Freescale MC68HC08AZ48A Microcontroller Datasheet

MC68HC08AZ60A
MC68HC08AZ48A
Technical Data
M68HC08
Microcontrollers
Rev. 2.1
MC68HC08AZ60A/D
August 5, 2005
freescale.com
MC68HC08AZ60A
MC68HC08AZ48A
Technical Data — Rev 2.1
Freescale reserves the right to make changes without further notice to any products
herein. Freescale makes no warranty, representation or guarantee regarding the
suitability of its products for any particular purpose, nor does Freescale assume any
liability arising out of the application or use of any product or circuit, and specifically
disclaims any and all liability, including without limitation consequential or incidental
damages. "Typical" parameters which may be provided in Freescale data sheets
and/or specifications can and do vary in different applications and actual performance
may vary over time. All operating parameters, including "Typicals" must be validated
for each customer application by customer's technical experts. Freescale does not
convey any license under its patent rights nor the rights of others. Freescale products
are not designed, intended, or authorized for use as components in systems intended
for surgical implant into the body, or other applications intended to support or sustain
life, or for any other application in which the failure of the Freescale product could
create a situation where personal injury or death may occur. Should Buyer purchase or
use Freescale products for any such unintended or unauthorized application, Buyer
shall indemnify and hold Freescale and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and
reasonable attorney fees arising out of, directly or indirectly, any claim of personal
injury or death associated with such unintended or unauthorized use, even if such claim
alleges that Freescale was negligent regarding the design or manufacture of the part.
Freescale, Inc. is an Equal Opportunity/Affirmative Action Employer.
© Freescale, Inc., 2002
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List of Paragraphs
List of Paragraphs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Section 1. General Description . . . . . . . . . . . . . . . . . . . . 27
Section 2. Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Section 3. RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Section 4. ROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Section 5. EEPROM-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Section 6. EEPROM-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Section 7. Central Processor Unit (CPU) . . . . . . . . . . . . 99
Section 8. System Integration Module (SIM) . . . . . . . . 117
Section 9. Clock Generator Module (CGM) . . . . . . . . . . 139
Section 10. Mask Options. . . . . . . . . . . . . . . . . . . . . . . . 167
Section 11. Break Module. . . . . . . . . . . . . . . . . . . . . . . . 171
Section 12. Monitor ROM (MON) . . . . . . . . . . . . . . . . . . 177
Section 13. Computer Operating Properly (COP) . . . . 189
Section 14. Low Voltage Inhibit (LVI) . . . . . . . . . . . . . . 195
Section 15. External Interrupt Module (IRQ) . . . . . . . . . 201
Section 16. Serial Communications Interface (SCI) . . . 209
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Section 17. Serial Peripheral Interface (SPI). . . . . . . . . 249
Section 18. Timer Interface Module B (TIMB) . . . . . . . . 281
Section 19. Programmable Interrupt Timer (PIT) . . . . . 305
Section 20. I/O Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
Section 21. MSCAN08 Controller (MSCAN08) . . . . . . . 343
Section 22. Keyboard Module (KBD) . . . . . . . . . . . . . . . 395
Section 23. Timer Interface Module A (TIMA) . . . . . . . . 403
Section 24. Analog-to-Digital Converter (ADC-15) . . . . 433
Section 25. Electrical Specifications. . . . . . . . . . . . . . . 445
Section 26. MC68HC08AZ60A Changes . . . . . . . . . . . . 459
Section 27. MC68HC08AZ48A Memory Map . . . . . . . . . 463
Advance Information — Revision History . . . . . . . . . . 467
Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
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Table of Contents
List of Paragraphs
Table of Contents
List of Figures
List of Tables
Section 1. General Description
1.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
1.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.4
Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
1.5
Ordering Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Section 2. Memory Map
2.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
2.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.3
I/O Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.4
Additional Status and Control Registers . . . . . . . . . . . . . . . . . . 50
2.5
Vector Addresses and Priority . . . . . . . . . . . . . . . . . . . . . . . . . 52
Section 3. RAM
3.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
3.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
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3.3
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Section 4. ROM
4.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
4.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.3
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
4.4
Security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Section 5. EEPROM-1
5.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
5.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.4
EEPROM-1 Register Summary . . . . . . . . . . . . . . . . . . . . . . . .61
5.5
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
5.6
EEPROM-1 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . 69
5.7
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Section 6. EEPROM-2
6.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
6.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
6.4
EEPROM-2 Register Summary . . . . . . . . . . . . . . . . . . . . . . . .81
6.5
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
6.6
EEPROM-2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . 89
6.7
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Section 7. Central Processor Unit (CPU)
7.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99
7.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
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7.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
7.4
CPU registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
7.5
Arithmetic/Logic Unit (ALU) . . . . . . . . . . . . . . . . . . . . . . . . . . 105
7.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
7.7
CPU During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 106
7.8
Instruction Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7.9
Opcode Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Section 8. System Integration Module (SIM)
8.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
8.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
8.3
SIM Bus Clock Control and Generation . . . . . . . . . . . . . . . . . 120
8.4
Reset and System Initialization. . . . . . . . . . . . . . . . . . . . . . . . 121
8.5
SIM Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
8.6
Exception Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
8.7
Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.8
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
8.9
SIM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Section 9. Clock Generator Module (CGM)
9.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
9.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
9.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
9.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141
9.5
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
9.6
CGM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
9.7
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
9.8
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
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9.9
CGM During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 160
9.10
Acquisition/Lock Time Specifications . . . . . . . . . . . . . . . . . . . 160
Section 10. Mask Options
10.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .167
10.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
10.3
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168
Section 11. Break Module
11.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171
11.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
11.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
11.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172
11.5
Break Module Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
11.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
Section 12. Monitor ROM (MON)
12.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177
12.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
12.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
12.4
Functional description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
Section 13. Computer Operating Properly (COP)
13.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189
13.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
13.3
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190
13.4
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
13.5
COP Control Register (COPCTL) . . . . . . . . . . . . . . . . . . . . . . 193
13.6
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .193
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13.7
Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .193
13.8
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
13.9
COP Module During Break Interrupts . . . . . . . . . . . . . . . . . . . 194
Section 14. Low Voltage Inhibit (LVI)
14.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195
14.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
14.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
14.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196
14.5
LVI Status Register (LVISR) . . . . . . . . . . . . . . . . . . . . . . . . . . 198
14.6
LVI Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199
14.7
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Section 15. External Interrupt Module (IRQ)
15.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
15.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
15.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
15.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202
15.5
IRQ Module During Break Interrupts . . . . . . . . . . . . . . . . . . . 206
15.6
IRQ Status and Control Register (ISCR) . . . . . . . . . . . . . . . . 206
Section 16. Serial Communications Interface (SCI)
16.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .209
16.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
16.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
16.4
Pin Name Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
16.5
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .211
16.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
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16.7
SCI During Break Module Interrupts. . . . . . . . . . . . . . . . . . . .230
16.8
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
16.9
I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Section 17. Serial Peripheral Interface (SPI)
