Siemens C509-L 8-bit cmos microcontroller Datasheet

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User's Manual 10.97
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8-Bit CMOS Microcontroller
C509-L Data Sheet
Revision History :
10.97
Previous Releases :
06.96 (Original Version)
Page (new
version)
Page (prev. Subjects (changes since last revision)
version)
1-6
1-11
3-1
3-12
1-6
1-11
3-1
3-12
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
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
11-1, 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
Page
1
1.1
1.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Pin Definitions and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
2
2.1
2.2
Fundamental Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
CPU Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
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
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
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
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
Page
5
5.1
5.2
5.3
5.4
5.5
5.6
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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
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
5-1
5-1
5-3
5-4
5-6
5-6
5-8
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
Page
7
7.1
7.2
7.2.1
7.2.2
7.2.3
7.3
7.4
7.5
7.6
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
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
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
9.1
9.2
9.3
9.4
9.5
9.6
9.7
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
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
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
Semiconductor Group
1-4
8-1
8-1
8-2
8-3
8-4
8-4
8-4
8-5
8-5
8-6
1997-10-01
General Information
C509-L
Table of Contents
Page
10.4.2.4
10.5
Selection of Operating Mode 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-27
Description of the Bootstrap Loader Subroutines . . . . . . . . . . . . . . . . . . . . . . . . . 10-29
11
11.1
11.2
11.3
11.4
Device Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A/D Converter Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1
Semiconductor Group
1-5
11-1
11-1
11-1
11-5
11-7
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.
On-Chip Emulation Support Module
C509
Watchdog
RAM
256 x 8
Oscillator
Watchdog
T0
MDU
8-Bit USART
CPU
C500-Core
(8-Dataptr)
T2
8-Bit UART
HW/SW
Power
Down
Modes
Boot ROM 512 x 8
T1
Comp.
Timer 1
Port 9
I/O
10-Bit ADC
Port 8
Port 7
analog/ analog/
digit.
digit.
input
input
Improved functionality in
comparison to the SAB 80C517A.
Port 4
I/O
Port 4
I/O
Port 4
Comp.
Timer 1 Port 4
I/O
Port 6
Port 5
Port 4
I/O
I/O
I/O
I/O
CCU
XRAM
3Kx8
I/O
MCB02493
Figure 1-1
C509-L Functional Units
Semiconductor Group
1-1
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
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
Semiconductor Group
1-2
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
9
8
7
6
1
100
99
98
I/O*)
Function
I/O
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
*) I = Input
O = Output
Semiconductor Group
1-5
1997-10-01
Introduction
C509-L
Table 1-1
Pin Definitions and Functions (cont’d)
Symbol
Pin Number
I/O*)
Function
P9.0 - P9.7
74-77,
5-2
I/O
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
12
–
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
13
–
XTAL1
Output of the inverting oscillator amplifier. This pin is
used for the oscillator operation with crystal or ceramic
resonartor
*) I = Input
O = Output
Semiconductor Group
1-6
1997-10-01
Introduction
C509-L
Table 1-1
Pin Definitions and Functions (cont’d)
Symbol
Pin Number
I/O*)
Function
P2.0 – P2.7
14-21
I/O
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
PSEN / RDF
22
O
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.
ALE
23
O
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.
EA
24
I
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.
PRGEN
25
I
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.
*) I = Input
O = Output
Semiconductor Group
1-7
1997-10-01
Introduction
C509-L
Table 1-1
Pin Definitions and Functions (cont’d)
Symbol
Pin Number
I/O*)
Function
P0.0 – P0.7
26, 27,
30-35
I/O
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
HWPD
36
I
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.
P5.0 - P5.7
44-37
I/O
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
*) I = Input
O = Output
Semiconductor Group
1-8
1997-10-01
Introduction
C509-L
Table 1-1
Pin Definitions and Functions (cont’d)
Symbol
Pin Number
I/O*)
Function
OWE
45
I
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.
P6.0 - P6.7
46-50,
54-56
I/O
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.
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
Pin Number
I/O*)
Function
P8.0 - P8.6
57-60,
51-53
I
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
RO
61
O
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.
P4.0 – P4.7
64-66,
68-72
I/O
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
PE / SWD
67
I
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.
*) I = Input
O = Output
Semiconductor Group
1-10
1997-10-01
Introduction
C509-L
Table 1-1
Pin Definitions and Functions (cont’d)
Symbol
Pin Number
I/O*)
Function
RESET
73
I
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.
VAREF
78
–
Reference voltage for the A/D converter
VAGND
79
–
Reference ground for the A/D converter
P7.0 - P7.7
87-80
I
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
*) 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*)
Function
I/O
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.
90
91
92
93
94
95
96
97
VSS
10, 28, 62, 88
–
Circuit ground potential
VCC
11, 29, 63, 89
–
Supply terminal for all operating modes
*) I = Input
O = Output
Semiconductor Group
1-12
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
ACC 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)
Bit No.
D0H
Reset Value : 00H
MSB
D7H
D6H
D5H
D4H
D3H
D2H
D1H
LSB
D0H
CY
AC
F0
RS1
RS0
OV
F1
P
Bit
Function
CY
Carry Flag
Used by arithmetic instructions.
AC
Auxiliary Carry Flag
Used by instructions which execute BCD operations)
F0
General Purpose Flag
RS1
RS0
Register Bank select control bits
These bits are used to select one of the four register banks.
PSW
RS1
RS0
Function
0
0
Bank 0 selected, data address 00H-07H
0
1
Bank 1 selected, data address 08H-0FH
1
0
Bank 2 selected, data address 10H-17H
1
1
Bank 3 selected, data address 18H-1FH
OV
Overflow Flag
F1
General Purpose Flag
Used by arithmetic instructions.
P
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)
Program Memory
Data Memory
SYSCON1 Bits
Ext.
Int.
Ext.
Int.
PRGEN
1
SWAP
Normal Mode
0000H FFFFH
–
0000H F3FFH
F400H FFFFH
(XRAM)
0
0
XRAM Mode
0200H F3FFH
0000H 01FFH =
Boot ROM;
F400H FFFFH =
(XRAM)
0000H FFFFH
(read only)
–
0
1
Bootstrap Mode
0200H F3FFH
0000H 01FFH =
Boot ROM
0000H F3FFH
F400H FFFFH
(XRAM)
1
0
Programming Mode
0200H FFFFH
0000H 01FFH =
Boot ROM;
F400H FFFFH =
XRAM
0000H FFFFH
(read and
write)
–
1
1
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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).
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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.
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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.
Reset Value : 00XXXEE0B 1)
Special Function Register SYSCON1 (Address B2H)
Bit No.
B2H
MSB
7
6
5
4
3
ESWC
SWC
–
EA1
EA0
2
1
LSB
0
PRGEN1 PRGEN0 SWAP
SYSCON1
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
Function
ESWC
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.
SWC
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’.
–, EA1, EA0
Reserved bits; at read operations these bits are undefined; at write operations to
SYSCON1 these bits can be written with “0” or “1”.
PRGEN1
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.
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3-10
1997-10-01
Memory Organization
C509-L
Bit
Function
PRGEN0
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
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.
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)
Hardware Selection
Normal Mode
PRGEN pin = low
RESET or HWPD:
Software Selection
1
PRGEN pin = don’t care;
4
setting bits PRGEN1,SWAP = 0,0;
executing unlock sequence
2
PRGEN pin = don’t care;
5
setting bits PRGEN1,SWAP = 0,1;
executing unlock sequence
edge
XRAM Mode
from Programming Mode:
setting PRGEN pin = low
Bootstrap Mode
PRGEN pin = high
RESET or HWPD:
Programming Mode
not possible
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
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
7
4
4
5
4
7
5
XRAM Mode
PRGEN1, SWAP = 0,1
Programming Mode
PRGEN1, SWAP = 1,1
2
5
6
6
7
6
Bootstrap Mode
PRGEN1, SWAP = 1,0
3
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)
Code Memory Control
PSEN /
RDF
P3.7 / RD / P3.7 / RD / P3.6 / WR
PSENX
PSENX
Normal Mode
0000H FFFFH
–
XMAP0=1 :
0000H FFFFH
XMAP0=0 :
0000H F3FFH
XMAP0=1 : –
0000H FFFFH
XMAP0=0 :
0000H F3FFH
XRAM Mode
–
0200H F3FFH
–
–
0000H FFFFH
–
Bootstrap Mode
0200H FFFFH
–
0000H F3FFH
0000H F3FFH
–
–
Programming
Mode
–
0200H F3FFH
–
–
0000H FFFFH
0000H FFFFH
Semiconductor Group
Data Memory Control
3-14
PSEN /
RDF
P6.3 /
WRF
–
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
6
Reset Value : 1010XX01B
Reset Value : 0X000000B
5
4
3
2
B1H
CLKP PMOD
1
RMAP
–
–
B9H
PDIR
.5
.4
.3
.2
–
1
LSB
0
XMAP1 XMAP0
.1
.0
SYSCON
IP1
The functions of the shaded bits are not described in this section.
Bit
Function
RMAP
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.
PDIR
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.
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
Symbol
Name
Address Contents after
Reset
CPU
ACC
B
DPH
DPL
DPSEL
PSW
SP
SYSCON1
Accumulator
B-Register
Data Pointer, High Byte
Data Pointer, Low Byte
Data Pointer Select Register
Program Status Word
Stack Pointer
System Control Register 1
E0H 1)
F0H 1)
83H
82H
92H
D0H 1)
81H
B2H
00H
00H
00H
00H
XXXXX000B 3)
00H
07H
00XXXEE0B3)6)
SFR
Mapping
SYSCON 2) System Control Register
B1H
1010XX01B 3)
Interrupt
System
IEN0
CTCON 2)
CT1CON 2)
IEN1 2)
IEN2 2)
IEN3
IP0 2)
IP1 2)
IRCON0
IRCON1
IRCON2 4)
EICC1 4)
TCON 2)
T2CON 2)
A8H1)
E1H
BCH
B8H 1)
9AH
BEH
A9H
B9H
C0H 1)
D1H
BFH
BFH
88H 1)
C8H 1)
00H
01000000B 3)
X1XX0000B 3)
00H
XX0000X0B 3)
XXXX00XXB 3)
00H
0X000000B 3)
00H
00H
00H
FFH
00H
00H
XRAM
XPAGE
Page Address Register for XRAM
SYSCON 2) System Control Register
91H
B1H
00H
1010XX01B 3)
A/D
Converter
ADCON0
ADCON1
ADDATH
ADDATL
D8H1)
DCH
D9H
DAH
00H
01000000B 3)
00H
00H
1)
2)
3)
4)
5)
6)
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
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
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
Symbol
Name
Address Contents after
Reset
Compare /
Capture
Unit (CCU)
Timer 2
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 )
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
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
5)
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
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
Symbol
Name
Address Contents after
Reset
Compare /
Capture
Unit (CCU)
Timer 2
cont’d
CAFR 5)
CRCH
CRCL
COMSETL
COMSETH
COMCLRL
COMCLRH
SETMSK
CLRMSK
CTCON 2)
CTRELH 5)
CTRELL 5)
CT1RELL 5)
TH2
TL2
T2CON 2)
CT1CON 2)
PRSC 2)
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
F7H
CBH
CAH
A1H
A2H
A3H
A4H
A5H
A6H
E1H
DFH
DEH
DFH
DEH
CDH
CCH
C8H 1)
BCH
B4H
00H
00H
00H
00H
00H
00H
00H
00H
00H
01000000B 3)
00H
00H
00H
00H
00H
00H
00H
X1XX0000B 3)
11010101B 3)
Serial
Channels
ADCON0 2)
PCON 2)
S0BUF
S0CON
S0RELL
S0RELH
S1BUF
S1CON
S1RELL
S1RELH
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
D8H 1)
87H
99H
98H 1)
AAH
BAH
9CH
9BH
9DH
BBH
00H
00H
XXH 3)
00H
D9H
XXXXXX11B 3)
XXH 3)
01000000B 3)
00H
XXXXXX11B 3)
Watchdog
IEN0 2)
IEN1 2)
IP0 2)
IP1 2)
WDTREL
WDTL 6)
WDTH 6)
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
A8H 1)
B8H 1)
A9H
B9H
86H
84H
85H
00H
00H
00H
0X000000B 3)
00H
00H
00H
CT1RELH 5)
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
Symbol
Name
Address Contents after
Reset
MUL/DIV
Unit
ARCON
MD0
MD1
MD2
MD3
MD4
MD5
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
EFH
E9H
EAH
EBH
ECH
EDH
EEH
0XXXXXXXB 3)
XXH 3)
XXH 3)
XXH 3)
XXH 3)
XXH 3)
XXH 3)
Timer 0 /
Timer 1
TCON
TH0
TH1
TL0
TL1
TMOD
PRSC 2)
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
88H 1)
8CH
8DH
8AH
8BH
89H
B4H
00H
00H
00H
00H
00H
00H
11010101B 3)
Ports
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)
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
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
FFH
FFH
FFH
FFH
FFH
FFH
FFH
FFH
FFH
FFH
FFH
FFH
FFH
FFH
--FFH
FFH
Power
Saving
Modes
PCON
Power Control Register
87H
00H
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)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mapped
by 2)
80H
P0
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=0
80H
DIR0
FFH
FFH
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=1
81H
SP
07H
.7
.6
.5
.4
.3
.2
.1
.0
–
82H
83H
DPL
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
DPH
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
84H
WDTL
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
85H
86H
WDTH
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
WDTREL
00H
WPSEL
.6
.5
.4
.3
.2
.1
.0
–
87H
88H
PCON
00H
SMOD
PDS
IDLS
SD
GF1
GF0
PDE
IDLE
–
TCON
00H
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
–
89H
8AH
TMOD
00H
GATE
C/T
M1
M0
GATE
C/T
M1
M0
–
TL0
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
8BH
8CH
TL1
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
TH0
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
8DH
TH1
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
90H
P1
FFH
T2
CLKOUT
T2EX
INT2
INT6
INT5
INT4
INT3
PDIR=0
90H
DIR1
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=1
91H
XPAGE
FFH
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
92H
DPSEL
–
–
–
–
–
.2
.1
.0
–
98H
S0CON
XXXX.
X000B
00H
SM0
SM1
SM20
REN0
TB80
RB80
TI0
RI0
–
99H
9AH
S0BUF
XXH
.7
.6
.5
.4
.3
.2
.1
.0
–
IEN2
–
–
ECR
ECS
ECT
ECMP
–
ES1
–
9BH
S1CON
XX00.
00X0B
0100.
0000B
SM
S1P
SM21
REN1
TB81
RB81
TI1
RI1
–
9CH
S1BUF
XXH
.7
.6
.5
.4
.3
.2
.1
.0
–
9DH
S1RELL
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
A0H
P2
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=0
A0H
DIR2
FFH
FFH
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=1
.2
.1
.0
–
A1H
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
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mapped
by 2)
.7
.6
.5
.4
.3
.2
.1
.0
–
.7
.6
.5
.4
.3
.2
.1
.0
–
.7
.6
.5
.4
.3
.2
.1
.0
–
A5H
COMCLRH 00H
SETMSK
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
A6H
CLRMSK
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
A8H
IEN0
00H
EAL
WDT
ET2
ES0
ET1
EX1
ET0
EX0
–
A9H
AAH
IP0
00H
OWDS WDTS
.5
.4
.3
.2
.1
.0
–
S0RELL
D9H
.7
.6
.5
.4
.3
.2
.1
.0
–
B0H
P3
RD
WR
T1
T0
INT1
INT0
TxD0
RxD0
PDIR=0
B0H
DIR3
FFH
FFH
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=1
B1H
SYSCON
1010.
XX01B
SYSCON1 00XX.
3)
XEE0B
CLKP
PMOD
1
RMAP
–
–
XMAP1 XMAP0 –
ESWC
SWC
–
EA1
EA0
PRGEN1 PRGEN0 SWAP
–
B4H
PRSC
1101.
0101B
WDTP
S0P
T2P1
T2P0
T1P1
T1P0
T0P1
T0P0
–
B8H
IEN1
00H
EXEN2 SWDT
EX6
EX5
EX4
EX3
EX2
EADC
–
B9H
IP1
PDIR
–
.5
.4
.3
.2
.1
.0
–
BAH
S0RELH
0X00.
0000B
XXXX.
XX11B
–
–
–
–
–
–
.1
.0
–
BBH
S1RELH
XXXX.
XX11B
–
–
–
–
–
–
.1
.0
–
BCH
CT1CON
X1XX.
0000B
–
CT1P
–
–
CT1F
CLK12 CLK11 CLK10 –
BEH
IEN3
XXXX.
00XXB
–
–
–
–
ECT1
ECC1
–
–
–
BFH
IRCON2
00H
ICC17
ICC16
ICC15
ICC14
ICC13
ICC12
ICC11
ICC10
PDIR=0
BFH
C0H
EICC1
FFH
EICC17
EICC16
EICC15
EICC14
EICC13
EICC12
EICC11
EICC10
PDIR=1
IRCON0
00H
EXF2
TF2
IEX6
IEX5
IEX4
IEX3
IEX2
IADC
–
C1H
CCEN
00H
COCAH
3
COCAL3 COCAH
2
A2H
A3H
A4H
B2H
Content Bit 7
after
Reset 1)
COMSETH 00H
COMCLRL 00H
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)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mapped
by 2)
C2H
CCL1
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
C3H
CCH1
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
C4H
CCL2
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
C5H
CCH2
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
C6H
CCL3
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
C7H
CCH3
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
C8H
T2CON
00H
T2PS
I3FR
I2FR
T2R1
T2R0
T2CM
T2I1
T2I0
–
C9H
CC4EN
00H
COCAH
4
COCAL
4
COMO
–
CAH
CBH
CRCL
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
CRCH
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
CCH
TL2
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
CDH
TH2
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
CEH
CCL4
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
CFH
D0H
CCH4
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
PSW
00H
CY
AC
F0
RS1
RS0
OV
F1
P
–
D1H
D2H
IRCON1
00H
ICMP7 ICMP6 ICMP5 ICMP4 ICMP3 ICMP2 ICMP1 ICMP0 –
CML0
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
D2H
CC1L0
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
D3H
CMH0
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
D3H
CC1H0
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
D4H
CML1
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
D4H
CC1L1
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
D5H
CMH1
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
D5H
CC1H1
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
D6H
CML2
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
D6H
CC1L2
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
D7H
CMH2
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
D7H
CC1H2
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
D8H
ADCON0
00H
BD
CLK
ADEX
BSY
ADM
MX2
MX1
MX0
–
D9H
ADDATH
00H
.7
(MSB)
.6
.5
.4
.3
.2
.1
.0
–
COCO
EN1
COCO
N2
COCO
N1
COCO
N0
COCO
EN0
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)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mapped
by 2)
DAH
ADDATL
00H
.7
.6
(LSB)
–
–
–
–
–
–
–
DBH
DCH
P7
–
.7
.6
.5
.4
.3
.2
.1
.0
–
ADCON1
0100.
0000B
ADCL1 ADCL0 ADST1 ADST0 MX3
MX2
MX1
MX0
–
DDH
P8
–
–
.6
.5
.4
.3
.2
.1
.0
–
DEH
CTRELL
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
DEH
CT1RELL
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
DFH
DFH
CTRELH
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
CT1RELH
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
E0H
ACC
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
E1H
CTCON
0100.
0000B
T2PS1 CTP
ICR
ICS
CTF
CLK2
CLK1
CLK0
–
E2H
CML3
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
E2H
CC1L3
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
E3H
CMH3
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
E3H
CC1H3
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
E4H
CML4
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
E4H
CC1L4
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
E5H
CMH4
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
E5H
CC1H4
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
E6H
CML5
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
E6H
CC1L5
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
E7H
CMH5
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
E7H
CC1H5
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
E8H
P4
CM7
CM6
CM5
CM4
CM3
CM2
CM1
CM0
PDIR=0
E8H
DIR4
FFH
FFH
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=1
E9H
MD0
XXH
.7
.6
.5
.4
.3
.2
.1
.0
–
EAH
EBH
MD1
XXH
.7
.6
.5
.4
.3
.2
.1
.0
–
MD2
XXH
.7
.6
.5
.4
.3
.2
.1
.0
–
ECH
EDH
MD3
XXH
.7
.6
.5
.4
.3
.2
.1
.0
–
MD4
XXH
.7
.6
.5
.4
.3
.2
.1
.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
3-26
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)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mapped
by 2)
EEH
EFH
MD5
XXH
.7
.6
.5
.4
.3
.2
.1
.0
–
ARCON
0XXX.
XXXXB
MDEF
MDOV
SLR
SC.4
SC.3
SC.2
SC.1
SC.0
–
F0H
B
00H
.7
.6
.5
.4
.3
.2
.1
.0
–
F2H
F2H
CML6
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
CC1L6
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
F3H
CMH6
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
F3H
CC1H6
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
F4H
CML7
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
F4H
CC1L7
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
F5H
CMH7
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
F5H
CC1H7
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
F6H
CMEN
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
F6H
CC1EN
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
F7H
CMSEL
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=0
F7H
CAFR
00H
.7
.6
.5
.4
.3
.2
.1
.0
RMAP=1
F8H
P5
CCM7
CCM6
CCM5
CCM4
CCM3
CCM2
CCM1
CCM0
PDIR=0
F8H
DIR5
FFH
FFH
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=1
F9H
P9
FFH
CC17
CC16
CC15
CC14
CC13
CC12
CC11
CC10
PDIR=0
F9H
DIR9
FFH
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=1
FAH
FAH
P6
FFH
.7
.6.
.5
.4
.3
TxD1
RxD1
ADST
PDIR=0
DIR6
FFH
.7
.6
.5
.4
.3
.2
.1
.0
PDIR=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
3-27
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
4-2
1997-10-01
External Bus Interface
C509-L
a)
One Machine Cycle
S1
S2
S3
S4
S5
One Machine Cycle
S6
S1
S2
S3
S4
S5
S6
ALE
PSEN
(A)
without
MOVX
RD
PCH
OUT
P2
P0
PCL
OUT
INST.
IN
PCH
OUT
INST.
IN
PCL OUT
valid
b)
PCH
OUT
INST.
IN
PCL
OUT
PCL OUT
valid
S2
S3
S4
S5
INST.
IN
PCL
OUT
PCL OUT
valid
One Machine Cycle
S1
PCH
OUT
INST.
IN
PCL
OUT
PCL OUT
valid
One Machine Cycle
S6
S1
S2
S3
S4
S5
S6
ALE
PSEN
(B)
with
MOVX
RD
PCH
OUT
P2
P0
PCL
OUT
INST.
IN
DPH OUT OR
P2 OUT
DATA
IN
INST.
IN
PCH
OUT
PCL
OUT
INST.
IN
MCT03220
PCL OUT
valid
DPL or Ri
valid
PCL OUT
valid
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
6
CLKP PMOD
Reset Value : 1010XX01B
5
4
3
2
1
RMAP
–
–
1
LSB
0
XMAP1 XMAP0
SYSCON
The functions of the shaded bits are not described in this section.
Bit
Function
Bit 5
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
RESET
EA
ALE
PSEN
SYSCON
PCON
TCON
C500
MCU
RSYSCON
RPCON
RTCON
EH-IC
Enhanced Hooks
Interface Circuit
Port 0
Port 2
Optional
I/O Ports
Port 3
Port 1
RPort 2 RPort 0
Target System Interface
TEA TALE TPSEN
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)
Reset Value : XXXXX000B
Bit No. MSB
7
6
5
4
3
2
1
LSB
0
92H
–
–
–
–
.2
.1
.0
–
DPSEL
Bit
Function
–
Reserved bits for future use.
DPSEL.2-0
Data pointer select bits
DPSEL.2-0 defines the number of the actual active data pointer.DPTR0-7.
Semiconductor Group
4-6
1997-10-01
External Bus Interface
C509-L
- - - - -
.2 .1 .0
DPSEL(92 H)
DPSEL
DPTR7
Selected
Data-
.2
.1
.0
pointer
0
0
0
DPTR 0
0
0
1
DPTR 1
0
1
0
DPTR 2
0
1
1
DPTR 3
1
0
0
DPTR 4
1
0
1
DPTR 5
1
1
0
DPTR 6
1
1
1
DPTR 7
DPTR0
DPH(83 H )
DPL(82 H)
External Data Memory
MCD00779
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:
Semiconductor Group
1FFFH
2FA0H
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
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
MOVX
MOV
MOV
POP
POP
@DPTR, A
LOW(DES_PTR), DPL
HIGH(DES_PTR),DPH
DPH
DPL
;
Semiconductor Group
;
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):
4-8
28
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
DPSEL
DPSEL, #06H
DPTR
…
A,@DPTR
DPSEL, #07H
MOVX
POP
@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
6
CLKP PMOD
Reset Value : 1010XX01B
5
4
3
2
1
RMAP
–
–
1
LSB
0
XMAP1 XMAP0
SYSCON
The functions of the shaded bits are not described in this section.
Bit
Function
–
Reserved bits for future use.
XMAP1
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.
XMAP0
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.
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)
Reset Value : 00H
Bit No. MSB
7
6
5
4
3
2
1
LSB
0
91H
.6
.5
.4
.3
.2
.1
.0
.7
XPAGE
Bit
Function
XPAGE.7-0
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
Address/Data
Port 0
XRAM
XPAGE
Write to Port 2
Page Address
Port 2
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
Address/Data
Port 0
XRAM
XPAGE
Write to XPAGE
Address/
I/O-Data
Port 2
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
Address/Data
Port 0
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
Semiconductor Group
;
; P2 shows AAH
; P2 still shows AAH but XRAM is addressed
; the contents of XRAM at F830H is moved to accumulator
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:
The upper address byte must be written to XPAGE or P2;
both writes select the XRAM address range.
b) Access to external memory:
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
1997-10-01
Semiconductor Group
MOVX
@DPTR
4-17
MOVX
@ Ri
EA = 0
EA = 1
XMAP1, XMAP0
XMAP1, XMAP0
00
10
X1
00
10
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
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
b)RD/WR active
c)ext.memory
is used
a)P0/P2→Bus
b)RD/WR active
c)ext.memory
is used
DPTR
≥
XRAM
address
range
a)P0/P2→Bus
(WR / RD Data)
b)RD/WR
inactive
c)XRAM 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/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
XPAGE
<
XRAM
addr.page
range
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
XPAGE
≥
XRAM
addr.page
range
a)P0→Bus
(WR / RD Data)
P2→I/O
b)RD/WR
inactive
c)XRAM 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
DPTR
<
XRAM
address
range
Table 4-1
Behaviour of P0/P2 and RD/WR During MOVX Accesses
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
(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
1997-10-01
modes compatible to 8051/C501 family
a)P0→Bus
P2→I/O
b)RD/WR active
c)ext.memory
is used
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
5-5
Phase
RESET
VCC
RC
Oscillator
On-Chip
Oscillator
Ports
II
Clock from RC-Oscillator, Reset at Ports
Power On;
undef. Port
typ. 18 µs
max. 34 µs
Reset
I
Undef.
IV
Port remains
in reset
because of
ext. reset
signal
III
On-chip oscillator
starts; final reset
sequence by
oscillator WD;
max. 768 Cycles
MCD02722
Start of
program
execution
V
Reset / System Clock
C509-L
Figure 5-3
Power-On Reset of the 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)
Bit No.
D8H
B1H
Reset Value : 00H
Reset Value : 1010XX01B
MSB
DFH
DEH
DDH
DCH
DBH
DAH
D9H
LSB
D8H
BD
CLK
ADEX
BSY
ADM
MX2
MX1
MX0
7
6
5
4
3
2
1
0
RMAP
–
–
CLKP PMOD EALE
XMAP1 XMAP0
ADCON0
SYSCON
These bits are not used in controlling the clock output function.
Bit
Function
CLK
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.
CLKP
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)
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
Parallel I/O
6.1.1
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)
Bit No.
B1H
B9H
MSB
7
6
CLKP PMOD
Reset Value : 1010XX01B
Reset Value : 0X000000B
5
4
3
2
1
RMAP
–
–
1
LSB
0
XMAP1 XMAP0
7
6
5
4
3
2
1
0
PDIR
–
.5
.4
.3
.2
.1
.0
SYSCON
IP1
The shaded bits are not used for port selection.
Bit
Function
PMOD
Port mode selection
PMOD = 0: Quasi-bidirectional port structure is selected (reset value)
PMOD = 1: Bidirectional port structure is selected.
PDIR
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.
Direction Registers DIR0-DIR6, DIR9 (Mapped Address = Port Address)
Bit No.
Address. =
Port-Addr.
Reset Value : FFH
MSB
7
6
5
4
3
2
1
LSB
0
.7
.6
.5
.4
.3
.2
.1
.0
Direction
Register
Bit
Function
Bit 7...0
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
Int. Bus
Write
to
Latch
Q
D
Bit
Latch
CLK
Q
Pin
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:
VCC
Delay = 1 State
=1
<_ 1
p1
p2
p3
Port
Pin
n1
Q
VSS
Input Data
(Read Pin)
=1
=1
MCS03230
Figure 6-4
Output Driver Circuit of Ports 1 to 6 and 9
– The pulldown FET n1 is of n-channel type. It is a very strong driver transistor which is capable
of sinking high currents (IOL); it is only activated if a “0” is programmed to the port pin. A short
circuit to VCC must be avoided if the transistor is turned on, since the high current might destroy
the FET. This also means that no “0” must be programmed into the latch of a pin that is used
as input.
– The pullup FET p1 is of p-channel type. It is activated for one state (S1) if a 0-to-1 transition
is programmed to the port pin, i.e. a “1” is programmed to the port latch which contained a “0”.
The extra pullup can drive a similar current as the pulldown FET n1. This provides a fast
transition of the logic levels at the pin.
– The pullup FET p2 is of p-channel type. It is always activated when a “1” is in the port latch,
thus providing the logic high output level. This pullup FET sources a much lower current than
p1; therefore the pin may also be tied to ground, e.g. when used as input with logic low input
level.
– The pullup FET p3 is of p-channel type. It is only activated if the voltage at the port pin is
higher than approximately 1.0 to 1.5 V. This provides an additional pullup current if a logic
high level shall be output at the pin (and the voltage is not forced lower than approximately
1.0 to 1.5 V). However, this transistor is turned off if the pin is driven to a logic low level, e.g
when used as input. In this configuration only the weak pullup FET p2 is active, which sources
the current IIL . If, in addition, the pullup FET p3 is activated, a higher current can be sourced
(ITL). Thus, an additional power consumption can be avoided if port pins are used as inputs
with a low level applied. However, the driving capability is stronger if a logic high level is
output.
Semiconductor Group
6-6
1997-10-01
On-Chip Peripheral Components
C509-L
The described activating and deactivating of the four different transistors results in four states which
can be:
– input low state (IL), p2 active only
– input high state (IH) = steady output high state (SOH), p2 and p3 active
– forced output high state (FOH), p1, p2 and p3 active
– output low state (OL), n1 active
If a pin is used as input and a low level is applied, it will be in IL state, if a high level is applied, it will
switch to IH state. If the latch is loaded with “0”, the pin will be in OL state. If the latch holds a “0”
and is loaded with “1”, the pin will enter FOH state for two cycles and then switch to SOH state. If
the latch holds a “1” and is reloaded with a “1” no state change will occur.
At the beginning of power-on reset the pins will be in IL state (latch is set to “1”, voltage level on pin
is below of the trip point of p3). Depending on the voltage level and load applied to the pin, it will
remain in this state or will switch to IH (=SOH) state.
If it is used as output, the weak pull-up p2 will pull the voltage level at the pin above p3’s trip point
after some time and p3 will turn on and provide a strong “1”. Note, however, that if the load exceeds
the drive capability of p2 (IIL), the pin might remain in the IL state and provide a week “1” until the
first 0-to-1 transition on the latch occurs. Until this the output level might stay below the trip point of
the external circuitry.
The same is true if a pin is used as bidirectional line and the external circuitry is switched from
output to input when the pin is held at “0” and the load then exceeds the p2 drive capabilities.
If the load exceeds IIL the pin can be forced to “1” by writing a “0” followed by a “1” to the port pin.
Semiconductor Group
6-7
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.1.2.2 Port 0 Circuitry
Port 0, in contrast to ports 1 to 6 and 9, is considered as “true” bidirectional, because the port 0 pins
float when configured as inputs. Thus, this port differs in not having internal pullups. The pullup FET
in the P0 output driver (see figure 6-5) is used only when the port is emitting 1 s during the external
memory accesses. Otherwise, the pullup is always off. Consequently, P0 lines that are used as
output port lines are open drain lines. Writing a “1” to the port latch leaves both output FETs off and
the pin floats. In that condition it can be used as high-impedance input. If port 0 is configured as
general I/O port and has to emit logic high-level (1), external pullups are required.
VCC
Addr./Data
Control
Read
Latch
&
=1
Int. Bus
Write to
Latch
D
Port
Pin
Q
Bit
Latch
CLK
MUX
Q
Read
Pin
MCS02434
Figure 6-5
Port 0 Circuitry
Semiconductor Group
6-8
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.1.2.3 Port 0 and Port 2 used as Address/Data Bus
As shown in figure 6-5 and below in figure 6-6, the output drivers of ports 0 and 2 can be switched
to an internal address or address/data bus for use in external memory accesses. In this application
they cannot be used as general purpose I/O, even if not all address lines are used externally. The
switching is done by an internal control signal dependent on the input level at the EA pin and/or the
contents of the program counter. If the ports are configured as an address/data bus, the port latches
are disconnected from the driver circuit. During this time, the P2 SFR remains unchanged while the
P0 SFR has 1’s written to it. Being an address/data bus, port 0 uses a pullup FET as shown in
figure 6-5. When a 16-bit address is used, port 2 uses the additional strong pullups p1 to emit 1’s
for the entire external memory cycle instead of the weak ones (p2 and p3) used during normal port
activity.
Addr.
Control
Read
Latch
VCC
Internal
Pull Up
Arrangement
Port
Pin
Int. Bus
Write to
Latch
D
Q
Bit
Latch
CLK
MUX
Q
=1
Read
Pin
MCS03228
Figure 6-6
Port 2 Circuitry
Semiconductor Group
6-9
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.1.3
Bidirectional (CMOS) Port Structure
6.1.1.3.1
Input Mode
Figure 6-7 shows the bidirectional port structure in the input mode.
Figure 6-7
Bidirectional Port Structure - Input Mode
The input mode for a port pin is selected by programming the corresponding direction bit to '1'
(QDL='1'). The FETs p1, p2, p3 and n1 are switched off. Through a Schmitt-Trigger, designed to
detect CMOS levels, the input signal is lead to the internal bus where it can be read by the
microcontroller.
Semiconductor Group
6-10
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.1.3.2
Output Mode
The output mode for a port pin is selected by programming the corresponding direction bit to '0'
(QDL='0'). The contents of the port latch determines whether a '1' (QPL='0') or a '0' (QPL='1') is
driven. Figure 6-8 shows the port structure in the output mode driving a '1' while figure 6-9
illustrates the port structure in the output mode driving a '0'.
Figure 6-8
Bidirectional Port Structure - Output Mode - “1”
The FET n1 is switched off. FET p1 is activated for one state (dashed lines) if a 0-to-1 transition is
programmed to the port pin, i.e. a '1' is programmed to the port latch which contained a '0'. The FETs
p2, p3 are both active and are driving the '1' at the port pin.
Semiconductor Group
6-11
1997-10-01
On-Chip Peripheral Components
C509-L
Figure 6-9
Bidirectional Port Structure - Output Mode - “0”
The FET n1 is switched on and is driving a '0' at the port pin. FETs p1, p2, p3 are switched off.
Semiconductor Group
6-12
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.1.3.3
Hardware Power Down Mode
Figure 6-10 shows the port structure when the HWPD-pin becomes active (HWPD='0'). First of all
the SFRs are written with their reset values. Therefore, the bit PMOD is cleared (PMOD=0), quasibidirectional port structure is enabled after leaving the hardware power down mode) and the port
latch and direction latch contain a '1' (QPL = '0', QDL='1'). Then the hardware power down mode
with ports in tri-state status is entered.
Figure 6-10
Bidirectional Port Structure - Hardware Power Down Mode
Due to HWPD='0' the FET n2 becomes active and the FETs p2 and p5 are switched off. The FETs
p1, p3 and n1 are switched off caused by the status of the port latch, direction latch and of PMOD
(reset values).
Semiconductor Group
6-13
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.2
Alternate Functions
Several pins of ports 1, 3, 4, 5 and 6 are multifunctional. They are port pins and also serve to
implement special features as listed in table 6-1.
Figure 6-11 shows a functional diagram of a port latch with alternate function. To pass the alternate
function to the output pin and vice versa, however, the gate between the latch and driver circuit must
be open. Thus, to use the alternate input or output functions, the corresponding bit latch in the port
SFR has to contain a one (1); otherwise the pull-down FET is on and the port pin is stuck at 0. (This
does not apply to ports 1.0 to 1.4 and ports 5.0 to 5.7 when operating in compare output mode).
After reset all port latches contain ones (1).
VCC
Alternate
Output
Function
Read
Latch
Internal
Pull Up
Arrangement
Pin
Int. Bus
Q
D
Bit
Latch
Write
to
Latch
CLK
&
Q
MCS01827
Read
Pin
Alternate
Input
Function
Figure 6-11
Circuitry of Ports 1, 3, 4, 5 and 6.0 through 6.2
Ports 6.3 through 6.7 have no alternate functions as described above. Therefore, the port circuitry
can do without the switching capability between alternate function and normal I/O operation. This
more simple circuitry is shown as basic port structure in figure 6-3.
Table 6-1 :
Alternate Functions of Port Pins
Port
Pin
Alternate Function
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
INT3/CC0
INT4/CC1
INT5/CC2
INT6/CC3
INT2/CC4
T2EX
CLKOUT
T2
External interrupt 3/capture 0/compare 0
External interrupt 4/capture 1/compare 1
External interrupt 5/capture 2/compare 2
External interrupt 6/capture 3/compare 3
External interrupt 2/capture 4/compare 4
Timer 2 ext. reload trigger input
System clock output
Timer 2 external count input
Semiconductor Group
6-14
1997-10-01
On-Chip Peripheral Components
C509-L
Table 6-1 :
Alternate Functions of Port Pins (cont’d)
Port
Pin
Alternate Function
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
RXD0
TXD0
INT0
INT1
T0
T1
WR
RD
Serial input channel 0
Serial output channel 0
External interrupt 0
External interrupt 1
Timer 0 external count input
Timer 1 external count input
External data memory write strobe
External data memory read strobe
P4.0
P4.1
P4.2
P4.3
P4.4
P4.5
P4.6
P4.7
CM0
CM1
CM2
CM3
CM4
CM5
CM6
CM7
Compare output for the CM0 register
Compare output for the CM1 register
Compare output for the CM2 register
Compare output for the CM3 register
Compare output for the CM4 register
Compare output for the CM5 register
Compare output for the CM6 register
Compare output for the CM7 register
P5.0
P5.1
P5.2
P5.3
P5.4
P5.5
P5.6
P5.7
CCM0
CCM1
CCM2
CCM3
CCM4
CCM5
CCM6
CCM7
Concurrent compare 0 output
Concurrent compare 1 output
Concurrent compare 2 output
Concurrent compare 3 output
Concurrent compare 4 output
Concurrent compare 5 output
Concurrent compare 6 output
Concurrent compare 7 output
P6.0
P6.1
P6.2
P6.3
ADST
RXD1
TXD1
WRF
External A/D converter start
Serial input channel 1
Serial output channel 1
Write external FLASH
P9.0
P9.1
P9.2
P9.3
P9.4
P9.5
P9.6
P9.7
CC10
CC11
CC12
CC13
CC14
CC15
CC16
CC17
Compare output/capture input for CC10 register
Compare output/capture input for CC11 register
Compare output/capture input for CC12 register
Compare output/capture input for CC13 register
Compare output/capture input for CC14 register
Compare output/capture input for CC15 register
Compare output/capture input for CC16 register
Compare output/capture input for CC17 register
Semiconductor Group
6-15
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.3
Port Handling
6.1.3.1 Port Timing
When executing an instruction that changes the value of a port latch, the new value arrives at the
latch during S6P2 of the final cycle of the instruction. However, port latches are only sampled by
their output buffers during phase 1 of any clock period (during phase 2 the output buffer holds the
value it noticed during the previous phase 1). Consequently, the new value in the port latch will not
appear at the output pin until the next phase 1, which will be at S1P1 of the next machine cycle.
When an instruction reads a value from a port pin (e.g. MOV A, P1) the port pin is actually sampled
in state 5 phase 1 or phase 2 depending on port and alternate functions. Figure 6-12 illustrates this
port timing. lt must be noted that this mechanism of sampling once per machine cycle is also used
if a port pin is to detect an “edge”, e.g. when used as counter input. In this case an “edge” is detected
when the sampled value differs from the value that was sampled the cycle before. Therefore, there
must be met certain requirements on the pulse length of signals in order to avoid signal “edges” not
being detected. The minimum time period of high and low level is one machine cycle, which
guarantees that this logic level is noticed by the port at least once.
S4
S5
S6
S1
S2
S3
P1 P2
P1 P2
P1 P2
P1 P2
P1 P2
P1 P2
XTAL2
Input sampled:
e.g.: MOV A, P1
p1 active for 1 state
(driver transistor)
or
Port
Old Data
New Data
Figure 6-12
Port Timing
Semiconductor Group
6-16
1997-10-01
On-Chip Peripheral Components
C509-L
6.1.3.2 Port Loading and Interfacing
The output buffers of ports 1 to 6 and 9 can drive TTL inputs directly. The maximum port load which
still guarantees correct logic output levels can be looked up in the C509-L DC characteristics in
chapter 11 or in the data sheet. The corresponding parameters are VOL and VOH.
The same applies to port 0 output buffers. They do, however, require external pullups to drive
floating inputs, except when being used as the address/data bus.
When used as inputs it must be noted that the ports 1 to 6 and 9 are not floating but have internal
pullup transistors. The driving devices must be capable of sinking a sufficient current if a logic low
level shall be applied to the port pin (the parameters ITL and IIL in the C509-L DC characteristics
specify these currents). Port 0 has floating inputs when used for digital input.
6.1.3.3
Read-Modify-Write Feature of Ports 1 to 6 and 9
Some port-reading instructions read the latch and others read the pin. The instructions reading the
latch rather than the pin read a value, possibly change it, and then rewrite it to the latch. These are
called “read-modify-write”- instructions, which are listed in table 6-2. If the destination is a port or a
port pin, these instructions read the latch rather than the pin. Note that all other instructions which
can be used to read a port, exclusively read the port pin. In any case, reading from latch or pin,
resp., is performed by reading the SFRs P0, P1, P2 and P3; for example, “MOV A, P3” reads the
value from port 3 pins, while “ANL P3, #0AAH” reads from the latch, modifies the value and writes
it back to the latch.
It is not obvious that the last three instructions in table 6-2 are read-modify-write instructions, but
they are. The reason is that they read the port byte, all 8 bits, modify the addressed bit, then write
the complete byte back to the latch.
