→Bus b)RD/WR active c)ext.memory is used
a)P0/P2→Bus a)P0/P2→Bus a)P0/P2→I/0 (WR / RD Data) b)RD/WR active b)RD/WR active b)RD/WR c)XRAM is used c) ext.memory inactive is used c)XRAM is used a)P0→Bus P2→I/O b)RD/WR active c)ext.memory is used a)P0→Bus P2→I/O b)RD/WR active c)ext.memory is used a)P0→Bus P2→I/O b)RD/WR active c)ext.memory is used
a)P0/P2→Bus a)P0/P2→Bus (WR / RD Data) b)RD/WR active b)RD/WR active c)XRAM is used c) ext.memory is used a)P0→Bus P2→I/O b)RD/WR active c)ext.memory is used a)P0→Bus P2→I/O b)RD/WR active c)ext.memory is used
a)P0→Bus a)P0→Bus a)P2→I/O (WR / RD Data) P2→I/O P0/P2→I/O P2→I/O b)RD/WR active b)RD/WR active b)RD/WR inactive c)XRAM is used c)ext.memory c)XRAM is used is used
a)P0→Bus a)P0→Bus (WR / RD Data) P2→I/O P2→I/O b)RD/WR active b)RD/WR active c)XRAM is used c)ext.memory is used
External Bus Interface C509-L
modes compatible to 8051/C501 family Table 4-1 Behaviour of P0/P2 and RD/WR During MOVX Accesses
Reset / System Clock C509-L
5 5.1
Reset and System Clock Operation Reset Function and Circuitries
The hardware reset function incorporated in the C509-L allows for an easy automatic start-up at a minimum of additional hardware and forces the controller to a predefined default state. The hardware reset function can also be used during normal operation in order to restart the device. This is particularly done when the power-down mode is to be terminated. Additionally to the hardware reset, which is applied externally to the C509-L, there are two internal reset sources, the watchdog timer and the oscillator watchdog. They are described in detail in section 8 "Fail-Save Mechanisms". The actual chapter only deals with the external hardware reset. The reset input is an active low input at pin RESET. An internal Schmitt trigger is used at the input for noise rejection. Since the reset is synchronized internally, the RESET pin must be held low for at least two machine cycles (12 oscillator periods) while the oscillator is running. With the oscillator running the internal reset is executed during the second machine cycle in which RESET is low and is repeated every cycle until RESET goes high again. During reset, pins ALE and PSEN are configured as inputs and should not be stimulated externally. (An external stimulation at these lines during reset activates several test modes which are reserved for test purposes. This in turn may cause unpredictable output operations at several port pins). A pullup resistor is internally connected to VCC to allow a power-up reset with an external capacitor only. An automatic reset can be obtained when VCC is applied by connecting the reset pin to VSS via a capacitor as shown in figure 5-1 a) and c). After VCC has been turned on, the capacitor must hold the voltage level at the reset pin for a specified time below the upper threshold of the Schmitt trigger to effect a complete reset.
Semiconductor Group
5-1
1997-10-01
Reset / System Clock C509-L
The time required for a reset operation is the oscillator start-up time plus 2 machine cycles, which, under normal conditions, must be at least 10 - 20 ms for a crystal oscillator. This requirement is typically met using a capacitor of 4.7 to 10 µF. The same considerations apply if the reset signal is generated externally (figure 5-1 b). In each case it must be assured that the oscillator has started up properly and that at least two machine cycles have passed before the reset signal goes inactive.
Figure 5-1 Reset Circuitries A correct reset leaves the processor in a defined state. The program execution starts at location 0000H. Depending on the state of the PRGEN pin, either external ROM/EPROM is accessed (Normal Mode) or the C509-L starts with the bootstrap loader program located in the Boot ROM (Bootstrap Mode). The default values of the special function registers (SFR) to which they are forced during reset are listed in table 3-4 and 3-5 of chapter 3. After reset is internally accomplished the port latches of ports 0 to 6 are set to FFH. This leaves port 0 floating, since it is an open drain port when not used as data/address bus. All other I/O port lines (ports 1 to 6 and 9) output a one (1). Ports 7 and 8, which are input-only ports, have no internal latch and therefore the contents of the special function registers P7 and P8 depend on the levels applied to ports 7 and 8. The content of the internal RAM of the C509-L is not affected by a reset. After power-up the content is undefined, while it remains unchanged during a reset it the power supply is not turned off.