17.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .249
17.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
17.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
17.4
Pin Name Conventions and I/O Register Addresses . . . . . . . 251
17.5
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .252
17.6
Transmission Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .256
17.7
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .265
17.8
Queuing Transmission Data . . . . . . . . . . . . . . . . . . . . . . . . . . 266
17.9
Resetting the SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
17.10 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
17.11 SPI During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . 269
17.12 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
17.13 I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Section 18. Timer Interface Module B (TIMB)
18.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .281
18.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
18.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
18.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .284
18.5
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .292
18.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.7
TIMB During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 293
18.8
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
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18.9
I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
Section 19. Programmable Interrupt Timer (PIT)
19.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .305
19.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
19.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
19.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .306
19.5
PIT Counter Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307
19.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
19.7
PIT During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . 308
19.8
I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
Section 20. I/O Ports
20.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .315
20.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
20.3
Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
20.4
Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
20.5
Port C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
20.6
Port D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
20.7
Port E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
20.8
Port F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
20.9
Port G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
20.10 Port H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
Section 21. MSCAN08 Controller (MSCAN08)
21.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .343
21.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344
21.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345
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21.4
External Pins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
21.5
Message Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
21.6
Identifier Acceptance Filter . . . . . . . . . . . . . . . . . . . . . . . . . . .352
21.7
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .357
21.8
Protocol Violation Protection. . . . . . . . . . . . . . . . . . . . . . . . . . 359
21.9
Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
21.10 Timer Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
21.11 Clock System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .364
21.12 Memory Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368
21.13 Programmer’s Model of Message Storage . . . . . . . . . . . . . . . 368
21.14 Programmer’s Model of Control Registers . . . . . . . . . . . . . . . 374
Section 22. Keyboard Module (KBD)
22.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .395
22.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
22.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
22.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .396
22.5
Keyboard Initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
22.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
22.7
Keyboard Module During Break Interrupts . . . . . . . . . . . . . . . 400
22.8
I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
Section 23. Timer Interface Module A (TIMA)
23.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .403
23.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
23.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
23.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .407
23.5
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .417
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23.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
23.7
TIMA During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 418
23.8
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
23.9
I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
Section 24. Analog-to-Digital Converter (ADC-15)
24.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .433
24.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
24.3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
24.4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .434
24.5
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .437
24.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
24.7
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
24.8
I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Section 25. Electrical Specifications
25.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .445
25.2
Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .446
25.3
Functional Operating Range. . . . . . . . . . . . . . . . . . . . . . . . . . 447
25.4
Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
25.5
5.0 Volt DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . 448
25.6
Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
25.7
ADC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
25.8
5.0 Vdc ± 0.5 V Serial Peripheral Interface (SPI) Timing . . . . 451
25.9
CGM Operating Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . .454
25.10 CGM Component Information. . . . . . . . . . . . . . . . . . . . . . . . . 454
25.11 CGM Acquisition/Lock Time Information . . . . . . . . . . . . . . . . 455
25.12 RAM Memory Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 456
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25.13 EEPROM Memory Characteristics . . . . . . . . . . . . . . . . . . . . . 456
25.14 Mechanical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
Section 26. MC68HC08AZ60A Changes
26.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .459
26.2
Significant Changes from the MC68HC08AZ60 (Non-A Suffix Device)459
Section 27. MC68HC08AZ48A Memory Map
27.1
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .463
27.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
Revision History
27.3
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .467
27.4
Changes Between Revision 2.0 and Revision 1.0 . . . . . . . . . 467
27.5
Changes Between Revision 1.0 and Revision 0.0 . . . . . . . . . 467
Glossary
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1-1
1-2
1-3
2-1
2-2
2-3
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
7-1
7-2
7-3
Title
MC68HC08AZ60A MCU Block Diagram . . . . . . . . . . . . . . . . . 30
64 QFP Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Power Supply Bypassing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Memory Map (Continued) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
I/O Data, Status and Control Registers . . . . . . . . . . . . . . . . . . 45
Additional Status and Control Registers . . . . . . . . . . . . . . . . . . 50
EEPROM-1 Register Summary . . . . . . . . . . . . . . . . . . . . . . . .61
EEPROM-1 Control Register (EE1CR). . . . . . . . . . . . . . . . . . . 69
EEPROM-1 Array Configuration Register (EE1ACR). . . . . . . . 71
EEPROM-1 Nonvolatile Register (EE1NVR) . . . . . . . . . . . . . . 73
EE1DIV Divider High Register (EE1DIVH) . . . . . . . . . . . . . . . . 74
EE1DIV Divider Low Register (EE1DIVL). . . . . . . . . . . . . . . . . 74
EEPROM-1 Divider Non-Volatile Register High (EE1DIVHNVR))
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
EEPROM-1 Divider Non-Volatile Register Low (EE1DIVLNVR)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
EEPROM-2 Register Summary . . . . . . . . . . . . . . . . . . . . . . . .81
EEPROM-2 Control Register (EE2CR). . . . . . . . . . . . . . . . . . . 89
EEPROM-2 Array Configuration Register (EE2ACR). . . . . . . . 91
EEPROM-2 Nonvolatile Register (EE2NVR) . . . . . . . . . . . . . . 93
EE2DIV Divider High Register (EE2DIVH) . . . . . . . . . . . . . . . . 94
EE2DIV Divider Low Register (EE2DIVL). . . . . . . . . . . . . . . . . 94
EEPROM-2 Divider Non-Volatile Register High (EE2DIVHNVR))
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
EEPROM-2 Divider Non-Volatile Register Low (EE2DIVLNVR)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
CPU Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Accumulator (A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Index Register (H:X) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
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List of Figures
7-4
7-5
7-6
8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
8-9
8-10
8-11
8-12
8-13
8-14
8-15
8-16
8-17
9-1
9-2
9-3
9-4
9-5
9-6
10-1
10-2
11-1
11-2
11-3
12-1
12-2
12-3
12-4
12-5
12-6
13-1
Stack Pointer (SP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Program Counter (PC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103
Condition Code Register (CCR) . . . . . . . . . . . . . . . . . . . . . . . 103
SIM Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
CGM Clock Signals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
External Reset Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
Internal Reset Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Sources of Internal Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
POR Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Interrupt Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Interrupt Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Interrupt Recognition Example . . . . . . . . . . . . . . . . . . . . . . . . 129
WAIT Mode Entry Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
WAIT Recovery From Interrupt or Break . . . . . . . . . . . . . . . . 132
WAIT Recovery From Internal Reset . . . . . . . . . . . . . . . . . . . 132
STOP Mode Entry Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
STOP Mode Recovery From Interrupt . . . . . . . . . . . . . . . . . . 134
SIM Break Status Register (SBSR) . . . . . . . . . . . . . . . . . . . . 134
SIM Reset Status Register (SRSR) . . . . . . . . . . . . . . . . . . . . 136
SIM Break Flag Control Register (SBFCR) . . . . . . . . . . . . . . 137
CGM Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143
CGM External Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 151
PLL Control Register (PCTL) . . . . . . . . . . . . . . . . . . . . . . . . . 153
PLL Bandwidth Control Register (PBWC) . . . . . . . . . . . . . . . 155
PLL Programming Register (PPG) . . . . . . . . . . . . . . . . . . . . . 157
Mask Option Register A (MORA) . . . . . . . . . . . . . . . . . . . . . . 168