Table 6-2 : “Read-Modify-Write”- Instructions
Instruction
Function
ANL
Logic AND; e.g. ANL P1, A
ORL
Logic OR; e.g. ORL P2, A
XRL
Logic exclusive OR; e.g. XRL P3, A
JBC
Jump if bit is set and clear bit; e.g. JBC P1.1, LABEL
CPL
Complement bit; e.g. CPL P3.0
INC
Increment byte; e.g. INC P1
DEC
Decrement byte; e.g. DEC P1
DJNZ
Decrement and jump if not zero; e.g. DJNZ P3, LABEL
MOV Px.y,C
Move carry bit to bit y of port x
CLR Px.y
Clear bit y of port x
SETB Px.y
Set bit y of port x
Semiconductor Group
6-17
1997-10-01
On-Chip Peripheral Components
C509-L
The reason why read-modify-write instructions are directed to the latch rather than the pin is to avoid
a possible misinterpretation of the voltage level at the pin. For example, a port bit might be used to
drive the base of a transistor. When a “1” is written to the bit, the transistor is turned on. If the CPU
then reads the same port bit at the pin rather than the latch, it will read the base voltage of the
transistor (approx. 0.7 V, i.e. a logic low level!) and interpret it as “0”. For example, when modifying
a port bit by a SETB or CLR instruction, another bit in this port with the above mentioned
configuration might be changed if the value read from the pin were written back to the latch.
However, reading the latch rater than the pin will return the correct value of “1”.
Semiconductor Group
6-18
1997-10-01
On-Chip Peripheral Components
C509-L
6.2
Timer/Counter 0 and 1
The C509-L has a number of general purpose 16-bit timer/counters: timer 0, timer 1, timer 2 and
the compare timer (timer 2 and the compare timer are discussed separately in section 6.3
“Compare/Capture Unit”). Timer/counter 0 and 1 are fully compatible with timer/counters 0 and 1 of
the SAB 8051 and can be used in the same operating modes.
Timer/counter 0 and 1 which are discussed in this section can be configured to operate either as
timers or event counters:
– In “timer” function, the register is incremented at a maximum every machine cycle. Thus one
can think of it as counting machine cycles. Since a machine cycle consists of 6 oscillator
periods, the count rate is 1/6 of the oscillator frequency.
– In “counter” function, the register is incremented in response to a 1-to-0 transition (falling
edge) at its corresponding external input pin, T0 or T1 (alternate functions of P3.4 and P3.5,
resp.). In this function the external input is sampled during S5P2 of every machine cycle.
When the samples show a high in one cycle and a low in the next cycle, the count is
incremented. The new count value appears in the register during S3P1 of the cycle following
the one in which the transition was detected. Since it takes two machine cycles (12 oscillator
periods) to recognize a 1-to-0 transition, the maximum count rate is 1/12 of the oscillator
frequency. There are no restrictions on the duty cycle of the external input signal, but to
ensure that a given level is sampled at least once before it changes, it must be held for at least
one full machine cycle.
In addition to the “timer” and “counter” selection, timer/counters 0 and 1 have four operating modes
from which to select.
Semiconductor Group
6-19
1997-10-01
On-Chip Peripheral Components
C509-L
6.2.1
Timer/Counter 0 / 1 Registers
The Timer 0/1 unit of the C509-L is controlled by totally 8 special function registers: TCON, TMOD,
PRSC, IEN0, TL0, TH0, TL1, and TH1.
Each timer consists of two 8-bit registers (TH0 and TL0 for timer/counter 0, TH1 and TL1 for
timer/counter 1) which may be combined to one timer configuration depending on the mode that is
established. The functions of the timers are controlled by two special function registers TCON and
TMOD. The interrupt enable control bits are located in the SFR IEN0.
The upper four bits of the special function register TCON are the run and overflow flags for timer 0
and 1.
Special Function Register TCON (Address. 88H)
Special Function Register IEN0 (Address. A8H)
Bit No.
88H
MSB
8FH
TF1
8EH
TR1
AFH
A8H
EAL
AEH
WDT
8DH
TF0
ADH
ET2
8CH
TR0
ACH
ES0
8BH
IE1
ABH
ET1
Reset Value : 00H
Reset Value : 00H
8AH
89H
LSB
88H
IT1
IE0
IT0
AAH
A9H
A8H
EX1
ET0
EX0
TCON
IEN0
The shaded bits are not used for timer/counter 0 and 1.
Bit
Function
TF1
Timer 1 overflow flag
Set by hardware on timer/counter 1 overflow. Cleared by hardware when
processor vectors to interrupt routine.
TR1
Timer 1 run control bit.
Set/cleared by software to turn timer/counter 1 on/off.
TF0
Timer 0 overflow flag
Set by hardware on timer/counter 0 overflow. Cleared by hardware when
processor vectors to interrupt routine.
TR0
Timer 0 run control bit.
Set/cleared by software to turn timer/counter 0 on/off.
ET1
Timer 1 overflow interrupt enable.
If ET1 = 0, the timer 1 interrupt is disabled.
ET0
Timer 0 overflow interrupt enable.
If ET0 = 0, the timer 0 interrupt is disabled.
Semiconductor Group
6-20
1997-10-01
On-Chip Peripheral Components
C509-L
Special function register TMOD is used for mode select, gating, and counter/timer select purposes.
The lower 4 bits control timer 0 and the upper 4 bits control timer 1.
Special Function Register TMOD (Address. 89H)
Bit No.
89H
Reset Value : 00H
MSB
7
6
5
4
3
2
1
LSB
0
GATE
C/T
M1
M0
GATE
C/T
M1
M0
Timer 1 Control
TMOD
Timer 0 Control
Bit
Function
GATE
Gating control
When set, timer/counter “x” is enabled only while “INT x” pin is high and “TRx”
control bit is set.
When cleared timer “x” is enabled whenever “TRx” control bit is set.
C/T
Counter or timer select bit
Set for counter operation (input from “Tx” input pin).
Cleared for timer operation (input from internal system clock).
M1
M0
Operating mode select bits
M1
M0
Operating mode
0
0
8-bit timer/counter
0
1
16-bit timer/counter
1
0
8-bit auto-reload timer/counter
1
1
Timer 0 : TL0 is an 8-bit timer/counter controlled by the
standard timer 0 control bits. TH0 is an 8-bit timer
only controlled by timer 1 control bits.
Timer 1 : Timer/counter 1 stops
Semiconductor Group
6-21
1997-10-01
On-Chip Peripheral Components
C509-L
The 4 lower bits of special function register PRSC control the timer 0/1 input clock prescaler
operation.
Special Function Register PRSC (Address B4H)
Bit No.
B4H
Reset Value : 11010101B
MSB
7
6
5
4
3
2
1
LSB
0
WDTP
S0P
T2P1
T2P0
T1P1
T1P0
T0P1
T0P0
Timer 1 Control
PRSC
Timer 0 Control
The shaded bits are not used for timer/counter 0 and 1.
Bit
Function
T1P1
T1P0
Prescaler select bits for timer 1
T0P1
T0P0
T1P1
T1P0
Divider Ratio
0
0
1:1
0
1
1 : 2 (reset value)
1
0
1:4
1
1
1:8
Prescaler select bits for timer 0
T0P1
T0P0
Divider Ratio
0
0
1:1
0
1
1 : 2 (reset value)
1
0
1:4
1
1
1:8
Semiconductor Group
6-22
1997-10-01
On-Chip Peripheral Components
C509-L
The 4 registers TL0, TH0, TL1, and TH1 are the count/reload registers of the timer 0 and 1:
Special Function Registers TL0/TH0 (Addresses 8AH/8CH)
Special Function Registers TL1/TH1 (Addresses 8BH/8DH)
Reset Value : 00H
Reset Value : 00H
Bit No. MSB
7
6
5
4
3
2
1
LSB
0
8AH
.7
.6
.5
.4
.3
.2
.1
.0
TL0
8CH
.7
.6
.5
.4
.3
.2
.1
.0
TH0
8BH
.7
.6
.5
.4
.3
.2
.1
.0
TL1
8DH
.7
.6
.5
.4
.3
.2
.1
.0
TH1
Bit
Function
TL0.7 - 0
Timer 0 low byte
The TL0 is the 8-bit low byte count register of timer 0.
TH0.7 - 0
Timer 0 high byte
The TH0 is the 8-bit high byte count/reload register of timer 0.
TL1.7 - 0
Timer 1 low byte
The TL1 is the 8-bit low byte count register of timer 1.
TH1.7 - 0
Timer 1 high byte
The TH1 is the 8-bit high byte count/reload register of timer 1.
In the following sections the symbols TH0 and TL0 are used to specify the high-byte and low-byte
of timer 0 (TH1 and TL1 for timer 1, respectively). The operating modes are described and shown
for timer 0. If not explicitly noted, the operating modes are also valid for timer 1.
Semiconductor Group
6-23
1997-10-01
On-Chip Peripheral Components
C509-L
6.2.2
Mode 0
Putting either timer/counter 0/1 into mode 0 configures it as an 8-bit timer/counter with a
divide-by-32 prescaler. Figure 6-13 shows the mode 0 operation.
In this mode, the timer register is configured as a 13-bit register. As the count rolls over from all 1’s
to all 0’s, it sets the timer overflow flag TF0. The overflow flag TF0 then can be used to request an
interrupt (see section 8 for details about the interrupt structure). The counted input is enabled to the
timer when TR0 = 1 and either GATE = 0 or INT0 = 1 (setting GATE = 1 allows the timer to be
controlled by external input INT0, to facilitate pulse width measurements). TR0 is a control bit in the
special function register TCON; GATE is in TMOD.
The 13-bit register consists of all 8 bits of TH0 and the lower 5 bits of TL0. The upper 3 bits of TL0
are indeterminate and should be ignored. Setting the run flag (TR0) does not clear the registers.
Mode 0 operation is the same for timer 0 as for timer 1. Substitute T0P1, T0P0, TR0, TF0, TH0,
TL0, T0 and INT0 with the corresponding timer 1 signals in figure 6-13.
Figure 6-13
Timer/Counter 0/1, Mode 0: 13 Bit Timer/Counter
Semiconductor Group
6-24
1997-10-01
On-Chip Peripheral Components
C509-L
6.2.3
Mode 1
Mode 1 is the same as mode 0, except that the timer register runs with all 16 bits. Mode 1 is shown
in figure 6-14.
Figure 6-14
Timer/Counter 0/1, Mode 1: 16-Bit Timer/Counter
Semiconductor Group
6-25
1997-10-01
On-Chip Peripheral Components
C509-L
6.2.4
Mode 2
Mode 2 configures the timer register as an 8-bit counter (TL0) with automatic reload, as shown in
figure 6-15. Overflow from TL0 not only sets TF0, but also reloads TL0 with the contents of TH0,
which is preset by software. The reload leaves TH0 unchanged.
Figure 6-15
Timer/Counter 0/1, Mode 2: 8-Bit Timer/Counter with Auto-Reload
Semiconductor Group
6-26
1997-10-01
On-Chip Peripheral Components
C509-L
6.2.5
Mode 3
Mode 3 has different effects on timer 0 and timer 1. Timer 1 in mode 3 simply holds its count. The
effect is the same as setting TR1 = 0. Timer 0 in mode 3 establishes TL0 and TH0 as two separate
counters. The logic for mode 3 on timer 0 is shown in figure 6-16. TL0 uses the timer 0 control bits:
C/T, GATE, TR0, INT0, and TF0. TH0 is locked into a timer function and takes over the use of TR1
and TF1 from timer 1. Thus, TH0 now controls the “timer 1” interrupt.
Mode 3 is provided for applications requiring an extra 8-bit timer or counter. When timer 0 is in
mode 3, timer 1 can be turned on and off by switching it out of and into its own mode 3, or can still
be used by the serial channel as a baud rate generator, or in fact, in any application not requiring
an interrupt from timer 1 itself.
Figure 6-16
Timer/Counter 0, Mode 3: Two 8-Bit Timer/Counter
Semiconductor Group
6-27
1997-10-01
On-Chip Peripheral Components
C509-L
6.3
The Compare/Capture Unit (CCU)
The compare/capture unit is one of the C509-L’s most powerful peripheral units for use in all kinds
of digital signal generation and event capturing like pulse generation, pulse width modulation, pulse
width measuring etc.
The CCU consists of three 16-bit timer/counters with automatic reload feature and an array of 13
compare or compare/capture registers. A set of six control registers is used for flexible adapting of
the CCU to a wide variety of user’s applications.
The CCU is the ideal peripheral unit for various automotive control applications (ignition/injection
control, anti-lock brakes, etc.) as well as for industrial applications (DC, three-phase AC, and
stepper motor control, frequency generation, digital-to-analog conversion, process control, etc.)
The detailed description in the following sections refers to the CCU’s functional blocks as listed
below:
– Timer 2 with fOSC/6 input clock, 4-bit prescaler, 16-bit reload, counter/gated timer mode and
overflow interrupt request.
– Compare timers with fOSC input clock, 4-bit prescaler, 16-bit reload and overflow interrupt
request.
– Compare/(reload/)capture register array consisting of four different kinds of registers:
one 16-bit compare/reload/capture register,
three 16-bit compare/capture registers,
one 16-bit compare/capture register with additional "concurrent compare" feature,
eight 16-bit compare registers with timer-overflow controlled loading.
In summary, the register array may control up to 29 output lines and can request up to 11
independent interrupts.
In the following text all double-byte compare, compare/capture or compare/reload/capture registers
are called CMx (x = 0 … 7), CCx (x = 0 … 4) or CRC register, respectively.
The block diagram in figure 6-17 shows the general configuration of the CCU. All CC1 to CC4
registers and the CRC register are exclusively assigned to timer 2. Each of the eight compare
registers CM0 through CM7 can either be assigned to timer 2 or to the faster compare timer, e.g. to
provide up to 8 PWM output channels. The assignment of the CMx registers - which can be done
individually for every single register - is combined with an automatic selection of one of the two
possible compare modes. The compare/capture registers CC10 to CC17 and the reload register
CT1REL are assigned to compare timer 1 and are mapped to the corresponding registers of the
compare timer.
Port 4, port 5, port 9 and five lines of port 1 have alternate functions dedicated to the CCU. These
functions are listed in table 6-3. Normally each register controls one dedicated output line at the
ports. Register CC4 is an exception as it can manipulate up to nine output lines (one at port 1.4 and
the other eight at port 5) concurrently. This function is referenced as "concurrent compare".
Note that for an alternate input function the port latch has to be programmed with a ’1’. For bit
latches of port pins that are used as compare outputs, the value to be written to the bit latches
depends on the compare mode established.
A list of all special function registers concerned with the CCU is given in table 6-4.
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
Figure 6-17
Block Diagram of the CCU
Semiconductor Group
6-29
1997-10-01
On-Chip Peripheral Components
C509-L
Table 6-3
Alternate Port Functions of the CCU
Pin Symbol
Pin No.
Alternate Function
P1.0/INT3/CC0
P1.1/INT4/CC1
P1.2/INT5/CC2
P1.3/INT6/CC3
P1.4/INT2/CC4
P1.5/T2EX
P1.7/T2
9
8
7
6
1
100
98
Compare output/capture input for CRC register
Compare output/capture input for CC1 register
Compare output/capture input for CC2 register
Compare output/capture input for CC3 register
Compare output/capture input for CC4 register
Timer 2 external reload trigger input
Timer 2 external count input
P4.0/CM0
P4.1/CM1
P4.2/CM2
P4.3/CM3
P4.4/CM4
P4.5/CM5
P4.6/CM6
P4.7/CM7
64
65
66
68
69
70
71
72
Compare output for the CM0 register
Compare output for the CM1 register
Compare output for the CM2 register
Compare output for the CM3 register
Compare output for the CM4 register
Compare output for the CM5 register
Compare output for the CM6 register
Compare output for the CM7 register
P5.0/CCM0
P5.1/CCM1
P5.2/CCM2
P5.3/CCM3
P5.4/CCM4
P5.5/CCM5
P5.6/CCM6
P5.7/CCM7
44
43
42
41
40
39
38
37
Concurrent compare 0 output
Concurrent compare 1 output
Concurrent compare 2 output
Concurrent compare 3 output
Concurrent compare 4 output
Concurrent compare 5 output
Concurrent compare 6 output
Concurrent compare 7 output
P9.0/CC10
P9.1/CC11
P9.2/CC12
P9.3/CC13
P9.4/CC14
P9.5/CC15
P9.6/CC16
P9.7/CC17
74
75
76
77
5
4
3
2
Compare output/capture input for CC10 register
Compare output/capture input for CC11 register
Compare output/capture input for CC12 register
Compare output/capture input for CC13 register
Compare output/capture input for CC14 register
Compare output/capture input for CC15 register
Compare output/capture input for CC16 register
Compare output/capture input for CC17 register
Semiconductor Group
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On-Chip Peripheral Components
C509-L
Table 6-4
Special Function Register of the CCU
Symbol
CCEN
CC4EN
CCH1
CCH2
CCH3
CCH4
CCL1
CCL2
CCL3
CCL4
CMEN
CMH0
CMH1
CMH2
CMH3
CMH4
CMH5
CMH6
CMH7
CML0
CML1
CML2
CML3
CML4
CML5
CML6
CML7
CC1EN
CC1H0
CC1H1
CC1H2
CC1H3
CC1H4
CC1H5
CC1H6
CC1H7
CC1L0
CC1L1
CC1L2
CC1L3
CC1L4
CC1L5
CC1L6
CC1L7
Description
Address with
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
Semiconductor Group
6-31
RMAP=0
RMAP=1
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
1997-10-01
On-Chip Peripheral Components
C509-L
Table 6-4
Special Function Register of the CCU
Symbol
CMSEL
CAFR
CRCH
CRCL
COMSETL
COMSETH
COMCLRL
COMCLRH
SETMSK
CLRMSK
CTCON
CTRELH
CTRELL
CT1RELH
CT1RELL
TH2
TL2
T2CON
CT1CON
PRSC
Description
Address with
Compare Input Select
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
RMAP=0
RMAP=1
F7H
–
CBH
CAH
A1H
A2H
A3H
A4H
A5H
A6H
E1H
DFH
DEH
–
–
CDH
CCH
C8H
BCH
B4H
–
F7H
–
–
–
–
–
–
–
–
–
–
–
DFH
DEH
–
–
–
–
–
The compare/capture registers and reload registers related to compare timer 1 are mapped to the
registers of the compare timer. This means, that they have the same register address. These
compare timer 1 related registers are selected when bit RMAP, which located in the SFR SYSCON,
is set during a register access. If RMAP=0, the compare timer related register are accessed. The
rightmost 2 columns of table 6-4 show the SFR address of each CCU register with the state of bit
RMAP when they are accessed (RMAP description see also chapter 3.5).
Semiconductor Group
6-32
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.1
Timer 2 Operation
Timer 2 is one of the three 16-bit timer units of the capture/compare unit. It can operate as timer,
event counter, or gated timer. Prior to the description of the timer 2 operating modes and functions,
the timer 2 related special function registers are described.
6.3.1.1
Timer 2 Registers
Timer 2 is controlled by bits of the 5 special function register T2CON, PRSC, CTCON, IEN1, and
IRCON0. The related meaning of the timer 2 control bits and flags is shown below.
Special Function Register T2CON (Address C8H)
Special Function Register PRSC (Address B4H)
Special Function Register CTCON (Address E1H)
Special Function Register IEN0
(Address A8H)
Special Function Register IEN1
(Address B8H)
Special Function Register IRCON0 (Address C0H)
Bit No.
MSB
CFH
C8H
T2PS
I3FR
I2FR
T2R1
7
6
5
WDTP
S0P
7
T2PS1
B4H
E1H
AFH
A8H
EAL
BFH
B8H
T2R0
T2CM
T2I1
T1I0
4
3
2
1
0
T2P1
T2P0
T1P1
T1P0
T0P1
T0P0
6
5
4
3
2
1
0
CTP
ICR
ICS
CTF
CLK2
CLK1
CLK0
ADH
ACH
AAH
A9H
A8H
EX1
ET0
WDT
BEH
EXEN2 SWDT
C7H
C0H
C9H
AEH
EXF2
C6H
TF2
ET2
BDH
EX6
C5H
IEX6
CCH
ES0
CBH
LSB
C8H
CAH
CEH
CDH
Reset Value : 00H
Reset Value : 11010101B
Reset Value : 01000000B
Reset Value : 00H
Reset Value : 00H
Reset Value : 00H
ABH
ET1
BCH
EX5
EX4
C4H
IEX5
BBH
C3H
IEX4
EX0
BAH
B9H
B8H
EX3
EX2
EADC
C2H
C1H
C0H
IEX3
IEX2
IADC
T2CON
PRSC
CTCON
IEN0
IEN1
IRCON0
The shaded bits are not used for timer/counter 2.
Semiconductor Group
6-33
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On-Chip Peripheral Components
C509-L
The bits T2PS, T2PS1, T2P1, and T2P0 are prescaler select bits. T2R1 and T2R0 select the reload
mode. T2I1 and T2I0 select the clock input source of timer 2. Bits ET2, EXEN2, EXF2, and TF2 are
interrupt control bits/flags. Detailed bit definition is given in the table below.
Bit
Symbol
T2PS
T2P1
T2P0
T2PS1
Timer 2 prescaler select bits
Based on fOSC/6 these bits define the prescaler divider ratio of the timer 2
input clock according the following table.
T2R1
T2R0
T2I1
T2I0
ET2
Semiconductor Group
T2P1
T2P0
T2PS1
Timer 2
Input Clock
T2PS=0
Timer 2
Input Clock
T2PS=1
0
0
0
fOSC ÷ 6
fOSC ÷ 12
0
0
1
fOSC ÷ 24
fOSC ÷ 48
0
1
0
fOSC ÷ 12
fOSC ÷ 24
0
1
1
fOSC ÷ 48
fOSC ÷ 96
1
0
0
fOSC ÷ 24
fOSC ÷ 48
1
0
1
fOSC ÷ 96
fOSC ÷ 192
1
1
0
fOSC ÷ 48
fOSC ÷ 96
1
1
1
fOSC ÷ 192
fOSC ÷ 384
Timer 2 reload mode selection
T2R1
T2R0
Reload Mode
0
X
Reload disabled
1
0
Mode 0: auto-reload upon timer 2 overflow (TF2)
1
1
Mode 1: reload upon falling edge at pin P1.5 / T2EX
Timer 2 input selection
T2I1
T2I0
Input Mode
0
0
No input selected : timer 2 stops
0
1
Timer function : input frequency see table above
1
0
Counter function : external input controlled by pin
P1.7 / T2
1
1
Gated timer functiol : input controlled by pin T2/P1.7
Timer 2 Interrupt Enable.
If ET2 = 0, the timer 2 interrupt is disabled.
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1997-10-01
On-Chip Peripheral Components
C509-L
Bit
Symbol
EXEN2
Timer 2 external reload interrupt enable
If EXEN2 = 0, the timer 2 external reload interrupt is disabled.
The external reload function is not affected by EXEN2.
EXF2
Timer 2 external reload flag
Set when a reload is caused by a negative transition on pin T2EX while
EXEN2 = 1. If ET2 in IEN0 is set (timer 2 interrupt enabled), EXF2 = 1 will
cause an interrupt. Can be used as an additional external interrupt when
the reload function is not used. EXF2 must be cleared by software.
TF2
Timer 2 overflow flag
Set by a timer 2 overflow and must be cleared by software. If the timer 2
interrupt is enabled, TF2 = 1 will cause an interrupt.
Special Function Registers TL2/TH2
Special Function Registers CRCL/CRCH
(Addresses CCH/CDH)
(Addresses CAH/CBH)
Reset Value : 00H
Reset Value : 00H
Bit No. MSB
7
6
5
4
3
2
1
LSB
0
CCH
.7
.6
.5
.4
.3
.2
.1
.0
TL2
CDH
.7
.6
.5
.4
.3
.2
.1
.0
TH2
CAH
.7
.6
.5
.4
.3
.2
.1
.0
CRCL
CBH
.7
.6
.5
.4
.3
.2
.1
.0
CRCH
Bit
Function
TL2.7 - 0
Timer 2 low byte
TL2 contains the 8-bit low byte of the 16-bit timer 2 count value.
TH2.7 - 0
Timer 2 high byte
TH2 contains the 8-bit high byte of the 16-bit timer 2 count value.
CRCL.7 - 0
Compare/Reload/Capture register low byte
CRCL is the 8-bit low byte of the 16-bit reload register of timer 2. It is also used
for compare/capture functions.
CRCH.7 - 0
Compare/Reload/Capture register high byte
CRCH is the 8-bit high byte of the 16-bit reload register of timer 2. It is also
used for compare/capture functions.
Semiconductor Group
6-35
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.1.2
Timer 2 Operating Modes
Figure 6-18 shows a functional block diagram of the timer 2 unit.
Figure 6-18
Block Diagram of Timer 2
In timer function, the count rate is derived from the oscillator frequency. A prescaler offers the
possibility of selecting a count rate of 1/6 to 1/384 of the oscillator frequency. Thus, the 16-bit timer
register (consisting of TH2 and TL2) is incremented at maximum in every machine cycle. The
prescaler is selected by the bits T2P1, T2P0, T2PS1, and T2PS (definition see previous page).
Semiconductor Group
6-36
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.1.2.1
Gated Timer Mode
In gated timer function, the external input pin P1.7/T2 operates as a gate to the input of timer 2. lf
T2 is high, the internal clock input is gated to the timer. T2 = 0 stops the counting procedure. This
will facilitate pulse width measurements. The external gate signal is sampled once every machine
cycle.
6.3.1.2.2
Event Counter Mode
In the event counter function, the timer 2 is incremented in response to a 1-to-0 transition at its
corresponding external input pin P1.7/T2. In this function, the external input is sampled every
machine cycle. When the sampled inputs show a high in one cycle and a low in the next cycle, the
count is incremented. The new count value appears in the timer register in the cycle following the
one in which the transition was detected. Since it takes two machine cycles (12 oscillator periods)
to recognize a 1-to-0 transition, the maximum count rate is 1/12 of the oscillator frequency. There
are no restrictions on the duty cycle of the external input signal, but to ensure that a given level is
sampled at least once before it changes, it must be held stable for at least one full machine cycle.
Note:
The prescaler must be turned off for proper counter operation of timer 2 (T2P1=T2P0=
T2PS1=T2PS=0).
In either case, no matter whether timer 2 is configured as timer, event counter, or gated timer, a
rolling-over of the count from all 1’s to all 0’s sets the timer overflow flag TF2 (bit 6 in SFR IRCON0,
interrupt request control) which can generate an interrupt.
lf TF2 is used to generate a timer overflow interrupt, the request flag must be cleared by the interrupt
service routine as it could be necessary to check whether it was the TF2 flag or the external reload
request flag EXF2 which requested the interrupt (for EXF2 see below). Both request flags cause the
program to branch to the same vector address.
6.3.1.2.3
Reload of Timer 2
The reload mode for timer 2 (see figure 6-19) is selected by bits T2R0 and T2R1 in SFR T2CON.
Two reload modes are selectable:
In mode 0, when timer 2 rolls over from all 1’s to all 0’s, it not only sets TF2 but also causes the
timer 2 registers to be loaded with the 16-bit value in the CRC register, which is preset by software.
The reload will happen in the same machine cycle in which TF2 is set, thus overwriting the count
value 0000H.
In mode 1, a 16-bit reload from the CRC register is caused by a negative transition at the
corresponding input pin P1.5/T2EX. In addition, this transition will set flag EXF2, if bit EXEN2 in SFR
IEN1 is set.
lf the timer 2 interrupt is enabled, setting EXF2 will generate an interrupt. The external input pin
T2EX is sampled in every machine cycle. When the sampling shows a high in one cycle and a low
in the next cycle, a transition will be recognized. The reload of timer 2 registers will then take place
in the cycle following the one in which the transition was detected.
Semiconductor Group
6-37
1997-10-01
On-Chip Peripheral Components
C509-L
Input
Clock
TL2
TH2
T2EX
P1.5
Mode 1
Reload
Mode 0
CRCL
CRCH
TF2
<1
Timer 2
Interrupt
Request
EXF2
EXEN2
MCS01844
Figure 6-19
Timer 2 in Reload Mode
Semiconductor Group
6-38
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.2
Operation of the Compare Timers
These two timers - the fourth and fifth timer in the C509-L - are implemented to function as a fast
16-bit time base for the compare registers CM0 to CM7 and CC10 to CC17. The compare timers
are combined with the CMx/CC1x registers and can be used for high-speed output purposes or as
a fast 16-bit pulse-width modulation unit.
Prior to the description of the compare timer operating modes and functions, the compare timer
related special function registers are described.
6.3.2.1
Compare Timer and Compare Timer 1 Registers
Each of the two compare timers has a 8-bit control register and a 16-bit reload register. These 6
special function registers are described in this section.
Special Function Register CTCON
Special Function Register CT1CON
Bit No.
E1H
BCH
(Address E1H)
(Address BCH)
Reset Value : 01000000B
Reset Value : X1XX0000B
6
5
4
3
2
1
LSB
0
T2PS1
CTP
ICR
ICS
CTF
CLK2
CLK1
CLK0
7
6
5
4
3
2
1
0
–
CT1P
–
–
MSB
7
CT1F CLK12 CLK11 CLK10
CTCON
CT1CON
The shaded bits are not used for compare timer control.
Bit
Function
ICR
Interrupt request flag for compare register COMCLR
ICR is set when a compare match occurred. ICR is cleared by hardware
when the processor vectors to interrupt routine.
ICS
Interrupt request flag for compare register COMSET
ICS is set when a compare match occurred. ICS is cleared by hardware
when the processor vectors to interrupt routine.
CTF
Compare timer overflow flag
CTF is set when the compare timer 1 count rolls over from all ones to the
reload value. When CTF is set, a compare timer interrupt can be
generated (if enabled). CTF is cleared by hardware when the compare
timer value is no more equal to the reload value.
Semiconductor Group
6-39
1997-10-01
On-Chip Peripheral Components
C509-L
Bit
Function
CTP
CLK2
CLK1
CLK0
Compare timer input clock selection.
Based on fOSC these bits define the prescaler divider ratio of the compare
timer input clock according to the following table
CT1P
CLK12
CLK11
CLK10
CLK2
CLK1
CLK0
Compare Timer
Input Clock
CTP = 0
Compare Timer
Input Clock
CTP = 1
(default after reset)
0
0
0
fOSC
fOSC ÷ 2
0
0
1
fOSC ÷ 2
fOSC ÷ 4
0
1
0
fOSC ÷ 4
fOSC ÷ 8
0
1
1
fOSC ÷ 8
fOSC ÷ 16
1
0
0
fOSC ÷ 16
fOSC ÷ 32
1
0
1
fOSC ÷ 32
fOSC ÷ 64
1
1
0
fOSC ÷ 64
fOSC ÷ 128
1
1
1
fOSC ÷ 128
fOSC ÷ 256
Compare timer 1 input clock selection.
Based on fOSC these bits define the prescaler divider ratio of the compare
timer 1 input clock according to the following table
Compare Timer 1 Compare Timer 1
CLK12 CLK11 CLK10 Input Clock
Input Clock
CT1P = 0
CT1P = 1
CT1F
Semiconductor Group
0
0
0
fOSC
fOSC ÷ 2
0
0
1
fOSC ÷ 2
fOSC ÷ 4
0
1
0
fOSC ÷ 4
fOSC ÷ 8
0
1
1
fOSC ÷ 8
fOSC ÷ 16
1
0
0
fOSC ÷ 16
fOSC ÷ 32
1
0
1
fOSC ÷ 32
fOSC ÷ 64
1
1
0
fOSC ÷ 64
fOSC ÷ 128
1
1
1
fOSC ÷ 128
fOSC ÷ 256
Compare timer 1 overflow flag
CT1F is set when the compare timer 1 count rolls over from all ones to
the reload value. When CT1F is set, a compare timer 1 interrupt can be
generated (if enabled). CT1F is cleared by hardware when the compare
timer 1 value is no more equal its reload value.
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1997-10-01
On-Chip Peripheral Components
C509-L
The reload register of the two compare timers are located at the same SFR addresses.
Special Function Register
Special Function Register
Special Function Register
Special Function Register
Bit No.
MSB
7
CTRELL
CTRELH
CT1RELL
CT1RELH
(Address DEH)
(Address DFH)
(Mapped Address DEH)
(Mapped Address DFH)
Reset Value : 00H
Reset Value : 00H
Reset Value : 00H
Reset Value : 00H
6
5
4
3
2
1
LSB
0
DEH
.7
.6
.5
.4
.3
.2
.1
.0
CTRELL
DFH
.7
.6
.5
.4
.3
.2
.1
.0
CTRELH
DEH
RMAP=1
.7
.6
.5
.4
.3
.2
.1
.0
CT1RELL
DFH
RMAP=1
.7
.6
.5
.4
.3
.2
.1
.0
CT1RELH
Bit
Function
CTRELL.7 - 0
Compare timer reload value low part
The CTRELL register holds the lower 8 bits of the 16-bit reload value for
the compare timer.
CTRELH.7 - 0
Compare timer reload value high part
The CTRELH register holds the upper 8 bits of the 16-bit reload value for
the compare timer.
CT1RELL.7 - 0
Compare timer 1 reload value low part
The CT1RELL register holds the lower 8 bits of the 16-bit reload value
for the compare timer 1.
CT1RELH.7 - 0
Compare timer 1 reload value high part
The CT1RELH register holds the upper 8 bits of the 16-bit reload value
for the compare timer 1.
Semiconductor Group
6-41
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.2.2
Operating Modes of the Compare Timers
The compare timers receive its input clock from a programmable prescaler which provides nine
input frequencies, ranging from fOSC up to fOSC/256. This configuration allows a very high flexibility
concerning timer period length and input clock frequency. The prescaler ratios are selected each
by four bits in the special function registers CTCON and CT1CON. Figure 6-20 shows the block
diagram of the compare timer and compare timer 1.
Figure 6-20
Compare Timer and Compare Timer 1 Block Diagram
Semiconductor Group
6-42
1997-10-01
On-Chip Peripheral Components
C509-L
The compare timers are, once started, free-running 16-bit timers, which on overflow are
automatically reloaded by the contents of the 16-bit reload registers. These reload registers are
CTRELL (compare timer reload register, low byte) and CTRELH (compare timer reload register,
high byte) and the corresponding registers of the compare timer 1 (CTR1RELH, CT1RELH). An
initial writing to the reload register CTRELL/CT1RELL starts the corresponding compare timer. If a
compare timer is already running, a write to CTRELL/CT1RELL again triggers an instantly reload of
the timer, in other words loads the timer in the cycle following the write instruction with the new count
stored in the reload registers CTREL or CT1REL.
When the reload register is to be loaded with a 16-bit value, the high byte of the reload register must
be written first to ensure a determined start or restart position. Writing to the low byte then triggers
the actual reload procedure mentioned above. The 16-bit reload value can be overwritten at any
time.
The compare timer have - as any other timer in the C509-L - their own interrupt request flags CTF
and CT1F. These flags are located in the registers CTCON and CT1CON. CTF/CT1F are set when
the timer count rolls over from all ones to the reload value. They are reset by hardware when the
compare timer value is no more equal to the reload value.
The overflow interrupt eases e.g. software control of pulse width modulated output signals. A
periodic interrupt service routine caused by an overflow of the compare timer can be used to load
new values in the assigned compare registers and thus change the corresponding PWM output
accordingly. More details about interrupt control are discussed in chapter 7.
Semiconductor Group
6-43
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.3
Compare Functions of the CCU
The compare function of a timer/register combination can be described as follows. The 16-bit value
stored in a compare or compare/capture register is compared with the contents of the timer register.
lf the count value in the timer register matches the stored value, an appropriate output signal is
generated at a corresponding port pin.
The contents of a compare register can be regarded as ’time stamp’ at which a dedicated output
reacts in a predefined way (either with a positive or negative transition). Variation of this ’time stamp’
somehow changes the wave of a rectangular output signal at a port pin. This may - as a variation
of the duty cycle of a periodic signal - be used for pulse width modulation as well as for a continually
controlled generation of any kind of square wave forms. In the case of the C509-L, two compare
modes are implemented to cover a wide range of possible applications.
In the C509-L - thanks to the high number of 21 compare registers and two associated timers several timer/compare register combinations are selectable. In some of these configurations one of
the two compare modes may be freely selected, others, however, automatically establish a
compare mode. In the following the two possible modes are generally discussed. This description
will be referred to in later sections where the compare registers are described.
As already mentioned, there are only a few compare registers with their corresponding port circuitry
which are able to serve both compare modes. In most cases the mode is automatically set
depending on the timer which is used as time base or depending on the port which outputs the
compare signal.
Semiconductor Group
6-44
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.3.1 Compare Mode 0
In mode 0, upon matching the timer and compare register contents, the output signal changes from
low to high. lt goes back to a low level on timer overflow. As long as compare mode 0 is enabled,
the appropriate output pin is controlled by the timer circuit only, and not by the user. Writing to the
port will have no effect. Figure 6-21 shows a functional diagram of a port circuit when used in
compare mode 0. The port latch is directly controlled by the timer overflow and compare match
signals. The input line from the internal bus and the write-to-latch line of the port latch are
disconnected when compare mode 0 is enabled.
Compare mode 0 is ideal for generating pulse width modulated output signals, which in turn can be
used for digital-to-analog conversion via a filter network or by the controlled device itself (e.g. the
inductance of a DC or AC motor). Compare mode 0 may also be used for providing output clocks
with initially defined period and duty cycle. This is the mode which needs the least CPU time. Once
set up, the output goes on oscillating without any CPU intervention. Figure 6-22 illustrates the
function of compare mode 0.
Port Circuit
Read Latch
VCC
Compare Register
Circuit
Compare Reg.
16 Bit
Comparator
16 Bit
Compare
Match
S
D
Q
Port
Latch
CLK
Q
R
Internal
Bus
Write to
Latch
Port
Pin
Timer Register
Timer Circuit
Timer
Overflow
Read Pin
MCS02661
Figure 6-21
Port Latch in Compare Mode 0
Figure 6-22 shows a typical output signal waveform which is generated when compare mode 0 is
selected.
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
Timer Count = FFFFH
Timer Count =
Compare Value
Contents
of a Timer
Register
Timer Count = Reload Value
Interrupt can be generated
on overflow
Compare
Output
(P1.x/CCx)
MCT01846
Interrupt can be generated
on compare match
Figure 6-22
Output Waveform of Compare Mode 0
Modulation Range of a PWM Signal and Differences between the Two Timer/Compare
Register Configurations in the CCU
There are two timer/compare register configurations in the CCU which can operate in compare
mode 0 (either timer 2 with a CCx (CRC and CC1 to CC4) register or the compare timer with a CMx
register). They basically operate in the same way, but show some differences concerning their
modulation range when used for PWM.
Generally it can be said that for every PWM generation with n-bit wide compare registers there are
2n different settings for the duty cycle. Starting with a constant low level (0% duty cycle) as the first
setting, the maximum possible duty cycle then would be
(1 – 1/2n) x 100 %
This means that a variation of the duty cycle from 0% to real 100% can never be reached if the
compare register and timer register have the same length. There is always a spike which is as long
as the timer clock period.
In the C509-L there are two different modulation ranges for the above mentioned two timer/compare
register combinations. The difference is the location of the above spike within the timer period: at
the end of a timer period or at the beginning plus the end of a timer period. Please refer to the
description of the CCU relevant timer/register combination in section 6.3.4 for details.
Semiconductor Group
6-46
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.3.2 Compare Mode 1
In compare mode 1, the software adaptively determines the transition of the output signal. This
mode can only be selected for compare registers assigned to timer 2. lt is commonly used when
output signals are not related to a constant signal period (as in a standard PWM generation) but
must be controlled very precisely with high resolution and without jitter. In compare mode 1, both
transitions of a signal can be controlled. Compare outputs in this mode can be regarded as high
speed outputs which are independent of the CPU activity.
lf compare mode 1 is enabled and the software writes to the appropriate output latch at the port, the
new value will not appear at the output pin until the next compare match occurs. Thus, it can be
choosen whether the output signal has to make a new transition (1-to-0 or 0-to-1, depending on the
actual pin-level) or should keep its old value at the time when the timer value matches the stored
compare value.
Figure 6-23 shows a functional diagram of a port circuit configuration in compare mode 1. In this
mode the port circuit consists of two separate latches. One latch (which acts as a "shadow latch")
can be written under software control, but its value will only be transferred to the port latch (and thus
to the port pin) when a compare match occurs.
Port Circuit
Read Latch
VCC
Compare Register
Circuit
Compare Reg.
Internal
Bus
16 Bit
Comparator
16 Bit
Compare
Match
Write to
Latch
D
Shadow
Latch
CLK
Q
D
Q
Port
Latch
CLK
Q
Port
Pin
Timer Register
Timer Circuit
Read Pin
MCS02662
Figure 6-23
Compare Function of Compare Mode 1
Note that the double latch structure is transparent as long as the internal compare signal is active.
While the compare signal is active, a write operation to the port will then change both latches. This
may become important when timer 2 is driven with a slow input clock. In this case the compare
signal could be active for many machine cycles in which the CPU could unintentionally change the
contents of the port latch.
A read-modify-write instruction will read the user-controlled "shadow latch" and write the modified
value back to this “shadow-latch”. A standard read instruction will - as usual - read the pin of the
corresponding compare output.
Semiconductor Group
6-47
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.3.3
Compare Mode 2
In the compare mode 2 in the CCU can be used for the concurrent compare outputs at port 5. In
this compare mode 2 the port 5 pins are no longer general purpose I/O pins or under control of
compare/capture register CC4, but under control of the compare registers COMSET and COMCLR.
These both 16-bit registers are always associated with timer 2 (same as CRC, CC1 to CC4).
In compare mode 2 the concurrent compare output pins at port 5 are used as shown in figure 6-24.:
Port Circuit
Read Latch
COMSET
VCC
16 Bit
Comparator
16 Bit
TH2
Compare
Signal
SETMSK
Bits
Internal
Bus
Write to
Latch
TL2
Timer 2
16 Bit
Comparator
16 Bit
Compare
Signal
S
D
Q
Port
Latch
CLK
Q
R
Port
Pin
CLRMSK
Bits
COMCLR
Read Pin
MCS02663
Figure 6-24
Compare Function of Compare Mode 2
– When a compare match occurs with register COMSET, a high level appears at the pins of port
5 when the corresponding bits in the mask register SETMSK are set.
– When a compare match occurs with register COMCLR, a low level appears at the pins of port
5 when the corresponding bits in the mask register CLRMSK are set.
– Additionally, the port 5 pins which are used for compare mode 2 can also be directly written
using write instructions to SFR P5. Further, the pins can also be read under program control.
If compare mode 2 shall be selected, register CC4 must operate in compare mode 1 (with the
corresponding output pin P1.4); Therefore, compare mode 2 is selected by enabling the compare
function for register CC4 (COCAH4=1; COCAL4=0 SFR CC4EN) and by programming bits
COCOEN0 and COCOEN1 in SFR CC4EN. Like in concurrent compare mode associated with
CC4, the number of port pins at P5 which serve the compare output function can be selected by bits
COCON0-COCON2 (in SFR CC4EN). If a set and reset request occurs at the same time (identical
values in COMSET and COMCLR), the set operation takes precedence. It is also possible to use
only the interrupts which are generated by matches in COMSET and COMCLR without affecting
port 5 (“software compare”). For this “interrupt-only” mode it is not necessary that the compare
function at CC4 is selected.
Semiconductor Group
6-48
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.4
Timer- and Compare-Register Configurations of the CCU
The compare function and the reaction of the corresponding outputs depend on the timer/compare
register combination. Table 6-5 shows the possible configurations of the CCU and the
corresponding compare modes which can be selected. The following sections describe the function
of these configurations.