Semiconductor Group
5-2
1997-10-01
Reset / System Clock C509-L
5.2
Hardware Reset Timing
This section describes the timing of the hardware reset signal. The input pin RESET is sampled once during each machine cycle. This happens in state 5 phase 2. Thus, the external reset signal is synchronized to the internal CPU timing. When the reset is found active (low level at pin RESET) the internal reset procedure is started. lt needs two complete machine cycles to put the complete device to its correct reset state, i.e. all special function registers contain their default values, the port latches contain 1’s etc. Note that this reset procedure is not performed if there is no clock available at the device (This can be avoided using the oscillator watchdog, which provides an auxiliary clock for performing a correct reset without clock at the XTAL1 and XTAL2 pins). The RESET signal must be active for at least two machine cycles; after this time the C509-L remains in its reset state as long as the signal is active. When the signal goes inactive this transition is recognized in the following state 5 phase 2 of the machine cycle. Then the processor starts its address output (when configured for external ROM) in the following state 5 phase 1. One phase later (state 5 phase 2) the first falling edge at pin ALE occurs. Figure 5-2 shows this timing for a configuration with EA = 0 (external program memory). Thus, between the release of the RESET signal and the first falling edge at ALE there is a time period of at least one machine cycle but less than two machine cycles.
Figure 5-2 CPU Timing after Reset
Semiconductor Group
5-3
1997-10-01
Reset / System Clock C509-L
5.3
Fast Internal Reset after Power-On
The C509-L uses the oscillator watchdog unit (see also chapter 8) for a fast internal reset procedure after power-on. Figure 5-3 shows the power-on sequence under control of the oscillator watchdog. Normally the devices of the 8051 family enter their default reset state not before the on-chip oscillator starts. The reason is that the external reset signal must be internally synchronized and processed in order to bring the device into the correct reset state. Especially if a crystal is used the start up time of the oscillator is relatively long (max. 10 ms). During this time period the pins have an undefined state which could have severe effects especially to actuators connected to port pins. In the C509-L the oscillator watchdog unit avoids this situation. In this case, after power-on the oscillator watchdog's RC oscillator starts working within a very short start-up time (typ. less than 2 microseconds). In the following the watchdog circuitry detects a failure condition for the on-chip oscillator because this has not yet started (a failure is always recognized if the watchdog's RC oscillator runs faster than the on-chip oscillator). As long as this condition is detected the watchdog uses the RC oscillator output as clock source for the chip rather than the on-chip oscillator's output. This allows correct resetting of the part and brings also all ports to the defined state (see figure 5-3). Under worst case conditions (fast VCC rise time - e.g. 1µs, measured from VCC = 4.25 V up to stable port condition), the delay between power-on and the correct port reset state is : – Typ.: – Max.: 18 µs 34 µs
The RC oscillator will already run at a VCC below 4.25V (lower specification limit). Therefore, at slower VCC rise times the delay time will be less than the two values given above. After the on-chip oscillator finally has started, the oscillator watchdog detects the correct function; then the watchdog still holds the reset active for a time period of max. 768 cycles of the RC oscillator clock in order to allow the oscillation of the on-chip oscillator to stabilize (figure 5-3, II). Subsequently, the clock is supplied by the on-chip oscillator and the oscillator watchdog's reset request is released (figure 5-3, III). However, an externally applied reset still remains active (figure 5-3, IV) and the device does not start program execution (figure 5-3, V) before the external reset is also released. Although the oscillator watchdog provides a fast internal reset it is additionally necessary to apply the external reset signal when powering up. The reasons are as follows: – – – Termination of Hardware Power-Down Mode (a HWPD signal is overriden by reset) Termination of the Software Power Down Mode Reset of the status flag OWDS that is set by the oscillator watchdog during the power up sequence.
Using a crystal for clock generation, the external reset signal must be hold active at least until the on-chip oscillator has started (max.10 ms) and the internal watchdog reset phase is completed (after phase III in figure 5-3). When an external clock generator is used, phase II is very short. Therefore, an external reset time of typically 1 ms is sufficient in most applications. Generally, for reset time generation at power-on an external capacitor can be applied to the RESET pin.