Mask Option Register B (MORB) . . . . . . . . . . . . . . . . . . . . . . 170
Break Module Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 173
Break Status and Control Register (BRKSCR). . . . . . . . . . . . 175
Break Address Registers (BRKH and BRKL) . . . . . . . . . . . . . 176
Monitor Mode Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Monitor Data Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Sample Monitor Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Read Transaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182
Break Transaction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182
Monitor Mode Entry Timing. . . . . . . . . . . . . . . . . . . . . . . . . . .187
COP Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Technical Data
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List of Figures
13-2
14-1
14-2
15-1
15-2
15-3
16-1
16-2
16-3
16-4
16-5
16-6
16-7
16-8
16-9
16-10
16-11
16-12
16-13
16-14
16-15
16-16
16-17
16-18
17-1
17-2
17-3
17-4
17-5
17-6
17-7
17-8
17-9
17-10
17-11
17-12
17-13
17-14
COP Control Register (COPCTL) . . . . . . . . . . . . . . . . . . . . . . 193
LVI Module Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . .197
LVI Status Register (LVISR) . . . . . . . . . . . . . . . . . . . . . . . . . . 198
IRQ Module Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 202
IRQ Interrupt Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
IRQ Status and Control Register (ISCR) . . . . . . . . . . . . . . . . 206
SCI Module Block Diagram
. . . . . . . . . . . . . . . . . . . . . . . . 212
SCI I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . .213
SCI Data Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214
SCI Transmitter
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
SCI Transmitter I/O Register Summary . . . . . . . . . . . . . . . . . 217
SCI Receiver Block Diagram
. . . . . . . . . . . . . . . . . . . . . . 220
SCI I/O Receiver Register Summary . . . . . . . . . . . . . . . . . . . 221
Receiver Data Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Slow Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Fast Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
SCI Control Register 1 (SCC1). . . . . . . . . . . . . . . . . . . . . . . . 232
SCI Control Register 2 (SCC2). . . . . . . . . . . . . . . . . . . . . . . . 235
SCI Control Register 3 (SCC3). . . . . . . . . . . . . . . . . . . . . . . . 237
SCI Status Register 1 (SCS1) . . . . . . . . . . . . . . . . . . . . . . . . 239
Flag Clearing Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
SCI Status Register 2 (SCS2) . . . . . . . . . . . . . . . . . . . . . . . . 243
SCI Data Register (SCDR) . . . . . . . . . . . . . . . . . . . . . . . . . . .244
SCI Baud Rate Register (SCBR) . . . . . . . . . . . . . . . . . . . . . . 245
SPI I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . .252
SPI Module Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . .253
Full-duplex Master-Slave Connections . . . . . . . . . . . . . . . . . . 255
Transmission Format (CPHA = ‘0’). . . . . . . . . . . . . . . . . . . . . 258
Transmission Format (CPHA = ‘1’). . . . . . . . . . . . . . . . . . . . . 258
Transmission Start Delay (Master) . . . . . . . . . . . . . . . . . . . . . 260
Missed Read of Overflow Condition . . . . . . . . . . . . . . . . . . . .262
Clearing SPRF When OVRF Interrupt is Not Enabled . . . . . . 263
SPI Interrupt Request Generation . . . . . . . . . . . . . . . . . . . . . 266
SPRF/SPTE CPU Interrupt Timing . . . . . . . . . . . . . . . . . . . . . 267
CPHA/SS Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
SPI Control Register (SPCR) . . . . . . . . . . . . . . . . . . . . . . . . . 274
SPI Status and Control Register (SPSCR) . . . . . . . . . . . . . . . 277
SPI Data Register (SPDR) . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
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List of Figures
18-1
18-2
18-3
18-4
18-5
18-6
18-7
18-8
18-9
19-1
19-2
19-3
19-4
19-5
20-1
20-2
20-3
20-4
20-5
20-6
20-7
20-8
20-9
20-10
20-11
20-12
20-13
20-14
20-15
20-16
20-17
20-18
20-19
20-20
20-21
20-22
20-23
TIMB Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
TIMB I/O Register Summary. . . . . . . . . . . . . . . . . . . . . . . . . . 283
PWM Period and Pulse Width . . . . . . . . . . . . . . . . . . . . . . . . 288
TIMB Status and Control Register (TBSC) . . . . . . . . . . . . . . . 295
TIMB Counter Registers (TBCNTH and TBCNTL) . . . . . . . . . 297
TIMB Counter Modulo Registers (TBMODH and TBMODL) . 298
TIMB Channel Status and Control Registers (TBSC0–TBSC1)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
CHxMAX Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .303
TIMB Channel Registers (TBCH0H/L–TBCH1H/L) . . . . . . . . 304
PIT Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
PIT I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
PIT Status and Control Register (PSC) . . . . . . . . . . . . . . . . . 310
PIT Counter Registers (PCNTH–PCNTL). . . . . . . . . . . . . . . . 312
PIT Counter Modulo Registers (PMODH–PMODL) . . . . . . . . 313
Port A data register (PTA) . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
Data Direction Register A (DDRA). . . . . . . . . . . . . . . . . . . . . 318
Port A I/O Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
Port B Data Register (PTB) . . . . . . . . . . . . . . . . . . . . . . . . . . 320
Data Direction Register B (DDRB) . . . . . . . . . . . . . . . . . . . . . 321
Port B I/O Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
Port C Data Register (PTC) . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Data Direction Register C (DDRC) . . . . . . . . . . . . . . . . . . . . . 324
Port C I/O Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Port D Data Register (PTD) . . . . . . . . . . . . . . . . . . . . . . . . . . 326
Data Direction Register D (DDRD) . . . . . . . . . . . . . . . . . . . . . 327
Port D I/O Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
Port E Data Register (PTE) . . . . . . . . . . . . . . . . . . . . . . . . . . 329
Data Direction Register E (DDRE) . . . . . . . . . . . . . . . . . . . . . 332
Port E I/O Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Port F Data Register (PTF). . . . . . . . . . . . . . . . . . . . . . . . . . .334
Data Direction Register F (DDRF) . . . . . . . . . . . . . . . . . . . . . 335
Port F I/O Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
Port G Data Register (PTG) . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Data Direction Register G (DDRG). . . . . . . . . . . . . . . . . . . . . 338
Port G I/O Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
Port H Data Register (PTH) . . . . . . . . . . . . . . . . . . . . . . . . . . 340
Data Direction Register H (DDRH) . . . . . . . . . . . . . . . . . . . . . 341
Technical Data
20
MC68HC08AZ60A — Rev 2.1
List of Figures
Freescale Semiconductor
List of Figures
20-24
21-1
21-2
21-3
21-4
21-5
21-6
21-7
21-8
21-9
21-10
21-11
21-12
21-13
21-14
21-15
21-16
21-17
21-18
21-19
21-20
21-21
21-22
21-23
21-24
21-25
21-26
21-27
22-1
22-2
22-3
22-4
23-1
23-2
23-3
23-4
23-5
Port H I/O Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
The CAN System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
User Model for Message Buffer Organization. . . . . . . . . . . . . 350
Single 32-Bit Maskable Identifier Acceptance Filter . . . . . . . . 353
Dual 16-Bit Maskable Acceptance Filters . . . . . . . . . . . . . . . . 354
Quadruple 8-Bit Maskable Acceptance Filters . . . . . . . . . . . . 355
Sleep Request/Acknowledge Cycle . . . . . . . . . . . . . . . . . . . . 362
Clocking Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
Segments Within the Bit Time . . . . . . . . . . . . . . . . . . . . . . . . 367
MSCAN08 Memory Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368
Message Buffer Organization . . . . . . . . . . . . . . . . . . . . . . . . . 369
Receive/Transmit Message Buffer Extended Identifier (IDRn)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
Standard Identifier Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . 372
Transmit Buffer Priority Register (TBPR) . . . . . . . . . . . . . . . . 374
MSCAN08 Control Register Structure . . . . . . . . . . . . . . . . . . 375
Module Control Register 0 (CMCR0) . . . . . . . . . . . . . . . . . . . 377
Module Control Register (CMCR1). . . . . . . . . . . . . . . . . . . . . 379
Bus Timing Register 0 (CBTR0) . . . . . . . . . . . . . . . . . . . . . . . 380
Bus Timing Register 1 (CBTR1) . . . . . . . . . . . . . . . . . . . . . . . 381
Receiver Flag Register (CRFLG) . . . . . . . . . . . . . . . . . . . . . . 383
Receiver Interrupt Enable Register (CRIER) . . . . . . . . . . . . . 385
Transmitter Flag Register (CTFLG) . . . . . . . . . . . . . . . . . . . . 387
Transmitter Control Register (CTCR) . . . . . . . . . . . . . . . . . . . 388
Identifier Acceptance Control Register (CIDAC). . . . . . . . . . . 389
Receiver Error Counter (CRXERR) . . . . . . . . . . . . . . . . . . . . 391
Transmit Error Counter (CTXERR). . . . . . . . . . . . . . . . . . . . . 391
Identifier Acceptance Registers (CIDAR0–CIDAR3) . . . . . . . 392
Identifier Mask Registers (CIDMR0–CIDMR3) . . . . . . . . . . . . 393
Keyboard Module Block Diagram . . . . . . . . . . . . . . . . . . . . 397
I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .397
Keyboard Status and Control Register (KBSCR) . . . . . . . . . . 401
Keyboard Interrupt Enable Register (KBIER) . . . . . . . . . . . . . 402
TIMA Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
TIMA I/O Register Summary. . . . . . . . . . . . . . . . . . . . . . . . . . 406
PWM Period and Pulse Width . . . . . . . . . . . . . . . . . . . . . . . . 412
TIMA Status and Control Register (TASC) . . . . . . . . . . . . . . . 420
TIMA Counter Registers (TACNTH and TACNTL) . . . . . . . . . 422
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
List of Figures
21
List of Figures
23-6 TIMA Counter Modulo Registers (TAMODH and TAMODL) . 423
23-7 TIMA Channel Status and Control Registers (TASC0–TASC5)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
23-8 CHxMAX Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .429
23-9 TIMA Channel Registers (TACH0H/L–TACH5H/L) . . . . . . . . 430
24-1 ADC Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
24-2 ADC Status and Control Register (ADSCR) . . . . . . . . . . . . . . 439
24-3 ADC Data Register (ADR) . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
24-4 ADC Input Clock Register (ADICLK) . . . . . . . . . . . . . . . . . . . 442
25-1 SPI Master Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 452
25-2 SPI Slave Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
25-3 64-pin QFP (Case #840B) . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
27-1 Memory Map (Continued) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
Technical Data
22
MC68HC08AZ60A — Rev 2.1
List of Figures
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
List of Tables
Table
1-1
1-2
1-3
1-4
2-1
5-1
5-2
5-3
5-4
6-1
6-2
6-3
6-4
7-1
7-2
8-1
8-2
8-3
8-4
9-1
9-2
9-3
11-1
12-1
12-2
12-3
12-4
12-5
12-6
Title
External Pins Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Signal Name Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Clock Source Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