Table 6-5
CCU Configurations
Assigned
Timer
Compare
Register
Compare Output at
Possible Modes
Timer 2
CRCH/CRCL
CCH1/CCL1
CCH2/CCL2
CCH3/CCL3
CCH4/CCL4
P1.0/INT3/CC0
P1.1/INT4/CC1
P1.2/INT5/CC2
P1.3/INT6/CC3
P1.4/INT2/CC4
Compare mode 0, 1 + Reload
Compare mode 0, 1 / capture
Compare mode 0, 1 / capture
Compare mode 0, 1 / capture
Compare mode 0, 1 / capture
(see 6.3.4.1 and 6.3.4.2)
CCH4/CCL4
P1.4/INT2/CC4
P5.0/CCM0
to
P5.7/CCM7
Compare mode 1
“Concurrent compare“
CMH0/CML0
to
CMH7/CML7
P4.0/CM0
to
P4.7/CM7
Compare mode 0
COMSET
COMCLR
P5.0/CCM0
to
P5.7/CCM7
Compare mode 2
CMH0/CML0
to
CMH7/CML7
P4.0/CM0
to
P4.7/CM7
Compare mode 1
CC1H0/CC1L0
to
CC1H7/CC1L7
P5.0/CCM0
to
P5.7/CCM7
Compare mode 0 / capture
Compare
Timer
Compare
Timer 1
Semiconductor Group
(see 6.3.4.3)
(see 6.3.4.4 and 6.3.4.4.2)
(see 6.3.4.5)
(see 6.3.4.4 and 6.3.4.4.1)
(see 6.3.4.6)
6-49
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.4.1 Timer 2 - Compare Function with Registers CRC, CC1 to CC3
The compare function of registers CRC and CC1 to CC3 is completely compatible with the
corresponding function of the SAB 80C515. Registers CRC, CC1 to CC3 are permanently
connected to timer 2. All four registers are multifunctional as they additionally provide a capture or
a reload capability (CRC register only).
A general selection of the compare/capture function is done in register CCEN. For compare function
they can be used in compare mode 0 or 1, respectively. The compare mode is selected by setting
or clearing bit T2CM in special function register T2CON. Always two bits in register CCEN select
the CRC and CC1 to CC3 register functionality in the following way:
–
–
–
–
Disable compare/capture mode (normal I/O at the pin)
Capture enabled on rising edge at a pin
Compare enabled (pin becomes a compare output)
Capture enabled on a write operation into the low part register of CRC or CC1 to CC3
Special Function Register T2CON (Address C8H)
Special Function Register CCEN (Address C1H)
Bit No.
MSB
CFH
C8H
T2PS
I3FR
I2FR
T2R1
7
6
5
4
C1H
CEH
CDH
CCH
Reset Value : 00H
Reset Value : 00H
CBH
LSB
C8H
CAH
C9H
T2R0
T2CM
T2I1
T1I0
3
2
1
0
COCAH3 COCAL3 COCAH2 COCAL2 COCAH1 COCAL1 COCAH0 COCAL0
T2CON
CCEN
The shaded bits are not used for compare/capture control.
Bit
Function
T2CM
Compare mode control for CCR and CC1 to CC3 registers
When T2CM is cleared, compare mode 0 is selected.
When T2CM is set, compare mode 1 is selected.
COCAH3,
COCAL3
Compare/capture mode for the CC register 3
Semiconductor Group
COCAH3
COCAL3
Mode
0
0
Compare/capture disabled
0
1
Capture on rising edge at pin P1.3/INT6/CC3
1
0
Compare enabled
1
1
Capture on write operation into register CCL3
6-50
1997-10-01
On-Chip Peripheral Components
C509-L
Bit
Function
COCAH2,
COCAL2
Compare/capture mode for the CC register 2
COCAH1,
COCAL1
COCAH0,
COCAL0
COCAH2
COCAL2
Mode
0
0
Compare/capture disabled
0
1
Capture on rising edge at pin P1.2/INT5/CC2
1
0
Compare enabled
1
1
Capture on write operation into register CCL2
Compare/capture mode for the CC register 2
COCAH1
COCAL1
Mode
0
0
Compare/capture disabled
0
1
Capture on rising edge at pin P1.1/INT4/CC1
1
0
Compare enabled
1
1
Capture on write operation into register CCL1
Compare/capture mode for the CC register 2
COCAH0
COCAL0
Mode
0
0
Compare/capture disabled
0
1
Capture on rising edge at pin P1.0/INT3/CC0
1
0
Compare enabled
1
1
Capture on write operation into register CRCL
Figure 6-25 and 6-26 show the general timer/compare register/port latch configuration for registers
CRC and CC1 to CC4 in compare mode 0 and compare mode 1. It also shows the interrupt
capabilities. The compare interrupts of registers CRC and CC4 can be programmed to be either
negative or positive transition activated. Compare interrupts for the CC1 to CC3 registers are
always positive transition activated.
Semiconductor Group
6-51
1997-10-01
On-Chip Peripheral Components
C509-L
IxFR
IEXx
Compare Register
CRC/CCx
Interrupt
Shaded Functions for
CRC and CC4 only
16 Bit
Set Latch
Comparator
16 Bit
TL2
TH2
Compare Signal
Reset Latch
Port Latch
R S R S R S R S R S
Q
Q
Q
Q
Q
Overflow
Timer 2
P1.4/
INT2/
CC4
Interrupt
P1.0/
INT3/
CC0
MCS02664
Figure 6-25
Timer 2 with Registers CRC and CC1 to CC4 in Compare Mode 0
IxFR
IEXx
Shaded Functions for
CRC and CC4 only
Compare Register
CRC/CCx
16 Bit
Comparator
Compare Signal
16 Bit
TH2
TL2
Interrupt
Port
Latch
Circuit
Shadow Latch
Overflow
Interrupt
Timer 2
Output Latch
P1.7
P1.0/
INT3/
CC0
MCS02665
Figure 6-26
Timer 2 with Registers CRC and CC1 to CC4 in Compare Mode 1
Semiconductor Group
6-52
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.4.2
Timer 2 - Capture Function with Registers CRC, CC1 to CC4
Each of the four compare/capture registers CC1 to CC4 and the CRC register can be used to latch
the current 16-bit value of the timer 2 registers TL2 and TH2. Two different modes are provided for
the capture function. In capture mode 0, an external event latches the timer 2 contents to a
dedicated capture register. In capture mode 1, a capture event will occur when the low order byte
of the dedicated 16-bit capture register is written to. This capture mode is provided to allow the
software to read the timer 2 contents “on-the-fly”.
In capture mode 0, the external event causing a capture is
– for CC1 to CC3 registers:
– for the CRC and CC4 register:
A positive transition at pins CC1 to CC3 of port 1
A positive or negative transition at the corresponding pins,
depending on the status of the bits I3FR and I2FR in SFR
T2CON. lf the edge flags are cleared, a capture occurs in
response to a negative transition; if the edge flags are set
a capture occurs in response to a positive transition at pins
P1.0/ INT3/ CC0 and P1.4/ INT2/ CC4.
In both cases the appropriate port 1 pin is used as input and the port latch must be programmed to
contain a one (1). The external input is sampled in every machine cycle. When the sampled input
shows a low (high) level in one cycle and a high (low) in the next cycle, a transition is recognized.
The timer 2 content is latched to the appropriate capture register in the cycle following the one in
which the transition was identified.
In capture mode 0 a transition at the external capture inputs of registers CC0 to CC4 will also set
the corresponding external interrupt request flags IEX2 to IEX6. lf the interrupts are enabled, an
external capture signal will cause the CPU to vector to the appropriate interrupt service routine.
In capture mode 1 a capture occurs in response to a write instruction to the low order byte of a
capture register. The write-to-register signal (e.g. write-to-CRCL) is used to initiate a capture. The
value written to the dedicated capture register is irrelevant for this function. The timer 2 contents will
be latched into the appropriate capture register in the cycle following the write instruction. In this
mode no interrupt request will be generated.
Figures 6-27 and 6-28 show functional diagrams of the capture function of timer 2. Figure 6-27
illustrates the operation of the CRC or CC4 register, while figure 6-28 shows the operation of the
compare/capture registers 1 to 3.
The two capture modes are selected individually for each capture register by bits in SFR CCEN
(compare/capture enable register) and CC4EN (compare/capture 4 enable register). That means,
in contrast to the compare modes, it is possible to simultaneously select capture mode 0 for one
capture register and capture mode 1 for another register.
Semiconductor Group
6-53
1997-10-01
On-Chip Peripheral Components
C509-L
Input
Clock
TL2
TH2
TF2
Timer 2
Interrupt
Request
IEX3
External
Interrupt 3
Request
"Write to
CRCL"
Mode 1
Capture
Mode 0
P1.0/INT 3/
CC0
CRCL
T2 CON.6
CRCH
MCS01855
Figure 6-27
Capture with Registers CRC, CC4
Input
Clock
TL2
TH2
TF2
Timer 2
Interrupt
Request
IEX4
External
Interrupt 4
Request
"Write to
CCL1"
Mode 1
Capture
Mode 0
CCL1
P1.1/INT 4/
CC1
CCH1
MCS01856
Figure 6-28
Capture with Registers CC1 to CC3
Semiconductor Group
6-54
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.4.3
Compare Function of Register CC4; “Concurrent Compare”
Compare register CC4 is permanently assigned to timer 2. lt has its own compare/capture enable
register CC4EN. Register CC4 can be set to operate as any of the other CC registers (see also
figures 6-29 and 6-30). Its output pin is P1.4/CC4/INT2 and it has a dedicated compare mode select
bit COMO located in register CC4EN.
In addition to the standard operation in compare mode 0 or 1, there is another feature called
‘concurrent compare’ which is just an application of compare mode 1 to more than one output pin.
Concurrent compare means that the comparison of CC4 and timer 2 can manipulate up to nine port
pins concurrently. A standard compare register in compare mode 1 normally transfers a
preprogrammed signal level, which is stored in the shadow latch to a single output line. Register
CC4, however, is able to put a 9-bit pattern to nine output lines. The nine output lines consist of one
line at port 1 (P1.4), which is the standard output for register CC4, and additional eight lines at port 5
(see figure 6-29).
Concurrent compare is an ideal and effective option where more than one synchronous output
signal is to be generated. Applications including this requirement could among others be a complex
multiple-phase stepper motor control as well as the control of ignition coils of a car engine. All these
applications have in common that predefined bit-patterns must be put to an output port at a precisely
predefined moment. This moment refers to a special count of timer 2, which was loaded to compare
register CC4.
To Interrupt Logic
Port 5-Shadow Latch
Compare Register CC4
P1.4
S.L.
16 Bit
Comparator
16 Bit
TH2
TL2
Timer 2
COCON1
COCON2
COCON3
COMO
Port 5-Output Buffer
P5.0/
CCM0
P5.7/ P1.4/
CCM7 INT2/
CC4
MCS02666
Figure 6-29
“Concurrent Compare” Function of Register CC4
Semiconductor Group
6-55
1997-10-01
On-Chip Peripheral Components
C509-L
Figure 6-30 gives an example of how to generate eight different rectangular wave forms at port 5
using a pattern table and a time schedule for these patterns. The patterns are moved into port 5
before the corresponding timer count is reached. The (future) timer count at which the pattern shall
appear at the port must be loaded to register CC4. Thus the user can mask each port bit differently
depending on whether he wants the output to be changed or not.
Concurrent compare is enabled by setting bit COCOEN in special function register CC4EN. A ’1’ in
this bit automatically sets compare mode 1 for register CC4, too. A 3-bit field in special function
register CC4EN determines the additional number of output pins at port 5. Port P1.4/CC4/INT2 is
used as a standard output pin in any compare mode for register CC4.
Pattern Table (8 Bit)
Schedule Table (16 Bit)
00 H
55 H
AAH
FF H
1000 H
2000 H
3000 H
4000 H
Compare
CC4H
0
1
Register
CC4L
0
0
Port 5 Latch
00 H
Timer Count
1000 H
2000 H
3000 H
4000 H
P5.7
P5.6
P5.5
P5.4
Port Pattern
P5.3
P5.2
P5.1
P5.0
MCT01853
Figure 6-30
Example for a “Concurrent Compare” Waveform at Port 5
Semiconductor Group
6-56
1997-10-01
On-Chip Peripheral Components
C509-L
Special Function Register CC4EN (Address C9H)
Bit No.
MSB
7
6
5
4
C9H
COCO
EN1
COCO
N2
COCO
N1
COCO
N0
3
Reset Value : 00H
2
1
LSB
0
COCO COCAH4 COCAL4 COMO
EN0
CC4EN
Bit
Function
COCOEN1
COCOEN0
Selection of compare modes 1 and 2 at port 5
For details on mode selection with COCOEN1/COCOEN0 see table 6-6.
COCON2
COCON1
COCON0
Port 5 compare outputs selection
These bits select the number of compare outputs at port 5 according the
following table.
COCON2 COCON1 COCON0 Function
0
0
0
One additional output of CC4 at P5.0
0
0
1
Additional outputs of CC4 at P5.0 to P5.1
0
1
0
Additional outputs of CC4 at P5.0 to P5.2
0
1
1
Additional outputs of CC4 at P5.0 to P5.3
1
0
0
Additional outputs of CC4 at P5.0 to P5.4
1
0
1
Additional outputs of CC4 at P5.0 to P5.5
1
1
0
Additional outputs of CC4 at P5.0 to P5.6
1
1
1
Additional outputs of CC4 at P5.0 to P5.7
COCAH4
COCAL4
Compare/capture mode selection for the CC register 4
For details on mode selection with COCAH4/COCAL4 see table 6-6.
COMO
CC4 compare mode select bit
When set, compare mode 1 is selected for CC4. COMO = 0 selects compare
mode 0 for CC4. Setting of bit COCOEN0 automatically sets COMO.
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
Table 6-6
Configurations for Concurrent Compare Mode and Compare Mode 2 at Port 5
COCAH4 COCAL4 COCOEN1 COCOEN0 Function of CC4
Function of Compare
Modes at P5
0
Disabled
0
0
0
1
0
1
1
1
0
0
1
1
0
0
0
1
0
1
Compare / Capture
disabled
Compare Mode 2
selected at P5
Capture on
falling/rising edge at
pin
P1.4/INT2/CC4
Disabled
Compare enable at
CC4; mode 0/1 is
selected by COMO
Disabled
Compare mode 1 enabled at CC4; COMO
is automatically set
Concurrent compare
(mode 1) selected at
P5
1
1
1
0
1
Compare mode 2
selected, but only
interrupt generation
(ICR, ICS);
no output signals.at P5
Compare mode 2
selected, but only
interrupt generation
(ICR, ICS);
no output signals at P5
Compare mode 2
selected, but only
interrupt generation
(ICR, ICS);
no output signals at P5
Compare mode 2
selected at P5
0
Capture on write
operation into register
CCL4
Disabled
Compare mode 2
selected, but only
interrupt generation
(ICR, ICS);
no output signals at P5
Note : All other combinations of the 4 mode select bits are reserved and must not be used.
Semiconductor Group
6-58
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.4.4 Compare Function of Registers CM0 to CM7
The CCU of the C509-L contains another set of eight compare registers and an additional timer, the
compare timer, and some control SFRs. These compare registers and the compare timer are mainly
dedicated to PWM applications.
The compare registers CM0 to CM7, however, are not permanently assigned to the compare timer,
each register may individually be configured to work either with timer 2 or the compare timer. This
flexible assignment of the CMx registers allows an independent use of two time bases whereby
different application requirements can be met. Any CMx register connected to the compare timer
automatically works in compare mode 0 e.g. to provide fast PWM with low CPU intervention. CMx
registers which are assigned to timer 2, operate in compare mode 1. This allows the CPU to control
the compare output transitions directly.
The assignment of the eight registers CM0 to CM7 to either timer 2 or to the compare timer is done
by a multiplexer which is controlled by the bits in the SFR CMSEL. The compare function itself can
individually be enabled in the SFR CMEN. These two registers are not bit-addressable. This means,
that the value of single bits can only be changed by AND-ing or OR-ing the register with a certain
mask.
Special Function Register CMSEL (Address F7H)
Special Function Register CMEN (Address F6H)
Bit No.
F7H
F6H
Reset Value : 00H
Reset Value : 00H
6
5
4
3
2
1
LSB
0
.7
.6
.5
.4
.3
.2
.1
.0
7
6
5
4
3
2
1
0
.7
.6
.5
.4
.3
.2
.1
.0
MSB
7
CMSEL
CMEN
Bit
Function
CMSEL.7 - 0
Select bits for CMx registers (x = 0-7)
When set, the CMLx/CMHx registers are assigned to the compare timer
and compare mode 0 is enabled. The compare registers are assigned to
timer 2 if CMSELx = 0. In this case compare mode 1 is selected.
CMEN.7 - 0
Enable bits for compare registers CMx (x = 0 - 7)
When set, the compare function is enabled and led to the output lines of
port 4.
Semiconductor Group
6-59
1997-10-01
On-Chip Peripheral Components
C509-L
6.3.4.4.1 CMx Registers Assigned to the Compare Timer
Every CMx register assigned to the compare timer as a time base operates in compare mode 0 and
uses a port 4 pin as an alternate output function.
The "Timer Overflow Controlled" (TOC) Loading
There is one great difference between a CMx register and the other previously described compare
registers: compare outputs controlled by CMx registers have no dedicated interrupt function. They
use a "timer overflow controlled loading" (further on called "TOC loading") to reach the same
performance as an interrupt controlled compare. To show what this "TOC loading" is for, it will be
explained more detailed in the following:
The main advantage of the compare function in general is that the controller’s outputs are precisely
timed by hardware, no matter which task is running on the CPU. This in turn means that the CPU
normally does not know about the timer count. So, if the CPU writes to a compare register only in
relation to the program flow, then it could easily be that a compare register is overwritten before the
timer had the chance to reach the previously loaded compare value. Hence, there must be
something to "synchronize" the loading of the compare registers to the running timer circuitry. This
could either be an interrupt caused by the timer circuitry (as described before) or a special hardware
circuitry.
Thus "TOC-Ioading" means that there is dedicated hardware in the CCU which synchronizes the
loading of the compare registers CMx in such a way that there is no loss of compare events. lt also
relieves the CPU of interrupt load.
A CMx compare register in compare mode 0 consists of two latches. When the CPU tries to access
a CMx register it only addresses a register latch and not the actual compare latch which is
connected to the comparator circuit. The contents of the register latch may be changed by the CPU
at any time because this change would never affect the compare event for the current timer period.
The compare latch (the "actual" latch) holds the compare value for the present timer period. Thus
the CPU only changes the compare event for the next timer period since the loading of the latch is
performed by the timer overflow signal of the compare timer.
This means for an application which uses several PWM outputs that the CPU does not have to
serve every single compare line by an individual interrupt. lt only has to watch the timer overflow of
the compare timer and may then set up the compare events of all compares for the next timer
period. This job may take the whole current timer period since the TOC loading prevents
unintentional overwriting of the actual (and prepared) value in the compare latch.
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
Figure 6-31
Compare Function of a CMx Register Assigned to the Compare Timer
Figure 6-31 shows a more detailed block diagram of a CMx register connected to the compare
timer. lt illustrates that the CPU can only access the special function register CMx; the actual
compare latch is, however, loaded at timer overflow. The timer overflow signal also sets an interrupt
request flag (CTF in register CTCON) which may be used to inform the CPU by an interrupt that a
new timer cycle has started and that the compare values for the next cycle may be programmed
from now on.
The activation of the TOC loading depends on a few conditions described in the following. A TOC
loading is performed only if the CMLx register has been changed by the CPU. A write instruction to
the low byte of the CMx register is used to enable the loading. The 8-bit architecture of the C509-L
requires such a defined enable mechanism because 16-bit values are to be transferred in two
portions (= two instructions).
Imagine the following situation: one instruction (e.g. loading the low byte of the compare register) is
executed just before timer overflow and the other instruction (loading the high byte) after the
overflow. lf there were no "rule", the TOC loading would just load the new low byte into the compare
latch. The high byte - written after timer overflow - would have to wait till the next timer overflow.
The mentioned condition for TOC loading prevents such undesired behavior. lf the user writes the
high byte first then no TOC loading will happen before the low byte has been written - even if there
is a timer overflow in between. lf the user just intends to change the low byte of the compare latch
then the high byte may be left unaffected.
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
Summary of the TOC loading capability :
– The CMx registers are - when assigned to the compare timer - protected from direct loading
by the CPU. A register latch couple provides a defined load time at timer overflow.
– Thus, the CPU has a full timer period to load a new compare value: there is no danger of
overwriting compare values which are still needed in the current timer period.
– When writing a 16-bit compare value, the high byte should be written first since the write-tolow-byte instruction enables a 16-bit wide TOC loading at next timer overflow.
– lf there was no write access to a CMx low byte then no TOC loading will take place.
– Because of the TOC loading, all compare values written to CMx registers are only activated
in the next timer period.
Initializing the Compare Register/Compare Latch Circuit
Normally when the compare function is desired the initialization program would just write to the
compare register (called ’register latch’). The compare latch itself cannot be accessed directly by a
move instruction, it is exclusively loaded by the timer overflow signal.
In some very special cases, however, an initial loading of the compare latch could be desirable. lf
the following sequence is observed during initialization then latches, the register and the compare
latch, can be loaded before the compare mode is enabled.
Action:
Comment:
Select compare mode 1 (CMSEL.x = 0).
This is also the default value after reset.
Move the compare value for the first timer
period to the compare register CMx (high
byte first).
In compare mode 1 latch is loaded directly
after a write-to-CMLx. Thus the value slips
directly into the compare latch.
Switch on compare mode 0 (CMSEL.x = 1).
Now select the right compare mode.
Move the compare value for the second
timer period to the compare register.
The register latch is loaded. This value is
used after the first timer overflow.
Enable the compare function
(CMEN.x = 1)
Set up the prescaler for the compare timer.
Set specific compare output to low level
(CLR P4.x)
The compare output is switched to low level.
Start the compare timer with a desired value
(write-to-CTREL)
Compare function is initialized.
The output will oscillate.
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6.3.4.4.2
CMx Registers Assigned to the Timer 2
Any CMx register assigned to timer 2 as a time base operates in compare mode 1. In this case CMx
registers behave like any other compare register connected to timer 2 (e.g. the CRC or CCx
registers).
Since there are no dedicated interrupts for the CMx compare outputs, again a buffered compare
register structure is used to determine an exact 16-bit wide loading of the compare value: the
compare value is transferred to the actual compare latches at a write-to-CMLx instruction (low byte
of CMx). Thus, the CMx register is to be written in a fixed order, too: high byte first, low byte second.
lf the high byte may remain unchanged it is sufficient to load only the low byte. See figure 6-32,
block diagram of a CMx register connected to timer 2.
Figure 6-32
CMx-Register Assigned to Timer 2
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6.3.4.5
Timer 2 Operating in Compare Mode 2
The compare mode 2 of the CCU can be used for the concurrent compare output function at port 5.
In compare mode 2, the port 5 pins are no longer general purpose I/O pins or under control of the
compare/capture register CC4, but under control of the compare registers COMSET and COMCLR.
The details of compare mode 2 are already described in section 6.3.3.3. Figure 6-33 shows the
complete compare mode 2 configuration of the CCU and the port 5 pins.
Timer II
Comparator
Comparator
COMSET
COMCLR
ICS
Bit 0
S Q
R
P5.0
Bit 1
S Q
R
P5.1
S Q
R
P5.7
Bit 2
ICR
ECS
(IEN2.4)
SETMSK
ECS
(IEN2.5)
Bit 7
Number
of Pins
for this
function is
selectable
from
1 to 8
by Bit
COCOEN0-2
(in CC4EN).
CLRMSK
Int.
Request
Vector
00A3 H
Int.
Request
Vector
00AB H
Bit 0
Bit 1
Bit 2
Bit 7
MCB02249
Figure 6-33
Compare Mode 2 (Port 5 only)
The compare registers COMSET and COMCLR have their dedicated interrupt vectors. The
corresponding request flags are ICS for register COMSET and ICR for register COMCLR. The flags
are set by a match in registers COMSET and COMCLR, when enabled. As long as the match
condition is valid the request flags can't be reset (neither by hardware nor software). The request
flags are located in SFR CTCON.
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6.3.4.6
Compare / Capture Operation with Compare Timer 1
The C509-L Compare/Capture Unit (CCU) has a third timer - the compare timer 1 (CT1). This timer
is assigned to port 9. The port 9 alternate functions are dedicated for the CT1 controlled
compare/capture capability.
The compare/capture registers, the reload registers, and the control registers (except CT1CON)
related to compare timer 1 are mapped to the registers of the compare timer. This means, that the
CT1 registers have the same register address as the compare timer registers. The compare timer
1 related registers are selected when bit RMAP, which located in the SFR SYSCON, is set during
a register access. If RMAP=0, the compare timer related register are accessed.
As an extract from table 6-4, table 6-4 lists all CT1 registers which are mapped to the compare
timer registers. Further details about the RMAP bit are given in chapter 3.5.
Table 6-7
Compare Timer / Compare Timer 1 Related Mapped Special Function Registers of the CCU
Address
Symbol
Description
Access by
RMAP =
D2H
CML0
CC1L0
Compare Register 0, Low Byte
Compare/Capture 1 Register 0, Low Byte
0
1
D3H
CMH0
CC1H0
Compare Register 0, High Byte
Compare/Capture 1 Register 0, High Byte
0
1
D4H
CML1
CC1L1
Compare Register 1, Low Byte
Compare/Capture 1 Register 1, Low Byte
0
1
D5H
CMH1
CC1H1
Compare Register 1, High Byte
Compare/Capture 1 Register 1, High Byte
0
1
D6H
CML2
CC1L2
Compare Register 2, Low Byte
Compare/Capture 1 Register 2, Low Byte
0
1
D7H
CMH2
CC1H2
Compare Register 2, High Byte
Compare/Capture 1 Register 2, High Byte
0
1
E2H
CML3
CC1L3
Compare Register 3, Low Byte
Compare/Capture 1 Register 3, Low Byte
0
1
E3H
CMH3
CC1H3
Compare Register 3, High Byte
Compare/Capture 1 Register 3, High Byte
0
1
E4H
CML4
CC1L4
Compare Register 4, Low Byte
Compare/Capture 1 Register 4, Low Byte
0
1
E5H
CMH4
CC1H4
Compare Register 4, High Byte
Compare/Capture 1 Register 4, High Byte
0
1
E6H
CML5
CC1L5
Compare Register 5, Low Byte
Compare/Capture 1 Register 5, Low Byte
0
1
E7H
CMH5
CC1H5
Compare Register 5, High Byte
Compare/Capture 1 Register 5, High Byte
0
1
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Table 6-7
Compare Timer / Compare Timer 1 Related Mapped Special Function Registers of the CCU
(cont’d)
Address
Symbol
Description
Access by
RMAP =
F2H
CML6
CC1L6
Compare Register 6, Low Byte
Compare/Capture 1 Register 6, Low Byte
0
1
F3H
CMH6
CC1H6
Compare Register 6, High Byte
Compare/Capture 1 Register 6, High Byte
0
1
F4H
CML7
CC1L7
Compare Register 7, Low Byte
Compare/Capture 1 Register 7, Low Byte
0
1
F5H
CMH7
CC1H7
Compare Register 7, High Byte
Compare/Capture 1 Register 7, High Byte
0
1
F6H
CMEN
CC1EN
Compare Enable Register
Compare/Capture Enable Register
0
1
F7H
CMSEL
CAFR
Compare Input Select
Capture 1, Falling/Rising Edge Register
0
1
DEH
CTRELL
CT1RELL
Compare Timer Reload Register, Low Byte
Compare Timer 1 Reload Register, Low Byte
0
1
DFH
CTRELH
CT1RELH
Compare Timer Reload Register, High Byte
Compare Timer 1 Reload Register, High Byte
0
1
The SFR CT1CON contains the control bits for the input clock selection and the compare timer 1
overflow flag CT1F. CT1CON and the reload registers (CT1RELL, CT1RELH) are described in
detail in section 6.3.2.
The SFR CC1EN contains the enable bits for the compare/capture registers CC10 to CC17. When
set, compare/capture function is enabled and connected to the port 9 pins. AFR CC1EN is a
mapped register.and can only be accessed when bit RMAP in SFR SYSCON is set.
Special Function Register CC1EN (Mapped Address F6H)
Bit No.
F6H
Reset Value : 00H
MSB
7
6
5
4
3
2
1
LSB
0
.7
.6
.5
.4
.3
.2
.1
.0
CC1EN
Bit
Function
CC1EN.7 - 0
Compare timer 1 capture/compare register enable bits
If CC1EN.x is set, the compare/capture function for P9.x is enabled and the port
line is connected with the corresponding compare/capture register CC(10+x).
If CC1EN.x is cleared, the port pin P9.x operates as standard digital I/O.
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6.3.4.6.1 Compare Function of Registers CC10 to CC17
The compare function of the registers CC10 to CC17 is equivalent to the compare function of the
CM1 to CM7 registers (when CM0-7 are controlled by the compare timer). The compare timer 1
configuration operates in compare mode 0. The description of the compare mode operation of the
CMx registers which is given in detail in section 6.3.4.4.1, is also valid for the compare mode
operation of the CC1x registers. Only the compare output port, the enable control, and the compare
timer flag are different.
Figure 6-34 below shows the CC1x registers when they are used for compare function.
Figure 6-34
Compare Function of a CC1x Register Assigned to the Compare Timer 1
The compare function of the compare time 1 configuration is selected by programming the direction
register of port 9 (DIR9) with the direction bit = 0. The direction register DIR9 is written to by a double
instruction sequence (first instruction sets PDIR in SFR IP1, second instruction writes to direction
register). The direction register has the same address as port 9.
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6.3.4.6.2 Capture Function of Registers CC10 to CC17
The capture function is selected by programming the direction register related to port 9 (DIR9). With
the direction bit of DIR9 = 1 the capture function at the corresponding port 9 pin is selected. Each
of the eight compare/capture registers CC10 to CC17 can be used to latch the current 16-bit value
of the compare timer 1 registers by a positive or a negative transition at the corresponding port 9 pin.
The bits located in the SFR CAFR are used to define selectively, whether a positive or a negative
transition at a port 9 pin forces a capture event. CAFR is a mapped register.and can only be
accessed when bit RMAP in SFR SYSCON is set.
Special Function Register CAFR (Mapped Address F7H)
Bit No.
F7H
Reset Value : 00H
MSB
7
6
5
4
3
2
1
LSB
0
.7
.6
.5
.4
.3
.2
.1
.0
CAFR
Bit
Function
CAFR.7-0
Capture on falling / rising edge selection bits
CAFR.x = 0 : Capture into CC(10+x) on falling edge at pin P9.x is selected
(reset value)
CAFR.x = 1 : Capture into CC(10+x) on rising edge at pin P9.x is selected.)
The level at the corresponding port 9 pin is sampled every state within a machine cycle. For
example, with fosc = 16 MHz a state lasts for 62.5 ns. When the compare timer 1 input clock is
selected to fosc, the resulting resolution is 125 ns. The rise/fall time of the external capture signal
must be observed.
At a capture event with the CC10-CC17 register the corresponding interrupt request flag which is
located in SFR IRCON2 is set
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6.3.5
Modulation Range in Compare Mode 0
In compare mode 0, a 100% variation of the duty cycle of a PWM signal cannot be reached. A time
portion of 1/(2n) of an n-bit timer period is always left over. This "spike" may either appear when the
compare register is set to the reload value (limiting the lower end of the modulation range) or it may
occur at the end of a timer period.
In a timer 2 / CCx register configuration in compare mode 0 this spike is divided into two halves:
one at the beginning when the contents of the compare register is equal to the reload value of the
timer; the other half when the compare register is equal to the maximum value of the timer register
(here: FFFFH). Please refer to figure 6-35 where the maximum and minimum duty cycle of a
compare output signal is illustrated. Timer 2 is incremented with the processor cycle (fOSC/6), thus
at 12-MHz operating frequency, these spikes are both approx. 250 ns long.
CCHx/CCLx = 0000 H or = CRCH/CRCL (maximum duty cycle)
H
P1.x
L
Appr. 1/2 of a Machine Cycle
CCHx/CCLx = FFFF H (minimum duty cycle)
Appr. 1/2 of a Machine Cycle
H
P1.x
L
MCT01851
Figure 6-35
Modulation Range of a PMW Signal Generated with a Timer 2 / CCx Register Combination in
Compare Mode 0
The following example shows how to calculate the modulation range for a PWM signal. For the
calculation with reasonable numbers, a reduction of the resolution to 8-bit is used. Otherwise (for
the maximum resolution of 16-bit) the modulation range would be so severely limited that it would
be negligible.
Example:
Timer 2 in auto-reload mode; contents of reload register CRC = FF00H
Restriction of modulation. range =
1
256 x 2
x 100% = 0.195%
This leads to a variation of the duty cycle from 0.195% to 99.805% for a timer 2 / CCx register
configuration when 8 of 16 bits are used.
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In a compare timer/CMx register configuration, the compare output is set to a constant high level if
the contents of the compare registers are equal to the reload register (CTREL). The compare output
shows a high level for one timer clock period when a CMx register is set to FFFFH. Thus, the duty
cycle can be varied from 0.xx% to 100% depending on the resolution selected. In figure 6-36 the
maximum and minimum duty cycle of a compare output signal is illustrated. One clock period of the
compare timer is equal to one machine state (= 1 oscillator periods) if the prescaler is off. Thus, at
12 MHz system clock the spike is approx. 83.3 ns long.
a) CMHx/CMLx = CTREL (maximum duty cycle)
H
P4.x
L
b) CMHx/CMLx = FFFF H (minimum duty cycle)
CTREL =/ FFFF H
One machine state or two oscillator cycle
H
P4.x
L
MCT01854
Figure 6-36
Modulation Range of a PWM Signal Generated with a Compare Timer/CMx Register
Combination
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6.3.6
Using Interrupts in Combination with the Compare Function
The compare service of registers CRC, CC1, CC2, CC3 and CC4 is assigned to alternate output
functions at port pins P1.0 to P1.4. Another option of these pins is that they can be used as external
interrupt inputs. However, when using the port lines as compare outputs then the input line from the
port pin to the interrupt system is disconnected (but the pin’s level can still be read under software
control). Thus, a change of the pin’s level will not cause a setting of the corresponding interrupt flag.
In this case, the interrupt input is directly connected to the (internal) compare signal thus providing
a compare interrupt.
The compare interrupt can be used very effectively to change the contents of the compare registers
or to determine the level of the port outputs for the next "compare match". The principle is, that the
internal compare signal (generated at a match between timer count and register contents) not only
manipulates the compare output but also sets the corresponding interrupt request flag. Thus, the
current task of the CPU is interrupted - of course provided the priority of the compare interrupt is
higher than the present task priority - and the corresponding interrupt service routine is called. This
service routine then sets up all the necessary parameters for the next compare event.
6.3.6.1
Some advantages in using compare interrupts
Firstly, there is no danger of unintentional overwriting a compare register before a match has been
reached. This could happen when the CPU writes to the compare register without knowing about
the actual timer 2 count.
Secondly, and this is the most interesting advantage of the compare feature, the output pin is
exclusively controlled by hardware therefore completely independent from any service delay which
in real time applications could be disastrous. The compare interrupt in turn is not sensitive to such
delays since it loads the parameters for the next event. This in turn is supposed to happen after a
sufficient space of time.
Please note two special cases where a program using compare interrupts could show a "surprising"
behavior:
The first configuration has already been mentioned in the description of compare mode 1. The fact
that the compare interrupts are transition activated becomes important when driving timer 2 with a
slow external clock. In this case it should be carefully considered that the compare signal is active
as long as the timer 2 count is equal to the contents of the corresponding compare register, and that
the compare signal has a rising and a falling edge. Furthermore, the "shadow latches" used in
compare mode 1 are transparent while the compare signal is active.
Thus, with a slow input clock for timer 2, the comparator signal is active for a long time (= high
number of machine cycles) and therefore a fast interrupt controlled reload of the compare register
could not only change the "shadow latch" - as probably intended - but also the output buffer.
When using the CRC or CC4 register, you can select whether an interrupt should be generated
when the compare signal goes active or inactive, depending on the status of bits I3FR or I2FR in
T2CON, respectively.
Initializing the interrupt to be negative transition triggered is advisive in the above case. Then the
compare signal is already inactive and any write access to the port latch just changes the contents
of the "shadow-latch".
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Please note that for CC registers 1 to 3 an interrupt is always requested when the compare signal
goes active.
The second configuration which should be noted is when compare functions are combined with
negative transition activated interrupts. lf the port latch of port P1.0 or P.1.4 contains a 1, the
interrupt request flags IEX3 or IEX2 will immediately be set after enabling the compare mode for the
CRC or CC4 register. The reason is that first the external interrupt input is controlled by the pin’s
level. When the compare option is enabled the interrupt logic input is switched to the internal
compare signal, which carries a low level when no true comparison is detected. So the interrupt
logic sees a 1-to-0 edge and sets the interrupt request flag.
An unintentional generation of an interrupt during compare initialization can be prevented if the
request flag is cleared by software after the compare is activated and before the external interrupt
is enabled.
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6.3.6.2
Interrupt Enable Bits of the Compare/Capture Unit
This section summarizes all CCU related interrupt enable control bits. The interrupt enable bits for
the two compare timers and the compare match and capture interrupt capture are located in the
three SFRs IEN2, IEN3, and EICC1. Note : EICC1 is a mapped SFR (by bit PDIR):
Special Function Register IEN2 (Address 9AH)
Special Function Register IEN3 (Address BEH)
Special Function Register EICC1 (Mapped Address BFH)
Bit No.
9AH
BEH
BFH
Reset Value : XX0000X0B
Reset Value : XXXX00XXB
Reset Value : FFH
MSB
7
6
5
4
3
2
1
LSB
0
–
–
ECR
ECS
ECT
ECMP
–
ES1
7
6
5
4
3
2
1
0
–
–
–
–
ECT1
ECC1
–
–
7
6
5
4
3
2
1
0
EICC17 EICC16 EICC15 EICC14 EICC13 EICC12 EICC11 EICC10
IEN2
IEN3
EICC1
The shaded bits are not used for CCU interrupt control.
Bit
Function
ECR
COMCLR register compare match interrupt enable
If ECR = 0, the COMCLR compare match interrupt is disabled.
ECS
COMSET register compare match interrupt enable
If ECS = 0, the COMSET compare match interrupt is disabled.
ECT
Enable compare timer interrupt
If ECT = 0, the compare timer overflow interrupt is disabled.
ECMP
CM0-7 register compare match interrupt
If ECMP = 0, the CM0-7 compare match interrupt is disabled.
ECT1
Compare timer 1 overflow interrupt enable
If ECT1 = 0, the interrupt at compare timer 1 overflow is disabled.
ECC1
Compare timer 1, general capture/compare interrupt enable
This bit enables the interrupt on an capture/compare event in the capture/compare
registers CC10 - CC17. Additionally, the SFR EICC1 must be programmed to
enable the interrupt request. With ECC1=0, the general capture/compare timer 1
interrupt is disabled.
EICC17 EICC10
Compare timer 1, specific capture/compare interrupt enable
This bit enables the interrupt on an capture/compare event in the capture/compare
registers CC10 - CC17. When EICC1x=0, the interrupt request flag ICC1x has no
effect on the interrupt unit. EICC17 refers to CC17 etc.
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6.3.6.3
Interrupt Flags of the Compare/Capture Unit
This section summarizes the CCU related compare match interrupt flags. The two compare timer
overflow interrupt flags (CT and CT1) are described in detail in section 6.3.2.1.
The compare timer match interrupt occurs on a compare match of the CM0 to CM7 registers with
the compare timer when compare mode 1 is selected for the corresponding channel. There are 8
compare match interrupt flags available in SFR IRCON1 which are or-ed together for a single
interrupt request. Thus, a compare match interrupt service routine has to check which compare
match has requested the compare match interrupt. The ICMPx flags must be cleared by software.
Only if timer 2 is assigned to the CMx registers (compare mode 0), an ICMPx request flag is set by
every match in the compare channel. When the compare timer is assigned to the CMx registers
(compare mode 1), an ICMPx request flag will not be set by a compare match event.
The compare timer 1 match interrupt occurs on a compare match of the CC10 to CC17 registers
with the compare timer 1. There are 8 compare match interrupt flags available in SFR IRCON2
which are or-ed together for a single interrupt request. Thus, a compare match interrupt service
routine has to check which compare match has requested the compare match interrupt. The ICC1x
flags must be cleared by software.
Special Function Register IRCON1 (Address D1H)
Special Function Register IRCON2 (Address BFH)
Bit No.
D1H
MSB
7
5
4
3
2
1
LSB
0
ICMP7 ICMP6 ICMP5 ICMP4 ICMP3 ICMP2 ICMP1 ICMP0
7
BFH
6
Reset Value : 00H
Reset Value : 00H
6
5
4
3
2
1
IRCON1
0
ICC17 ICC16 ICC15 ICC14 ICC13 ICC12 ICC11 ICC10
IRCON2
Bit
Function
ICMP7 - 0
Compare timer match with register CM7 - CM0 interrupt flags
ICMPx is set by hardware when a compare match of the compare timer with the
compare register CMx occurs but only if the compare function for CMx has been
enabled. ICMPx must be cleared by software (CMSEL.x = 0 and CMEN.x = 1).
ICC17 - 10
Compare timer 1 match with register CC17 - CC10 interrupt flags
ICC1x is set by hardware when a compare match of the compare timer 1 with the
compare register CC1x occurs but only if the compare function for CC1x has been
enabled. ICC1x must be cleared by software.
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6.4
Arithmetic Unit
This on-chip arithmetic unit of the C509-L provides fast 32-bit division, 16-bit multiplication as well
as shift and normalize features. All operations are unsigned integer operations.
The arithmetic unit (further on also called MDU for “Multiplication/Division Unit”) has been integrated
to support the C500 core of the C509-L in real-time control applications. It can increase the
execution speed of math-intensive software routines by factor 5 to 10.
The MDU is handled by seven registers, which are memory mapped as special function registers
like any other registers for peripheral control. Therefore, the arithmetic unit allows operations
concurrently to and independent of the CPU’s activity. Table 6-8 describes the four general
operations the MDU is able to perform:
Table 6-8
MDU Operation Characteristics
Operation
Result
Remainder
Execution Time
32bit/16bit
16bit/16bit
16bit x 16bit
32-bit normalize
32-bit shift L/R
32bit
16bit
32bit
–
–
16bit
16bit
–
–
–
6 tCY 1)
4 tCY 1)
4 tCY 1)
6 tCY 2)
6 tCY 2)
1)
2)
1 tCY = 6 • CLP = 1 machine cycle = 375 ns at 16-MHz oscillator frequency
The maximal shift speed is 6 shifts per machine cycle
6.4.1
MDU Register
The seven SFRs of the MDU consist of registers MD0 to MD5, which contain the operands and the
result (or the remainder, resp.) and one control register called ARCON.
Thus MD0 to MD5 are used twofold:
– for the operands before a calculation has been started and
– for storage of the result or remainder after a calculation.
This means that any calculation of the MDU overwrites its operands. lf a program needs the original
operands for further use, they should be stored in general purpose registers in the internal RAM.
Table 6-8 list the MDU registers with its addresses:
Table 6-9
MDU Registers
SFR
Address
Name
ARCON
MD0
MD1
MD2
MD3
MD4
MD5
EFH
E9H
EAH
EBH
ECH
EDH
EEH
MDU Control Register
MDU Data Register 0
MDU Data Register 1
MDU Data Register 2
MDU Data Register 3
MDU Data Register 4
MDU Data Register 5
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The arithmetic control register ARCON contains control flags and the shift counter of the MDU. It
triggers a shift or a normalize operation in register MD0 to MD3 when being written to.