Semiconductor Group
5-4
1997-10-01
Semiconductor Group
Reset II III IV V Clock from RC-Oscillator, Reset at Ports On-chip oscillator starts; final reset sequence by oscillator WD; max. 768 Cycles Port remains in reset because of ext. reset signal Start of program execution
MCD02722
Ports
Undef.
Figure 5-3 Power-On Reset of the C509-L
On-Chip Oscillator
RC Oscillator
5-5
VCC
RESET
Phase
I
Power On; undef. Port typ. 18 µs max. 34 µs
Reset / System Clock C509-L
1997-10-01
Reset / System Clock C509-L
5.4
Reset Output Pin (RO)
As mentioned before the C509-L internally synchronizes an external reset signal at pin RESET in order to perform a reset procedure. Additionally, the C509-L provides several "fail-save" mechanisms, e.g. watchdog timer and oscillator watchdog, which can internally generate a reset, too. Thus, it is often important to inform also the peripherals external to the chip that a reset is being performed and that the controller will soon start its program again. For that purpose, the C509-L has a pin dedicated to output the internal reset request. This reset output (RO) shows the internal (and already synchronized) reset signal requested by any of the three possible sources in the C509-L: external hardware reset, watchdog timer reset, or oscillator watchdog reset. The duration of the active low signal of the reset output depends on the source which requests it. In the case of the external hardware reset it is the synchronized external reset signal at pin RESET. In the case of a watchdog timer reset or oscillator watchdog reset the RO signal takes at least two machine cycles, which is the minimal duration for a reset request allowed. For details - how the reset requests are OR-ed together and how long they last - see also chapter 8 "Fail-Save Mechanisms" . 5.5 Oscillator and Clock Circuit
XTAL1 and XTAL2 are the output and input of a single-stage on-chip inverter which can be configured with off-chip components as a Pierce oscillator. The oscillator, in any case, drives the internal clock generator. The clock generator provides the internal clock signals to the chip at half the oscillator frequency. These signals define the internal phases, states and machine cycles. Figure 5-4 shows the recommended oscillator circuit.
Figure 5-4 Recommended Oscillator Circuit
Semiconductor Group
5-6
1997-10-01
Reset / System Clock C509-L
In this application the on-chip oscillator is used as a crystal-controlled, positive-reactance oscillator (a more detailed schematic is given in figure 5-5). lt is operated in its fundamental response mode as an inductive reactor in parallel resonance with a capacitor external to the chip. The crystal specifications and capacitances are non-critical. In this circuit 20 pF can be used as single capacitance at any frequency together with a good quality crystal. A ceramic resonator can be used in place of the crystal in cost-critical applications. lt a ceramic resonator is used, C1 and C2 are normally selected to be of somewhat higher values, typically 47 pF. We recommend consulting the manufacturer of the ceramic resonator for value specifications of these capacitors.
Figure 5-5 On-Chip Oscillator Circuitry To drive the C509-L with an external clock source, the external clock signal has to be applied to XTAL2, as shown in figure 5-6. XTAL1 has to be left unconnected. A pullup resistor is suggested (to increase the noise margin), but is optional if VOH of the driving gate corresponds to the VIH2 specification of XTAL2.
Figure 5-6 External Clock Source Semiconductor Group 5-7 1997-10-01
Reset / System Clock C509-L
5.6
System Clock Output
For peripheral devices requiring a system clock, the C509-L provides a clock output signal derived from the oscillator frequency as an alternate output function on pin P1.6/CLKOUT. lf bit CLK is set (bit 6 of special function register ADCON0), a clock signal with 1/6 or 1/12 of the oscillator frequency (depending on bit CLKP in SFR SYSCON) is gated to pin P1.6/CLKOUT. To use this function the port pin must be programmed to a one (1), which is also the default after reset. Special Function Register ADCON0 (Address D8H) Special Function Register SYSCON (Address B1H) MSB DFH BD 7 B1H Reset Value : 00H Reset Value : 1010XX01B LSB D8H MX0 0 SYSCON ADCON0
Bit No. D8H
DEH CLK 6
DDH ADEX 5
DCH BSY 4 RMAP
DBH ADM 3 –
DAH MX2 2 –
D9H MX1 1
CLKP PMOD EALE
XMAP1 XMAP0
These bits are not used in controlling the clock output function. Bit CLK Function Clock output enable bit When set, pin P1.6/CLKOUT outputs the system clock which is 1/6 or 1/12 of the oscillator frequency. Prescaler control for the clock output signal CLKOUT CLKP = 0 : CLKOUT frequency is fOSC/6 CLKP = 1 : CLKOUT frequency is fOSC/12 (default after reset)
CLKP
A timing diagram of the system clock output is shown in figure 5-7. This timing assumes that CLK=1 and CLKP=0. Note : During slow-down operation the frequency of the CLKOUT signal is further divided by eight.