MC Order Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Vector addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
EEPROM-1 Array Address Blocks . . . . . . . . . . . . . . . . . . . . . . 64
Example Selective Bit Programming Description . . . . . . . . . . . 65
EEPROM-1 Program/Erase Mode Select. . . . . . . . . . . . . . . . . 70
EEPROM-1 Block Protect and Security Summary . . . . . . . . . . 72
EEPROM-2 Array Address Blocks . . . . . . . . . . . . . . . . . . . . . . 84
Example Selective Bit Programming Description . . . . . . . . . . . 85
EEPROM-2 Program/Erase Mode Select. . . . . . . . . . . . . . . . . 90
EEPROM-2 Block Protect and Security Summary . . . . . . . . . . 92
Instruction Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Opcode Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
SIM I/O Register Summary. . . . . . . . . . . . . . . . . . . . . . . . . . .119
Signal Naming Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 120
PIN Bit Set Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
SIM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
I/O Register Address Summary . . . . . . . . . . . . . . . . . . . . . . .143
Variable Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
VCO Frequency Multiplier (N) Selection. . . . . . . . . . . . . . . . . 158
Break I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . 173
Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Mode Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
READ (Read Memory) Command . . . . . . . . . . . . . . . . . . . . . 183
WRITE (Write Memory) Command. . . . . . . . . . . . . . . . . . . . . 183
IREAD (Indexed Read) Command . . . . . . . . . . . . . . . . . . . . . 184
IWRITE (Indexed Write) Command . . . . . . . . . . . . . . . . . . . . 184
MC68HC08AZ60A — Rev 2.1
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Technical Data
List of Tables
23
List of Tables
12-7
12-8
13-1
14-1
14-2
15-1
16-1
16-2
16-3
16-4
16-5
16-6
16-7
16-8
16-9
16-10
16-11
17-1
17-2
17-3
17-4
17-5
18-1
18-2
19-1
19-2
20-1
20-2
20-3
20-4
20-5
20-6
20-7
20-8
20-9
21-1
21-2
21-3
READSP (Read Stack Pointer) Command . . . . . . . . . . . . . . . 185
RUN (Run User Program) Command . . . . . . . . . . . . . . . . . . . 185
COP I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 190
LVI I/O Register Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
LVIOUT Bit Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
IRQ I/O Register Summary. . . . . . . . . . . . . . . . . . . . . . . . . . .203
Pin Name Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
SCI I/O Register Address Summary . . . . . . . . . . . . . . . . . . . .213
SCI Transmitter I/O Address Summary . . . . . . . . . . . . . . . . . 217
SCI Receiver I/O Address Summary . . . . . . . . . . . . . . . . . . . 221
Start Bit Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Data Bit Recovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224
Stop Bit Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224
Character Format Selection . . . . . . . . . . . . . . . . . . . . . . . . . . 234
SCI Baud Rate Prescaling . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
SCI Baud Rate Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
SCI Baud Rate Selection Examples . . . . . . . . . . . . . . . . . . . .247
Pin Name Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
I/O Register Addresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
SPI Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .265
SPI Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
SPI Master Baud Rate Selection . . . . . . . . . . . . . . . . . . . . . . 279
Prescaler Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
Mode, Edge, and Level Selection . . . . . . . . . . . . . . . . . . . . . . 302
PIT I/O Register Address Summary . . . . . . . . . . . . . . . . . . . .307
Prescaler Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
I/O Port Register Summary. . . . . . . . . . . . . . . . . . . . . . . . . . .316
Port A pin functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Port B Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Port C Pin Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Port D Pin Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
Port E Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
Port F Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
Port G Pin Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Port H Pin Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
MSCAN08 Interrupt Vector Addresses . . . . . . . . . . . . . . . . . . 359
MSCAN08 vs CPU Operating Modes . . . . . . . . . . . . . . . . . . . 360
Time segment syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
Technical Data
24
MC68HC08AZ60A — Rev 2.1
List of Tables
Freescale Semiconductor
List of Tables
21-4
21-5
21-6
21-7
21-8
21-9
21-10
22-1
23-1
23-2
24-1
24-2
CAN Standard Compliant Bit Time Segment Settings . . . . . . 367
Data Length Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Synchronization Jump Width . . . . . . . . . . . . . . . . . . . . . . . . . 380
Baud Rate Prescaler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
Time Segment Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .382
Identifier Acceptance Mode Settings . . . . . . . . . . . . . . . . . . . 390
Identifier Acceptance Hit Indication . . . . . . . . . . . . . . . . . . . . 390
I/O Register Address Summary . . . . . . . . . . . . . . . . . . . . . . .397
Prescaler Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
Mode, Edge, and Level Selection . . . . . . . . . . . . . . . . . . . . . . 428
Mux Channel Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
ADC Clock Divide Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
List of Tables
25
List of Tables
Technical Data
26
MC68HC08AZ60A — Rev 2.1
List of Tables
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 1. General Description
1.1 Contents
1.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
1.4
Pin Assignments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
1.4.1
Power Supply Pins (VDD and VSS) . . . . . . . . . . . . . . . . . . . 32
1.4.2
Oscillator Pins (OSC1 and OSC2). . . . . . . . . . . . . . . . . . . 33
1.4.3
External Reset Pin (RST) . . . . . . . . . . . . . . . . . . . . . . . . . . 33
1.4.4
External Interrupt Pin (IRQ) . . . . . . . . . . . . . . . . . . . . . . . . 33
1.4.5
Analog Power Supply Pin (VDDA) . . . . . . . . . . . . . . . . . . . 33
1.4.6
Analog Ground Pin (VSSA) . . . . . . . . . . . . . . . . . . . . . . . . . 33
1.4.7
ADC Analog Ground Pin (Avss/VREFL) . . . . . . . . . . . . . . . 33
1.4.8
ADC Reference High Voltage Pin (VREFH) . . . . . . . . . . . 34
1.4.9
ADC Analog Power Supply Pin (VDDAREF) . . . . . . . . . . . . 34
1.4.10 External Filter Capacitor Pin (CGMXFC) . . . . . . . . . . . . . 34
1.4.11 Port A Input/Output (I/O) Pins (PTA7–PTA0) . . . . . . . . . . 34
1.4.12 Port B I/O Pins (PTB7/ATD7–PTB0/ATD0) . . . . . . . . . . . . 34
1.4.13 Port C I/O Pins (PTC5–PTC0) . . . . . . . . . . . . . . . . . . . . . . 34
1.4.14 Port D I/O Pins (PTD7–PTD0/ATD8) . . . . . . . . . . . . . . . . . 35
1.4.15 Port E I/O Pins (PTE7/SPSCK–PTE0/TxD) . . . . . . . . . . . . 35
1.4.16 Port F I/O Pins (PTF6–PTF0/TACH2). . . . . . . . . . . . . . . . . 35
1.4.17 Port G I/O Pins (PTG2/KBD2–PTG0/KBD0) . . . . . . . . . . . 35
1.4.18 Port H I/O Pins (PTH1/KBD4–PTH0/KBD3). . . . . . . . . . . . 36
1.4.19 CAN Transmit Pin (CANTx) . . . . . . . . . . . . . . . . . . . . . . . . 36
1.4.20 CAN Receive Pin (CANRx). . . . . . . . . . . . . . . . . . . . . . . . . 36
1.5
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
1.5.1
MC Order Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
General Description
27
General Description
1.2 Introduction
The MC68HC08AZ60A is a member of the low-cost, high-performance
M68HC08 Family of 8-bit microcontroller units (MCUs). The M68HC08
Family is based on the customer-specified integrated circuit (CSIC)
design strategy. All MCUs in the family use the enhanced M68HC08
central processor unit (CPU08) and are available with a variety of
modules, memory sizes and types, and package types.
1.3 Features
Features of the MC68HC08AZ60A include the following:
•
High-Performance M68HC08 Architecture
•
Fully Upward-Compatible Object Code with M6805, M146805,
and M68HC05 Families
•
8.4MHz Internal Bus Frequency at 125°C
•
MSCAN08 Controller (Scalable CAN) (Implementing CAN 2.0b
Protocol as Defined in BOSCH Specification Sep. 1991)
•
Available in 64 QFP Package
•
61,744 Bytes User ROM
•
User ROM Data security
•
1024 Bytes of On-Chip EEPROM with Security Feature
•
2048 Bytes of On-Chip RAM
•
Serial Peripheral Interface (SPI) Module
•
Serial Communications Interface (SCI) Module
•
16-bit Timer Interface Module (TIMA-6) with Six Input
Capture/Output Compare Channels
•
16-bit Timer Interface Module (TIMB) with Two Input
Capture/Output Compare Channels
•
Programmable Interrupt Timer (PIT)
•
Clock Generator Module (CGM)
Technical Data
28
MC68HC08AZ60A — Rev 2.1
General Description
Freescale Semiconductor
General Description
•
8-Bit, 15-Channel Analog to Digital Convertor (ADC-15)
•
5-Bit Keyboard Interrupt Module
•
System Protection Features
– Computer Operating Properly (COP) with Optional Reset
– Low-Voltage Detection with Optional Reset
– Illegal Opcode Detection with Optional Reset
– Illegal Address Detection with Optional Reset
•
Low-Power Design (Fully Static with STOP and WAIT Modes)
•
Master Reset Pin and Power-On Reset
Features of the CPU08 include the following:
•
Enhanced HC05 Programming Model
•
Extensive Loop ControlFunctions
•
16 Addressing Modes (8 more than the HC05)
•
16-Bit Index Register and Stack Pointer
•
Memory-to-Memory Data Transfers
•
Fast 8 × 8 Multiply Instruction
•
Fast 16/8 Divide Instruction
•
Binary-Coded Decimal (BCD) Instructions
•
Optimization for Controller Applications
•
‘C’ Language Support
Figure 1-1 shows the structure of the MC68HC08AZ60A
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
General Description
29
USER RAM — 2048 BYTES
BREAK
MODULE
PTA
MSCAN08 CONTROLLER
MODULE
DDRA
CONTROL AND STATUS REGISTERS
PTB
CANRx
CANTx
PTA7–PTA0
DDRB
SERIAL COMMUNICATIONS
INTERFACE MODULE
ARITHMETIC/LOGIC
UNIT (ALU)
PTB7/ATD7–PTB0/ATD0
PTC
CPU
REGISTERS
DDRC
M68HC08 CPU
USER ROM — 61,744 BYTES
VSSA
POWER-ON RESET
MODULE
KEYBOARD INTERRUPT
MODULE
POWER
DDRE
PTE
PROGRAMMABLE INTERRUPT TIMER
MODULE
VDD
PTF
Freescale Semiconductor
MC68HC08AZ60A — Rev 2.1
IRQ
MODULE
VSS
PTE7/SPSCK
PTE6/MOSI
PTE5/MISO
PTE4/SS
PTE3/TACH1
PTE2/TACH0
PTE1/RxD
PTE0/TxD
PTF6
PTF5/TBCH1–
PTF4/TBCH0
PTF3/TACH5–
PTF0/TACH2
PTG2/KBD2–
PTG0/KBD0
PTH1/KBD4–
PTH0/KBD3
ANALOG TO DIGITAL CONVERTOR
MODULE
VREFH
AVSS/VREFL
VDDAREF
VDDA
Figure 1-1. MC68HC08AZ60A MCU Block Diagram
DDRF
IRQ
SYSTEM INTEGRATION
MODULE
SERIAL PERIPHERAL INTERFACE
MODULE
PTD3/ATD11–
PTD0/ATD8
PTG
RST
CLOCK GENERATOR
MODULE
DDRG
OSC1
OSC2
CGMXFC
PTD7
PTD6/ATD14/TACLK
PTD5/ATD13
PTD4/ATD12/TBCLK
PTH
TIMERA & B INTERFACE
MODULES
(6 + 2 Channels)
USER ROM VECTOR SPACE — 52 BYTES
DDRH
General Description
MONITOR ROM — 256 BYTES
COMPUTER OPERATING PROPERLY
MODULE
PTD
LOW VOLTAGE INHIBIT
MODULE
DDRD
USER EEPROM — 1024 BYTES
PTC5-PTC3
PTC2/MCLK
PTC1–PTC0
General Description
Technical Data
30
.