Special Function Register ARCON (Address EFH)
Bit No.
EFH
MSB
7
6
MDEF MDOV
Reset Value : 0XXXXXXXB
5
4
3
2
1
LSB
0
SLR
SC.4
SC.3
SC.2
SC.1
SC.0
ARCON
Bit
Function
MDEF
Error flag
Indicates an improperly performed operation. MDEF is set by hardware
when an operation is retriggered by a write access to MDx before the first
operation has been completed. MDEF is automatically cleared after being
read.
MDOV
Overflow flag
Exclusively controlled by hardware. MDOV is set by following events:
– division by zero
– multiplication with a result greater than FFFFH.
SLR
Shift direction bit
When set, shift right is performed. SLR = 0 selects shift left operation.
SC.4 - SC.0
Shift counter bits
When preset with 00000B, normalizing is selected. After operation SC.0 to
SC.4 contain the number of normalizing shifts performed. When set with a
value ≠ 0, shift operation is started. The number of shifts performed is
determined by the count written to SC.0 to SC.4.
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6.4.2
Operation of the MDU
The MDU can be regarded as a special coprocessor for multiplication, division and shift. Its
operations can be divided into three phases (see figure 6-37):
1) Loading the MDx registers
2) Executing the calculation
3) Reading the result from the MDx registers
During phase two, the MDU works on its own parallelly to the CPU. Execution times of the above
table refer to this phase. Because of the fast operation and the determined execution time for C509L’s instructions, there is no need for a busy flag. The CPU may execute a determined number of
instructions before the result is fetched. The result and the remainder of an operation may also be
stored in the MDx registers for later use.
Phase one and phase three require CPU activity. In these phases the CPU has to transfer the
operands and fetch the results.
Figure 6-37
Operating Phases of the MDU
The MDU has no dedicated instruction register (only for shift and normalize operations, register
ARCON is used in such a way). The type of calculation the MDU has to perform is selected following
the order in which the MDx registers are written to (see table 6-10). This mechanism also reduces
execution time spent for controlling the MDU. Hence, a special write sequence selects an operation.
The MDU monitors the whole write and read-out sequence to ensure that the CPU has fetched the
result correctly and was not interrupted by another calculation task.
Thus, a complete operation lasts from writing the first byte of the operand in phase 1 until reading
the last byte of the result in phase 3.
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6.4.3
Multiplication/Division
The general mechanism to start an MDU activity has been described above. The following
description of the write and read sequences adds to the information given in the table below where
the write and read operations necessary for a multiplication or division are listed.
Table 6-10
Programming the MDU for Multiplication and Division
Operation
32Bit/16Bit
16Bit/16Bit
16Bit x 16Bit
First Write
MD0
MD1
MD2
MD3
MD4
MD5
D’endL
D’end
D’end
D’endH
D’orL
D’orH
MD0
MD1
D’endL
D’endH
MD0
MD4
M’andL
M’orL
MD4
D’orL
MD1
M’andH
MD5
D’orH
MD5
M’orH
MD0
MD1
MD2
MD3
MD4
MD5
QuoL
Quo
Quo
QuoH
RemL
RemH
MD0
MD1
QuoL
QuoH
MD0
MD1
PrL
MD4
RemL
MD2
MD5
RemH
MD3
Last Write
First Read
Last Read
PrH
Abbreviations :
D'end
: Dividend, 1st operand of division
D'or
: Divisor, 2nd operand of division
M'and
: Multiplicand, 1st operand of multiplication
M'or
: Multiplicator, 2nd operand of multiplication
Pr
: Product, result of multiplication
Rem
: Remainder
Quo
: Quotient, result of division
...L
: means, that this byte is the least significant of the 16-bit or 32-bit operand
...H
: means, that this byte is the most significant of the 16-bit or 32-bit operand
Write Sequence
The first and the last write operation in phase one are fixed for every calculation of the MDU. All
write operations inbetween determine the type of MDU calculation.
– A write-to-MD0 is the first transfer to be done in any case. This write resets the MDU and
triggers the error flag mechanism (see below).
– The next two or three write operations select the calculation type (32bit/16bit, 16bit/16bit,
16bit x 16bit)
The last write-to-MD5 finally starts the selected MUL/DIV operation
Read Sequence
– Any read-out of the MDx registers should begin with MD0
– The last read from MD5 (division) or MD3 (multiplication) determines the end of a whole
calculation and releases the error flag mechanism.
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There is no restriction on the time within which a calculation must be completed. The CPU is allowed
to continue the program simultaneously to phase 2 and to fetch the result bytes at any time.
lf the user’s program takes care that interrupting a calculation is not possible, monitoring of the
calculation process is probably not needed. In this case, only the write sequence must be observed.
Any new write access to MD0 starts a new calculation, no matter whether the read-out of the former
result has been completed or not.
6.4.4
Normalize and Shift
Register ARCON controls an up to 32-bit wide normalize and shift operation in registers MD0 to
MD3. It also contains the overflow flag and the error flag which are described in the next two
sections.
Write Sequence
– A write-to-MD0 is also the first transfer to be done for normalize and shift. This write resets
the MDU and triggers the error flag mechanism (see below).
– To start a shift or normalize operation the last write must access register ARCON.
Read Sequence
– The order in which the first three registers MD0 to MD2 are read is not critical
– The last read from MD3 determines the end of a whole shift or normalize procedure and
releases the error flag mechanism.
Note: Any write access to ARCON triggers a shift or normalize operation and therefore changes the
contents of registers MD0 to MD3!
Normalizing
Normalizing is done on an integer variable stored in MD0 (least significant byte) to MD3 (most
significant byte). This feature is mainly meant to support applications where floating point arithmetic
is used. “To normalize” means, that all reading zeroes of an integer variable in registers MD0 to
MD3 are removed by shift left operations. The whole operation is completed when the MSB (most
significant bit) contains a ‘1’.
To select a normalize operation, the five bit field ARCON.0 to ARCON.4 must be cleared. That
means, a write-to-ARCON instruction with the value XXX0 0000B starts the operation.
After normalizing, bits ARCON.0 to ARCON.4 contain the number of shift left operations which were
done. This number may further on be used as an exponent. The maximum number of shifts in a
normalize operation is 31 (= 25 – 1). The operation takes six machine cycles at most, that means 3
microseconds at 12 MHz.
Shifting
In the same way - by a write-to-ARCON instruction - a shift left/right operation can be started. In this
case register bit SLR (ARCON.5) has to contain the shift direction, and ARCON.0 to ARCON.4 the
shift count (which must not be 0, otherwise a normalize operation would be executed). During shift,
zeroes come into the left or right end of the registers MD0 or MD3, respectively.
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The first machine cycle of a shift left/right operation executes four shifts, while all following cycles
perform 6 shifts. Hence, a 31-bit shift takes 3 microseconds at 12 MHz. WIth a four bit shift operation
ther must be at least one machine cycle delay before the result registers MD0-3 can be accessed
as valid by the CPU.
Completion of both operations, normalize and shift, can also be controlled by the error flag
mechanism. The error flag is set if one of the relevant registers (MD0 through MD3) is accessed
before the previously commenced operation has been completed.
For proper operation of the error flag mechanism, it is necessary to take care that the right write or
read sequence to or from registers MD0 to MD3 (see table 6-11) is maintained.
Table 6-11
Programming a Shift or Normalize Operation
Operation
Normalize, Shift Left, Shift Right
First write
MD0
MD1
MD2
MD3
ARCON
least significant byte
.
.
most significant byte
start of conversion
MD0
MD1
MD2
MD3
least significant byte
.
.
most significant byte
Last write
First read
Last read
6.4.5
The Overflow Flag
An overflow flag is provided for some exceptions during MDU calculations. There are three cases
where flag MDOV ARCON.6 is set by hardware:
– Division by zero
– Multiplication with a result greater then 0000 FFFFH
(= auxiliary carry of the lower 16bit)
– Start of normalizing if the most significant bit of MD3 is set (MD3.7 = 1).
Any operation of the MDU which does not match the above conditions clears the overflow flag. Note
that the overflow flag is exclusively controlled by hardware. It cannot be written to.
6.4.6
The Error Flag
An error flag, bit MDEF in register ARCON (figure 6-56), is provided to indicate whether one of the
arithmetic operations of the MDU (multiplication, division, normalize, shift left/right) has been
restarted or interrupted by a new operation.
This can possibly happen e.g. when an interrupt service routine interrupts the writing or reading
sequence of the arithmetic operation in the main program and starts a new operation. Then the
contents of the corresponding registers are indeterminate (they would normally show the result of
the last operation executed).
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In this case the error flag can be used to indicate whether the values in the registers MD0 to MD5
are the expected ones or whether the operation must be repeated. For a multiplication/division, the
error flag mechanism is automatically enabled with the first write instruction to MD0 (phase 1).
According to the above described programming sequences, this is the first action for every type of
calculation. The mechanism is disabled with the final read instruction from MD3 or MD5 (phase 3).
Every instruction which rewrites MD0 (and therefore tries to start a new calculation) in phases 1
through 3 of the same process sets the error flag.
The same applies for any shift operation (normalize, shift left/right). The error flag is set if the user’s
program reads one of the relevant registers (MD0 to MD3) or if it writes to MD0 again before the
shift operation has been completed.
Please note that the error flag mechanism is just an option to monitor the MDU operation. lf the
user’s program is designed such that an MDU operation cannot be interrupted by other calculations,
then there is no need to pay attention to the error flag. In this case it is also possible to change the
order in which the MDx registers are read, or even to skip some register read instructions.
Concerning the shift or normalize instructions, it is possible to read the result before the complete
execution time of six machine cycles has passed (e.g. when a small number of shifts has been
programmed). All of the above “illegal” actions would set the error flag, but on the other hand do not
affect a correct MDU operation. The user has just to make sure that everything goes right.
The error flag (MDEF) is located in ARCON and can be read only. It is automatically cleared after
being read.
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6.5
Serial Interfaces
The C509-L has two serial interfaces which are functionally nearly identical concerning the
asynchronous modes of operation. The two channels are full-duplex, meaning they can transmit
and receive simultaneously. They are also receive buffered, meaning they can commence
reception of a second byte before a previously received byte has been read from the receive
register (however, if the first byte still has not been read by the time reception of the second byte is
complete, the last received byte will be lost). The serial channel 0 is completely compatible with the
serial channel of the C501. Serial channel 1 has the same functionality in its asynchronous modes,
but the synchronous mode is missing.
6.5.1
Serial Interface 0
6.5.1.1
Operating Modes of Serial Interface 0
The serial interface 0 can operate in four modes (one synchronous mode, three asynchronous
modes). The baud rate clock for this interface is derived from the oscillator frequency (mode 0, 2)
or generated either by timer 1 or by a dedicated baud rate generator (mode 1, 3). A more detailed
description of how to set the baud rate will follow in section 6.5.1.3.
Mode 0: Shift register (synchronous) mode:
Serial data enters and exits through RXD0. TXD0 outputs the shift clock. 8 data bits are
transmitted/received (LSB first). The baud rate is fixed at 1/6 of the oscillator frequency.
Mode 1: 8-bit UART, variable baud rate:
10 bits are transmitted (through TXD0) or received (through RXD0): a start bit (0), 8 data bits (LSB
first), and a stop bit (1). On reception, the stop bit goes into RB80 in special function register
S0CON. The baud rate is variable.
Mode 2: 9-bit UART, fixed baud rate:
11 bits are transmitted (through TXD0) or received (through RXD0): a start bit (0), 8 data bits (LSB
first), a programmable 9th bit, and a stop bit (1). On transmission, the 9th data bit (TB80 in S0CON)
can be assigned to the value of 0 or 1. For example, the parity bit (P in the PSW) could be moved
into TB80 or a second stop bit by setting TB80 to 1. On reception the 9th data bit goes into RB80
in special function register S0CON, while the stop bit is ignored. The baud rate is programmable to
either 1/16 or 1/32 of the oscillator frequency.
Mode 3: 9-bit UART, variable baud rate:
11 bits are transmitted (through TXD0) or received (through RXD0): a start bit (0), 8 data bits (LSB
first), a programmable 9th bit, and a stop bit (1). On transmission, the 9th data bit (TB80 in S0CON)
can be assigned to the value of 0 or 1. For example, the parity bit (P in the PSW) could be moved
into TB80 or a second stop bit by setting TB80 to 1. On reception, the 9th data bit goes into RB80
in special function register S0CON, while the stop bit is ignored. In fact, mode 3 is the same as
mode 2 in all respects except the baud rate. The baud rate in mode 3 is variable.
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In all four modes, transmission is initiated by any instruction that uses S0BUF as a destination
register. Reception is initiated in mode 0 by the condition RI0 = 0 and REN0 = 1. Reception is
initiated in the other modes by the incoming start bit if REN0 = 1. The serial interfaces also provide
interrupt requests when a transmission or a reception of a frame has completed. The corresponding
interrupt request flags for serial interface 0 are TI0 or RI0, resp. See chapter 7 of this user manual
for more details about the interrupt structure. The interrupt request flags TI0 and RI0 can also be
used for polling the serial interface 0 if the serial interrupt is not to be used (i.e. serial interrupt 0 not
enabled).
The control and status bits of the serial interface 0 are located in special function register S0CON.
S0BUF is the receive and transmit buffer of serial interface 0. Writing to S0BUF loads the transmit
register and initiates transmission. Reading out S0BUF accesses a physically separate receive
register.
6.5.1.2
Multiprocessor Communication Feature
Modes 2 and 3 of the serial interface 0 have a special provision for multi-processor communication.
In these modes, 9 data bits are received. The 9th bit goes into RB80. Then a stop bit follows. The
port can be programmed such that when the stop bit is received, the serial port 0 interrupt will be
activated (i.e. the request flag RI0 is set) only if RB80 = 1. This feature is enabled by setting bit
SM20 in S0CON. A way to use this feature in multiprocessor communications is as follows.
lf the master processor wants to transmit a block of data to one of the several slaves, it first sends
out an address byte which identifies the target slave. An address byte differs from a data byte in
that the 9th bit is 1 in an address byte and 0 in a data byte. With SM20 = 1, no slave will be
interrupted by a data byte. An address byte, however, will interrupt all slaves, so that each slave
can examine the received byte and see if it is being addressed. The addressed slave will clear its
SM20 bit and prepare to receive the data bytes that will be coming. After having received a complete
message, the slave sets SM20 again. The slaves that were not addressed leave their SM20 set and
go on about their business, ignoring the incoming data bytes.
SM20 has no effect in mode 0. In mode 1 SM20 can be used to check the validity of the stop bit. lf
SM20 = 1 in mode 1, the receive interrupt will not be activated unless a valid stop bit is received.
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Special Function Register S0CON (Address 98H)
Special Function Register S0BUF (Address 99H)
Bit No.
98H
Reset Value : 00H
Reset Value : XXH
MSB
LSB
9FH
9EH
9DH
9CH
9BH
9AH
99H
98H
SM0
SM1
SM20
REN0
TB80
RB80
TI0
RI0
1
0
7
6
5
4
3
2
Serial Interface 0 Buffer Register
99H
Bit
Function
SM0
SM1
Serial port 0 mode selection bits
S0CON
S0BUF
SM0
SM1
Selected operating mode
0
0
Serial mode 0 : Shift register, fixed baud rate (fOSC/6)
0
1
Serial mode 1 : 8-bit UART, variable baud rate
1
0
Serial mode 2 : 9-bit UART, fixed baud rate (fOSC/16 or fOSC/32)
1
1
Serial mode 3 : 9-bit UART, variable baud rate
SM20
Enable serial port 0 multiprocessor communication in modes 2 and 3
In mode 2 or 3, if SM2 is set to 1 then RI0 will not be activated if the received 9th
data bit (RB8) is 0. In mode 1, if SM2 = 1 then RI0 will not be activated if a valid
stop bit was not received. In mode 0, SM2 should be 0.
REN0
Enable receiver of serial port 0
Enables serial reception. Set by software to enable serial reception. Cleared by
software to disable serial reception.
TB80
Serial port 0 transmitter bit 9
TB80 Is the 9th data bit that will be transmitted in modes 2 and 3. Set or cleared
by software as desired.
RB80
Serial port 0 receiver bit 9
In modes 2 and 3, RB80 is the 9th data bit that was received. In mode 1, if
SM2 = 0, RB80 is the stop bit that was received. In mode 0, RB80 is not used.
TI0
Serial port 0 transmitter interrupt flag
TI0 is set by hardware at the end of the 8th bit time in mode 0, or at the beginning
of the stop bit in the other modes, in any serial transmission. TI0 must be cleared
by software.
RI0
Serial port 0 receiver interrupt flag
RI0 is set by hardware at the end of the 8th bit time in mode 0, or halfway through
the stop bit time in the other modes, in any serial reception (exception see SM20).
RI0 must be cleared by software.
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6.5.1.3
Baud Rates of Serial Channel 0
There are several possibilities to generate the baud rate clock for the serial interface 0 depending
on the mode in which it is operated.
For clarification some terms regarding the difference between “baud rate clock” and “baud rate”
should be mentioned. The serial interface requires a clock rate which is 16 times the baud rate for
internal synchronization. Therefore, the baud rate generators have to provide a “baud rate clock” to
the serial interface which - there divided by 16 - results in the actual “baud rate”. However, all
formulas given in the following section already include the factor and calculate the final baud rate.
Further, the abbreviation fOSC refers to the oscillator frequency (crystal or external clock operation).
The baud rate of the serial channel 0 is controlled by several bits which are located in the special
function registers as shown below.
Special Function Register ADCON0 (Address D8H)
Special Function Register PCON (Address 87H)
Special Function Register PRSC (Address B4H)
Bit No.
D8H
87H
B4H
Reset Value : 00H
Reset Value : 00H
Reset Value : 11010101B
MSB
DFH
DEH
DDH
DCH
DBH
DAH
D9H
LSB
D8H
BD
CLK
ADEX
BSY
ADM
MX2
MX1
MX0
7
6
5
4
3
2
1
0
SMOD
PDS
IDLS
SD
GF1
GF0
PDE
IDLE
7
6
5
4
3
2
1
0
WDTP
S0P
T2P1
T2P0
T1P1
T1P2
T0P1
T0P0
ADCON0
PCON
PRSC
The shaded bits are not used in controlling serial interface 0.
Bit
Function
BD
Baud rate generator enable
When set, the baud rate of serial interface 0 is derived from a dedicated baud rate
generator. When cleared (default after reset), baud rate is derived from the timer
1 overflow rate.
SMOD
Double baud rate
When set, the baud rate of serial interface 0 in modes 1, 2, 3 is doubled. After
reset this bit is cleared.
S0P
Serial interface 0 prescaler
When set (default after reset), an additional prescaler by 2 is active at the
dedicated baud rate generator.
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Figure 6-38 shows the configuration for the baud rate generation of serial channel 0.
Figure 6-38
Baud Rate Generation for Serial Channel 0
Depending on the programmed operating mode different paths are selected for the baud rate clock
generation. Table 6-12 shows the dependencies of the serial port 0 baud rate clock generation from
the 3 control bits and from the mode which is selected in the special function register S0CON.
Table 6-12
Serial Interface 0 - Baud Rate Dependencies
Serial Interface 0
Operating Modes
Active Control Bits
Baud Rate Clock Generation
BD
S0P
SMOD
Mode 0 (Shift Register)
–
–
–
Fixed baud rate clock fosc/6
Mode 1 (8-bit UART)
Mode 3 (9-bit UART)
X
X
X
BD=0: Timer 1 overflow is used for
baud rate generation; SMOD
controls a divide-by-2 option.
BD=1: Baud rate generator is used for
rate generation; S0P and
SMOD control two divide-by-2
options.
Mode 2 (9-bit UART)
–
–
X
Fixed baud rate clock fosc/16
(SMOD=1) or fosc/32 (SMOD=0)
Note: If the internal baud generator is selected in mode 1,3, S0P has no effect on the prescaler function if the
reload value in S0RELL/S0RELH is 3FFH (S0P divider ratio of ÷1 implicitly selected).
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Baud Rate in Mode 0
The baud rate in mode 0 is fixed to:
Mode 0 baud rate =
oscillator frequency
6
Baud Rate in Mode 2
The baud rate in mode 2 depends on the value of bit SMOD in special function register PCON. If
SMOD = 0 (which is the value after reset), the baud rate is 1/32 of the oscillator frequency.
If SMOD = 1, the baud rate is 1/16 of the oscillator frequency.
Mode 2 baud rate =
2 SMOD
32
x oscillator frequency
Baud Rate in Mode 1 and 3
In these modes the baud rate is variable and can be generated alternatively by a baud rate
generator or by timer 1.
Using the baud rate generator:
In modes 1 and 3, the C509-L can use an internal baud rate generator for serial interface 0. To
enable this feature, bit BD (bit 7 of special function register ADCON0) must be set. Bit S0P
(PRSC.6) and SMOD (PCON.7) control divide-by-2 circuits which affect the input and output clock
signal of the baud rate generator. After reset both divide-by-2 circuits are active. So, the input clock
of the baud rate generator is fOSC/2 and the resulting overflow output clock will be divided by 2.
Figure 6-39
Serial Interface 0 Input Clock using the Baud Rate Generator
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The baud rate generator consists of a free running upward counting 10-bit timer. On overflow of this
timer (next count step after counter value 3FFH) there is an automatic 10-bit reload from the
registers S0RELL and S0RELH. The lower 8 bits of the timer are reloaded from S0RELL, while the
upper two bits are reloaded from bit 0 and 1 of register S0RELH. The baud rate timer is reloaded
by writing to S0RELL.
Special Function Register S0RELH (Address BAH)
Special Function Register S0RELL (Address AAH)
Bit No.
BAH
AAH
Reset Value : XXXXXX11B
Reset Value : D9H
MSB
LSB
7
6
5
4
3
2
1
0
–
–
–
–
–
–
MSB
.0
7
6
5
4
3
2
1
0
.7
.6
.5
.4
.3
.2
.1
LSB
Bit
Function
S0RELH.0-1
Reload value. Upper two bits of the timer reload value.
S0RELL.0-7
Reload value. Lower 8 bit of timer reload value.
S0RELH
S0RELL
After reset S0RELH and S0RELL have a reload value of 3D9H. With this reload value the baud rate
generator has an overflow rate of input clock / 39. With a 12-MHz oscillator frequency, the
commonly used baud rates 4800 baud (SMOD = 0) and 9600 baud (SMOD = 1) are available (with
0.16 % deviation).
With the baud rate generator as clock source for the serial port 0 in mode 1 and 3, the baud rate of
can be determined as follows:
Mode 1, 3 baud rate =
2 SMOD x oscillator frequency
64 x (baud rate generator overflow rate) x 2S0P
Baud rate generator overflow rate = 210 – S0REL
with S0REL = S0RELH.1 – 0, S0RELL.7 – 0
At 12-MHz oscillator frequency a baud rate range from about 92 baud up to 375 kbaud is covered.
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Using timer 1 to generate baud rates:
In mode 1 and 3 of serial interface 0 timer 1 can be used for generating baud rates. Then the baud
rate is determined by the timer 1 overflow rate and the value of SMOD as follows:
Mode 1, 3 baud rate =
2SMOD
32
x (timer 1 overflow rate)
The timer 1 interrupt is usually disabled in this application. Timer 1 itself can be configured for either
“timer” or “counter” operation, and in any of its operating modes. In most typical applications, it is
configured for “timer” operation in the auto-reload mode (high nibble of TMOD = 0010 B). In this
case the baud rate is given by the formula:
2SMOD x oscillator frequency
Mode 1, 3 baud rate =
32 x 6 x PRSC x (256 – (TH1))
PRSC is the prescaler ratio
which is selected via the bits
T1P1 and T1P0 in the special
function register PRSC.
Timer 1 Prescaler Bits
T1P1
T1P0
PRSC Value in
the forrmula above
0
0
1
0
1
2
1
0
4
1
1
8
Very low baud rates can be achieved with timer 1 if leaving the timer 1 interrupt enabled, configuring
the timer to run as 16-bit timer (high nibble of TMOD = 0001B), and using the timer 1 interrupt for a
16-bit software reload.
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6.5.2
Serial Interface 1
6.5.2.1 Operating Modes of Serial Interface 1
The serial interface 1 is an asynchronous unit only and is able to operate in two modes, as an 8-bit
or 9-bit UART. These modes, however, correspond to the above mentioned modes 1, 2 and 3 of
serial interface 0. The multiprocessor communication feature is identical with this feature in serial
interface 0. The serial interface 1 has its own interrupt request flags Rl1 and Tl1 which have a
dedicated interrupt vector location. The baud rate clock for this interface is generated by a
dedicated baud rate generator.
Mode A: 9-bit UART, variable baud rate:
11 bits are transmitted (through TXD1) or received (through RXD1): a start bit (0), 8 data bits (LSB
first), a programmable 9th bit, and a stop bit (1). On transmission, the 9th data bit (TB81 in S1CON)
can be assigned to the value of 0 or 1. For example, the parity bit (P in the PSW) could be moved
into TB81 or a second stop bit by setting TB81 to 1. On reception the 9th data bit goes into RB81
in special function register S0CON, while the stop bit is ignored. In fact, mode A of serial interface
1 is identical with mode 2 or 3 of serial interface 0 in all respects except the baud rate generation.
Mode B: 8-bit UART, variable baud rate:
10 bits are transmitted (through TXD1) or received (through RXD1): a start bit (0), 8 data bits (LSB
first), and a stop bit (1). On reception, the stop bit goes into RB81 in special function register
S1CON. In fact, mode B of serial interface 1 is identical with mode 1 of serial interface 0 in all
respects except for the baud rate generation.
In both modes, transmission is initiated by any instruction that uses S1BUF as a destination
register. Reception is initiated by the incoming start bit if REN1 = 1. The serial interfaces also
provide interrupt requests when a transmission or a reception of a frame has completed. The
corresponding interrupt request flags for serial interface 1 are Tl1 or Rl1, respectively. The interrupt
request flags Tl1 and Rl1 can also be used for polling the serial interface 1 if the serial interrupt shall
not be used (i.e. serial interrupt 1 not enabled).
The control and status bits of the serial channel 1 in special function register S1CON and the
transmit/receive data register S1BUF are shown on the next page. Writing to S1BUF loads the
transmit register and initiates transmission. Reading out S1BUF accesses a physically separate
receive register.
Note that these special function registers are not bit-addressable. Due to this fact bit instructions
cannot be used for manipulating these registers. This is important especially for S1CON where a
polling and resetting of the Rl1 or Tl1 request flag cannot be performed by JNB and CLR instructions
but must be done by a sequence of byte instructions, e.g.:
LOOP:
MOV
JNB
ANL
A,S1CON
ACC.0,LOOP
S1CON,#0FEH
Semiconductor Group
;Testing of RI1
;Resetting of RI1
6-90
1997-10-01
On-Chip Peripheral Components
C509-L
Special Function Register S1CON (Address 9BH)
Special Function Register S1BUF (Address 9CH)
Bit No.
9BH
Reset Value : 01000000B
Reset Value : XXH
MSB
LSB
7
6
5
4
3
2
1
0
SM
S1P
SM21
REN1
TB81
RB81
TI1
RI1
7
6
5
4
3
2
1
0
9CH
Serial Interface 1 Buffer Register
S1CON
S1BUF
Bit
Function
SM
Serial port 1 mode select bit
SM = 0: Serial mode A; 9-bit UART
SM = 1: Serial mode B; 8-bit UART
S1P
Serial interface 1 prescaler
When set (default after reset), an additional prescaler by 2 is active at
the serial interface 1 baud rate generator.
SM21
Enable serial port 1 multiprocessor communication in mode A
If SM21 is set to 1 in mode A, RI1 will not be activated if the received 9th
data bit (RB81) is 0. In mode B, if SM21 = 1, RI1 will not be activated if
a valid stop bit was not received.
REN1
Enable receiver of serial port 1
Set by software to enable serial reception. Cleared by software to
disable reception.
TB81
Serial port 1 transmitter bit 9
TB81 is the 9th data bit that will be transmitted in mode A. Set or cleared
by software as desired.
RB81
Serial port 1 receiver bit 9
RB81 is the 9th data bit that was received in mode A. In mode B,
if SM21 = 0, RB81 is the stop bit that was received.
TI1
Serial port 1 transmitter interrupt flag
TI1 is set by hardware at the beginning of the stop bit in any serial
transmission. TI1 must be cleared by software.
RI1
Serial port 1 receiver interrupt flag
RI1 is set by hardware at the halfway through the stop bit time in any
serial reception. RI1 must be cleared by software.
Semiconductor Group
6-91
1997-10-01
On-Chip Peripheral Components
C509-L
6.5.2.2 Multiprocessor Communication Feature
Mode A of the serial interface 1 has a special provision for multiprocessor communication. In this
mode, 9 data bits are received. The 9th bit goes into RB81. Then a stop bit follows. The port can be
programmed such that when the stop bit is received, the serial port 1 interrupt will be activated (i.e.
the request flag Rl1 is set) only if RB81 = 1. This feature is enabled by setting bit SM21 in S1CON.
A way to use this feature in multiprocessor communications is as follows.
lf the master processor wants to transmit a block of data to one of the several slaves, it first sends
out an address byte which identifies the target slave. An address byte differs from a data byte in
that the 9th bit is 1 in an address byte and 0 in a data byte. With SM21 = 1, no slave will be
interrupted by a data byte. An address byte, however, will interrupt all slaves, so that each slave
can examine the received byte and see if it is being addressed. The addressed slave will clear its
SM21 bit and prepare to receive the data bytes that will be coming. After having received a complete
message, the slave is setting SM21 again. The slaves that were not addressed leave their SM21
set and go on about their business, ignoring the incoming data bytes.
In mode B, SM21 can be used to check the validity of the stop bit. lf SM21 = 1 in mode B, the receive
interrupt will not be activated unless a valid stop bit is received.
6.5.2.3 Baud Rates of Serial Channel 1
As already mentioned serial interface 1 uses its own dedicated baud rate generator for baud rate
generation in both operating modes (see figure 6-40). This baud rate generator consists of a free
running 10-bit timer with fOSC/2 (S1P=1) or fOSC (S1P=0) as input frequency. On overflow of this
timer (next count step after counter value 3FFH) there is an automatic 10-bit reload from the
registers S1RELL and S1RELH. The lower 8 bits of the timer are reloaded from S1RELL, while the
upper two bits are reloaded from bit 0 and 1 of register S1RELH. The baud rate timer is reloaded
by writing to S1RELL.
Figure 6-40
Baud Rate Generator for Serial Interface 1
Semiconductor Group
6-92
1997-10-01
On-Chip Peripheral Components
C509-L
Special Function Register S1RELH (Address BBH)
Special Function Register S1RELL (Address 9DH)
Bit No.
BBH
9DH
Reset Value : XXXXXX11B
Reset Value : 00H
MSB
LSB
7
6
5
4
3
2
1
0
–
–
–
–
–
–
MSB
.0
7
6
5
4
3
2
1
0
.7
.6
.5
.4
.3
.2
.1
LSB
Bit
Function
S1RELH.0-1
Reload value. Upper two bits of the timer reload value.
S1RELL.0-7
Reload value. Lower 8 bit of timer reload value.
S1RELH
S1RELL
The baud rate in operating modes A and B can be determined by following formula:
Mode A, B baud rate =
oscillator frequency
32 x (baud rate generator overflow rate) x 2S1P
Baud rate generator overflow rate = 210 – S1REL
with S1REL = S1RELH.1 – 0, S1RELL.7 – 0
At 12-MHz oscillator frequency a baud rate range from about 366 baud up to 750 kbaud is covered.
Semiconductor Group
6-93
1997-10-01
On-Chip Peripheral Components
C509-L
6.5.3
Detailed Description of the Operating Modes
The following sections give a more detailed description of the several operating modes of the two
serial interfaces.
6.5.3.1 Mode 0, Synchronous Mode (Serial Interface 0)
Serial data enters and exits through RXD0. TXD0 outputs the shift clock. 8 data bits are
transmitted/received (LSB first). The baud rate is fixed at 1/6 of the oscillator frequency.
Figure 6-41a shows a simplified functional diagram of the serial port in mode 0. The associated
timing is illustrated in figure 2-42b.
Transmission is initiated by any instruction that uses S0BUF as a destination register. The “Writeto-S0BUF” signal at S6P2 also loads a 1 into the 9th bit position of the transmit shift register and
tells the TX control block to commence a transmission. The internal timing is such that one full
machine cycle will elapse between “Write-to-S0BUF” and activation of SEND.
SEND enables the output of the shift register to the alternate output function line P3.0, and also
enables SHIFT CLOCK to the alternate output function line P3.1. SHIFT CLOCK is low during S3,
S4, and S5 of every machine cycle, and high during S6, S1, and S2, while the interface is
transmitting. Before and after transmission SHIFT CLOCK remains high. At S6P2 of every machine
cycle in which SEND is active, the contents of the transmit shift register is shifted one position to
the right.
As data bits shift out to the right, zeros come in from the left. When the MSB of the data byte is at
the output position of the shift register, then the 1 that was initially loaded into the 9th position, is
just left of the MSB, and all positions to the left of that contain zeros. This condition flags the TX
control block to do one last shift and then deactivates SEND and sets TI0. Both of these actions
occur at S1P1 in the 10th machine cycle after “Write-to-S0BUF”.
Reception is initiated by the condition REN0 = 1 and RI0 = 0. At S6P2 in the next machine cycle,
the RX control unit writes the bits 1111 1110 to the receive shift register, and in the next clock phase
activates RECEIVE.
RECEIVE enables SHIFT CLOCK to the alternate output function line of P3.1. SHIFT CLOCK
makes transitions at S3P1 and S6P1 in every machine cycle. At S6P2 of every machine cycle in
which RECEIVE is active, the contents of the receive shift register are shifted one position to the
left. The value that comes in from the right is the value that was sampled at the P3.0 pin at S5P2 in
the same machine cycle.
As data bits come in from the right, 1 s shift out to the left. When the 0 that was initially loaded into
the rightmost position arrives at the leftmost position in the shift register, it flags the RX control block
to do one last shift and load S0BUF. At S1P1 in the 10th machine cycle after the write to S0CON
that cleared RI0, RECEIVE is cleared and RI0 is set.
Semiconductor Group
6-94
1997-10-01
On-Chip Peripheral Components
C509-L
Internal Bus
1
Write
to
S0BUF
Q
S
&
S0BUF
D
RXD0
P3.0 Alt.
Output
Function
Q
CLK
Zero Detector
Shift
Start
Shift
TX Control
S6
TX Clock
Tl0
Serial
Port
Interrupt
REN0
1
1
&
TXD0
P3.1 Alt.
Output
Function
Shift
Clock
&
RI0
Send
Rl0
Start
Receive
RX Control
RX Clock
1 1 1 1 1 1 1 0 Shift
Input Shift Register
Shift
Load
S0BUF
RXD0
P3.0 Alt.
Input
Function
S0BUF
Read
S0BUF
Internal Bus
MCS01831
Figure 6-41
Functional Diagram - Serial Interface 0, Mode 0
Semiconductor Group
6-95
1997-10-01
Semiconductor Group
6-96
TXD0
(Shift Clock)
RXD0
(Data In)
S5P2
D0
Write to S0CON (Clear RI)
D1
D1
D2
D2
D3
D3
D4
D4
D5
D5
D6
D6
D7
D7
MCT01832
Transmit
Shift
Receive
RIO
TIO
TXD0
(Shift Clock)
D0
S3P1 S6P1
Write to S0BUF
S6P2
RXD0
(Data Out)
Shift
Send
ALE
SSSSSS SSSSSS SSSSSS SSSSSS SSSSSS SSSSSS SSSSSS SSSSSS SSSSSS SSSSSS
123456 123456 123456 123456 123456 123456 123456 123456 123456 123456
On-Chip Peripheral Components
C509-L
Receive
Figure 6-42
Timing Diagram - Serial Interface 0, Mode 0
1997-10-01
On-Chip Peripheral Components
C509-L
6.5.3.2
Mode 1/Mode B, 8-Bit UART (Serial Interfaces 0 and 1)
Ten bits are transmitted (through TXD0 or TXD1), or received (through RXD0 or RXD1): a start bit
(0), 8 data bits (LSB first), and a stop bit (1). On reception through RXD0, the stop bit goes into RB80
(S0CON), on reception through RXD1, RB81 (S1C0N) stores the stop bit.
The baud rate for serial interface 0 is determined by the timer 1 overflow rate or by the internal baud
rate generator of serial interface 0. Serial interface 1 receives the baud rate clock from its own baud
rate generator.
Figure 6-43a shows a simplified functional diagram of the both serial channels in mode 1 or
mode B, respectively. The associated timing is illustrated in figure 2-44b.
Transmission is initiated by any instruction that uses S0BUF/S1BUF as a destination register. The
“write-to-S0BUF/S1BUF” signal also loads a 1 into the 9th bit position of the transmit shift register
and flags the TX control block that a transmission is requested. Transmission actually commences
at S1P1 of the machine cycle following the next roll-over in the divide-by-16 counter (thus, the bit
times are synchronized to the divide-by-16 counter, not to the “write-to-S0BUF/S1BUF” signal).
The transmission begins with activation of SEND, which puts the start bit to TXD0/TXD1. One bit
time later, DATA is activated, which enables the output bit of the transmit shift register to
TXD0/TXD1. The first shift pulse occurs one bit time after that.
As data bits shift out to the right, zeros are clocked in from the left. When the MSB of the data byte
is at the output position of the shift register, then the 1 that was initially loaded into the 9th position
is just left of the MSB, and all positions to the left of that contain zero. This condition flags the TX
control to do one last shift and then deactivate SEND and set TI0/Tl1. This occurs at the 10th divideby-16 rollover after “write-to-S0BUF/S1BUF”.
Reception is initiated by a detected 1-to-0 transition at RXD0/RXD1. For this purpose RXD0/RXD1
is sampled at a rate of 16 times whatever baud rate has been established. When a reception is
detected, the divide-by-16 counter is immediately reset, and 1FFH is written into the input shift
register.
The 16 states of the counter divide each bit time into 16 counter states. At the 7th, 8th and 9th
counter state of each bit time, the bit detector samples the value of RXD0/RXD1. The value
accepted is the value that was seen in at least 2 of the 3 samples. This is done for noise rejection.
lf the value accepted during the first bit time is not 0, the receive circuits are reset and the unit goes
back looking for another 1-to-0 transition. This is to provide rejection of false start bits. lf the start bit
proves valid, it is shifted into the input shift register, and reception of the rest of the frame will
proceed.
As data bits come from the right, 1’s shift out to the left. When the start bit arrives at the leftmost
position in the shift register (which in mode 1/B is a 9-bit register), it flags the RX control block to do
one last shift. The signal to load S0BUF/S1BUF and RB80/RB81, and to set RI0/Rl1 will be
generated if, and only if, the following conditions are met at the time the final shift pulse is
generated:
1)
2)
RI0/Rl1 = 0, and
either SM20/SM21 = 0 or the received stop bit = 1
lf either of these two conditions is not met the received frame is irretrievably lost. lf both conditions
are met, the stop bit goes into RB80/RB81, the 8 data bits go into S0BUF/S1BUF, and RI0/Rl1 is
activated. At this time, no matter whether the above conditions are met or not, the unit goes back
to looking for a 1-to-0 transition in RxD0/RxD1.
Semiconductor Group
6-97
1997-10-01
On-Chip Peripheral Components
C509-L
Internal Bus
1
Write
to
SxBUF
S
Q
&
SxBUF
<_ 1
TXDx
D
Q
CLK
Zero Detector
Shift
Start
Data
TX Control
÷ 16
TX Clock
Baud
Rate
Clock
Serial
Port
Interrupt
Tlx
Send
Rlx
Load
SxBUF
<_ 1
÷ 16
Sample
1-to-0
Transition
Detector
RX Clock
RX Control
Start
1FF H Shift
Bit
Detector
Input Shift Register
(9Bits)
RXDx
Shift
Load
SxBUF
Note: x means that 0 or 1 can
be inserted for interface
0 or interface 1, resp.
SxBUF
Read
SxBUF
Internal Bus
MCS01833
Figure 6-43
Functional Diagram - Serial Interfaces 0 and 1, Mode 1 / Mode B
Semiconductor Group
6-98
1997-10-01
Semiconductor Group
TI
TXD
Shift
Data
Send
6-99
D0
Start Bit
..-16 RESET
Start Bit
S1P1
D0
D1
D1
D2
D2
D3
D3
D4
D4
D5
D5
D6
D6
D7
D7
Stop Bit
Stop Bit
MCT01936
Transmit
Note : x=0 for serial interface 0 and x=1 for serial interface 1.
RI
Shift
Bit Detector
Sample Times
RXD
RX Clock
Write
to SBUF
TX Clock
On-Chip Peripheral Components
C509-L
Receive
Figure 6-44
Timing Diagram - Serial Interfaces 0 and 1, Mode 1 / Mode B
1997-10-01
On-Chip Peripheral Components
C509-L
6.5.3.3
Mode 2, 9-Bit UART (Serial Interface 0)
Mode 2 is functionally identical to mode 3 (see below). The only exception is, that in mode 2 the
baud rate can be programmed to two fixed quantities: either 1/16 or 1/32 of the oscillator frequency.
Note that serial interface 0 cannot achieve this baud rate in mode 3. Its baud rate clock is generated
by timer 1, which is incremented by a rate of fOSC/6. The dedicated baud rate generator of serial
interface 1 however is clocked by a fOSC signal and so its maximum baud rate is fOSC/16.
6.5.3.4
Mode 3 / Mode A, 9-Bit UART (Serial Interfaces 0 and 1)
Eleven bits are transmitted (through TXD0/TXD1), or received (through RXD0/RXD1): a start bit (0),
8 data bits (LSB first), a programmable 9th data bit, and a stop bit (1). On transmission, the 9th data
bit (TB80/TB81) can be assigned the value of 0 or 1. On reception the 9th data bit goes into
RB80/RB81 in S0CON/S1CON. Mode 3 may have a variable baud rate generated from either timer
1 or 2 depending on the state of TCLK and RCLK in SFR T2CON.
Figure 6-45a shows a simplified functional diagram of the both serial channels in mode 2 an 3 or
mode A, respectively. The associated timing is illustrated in figure 6-46b. The receive portion is
exactly the same as in mode 1. The transmit portion differs from mode 1 only in the 9th bit of the
transmit shift register.
Transmission is initiated by any instruction that uses S0BUF/S1BUF as a destination register. The
“write to S0BUF/S1BUF” signal also loads TB80/TB81 into the 9th bit position of the transmit shift
register and flags the TX control unit that a transmission is requested. Transmission commences at
S1P1 of the machine cycle following the next rollover in the divide-by-16 counter (thus the bit times
are synchronized to the divide-by-16 counter, and not to the “write-to-S0BUF/S1BUF” signal).
The transmission begins with the activation of SEND, which puts the start bit to TXD0/TXD1. One
bit time later, DATA is activated which enables the output bit of transmit shift register to TXD0/TXD1.
The first shift pulse occurs one bit time after that. The first shift clocks a 1 (the stop bit) into the 9th
bit position of the shift register. Thereafter, only zeros are clocked in. Thus, as data shift out to the
right, zeros are clocked in from the left. When TB80/TB81 is at the output position of the shift
register, then the stop bit is just left of the TB80/TB81, and all positions to the left of that contain
zeros.