Semiconductor Group
5-8
1997-10-01
Reset / System Clock C509-L
S6
S1 S2 S3 S4 S5 S6
S1 S2 S3 S4 S5 S6
S1 S2
ALE
PSEN
RD,WR
CLKOUT
MCT01858
Figure 5-7 Timing Diagram - System Clock Output
Semiconductor Group
5-9
1997-10-01
On-Chip Peripheral Components C509-L
6
On-Chip Peripheral Components
This chapter gives detailed information about all on-chip peripherals of the C509-L except for the integrated interrupt controller, which is described separately in chapter 7. 6.1 6.1.1 Parallel I/O Port Structures
Digital I/O Ports The C509-L allows for digital I/O on 64 lines grouped into 8 bidirectional 8-bit ports. Each port bit consists of a latch, an output driver and an input buffer. Read and write accesses to the I/O ports P0 through P6 and P9 are performed via their corresponding special function registers P0 to P6 and P9. The port structure of the C509-L is designed to operate either as a quasi-bidirectional port structure, compatible to the standard 8051-Family, or as a genuine bidirectional port structure. This port operating mode can be selected by software (setting or clearing the bit PMOD in the SFR SYSCON). The output drivers of port 0 and 2 and the input buffers of port 0 are also used for accessing external memory. In this application, port 0 outputs the low byte of the external memory address, timemultiplexed with the byte being written or read. Port 2 outputs the high byte of the external memory address when the address is 16 bits wide. Otherwise, the port 2 pins continue emitting the P2 SFR contents. Analog Input Ports Ports 7 and 8 are available as input ports only and provide for two functions. When used as digital inputs, the corresponding SFR’s P7 and P8 contain the digital value applied to port 7 and port 8 lines. When used for analog inputs the desired analog channel is selected by a three-bit field in SFR ADCON0 or a four-bit field in SFR ADCON1. Of course, it makes no sense to output a value to these input-only ports by writing to the SFR’s P7 or P8; this will have no effect. lf a digital value is to be read, the voltage levels are to be held within the input voltage specifications (VIL/VIH). Since P7 and P8 are not bit-addressable registers, all input lines of P7 or P8 are read at the same time by byte instructions. Nevertheless, it is possible to use ports 7 and 8 simultaneously for analog and digital input. However, care must be taken that all bits of P7 or P8 that have an undetermined value caused by their analog function are masked. In order to guarantee a high-quality A/D conversion, digital input lines of port 7 and port 8 should not toggle while a neighboring port pin is executing an A/D conversion. This could produce crosstalk to the analog signal.
Semiconductor Group
6-1
1997-10-01
On-Chip Peripheral Components C509-L
Figure 6-1 shows a functional diagram of a typical bit latch and I/O buffer, which is the core of each of the 8 digital I/O-ports. The bit latch (one bit in the port’s SFR) is represented as a type-D flip-flop, which will clock in a value from the internal bus in response to a “write-to-latch” signal from the CPU. The Q output of the flip-flop is placed on the internal bus in response to a “read-latch” signal from the CPU. The level of the port pin self is placed on the internal bus in response to a “read-pin” signal from the CPU. Some instructions that read from a port activate the “read-port-latch” signal, while others activate the “read-port-pin” signal.