General Description
1.4 Pin Assignments
PTC1
PTC0
OSC1
OSC2
CGMXFC
VSSA
vDDA
VREFH
PTD7
PTD6/ATD14/TACLK
PTD5/ATD13
PTD4/ATD12/TBCLK
61
60
59
58
57
56
55
54
53
52
51
50
1
PTH1/KBD4
PTC2/MCLK
62
PTC4
49
PTC3
63
64
PTC5
Figure 1-2 shows the 64 QFP pin assignments.
48
PTH0/KBD3
IRQ
2
47
PTD3/ATD11
RST
3
46
PTD2/ATD10
PTF0/TACH2
4
45
AVSS/VREFL
PTF1/TACH3
5
44
VDDAREF
PTF2/TACH4
6
43
PTD1/ATD9
PTF3/TACH5
7
42
PTD0/ATD8
PTF4/TBCH0
8
41
PTB7/ATD7
CANRx
9
40
PTB6/ATD6
CANTx
10
39
PTB5/ATD5
PTF5/TBCH1
11
38
PTB4/ATD4
PTF6
12
37
PTB3/ATD3
PTE0/TxD
13
36
PTB2/ATD2
PTE1/RxD
14
35
PTB1/ATD1
PTE2/TACH0
15
34
PTB0/ATD0
20
21
22
23
24
25
26
27
28
29
30
31
PTE7/SPSCK
VSS
VDD
PTG0/KBD0
PTG1/KBD1
PTG2/KBD2
PTA0
PTA1
PTA2
PTA3
PTA4
PTA5
33
PTA7
PTA6 32
19
PTE5/MISO
PTE4/SS 17
18
PTE3/TACH1 16
PTE6/MOSI
MC68HC08AZ60A
Figure 1-2. 64 QFP Pin Assignments
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
General Description
31
General Description
1.4.1 Power Supply Pins (VDD and VSS)
VDD and VSS are the power supply and ground pins. The MCU operates
from a single power supply.
Fast signal transitions on MCU pins place high, short-duration current
demands on the power supply. To prevent noise problems, take special
care to provide power supply bypassing at the MCU as Figure 1-3
shows. Place the C1 bypass capacitor as close to the MCU as possible.
Use a high-frequency-response ceramic capacitor for C1. C2 is an
optional bulk current bypass capacitor for use in applications that require
the port pins to source high current levels.
MCU
VSS
VDD
C1
0.1 µF
+
C2
VDD
NOTE: Component values shown
represent typical applications.
Figure 1-3. Power Supply Bypassing
VSS is also the ground for the port output buffers and the ground return
for the serial clock in the Serial Peripheral Interface Module (SPI). See
Serial Peripheral Interface (SPI) on page 249.
NOTE:
VSS must be grounded for proper MCU operation.
Technical Data
32
MC68HC08AZ60A — Rev 2.1
General Description
Freescale Semiconductor
General Description
1.4.2 Oscillator Pins (OSC1 and OSC2)
The OSC1 and OSC2 pins are the connections for the on-chip oscillator
circuit. See Clock Generator Module (CGM) on page 139.
1.4.3 External Reset Pin (RST)
A logic ‘0’ on the RST pin forces the MCU to a known start-up state. RST
is bidirectional, allowing a reset of the entire system. It is driven low when
any internal reset source is asserted. See System Integration Module
(SIM) on page 117.
1.4.4 External Interrupt Pin (IRQ)
IRQ is an asynchronous external interrupt pin. See External Interrupt
Module (IRQ) on page 201.
1.4.5 Analog Power Supply Pin (VDDA)
VDDA is the power supply pin for the analog portion of the Clock
Generator Module (CGM). See Clock Generator Module (CGM) on
page 139.
1.4.6 Analog Ground Pin (VSSA)
VSSA is the ground connection for the analog portion of the Clock
Generator Module (CGM). See Clock Generator Module (CGM) on
page 139.
1.4.7 ADC Analog Ground Pin (Avss/VREFL)
The AVSS/VREFL pin provides both the analog ground connection and
the reference low voltage for the Analog-to-Digital Converter (ADC). See
Analog-to-Digital Converter (ADC-15) on page 433.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
General Description
33
General Description
1.4.8 ADC Reference High Voltage Pin (VREFH)
VREFH provides the reference high voltage for the Analog-to-Digital
Converter (ADC). See Analog-to-Digital Converter (ADC-15) on page
433.
1.4.9 ADC Analog Power Supply Pin (VDDAREF)
VDDAREF is the power supply pin for the analog portion of the Analog-toDigital Converter (ADC). See Analog-to-Digital Converter (ADC-15)
on page 433.
1.4.10 External Filter Capacitor Pin (CGMXFC)
CGMXFC is an external filter capacitor connection for the Clock
Generator Module (CGM). See Clock Generator Module (CGM) on
page 139.
1.4.11 Port A Input/Output (I/O) Pins (PTA7–PTA0)
PTA7–PTA0 are general-purpose bidirectional I/O port pins. See I/O
Ports on page 315.
1.4.12 Port B I/O Pins (PTB7/ATD7–PTB0/ATD0)
Port B is an 8-bit special function port that shares all eight pins with the
Analog to Digital Convertor (ADC). See Analog-to-Digital Converter
(ADC-15) on page 433 and I/O Ports on page 315.
1.4.13 Port C I/O Pins (PTC5–PTC0)
PTC5–PTC3 and PTC1–PTC0 are general-purpose bidirectional I/O
port pins. PTC2/MCLK is a special function port that shares its pin with
the system clock. See I/O Ports on page 315.
Technical Data
34
MC68HC08AZ60A — Rev 2.1
General Description
Freescale Semiconductor
General Description
1.4.14 Port D I/O Pins (PTD7–PTD0/ATD8)
Port D is an 8-bit special-function port that shares seven of its pins with
the Analog-to-Digital Converter Module (ADC-15), one of its pins with
the Timer Interface Module A (TIMA-6), and one more of its pins with the
Timer Interface Module B (TIMB). See Timer Interface Module A
(TIMA) on page 403 , Timer Interface Module B (TIMB) on page 281,
Analog-to-Digital Converter (ADC-15) on page 433 and I/O Ports on
page 315.
1.4.15 Port E I/O Pins (PTE7/SPSCK–PTE0/TxD)
Port E is an 8-bit special function port that shares two of its pins with the
Timer Interface Module A (TIMA), four of its pins with the Serial
Peripheral Interface Module (SPI), and two of its pins with the Serial
Communication Interface Module (SCI). See Serial Communications
Interface (SCI) on page 209, Serial Peripheral Interface (SPI) on page
249, Timer Interface Module A (TIMA) on page 403 and I/O Ports on
page 315.
1.4.16 Port F I/O Pins (PTF6–PTF0/TACH2)
Port F is a 7-bit special function port that shares its pins with the Timer
Interface Module B (TIMB). Six of its pins are shared with the Timer
Interface Module A (TIMA-6). See Timer Interface Module A (TIMA) on
page 403, Timer Interface Module B (TIMB) on page 281 and I/O Ports
on page 315.