This condition flags the TX control unit to do one last shift and then deactivate SEND and set
TI0/TI1. This occurs at the 11th divide-by-16 rollover after “write-to-S0BUF/S1BUF”.
Reception is initiated by a detected 1-to-0 transition at RXD0/RXD1. For this purpose RXD0/RXD1
is sampled of a rate of 16 times whatever baud rate has been established. When a transition is
detected, the divide-by-16 counter is immediately reset, and 1FFH is written to the input shift
register.
At the 7th, 8th and 9th counter state of each bit time, the bit detector samples the value of
RxD0/RxD1. The value accepted is the value that was seen in at least 2 of the 3 samples. lf the
value accepted during the first bit time is not 0, the receive circuits are reset and the unit goes back
to looking for another 1-to-0 transition. lf the start bit proves valid, it is shifted into the input shift
register, and reception of the rest of the frame will proceed.
As data bits come from the right, 1’s shift out to the left. When the start bit arrives at the leftmost
position in the shift register (which is a 9-bit register), it flags the RX control block to do one last shift,
load S0BUF/S1BUF and RB80/ RB81, and set RI0/RI1. The signal to load S0BUF/S1BUF and
Semiconductor Group
6-100
1997-10-01
On-Chip Peripheral Components
C509-L
RB80/RB81, and to set RI0/RI1, will be generated if, and only if, the following conditions are met at
the time the final shift pulse is generated:
1) RI0/RI1 = 0, and
2) either SM20/SM21 = 0 or the received 9th data bit = 1
lf either one of these two conditions is not met, the received frame is irretrievably lost, and RI0/Rl1
is not set. lf both conditions are met, the received 9th data bit goes into RB80/RB81, the first 8 data
bits go into S0BUF/S1BUF. One bit time later, no matter whether the above conditions are met or
not, the unit goes back to look for a 1-to-0 transition at the RXD0/RXD1 input.
Note that the value of the received stop bit is irrelevant to S0BUF/S1BUF, RB80/RB81, or RI0/Rl1.
Semiconductor Group
6-101
1997-10-01
On-Chip Peripheral Components
C509-L
Internal Bus
TB8x
Write
to
SxBUF
S
Q
&
SxBUF
<_ 1
TXDx
D
Q
CLK
Zero Detector
Shift
Start
Data
TX Control
÷ 16
TX Clock
Baud
Rate
Clock
Serial
Port
Interrupt
Tlx
Send
Rlx
Load
SxBUF
<_ 1
÷ 16
Sample
1-to-0
Transition
Detector
RX Clock
RX Control
Start
1FF H Shift
Bit
Detector
Input Shift Register
(9Bits)
RXDx
Shift
Load
SxBUF
Note: x means that 0 or 1 can
be inserted for interface
0 or interface 1, resp.
SxBUF
Read
SxBUF
Internal Bus
MCS01834
Figure 6-45
Functional Diagram - Serial Interfaces 0 and 1, Modes 2 and 3 / Mode A
Semiconductor Group
6-102
1997-10-01
Write
to SxBUF
Mode 2: S6P1
Mode 3: S1P1
Send
S1P1
Data
Transmit
6-103
Shift
D0
Start Bit
TXD
D1
D2
D3
D4
D5
D6
D7
TB8
Stop Bit
TI
Stop Bit Gen.
RX Clock
RXDx
Start Bit
D0
D1
D2
D3
D4
D5
D6
D7
RB8
Stop Bit
Bit Detector
Sample Times
Shift
RIx
1997-10-01
MCT01836
Note : x=0 for serial interface 0 and x=1 for serial interface 1.
On-Chip Peripheral Components
C509-L
-: 16- RESET
Receive
Figure 6-46
Timing Diagram - Serial Interfaces 0 and 1, Modes 2 and 3 / Mode A
Semiconductor Group
TX Clock
On-Chip Peripheral Components
C509-L
6.6
A/D Converter
The C509-L includes a high performance / high speed 10-bit A/D-Converter (ADC) with 15 analog
input channels. This A/D converter operates with a successive approximation technique and uses
self calibration mechanisms for reduction and compensation of offset and linearity errors. The A/D
converter provides the following features:
–
–
–
–
–
–
–
–
15 multiplexed input channels, which can also be used as digital inputs (port 7, port 8)
10-bit resolution
Single or continuous conversion mode
Internal or external start-of-conversion trigger capability
Programmable conversion and sample clock
Interrupt request generation after each conversion
Using successive approximation conversion technique via a capacitor array
Built-in hidden calibration of offset and linearity errors
For the conversion, the method of successive approximation via capacitor array is used. The
externally applied reference voltage range has to be held on a fixed value within the specifications.
Figure 6-47 shows a block diagram of the A/D converter. There are four user-accessible special
function registers, ADCON1/ADCON0 (A/D converter control registers) and ADDATH/ADDATL
(A/D converter data registers). The analog input channels (port 7 and port 8) can also be used for
digital input. For interrupt processing of the A/D converter, two bits are located in the special
function registers IEN2 and IRCON0.
6.6.1 A/D Converter Operation
An internal start of a single A/D conversion is triggered by a write-to-ADDATL instruction. The start
procedure itself is independent of the value which is written to ADDATL. When single conversion
mode is selected (bit ADM=0) only one A/D conversion is performed. In continuous mode (bit
ADM=1), after completion of an A/D conversion a new A/D conversion is triggered automatically
until bit ADM is reset.
An externally controlled conversion can be achieved by setting the bit ADEX. In this mode one
single A/D conversion is triggered by a 1-to-0 transition at pin P6.0/ADST (when ADM is 0).
P6.0/ADST is sampled during S5P2 of every machine cycle. When the samples show a logic high
in one cycle and a logic low in the next cycle the transition is detected and the A/D conversion is
started. When ADM and ADEX is set, a continuous conversion is started when pin P6.0/ADST sees
a low level. Only if no A/D conversion (single or continuous) has occurred after the last reset
operation, a 1-to-0 transition is required at pin P6.0/ADST for starting the continuous conversion
mode externally. The continuous A/D conversion is stopped when the pin P6.0/ADST goes back to
high level. The last running A/D conversion during P6.0/ADST low level will be completed.
The busy flag BSY (ADCON0.4) is automatically set when an A/D conversion is in progress. After
completion of the conversion it is reset by hardware. This flag can be read only, a write has no
effect. The interrupt request flag IADC (IRCON0.0) is set when an A/D conversion is completed.
Semiconductor Group
6-104
1997-10-01
On-Chip Peripheral Components
C509-L
Figure 6-47
Block Diagram of the A/D Converter
Semiconductor Group
6-105
1997-10-01
On-Chip Peripheral Components
C509-L
The bits MX0 to MX2 in special function register ADCON0 and the bits MX0 to MX3 in ADCON1 are
used for selection of the analog input channel. The bits MX0 to MX2 are represented in both
registers ADCON0 and ADCON1; however, these bits are present only once. lf all 15 multiplexed
input channels are required register ADCON1 has to be used for channel selection. lt contains the
four-bit field MX0-3 to select one of the 15 input channels, the eight inputs at port 7 and the seven
inputs at port 8. Thus, there are two methods of selecting a channel of port 7 and it does not matter
which is used: If a new channel is selected in ADCON1 the change is automatically done in the
corresponding bits MX0 to MX2 in ADCON0 and vice versa. lf bit MX3 is set, the additional analog
inputs at port 8 are used. MX0-2 then determine which channel of port 8 is being selected.
Ports P7 and P8 are dual purpose input ports. lf the input voltage meets the specified logic levels,
they can be also used as digital inputs regardless of whether the pin levels are sampled by the A/D
converter at the same time.
The special function register ADDATH and ADDATL hold the converted digital 10-bit data result.
The data remains in ADDAT until it is overwritten by the next converted data. ADDAT can be read
or written under software control. lf the A/D converter of the C509-L is not used, register ADDATH
can be used as an additional general purpose register.
Semiconductor Group
6-106
1997-10-01
On-Chip Peripheral Components
C509-L
6.6.2 A/D Converter Registers
This section describes the bits/functions of all registers which are used by the A/D converter.
Special Function Registers ADDATH (Address D9H)
Special Function Registers ADDATL (Address DAH)
Bit No. MSB
7
MSB
D9H
.9
DAH
.1
Reset Value : 00H
Reset Value : 00H
6
5
4
3
2
1
LSB
0
.8
.7
.6
.5
.4
.3
.2
ADDATH
LSB
.0
–
–
–
–
–
–
ADDATL
The registers ADDATH and ADDATL contain the 10-bit conversion result in left justified data format.
The most significant bit of the 10-bit conversion result is bit 7 of ADDATH. The least significant bit
of the 10-bit conversion result is bit 6 of ADDATL. To get a 10-bit conversion result, both ADDAT
register must be read. If an 8-bit conversion result is required, only the reading of ADDATH is
necessary. The data remains in ADDAT until it is overwritten by the next converted data. ADDAT
can be read or written under software control. lf the A/D converter of the C509-L is not used, register
ADDATH can be used as an additional general purpose register.
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On-Chip Peripheral Components
C509-L
Special Function Registers ADCON0 (Address D8H)
Special Function Registers ADCON1 (Address DCH)
Bit No. MSB
7
D8H
DCH
BD
Reset Value : 00H
Reset Value : 01000000B
LSB
0
6
5
4
3
2
1
CLK
ADEX
BSY
ADM
MX2
MX1
MX0
ADCON0
MX3
MX2
MX1
MX0
ADCON1
ADCL1 ADCL0 ADST1 ADST0
The shaded bits are not used for A/D converter control.
Bit
Function
ADEX
Internal / external start of A/D conversion
When set, the external start of an A/D conversion at pin P6.0/ADST is enabled.
BSY
Busy flag
This flag indicates whether a conversion is in progress (BSY = 1). The flag is
cleared by hardware when the conversion is finished.
ADM
A/D conversion mode
When set, a continuous A/D conversion is selected. If cleared during a running
A/D conversion, the conversion is stopped at its end.
MX3 - MX0
A/D converter input channel select bits
Bits MX3-0 can be written or read either in ADCON0 or ADCON1. When writing
to ADCON1, the ADCON0 bits MX2-0 are overwritten. Writing ADCON0, only
MX2-0 are affected.
The analog inputs are selected according the following table:
MX3
MX2
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
Semiconductor Group
MX1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
MX0
Selected Analog Input
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
P7.0 / AN0
P7.1 / AN1
P7.2 / AN2
P7.3 / AN3
P7.2 / AN4
P7.3 / AN5
P7.4 / AN6
P7.5 / AN7
P8.0 / AN8
P8.1 / AN9
P8.2 / AN10
P8.3 / AN11
P8.4 / AN12
P8.5 / AN13
P8.6 / AN14
6-108
1997-10-01
On-Chip Peripheral Components
C509-L
Bit
Function
ADCL1
ADCL0
A/D conversion clock prescaler selection
ADCL1 and ADCL0 select the prescaler ratio for the A/D conversion clock
fADC. Depending on the clock rate fOSC of the C509-L. fADC must be selected
by the two prescaler bits ADCL1 and ADCL0 in a way that the resulting
frequency of the conversion clock fADC is less or equal 2 MHz.
The prescaler ratio is selected according the following table:
ADST1
ADST0
ADCL1
ADCL0
0
0
1
1
0
1
0
1
f ADC Prescaler Ratio
divide by 4
divide by 8 (default after reset)
divide by 16
divide by 32
A/D sample clock prescaler selection
ADST1 and ADST0 select the prescaler ratio for the sample clock fSC.
The prescaler ratio is selected according the following table:
ADST1
ADST0
0
0
1
1
0
1
0
1
f SC Prescaler Ratio
divide by 2 (default after reset)
divide by 8
divide by 16
divide by 32
Note :Generally, before entering the power-down mode, an A/D conversion in progress must be
stopped. If a single A/D conversion is running, it must be terminated by polling the BSY bit or
waiting for the A/D conversion interrupt. In continuous conversion mode, bit ADM must be
cleared and the last A/D conversion must be terminated before entering the power-down
mode.
A single A/D conversion is started by writing to SFR ADDATL with dummy data. A continuous
conversion is started under the following conditions:
– By setting bit ADM during a running single A/D conversion
– By setting bit ADM when at least one A/D conversion has occurred after the last reset
operation.
– By writing ADDATL with dummy data after bit ADM has been set before (if no A/D conversion
has occurred after the last reset operation).
When bit ADM is reset by software in continuous conversion mode, the just running A/D conversion
is stopped after its end.
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
The A/D converter interrupt is controlled by bits which are located in the SFRs IEN1 and IRCON.
Special Function Register IEN1
(Address B8H)
Special Function Register IRCON0 (Address C0H)
Bit No.
B8H
MSB
BFH
EXEN2 SWDT
C7H
C0H
BEH
EXF2
C6H
TF2
BDH
EX6
C5H
IEX6
BCH
EX5
EX4
C4H
IEX5
BBH
C3H
IEX4
Reset Value : 00H
Reset Value : 00H
BAH
B9H
LSB
B8H
EX3
EX2
EADC
C2H
C1H
C0H
IEX3
IEX2
IADC
IEN1
IRCON0
The shaded bits are not used for A/D converter control.
Bit
Function
EADC
Enable A/D converter interrupt
If EADC = 0, the A/D converter interrupt is disabled
IADC
A/D converter interrupt request flag
Set by hardware at the end of an A/D conversion. Must be cleared by software.
Semiconductor Group
6-110
1997-10-01
On-Chip Peripheral Components
C509-L
6.6.3 A/D Converter Clock Selection
The ADC uses basically three clock signals for operation: the input clock fIN (=1/tIN), the conversion
clock fADC (=1/tADC) and the sample clock fSC (=1/tSC). All clock signals are derived from the
C509-L system clock fOSC which is applied at the XTAL pins. The input clock fIN is equal to fOSC
while the conversion clock and the sample clock must be adapted. The conversion clock is limited
to a maximum frequency of 2 MHz. Therefore, the conversion clock prescaler must be programmed
to a value which assures that the conversion clock does not exceed 2 MHz. The prescaler ratio of
the conversion clock is selected by the bits ADCL1 and ADCL0 of SFR ADCON1. The sample clock
fSC can be adapted to the requirements of the impedance of A/D converter input signal sources.
The prescaler ratio of the sample clock is selected by the bits ADST1 and ADST0 of SFR ADCON1.
Figure 6-48 shows the configuration of the two A/D converter prescalers. The table in figure 6-48
defines the divider ratio for the conversion and sample clock of each combination of the prescaler
bits.
Conversion Clock fADC
Sample Clock fSC
ADCL1 ADCL0 fADC
ADST1 ADST0
0
0
ADST1 ADST0
0
1
ADST1 ADST0
1
0
ADST1 ADST0
1
1
0
0
fIN / 4
fIN / 8
fIN / 16
fIN / 32
fIN / 64
0
1
fIN / 8
fIN / 16
fIN / 32
fIN / 64
fIN / 128
1
0
fIN / 16
fIN / 32
fIN / 64
fIN / 128
fIN / 256
1
1
fIN / 32
fIN / 64
fIN / 128
fIN / 256
fIN / 512
Figure 6-48
A/D Converter Clock Selection
The duration of an A/D conversion is a multiple of the period of the fIN clock signal. The timing of
the A/D conversion and the calculation of an A/D conversion time are shown in the next section.
Semiconductor Group
6-111
1997-10-01
On-Chip Peripheral Components
C509-L
6.6.4
A/D Conversion Timing
An A/D conversion is internally started by writing into the SFR ADDATL with dummy data. A write
to SFR ADDATL will start a new conversion even if a conversion is currently in progress. The
conversion begins with the next machine cycle, and the BSY flag in SFR ADCON0 will be set.
Basically, the A/D conversion procedure is divided into three parts:
– Sample phase (tS), used for sampling the analog input voltage.
– Conversion phase (tCO), used for the real A/D conversion.(includes calibration)
– Write result phase (tWR), used for writing the conversion result into the ADDAT registers.
The total A/D conversion time is defined by tADCC which is the sum of the two phase times tS and
tCO. The duration of the three phases of an A/D conversion is specified by its specific timing
parameter as shown in figure 6-49.
Conversion Clock
Prescaler
Sample Clock
Prescaler
Sample
Time
Conversion
Time
ADST1 ADST0
tS
tCO
ConversionTime
tADCC
CPU Cycles
Tim. Ref
ADCL1
ADCL0
0
0
0
0
1
1
0
1
0
1
8 x tIN
16 x tIN
32 x tIN
64 x tIN
40 x tIN
48 x tIN
56 x tIN
72 x tIN
104 x tIN
8
9
12
17
a)
b)
a)
b)
0
1
0
0
1
1
0
1
0
1
16 x tIN
32 x tIN
64 x tIN
128 x tIN
80 x tIN
96 x tIN
112 x tIN
144 x tIN
208 x tIN
16
18
24
34
a)
c)
a)
c)
1
0
0
0
1
1
0
1
0
1
32 x tIN
64 x tIN
128 x tIN
256 x tIN
160 x tIN
192 x tIN
224 x tIN
288 x tIN
416 x tIN
32
37
48
69
a)
b)
a)
b)
1
1
0
0
1
1
0
1
0
1
64 x tIN
128 x tIN
256 x tIN
512 x tIN
320 x tIN
384 x tIN
448 x tIN
576 x tIN
832 x tIN
64
74
96
138
a)
c)
a)
c)
n
Figure 6-49
A/D Conversion Timing
Semiconductor Group
6-112
1997-10-01
On-Chip Peripheral Components
C509-L
Sample Time tS :
During this time the internal capacitor array is connected to the selected analog input channel and
is loaded with the analog voltage to be converted. The external analog source needs to be strong
enough to source the current to load the analog input capacitance during the load time. This causes
some restrictions for the impedance of the analog source. The analog voltage is internally fed to a
voltage comparator. With beginning of the sample phase the BSY bit in SFR ADCON0 is set.
Conversion Time tCO :
During the conversion time the analog voltage is converted into a 10-bit digital value using the
successive approximation technique with a binary weighted capacitor network. During a conversion
alternating offset and linearity calibration cycles are executed (see also section 6.6.6). At the end
of the conversion phase the BSY bit is reset and the IADC bit in SFR ADCON0 is set indicating a
A/D converter interrupt condition.
Write Result Time tWR :
At the result phase the conversion result is written into the ADDATH/ADDATL registers.
Figure 6-50 shows how an A/D conversion is embedded into the microcontroller cycle scheme
using the relation 6 x t IN = 1 instruction cycle. It also shows the behaviour of the busy flag (BSY)
and the interrupt flag (IADC) during an A/D conversion.
Depending on the selected prescaler ratios (see figure 6-48), 3 different relationships between
machine cycles and A/D conversion are possible. These 3 relationships are referenced in the
rightmost column of the table in figure 6-49 as a), b), and c).
The single A/D conversion is started when SFR ADDATL is written with dummy data. This write
operation may take one or two machine cycles. In figure 6-50, the instruction MOV ADDATL,#0
starts the A/D conversion (machine cycle X-1 and X). The total A/D conversion (sample, conversion,
and calibration phase) is finished after the end of the n-th machine cycle. In the next machine cycle
n+1 the conversion result is written into the ADDAT registers and can be read in the same cycle by
an instruction (e.g. MOV A,ADDATL). If continuous conversion is selected (bit ADM set), the next
conversion is started with the beginning of the machine cycle which follows the writre result cycle.
The BSY bit is set at the beginning of the first A/D conversion machine cycle and reset at the
beginning of the write result cycle. If continuous conversion is selected, BSY is again set with the
beginning of the machine cycle which follows the write result cycle (n+1).
The interrupt flag IADC is set at the end of the A/D conversion. If the A/D converter interrupt is
enabled and the A/D converter interrupt is priorized to be serviced immediately, the first instruction
of the interrupt service routine will be executed in machine cycle n+4 or n+5. IADC must be reset
by software.
Semiconductor Group
6-113
1997-10-01
On-Chip Peripheral Components
C509-L
Figure 6-50
A/D Conversion Timing in Relation to Processor Cycles
Semiconductor Group
6-114
1997-10-01
On-Chip Peripheral Components
C509-L
Depending on the application, typically there are three software methods to handle the A/D
conversion in the C509-L.
– Software delay
The machine cycles of the A/D conversion are counted and the program executes a software
delay (e.g. NOPs) before reading the A/D conversion result in the write result cycle. This is
the fastest method to get the result of an A/D conversion.
– Polling BSY bit
The BSY bit is polled and the program waits until BSY=0. Attention : a polling JB instruction
which is two machine cycles long, possibly may not recognize the BSY=0 condition during the
write result cycle in the continuous conversion mode.
– A/D conversion interrupt
After the start of an A/D conversion the A/D converter interrupt is enabled. The result of the
A/D conversion is read in the interrupt service routine. If other SAB-C509 interrupts are
enabled, the interrupt latency must be regarded. Therefore, this software method is the
slowest method to get the result of an A/D conversion.
Depending on the oscillator frequency of the C509-L and the selected divider ratios of the A/D
converter prescalers the total time of an A/D conversion is calculated according to table 6-13. The
minimum conversion time is 6 µs.
Table 6-13
A/D Conversion Times
Conversion Clock Sample Clock
Prescaler
Prescaler
ADCL1
ADCL0
ADST1 ADST0
Processor Clock Rate
3.5 MHz
8 MHz
12 MHz
16 MHz
fADC tADCC fADC tADCC fADC tADCC fADC tADCC
[MHz] [µs] [MHz] [µs] [MHz] [µs] [MHz] [µs]
0
0
0
0
1
1
0
1
0
1
0.875 13.7
16
20.6
29.7
2
6
7
9
13
3
4
4.7
6
8.7
4
3
3.5
4.5
6.5
0
1
0
0
1
1
0
1
0
1
0.438 27.4
32
41.1
59.4
1
12
14
18
26
1.5
8
9.3
12
17.3
2
6
7
9
13
1
0
0
0
1
1
0
1
0
1
0.219 54.9 0.5
64
82.3
118.9
24
28
36
52
0.75
16
18.7
24
34.7
1
12
14
18
26
1
1
0
0
1
1
0
1
0
1
0.109 109.7 0.25
128
164.6
237.7
48
56
72
104
0.375 32
37.3
48
69.3
0.5
24
28
36
52
Note : The shaded prescaler/frequency combinations must not be used. Reason : fADC > 2 MHz.
Semiconductor Group
6-115
1997-10-01
On-Chip Peripheral Components
C509-L
6.6.5 Adjustment of the Sample Time
As already discussed, the maximum input clock fADC for the A/D converter is 2 MHz. This must be
taken into account when programming the A/D converter input clock prescalers. Additionally, the
C509-L allows to adapt the sample phase of an A/D conversion to the impedance of an analog input
source. This chapter gives some hints how an optimal adaption of the sample phase is achieved.
At the end of an A/D conversion (single conversion mode) the internal capacitor array is internally
precharged to a voltage level between VAGND and V AREF (approx. 2-3 V). When an A/D
conversion of an analog voltage U0 is started, the voltage level at the analog input pin drops (or
raises) shortly to the precharge voltage level UP and then raises (or drops) back to U0 with a typical
RC load curve (see figure 6-51).
Figure 6-51
Typical Wavefoms at the Analog Inputs During the Sample Phase
The characteristics of the RC load curves as shown in figure 6-51 a) and b) is determined by the
input capacitance CIN of the analog input pin, by the impedance R of the driving analog source, and
by the voltage difference between U0 and UP.
The external analog source needs to be strong enough (low impedance) to source the current for
loading the analog input capacitance. Depending on the accuracy or error requirements of an A/D
conversion, the limits for the input impedance of the analog source can be calculated using the
following formula :
u(t)
R MAX = - t S / (CIN • In (error) )
with error = 1 U0
tS :
sample time
CIN : analog input capacitance (typically 50 pF)
error : allowed deviation of UIN from U0 at the end of the sample time, given in %
Table 6-14 shows the resulting maximum values for R MAX at f OSC = 16 MHz and a maximum error
of 0.1% (1 or 2 LSB error allowed, additional to the specified total unadjusted error).
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
Table 6-14
Limit Values for the impedance of the Analog Source at fOSC = 16 MHz (CIN = 50pF)
Conversion Clock
Prescaler
ADCL1
ADCL0
Sample Clock
Prescaler
ADST1
Sample Time
(16 MHz)
t S [µs]
ADST0
Impedance RMAX [kΩ]
at 16MHz
Error
1 LSB
2 LSB
0
0
0
0
1
1
0
1
0
1
0.5
1
2
4
–
–
–
–
–
–
–
–
0
1
0
0
1
1
0
1
0
1
1
2
4
8
2.9
5.8
11.6
23.1
3.2
6.4
12.9
25.7
1
0
0
0
1
1
0
1
0
1
2
4
8
16
5.8
11.6
23.1
46.3
6.4
12.9
25.7
51.5
1
1
0
0
1
1
0
1
0
1
4
8
16
32
11.6
23.1
46.3
92.6
12.9
25.7
51.5
103
Note : The shaded prescaler combination can only be used up to fOSC = 8 MHz.
Reason : fADC > 2 MHz for fOSC > 8 MHz.
The values in table 6-14 are just calculated values and are no assured limit characteristics.
System environment and application dependencies must be taken into account, too.
Semiconductor Group
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1997-10-01
On-Chip Peripheral Components
C509-L
6.6.6 A/D Converter Calibration
The C509-L A/D converter includes hidden internal calibration mechanisms which assure a save
functionality of the A/D converter according to the DC characteristics. The A/D converter calibration
is implemented in a way that a user program which executes A/D conversions is not affected by its
operation. Further, the user program has no control on the calibration mechanism. The calibration
itself executes two basic functions :
– Offset calibration
– Linearity calibration
: compensation of the offset error of the internal comparator
: correction of the binary weighted capacitor network
The A/D converter calibration operates in two phases : calibration after a reset operation and
calibration at each A/D conversion. The calibration phases are controlled by a state machine in the
A/D converter. This state machine executes the calibration phases and stores the calibration results
dynamically in a small calibration RAM
After a reset operation the A/D calibration is automatically started. This reset calibration phase
which takes 3328 fADC clocks, alternating offset and linearity calibration is executed. Therefore, at
12 MHz oscillator frequency and with the default after reset prescaler value of 8, a reset calibration
time of approx. 2.2 ms is reached. For achieving a proper reset calibration, the fADC prescaler value
must satisfy the condition fADC max ≤ 2 MHz.
After the reset calibration phase the A/D converter is calibrated according to its DC characteristics.
Nevertheless, during the reset calibration phase single or continuous A/D can be executed. In this
case it must be regarded that the reset calibration is interrupted and continued after the end of the
A/D conversion. Therefore, interrupting the reset calibration phase by A/D conversions extends the
total reset calibration time. If the specified total unadjusted error (TUE) has to be valid for an A/D
conversion, it is recommended to start the first A/D conversions after reset when the reset
calibration phase is finished. Depending on the oscillator frequency used, the reset calibration
phase can be possibly shortened by setting ADCL1 and ADCL0 (prescaler value) to its final value
immediately after reset.
After the reset calibration, a second calibration mechanism is initiated. This calibration is coupled
to each A/D conversion. With this second calibration mechanism alternatively offset and linearity
calibration values, stored in the calibration RAM, are always checked when an A/D conversion is
executed and corrected if required.
Semiconductor Group
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1997-10-01
Interrupt System
C509-L
7
Interrupt System
The C509-L provides 19 interrupt sources with four priority levels. 12 interrupts can be generated by
the on-chip peripherals and 7 interrupts may be triggered externally.
The interrupt structure of the C509-L has been mainly adapted from the SAB 80C517A
microcontroller. Thus, each interrupt source has its dedicated interrupt vector and can be enabled/
disabled individually. There are also four priority levels available.
In the C509-L the 19 interrupt sources are combined to six groups of three or four interrupt sources.
Each interrupt group can be programmed to one of the four interrupt priority levels.
7.1
Structure of the Interrupt System
Figure 7-1 to 7-4 give a general overview of the interrupt sources and illustrate the request and
control flags described in the next sections.
Semiconductor Group
7-1
1997-10-01
Interrupt System
C509-L
Figure 7-1
Interrupt Structure, Overview Part 1
Semiconductor Group
7-2
1997-10-01
Interrupt System
C509-L
Figure 7-2 :
Interrupt Structure, Overview Part 2
Semiconductor Group
7-3
1997-10-01
Interrupt System
C509-L
Figure 7-3 :
Interrupt Structure, Overview Part 3
Semiconductor Group
7-4
1997-10-01
Interrupt System
C509-L
Figure 7-4 :
Interrupt Structure, Overview Part 4
Semiconductor Group
7-5
1997-10-01
Interrupt System
C509-L
7.2
Interrupt Registers
7.2.1 Interrupt Enable Registers
Each interrupt vector can be individually enabled or disabled by setting or clearing the
corresponding bit in the interrupt enable registers IEN0, IEN1, IEN2. and IEN3. Register IEN0 also
contains the global disable bit (EAL), which can be cleared to disable all interrupts at once. Some
interrupts sources have further enable bits (e.g. EXEN2). Such interrupt enable bits are controlled
by specific bits in the SFRs of the corresponding peripheral units (described in chapter 6). This
section describes the locations and meanings of these interrupt enable bits in detail.
After reset the enable bits of the interrupt enable registers IEN0 to IEN3 are set to 0. That means
that the corresponding interrupts are disabled.
The SFR IEN0 includes the enable bits for the external interrupts 0 and 1, the timer 0,1, and 2
interrupts, the serial interface 0 interrupt, and the general interrupt enable control bit EAL.
Special Function Register IEN0 (Address A8H)
Bit No.
MSB
AFH
A8H
EAL
AEH
WDT
ADH
ET2
ACH
ES0
Reset Value : 00H
ABH
ET1
AAH
A9H
LSB
A8H
EX1
ET0
EX0
IEN0
The shaded bit is not used for interrupt control
Bit
Function
EAL
Enable/disable all interrupts.
If EA=0, no interrupt will be acknowledged.
If EA=1, each interrupt source is individually enabled or disabled by setting or
clearing its enable bit.
ET2
Timer 2 interrupt enable.
If ET2 = 0, the timer 2 interrupt is disabled.
ES0
Serial channel 0 interrupt enable
If ES0 = 0, the serial channel interrupt 0 is disabled.
ET1
Timer 1 overflow interrupt enable.
If ET1 = 0, the timer 1 interrupt is disabled.
EX1
External interrupt 1 enable.
If EX1 = 0, the external interrupt 1 is disabled.
ET0
Timer 0 overflow interrupt enable.
If ET0 = 0, the timer 0 interrupt is disabled.
EX0
External interrupt 0 enable.
If EX0 = 0, the external interrupt 0 is disabled.
Semiconductor Group
7-6
1997-10-01
Interrupt System
C509-L
The SFR IEN1 includes the enable bits for the external interrupts 2 to 6, for the AD converter
interrupt, and for the timer 2 external reload interrupt.
Special Function Register IEN1 (Address B8H)
Bit No.
B8H
MSB
BFH
BEH
EXEN2 SWDT
BDH
EX6
BCH
EX5
Reset Value : 00H
BBH
EX4
BAH
B9H
LSB
B8H
EX3
EX2
EADC
IEN1
The shaded bit is not used for interrupt control
Bit
Function
EXEN2
Timer 2 external reload interrupt enable
If EXEN2 = 0, the timer 2 external reload interrupt is disabled.
The external reload function is not affected by EXEN2.
EX6
External interrupt 6 / capture/compare interrupt 3 enable
If EX6 = 0, external interrupt 6 is disabled.
EX5
External interrupt 5 / capture/compare interrupt 2 enable
If EX5 = 0, external interrupt 5 is disabled.
EX4
External interrupt 4 / capture/compare interrupt 1 enable
If EX4 = 0, external interrupt 4 is disabled.
EX3
External interrupt 3 / capture/compare interrupt 0 enable
If EX3 = 0, external interrupt 3 is disabled.
EX2
External interrupt 2 / capture/compare interrupt 4 enable
If EX2 = 0, external interrupt 2 is disabled.
EADC
Timer 2 external reload interrupt enable
If EADC = 0, the A/D converter interrupt is disabled
Semiconductor Group
7-7
1997-10-01
Interrupt System
C509-L
The SFR IEN2 includes the enable bits for the compare match with compare register interrupts, the
compare timer overflow interrupt, and the serial interface 1 interrupt.
Special Function Register IEN2 (Address 9AH)
Bit No.
9AH
Reset Value : XX0000X0B
MSB
7
6
5
4
3
2
1
LSB
0
–
–
ECR
ECS
ECT
ECMP
–
ES1
Bit
Function
–
Reserved bits for future use.
ECR
COMCLR register compare match interrupt enable
If ECR = 0, the COMCLR compare match interrupt is disabled.
ECS
COMSET register compare match interrupt enable
If ECS = 0, the COMSET compare match interrupt is disabled.
ECT
Enable compare timer interrupt enable
If ECT = 0, the compare timer overflow interrupt is disabled.
ECMP
CM0-7 register compare match interrupt enable
If ECMP = 0, the CM0-7 compare match interrupt is disabled.
ES1
Serial Interface 1 interrupt enable
if ES1 = 0, the serial interrupt 1 is disabled.
Semiconductor Group
7-8
IEN2
1997-10-01
Interrupt System
C509-L
The SFR IEN3 includes the enable bits for the compare timer 1 overflow interrupt and the general
capture/compare interrupt of the compare timer 1.
compare match with compare register interrupts, the compare, and the serial interface 1 interrupt.
Special Function Register IEN3 (Address BEH)
Bit No.
BEH
Reset Value : XXXX00XXB
MSB
7
6
5
4
3
2
1
LSB
0
–
–
–
–
ECT1
ECC1
–
–
IEN3
Bit
Function
–
Reserved bits for future use.
ECT1
Compare timer 1 overflow interrupt enable
If ECT1 = 0, the interrupt at compare timer 1 overflow is disabled.
ECC1
Compare timer 1, general capture/compare interrupt enable
This bit enables the interrupt on an capture/compare event in the capture/compare
registers CC10 - CC17. Additionally, the SFR EICC1 must be programmed to
enable the interrupt request. With ECC1=0, the general capture/compare timer 1
interrupt is disabled.
The SFR EICC1 includes the enable bits for the specific capture/compare interrupt of the compare
timer 1.
Special Function Register EICC1 (Mapped Address BFH)
Bit No.
BFH
MSB
7
6
5
4
3
2
Reset Value : FFH
1
LSB
0
EICC17 EICC16 EICC15 EICC14 EICC13 EICC12 EICC11 EICC10
EICC1
Bit
Function
EICC17 EICC10
Compare timer 1, specific capture/compare interrupt enable
This bit enables the interrupt on an capture/compare event in the capture/compare
registers CC10 - CC17. When EICC1x=0, the interrupt request flag ICC1x has no
effect on the interrupt unit. EICC17 refers to CC17 etc.
EICC1 is mapped to the SFR IRCON2. It is selected by a double instruction sequence with PDIR
set.
Semiconductor Group
7-9
1997-10-01
Interrupt System
C509-L
7.2.2 Interrupt Priority Registers
The 19 interrupt sources of the C509-L are combined to six interrupt groups (see table 7-1). Each
of the six interrupt groups can be programmed to one of four priority levels by setting or clearing a
bit in the IP0 and IP1 priority registers. Further details about the interrupt priority structure are given
in chapter 7.3.
Special Function Register IP0 (Address A9H)
Special Function Register IP1 (Address B9H)
Bit No.
A9H
B9H
MSB
7
5
4
3
2
1
LSB
0
IP0.5
IP0.4
IP0.3
IP0.2
IP0.1
IP0.0
6
OWDS WDTS
Reset Value : 00H
Reset Value : 0X000000B
7
6
5
4
3
2
1
0
PDIR
–
IP1.5
IP1.4
IP1.3
IP1.2
IP1.1
IP1.0
IP0
IP1
The shaded bits are not used for interrupt purposes.
Bit
Function
IP1.x
IP1.x
Interrupt Priority level bits (x=0-5)
Semiconductor Group
IP1.x
IP0.x
Function
0
0
Interrupt group x is set to priority level 0 (lowest)
0
1
Interrupt group x is set to priority level 1
1
0
Interrupt group x is set to priority level 2
1
1
Interrupt group x is set to priority level 3 (highest)
7-10
1997-10-01
Interrupt System
C509-L
7.2.3 Interrupt Request Flags
The request flags for the different interrupt sources are located in several special function registers.
This section describes the locations and meanings of these interrupt request flags in detail.
The external interrupts 0 and 1 (P3.2/INT0 and P3.3/INT1) can each be either level-activated or
negative transition-activated, depending on bits IT0 and IT1 in SFR TCON. The flags that actually
generate these interrupts are bits IE0 and lE1 in SFR TCON. When an external interrupt is
generated, the flag that generated this interrupt is cleared by the hardware when the service routine
is vectored to, but only if the interrupt was transition-activated. lf the interrupt was level-activated,
then the requesting external source directly controls the request flag, rather than the on-chip
hardware.
The timer 0 and timer 1 interrupts are generated by TF0 and TF1 in register TCON, which are set
by a rollover in their respective timer/counter registers (exception is timer 0 in mode 3). When a
timer interrupt is generated, the flag that generated it is cleared by the on-chip hardware when the
service routine is vectored to.
Special Function Register TCON (Address 88H)
Bit No.
88H
MSB
8FH
TF1
8EH
TR1
8DH
TF0
8CH
TR0
Reset Value : 00H
8BH
IE1
8AH
89H
LSB
88H
IT1
IE0
IT0
TCON
The shaded bits are not used for interrupt purposes.
Bit
Function
TF1
Timer 1 overflow flag
Set by hardware on timer/counter 1 overflow. Cleared by hardware when
processor vectors to interrupt routine.
TF0
Timer 0 overflow flag
Set by hardware on timer/counter 0 overflow. Cleared by hardware
when processor vectors to interrupt routine.
IE1
External interrupt 1 request flag
Set by hardware. Cleared by hardware when processor vectors to interrupt routine
(if IT1 = 1) or by hardware (if IT1 = 0).
IT1
External interrupt 1 level/edge trigger control flag
If IT1 = 0, level triggered external interrupt 1 is selected.
If IT1 = 1, negative edge triggered external interrupt 1 is selected.
IE0
External interrupt 0 request flag
Set by hardware. Cleared by hardware when processor vectors to interrupt routine
(if IT0 = 1) or by hardware (if IT0 = 0).
IT0
External interrupt 0 level/edge trigger control flag
If IT0 = 0, level triggered external interrupt 0 is selected.
If IT0 = 1, negative edge triggered external interrupt 0 is selected.
Semiconductor Group
7-11
1997-10-01
Interrupt System
C509-L
The interrupt of the serial interface 0 is generated by the request flags RI0 and TI0 in SFR
S0CON. The two request flags of the serial interface are logically OR-ed together. Neither of these
flags is cleared by hardware when the service routine is vectored to. In fact, the service routine of
each interface will normally have to determine whether it was the receive interrupt flag or the
transmission interrupt flag that generated the interrupt, and the bit will have to be cleared by
software.
The interrupt of the serial interface 1 is generated by the request flags RI1 and TI1 in SFR
S1CON. The two request flags of the serial interface are logically OR-ed together. Neither of these
flags is cleared by hardware when the service routine is vectored to. In fact, the service routine of
each interface will normally have to determine whether it was the receive interrupt flag or the
transmission interrupt flag that generated the interrupt, and the bit will have to be cleared by
software.
Special Function Register S0CON (Address 98H)
Special Function Register S1CON (Address 9BH)
Reset Value : 00H
Reset Value : 01000000B
Bit No.
MSB
9FH
9EH
9DH
9CH
9BH
9AH
99H
LSB
98H
98H
SM0
SM10
SM20
REN0
TB80
RB80
TI0
RI0
7
6
5
4
3
2
1
0
SM
S1P
SM21
REN1
TB81
RB81
TI1
RI1
9BH
S0CON
S1CON
The shaded bits are not used for interrupt purposes.
Bit
Function
TI0
Serial interface 0 transmitter interrupt flag
Set by hardware at the end of a serial data transmission. Must be cleared by
software.
RI0
Serial interface 0 receiver interrupt flag
Set by hardware if a serial data byte has been received. Must be cleared by
software.
TI1
Serial interface 1 transmitter interrupt flag
Set by hardware at the end of a serial data transmission. Must be cleared by
software.
RI1
Serial interface 1 receiver interrupt flag
Set by hardware if a serial data byte has been received. Must be cleared by
software.
Semiconductor Group
7-12
1997-10-01
Interrupt System
C509-L
The external interrupt 2 (INT2/CC4) can be either positive or negative transition-activated
depending on bit I2FR in register T2CON. The flag that actually generates this interrupt is bit IEX2
in register IRCON. In addition, this flag will be set if a compare event occurs at the corresponding
output pin P1.4/INT2/CC4, regardless of the compare mode established and the transition at the
respective pin. lf an interrupt 2 is generated, flag IEX2 is cleared by hardware when the service
routine is vectored to.
Like the external interrupt 2, the external interrupt 3 can be either positive or negative transitionactivated, depending on bit I3FR in register T2CON. The flag that actually generates this interrupt
is bit IEX3 in register IRCON0. In addition, this flag will be set if a compare event occurs at pin
P1.0/INT3/CC0, regardless of the compare mode established and the transition at the respective
pin. The flag IEX3 is cleared by hardware when the service routine is vectored to.
The external interrupts 4 (INT4), 5 (INT5), 6 (INT6) are positive transition-activated. The flags that
actually generate these interrupts are bits IEX4, IEX5, and IEX6 in register IRCON0. In addition,
these flags will be set if a compare event occurs at the corresponding output pin P1.1/INT4/CC1,
P1.2/INT5/CC2, and P1.3/INT6/CC3, regardless of the compare mode established and the
transition at the respective pin. When an interrupt is generated, the flag that generated it is cleared
by the on-chip hardware when the service routine is vectored to.
The timer 2 interrupt is generated by the logical OR of bit TF2 in SFR T2CON and bit EXF2 in SFR
IRCON0. Neither of these flags is cleared by hardware when the service routine is vectored to. In
fact, the service routine may have to determine whether it was TF2 or EXF2 that generated the
interrupt, and the bit will have to be cleared by software.
The A/D converter interrupt is generated by IADC in register IRCON0. lt is set some cycles before
the result is available. That is, if an interrupt is generated, in any case the converted result in ADDAT
is valid on the first instruction of the interrupt service routine (with respect to the minimal interrupt
response time). lf continuous conversions are established, IADC is set once during each
conversion. lf an A/D converter interrupt is generated, flag IADC must be cleared by software.
Special Function Register T2CON (Address C8H)
Bit No.
MSB
CFH
C8H
T2PS
CEH
I3FR
CDH
I2FR
CCH
T2R1
Reset Value : 00H
CBH
T2R0
CAH
C9H
T2CM
T2I1
LSB
C8H
T1I0
T2CON
The shaded bits are not used for interrupt purposes.
Bit
Function
I3FR
External interrupt 3 rising/falling edge control flag
If I3FR = 0, the external interrupt 3 is activated by a negative transition at INT3.
If I3FR = 1, the external interrupt 3 is activated by a positive transition at INT3.
I2FR
External interrupt 2 rising/falling edge control flag
If I3FR = 0, the external interrupt 3 is activated by a negative transition at INT2.
If I3FR = 1, the external interrupt 3 is activated by a positive transition at INT2.
Semiconductor Group
7-13
1997-10-01
Interrupt System
C509-L
Special Function Register IRCON0 (Address C0H)
Bit No.