Figure 6-1 Basic Structure of a Port Circuitry
Semiconductor Group
6-2
1997-10-01
On-Chip Peripheral Components C509-L
The shaded area in figure 6-1 shows the control logic in the C509-L, which has been added to the functionality of the standard 8051 digital I/O port structure. This control logic is used to provide an additional bidirectional port structure with CMOS voltage levels. 6.1.1.1 Port Structure Selection
After a reset operation of the C509-L, the quasi-bidirectional 8051-compatible port structure is selected. For selection of the bidirectional port structure (CMOS) the bit PMOD of SFR SYSCON must be set. Because each port pin can be programmed as an input or an output, additionally, after the selection of the bidirectional mode the direction register of the ports must be written (except the analog/digital input ports 7,8). This direction registers are mapped to the port registers. This means, the port register address is equal to its direction register address. Figure 6-2 illustrates the portand direction register configuration.
Figure 6-2 Port Register, Direction Register For the access the direction registers a double instruction sequence must be executed. The first instruction has to set bit PDIR in SFR IP1. Thereafter, a second instruction can read or write the direction registers. PDIR will automatically be cleared after the second machine cycle (S2P2) after having been set. For this time, the access to the direction register is enabled and the register can be read or written. Further, the double instruction sequence as shown in figure 6-2, cannot be interrupted by an interrupt, When the bidirectional port structure is activated (PMOD=1) after a reset, the ports are defined as inputs (direction registers default values after reset are set to FFH). With PMOD = 0 (quasi-bidirectional port structure selected), any access to the direction registers has no effect on the port driver circuitries.
Semiconductor Group
6-3
1997-10-01
On-Chip Peripheral Components C509-L
Special Function Register SYSCON (Address B1H) Special Function Register IP1 (Address B9H) MSB 7
Reset Value : 1010XX01B Reset Value : 0X000000B LSB 0 SYSCON
Bit No. B1H
6
5 1 5 .5
4 RMAP 4 .4
3 – 3 .3
2 – 2 .2
1
CLKP PMOD 7 6 –
XMAP1 XMAP0 1 .1 0 .0
B9H
PDIR
IP1
The shaded bits are not used for port selection.
Bit PMOD
Function Port mode selection PMOD = 0: Quasi-bidirectional port structure is selected (reset value) PMOD = 1: Bidirectional port structure is selected. Direction register enable PDIR = 0: Port register access is enabled (reset value) PDIR = 1: Direction register is enabled. PDIR will automatically be cleared after the second machine cycle (S2P2) after having been set.
PDIR
Direction Registers DIR0-DIR6, DIR9 (Mapped Address = Port Address) MSB 7 .7
Reset Value : FFH LSB 0 .0 Direction Register
Bit No. Address. = Port-Addr.
6 .6
5 .5
4 .4
3 .3
2 .2
1 .1
Bit Bit 7...0
Function Port driver circuitry, input/output selection Bit = 0: Port line is in output mode Bit = 1: Port line is in input mode (reset value). This register can only be read and written by software when bit PDIR (IP1) was set one instruction before.
Semiconductor Group
6-4
1997-10-01
On-Chip Peripheral Components C509-L
6.1.1.2
Quasi-Bidirectional Port Structure
6.1.1.2.1 Basic Port Circuitry of Port 1 to 6 and 9 The basic quasi-bidirectional port structure as shown in the upper part of the schematics of figure 6-1 provides a port driver circuit which is build up by an internal pullup FET as shown in figure 6-3. Each I/O line can be used independently as an input or output. To be used as an input, the port bit stored in the bit latch must contain a one (1) (that means for figure 6-3: Q=0), which turns off the output driver FET n1. Then, for ports 1 to 6 and 9, the pin is pulled high by the internal pullups, but can be pulled low by an external source. When externally pulled low the port pins source current (IIL or ITL). For this reason these ports are sometimes called “quasi-bidirectional”.
Read Latch
VCC
Internal Pull Up Arrangement Q Bit Latch CLK Pin
Int. Bus Write to Latch
D
Q
n1
MCS01823
Read Pin
Figure 6-3 Basic Output Driver Circuit of Ports 1 to 6 and 9
Semiconductor Group
6-5
1997-10-01
On-Chip Peripheral Components C509-L
In fact, the pullups mentioned before and included in figure 6-3 are pullup arrangements as shown in figure 6-4. One n-channel pulldown FET and three pullup FETs are used:
Delay = 1 State
VCC
=1
_
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