1.4.17 Port G I/O Pins (PTG2/KBD2–PTG0/KBD0)
Port G is a 3-bit special function port that shares all of its pins with the
Keyboard Module (KBD). See Keyboard Module (KBD) on page 395
and I/O Ports on page 315.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
General Description
35
General Description
1.4.18 Port H I/O Pins (PTH1/KBD4–PTH0/KBD3)
Port H is a 2-bit special-function port that shares all of its pins with the
Keyboard Module (KBD). See Keyboard Module (KBD) on page 395
and I/O Ports on page 315.
1.4.19 CAN Transmit Pin (CANTx)
CANTx is the digital output from the MSCAN08 module. See MSCAN08
Controller (MSCAN08) on page 343.
1.4.20 CAN Receive Pin (CANRx)
CANRx is the digital input to the MSCAN08 module. See MSCAN08
Controller (MSCAN08) on page 343.
Table 1-1. External Pins Summary
PIN NAME
FUNCTION
HYSTERESIS(1)
DRIVER TYPE
RESET STATE
PTA7 – PTA0
General Purpose I/O
Dual State
No
Input (Hi-Z)
PTB7/ATD7 –
PTB0/ATD0
General Purpose I/0
/ ADC channel
Dual State
No
Input (Hi-Z)
PTC5 – PTC0
General Purpose I/O
Dual State
No
Input (Hi-Z)
PTD7
General Purpose I/O
Dual State
No
Input (Hi-Z)
PTD6/ATD14/TACLK
General Purpose I/O/ADC Channel/Timer A
External Input clock
Dual State
Yes (only for Timer A
function)
Input (Hi-Z)
PTD5/ATD13
General Purpose I/O/ADC Channel
Dual State
No
Input (Hi-Z)
PTD4/ATD12/TBCLK
General Purpose I/O
/ADC Channel/Timer B External Input Clock
Dual State
Yes (only for Timer B
function)
Input (Hi-Z)
PTD3/ATD11–PTD0/
ATD8
General Purpose I/O
/ADC channel
Dual State
No
Input (Hi-Z)
PTE7/SPSCK
General Purpose I/0
/ SPI clock
Dual State
(open drain)
Yes (only for SPI function)
Input (Hi-Z)
PTE6/MOSI
General Purpose I/0
/ SPI data path
Dual State
(open drain)
Yes (only for SPI function)
Input (Hi-Z)
PTE5/MISO
General Purpose I/0
/ SPI data path
Dual State
(open drain)
Yes (only for SPI function)
Input (Hi-Z)
Technical Data
36
MC68HC08AZ60A — Rev 2.1
General Description
Freescale Semiconductor
General Description
Table 1-1. External Pins Summary (Continued)
PIN NAME
FUNCTION
HYSTERESIS(1)
DRIVER TYPE
RESET STATE
PTE4/SS
General Purpose I/0
/ SPI Slave Select
Dual State
Yes (only for SPI function)
Input (Hi-Z)
PTE3/TACH1
General Purpose I/0
/ TimerA channel 1
Dual State
Yes (only for Timer A
function)
Input (Hi-Z)
PTE2/TACH0
General Purpose I/0
/ TimerA channel 0
Dual State
Yes (only for Timer A
function)
Input (Hi-Z)
PTE1/RxD
General Purpose I/0
/ SCI Receive Data
Dual State
Yes (only for SCI function)
Input (Hi-Z)
PTE0/TxD
General Purpose I/0
/ SCI Transmit Data
Dual State
No
Input (Hi-Z)
PTF6
General Purpose I/O
Dual State
No
Input (Hi-Z)
PTF5/TBCH1
General Purpose I/O
/Timer B Channel 1
Dual State
Yes (only for Timer B
function)
Input (Hi-Z)
PTF4/TBCH0
General Purpose I/0
/ Timer B Channel 0
Dual State
Yes (only for Timer B
function)
Input (Hi-Z)
PTF3/TACH5
General Purpose I/0/Timer A Channel 5
Dual State
Yes (only for Timer A
function)
Input (Hi-Z)
PTF2/TACH4
General Purpose I/0/Timer A Channel 4
Dual State
Yes (only for Timer A
function)
Input (Hi-Z)
PTF1/TACH3
General Purpose I/0
/Timer A Channel 3
Dual State
Yes (only for Timer A
function)
Input (Hi-Z)
PTF0/TACH2
General Purpose I/0
/Timer A channel 2
Dual State
Yes (only for Timer A
function)
Input (Hi-Z)
PTG2/KBD2 –
PTG0/KBD0
General Purpose I/0/Keyboard Wakeup Pin
Dual State
Yes (only for KBD
function)
Input (Hi-Z)
PTH1/KBD4–
PTH0/KBD3
General Purpose I/0/Keyboard Wakeup Pin
Dual State
Yes (only for KBD
function)
Input (Hi-Z)
VDD
Logical Chip Power Supply
NA
NA
NA
VSS
Logical Chip Ground
NA
NA
NA
VDDA
CGM Analog Power Supply
NA
NA
NA
VSSA
CGM Analog Ground
NA
NA
NA
VREFH
ADC Reference High Voltage
NA
NA
NA
AVSS/VREFL
ADC Gnd & Reference Low Voltage
NA
NA
NA
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
General Description
37
General Description
Table 1-1. External Pins Summary (Continued)
PIN NAME
FUNCTION
HYSTERESIS(1)
DRIVER TYPE
RESET STATE
VDDAREF
ADC Power supply
NA
NA
NA
OSC1
External Clock In
NA
YES
Input (Hi-Z)
OSC2
External Clock Out
NA
NA
Output
CGMXFC
PLL Loop Filter Cap
NA
NA
NA
IRQ
External Interrupt Request
NA
YES
Input (Hi-Z)
RST
Reset
NA
YES
Input (Hi-Z)
CANRx
MSCAN08 Serial Input
NA
YES
Input (Hi-Z)
CANTx
MSCAN08 Serial Output
Output
NA
Output
1. Hysteresis is not 100% tested but is typically a minimum of 300mV.
Details of the clock connections to each of the modules on the
MC68HC08AZ60A are shown in Table 1-3. A short description of each
clock source is also given in Table 1-2.
Table 1-2. Signal Name Conventions
Signal name
Description
CGMXCLK
Buffered version of OSC1 from Clock Generator Module (CGM)
CGMOUT
PLL-based or OSC1-based clock output from Clock Generator Module
(CGM)
Bus Clock
CGMOUT divided by two
SPSCK
SPI serial clock
TACLK
External clock Input for TIMA
TBCLK
External clock Input for TIMB
Table 1-3. Clock Source Summary
Module
Clock source
ADC
CGMXCLK or Bus Clock
MSCAN08
CGMXCLK or CGMOUT
COP
CGMXCLK
CPU
Bus Clock
Technical Data
38
MC68HC08AZ60A — Rev 2.1
General Description
Freescale Semiconductor
General Description
Table 1-3. Clock Source Summary (Continued)
Module
EEPROM
Clock source
CGMXCLK or Bus Clock
ROM
Bus Clock
RAM
Bus Clock
SPI
Bus Clock/SPSCK
SCI
CGMXCLK
TIMA
Bus Clock or PTD6/ATD14/TACLK
TIMB
Bus Clock or PTD4/ATD12/TBCLK
PIT
Bus Clock
KBI
Bus Clock
SIM
CGMOUT and CGMXCLK
IRQ
Bus Clock
BRK
Bus Clock
LVI
Bus Clock
CGM
OSC1 and OSC2
1.5 Ordering Information
This section contains instructions for ordering the MC68HC08AZ60A.
1.5.1 MC Order Numbers
Table 1-4. MC Order Numbers
MC Order Number
MC68HC08AZ60ACFU
– 40 °C to + 85°C
MC68HC08AZ60AVFU
– 40 °C to + 105 °C
MC68HC08AZ60AMFU
– 40 °C to + 125 °C
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Operating
Temperature Range
Technical Data
General Description
39
General Description
Technical Data
40
MC68HC08AZ60A — Rev 2.1
General Description
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 2. Memory Map
2.1 Contents
2.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.3
I/O Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.4
Additional Status and Control Registers . . . . . . . . . . . . . . . 50
2.5
Vector Addresses and Priority . . . . . . . . . . . . . . . . . . . . . . . 52
2.2 Introduction
The CPU08 can address 64K bytes of memory space. The memory
map, shown in Figure 2-1, includes:
•
61,744 Bytes of ROM
•
2048 Bytes of RAM
•
1024 Bytes of EEPROM with Protect Option
•
52 Bytes of User-Defined Vectors
•
256 Bytes of Monitor ROM
The following definitions apply to the memory map representation of
reserved and unimplemented locations.
•
Reserved — Accessing a reserved location can have
unpredictable effects on MCU operation.