MSB
C7H
C0H
EXF2
C6H
TF2
C5H
IEX6
C4H
IEX5
C3H
IEX4
Reset Value : 00H
C2H
C1H
LSB
C0H
IEX3
IEX2
IADC
IRCON0
Bit
Function
EXF2
Timer 2 external reload flag
Set when a reload is caused by a negative transition on pin T2EX while EXEN2 = 1.
If ET2 in IEN0 is set (timer 2 interrupt enabled), EXF2 = 1 will cause an interrupt.
Can be used as an additional external interrupt when the reload function is not
used. EXF2 must be cleared by software.
TF2
Timer 2 overflow flag
Set by a timer 2 overflow and must be cleared by software. If the timer 2 interrupt
is enabled, TF2 = 1 will cause an interrupt.
IEX6
External interrupt 6 edge flag
Set by hardware when external interrupt edge was detected or when a compare
event occurred at pin 1.3/INT6/CC3. Cleared by hardware when processor vectors
to interrupt routine.
IEX5
External interrupt 5 edge flag
Set by hardware when external interrupt edge was detected or when a compare
event occurred at pin 1.2/INT5/CC2. Cleared by hardware when processor vectors
to interrupt routine.
IEX4
External interrupt 4 edge flag
Set by hardware when external interrupt edge was detected or when a compare
event occurred at pin 1.1/INT4/CC1. Cleared by hardware when processor vectors
to interrupt routine.
IEX3
External interrupt 3 edge flag
Set by hardware when external interrupt edge was detected or when a compare
event occurred at pin 1.0/INT3/CC0. Cleared by hardware when processor vectors
to interrupt routine.
IEX2
External interrupt 2 edge flag
Set by hardware when external interrupt edge was detected or when a compare
event occurred at pin 1.4/INT2/CC4. Cleared by hardware when processor vectors
to interrupt routine.
IADC
A/D converter interrupt request flag
Set by hardware at the end of a conversion. Must be cleared by software.
Semiconductor Group
7-14
1997-10-01
Interrupt System
C509-L
The compare timer match interrupt occurs on a compare match of the CM0 to CM7 registers with
the compare timer when compare mode 1 is selected for the corresponding channel. There are 8
compare match interrupt flags available in SFR IRCON1 which are or-ed together for a single
interrupt request. Thus, a compare match interrupt service routine has to check which compare
match has requested the compare match interrupt. The ICMPx flags must be cleared by software.
Only if timer 2 is assigned to the CMx registers (compare mode 0), an ICMPx request flag is set by
every match in the compare channel. When the compare timer is assigned to the CMx registers
(compare mode 1), an ICMPx request flag will not be set by a compare match event.
Special Function Register IRCON1 (Address D1H)
Bit No.
D1H
MSB
7
6
5
4
3
Reset Value : 00H
2
1
LSB
0
ICMP7 ICMP6 ICMP5 ICMP4 ICMP3 ICMP2 ICMP1 ICMP0
IRCON1
Bit
Function
ICMP7 - 0
Compare timer match with register CM7 - CM0 interrupt flags
ICMPx is set by hardware when a compare match of the compare timer with the
compare register CMx occurs but only if the compare function for CMx has been
enabled.
ICMPx must be cleared by software (CMSEL.x = 0 and CMEN.x = 1).
The compare timer 1 match interrupt occurs on a compare match of the CC10 to CC17 registers
with the compare timer 1 or (if selected) at a capture event at the pins CC10 to CC17. There are 8
compare match/capture interrupt flags available in SFR IRCON2 which are or-ed together for a
single interrupt request. Thus, a compare match/capture interrupt service routine has to check
which compare match/capture event has occurred. The ICC1x flags must be cleared by software.
Special Function Register IRCON2 (Address BFH)
Bit No.
BFH
MSB
7
6
5
4
3
Reset Value : 00H
2
1
LSB
0
ICC17 ICC16 ICC15 ICC14 ICC13 ICC12 ICC11 ICC10
IRCON2
Bit
Function
ICC17 - 10
Compare timer 1 match with register CC17 - CC10 interrupt flags
ICC1x is set by hardware when a compare match of the compare timer 1 with the
compare register CC1x occurs but only if the compare function for CC1x has been
enabled.
ICC1x must be cleared by software.
Semiconductor Group
7-15
1997-10-01
Interrupt System
C509-L
The compare timer interrupt is generated by bit CTF in register CTCON, which is set by a rollover
in the compare timer. lf a compare timer interrupt is generated, flag CTF can be cleared by software.
The compare timer 1 interrupt is generated by bit CT1F in register CT1CON, which is set by a
rollover in the compare timer. lf a compare timer interrupt is generated, flag CT1F can be cleared
by software.
The timer 2 compare match set and compare match clear interrupt is generated by bits ICS
and ICR in register CTCON. These flags are set by a match in registers COMSET and COMCLR,
when enabled. As long as the match condition is valid the request flags can't be reset (neither by
hardware nor software).
Special Function Register CTCON (Address. E1H)
Special Function Register CT1CON (Address BCH)
Bit No.
E1H
BCH
Reset Value : 01000000B
Reset Value : X1XX0000B
6
5
4
3
2
1
LSB
0
T2PS1
CTP
ICR
ICS
CTF
CLK2
CLK1
CLK0
7
6
5
4
3
2
1
0
–
CT1P
–
–
MSB
7
CT1F CLK12 CLK11 CLK10
CTCON
CT1CON
The shaded bits are not used for interrupt purposes.
Bit
Function
ICR
Interrupt request flag for compare register COMCLR
ICR is set when a compare match occured. ICR is cleared ba hardware when the
processor vectors to interrupt routine.
ICS
Interrupt request flag for compare register COMSET
ICS is set when a compare match occured. ICS is cleared by hardware when the
processor vectors to interrupt routine.
CTF
Compare timer overflow flag
CTF is set when the compare timer 1 count rolls over from all ones to the reload
value. When CTF is set, a compare timer interrupt can be generated (if enabled).
CTF is cleared by hardware when the compare timer value is no more equal to the
reload value.
CT1F
Compare timer 1 overflow flag
CT1F is set when the compare timer 1 count rolls over from all ones to the reload
value. When CT1F is set, a compare timer 1 interrupt can be generated (if enabled).
CT1F is cleared by hardware when the compare timer 1 value is no more equal its
reload value.
Semiconductor Group
7-16
1997-10-01
Interrupt System
C509-L
7.3
Interrupt Priority Level Structure
The 19 interrupt sources of the C509-L are combined in six groups. Table 7-1 lists the structure of
these interrupt groups.
Table 7-1
Interrupt Source Structure
Interrupt
Groups
Associated Interrupts
1
External interrupt 0
Serial channel 1
interrupt
A/D converter
interrupt
--
2
Timer 0 overflow
--
External interrupt 2
--
3
External interrupt 1
Match in CM0-CM7 External interrupt 3
Match in CC10CC17 or capture
event at port 9
4
Timer 1 overflow
Compare timer
overflow
External interrupt 4
Compare timer 1
overflow
5
Serial channel 0
interrupt
Match in COMSET
External interrupt 5
--
6
Timer 2 overflow or
external reload
interrupt
Match in COMCLR
External interrupt 6
--
Each group of interrupt sources can be programmed individually to one of four priority levels by
setting or clearing one bit in the special function register IP0 and one in IP1. A low-priority interrupt
can itself be interrupted by a high-priority interrupt, but not by another interrupt of the same or a
lower priority. An interrupt of the highest priority level cannot be interrupted by another interrupt
source.
lf two or more requests of different priority levels are received simultaneously, the request of the
highest priority is serviced first. lf requests of the same priority level are received simultaneously,
an internal polling sequence determines which request is to be serviced first. Thus, within each
priority level there is a second priority structure determined by the polling sequence (table 7-2).
Semiconductor Group
7-17
1997-10-01
Interrupt System
C509-L
Table 7-2
Interrupts - Priority-within-Level
Interrupt Priority Bits
Group
of Interrupt
Group
Interrupt Source Priority
1
IP1.0 / IP0.0
IE0
RI1 + TI1
IADC
–
2
IP1.1 / IP0.1
TF0
–
IEX2
–
3
IP1.2 / IP0.0
IE0
ICMP0-7
IEX3
ICC10-17
4
IP1.3 / IP0.3
TF1
CTF
IEX4
CTF1
5
IP1.4 / IP0.4
RI0 + TI0
ICS
IEX5
–
6
IP1.5 / IP0.5
TF2 + EXF2
ICR
IEX6
–
High Priority
Low Priority
Interrupt
Group
Priority
High
Low
Within one pair or triplet the leftmost interrupt is serviced first, then the second and third, when
available. The interrupt groups are serviced from top to bottom of the table. A low-priority interrupt
can itself be interrupted by a higher-priority interrupt, but not by another interrupt of the same or a
lower priority. An interrupt of the highest priority level cannot be interrupted by another interrupt
source.
If two or more requests of different priority levels are received simultaneously, the request of the
highest priority is serviced first. If requests of the same priority level are received simultaneously, an
internal polling sequence determines which request is to be serviced first. Thus, within each priority
level there is a second priority structure which is illustrated in table 7-2.
The “priority-within-level” structure is only used to resolve simultaneous requests of the same
priority level.
Semiconductor Group
7-18
1997-10-01
Interrupt System
C509-L
7.4
How Interrupts are Handled
The interrupt flags are sampled at S5P2 in each machine cycle. The sampled flags are polled during
the following machine cycle. If one of the flags was in a set condition at S5P2 of the preceeding
cycle, the polling cycle will find it and the interrupt system will generate a LCALL to the appropriate
service routine, provided this hardware-generated LCALL is not blocked by any of the following
conditions:
1. An interrupt of equal or higher priority is already in progress.
2. The current (polling) cycle is not in the final cycle of the instruction in progress.
3. The instruction in progress is RETI or any write access to registers IEN0, IEN1, IEN2, IEN3,
EICC1, IP1 or IP0.
Any of these three conditions will block the generation of the LCALL to the interrupt service routine.
Condition 2 ensures that the instruction in progress is completed before vectoring to any service
routine. Condition 3 ensures that if the instruction in progress is RETI or any write access to
registers IEN0, IEN1, IEN2, IEN3, EICC1, IP1 or IP0, then at least one more instruction will be
executed before any interrupt is vectored to; this delay guarantees that changes of the interrupt
status can be observed by the CPU.
The polling cycle is repeated with each machine cycle and the values polled are the values that
were present at S5P2 of the previous machine cycle. Note that if any interrupt flag is active but not
being responded to for one of the conditions already mentioned, or if the flag is no longer active
when the blocking condition is removed, the denied interrupt will not be serviced. In other words, the
fact that the interrupt flag was once active but not serviced is not remembered. Every polling cycle
interrogates only the pending interrupt requests.
The polling cycle/LCALL sequence is illustrated in figure 7-5.
C1
C2
C3
C4
C5
S5P2
Interrupt
is latched
Interrupts
are polled
Long Call to Interrupt
Vector Address
Interrupt
Routine
MCT01859
Figure 7-5
Interrupt Response Timing Diagram
Semiconductor Group
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1997-10-01
Interrupt System
C509-L
Note that if an interrupt of a higher priority level goes active prior to S5P2 in the machine cycle
labeled C3 in figure 7-5 then, in accordance with the above rules, it will be vectored to during C5
and C6 without any instruction for the lower priority routine to be executed.
Thus, the processor acknowledges an interrupt request by executing a hardware-generated LCALL
to the appropriate servicing routine. In some cases it also clears the flag that generated the
interrupt, while in other cases it does not. Then this has to be done by the user's software. The
hardware clears the external interrupt flags IE0 and IE1 only if they were transition-activated. The
hardware-generated LCALL pushes the contents of the program counter onto the stack (but it does
not save the PSW) and reloads the program counter with an address that depends on the source of
the interrupt being vectored to, as shown in table 7-3.
Table 7-3
Interrupt Source and Vectors
Interrupt Source
Interrupt Vector Address
Interrupt Request Flags
External Interrupt 0
0003H
IE0
Timer 0 Overflow
000BH
0013H
TF0
001BH
0023H
TF1
002BH
0043H
TF2 / EXF2
004BH
0053H
IEX2
005BH
0063H
IEX4
006BH
0083H
IEX6
Compare Match Interrupt of
Compare Registers CM0-CM7
assigned to Timer 2
0093H
ICMP0 - ICMP7
Compare Timer Overflow
009BH
CTF
Compare Match Interrupt of
Compare Register COMSET
00A3H
ICS
Compare Match Interrupt of
Compare Register COMCLR
00ABH
ICR
External Interrupt 1
Timer 1 Overflow
Serial Channel 0
Timer 2 Overflow / Ext. Reload
A/D Converter
External Interrupt 2
External Interrupt 3
External Interrupt 4
External Interrupt 5
External Interrupt 6
Serial Channel 1
IE1
RI0 / TI0
IADC
IEX3
IEX5
RI1 / TI1
Compare / Capture Event interrupt 00D3H
ICC10 - ICC17
Compare Timer 1 Overflow
CT1F
Semiconductor Group
00DBH
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1997-10-01
Interrupt System
C509-L
Execution proceeds from that location until the RETI instruction is encountered. The RETI
instruction informs the processor that the interrupt routine is no longer in progress, then pops the
two top bytes from the stack and reloads the program counter. Execution of the interrupted program
continues from the point where it was stopped. Note that the RETI instruction is very important
because it informs the processor that the program left the current interrupt priority level. A simple
RET instruction would also have returned execution to the interrupted program, but it would have
left the interrupt control system thinking an interrupt was still in progress. In this case no interrupt of
the same or lower priority level would be acknowledged.
7.5
External Interrupts
The external interrupts 0 and 1 can be programmed to be level-activated or negative-transition
activated by setting or clearing bit IT0 or IT1, respectively, in register TCON. lf ITx = 0 (x = 0 or 1),
external interrupt x is triggered by a detected low level at the INTx pin. lf ITx = 1, external interrupt
x is negative edge-triggered. In this mode, if successive samples of the INTx pin show a high in one
cycle and a low in the next cycle, interrupt request flag lEx in TCON is set. Flag bit lEx then requests
the interrupt.
lf the external interrupt 0 or 1 is level-activated, the external source has to hold the request active
until the requested interrupt is actually generated. Then it has to deactivate the request before the
interrupt service routine is completed, or else another interrupt will be generated.
The external interrupts 2 and 3 can be programmed to be negative or positive transition-activated
by setting or clearing bit I2FR or I3FR in register T2CON. lf IxFR = 0 (x = 2 or 3), external interrupt
x is negative transition-activated. lf IxFR = 1, external interrupt is triggered by a positive transition.
The external interrupts 4, 5, and 6 are activated by a positive transition. The external timer 2 reload
trigger interrupt request flag EXF2 will be activated by a negative transition at pin P1.5/T2EX but
only if bit EXEN2 is set.
Since the external interrupt pins (INT2 to INT6) are sampled once in each machine cycle, an input
high or low should be held for at least 12 oscillator periods to ensure sampling. lf the external
interrupt is transition-activated, the external source has to hold the request pin low (high for INT2
and INT3, if it is programmed to be negative transition-active) for at least one cycle, and then hold
it high (low) for at least one cycle to ensure that the transition is recognized so that the
corresponding interrupt request flag will be set (see figure 7-6). The external interrupt request flags
will automatically be cleared by the CPU when the service routine is called.
Semiconductor Group
7-21
1997-10-01
Interrupt System
C509-L
Figure 7-6
External Interrupt Detection
7.6
Interrupt Response Time
If an external interrupt is recognized, its corresponding request flag is set at S5P2 in every machine
cycle. The value is not polled by the circuitry until the next machine cycle. If the request is active and
conditions are right for it to be acknowledged, a hardware subroutine call to the requested service
routine will be next instruction to be executed. The call itself takes two cycles. Thus a minimum of
three complete machine cycles will elapse between activation and external interrupt request and the
beginning of execution of the first instruction of the service routine.
A longer response time would be obtained if the request was blocked by one of the three previously
listed conditions. If an interrupt of equal or higher priority is already in progress, the additional wait
time obviously depends on the nature of the other interrupt's service routine. If the instruction in
progress is not in its final cycle, the additional wait time cannot be more than 3 cycles since the
longest instructions (MUL and DIV) are only 4 cycles long; and, if the instruction in progress is RETI
or a write access to registers IE or IP the additional wait time cannot be more than 5 cycles (a
maximum of one more cycle to complete the instruction in progress, plus 4 cycles to complete the
next instruction, if the instruction is MUL or DIV).
Thus a single interrupt system, the response time is always more than 3 cycles and less than
9 cycles.
Semiconductor Group
7-22
1997-10-01
Fail Save Mechanisms
C509-L
8
Fail Save Mechanisms
The C509-L offers two on-chip peripherals which monitor the program flow and ensure an automatic
“fail-safe” reaction for cases where the controller’s hardware fails or the software hangs up:
– A programmable watchdog timer (WDT) with variable time-out period from 189 microseconds
up to approx. 0.79 seconds at 16 MHz.
– An oscillator watchdog (OWD) which monitors the on-chip oscillator and forces the
microcontroller into the reset state if the on-chip oscillator fails.
8.1
Programmable Watchdog Timer
To protect the system against software upset, the user’s program has to clear this watchdog within
a previously programmed time period. lf the software fails to do this periodical refresh of the
watchdog timer, an internal hardware reset will be initiated. The software can be designed so that
the watchdog times out if the program does not work properly. lt also times out if a software error is
based on hardware-related problems.
The watchdog timer in the C509-L is a 15-bit timer, which is incremented by a count rate of fOSC/12
up to fOSC/384. For programming of the watchdog timer overflow rate, the upper 7 bit of the watchdog
timer can be written. Figure 8-1 shows the block diagram of the watchdog timer unit.
Figure 8-1
Block Diagram of the Programmable Watchdog Timer
Semiconductor Group
8-1
1997-10-01
Fail Save Mechanisms
C509-L
8.1.1 Input Clock Selection
The input clock rate of the watchdog timer is derived from the system clock of the C509-L. There are
two prescalers which define the input clock rate. These prescalers are controlled by two bits in the
SFRs PRSC and WDTREL. Table 8-1 shows the resulting timeout periods at fOSC = 16 MHz.
Special Function Register PRSC (Address B4H)
Special Function Register WDTREL (Address 86H)
Bit No.
B4H
86H
Reset Value : 11010101B
Reset Value : 00H
MSB
7
6
5
4
3
2
1
LSB
0
WDTP
S0P
T2P1
T2P0
T1P1
T1P2
T0P1
T0P0
7
6
5
4
3
2
1
0
Watchdog timer reload value
WPSEL
PRSC
WDTREL
The shaded bits are not used for the watchdog timer.
Bit
Function
WDTP
WPSEL
Prescaler select bits for the watchdog input clock
The two control bits WDTP and WPSEL define the input clock frequency fIN of
the watchdog timer.
WDTREL.6-0
WDTP
WPSEL
Input clock
0
0
fIN = fOSC/12
0
1
fIN = fOSC/192
1
0
fIN = fOSC/24 (reset value)
1
1
fIN = fOSC/384
Watchdog timer reload value
Seven bit reload value for the high-byte of the watchdog timer. This value is
loaded to the WDT when a refresh is triggered by a consecutive setting of bits
WDT and SWDT.
Table 8-1
Watchdog Timer Timeout Periods at fOSC = 16 MHz
WDTREL
Time-Out Periods
Comments
fOSC/12
fOSC/24
fOSC/192
fOSC/384
00H
24.6 ms
49.1 ms
393 ms
786 ms
Maximum time period (default after reset)
(128 WDTL overflows)
7EH
7FH
381 µs
762 µs
6.10 ms
12.2 ms
Two WDTL overflows
189 µs
378 µs
3.02 ms
6.05 ms
Min. time period (One WDTL overflow)
Semiconductor Group
8-2
1997-10-01
Fail Save Mechanisms
C509-L
8.1.2 Watchdog Timer Control Flags
The watchdog timer is controlled by two control flags (located in SFR IEN0 and IEN1) and one
status flags (located in SFR IP0).
Special Function Register IEN0 (Address A8H)
Special Function Register IEN1 (Address B8H)
Special Function Register IP0 (Address A9H)
Bit No.
A8H
B8H
MSB
AFH
AEH
ADH
ACH
ABH
AAH
A9H
LSB
A8H
EAL
WDT
ET2
ES0
ET1
EX1
ET0
EX0
BFH
BEH
BDH
BCH
BBH
BA2H
B91H
B8H
EX6
EX5
EX4
EX3
EX2
5
4
3
2
1
EXEN2 SWDT
7
A9H
Reset Value : 00H
Reset Value : 00H
Reset Value : 00H
6
OWDS WDTS
IP0.5
IP0.4
IP0.3
IP0.2
IP0.1
EADC
IEN0
IEN1
0
IP0.0
IP0
The shaded bits are not used in controlling the watchdog timer.
Bit
Function
WDT
Watchdog timer refresh flag
Set to initiate a refresh of the watchdog timer. Must be set directly before
SWDT is set to prevent an unintentional refresh of the watchdog timer.
SWDT
Watchdog timer start flag
Set to activate the watchdog timer. When directly set after setting WDT,
a watchdog timer refresh is performed.
WDTS
Watchdog timer status flag
Set by hardware when a watchdog timer reset occurred.
Can be cleared or set by software
Semiconductor Group
8-3
1997-10-01
Fail Save Mechanisms
C509-L
8.1.3
Starting the Watchdog Timer
Immediately after start (see next section for the start procedure), the watchdog timer is initialized to
the reload value programmed to WDTREL.0 - WDTREL.6. After an external hardware or HWPD
reset, an oscillator power on reset, or a watchdog timer reset, register WDTREL is cleared to 00H.
WDTREL can be loaded by software at any time.
There are two ways to start the watchdog timer depending on the level applied to pin PE/SWD. This
pin serves two functions, because it is also used for blocking the power saving modes (see also
chapter 9).
8.1.3.1 The First Possibility of Starting the Watchdog Timer
The automatic start of the watchdog timer directly after an external HW reset is a hardware start
initialized by strapping pin PE/SWD to VCC. In this case the power-saving modes (power-down
mode, idle mode and slow-down mode) are also disabled and cannot be started by software.
The self-start of the watchdog timer by a pin option has been implemented to provide high system
security in electrically very noisy environments.
Note: The automatic start of the watchdog timer is only performed if PE/SWD (power-save enable/
start watchdog timer) is held at high level while reset is active. A positive transition at this pin
during normal program execution will not start the watchdog timer.
Furthermore, when using the hardware start, the watchdog timer starts running with its
default time- out period. The value in the reload register WDTREL, however, can be
overwritten at any time to set any time-out period desired.
8.1.3.2 The Second Possibility of Starting the Watchdog Timer
The watchdog timer can also be started by software. Setting of bit SWDT in special function register
IEN1 starts the watchdog timer. Using the software start, the timeout period can be programmed
before the watchdog timer starts running.
Note that once the watchdog timer has been started it cannot be stopped by anything but an
external hardware reset through pin RESET with a low level applied to pin PE/SWD.
Semiconductor Group
8-4
1997-10-01
Fail Save Mechanisms
C509-L
8.1.4 Refreshing the Watchdog Timer
At the same time the watchdog timer is started, the 7-bit register WDTH is preset by the contents of
WDTREL.0 to WDTREL.6. Once started the watchdog cannot be stopped by software but can only
be refreshed to the reload value by first setting bit WDT (IEN0.6) and by the next instruction setting
SWDT (IEN1.6). Bit WDT will automatically be cleared during the second machine cycle after
having been set. For this reason, setting SWDT bit has to be a one cycle instruction (e.g. SETB
SWDT). This double-instruction refresh of the watchdog timer is implemented to minimize the
chance of an unintentional reset of the watchdog.
The reload register WDTREL can be written to at any time, as already mentioned. Therefore, a
periodical refresh of WDTREL can be added to the above mentioned starting procedure of the
watchdog timer. Thus a wrong reload value caused by a possible distortion during the write
operation to the WDTREL can be corrected by software.
8.1.5 Watchdog Reset and Watchdog Status Flag
lf the software fails to clear the watchdog in time, an internally generated watchdog reset is entered
at the counter state 7FFCH. The duration of the reset signal then depends on the prescaler
selection (either 4, 8, 64, or 128 cycles). This internal reset differs from an external one only in so
far as the watchdog timer is not disabled and bit WDTS (watchdog timer status, bit 6 in special
function register IP0) is set. Figure 8-2 shows a block diagram of all reset requests in the C509-L
and the function of the watchdog status flags. The WDTS flag is a flip-flop, which is set by a
watchdog timer reset and cleared by an external HW reset. Bit WDTS allows the software to
examine from which source the reset was activated. The watchdog timer status flag can also be
cleared by software.
Figure 8-2
Watchdog Timer Status Flags and Reset Requests
Semiconductor Group
8-5
1997-10-01
Fail Save Mechanisms
C509-L
8.2
Oscillator Watchdog
The C509-L has a oscillator watchdog unit that is fully compatible with the SAB 80C517A's oscillator
watchdog.
The oscillator watchdog unit serves three functions:
– Monitoring of the on-chip oscillator's function.
The watchdog supervises the on-chip oscillator's frequency; if it is lower than the frequency
of the auxiliary RC oscillator in the watchdog unit, the internal clock is supplied by the RC
oscillator and the device is brought into reset; if the failure condition disappears (i.e. the onchip oscillator has a higher frequency than the RC oscillator), the part executes a final reset
phase of appr. 0.5 ms in order to allow the oscillator to stabilize; then the oscillator watchdog
reset is released and the part starts program execution again.
– Restart from the hardware power down mode.
If the hardware power down mode is terminated the oscillator watchdog has to control the
correct start-up of the on-chip oscillator and to restart the program. The oscillator watchdog
function is only part of the complete hardware power down sequence; however, the watchdog
works identically to the monitoring function.
– Fast internal reset after power-on.
In this function the oscillator watchdog unit provides a clock supply for the reset before the onchip oscillator has started. In this case the oscillator watchdog unit also works identically to
the monitoring function.
If the oscillator watchdog unit shall be used it must be enabled (this is done by applying high level
to the control pin OWE).
Figure 8-3 shows the block diagram of the oscillator watchdog unit. It consists of an internal RC
oscillator which provides the reference frequency for the comparison with the frequency of the onchip oscillator. The RC oscillator can be enabled/disabled by the control pin OWE. If it is disabled
the complete unit has no function.
The SFR IP0 contains a status flag of the oscillator watchdog as shown below.
Special Function Register IP0 (Address A9H)
Bit No.
A9H
7
6
OWDS WDTS
5
IP0.5
4
IP0.4
Reset Value : 00H
3
IP0.3
2
IP0.2
1
IP0.1
0
IP0.0
IP0
The shaded bits are not used in controlling the oscillator watchdog.
Bit
Function
OWDS
Oscillator watchdog timer status flag
Set by hardware when an oscillator watchdog reset occurred.
Can be cleared or set by software.
Semiconductor Group
8-6
1997-10-01
Fail Save Mechanisms
C509-L
Figure 8-3
Functional Block Diagram of the Oscillator Watchdog
The frequency coming from the RC oscillator is divided by 5 and compared to the on-chip oscillator's
frequency. If the frequency coming from the on-chip oscillator is found lower than the frequency
derived from the RC oscillator the watchdog detects a failure condition (the oscillation at the on-chip
oscillator could stop because of crystal damage etc.). In this case it switches the input of the internal
clock system to the output of the RC oscillator. This means that the part is being clocked even if the
on-chip oscillator has stopped or has not yet started. At the same time the watchdog activates the
internal reset in order to bring the part in its defined reset state. The reset is performed because
clock is available from the RC oscillator. This internal watchdog reset has the same effects as an
externally applied reset signal with the following exception: The watchdog timer status flag WDTS
(IP0.6) is not reset (the Watchdog Timer however is stopped) and bit OWDS is set. This allows the
software to examine error conditions detected by the watchdog timer even if meanwhile an oscillator
failure occurred.
The oscillator watchdog is able to detect a recovery of the on-chip oscillator after a failure. If the
frequency derived from the on-chip oscillator is again higher than the reference the watchdog starts
a final reset sequence which takes typ. 1 ms. Within that time the clock is still supplied by the RC
oscillator and the part is held in reset. This allows a reliable stabilization of the on chip oscillator.
After that, the watchdog toggles the clock supply back to the on-chip oscillator and releases the
reset request. If no external reset is applied in this moment the part will start program execution. If
an external reset is active, however, the device will keep the reset state until also the external reset
request disappears.
Furthermore, the status flag OWDS is set if the oscillator watchdog was active. The status flag can
be evaluated by software to detect that a reset was caused by the oscillator watchdog. The flag
OWDS can be set or cleared by software. An external reset request, however, also resets OWDS
(and WDTS).
Semiconductor Group
8-7
1997-10-01
Power Saving Modes
C509-L
9
Power Saving Modes
The C509-L provides three modes in which power consumption can be significantly reduced.
– Idle mode
The CPU is gated off from the oscillator. All peripherals are still provided with the clock and
are able to work.
– Power down mode
The operation of the C509-L is completely stopped and the oscillator is turned off. This mode
is used to save the contents of the internal RAM with a very low standby current. Power down
mode can be entered by software or by hardware.
– Slow-down mode
The controller keeps up the full operating functionality, but its normal clock frequency is
internally divided by eight. This slows down all parts of the controller, the CPU and all
peripherals, to 1/8 th of their normal operating frequency. Slowing down the frequency greatly
reduces power consumption.
All of these modes - a detailed description of each is given in the following sections - are entered by
software. Special function register PCON (power control register) is used to select one of these
modes.
These power saving modes, especially the power down mode, replace the hardware power down
supply for the internal RAM via a dedicated pin. During the power saving modes, the power supply
for the C509-L are all VCC pins. There is no further dedicated pin for power down supply.
For the C509-L several provisions have been made to quality it for both electrically noisy
environments and applications requiring high system security. In such applications unintentional
entering of the power saving modes must be absolutely avoided. A power saving mode would
reduce the controller’s performance (in the case of slow-down mode) or even stop any operation (in
the case of power down mode). This situation might be fatal for the system, which is controlled by
the microcontroller. Such critical applications often use the watchdog timer to prevent the system
from program upsets. Then, an accidental entering of the power saving modes would even stop the
watchdog timer and would circumvent the watchdog timer’s task of system protection.
Semiconductor Group
9-1
1997-10-01
Power Saving Modes
C509-L
9.1
Hardware Enable for the Use of the Power Saving Modes
To provide power saving modes together with effective protection against unintentional entering of
these modes, the C509-L has an extra pin disabling the use of the power saving modes. As this pin
will most likely be used only in critical applications it is combined with an automatic start of the
watchdog timer (see the description in section 7.8 “Fail Save Mechanisms”). This pin is called PE/
SWD (power saving enable/start watchdog timer) and its function is as follows:
PE/SWD = 1 (logic high level)
– Use of the power saving modes is not possible. The instruction sequences used for entering
these modes will not affect the normal operation of the device.
– lf and only if PE/SWD is held at high level during reset, the watchdog timer is started
immediately after reset is released.
PE/SWD = 0 (logic low level)
– All power saving modes can be activated as described in the following sections
– The watchdog timer has to be started by software if system protection is desired.
When left unconnected, the pin PE/SWD is pulled to high level by a weak internal pullup. This is
done to provide system protection by default.
The logic level applied to pin PE/SWD can be changed during program execution in order to allow
or block the use of the power saving modes without any effect on the on-chip watchdog circuitry;
(the watchdog timer is started only if PE/SWD is on high level at the moment when reset is released;
a change at PE/SWD during program execution has no effect on the watchdog timer; this only
enables or disables the use of the power saving modes.). A change of the pin’s level is detected in
state 3, phase 1. A Schmitt trigger is used at the input to reduce susceptibility to noise.
In addition to the hardware enable/disable of the power saving modes, a double-instruction
sequence which is described in the corresponding sections is necessary to enter power down and
idle mode. The combination of all these safety precautions provide a maximum of system
protection.
Application Example for Switching Pin PE/SWD
For most applications in noisy environments, components external to the chip are used to give
warning of a power failure or a turn off of the power supply. These circuits could be used to control
the PE/SWD pin. The possible steps to go into power down mode could then be as follows:
– A power-fail signal forces the controller to go into a high priority interrupt routine. This interrupt
routine saves the actual program status. At the same time pin PE/SWD is pulled low by the
power-fail signal.
– Finally the controller enters power down mode by executing the relevant double-instruction
sequence.
Semiconductor Group
9-2
1997-10-01
Power Saving Modes
C509-L
9.2
Power Saving Mode Control Register PCON
The SFR PCON is used for control of the power saving modes. It also contains two general purpose
flags, which can be used e.g. by software for power saving mode management.
Special Function Register PCON (Address 87H)
Bit No. MSB
7
87H
SMOD
Reset Value : 00H
6
5
4
3
2
1
LSB
0
PDS
IDLS
SD
GF1
GF0
PDE
IDLE
PCON
The shaded bits are not used for power saving mode control.
Bit
Function
PDS
Power down start bit
The instruction that sets the PDS flag bit is the last instruction before entering the
power down mode.
IDLS
IDLE start bit
The instruction that sets the IDSL flag bit is the last instruction before entering the
idle mode.
SD
Slow down bit
When set, the slow-down mode is enabled.
GF1
General purpose flag
GF0
General purpose flag
PDE
Power down enable bit
When set, starting the power down mode is enabled.
IDLE
Idle mode enable bit
When set, starting the idle mode is enabled.
Semiconductor Group
9-3
1997-10-01
Power Saving Modes
C509-L
9.3
Idle Mode
In idle mode the oscillator of the C509-L continues to run, but the CPU is gated off from the clock
signal. However, the interrupt system, the serial channels, the A/D converter, the oscillator
watchdog, the division/multiplication unit and all timers, except for the watchdog timer, are further
provided with the clock. The CPU status is preserved in its entirety: the stack pointer, program
counter, program status word, accumulator, and all other registers maintain their data during idle
mode.
The reduction of power consumption, which can be achieved by this feature, depends on the
number of peripherals running. lf all timers are stopped and the A/D converter and the division/
multiplication unit are not running, maximum power reduction can be achieved. This state is also the
test condition for the idle ICC in the DC characteristics.
Thus, the user has to take into account that the right peripheral continues to run or is stopped,
respectively, during idle. Also, the state of all port pins - either the pins controlled by their latches or
controlled by their secondary functions - depends on the status of the controller when entering idle.
Normally the port pins hold the logical state they had at the time idle was activated. lf some pins are
programmed to serve their alternate functions they still continue to output during idle if the assigned
function is on. This applies for the compare outputs as well as for the system clock output signal and
the serial interface in case the latter could not finish reception or transmission during normal
operation. The control signals ALE and PSEN are held at logic high levels (see table 9-1).
During idle, as in normal operating mode, the ports can be used as inputs. Thus, a capture or reload
operation as well as an A/D conversion can be triggered, the timers can be used to count external
events and external interrupts can be detected.
Semiconductor Group
9-4
1997-10-01
Power Saving Modes
C509-L
Table 9-1
Status of External Pins During Idle and Software Power Down Mode
Pins
Idle Mode
Software Power Down Mode
ALE
High
Low
PSEN
High
Low
Port 0
Float
Float
Port 1
Data / alternate outputs
Data / last output
Port 2
Address
Data
Port 3
Data / alternate outputs
Data / last output
Port 4
Data / alternate outputs
Data / last output
Port 5
Data / alternate outputs
Data / last output
Port 6
Data / alternate outputs
Data / last output
Port 9
Data / alternate outputs
Data / last output
The watchdog timer is the only peripheral which is automatically stopped during idle mode. The idle
mode makes it possible to “freeze” the processor’s status for a certain time or until an external event
causes the controller to go back into normal operating mode. Since the watchdog timer is stopped
during idle mode, this useful feature of the C509-L is provided even if the watchdog function is used
simultaneously.
lf the idle mode is to be used the pin PE/SWD must be held low. Entering the idle mode is to be done
by two consecutive instructions immediately following each other. The first instruction has to set the
flag bit IDLE (PCON.0) and must not set bit IDLS (PCON.5), the following instruction has to set the
start bit IDLS (PCON.5) and must not set bit IDLE (PCON.0). The hardware ensures that a
concurrent setting of both bits, IDLE and IDLS will not initiate the idle mode. Bits IDLE and IDLS will
automatically be cleared after having been set. lf one of these register bits is read the value shown
is zero (0). This double-instruction sequence is implemented to minimize the chance of
unintentionally entering the idle mode.
Note that PCON is not a bit-addressable register, so the above mentioned sequence for entering
the idle mode is to be done by byte handling instructions.
The following instruction sequence may serve as an example:
– ORLPCON,#00000001B;Set bit IDLE, bit IDLS must not be set
ORLPCON,#00100000B;Set bit IDLS, bit IDLE must not be set
The instruction that sets bit IDLS is the last instruction executed before going into idle mode.
Termination of the Idle Mode
– The idle mode can be terminated by activation of any enabled interrupt. The CPU operation
is resumed, the interrupt will be serviced and the next instruction to be executed after the RETI
instruction will be the one following the instruction that set the bit IDLS.
– The other possibility of terminating the idle mode is a hardware reset. Since the oscillator is
still running, the hardware reset is held active for only two machine cycles for a complete
reset.
Semiconductor Group
9-5
1997-10-01
Power Saving Modes
C509-L
9.4
Software Power Down Mode
In the software power down mode, the on-chip oscillator is stopped. Therefore, all functions are
stopped, only the contents of the on-chip RAM and the SFR’s are held. The port pins controlled by
their port latches output the values that are held by their SFR’S. The port pins which serve the
alternate output functions show the values they had at the end of the last cycle of the instruction
which initiated the power down mode; when enabled, the clockout signal (P1.6/CLKOUT) will stop
at low level. ALE and PSEN are held at logic low level (see table 9-1).
lf the software power down mode is to be used, the pin PE/SWD must be held low. Entering the
software power down mode is done by two consecutive instructions immediately following each
other. The first instruction has to set the flag bit PDE (PCON.1) and must not set bit PDS (PCON.6).
The following instruction has to set the start bit PDS and must not set bit PDE. The hardware
ensures that a concurrent setting of both bits, PDE and PDS, will not initiate the power down mode.
Bit PDE and PDS will automatically be cleared after having been set and the value shown when
reading one of these bits is always zero (0). This double-instruction sequence is implemented to
minimize the chance of unintentional entering the software power down mode, which could possibly
“freeze” the chip’s activity in an undesired status.
Note that PCON is not a bit-addressable register, so the above mentioned sequence for entering
the software power down mode is composed of byte handling instructions.
The following instruction sequence may serve as an example:
ORL
ORL
PCON,#00000010B
PCON,#01000000B
;Set bit PDE, bit PDS must not be set
;Set bit PDS, bit PDE must not be set
The instruction that sets bit PDS is the last instruction executed before going into power down
mode. lf idle mode and software power down mode are invoked simultaneously, the software power
down mode takes precedence.
The only exit from software power down mode is a hardware reset. Reset will redefine all SFR’s, but
will not change the contents of the internal RAM.
In the software power down mode, VCC can be reduced to minimize power consumption. Care must
be taken, however, to ensure that VCC is not reduced before the software power down mode is
invoked, and that VCC is restored to its normal operating level before software the power down mode
is terminated. The reset signal that terminates the software power down mode also frees the
oscillator. The reset should not be activated before VCC is restored to its normal operating level and
must be held active long enough to allow the oscillator to restart and stabilize (similar to power-on
reset).
Semiconductor Group
9-6
1997-10-01
Power Saving Modes
C509-L
9.5
Slow Down Mode
In some applications, where power consumption and dissipation is critical, the controller might run
for a certain time at reduced speed (e.g. if the controller is waiting for an input signal). Since in
CMOS devices there is an almost linear interdependence of the operating frequency and the power
supply current, a reduction of the operating frequency results in reduced power consumption.
In the slow down mode all signal frequencies that are derived from the oscillator clock are divided
by eight. This also includes the clockout signal at pin P1.6/CLKOUT.
lf the slow down mode is to be used the pin PE/SWD must be held low.
The slow down mode is entered by setting bit SD (PCON.4). The controller actually enters the slow
down mode after a short synchronization period (max. two machine cycles). The slow down mode
can be used together with idle and power down mode.
The slow down mode is disabled by clearing bit SD.
Semiconductor Group
9-7
1997-10-01
Power Saving Modes
C509-L
9.6
Hardware Power Down Mode
The C509-L has also a hardware power down mode. This mode can be initiated by an external
signal at the pin HWPD. This mode is referenced as hardware power down mode in opposite to the
program controlled software power down mode.
For a correct function of the hardware power down mode the oscillator watchdog unit including its
internal RC oscillator is needed. Therefore this unit must be enabled by pin OWE (OWE = high), if
the hardware power down mode shall be used. However, the control pin PE/SWD has no control
function for the hardware power down mode; it enables and disables only the use of all software
controlled power saving modes (slow down mode, idle mode, software power down mode).
The function of the hardware power down mode is as follows:
– The pin HWPD controls this mode. If it is on logic high level (inactive) the part is running in the
normal operating modes. If pin HWPD gets active (low level) the part enters the hardware
power down mode; as mentioned above this is independent of the state of pin PE/SWD.
HWPD is sampled once per machine cycle. If it is found active, the device starts a complete internal
reset sequence. This takes two machine cycles; all pins have their default reset states during this
time. This reset has exactly the same effects as a hardware reset; i.e.especially the watchdog timer
is stopped and its status flag WDTS is cleared. In this phase the power consumption is not yet
reduced. After completion of the internal reset both oscillators of the chip are disabled, the on-chip
oscillator as well as the oscillator watchdog's RC oscillator. At the same time the port pins and
several control lines enter a floating state as shown in table 9-2. In this state the power consumption
is reduced to the power down current IPD. Also the supply voltage can be reduced.
Table 9-2 also lists the voltages which may be applied at the pins during hardware power down
mode without affecting the low power consumption.
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Power Saving Modes
C509-L
Table 9-2
Status of all Pins During Hardware Power Down Mode
Pins
Status
Voltage Range at Pin During
HW-Power Down
P0, P1, P2, P3, P4, Floating outputs / disabled input function
P5, P6, P7, P8, P9
VSS ≤ VIN ≤ VCC
EA
active input
VIN = VCC or VIN = VSS
PE/SWD
active input, pull-up resistor disabled
during HW power down
VIN = VCC or VIN = VSS
XTAL1
active output
pin may not be driven
XTAL2
disabled input function
VSS ≤ VIN ≤VCC
PSEN/RDF, ALE
Floating outputs / disabled input function
(for test modes only)
VSS ≤ VIN ≤ VCC
VAREF, VAGND
active supply pins
VAGnd ≤ VIN ≤ VCC
OWE
active input; must be at high level for start- VIN = VCC
up after HW power down; pull up resistor or
disabled during HW-power down
(VIN = VSS)
RESET
active input; must be on high level if HW
power down is used
VIN = VCC
R0
Floating output
VSS ≤ VIN ≤ VCC
The power down state is maintained while pin HWPD is held active. If HWPD goes to high level
(inactive state) an automatic start up procedure is performed:
– First the pins leave their floating condition and enter their default reset state as they had
immediately before going to float state.
– Both oscillators are enabled (only if OWE = high). While the on-chip oscillator (with pins
XTAL1 and XTAL2) usually needs a longer time for start-up, if not externally driven (with
crystal approx. 1 ms), the oscillator watchdog's RC oscillator has a very short start-up time
(typ. less than 2 microseconds).
– Because the oscillator watchdog is active it detects a failure condition if the on-chip oscillator
hasn't yet started. Hence, the watchdog keeps the part in reset and supplies the internal clock
from the RC oscillator.
– Finally, when the on-chip oscillator has started, the oscillator watchdog releases the part from
reset after it performed a final internal reset sequence and switches the clock supply to the
on-chip oscillator. This is exactly the same procedure as when the oscillator watchdog detects
first a failure and then a recovering of the oscillator during normal operation. Therefore, also
the oscillator watchdog status flag is set after restart from hardware power down mode.
When automatic start of the watchdog was enabled (PE/SWD connected to V CC ), the
Watchdog Timer will start, too (with its default reload value for time-out period).
The SWD-Function of the PE/SWD pin is sampled only by a hardware reset. Therefore at least one
Power On Reset has to be performed.
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Power Saving Modes
C509-L
9.7
Hardware Power Down Mode Reset Timing
The following figures show timing diagrams for entering (figure 8-1) and leaving (figure 8-2) the
hardware power down mode. If there is only a short signal at pin HWPD (i.e. HWPD is sampled
active only once), then a complete internal reset is executed. Afterwards the normal program
execution starts again (figure 8-3).
Note: Delay time caused by internal logic is not included.
The RESET pin overrides the hardware power down function, i.e. if RESET becomes active during
hardware power down it is terminated and the device performs the normal reset function. Thus, pin
RESET has to be inactive during hardware power down mode.
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Power Saving Modes
C509-L
Figure 9-1
Timing Diagram of Entering Hardware Power Down Mode
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Power Saving Modes
C509-L
Figure 9-2
Timing Diagram of Leaving Hardware Power Down Mode
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Power Saving Modes
C509-L
Figure 9-3
Timing Diagram of Hardware Power Down Mode, HWPD-Pin is active for only one Cycle
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Bootstrap Loader
C509-L
10
The Bootstrap Loader
The C509-L includes a bootstrap mode, which is activated by setting the PRGEN pin at logic high
level at the rising edge of the RESET or the HWPD signal (bit PRGEN1=1). In this mode software
routines of the bootstrap loader, located at the addresses 0000H to 01FFH in the boot ROM will be
executed. Its purpose is to allow the easy and quick programming of the internal XRAM (F400H to
FFFFH) via 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 serial routines of the
bootstrap loader may be replaced by own custom software 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 consists of three functional parts which represent the three phases as
described below.
10.1 General Functions of the Bootstrap Loader
Phase I : Check for existing custom software in the external FLASH memory and execute it.
Phase II : Establish a serial connection and automatically synchronize to the transfer speed (baud
rate) of the serial communication partner (host).
Phase III : Perform the serial communication to the host. The host controls the bootstrap loader by
sending header informations, which select one of four operating modes.
These modes are:
Mode 0: Transfer a custom program from the host to the XRAM (F400H - FFFFH).
This mode returns to the beginning of phase III.
Mode 1: Execute a custom program in the XRAM at any start address from F400H to
FFFFH.
Mode 2: Check the contents of any area of the external FLASH memory by calculating
a checksum. This mode returns to the beginning of phase III.
Mode 3: Execute a custom program in the FLASH memory at any start address
beyond 0200H (at addresses 0000H to 01FFH the boot-ROM is active).
The 3 phases of the bootstrap loader program and their connections are illustrated in figure 10-1.
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Figure 10-1
The Three Phases of the Bootstrap Loader
The serial communication, which is activated in phase II is performed with the integrated serial
interface 0 of the C509-L. Using a full- or half-duplex serial cable (RS232) the MCU must be
connected to the serial port of the host computer as shown in figure 10-.
Figure 10-2
Bootstrap Loader Interface to the PC
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The serial transfer operates in asynchronous mode with the serial parameters 8N2 (eight data bits,
no parity and two stop bits). The baud rate however can be varied by the host in a wide range,
because the bootstrap loader does an automatic synchronization in phase II.
The bootstrap loader itself does not use any of the implemented interrupts of the MCU for its work.
But for further custom program execution in the bootstrap mode two interrupts are supported. These
are the interrupts for the timer 0 (TIMER0) and for the serial interface 0 (SINT0). As the interrupt
vectors are located in the address area of the bootstrap loader (0000H - 01FFH), the appropriate
interrupt vector addresses are routed by the bootstrap loader via a LJMP instruction to a reserved
XRAM area at F400H - F41FH as shown below:
TIMER0:
SINT0:
usually at 000BH is routed to F400H in XRAM
usually at 0023H is routed to F410H in XRAM
At these addresses (F400H - F40FH and F410H - F41FH) the user specified interrupt routines can
be loaded to handle the interrupts in a user defined way. To avoid unexpected software behavior
when these interrupts are used, the reserved memory area should be used only by interrupt
handling routines. Notice: In this case the XRAM for custom programs is reduced to F420H FFFFH. If there is no need of these interrupts, the reserved memory area can be programmed with
custom software.
It is recommended not to activate other interrupts than TIMER0 and SINT0, because this could lead
to uncontrolled software execution in the interrupt vector area (0000H - 0100H)!
10.2
Phase I: Check for Existing Custom Software in the External FLASH Memory
The first action of the bootstrap trap loader is to check two blocks in the external FLASH memory for
the existence of custom software. If the check is successful, the custom software is started directly.
If no software is found, phase II is entered to establish a serial communication with the connected
host. This feature can be used to protect the external FLASH memory contents against
unauthorized in-system reading and writing in the bootstrap mode. The security check can be used
if needed, but can also be skipped as well, as described in the next section.
10.2.1 Custom Software Check by the Info Block
For the above mentioned custom software two memory sectors (sector A: at C000H, sector B: at
6000H) of the external FLASH memory are reserved. For activation of the FLASH memory check,
an info block is required, which has to be written at the beginning of the corresponding external
FLASH memory sector. The structure of the info block is shown in figure 10-3.
The sector addresses C000H and 6000H are valid for the C509-L devices with stepping code CA
and later.
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Bootstrap Loader
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Info Block Byte
Description
ID byte #1 - #4
Four ID bytes which mark the external FLASH memory
sector as programmed.
startaddress (high, low)
The start address, where the custom program starts.
blocklength (high, low)
The length of the memory block, which is filled with the
custom program code.
checksum #1, #2
Two checksum bytes for the external FLASH memory
block
memory area for custom software The area for the custom program starting at C00AH in
sector A and 600AH in sector B
Figure 10-3
The Structure of the FLASH Memory Info Block
The info block starts with a fixed sequence of four identification bytes (ID bytes). They mark the
corresponding memory sector as custom programmed. If the ID bytes are not present at the
beginning of the info block, the bootstrap loader assumes, that the corresponding sector is not
custom programmed.
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The four identification bytes must be absolutely definite to prevent the bootstrap loader from
recognizing normal program code as identification bytes. Therefore the four bytes represent a not
senseful instruction sequence in 8051-code, which should never occur in normal programs. The
definition of the identification bytes is shown in table 10-1.
Table 10-1
ID Bytes of the Info Block
ID byte
Value
8051-code
#1
23H
RL A
#2
03H
RR A
#3
33H
RLC A
#4
13H
RRC A
To check, if the custom software in the relevant sector is functional, the bootstrap loader calculates
a checksum consisting of two independent checksum bytes over the appropriate memory area. This
area begins at the address startaddress and has a length of blocklength. The two generated
checksum bytes are compared with checksum #1 and #2 of the info block. If the checksums are
equal, the bootstrap loader starts the custom routine in this sector at the address startaddress.
The bootstrap loader starts checking sector A. If either the identification bytes or the checksums of
sector A are not correct, the checking procedure is done with sector B of the external FLASH
memory. The check of two sectors (A and B) is necessary for a maximum of security, e.g. if the
custom software in one sector is not functional. This can happen e.g., if the programming of the
corresponding external FLASH memory sector suddenly is interrupted by the cause of a power
failure.
When the check fails in both sectors, the bootstrap loader leaves phase I and enters phase II to
establish the serial communication to a connected host via serial interface 0.
If the customer does not want to use this external FLASH sector check, he can override it by
programming other values than the four ID bytes in the corresponding FLASH memory addresses
in sector A and B. If this is done, the remaining bytes of the two external FLASH memory sectors
may be used for normal program execution as well.
The flowchart in figure 10-4 shows the detailed actions of the bootstrap loader in phase I.
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C509-L
Figure 10-4
Flowchart of Phase I Actions
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10.2.2 Checksum Calculation
The external FLASH memory check in phase I uses a checksum algorithm, which is based on a
continuous addition and 8-bit-left-rotation of all relevant data bytes. The data in the corresponding
FLASH memory area is split into two parts, on which an extra checksum is built. This is done to
reach a maximum of data security. Checksum #1 is build by bytes at odd addresses and
checksum #2 is calculated with bytes at even addresses. The checksum calculation itself is
described in the flowchart in figure 10-5.
Figure 10-5
Flowchart of the Checksum Calculation for the external FLASH Memory
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10.3
Phase II: Automatic Serial Synchronization with the Host
When the bootstrap loader leaves phase I and enters phase II, the synchronization procedure
between MCU and host will be started. The synchronization must be handled by the host system as
shown in figure 10-6.
Figure 10-6
The Synchronization between MCU and Host
After receiving the testbyte from the host, the bootstrap loader calculates the actual baud rate and
activates the baud rate generator of the serial interface 0. When the synchronization is
accomplished, the MCU sends an acknowledge byte (55H) back to the host. The baud rate
calculation works correctly only in a specific range of baud rates. If the synchronization fails, the
baud rates between MCU and host are different, and the acknowledge code from the MCU can't be
received properly by the host. In this case, the host software may give a message to the customer,
e.g. that he has to repeat the synchronization procedure.
Attention: the bootstrap loader doesn't recognize, if the synchronization was correct. It always
enters phase III after sending the acknowledge byte. Therefore, if synchronization fails, a reset of
the MCU has to be invoked, to restart the bootstrap loader for a new synchronization attempt.
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C509-L
10.3.1 Automatic Synchronization Procedure
In phase II the bootstrap loader starts the serial communication with the host via the serial interface
0 of the C509-L. The interface of the MCU is set to mode 3, which means asynchronous
transmission with the data format 8N2 (eight data bits, no parity, two stop bits). The host has to use
the same serial parameters.
For the baud rate synchronization of the MCU to the fixed baud rate of the host, the bootstrap loader
waits for the testbyte (00H), which has to be sent by the host. By polling the receive port of the serial
interface 0 (P3.0 / RxD) the bootstrap loader measures the receiving time of the test byte by using
timer 0 as shown in the figure 10-7.
Figure 10-7
Measuring the receive time of a zero byte by using Timer 0
The resulting timer value is used to calculate the reload value for the 10-bit baud rate generator of
the serial interface 0 (S0REL). This calculation needs two formulas: the correlation between the
baud rate (Bd) and the reload value (S0REL) depending on the oscillator frequency of the MCU
(fosc)
fosc
Bd = ----------------------------------------------------32 × ( 1024 – S0REL )
(1)
and the relation between the baud rate (Bd) and the value of timer 0 (T0) depending on the oscillator
frequency (fosc) and the number of received bits (Nb).
fosc × Nb
Bd = -----------------------T0 × 12
(2)
Equations (1) and (2) and resolving the result to S0REL leads to the formula
T0 × 12
S0REL = 1024 – ------------------32 × Nb
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which is independent from the oscillator frequency of the MCU (fosc). The value of Nb is nine,
because one start bit plus eight data bits are measured. The resulting formula then is
T0 × 12
S0REL = 1024 – -----------------32 × 9
This equation contains the constant factor
12
--------------- = 0.0417
32 × 9
So the formula can be written as
S0REL = 1024 – 0.0147 × T0
To avoid complicated float point arithmetic the factor 0.0417 is scaled by multiplying it with 4096
(result is 171) and then performing an integer multiplication with T0. In the next step the product is
rescaled by a integer division with 4096, which can be simply achieved by a twelve bit right-shift
operation. The final formula for calculating the reload value S0REL including scaling and rescaling
is therefore:
171 × T0
S0REL = 1024 – --------------------4096
(3)
Additionally, the result of the division is rounded by a simple bit comparison of the last right shifted
bit. After setting S0REL to the calculated value and activating the baud rate generator of the serial
interface 0, the bootstrap loader sends an acknowledge byte (55H) to the host. If this byte is
received correctly, it will be assured, that both serial interfaces are working with the same baud rate.
The flowchart in figure 10-8 shows the calculation of the reload value S0REL for the baud rate
generator of the serial interface 0.
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Figure 10-8
Calculation Scheme of the S0REL Value
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C509-L
10.3.2 Baud Rates for Correct Synchronization
The automatic baud rate synchronization will work correctly only in a specific range of baud rates,
which depends on the oscillator frequency fosc of the C509-L and the resolution of the timer 0 (T0).
The minimum baud rate (Bdmin) results in the possible underflow of SFR S0REL when the value of
T0 gets greater than 24556. In this case the value of SFR S0REL, corresponding formula (3), gets
below zero, which leads to a underflow of the S0REL register and therefore to a incorrect baud rate
of the baud rate generator. The formula for calculating this underflow margin is derived from formula
(1) and is reduced to
fosc
Bd min = -------------32768
The theoretical maximum baud rate (Bdhigh) can be attained if S0REL is set to its maximum value
of 1023. In this case formula (1) reduces to
fosc
Bd high = ---------32
The real maximum baud rate (Bdmax) is smaller, because of the decreasing resolution of S0REL and
T0 at higher baud rates, This causes an increasing deviation between the host baud rate and the
MCU baud rate. To perform a correct transfer between the MCU and the host without transmission
errors, the deviation Fb of the host baud rate to the MCU baud rate may not exceed 2.5%.
Bd host – Bd MCU
Fb = 0.025 ≤ -------------------------------------Bd host
Between Bdmin and Bdmax every host baud rate can be synchronized successfully by the bootstrap
loader. Above Bdmax only discreet baud rates with a deviation of less than 2.5 % may be used.
Table 10-2 shows the guaranteed range of baud rates Bdmin to Bdmax and typical functional host
baud rates above Bdmax for some MCU clock rates fosc.
Table 10-2
Typical Baudrate Selections
MCU clock rate
fosc
Minimum baud rate
Bdmin
Maximum baud rate
Bdmax (Fb 2,5%)
Functional higher baud
rates
8 MHz
250 baud
6580 baud
9600, 19200 baud
12 MHz
370 baud
9380 baud
9600, 19200 baud
16 MHz
490 baud
12830 baud
19200, 38400 baud
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C509-L
10.4
Phase III: Serial Communication with the Host
After the successful synchronization with the host the bootstrap loader enters phase III, in which it
communicates with the host to select the desired operating modes. This communication between
host and bootstrap loader in phase III is based on different types of transfer blocks. Prior to the
description of the phase III operations, the transfer blocks are described in the next section.
10.4.1 Block Transfer Protocol
The communication between the host and the bootstrap loader is done by a simple transfer
protocol, which is based on a specified block structure. The communication is nearly unidirectional,
that means, that the host is sending several transfer blocks and the bootstrap loader is just
confirming them by sending back single acknowledge or error bytes. The MCU itself does not send
any transfer blocks. Figure 10-9 shows the general format of the transfer block.
Format Item
Description
blocktype
This byte determines how data in the data area field
has to be interpreted.
The implemented blocktypes are:
00H
Type: “HEADER”
01H
Type: “DATA”
02H
Type: “END OF TRANSMISSION” (EOT)"
data area
This area contains a number of bytes which represent
the data of the transfer block. The number of bytes in
the data area may range between 00H and 7CH.
checksum
For safety purposes a checksum is build over
blocktype and data area field and sent after the data
area.
Figure 10-9
Basic Structure of a Bootstrap Loader Transfer Block
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A transfer block is built by the host depending on the data (header or program data) it contains. For
safety purposes the host calculates a simple checksum of the whole block (blocktype and data
area) to attach it at the end of the block. The checksum must be generated by EXOR-ing all bytes
of the transfer block with themselves. Every time the bootstrap loader receives a transfer block, it
recalculates the checksum of the received bytes (blocktype and data area) and compares it with
the attached checksum. If the comparison fails, the bootstrap loader is rejecting the transfer block
by sending back a checksum error byte (FEH) to the host. Another possible error is a wrong block
type. In this case the bootstrap loader sends back a block error byte (FFH) to the host. In both error
cases the bootstrap loader awaits the actual transfer block from the host again. If a block is received
correctly, an acknowledge byte (55H) is sent to the host.
Table 10-3
Confirmation Bytes of the Bootstrap-Loader
Receive status
Transmitted code to host
Acknowledge
55H
Block Error
FFH
Checksum Error
FEH
Three types of transfer blocks depending on the value of blocktype are implemented in the transfer
protocol. Table 10-4 gives an overview of these block types. The detailed structures of the blocks
are described in the following sections.
Table 10-4
Types of Transfer Blocks
Block Name
blocktype
Description
Header Block
00H (HEADER)
This block always has a length of 8 bytes (including the
attached checksum) and contains special information in the
data area, which selects the operating mode of the
bootstrap loader in phase III.
Data Block
01H (DATA)
This block is used in operating mode 0 to transfer a portion
of normal data in the data area (e.g. program code) from
the host to the XRAM of the MCU. The length of this block
depends on the information given in the header block
before.
EOT Block
02H (EOT)
This block is used to indicate the end of a data transmission
in operating mode 0. It contains the last bytes of the
transferred data. The length of this block depends on the
information given in a header block before.
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10.4.1.1 Header Block Definition
The header block from the host, which contains the mode number and additional data to start the
selected operating mode, is a normal transfer block with the block type HEADER (00H) and a fixed
length of eight bytes (including the attached checksum of the transfer block). Figure 10-10 shows
the general structure of this header block is shown below.
Format Item
Description
mode
This field contains the number of the operating mode:
00H Load custom program into the XRAM memory.
01H Jump to the XRAM memory at the specified
address startaddress.
02H Calculate the checksum of a specified part of the
external FLASH memory which is defined by
startaddress and datalength.
03H Jump to the FLASH memory at the specified
address startaddress.
startaddress
This 16-bit address defines the start address either in
XRAM or in ext. FLASH memory. The first byte to be
transmitted is the high order byte of the 16-bit address.
XXH
These bytes have a different meaning depending on the
mode byte of a header block. The detailed definition of
these bytes is given in figures 10-11, 10-18, 10-21, and
10-24.
Figure 10-10
Structure of the HEADER Block
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10.4.1.2 Data and EOT Block Definition
Data and EOT transfer blocks are used by the bootstrap loader to transfer data from the host to the
XRAM of the MCU. A data block contains a bulk of data, which has to be copied to the XRAM
beginning at an address which is defined by startaddress of a preceding header block. The number
of data bytes is also specified by the blocklength field of a proceeding header block.
The EOT block contains the last bytes of a data transmission to the XRAM. The number of the
remaining relevant bytes in the EOT block is given in no. of bytes.
Figure 10-11 shows the structure of Data and EOT block.
Figure 10-11
Data Block and EOT Block Structure
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10.4.2 Operating Mode Selection
When the bootstrap loader enters phase III, it first waits for an eight byte long header block from the
host, which will be confirmed with an acknowledge byte (55H). The header block contains the
information for the selection of the operating mode. Depending on this data the bootstrap loader
selects and activates the desired operating mode. This select procedure shows the block diagram
in figure 10-12.
Figure 10-12
Operating Mode Selection Procedure
If the MCU receives an incorrect header block, e.g. because of a bad serial transmission, the
bootstrap loader sends, instead of an acknowledge byte, a checksum- or block error byte (see
table 10-3) to the host and awaits the header block again. In this case the host may react by
resending the header block or by releasing a message to the customer.
The flowchart in figure 10-13 shows the structure of the phase III bootstrap loader part in detail.
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Figure 10-13
Flowchart of Phase III
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10.4.2.1 Selection of Operating Mode 0
Operating mode 0 is used to transfer a program from the host to the XRAM of the MCU via serial
interface. The header block, which has to be prepared and sent by the host for the activation of
operating mode 0 must have the structure as shown in figure 10-11.
Figure 10-14
Header Block for Operating Mode 0
The operating mode 0 header block transfers the 16-bit XRAM startaddress for the following data
blocks, the number of data bytes in the following data or EOT blocks (blocklength), and a
checksum byte.
After confirming the received header block, the bootstrap loader enters mode 0, in which the desired
data is transmitted from the host to the XRAM of the MCU using the two transfer blocks of the types
DATA and EOT, which are shown in figure 10-11.
The complete communication for mode 0 (including entering mode 0) between the host and the
MCU after the synchronization shows the block diagram in figure 10-15.
If an error occurs while transmitting data blocks, the host software has to react on error codes, sent
by the bootstrap loader when rejecting a block. This case is illustrated in the block diagram of
figure 10-16.
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Figure 10-15
Operating Mode 0 Communication Structure
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Figure 10-16
Handling Transmission Errors in Operating Mode 0
If the host sends a header block or a block that is not implemented in the protocol (a block type
number higher than 02H), the bootstrap loader reacts in a similar way as described in the figure
above, with the exception, that now a block error code (FEH) is sent to the host. It is up to the host
software to handle this error properly.
The bootstrap loader flowchart of the complete transfer protocol of mode 0 is shown in figure 10-17.
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Figure 10-17
Bootstrap Loader Flowchart of Operating Mode 0
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10.4.2.2 Selection of Operating Mode 1
Mode 1 is used to execute a custom program in the XRAM of the MCU at a given start address. The
header block, which has to be prepared and sent by the host for the activation of operating mode 1
has the structure as shown in figure 10-18.
Figure 10-18
Header Block for Operating Mode 1
The operating mode 1 header block transfers the 16-bit XRAM startaddress for program execution
in the XRAM, three dummy bytes, and a checksum byte.
After sending the appropriate header block for mode 1, no further serial communication is
necessary. The block diagram for the communication between the host and the MCU is shown in
figure 10-19:
Figure 10-19
Operating Mode 1 Communication Structure
Mode 1 swaps the XRAM to code memory by setting the corresponding swap-bit in SFR SYSCON1
and starts the program execution in the XRAM at any start address given in the header block at
startaddress.
Note: If the supported interrupts TIMER 0 and SINT 0 are used as described in section 10.1, the
XRAM area from F400H to F41FH is reserved for interrupt handling routines. Therefore
startaddress has to be greater than or equal to F420H.
The corresponding bootstrap loader flowchart of mode 1 is shown in figure 10-20.
Semiconductor Group
10-23
1997-10-01
Bootstrap Loader
C509-L
Figure 10-20
Bootstrap Loader Flowchart of Operating Mode 1
10.4.2.3 Selection of Operating Mode 2
Mode 2 is used to calculate a checksum of an external FLASH memory sector beginning at a
startaddress with the specified length datalength. The header block, which has to be prepared
and sent by the host for the activation of operating mode 2 is shown in figure 10-21.
Figure 10-21
Header Block for Operating Mode 2
The operating mode 2 header block transfers the 16-bit startaddress of the external FLASH
memory block, which has to be checked, the number of bytes (datalength), which have to be
checked beginning at startaddress, a dummy byte, and a checksum byte.
Mode 2 calculates a checksum of any area of the external FLASH memory starting at startaddress
with a length of datalength (see also section 10.2.2). The endaddress of the corresponding
memory block is startaddress + datalength. The two calculated checksum bytes are compared
with two fixed checksum values which must be placed at the end of the checked external FLASH
memory block, that is at addresses startaddress + datalength + 1 and startaddress + datalength
+ 2. If these checksum values are equal to the calculated checksums, an acknowledge byte (55H)
is sent to the host. Otherwise the checksum error code (FEH) is transmitted to the host.
Semiconductor Group
10-24
1997-10-01
Bootstrap Loader
C509-L
The block diagram in figure 10-22 shows the mode 2 checksum calculation in operating mode 2.
Figure 10-22
Operating Mode 2 Communication Structure
Semiconductor Group
10-25
1997-10-01
Bootstrap Loader
C509-L
Figure 10-23 shows the bootstrap loader flowchart of operating mode 2.
Figure 10-23
Bootstrap Loader Flowchart of Operating Mode 2
Semiconductor Group
10-26
1997-10-01
Bootstrap Loader
C509-L
10.4.2.4 Selection of Operating Mode 3
Mode 3 is used to execute a custom software in the external FLASH memory at any start address.
The header block, which has to be prepared and sent by the host for the activation of operating
mode 3 has the structure as shown in figure 10-24.
Figure 10-24
Header Block for Operating Mode 3
Mode 3 performs a direct program execution at a given startaddress, which is sent in the header
block. After sending the appropriate header block no further serial communication is necessary for
this mode. The block diagram for the communication between the host and the MCU in mode 3 is
shown in figure 10-25.
Figure 10-25
Operating Mode 3 Communication Structure
Note: The start address startaddress has to be greater than 200H, because in the bootstrap
mode the bootstrap loader overlaps the code address area of the external FLASH memory
from 0000H to 01FFH.
Semiconductor Group
10-27
1997-10-01
Bootstrap Loader
C509-L
Figure 10-26 shows the bootstrap loader flowchart of operating mode 3 as flowchart:
Figure 10-26
Bootstrap Loader Flowchart of Operating Mode 3
Semiconductor Group
10-28
1997-10-01
Bootstrap Loader
C509-L
10.5 Description of the Bootstrap Loader Subroutines
This section describes the software of the bootstrap loader with its most important subroutines and
start addresses, which can be used by the customer for own purposes. This technical reference is
valid for C509-L parts with a stepping code “CA” or later.
Table 10-5 shows the subroutines of the bootstrap loader which can be used by the customer, when
executing custom programs.
Table 10-5
Bootstrap Loader Subroutines - Survey
Address Function
Registers
Description
000EH
SendByte
In : A - Byte to send
Out : None
Send a byte to the serial interface 0
0016H
SendAckn
In : None
Out : None
Send an acknowledge code (55H) to
the serial interface 0
001BH
SendBlockErr
In : None
Out : None
Send a block error code (FFH) to the
serial interface 0
0074H
CalcBaudRate
In
: TH0/TL0 - measured
value for test byte in
T0
Out : R1/R2 value for S0REL
Calculate the value for the 10 bit baud
rate generator reload register S0REL
of the serial interface 0 depending on
the value of T0 (TH0/TL0) for receiving
the test byte (00H)
00A6H
CheckBaud
In : None
Out : None
The complete baud rate
synchronization:
1. Prepare the timer 0 for
measurement
2. Wait for the test byte from host
3. Measure the time between the start
bit and the stop bit
4. Calculate the baudrate from the
value of timer 0 (T0)
5. Initialize the serial interface 0 by
setting the baud rate and the serial
parameters (8N2)
6. Send an acknowledge code (55H) to
the host
Semiconductor Group
10-29
1997-10-01
Bootstrap Loader
C509-L
Table 10-5
Bootstrap Loader Subroutines - Survey (cont’d)
Address Function
Registers
Description
00C7H
GetBlock
In : R7 - block length
Out : None
Get an amount (in R7) of data bytes
from the host and save it to a
temporary buffer starting at address
70H and ending at address FFH. The
last received byte contains the
checksum of the data block. Examine
the sent checksum and send back a
checksum error code, if it is incorrect.
00E9H
CalcChks
In
Calculate the checksum of the data
block starting at address in R0 with a
length of R1. The checksum is saved in
A.
00F0H
CalcChksFLASH In
: DPTR - start address
of the area in the
FLASH memory
R4/R5 - length of the
FLASH memory area
Out : R0 - calculated
checksum #1
R1 - calculated
checksum #2
Calculate the special checksum of an
area in the FLASH memory starting at
address in DPTR with a length of R4/
R5 (high, low). The checksums #1 and
#2 are saved in R0 and R1.
0119H
CheckFLASH
In
: R2/R3 - start address
of corresponding
FLASH memory
block
Out : C - carry flag
Check if the FLASH memory block
starting at address R2/R3 contains a
functional custom program.
1. Check the ID bytes of the FLASH
memory block
2. Calculate the checksum of the given
memory block
3. Set the carry flag if no custom
program exists
0161H
Block2XRAM
In
Copy the contents of the temporary
buffer starting at address in R0 with a
length of R1 to the actual address
(DPTR) in the XRAM. The data pointer
DPTR is incremented automatically.
Semiconductor Group
: R0 - start address of
the temporary buffer
with length R1
Out : A - calculated
checksum
: R0 - start address of
the temporary buffer
R1 - length of the
buffer
DPTR - actual
address in the XRAM
Out : DPTR - actual
address in the XRAM
10-30
1997-10-01
Bootstrap Loader
C509-L
Table 10-5
Bootstrap Loader Subroutines - Survey (cont’d)
Address Function
Registers
Description
0168H
CheckHeader
In
: R0 - start address of
the temporary buffer
Out : R1 - operating mode
R2/R3, DPTR header data
startaddress
R4/R5 - header data
datalength
R7 - header data
blocklength
C - Carry flag
Analyze the received header and save
the header data into the corresponding
registers. If the checked block is not of
type HEADER, a block error code
(FFH) is sent to the host and the carry
flag C is set.
018AH
SendCheckErr
In : None
Out : None
Send a checksum error code to the
serial interface 0
018FH
Mode0
In
: DPTR - start address
of XRAM to copy a
custom program
R7 - length of the data
blocks received via
serial interface 0
Out : DPTR - actual
address in the XRAM
Activate operating mode 0. The header
data must be received or the registers
DPTR and R7 must be set manually,
before this routine can work correctly.
01B1H
Mode1
In
: DPTR - address to
start a custom
program in the XRAM
Out : None
Activate operating mode 1, that is to
start custom program in the XRAM at
address in DPTR. Attention: This
routine does not return, when finished.
01BBH
Mode2
In
: DPTR - start address
of the area in the
FLASH memory
R4/R5 - length of the
FLASH memory area
Out : None
Activate operating mode 2, that is to
calculate a special checksum of a
FLASH memory area given by the start
address in DPTR and the area length
in R4/R5.
01D6H
Mode3
In
Activate operating mode 3, that is to
start a custom program in the FLASH
memory at address in DPTR.
Attention: This routine does not return,
when finished.
Semiconductor Group
: DPTR - address to
start a custom
program in the
FLASH memory
Out : None
10-31
1997-10-01
Bootstrap Loader
C509-L
The bootstrap loader is sequentially working through the three phases. The addresses given in
table 10-6 allow the customer to step into the bootstrap loader in several phases.
Table 10-6
Further Bootstrap Loader Reference Addresses
Address Function
Description
0000H
Main
Start the complete bootstrap loader
0026H
LookFLASH1
Phase I: Search for a functional custom program in the ext. FLASH
memory sectors A and B
0035H
LookFLASH2
Phase I: Search for a functional custom program only in the ext.
FLASH memory sector B
0044H
PrepSerial
Phase II: Initialize the serial interface 0 and synchronize it to the host
baud rate
004AH
WaitHeader
Phase III: Wait for the header to select the operating mode
004FH
Header
Phase III: Check the header block information and save it in specific
registers
0054H
Jump2Mode
Phase III: Select and activate the operating mode given in register R1
Semiconductor Group
10-32
1997-10-01
Device Specifications
C509-L
11
Device Specifications
11.1 Absolute Maximum Ratings
Ambient temperature under bias (TA) .........................................................
Storage temperature (Tstg) ..........................................................................
Voltage on VCC pins with respect to ground (VSS) .......................................
Voltage on any pin with respect to ground (VSS) .........................................
Input current on any pin during overload condition.....................................
Absolute sum of all input currents during overload condition .....................
Power dissipation........................................................................................
– 40 to 110 °C
– 65 °C to 150 °C
– 0.5 V to 6.5 V
– 0.5 V to VCC +0.5 V
– 10 mA to 10 mA
I 100 mA I
1W
Note: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent
damage of the device. This is a stress rating only and functional operation of the device at
these or any other conditions above those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for longer
periods may affect device reliability. During overload conditions (VIN > VCC or VIN < VSS) the
Voltage on VCC pins with respect to ground (VSS) must not exceed the values defined by the
absolute maximum ratings.
11.2 DC Characteristics
TA = 0 to 70 °C
for the SAB-C509
TA = – 40 to 85 °C for the SAF-C509
VCC = 5 V + 10%, – 5%; VSS = 0 V
Parameter
Symbol
Limit Values
min.
max.
Unit
Test Condition
Input low voltage
(except EA, RESET, HWPD)
VIL
– 0.5
0.2 VCC –
0.1
V
–
Input low voltage (EA)
VIL1
– 0.5
0.2 VCC –
0.3
V
–
Input low voltage (HWPD,
RESET)
VIL2
– 0.5
0.2 VCC
V
–
Input low voltage (CMOS)
(ports 0 - 9)
VILC
– 0.5
0.3 VCC
V
–
Input high voltage (except
RESET, XTAL2 and HWPD
VIH
0.2 VCC +
0.9
VCC + 0.5
V
–
Input high voltage to XTAL2
VIH1
0.7 VCC
VCC + 0.5
V
–
Input high voltage to RESET and
HWPD
VIH2
0.6 VCC
VCC + 0.5
V
–
Input high voltage (CMOS)
(ports 0 - 9)
VIHC
0.7 VCC
VCC + 0.5
V
–
CMOS input hysteresis
(ports 1, 3 to 9)
VIHYS
0.1
–
V
–
Semiconductor Group
11-1
1997-10-01
Device Specifications
C509-L
Parameter
Symbol
Limit Values
min.
max.
Unit
Test Condition
Output low voltage
(ports 1, 2, 3, 4, 5, 6, 9)
VOL
–
0.45
V
IOL = 1.6 mA 1)
Output low voltage
(ports ALE, PSEN/RDF, RO)
VOL1
–
0.45
V
IOL = 3.2mA 1)
Output high voltage
(ports 1, 2, 3, 4, 5, 6, 9)
VOH
2.4
0.9 VCC
–
–
V
V
IOH = –80 µA
IOH = –10 µA
Output high voltage
(port 0 in external bus mode, ALE,
PSEN/RDF, RO)
VOH1
2.4
0.9 VCC
–
–
V
V
IOH = –800 µA
IOH = –80 µA 2)
Output high voltage (CMOS)
(ports 1, 2, 3, 4, 5, 6, 9)
VOHC
0.9 VCC
–
V
IOH = –800 µA
Logic input low current
(ports 1, 2, 3, 4, 5, 6, 9)
IIL
– 10
– 70
µA
VIN = 0.45 V
Logical 1-to-0 transition current
(ports 1, 2, 3, 4, 5, 6, 9)
ITL
– 65
– 650
µA
VIN = 2 V
ILI
–
nA
0.45 < VIN < VCC
nA
0.45 < VIN < VCC
TA > 100 oC
Input leakage current
(port 0, 7, 8, HWPD)
6)
(port 0 in CMOS)
± 100
± 150
Input leakage current
(EA, PRGEN)
(ports 1, 2, 3, 4, 5, 6, 9 in CMOS)
ILIC
–
±1
µA
0.45 < VIN < VCC
Input low current to RESET for reset
ILI2
– 10
–100
µA
VIN = 0.45 V
Input low current (XTAL2)
ILI3
–
– 15
µA
VIN = 0.45 V
Input low current (PE/SWD, OWE)
ILI4
–
– 20
µA
VIN = 0.45 V
Pin capacitance
C IO
–
10
pF
fC = 1 MHz
TA = 25 oC
Overload current
IOV
–
±5
mA
Semiconductor Group
11-2
7) 8)
1997-10-01
Device Specifications
C509-L
Power Supply Current
Parameter
Symbol
Limit Values
typ. 9)
max. 10)
Unit Test Condition
Active mode
12 MHz
16 MHz
ICC
ICC
31
41
37
50
mA
mA
4)
Idle mode
12 MHz
16 MHz
ICC
ICC
19
24
23
31
mA
mA
5)
IPD
30
50
µA
VCC = 2…5.5 V 3)
Power-down mode
Notes :
1) Capacitive loading on ports 0 and 2 may cause spurious noise pulses to be superimposed on the VOL of ALE
and port 1, 3, 4, 5, 6, and 9. The noise is due to external bus capacitance discharging into the port 0 and port
2 pins when these pins make 1-to-0 transitions during bus operation. In the worst case (capacitive loading
> 100 pF), the noise pulse on ALE line may exceed 0.8 V. In such cases it may be desirable to qualify ALE
with a schmitt-trigger, or use an address latch with a schmitt-trigger strobe input.
2) Capacitive loading on ports 0 and 2 may cause the VOH on ALE and PSEN/RDF to momentarily fall below the
0.9 VCC specification when the address lines are stabilizing.
3) IPD (power down mode) is measured under following conditions:
EA = RESET = VCC; Port0 = Port7 = Port8 = VCC; XTAL1 = N.C.; XTAL2 = VSS; PE/SWD = OWE = VSS;
HWDP = VCC; VAREF = VCC; VAGND = VSS; all other pins are disconnected.
Hardware power down mode current (IPD) is measured with OWE =VCC or VSS.
4) ICC (active mode) is measured with:
XTAL2 driven with tR/tF = 5 ns , VIL = VSS + 0.5 V, VIH = VCC – 0.5 V; XTAL1 = N.C.; EA = PE/SWD= VCC ;
Port0 = Port7 = Port8 = VCC ; HWPD = VCC ; RESET = VSS; all other pins are disconnected. ICC would be
slightly higher if a crystal oscillator is used.
5) ICC (idle mode) is measured with all output pins disconnected and with all peripherals disabled;
XTAL2 driven with tR/tF = 5 ns, VIL = VSS + 0.5 V, VIH = VCC – 0.5 V; XTAL1 = N.C.; RESET = VCC;
HWPD = VCC ; Port0 = Port7 = Port8 = VCC ; EA = PE/SWD = VSS; all other pins are disconnected;
6) Input leakage current for port 0 is measured with RESET = VCC.
7) Overload conditions occur if the standard operating conditions are exeeded, ie. the voltage on any pin exceeds
the specified range (i.e. VOV > VCC + 0.5 V or VOV < VSS - 0.5 V). The supply voltage VCC and VSS must remain
within the specified limits. The absolute sum of input currents on all port pins may not exceed 50 mA.
8) Not 100% tested, guaranteed by design characterization.
9) The typical ICC values are periodically measured at TA = +25 ˚C and VCC = 5 V but not 100% tested.
10)The maximum ICC values are measured under worst case conditions (TA = 0 ˚C or -40 ˚C and VCC = 5.5 V)
Semiconductor Group
11-3
1997-10-01
Device Specifications
C509-L
ICC
[mA]
60
50
40
de
o
eM
v
ti
Ac
30
e
od
M
tive
ICC max
ICC typ
Ac
e
Idle
20
Mod
Idle
e
Mod
10
3.5
8
12
16
fOSC
[MHz]
Figure 1
ICC Diagram
Power Supply Current Calculation Formulas
Parameter
Symbol
Formula
Active mode)
ICC typ
ICC max
2.5 * fOSC + 0.6
3.1 * fOSC + 0.2
Idle mode
ICC typ
ICC max
1.4 * fOSC + 1.9
1.8 * fOSC + 1.8
Note : fosc is the oscillator frequency in MHz. ICC values are given in mA.
Semiconductor Group
11-4
1997-10-01
Device Specifications
C509-L
11.3 A/D Converter Characteristics
TA = 0 to 70 °C
for the SAB-C509
TA = – 40 to 85 °C for the SAF-C509
VCC = 5 V + 10%, – 5%; VSS = 0 V
4 V ≤ VAREF ≤ VCC+0.1 V ; VSS-0.1 V ≤ VAGND ≤ VSS+0.2 V
Parameter
Symbol
Limit Values
min.
max.
Unit
Test Condition
V
1)
Analog input voltage
VAIN
VAGND
VAREF
Sample time
tS
8 t IN
512 t IN
2)
see table below
3)
see table below
Conversion time
tADCC
48 t IN
832 t IN
Total unadjusted error
TUE
–
±2
LSB
4)
Internal resistance of reference
voltage source
RAREF
–
tADC / 250
kΩ
tADC in [ns]
Internal resistance of analog
source
RASRC
kΩ
tS in [ns] 3) 6)
ADC input capacitance
CAIN
pF
6)
5) 6)
- 0.25
tS / 500
–
- 0.25
–
50
Notes see next page.
Clock calculation table
Conversion Clock Selection
ADCL1
ADCL0
Prescaler
CCP
Sample Clock Selection
ADST1
ADST0
Prescaler
SCP
Sample Time
tS
Conversion Time
t ADCC
0
0
4
0
0
1
1
0
1
0
1
2
8 x tIN
16 x tIN
32 x tIN
64 x tIN
48 x tIN
56 x tIN
72 x tIN
104 x tIN
0
1
8
0
0
1
1
0
1
0
1
4
16 x tIN
32 x tIN
64 x tIN
128 x tIN
96 x tIN
112 x tIN
144 x tIN
208 x tIN
1
0
16
0
0
1
1
0
1
0
1
8
32 x tIN
64 x tIN
128 x tIN
256 x tIN
192 x tIN
224 x tIN
288 x tIN
416 x tIN
1
1
32
0
0
1
1
0
1
0
1
16
64 x tIN
128 x tIN
256 x tIN
512 x tIN
384 x tIN
448 x tIN
576 x tIN
832 x tIN
Further timing conditions : t ADC min = 500 ns = CCP x CLP
tIN = 1 / fOSC = CLP
tSC = t ADC x SCP
Semiconductor Group
11-5
1997-10-01
Device Specifications
C509-L
Notes:
1) VAIN may exeed VAGND or VAREF up to the absolute maximum ratings. However, the conversion result in
these cases will be X000H or X3FFH, respectively.
2) During the sample time the input capacitance CAIN can be charged/discharged by the external source. The
internal resistance of the analog source must allow the capacitance to reach their final voltage level within tS.
After the end of the sample time tS, changes of the analog input voltage have no effect on the conversion
result.
3) This parameter includes the sample time tS, the time for determining the digital result and the time for the
calibration. Values for the conversion clock fADC depend on programming and can be taken from the table
below.
4) TUE is tested at VAREF = 5.0 V, VAGND = 0 V, VCC = 4.9 V. It is guaranteed by design characterization for all
other voltages within the defined voltage range.
If an overload condition occurs on maximum 2 not selected analog input pins and the absolute sum of input
overload currents on all analog input pins does not exceed 10 mA, an additional conversion error of 1/2 LSB
is permissible.
5) During the conversion the ADC’s capacitance must be repeatedly charged or discharged. The internal
resistance of the reference source must allow the capacitance to reach their final voltage level within the
indicated time. The maximum internal resistance results from the programmed conversion timing.
6) Not 100% tested, but guaranteed by design characterization.
Semiconductor Group
11-6
1997-10-01
Device Specifications
C509-L
11.4 AC Characteristics
VCC = 5 V + 10%, – 5%; VSS = 0 V
TA = 0 to 70 °C
for the SAB-C509
TA = – 40 to 85 °C for the SAF-C509
(CL for port 0, ALE and PSEN outputs = 100 pF; CL for all other outputs = 80 pF)
Program Memory Characteristics
Parameter
Symbol
Limit Values
16-MHz clock
Duty Cycle
0.45 to 0.55
Unit
Variable Clock
1/CLP = 3.5 MHz to
16 MHz
min.
max.
min.
max.