•
Unused — These locations are reserved in the memory map for
future use, accessing an unused location can have unpredictable
effects on MCU operation.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Memory Map
41
Memory Map
•
Unimplemented — Accessing an unimplemented location can
cause an illegal address reset (within the constraints as outlined
in the System Integration Module (SIM)).
MC68HC08AZ60A
$0000
↓
$004F
I/O REGISTERS (80 BYTES)
$0050
↓
$044F
RAM-1, 1024 BYTES
$0450
↓
$04FF
ROM-2, 176 BYTES
$0500
↓
$057F
CAN CONTROL AND MESSAGE
BUFFERS, 128 BYTES
$0580
↓
$05FF
ROM-2, 128 BYTES
$0600
↓
$07FF
EEPROM-2, 512 BYTES
$0800
↓
$09FF
EEPROM-1, 512 BYTES
$0A00
↓
$0DFF
RAM-2 , 1024 BYTES
$0E00
↓
$7FFF
ROM-2, 29,184 BYTES
$8000
↓
$FDFF
ROM-1, 32,256 BYTES
$FE00
SIM BREAK STATUS REGISTER (SBSR)
$FE01
SIM RESET STATUS REGISTER (SRSR)
$FE02
RESERVED
$FE03
SIM BREAK FLAG CONTROL REGISTER (SBFCR)
Technical Data
42
MC68HC08AZ60A — Rev 2.1
Memory Map
Freescale Semiconductor
Memory Map
MC68HC08AZ60A
$FE04
↓
$FE08
RESERVED (5 BYTES)
$FE09
MASK OPTION REGISTER B (MORB)
$FE0A
RESERVED
$FE0B
RESERVED
$FE0C
BREAK ADDRESS REGISTER HIGH (BRKH)
$FE0D
BREAK ADDRESS REGISTER LOW (BRKL)
$FE0E
BREAK STATUS AND CONTROL REGISTER (BSCR)
$FE0F
LVI STATUS REGISTER (LVISR)
$FE10
EEPROM-1EEDIVH NON-VOLATILE REGISTER (EE1DIVHNVR)
$FE11
EEPROM-1EEDIVL NON-VOLATILE REGISTER (EE1DIVLNVR)
$FE12
↓
$FE19
RESERVED (8 BYTES)
$FE1A
EEPROM-1 EE DIVIDER HIGH REGISTER (EE1DIVH)
$FE1B
EEPROM-1 EE DIVIDER LOW REGISTER (EE1DIVL)
$FE1C
EEPROM-1 EEPROM NON-VOLATILE REGISTER (EE1NVR)
$FE1D
EEPROM-1 EEPROM CONTROL REGISTER (EE1CR)
$FE1E
RESERVED
$FE1F
EEPROM-1 EEPROM ARRAY CONFIGURATION REGISTER (EE1ACR)
$FE20
↓
$FF1F
MONITOR ROM (256 BYTES)
$FF20
↓
$FF6F
UNIMPLEMENTED (80 BYTES)
$FF70
EEPROM-2 EEDIVH NON-VOLATILE REGISTER (EE2DIVHNVR)
$FF71
EEPROM-2 EEDIVL NON-VOLATILE REGISTER (EE2DIVLNVR)
$FF72
↓
$FF79
RESERVED (8 BYTES)
$FF7A
EEPROM-2 EE DIVIDER HIGH REGISTER (EE2DIVH)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Memory Map
43
Memory Map
MC68HC08AZ60A
$FF7B
EEPROM-2 EE DIVIDER LOW REGISTER (EE2DIVL)
$FF7C
EEPROM-2 EEPROM NON-VOLATILE REGISTER (EE2NVR)
$FF7D
EEPROM-2 EEPROM CONTROL REGISTER (EE2CR)
$FF7E
RESERVED
$FF7F
EEPROM-2 EEPROM ARRAY CONFIGURATION REGISTER (EE2ACR)
$FF80
↓
$FFCB
RESERVED (76 BYTES)
$FFCC
↓
$FFFF
VECTORS (52 BYTES)
See Table 2-1 on page 52
Figure 2-1. Memory Map (Continued)
Technical Data
44
MC68HC08AZ60A — Rev 2.1
Memory Map
Freescale Semiconductor
Memory Map
2.3 I/O Section
Addresses $0000–$004F, shown in Figure 2-2, contain the I/O Data,
Status and Control Registers.
Addr.
Register Name
$0000
Port A Data Register (PTA)
$0001
Port B Data Register (PTB)
$0002
Port C Data Register (PTC)
$0003
Port D Data Register (PTD)
Read:
Write:
Read:
Write:
Read:
Bit 7
6
5
4
3
2
1
Bit 0
PTA7
PTA6
PTA5
PTA4
PTA3
PTA2
PTA1
PTA0
PTB7
PTB6
PTB5
PTB4
PTB3
PTB2
PTB1
PTB0
0
0
PTC5
PTC4
PTC3
PTC2
PTC1
PTC0
PTD7
PTD6
PTD5
PTD4
PTD3
PTD2
PTD1
PTD0
Write:
Read:
Write:
$0004
Data Direction Register A Read:
DDRA7
(DDRA) Write:
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
DDRA1
DDRA0
$0005
Data Direction Register B Read:
DDRB7
(DDRB) Write:
DDRB6
DDRB5
DDRB4
DDRB3
DDRB2
DDRB1
DDRB0
$0006
Data Direction Register C Read: MCLKE
(DDRC) Write:
N
DDRC5
DDRC4
DDRC3
DDRC2
DDRC1
DDRC0
$0007
Data Direction Register D Read:
DDRD7
(DDRD) Write:
DDRD6
DDRD5
DDRD4
DDRD3
DDR2
DDRD1
DDRD0
PTE6
PTE5
PTE4
PTE3
PTE2
PTE1
PTE0
PTF6
PTF5
PTF4
PTF3
PTF2
PTF1
PTF0
0
0
0
0
0
PTG2
PTG1
PTG0
0
0
0
0
0
0
PTH1
PTH0
$0008
Port E Data Register (PTE)
$0009
Port F Data Register (PTF)
$000A
Port G Data Register (PTG)
$000B
Port H Data Register (PTH)
Read:
Write:
Read:
PTE7
0
Write:
Read:
0
Write:
Read:
Write:
$000C
Data Direction Register E Read:
DDRE7
(DDRE) Write:
DDRE6
DDRE5
DDRE4
DDRE3
DDRE2
DDRE1
DDRE0
$000D
Data Direction Register F Read:
(DDRF) Write:
0
DDRF6
DDRF5
DDRF4
DDRF3
DDRF2
DDRF1
DDRF0
$000E
Data Direction Register G Read:
(DDRG) Write:
0
0
0
0
0
DDRG2
DDRG1
DDRG0
$000F
Data Direction Register H Read:
(DDRH) Write:
0
0
0
0
0
DDRH1
DDRH0
0
Figure 2-2. I/O Data, Status and Control Registers (Sheet 1 of 5)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Memory Map
45
Memory Map
Addr.
$0010
Register Name
SPI Control Register (SPCR)
Read:
Write:
SPI Status and Control Read:
Register (SPSCR) Write:
$0011
$0012
SPI Data Register (SPDR)
$0013
SCI Control Register 1 (SCC1)
$0014
SCI Control Register 2 (SCC2)
$0015
SCI Control Register 3 (SCC3)
$0016
SCI Status Register 1 (SCS1)
$0017
SCI Status Register 2 (SCS2)
$0018
SCI Data Register (SCDR)
$0019
SCI Baud Rate Register (SCBR)
Bit 7
6
5
4
3
2
1
Bit 0
SPRIE
R
SPMSTR
CPOL
CPHA
SPWOM
SPE
SPTIE
OVRF
MODF
SPTE
MODFE
N
SPR1
SPR0
SPRF
Read:
R7
R6
R5
R4
R3
R2
R1
R0
Write:
T7
T6
T5
T4
T3
T2
T1
T0
LOOPS
ENSCI
TXINV
M
WAKE
ILTY
PEN
PTY
SCTIE
TCIE
SCRIE
ILIE
TE
RE
RWU
SBK
T8
R
R
ORIE
NEIE
FEIE
PEIE
SCTE
TC
SCRF
IDLE
OR
NF
FE
PE
0
0
0
0
0
0
BKF
RPF
Read:
R7
R6
R5
R4
R3
R2
R1
R0
Write:
T7
T6
T5
T4
T3
T2
T1
T0
Read:
0
0
SCP1
SCP0
R
SCR2
SCR1
SCR0
0
0
0
IRQF
0
IMASK
MODE
Read:
Write:
Read:
Write:
Read:
R8
Write:
Read:
Write:
Read:
Write:
Write:
$001A
IRQ Status and Control Read:
Register (ISCR) Write:
0
$001B
Keyboard Status and Control Read:
Register (KBSCR) Write:
0
$001C
PLL Control Register (PCTL)
Read:
Write:
ACK
PLLIE
PLL Bandwidth Control Read:
Register (PBWC) Write:
AUTO
$001E
PLL Programming Register Read:
(PPG) Write:
MUL7
Mask Option Register A (MORA)
0
0
0
KEYF
0
ACKK
$001D
$001F
ERRIE
PLLF
LOCK
MUL6
PLLON
BCS
ACQ
XLD
MUL5
MUL4
IMASKK MODEK
1
1
1
1
0
0
0
0
VRS7
VRS6
VRS5
VRS4
COPRS
STOP
COPD
PS2
PS1
PS0
KBIE2
KBIE1
KBIE0
Read: LVISTOP ROMSEC LVIRST LVIPWR SSREC
Write:
$0020
Timer A Status and Control Read:
Register (TASC) Write:
TOF
$0021
Keyboard Interrupt Enable Read:
Register (KBIER) Write:
0
0
TOIE
TSTOP
0
0
0
0
TRST
R
KBIE4
KBIE3
Figure 2-2. I/O Data, Status and Control Registers (Sheet 2 of 5)
Technical Data
46
MC68HC08AZ60A — Rev 2.1
Memory Map
Freescale Semiconductor
Memory Map
Addr.