ALE pulse width
tLHLL
48
–
CLP-15
–
ns
Address setup to ALE
tAVLL
10
–
TCLHmin-15
–
ns
Address hold after ALE
tLLAX
10
–
TCLHmin-15
–
ns
Address to valid instruction in
tLLIV
–
75
–
2 CLP-50
ns
ALE to PSEN/RDF
tLLPL
10
–
TCLLmin-15
–
ns
PSEN/RDF pulse width
tPLPH
73
–
CLP+
TCLHmin-15
–
ns
PSEN/RDF to valid instruction in
tPLIV
–
38
–
CLP+
TCLHmin-50
ns
Input instruction hold after PSEN/
RDF
tPXIX
0
–
0
–
ns
Input instruction float after PSEN/
RDF
tPXIZ *)
–
15
–
TCLLmin-10
ns
Address valid after PSEN/RDF
tPXAV *)
20
–
TCLLmin-5
–
ns
Address to valid instruction in
tAVIV
–
95
–
2 CLP+
TCLHmin-55
ns
Address float to PSEN/RDF
tAZPL
-5
-5
–
ns
*)
Interfacing the C509-L to devices with float times up to 20 ns is permissible. This limited bus contention will
not cause any damage to port 0 drivers.
Semiconductor Group
11-7
1997-10-01
Device Specifications
C509-L
External Data Memory Characteristics
Parameter
Symbol
Limit Values
16-MHz clock
Duty Cycle
0.45 to 0.55
Unit
Variable Clock
1/CLP= 3.5 MHz to
16 MHz
min.
max.
min.
max.
RD pulse width
tRLRH
158
–
3 CLP-30
–
ns
WR pulse width
tWLWH
158
–
3 CLP-30
–
ns
Address hold after ALE
tLLAX2
48
–
CLP -15
–
ns
RD to valid data in
tRLDV
–
100
–
2 CLP+
TCLHmin-50
ns
Data hold after RD
tRHDX
0
0
–
ns
Data float after RD
tRHDZ
–
51
–
CLP-12
ns
ALE to valid data in
tLLDV
–
200
–
4 CLP-50
ns
Address to valid data in
tAVDV
–
200
–
4 CLP+
TCLHmin-75
ns
ALE to WR or RD
tLLWL
73
103
CLP+
TCLLmin-15
CLP+
ns
TCLLmin+15
Address valid to WR
tAVWL
95
–
2 CLP-30
–
WR or RD high to ALE high
tWHLH
10
40
TCLHmin-15
TCLHmin+15 ns
Data valid to WR transition
tQVWX
5
–
TCLLmin-20
–
ns
Data setup before WR
tQVWH
163
–
3 CLP+
TCLLmin-50
–
ns
Data hold after WR
tWHQX
5
–
TCLHmin-20
–
ns
Address float after RD
tRLAZ
–
0
–
0
ns
Semiconductor Group
11-8
ns
1997-10-01
Device Specifications
C509-L
External Clock Drive XTAL2
Parameter
Symbol
CPU Clock = 16 MHz
Duty cycle 0.45 to 0.55
Variable CPU Clock
1/CLP = 3.5 to 16 MHz
min.
max.
min.
max.
Unit
Oscillator period
CLP
62.5
62.5
62.5
285
ns
High time
TCLH
25
–
25
CLP-TCLL
ns
Low time
TCLL
25
–
25
CLP-TCLH
ns
Rise time
tR
–
10
–
10
ns
Fall time
tF
–
10
–
10
ns
Oscillator duty cycle
DC
0.45
0.55
25 / CLP
1 - 25 / CLP
–
Clock cycle
TCL
25
37.5
CLP * DCmin
CLP * DCmax ns
Note: The 16 MHz values in the tables are given as an example for a typical duty cycle variation of
the oscillator clock from 0.45 to 0.55.
Semiconductor Group
11-9
1997-10-01
Device Specifications
C509-L
t LHLL
ALE
t AVLL
t PLPH
t LLPL
t
LLIV
t PLIV
PSEN
t AZPL
t PXAV
t LLAX
t PXIZ
t PXIX
Port 0
A0 - A7
Instr.IN
A0 - A7
t AVIV
Port 2
A8 - A15
A8 - A15
MCT00096
Program Memory Read Cycle
t WHLH
ALE
PSEN
t LLDV
t LLWL
t RLRH
RD
t RLDV
t AVLL
t RHDZ
t LLAX2
t RLAZ
Port 0
A0 - A7 from
Ri or DPL
t RHDX
Data IN
A0 - A7
from PCL
Instr.
IN
t AVWL
t AVDV
Port 2
P2.0 - P2.7 or A8 - A15 from DPH
A8 - A15 from PCH
MCT00097
Data Memory Read Cycle
Semiconductor Group
11-10
1997-10-01
Device Specifications
C509-L
t WHLH
ALE
PSEN
t LLWL
t WLWH
WR
t QVWX
t AVLL
t WHQX
t LLAX2
Port 0
A0 - A7 from
Ri or DPL
t QVWH
Data OUT
A0 - A7
from PCL
Instr.IN
t AVWL
Port 2
P2.0 - P2.7 or A8 - A15 from DPH
A8 - A15 from PCH
MCT00098
Data Memory Write Cycle
External Clock Drive Drive XTAL2
Semiconductor Group
11-11
1997-10-01
Device Specifications
C509-L
VCC -0.5 V
0.2 VCC+0.9
Test Points
0.2 VCC -0.1
0.45 V
MCT00039
AC Inputs during testing are driven at VCC - 0.5 V for a logic ’1’ and 0.45 V for a logic ’0’.
Timing measurements are made at VIHmin for a logic ’1’ and VILmax for a logic ’0’.
AC Testing: Input, Output Waveforms
VOH -0.1 V
VLoad +0.1 V
Timing Reference
Points
VLoad
VLoad -0.1 V
VOL +0.1 V
MCT00038
For timing purposes a port pin is no longer floating when a 100 mV change from load voltage
occurs and begins to float when a 100 mV change from the loaded VOH/VOL level occurs.
IOL/IOH ≥ ± 20 mA
AC Testing: Float Waveforms
Recommended Oscillator Circuits for Crystal Oscillators up to 16 MHz
Semiconductor Group
11-12
1997-10-01
Device Specifications
C509-L
Package Outlines
GPM05623
P-MQFP-100-2
(Plastic Metric Quad Flat Package)
Sorts of Packing
Package outlines for tubes, trays etc. are contained in our
Data Book “Package Information”.
SMD = Surface Mounted Device
Semiconductor Group
11-13
Dimensions in mm
1997-10-01
Index
C509-L
12
Bootstrap loader . . . . . . . . . . . . . . . . . 10-1
Code reference addresses . . . . . . 10-32
Description of the subroutines . . . 10-29
General functions . . . . . . . . . . . . . . 10-1
General Interface to the PC . . . . . . 10-2
The three phases . . . . . . . . . . . . . . 10-2
Phase I . . . . . . . . . . . . . . . . . . . . 10-3
Checksum calculation . . . . . . . . 10-7
Flowchart . . . . . . . . . . . . . . . . . 10-6
Phase II . . . . . . . . . . . . . . . . . . . . 10-8
Automatic synch. procedure . . . 10-9
Synchronization MCU-Host . . . 10-8
Phase III . . . . . . . . . . . . . . . . . . 10-13
Block transfer protocol . . . . . . 10-13
Flowchart . . . . . . . . . . . . . . . . 10-18
Operating mode 0 . . . . . . . . . . 10-19
Operating mode 1 . . . . . . . . . . 10-23
Operating mode 2 . . . . . . . . . . 10-24
Operating mode 3 . . . . . . . . . . 10-27
Operating mode selection . . . . 10-17
BSY . . . . . . . . . . . . . . . . . . . . 3-25, 6-108
Index
Note: Bold page numbers refer to the main definition
part of SFRs or SFR bits.
A
A/D converter . . . . . . . . . . . 6-104 to 6-118
Adjustment of the sample time . . . 6-116
Analog source impedance limits . . 6-117
Block diagram . . . . . . . . . . . . . . . . 6-105
Calibration mechanisms . . . . . . . . 6-118
Clock selection . . . . . . . . . . . . . . . 6-111
Conversion time calculation 6-112, 6-115
Conversion timing . . . . . . . . . . . . . 6-112
General operation . . . . . . . . . . . . . 6-104
Registers . . . . . . . . . . . . . 6-107 to 6-110
System clock relationship . . . . . . . 6-114
A/D converter characteristics . 11-5 to 11-6
Absolute maximum ratings . . . . . . . . . 11-1
AC . . . . . . . . . . . . . . . . . . . . . . . . 2-4, 3-25
AC characteristics . . . . . . . . . 11-7 to 11-11
Data memory read cycle . . . . . . . . 11-10
Data memory write cycle . . . . . . . . 11-11
External clock cycle . . . . . . . . . . . . 11-11
Program memory read cycle . . . . . 11-10
AC Testing
Float waveforms . . . . . . . . . . . . . . 11-12
Input/output waveforms . . . . . . . . . 11-12
ACC . . . . . . . . . . . . . . . . . . 2-3, 3-19, 3-26
ADCL0 . . . . . . . . . . . . . . . . . . 3-26, 6-109
ADCL1 . . . . . . . . . . . . . . . . . . 3-26, 6-109
ADCON0 3-19, 3-21, 3-25, 5-8, 6-85, 6-108
ADCON1 . . . . . . . . . . . . . 3-19, 3-26, 6-108
ADDATH . . . . . . . . . . . . . 3-19, 3-25, 6-107
ADDATL . . . . . . . . . . . . . 3-19, 3-26, 6-107
ADEX . . . . . . . . . . . . . . . . . . . 3-25, 6-108
ADM . . . . . . . . . . . . . . . . . . . . 3-25, 6-108
ADST . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
ADST0 . . . . . . . . . . . . . . . . . . 3-26, 6-109
ADST1 . . . . . . . . . . . . . . . . . . 3-26, 6-109
ALE signal . . . . . . . . . . . . . . . . . . . . . . . 4-4
ARCON . . . . . . . . . . . . . . . 3-22, 3-27, 6-76
C
B
B . . . . . . . . . . . . . . . . . . . . . 2-4, 3-19, 3-27
Basic CPU timing . . . . . . . . . . . . . . . . . 2-5
BD . . . . . . . . . . . . . . . . . . . . . . . 3-25, 6-85
Block diagram . . . . . . . . . . . . . . . . . . . . 2-2
Semiconductor Group
12-1
C/T . . . . . . . . . . . . . . . . . . . . . . 3-23, 6-21
CAFR . . . . . . . . . . . . . . . . 3-21, 3-27, 6-68
CC10 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC11 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC12 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC13 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC14 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC15 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC16 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC17 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CC1EN . . . . . . . . . . . . . . . 3-20, 3-27, 6-66
CC1H0 . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CC1H1 . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CC1H2 . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CC1H3 . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CC1H4 . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CC1H5 . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CC1H6 . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
CC1H7 . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
CC1L0 . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CC1L1 . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CC1L2 . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CC1L3 . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CC1L4 . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CC1L5 . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
1997-10-01
Index
C509-L
CMH7 . . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
CML0 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CML1 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CML2 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CML3 . . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CML4 . . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CML5 . . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CML6 . . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
CML7 . . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
CMSEL . . . . . . . . . . . . . . . 3-20, 3-27, 6-59
COCAH0 . . . . . . . . . . . . . . . . . 3-24, 6-51
COCAH1 . . . . . . . . . . . . . . . . . 3-24, 6-51
COCAH2 . . . . . . . . . . . . . . . . . 3-24, 6-51
COCAH3 . . . . . . . . . . . . . . . . . 3-24, 6-50
COCAH4 . . . . . . . . . . . . . 3-25, 6-57, 6-58
COCAL0 . . . . . . . . . . . . . . . . . . 3-24, 6-51
COCAL1 . . . . . . . . . . . . . . . . . . 3-24, 6-51
COCAL2 . . . . . . . . . . . . . . . . . . 3-24, 6-51
COCAL3 . . . . . . . . . . . . . . . . . . 3-24, 6-50
COCAL4 . . . . . . . . . . . . . . 3-25, 6-57, 6-58
COCOEN0 . . . . . . . . . . . . 3-25, 6-57, 6-58
COCOEN1 . . . . . . . . . . . . 3-25, 6-57, 6-58
COCON0 . . . . . . . . . . . . . . . . . 3-25, 6-57
COCON1 . . . . . . . . . . . . . . . . . 3-25, 6-57
COCON2 . . . . . . . . . . . . . . . . . 3-25, 6-57
COMCLRH . . . . . . . . . . . . . . . . 3-21, 3-24
COMCLRL . . . . . . . . . . . . . . . . 3-21, 3-24
COMO . . . . . . . . . . . . . . . . . . . 3-25, 6-57
Compare/capture unit . . . . . . . . . . . . . 6-28
Alternate fucntions of pins . . . . . . . 6-30
Block diagram . . . . . . . . . . . . . . . . . 6-29
Capture functions
Timer 2 with CRC, CC1 to CC3
. . . . . . . . . . . . . . . . . . . . 6-53 to 6-54
Compare functions . . . . . . . . . . . . . 6-44
CMx with compare timer . 6-60 to 6-62
CMx with timer 2 . . . . . . . . . . . . . 6-63
Compare mode 0 . . . . . . . 6-45, 6-48
Compare mode 1 . . . . . . . . . . . . 6-47
Concurrent compare with CC4
. . . . . . . . . . . . . . . . . . . . 6-55 to 6-58
Modulation range in compare mode 0
. . . . . . . . . . . . . . . . . . . . 6-69 to 6-70
Timer 2 in compare mode 2 . . . . 6-64
Timer 2 with CRC, CC1 to CC3
. . . . . . . . . . . . . . . . . . . . 6-50 to 6-52
Timer-/compare configurations . . 6-49
CC1L6 . . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
CC1L7 . . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
CC4EN . . . . . . . . . . . . . . . 3-20, 3-25, 6-57
CCEN . . . . . . . . . . . . . . . . 3-20, 3-24, 6-50
CCH1 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCH2 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCH3 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCH4 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCL1 . . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCL2 . . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCL3 . . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCL4 . . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CCM0 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CCM1 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CCM2 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CCM3 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CCM4 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CCM5 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CCM6 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
CCM7 . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
Chipmode selection . . . . . . . . . . . . . . 3-12
CLK . . . . . . . . . . . . . . . . . . . . . . . 3-25, 5-8
CLK0 . . . . . . . . . . . . . . . . . . . . . 3-26, 6-40
CLK1 . . . . . . . . . . . . . . . . . . . . . 3-26, 6-40
CLK10 . . . . . . . . . . . . . . . . . . . . 3-24, 6-40
CLK11 . . . . . . . . . . . . . . . . . . . . 3-24, 6-40
CLK12 . . . . . . . . . . . . . . . . . . . . 3-24, 6-40
CLK2 . . . . . . . . . . . . . . . . . . . . . 3-26, 6-40
CLKOUT . . . . . . . . . . . . . . . . . . . 3-23, 5-8
CLKP . . . . . . . . . . . . . . . . . . . . . . 3-24, 5-8
CLRMSK . . . . . . . . . . . . . . 3-21, 3-24, 6-64
CM0 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CM1 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CM2 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CM3 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CM4 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CM5 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CM6 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CM7 . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
CMEN . . . . . . . . . . . . . . . . 3-20, 3-27, 6-59
CMH0 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CMH1 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CMH2 . . . . . . . . . . . . . . . . 3-20, 3-25, 6-31
CMH3 . . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CMH4 . . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CMH5 . . . . . . . . . . . . . . . . 3-20, 3-26, 6-31
CMH6 . . . . . . . . . . . . . . . . 3-20, 3-27, 6-31
Semiconductor Group
12-
1997-10-01
Index
C509-L
Using CM0 to CM7 . . . . . 6-59 to 6-63
Using interrupts . . . . . . . . 6-71 to 6-74
Compare timer 1 operation . 6-65 to 6-68
Capture function . . . . . . . . . . . . . 6-68
Compare function . . . . . . . . . . . . 6-66
Table of CCU SFRs . . . . . . . . . . . . . 6-31
COMSETH . . . . . . . . . . . . . . . . 3-21, 3-24
COMSETL . . . . . . . . . . . . . . . . . 3-21, 3-23
CPU
Accumulator . . . . . . . . . . . . . . . . . . . 2-3
B register . . . . . . . . . . . . . . . . . . . . . . 2-4
Basic timing . . . . . . . . . . . . . . . . . . . . 2-5
Fetch/execute diagram . . . . . . . . . . . 2-6
Functionality . . . . . . . . . . . . . . . . . . . 2-3
Stack pointer . . . . . . . . . . . . . . . . . . . 2-4
CRCH . . . . . . . . . . . . . . . . 3-21, 3-25, 6-35
CRCL . . . . . . . . . . . . . . . . 3-21, 3-25, 6-35
CT1CON . . . . 3-19, 3-21, 3-24, 6-39, 7-16
CT1F . . . . . . . . . . . . . . . . . 3-24, 6-40, 7-16
CT1P . . . . . . . . . . . . . . . . . . . . . 3-24, 6-40
CT1RELH . . . . . . . . . . . . . 3-21, 3-26, 6-41
CT1RELL . . . . . . . . . . . . . 3-21, 3-26, 6-41
CTCON . 3-19, 3-21, 3-26, 6-33, 6-39, 7-16
CTF . . . . . . . . . . . . . . . . . . 3-26, 6-39, 7-16
CTP . . . . . . . . . . . . . . . . . . . . . . 3-26, 6-40
CTRELH . . . . . . . . . . . . . . 3-21, 3-26, 6-41
CTRELL . . . . . . . . . . . . . . 3-21, 3-26, 6-41
CY . . . . . . . . . . . . . . . . . . . . . . . . 2-4, 3-25
DPH . . . . . . . . . . . . . . . . . . . . . 3-19, 3-23
DPL . . . . . . . . . . . . . . . . . . . . . 3-19, 3-23
DPSEL . . . . . . . . . . . . . . . . 3-19, 3-23, 4-6
E
D
Data memory . . . . . . . . . . . . . . . . . . . . 3-2
Datapointers . . . . . . . . . . . . . . . . 4-6 to 4-9
Access mechanism . . . . . . . . . . . . . . 4-7
Basic operation . . . . . . . . . . . . . . . . . 4-6
Example using multiple DPTRs . . . . . 4-9
Example using one DPTR . . . . . . . . . 4-8
Select register DPSEL . . . . . . . . . . . . 4-6
DC characteristics . . . . . . . . . . 11-1 to 11-6
Device Characteristics . . . . . 11-1 to 11-13
DIR0 . . . . . . . . . . . . . . . . . . 3-22, 3-23, 6-4
DIR1 . . . . . . . . . . . . . . . . . . 3-22, 3-23, 6-4
DIR2 . . . . . . . . . . . . . . . . . . 3-22, 3-23, 6-4
DIR3 . . . . . . . . . . . . . . . . . . 3-22, 3-24, 6-4
DIR4 . . . . . . . . . . . . . . . . . . 3-22, 3-26, 6-4
DIR5 . . . . . . . . . . . . . . . . . . 3-22, 3-27, 6-4
DIR6 . . . . . . . . . . . . . . . . . . 3-22, 3-27, 6-4
DIR9 . . . . . . . . . . . . . . . . . . 3-22, 3-27, 6-4
Direction registers . . . . . . . . . . . . . . . . . 6-4
Semiconductor Group
12-3
EA0 . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
EA1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
EADC . . . . . . . . . . . . . . . . 3-24, 6-110, 7-7
EAL . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-6
ECC1 . . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
ECMP . . . . . . . . . . . . . . . . . 3-23, 6-73, 7-8
ECR . . . . . . . . . . . . . . . . . . 3-23, 6-73, 7-8
ECS . . . . . . . . . . . . . . . . . . 3-23, 6-73, 7-8
ECT . . . . . . . . . . . . . . . . . . 3-23, 6-73, 7-8
ECT1 . . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC1 . . . . . . . . . . . . 3-19, 3-24, 6-73, 7-9
EICC10 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC11 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC12 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC13 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC14 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC15 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC16 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
EICC17 . . . . . . . . . . . . . . . . 3-24, 6-73, 7-9
Emulation concept . . . . . . . . . . . . . . . . 4-5
ES0 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-6
ES1 . . . . . . . . . . . . . . . . . . . . . . . 3-23, 7-8
ESWC . . . . . . . . . . . . . . . . 3-10, 3-13, 3-24
ET0 . . . . . . . . . . . . . . . . . . . 3-24, 6-20, 7-6
ET1 . . . . . . . . . . . . . . . . . . . 3-24, 6-20, 7-6
ET2 . . . . . . . . . . . . . . . . . . . 3-24, 6-34, 7-6
EX0 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-6
EX1 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-6
EX2 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-7
EX3 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-7
EX4 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-7
EX5 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-7
EX6 . . . . . . . . . . . . . . . . . . . . . . . 3-24, 7-7
Execution of instructions . . . . . . . 2-5, 2-6
EXEN2 . . . . . . . . . . . . . . . . 3-24, 6-35, 7-7
EXF2 . . . . . . . . . . . . . . . . 3-24, 6-35, 7-14
External bus interface . . . . . . . . . . . . . . 4-1
ALE signal . . . . . . . . . . . . . . . . . . . . . 4-4
Overlapping of data/program memory 4-2
Program memory access . . . . . . . . . 4-2
Program/data memory timing . . . . . . 4-3
PSEN signal . . . . . . . . . . . . . . . . . . . 4-2
Role of P0 and P2 . . . . . . . . . . . . . . . 4-1
1997-10-01
Index
C509-L
IDLS . . . . . . . . . . . . . . . . . . . . . . 3-23, 9-3
IE0 . . . . . . . . . . . . . . . . . . . . . . 3-23, 7-11
IE1 . . . . . . . . . . . . . . . . . . . . . . 3-23, 7-11
IEN0 3-19, 3-21, 3-24, 6-20, 6-33, 7-6, 8-3
IEN1 3-19, 3-21, 3-24, 6-33, 6-110, 7-7, 8-3
IEN2 . . . . . . . . . . . . . 3-19, 3-23, 6-73, 7-8
IEN3 . . . . . . . . . . . . . 3-19, 3-24, 6-73, 7-9
IEX2 . . . . . . . . . . . . . . . . . . . . . 3-24, 7-14
IEX3 . . . . . . . . . . . . . . . . . . . . . 3-24, 7-14
IEX4 . . . . . . . . . . . . . . . . . . . . . 3-24, 7-14
IEX5 . . . . . . . . . . . . . . . . . . . . . 3-24, 7-14
IEX6 . . . . . . . . . . . . . . . . . . . . . 3-24, 7-14
INT0 . . . . . . . . . . . . . . . . . . . . . 3-24, 7-21
INT1 . . . . . . . . . . . . . . . . . . . . . 3-24, 7-21
INT2 . . . . . . . . . . . . . . . . . . . . . 3-23, 7-21
INT3 . . . . . . . . . . . . . . . . . . . . . 3-23, 7-21
INT4 . . . . . . . . . . . . . . . . . . . . . 3-23, 7-21
INT5 . . . . . . . . . . . . . . . . . . . . . 3-23, 7-21
INT6 . . . . . . . . . . . . . . . . . . . . . 3-23, 7-21
Interrupts . . . . . . . . . . . . . . . . . . . . . . . 7-1
Block diagram . . . . . . . . . . . . . 7-2 to 7-5
Enable registers . . . . . . . . . . . 7-6 to 7-9
External interrupts . . . . . . . . . . . . . . 7-21
Handling procedure . . . . . . . . . . . . 7-19
Priority registers . . . . . . . . . . . . . . . 7-10
Priority within level structure 7-17 to 7-18
Request flags . . . . . . . . . . . 7-11 to 7-16
Response time . . . . . . . . . . . . . . . . 7-22
Sources and vector addresses . . . . 7-20
IP0 . . . . . . 3-19, 3-21, 3-24, 7-10, 8-3, 8-6
IP1 . . . . . 3-17, 3-19, 3-21, 3-24, 6-4, 7-10
IRCON0 . . . . 3-19, 3-24, 6-33, 6-110, 7-14
IRCON1 . . . . . . . . . 3-19, 3-25, 6-74, 7-15
IRCON2 . . . . . . . . . 3-19, 3-24, 6-74, 7-15
IT0 . . . . . . . . . . . . . . . . . . . . . . 3-23, 7-11
IT1 . . . . . . . . . . . . . . . . . . . . . . 3-23, 7-11
External memory
Bootstrap mode . . . . . . . . . . . . . . . . . 3-7
Chipmode control signals . . . . . . . . 3-14
Chipmode selection . . . . . . . . 3-12, 3-15
General interface . . . . . . . . . . . . . . . . 3-4
Normal mode . . . . . . . . . . . . . . . . . . . 3-5
Programming mode . . . . . . . . . . . . . . 3-8
Software unlock sequence . . . . . . . 3-13
XRAM mode . . . . . . . . . . . . . . . . . . . 3-6
F
F0 . . . . . . . . . . . . . . . . . . . . . . . . 2-4, 3-25
F1 . . . . . . . . . . . . . . . . . . . . . . . . 2-4, 3-25
Fast power-on reset . . . . . . . . . . . . . . . 5-4
Features . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Functional unita . . . . . . . . . . . . . . . . . . . 1-1
Fundamental structure . . . . . . . . . . . . . 2-1
G
GATE . . . . . . . . . . . . . . . . . . . . 3-23, 6-21
General purpose registers . . . . . . . . . . 3-2
GF0 . . . . . . . . . . . . . . . . . . . . . . . 3-23, 9-3
GF1 . . . . . . . . . . . . . . . . . . . . . . . 3-23, 9-3
I
I/O ports . . . . . . . . . . . . . . . . . . 6-1 to 6-18
I2FR . . . . . . . . . . . . . . . . . . . . . 3-25, 7-13
I3FR . . . . . . . . . . . . . . . . . . . . . 3-25, 7-13
IADC . . . . . . . . . . . . . . . . 3-24, 6-110, 7-14
ICC10 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICC11 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICC12 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICC13 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICC14 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICC15 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICC16 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICC17 . . . . . . . . . . . . . . . . 3-24, 6-74, 7-15
ICMP0 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICMP1 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICMP2 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICMP3 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICMP4 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICMP5 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICMP6 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICMP7 . . . . . . . . . . . . . . . . 3-25, 6-74, 7-15
ICR . . . . . . . . . . . . . . . . . . 3-26, 6-39, 7-16
ICS . . . . . . . . . . . . . . . . . . 3-26, 6-39, 7-16
IDLE . . . . . . . . . . . . . . . . . . . . . . 3-23, 9-3
Idle mode . . . . . . . . . . . . . . . . . . 9-4 to 9-5
Semiconductor Group
L
Logic symbol . . . . . . . . . . . . . . . . . . . . 1-3
M
M0 . . . . . . . . . . . . . . . . . . . . . . 3-23, 6-21
M1 . . . . . . . . . . . . . . . . . . . . . . 3-23, 6-21
MD0 . . . . . . . . . . . . . . . . . 3-22, 3-26, 6-75
MD1 . . . . . . . . . . . . . . . . . 3-22, 3-26, 6-75
MD2 . . . . . . . . . . . . . . . . . 3-22, 3-26, 6-75
MD3 . . . . . . . . . . . . . . . . . 3-22, 3-26, 6-75
MD4 . . . . . . . . . . . . . . . . . 3-22, 3-26, 6-75
MD5 . . . . . . . . . . . . . . . . . 3-22, 3-27, 6-75
12-
1997-10-01
Index
C509-L
MDEF . . . . . . . . . . . . . . . . . . . . 3-27, 6-76
MDOV . . . . . . . . . . . . . . . . . . . . 3-27, 6-76
Memory map . . . . . . . . . . . . . . . . . . . . . 3-1
Memory organization . . . . . . . . . . . . . . 3-1
Bootstrap mode . . . . . . . . . . . . . . . . . 3-7
Chipmodes . . . . . . . . . . . . . . . . . . . . 3-3
Data memory . . . . . . . . . . . . . . . . . . . 3-2
General purpose registers . . . . . . . . . 3-2
Memory map . . . . . . . . . . . . . . . . . . . 3-1
Normal mode . . . . . . . . . . . . . . . . . . . 3-5
Program memory . . . . . . . . . . . . . . . . 3-2
Programming mode . . . . . . . . . . . . . . 3-8
SYSCON1 register . . . . . . . 3-10 to 3-11
XRAM mode . . . . . . . . . . . . . . . . . . . 3-6
Multiplication/division unit . . . . 6-75 to 6-81
Error flag . . . . . . . . . . . . . . . . . . . . . 6-80
Multiplication and division . . . . . . . . 6-78
Normalize and shift . . . . . . . 6-79 to 6-80
Operation . . . . . . . . . . . . . . . . . . . . . 6-77
Overflow flag . . . . . . . . . . . . . . . . . . 6-80
Registers . . . . . . . . . . . . . . . 6-75 to 6-76
MX0 . . . . . . . . . . . . . . . . . 3-25, 3-26, 6-108
MX1 . . . . . . . . . . . . . . . . . 3-25, 3-26, 6-108
MX2 . . . . . . . . . . . . . . . . . 3-25, 3-26, 6-108
MX3 . . . . . . . . . . . . . . . . . . . . . 3-26, 6-108
O
Oscillator operation . . . . . . . . . . . 5-6 to 5-7
External clock source . . . . . . . . . . . . 5-7
On-chip oscillator circuitry . . . . . . . . . 5-7
Recommended oscillator circuit . . . . 5-6
Oscillator watchdog . . . . . . . . . . . 8-6 to 8-7
Behaviour at reset . . . . . . . . . . . . . . . 5-4
Block diagram . . . . . . . . . . . . . . . . . . 8-7
Functionality . . . . . . . . . . . . . . . . . . . 8-6
OV . . . . . . . . . . . . . . . . . . . . . . . . 2-4, 3-25
OWDS . . . . . . . . . . . . . . . . . . . . . 3-24, 8-6
P
P . . . . . . . . . . . . . . . . . . . . . . . . . 2-4, 3-25
P0 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-23
P1 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-23
P2 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-23
P3 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-24
P4 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-26
P5 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-27
P6 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-27
P7 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-26
P8 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-26
Semiconductor Group
12-5
P9 . . . . . . . . . . . . . . . . . . . . . . . 3-22, 3-27
Parallel I/O . . . . . . . . . . . . . . . . 6-1 to 6-18
PCON . . . . . . . . 3-21, 3-22, 3-23, 6-85, 9-3
PDE . . . . . . . . . . . . . . . . . . . . . . 3-23, 9-3
PDIR . . . . . . . . . . . 3-17, 3-24, 6-3, 6-4, 6-4
PDS . . . . . . . . . . . . . . . . . . . . . . 3-23, 9-3
Pin configuration . . . . . . . . . . . . . . . . . . 1-4
Pin definitions . . . . . . . . . . . . . . 1-5 to 1-12
PMOD . . . . . . . . . . . . . . . . . . . . . 3-24, 6-4
Port structure selection . . . . . . . . . . . . . 6-3
Ports . . . . . . . . . . . . . . . . . . . . . 6-1 to 6-18
Alternate functions . . . . . . . 6-14 to 6-15
Basic structure . . . . . . . . . . . . . . . . . 6-2
Bidirectional (CMOS) port structure
. . . . . . . . . . . . . . . . . . . . 6-10 to 6-13
Hardware power down mode . . . 6-13
Input mode . . . . . . . . . . . . . . . . . 6-10
Output mode . . . . . . . . . . 6-11 to 6-12
Port loading and interfacing . . . . . . 6-17
Port timing . . . . . . . . . . . . . . . . . . . . 6-16
Quasi-bidirectional port structure
. . . . . . . . . . . . . . . . . . . . . . 6-5 to 6-9
Basic circuitry . . . . . . . . . . . . . . . . 6-5
Output driver circuitry . . . . . . . . . . 6-6
Port 0 circuitry . . . . . . . . . . . . . . . . 6-8
Port 0/2 as address/data bus . . . . 6-9
Read-modify-write function . . . . . . . 6-17
Selection of port structure . . . . . . . . . 6-3
Types and structures . . . . . . . . . . . . 6-1
Power saving modes . . . . . . . . . . . . . . 9-1
Hardware enable . . . . . . . . . . . . . . . 9-2
Hardware power down mode . . . . . . 9-8
Reset timing . . . . . . . . . . . . . . . . 9-10
Status of external pins . . . . . . . . . . 9-9
Idle mode . . . . . . . . . . . . . . . . 9-4 to 9-5
Status of external pins . . . . . . . . . . 9-5
Register PCON . . . . . . . . . . . . . . . . . 9-3
Slow down mode . . . . . . . . . . . . . . . 9-7
Software power down mode . . . . . . . 9-6
Status of external pins . . . . . . . . . . 9-5
PRGEN0 . . . . . . . . . . . . . . . . . . 3-11, 3-24
PRGEN1 . . . . . . . . . . . . . . 3-10, 3-13, 3-24
Program memory . . . . . . . . . . . . . . . . . 3-2
PRSC 3-21, 3-22, 3-24, 6-22, 6-33, 6-85, 8-2
PSEN signal . . . . . . . . . . . . . . . . . . . . . 4-2
PSW . . . . . . . . . . . . . . 2-3, 2-4, 3-19, 3-25
1997-10-01
Index
C509-L
R
Operating modes . . . . . . . . . . . . . 6-90
Registers . . . . . . . . . . . . . . . . . . . 6-91
SETMSK . . . . . . . . . . . . . . 3-21, 3-24, 6-64
SLR . . . . . . . . . . . . . . . . . . . . . 3-27, 6-76
SM . . . . . . . . . . . . . . . . . . . . . . 3-23, 6-91
SM0 . . . . . . . . . . . . . . . . . . . . . 3-23, 6-84
SM1 . . . . . . . . . . . . . . . . . . . . . 3-23, 6-84
SM20 . . . . . . . . . . . . . . . . . . . . 3-23, 6-84
SM21 . . . . . . . . . . . . . . . . . . . . 3-23, 6-91
SMOD . . . . . . . . . . . . . . . . . . . . 3-23, 6-85
SP . . . . . . . . . . . . . . . . . . . . 2-4, 3-19, 3-23
Special Function Registers . . . . . . . . . 3-17
Access using PDIR and RMAP . . . . 3-17
Table - address ordered . . . 3-23 to 3-27
Table - functional order . . . . 3-19 to 3-22
SWAP . . . . . . . . . . . 3-11, 3-13, 3-15, 3-24
SWC . . . . . . . . . . . . . . . . . 3-10, 3-13, 3-24
SWDT . . . . . . . . . . . . . . . . . . . . . 3-24, 8-3
Switching of the SWAP bit . . . . . . . . . 3-15
SYSCON
. . . 3-17, 3-19, 3-24, 4-4, 4-10, 5-8, 6-4
SYSCON1 . . 3-10, 3-15, 3-19, 3-24, 10-23
System clock output . . . . . . . . . . 5-8 to 5-9
RB80 . . . . . . . . . . . . . . . . . . . . . 3-23, 6-84
RB81 . . . . . . . . . . . . . . . . . . . . . 3-23, 6-91
RD . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
Recommended oscillator circuits . . . 11-12
REN0 . . . . . . . . . . . . . . . . . . . . 3-23, 6-84
REN1 . . . . . . . . . . . . . . . . . . . . 3-23, 6-91
Reset
Fast power-on reset . . . . . . . . . . . . . 5-4
Power-on reset timing . . . . . . . . . . . . 5-5
Reset operation . . . . . . . . . . . . . . 5-1 to 5-6
CPU timing after reset . . . . . . . . . . . . 5-3
Hardware reset timing . . . . . . . . . . . . 5-3
Reset circuitries . . . . . . . . . . . . . . . . . 5-2
Reset output RO . . . . . . . . . . . . . . . . 5-6
RI0 . . . . . . . . . . . . . . . . . . 3-23, 6-84, 7-12
RI1 . . . . . . . . . . . . . . . . . . 3-23, 6-91, 7-12
RMAP . . . . . . . . . . . . . . . . . . . . 3-17, 3-24
RS0 . . . . . . . . . . . . . . . . . . . . 2-4, 3-2, 3-25
RS1 . . . . . . . . . . . . . . . . . . . . 2-4, 3-2, 3-25
RxD0 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-82
RxD1 . . . . . . . . . . . . . . . . . . . . . 3-27, 6-90
S
T
S0BUF . . . . . . . . . . . . . . . 3-21, 3-23, 6-84
S0CON . . . . . . . . . . 3-21, 3-23, 6-84, 7-12
S0P . . . . . . . . . . . . . . . . . . . . . . 3-24, 6-85
S0RELH . . . . . . . . . . . . . . 3-21, 3-24, 6-88
S0RELL . . . . . . . . . . . . . . . 3-21, 3-24, 6-88
S1BUF . . . . . . . . . . . . . . . 3-21, 3-23, 6-91
S1CON . . . . . . . . . . 3-21, 3-23, 6-91, 7-12
S1P . . . . . . . . . . . . . . . . . . . . . . 3-23, 6-91
S1RELH . . . . . . . . . . . . . . 3-21, 3-24, 6-93
S1RELL . . . . . . . . . . . . . . . 3-21, 3-23, 6-93
SD . . . . . . . . . . . . . . . . . . . . . . . . 3-23, 9-3
Serial interfaces
Operating mode 0 . . . . . . . . 6-94 to 6-96
Operating mode 1/mode B . 6-97 to 6-99
Operating mode 2 and 3/mode A
. . . . . . . . . . . . . . . . . . . 6-100 to 6-103
Serial interface 0 . . . . . . . . . 6-82 to 6-89
Baudrate generation . . . . 6-85 to 6-89
Multiprocessor communication . . 6-83
Operating modes . . . . . . . 6-82 to 6-83
Registers . . . . . . . . . . . . . . . . . . . 6-84
Serial interface 1 . . . . . . . . . 6-90 to 6-93
Baud rate generation . . . . 6-92 to 6-93
Multiprocessor communication . . 6-92
Semiconductor Group
T0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
T0P0 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-22
T0P1 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-22
T1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
T1P0 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-22
T1P1 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-22
T2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
T2CM . . . . . . . . . . . . . . . . . . . . 3-25, 6-50
T2CON . 3-19, 3-21, 3-25, 6-33, 6-50, 7-13
T2EX . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
T2I0 . . . . . . . . . . . . . . . . . . . . . 3-25, 6-34
T2I1 . . . . . . . . . . . . . . . . . . . . . 3-25, 6-34
T2P0 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-34
T2P1 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-34
T2PS . . . . . . . . . . . . . . . . . . . . 3-25, 6-34
T2PS1 . . . . . . . . . . . . . . . . . . . 3-26, 6-34
T2R0 . . . . . . . . . . . . . . . . . . . . . 3-25, 6-34
T2R1 . . . . . . . . . . . . . . . . . . . . . 3-25, 6-34
TB80 . . . . . . . . . . . . . . . . . . . . . 3-23, 6-84
TB81 . . . . . . . . . . . . . . . . . . . . . 3-23, 6-91
TCON . . . . . . . 3-19, 3-22, 3-23, 6-20, 7-11
TF0 . . . . . . . . . . . . . . . . . . 3-23, 6-20, 7-11
TF1 . . . . . . . . . . . . . . . . . . 3-23, 6-20, 7-11
12-
1997-10-01
Index
C509-L
TF2 . . . . . . . . . . . . . . . . . . 3-24, 6-35, 7-14
TH0 . . . . . . . . . . . . . . . . . . 3-22, 3-23, 6-23
TH1 . . . . . . . . . . . . . . . . . . 3-22, 3-23, 6-23
TH2 . . . . . . . . . . . . . . . . . . 3-21, 3-25, 6-35
TI0 . . . . . . . . . . . . . . . . . . . 3-23, 6-84, 7-12
TI1 . . . . . . . . . . . . . . . . . . . 3-23, 6-91, 7-12
Timer/counter
Compare timers . . . . . . . . . . 6-39 to 6-42
Operating modes . . . . . . . 6-42 to 6-43
Registers . . . . . . . . . . . . . 6-39 to 6-41
Timer/counter 0 and 1 . . . . . 6-19 to 6-27
Mode 0, 13-bit timer/counter . . . . 6-24
Mode 1, 16-bit timer/counter . . . . 6-25
Mode 2, 8-bit rel. timer/counter . . 6-26
Mode 3, two 8-bit timer/counter . . 6-27
Registers . . . . . . . . . . . . . 6-20 to 6-23
Timer/counter 2 . . . . . . . . . . 6-33 to 6-38
Block diagram . . . . . . . . . . . . . . . 6-36
Capture mode . . . . . . . . . 6-53 to 6-54
Compare mode . . . . . . . . 6-50 to 6-52
Concurrent compare mode 6-55 to 6-56
Event counter mode . . . . . . . . . . . 6-37
Gated timer mode . . . . . . . . . . . . 6-37
Registers . . . . . . . . . . . . . 6-33 to 6-35
Reload mode . . . . . . . . . . . . . . . . 6-37
TL0 . . . . . . . . . . . . . . . . . . 3-22, 3-23, 6-23
TL1 . . . . . . . . . . . . . . . . . . 3-22, 3-23, 6-23
TL2 . . . . . . . . . . . . . . . . . . 3-21, 3-25, 6-35
TMOD . . . . . . . . . . . . . . . . 3-22, 3-23, 6-21
TR0 . . . . . . . . . . . . . . . . . . . . . . 3-23, 6-20
TR1 . . . . . . . . . . . . . . . . . . . . . . 3-23, 6-20
TxD0 . . . . . . . . . . . . . . . . . . . . . 3-24, 6-82
TxD1 . . . . . . . . . . . . . . . . . . . . . 3-27, 6-90
WDTREL . . . . . . . . . . . . . . 3-21, 3-23, 8-2
WDTS . . . . . . . . . . . . . . . . . . . . . 3-24, 8-3
WPSEL . . . . . . . . . . . . . . . . . . . . 3-23, 8-2
WR . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
X
XMAP0 . . . . . . . . . . . . . . . . . . . 3-24, 4-10
XMAP1 . . . . . . . . . . . . . . . . . . . 3-24, 4-10
XPAGE . . . . . . . . . . . . . . . 3-19, 3-23, 4-12
XRAM operation . . . . . . . . . . . . . . . . . 4-10
Access control by SYSCON . . . . . . 4-10
Access with DPTR (16-bit) . . . . . . . 4-12
Access with R0/R1 (8-bit) . . . . . . . . 4-12
Programming example . . . . . . . . 4-15
Usage of port 2 as I/O port . . . . . 4-15
Write page address to port 2 . . . . 4-13
Write page address to XPAGE . . 4-14
XPAGE register . . . . . . . . . . . . . . 4-12
Behaviour of port 0 and 2 with MOVX
. . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Reset operation . . . . . . . . . . . . . . . 4-16
W
Watchdog timer . . . . . . . . . . . . . . 8-1 to 8-5
Behaviour in chipmodes . . . . . . . . . 3-16
Block diagram . . . . . . . . . . . . . . . . . . 8-1
Control flags . . . . . . . . . . . . . . . . . . . 8-3
Input clock selection . . . . . . . . . . . . . 8-2
Refreshing of the WDT . . . . . . . . . . . 8-5
Reset operation . . . . . . . . . . . . . . . . . 8-5
Starting of the WDT . . . . . . . . . . . . . . 8-4
Time-out periods . . . . . . . . . . . . . . . . 8-2
WDT . . . . . . . . . . . . . . . . . . . . . . 3-24, 8-3
WDTH . . . . . . . . . . . . . . . . . 3-21, 3-23, 8-1
WDTL . . . . . . . . . . . . . . . . . 3-21, 3-23, 8-1
WDTP . . . . . . . . . . . . . . . . . . . . . 3-24, 8-2
Semiconductor Group
12-7
1997-10-01