Register Name
Bit 7
6
5
4
3
2
1
Bit 0
$0022
Timer A Counter Register Read:
High (TACNTH) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0023
Timer A Counter Register Read:
Low (TACNTL) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$0024
Timer A Modulo Register Read:
High (TAMODH) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0025
Timer A Modulo Register Read:
Low (TAMODL) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$0026
Timer A Channel 0 Status and Read:
Control Register (TASC0) Write:
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
$0027
Timer A Channel 0 Register Read:
High (TACH0H) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0028
Timer A Channel 0 Register Read:
Low (TACH0L) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$0029
Timer A Channel 1 Status and Read:
Control Register (TASC1) Write:
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
$002A
Timer A Channel 1 Register Read:
High (TACH1H) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$002B
Timer A Channel 1 Register Read:
Low (TACH1L) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$002C
Timer A Channel 2 Status and Read:
Control Register (TASC2) Write:
CH2IE
MS2B
MS2A
ELS2B
ELS2A
TOV2
CH2MAX
$002D
Timer A Channel 2 Register Read:
High (TACH2H) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$002E
Timer A Channel 2 Register Read:
Low (TACH2L) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$002F
Timer A Channel 3 Status and Read:
Control Register (TASC3) Write:
MS3A
ELS3B
ELS3A
TOV3
CH3MAX
$0030
Timer A Channel 3 Register Read:
High (TACH3H) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0031
Timer A Channel 3 Register Read:
Low (TACH3L) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$0032
Timer A Channel 4 Status and Read:
Control Register (TASC4) Write:
CH4IE
MS4B
MS4A
ELS4B
ELS4A
TOV4
CH4MAX
$0033
Timer A Channel 4 Register High Read:
(TACH4H) Write:
14
13
12
11
10
9
Bit 8
CH0F
0
CH1F
0
CH2F
0
CH3F
0
CH4F
0
Bit 15
0
CH1IE
R
0
CH3IE
R
Figure 2-2. I/O Data, Status and Control Registers (Sheet 3 of 5)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Memory Map
47
Memory Map
Addr.
Register Name
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
MS5A
ELS5B
ELS5A
TOV5
CH5MAX
$0034
Timer A Channel 4 Register Low Read:
(TACH4L) Write:
$0035
Timer A Channel 5 Status and Read:
Control Register (TASC5) Write:
$0036
Timer A Channel 5 Register Read:
High (TACH5H) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0037
Timer A Channel 5 Register Read:
Low (TACH5L) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$0038
Analog-to-Digital Status and Read:
Control Register (ADSCR) Write:
AIEN
ADCO
ADCH4
ADCH3
ADCH2
ADCH1
ADCH0
$0039
Analog-to-Digital Data Register Read:
(ADR) Write:
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
R
R
R
R
R
R
R
R
$003A
Analog-to-Digital Input Clock Read:
Register (ADICLK) Write:
ADIV2
ADIV1
ADIV0
ADICLK
0
0
0
0
R
R
R
R
TOIE
TSTOP
PS2
PS1
PS0
$003B
Unimplemented
$003C
Unimplemented
$003D
Unimplemented
$003E
Unimplemented
$003F
Unimplemented
CH5F
0
COCO
R
0
CH5IE
R
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
$0040
Timer B Status and Control Read:
Register (TBSCR) Write:
TOF
0
0
TRST
R
$0041
Timer B Counter Register High Read:
(TBCNTH) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0042
Timer B Counter Register Low Read:
(TBCNTL) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$0043
Timer B Modulo Register High Read:
(TBMODH) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0044
Timer B Modulo Register Low Read:
(TBMODL) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$0045
Timer B CH0 Status and Control Read:
Register (TBSC0) Write:
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
0
CH0F
0
Figure 2-2. I/O Data, Status and Control Registers (Sheet 4 of 5)
Technical Data
48
MC68HC08AZ60A — Rev 2.1
Memory Map
Freescale Semiconductor
Memory Map
Addr.
Register Name
Bit 7
6
5
4
3
2
1
Bit 0
$0046
Timer B CH0 Register High Read:
(TBCH0H) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$0047
Timer B CH0 Register Low Read:
(TBCH0L) Write:
Bit 7
6
5
4
3
2
1
Bit 0
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
$0048
Timer B CH1 Status and Control Read:
Register (TBSC1) Write:
CH1F
0
0
CH1IE
R
$0049
Timer B CH1 Register High Read:
(TBCH1H) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$004A
Timer B CH1 Register Low Read:
(TBCH1L) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$004B
PIT Status and Control Register Read:
(PSC) Write:
POF
POIE
PSTOP
0
0
PPS2
PPS1
PPS0
$004C
PIT Counter Register High Read:
(PCNTH) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$004D
PIT Counter Register Low Read:
(PCNTL) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$004E
PIT Modulo Register High Read:
(PMODH) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$004F
PIT Modulo Register Low Read:
(PMODL) Write:
Bit 7
6
5
4
3
2
1
Bit 0
0
= Unimplemented
PRST
R
= Reserved
Figure 2-2. I/O Data, Status and Control Registers (Sheet 5 of 5)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Memory Map
49
Memory Map
2.4 Additional Status and Control Registers
Selected addresses in the range $FE00 to $FFCB contain additional
Status and Control registers as shown in Figure 2-3. A noted exception
is the COP Control Register (COPCTL) at address $FFFF.
Addr.
Register Name
$FE00
SIM Break Status Register Read:
(SBSR) Write:
$FE01 SIM Reset Status Register (SRSR)
$FE03
$FE09
Read:
6
5
4
3
2
1
R
R
R
R
R
R
POR
PIN
COP
ILOP
ILAD
0
LVI
0
BCFE
R
R
R
R
R
R
R
0
0
0
BW
0
Bit 0
R
Write:
SIM Break Flag Control Register Read:
(SBFCR) Write:
Mask Options Register B (MORB)
Bit 7
Read: EEDIVCLK
0
EESEC EEMONSEC AZ60A
Write:
$FE0C
Break Address Register High Read:
(BRKH) Write:
Bit 15
14
13
12
11
10
9
Bit 8
$FE0D
Break Address Register Low Read:
(BRKL) Write:
Bit 7
6
5
4
3
2
1
Bit 0
$FE0E
Break Status and Control Read:
Register (BRKSCR) Write:
BRKE
BRKA
0
0
0
0
0
0
0
0
0
0
0
0
0
R
R
R
R
EEDIV6
EEDIV5
EEDIV4
EEDIV3
0
0
0
0
EEDIV6
EEDIV5
EEDIV4
$FE0F
LVI Status Register (LVISR)
Read: LVIOUT
Write:
$FE10
EE1DIV Hi Non-volatile Register Read:
EEDIVSECD
(EE1DIVHNVR) Write:
$FE11
EE1DIV Lo Non-volatile Register Read:
EEDIV7
(EE1DIVLNVR) Write:
EEDIV10 EEDIV9
EEDIV8
EEDIV2
EEDIV1
EEDIV0
EEDIV10 EEDIV9
EEDIV8
EEDIV3
EEDIV2
EEDIV1
EEDIV0
EEPROM-1 Nonvolatile Register Read:
UNUSED UNUSED UNUSED EEPRTCT EEBP3
(EE1NVR) Write:
EEBP2
EEBP1
EEBP0
EELAT
AUTO
EEPGM
EEBP2
EEBP1
EEBP0
$FE1A
EE1DIV Divider High Register Read:
EEDIVSECD
(EE1DIVH) Write:
$FE1B
EE1DIV Divider Low Register Read:
EEDIV7
(EE1DIVL) Write:
$FE1C
$FE1D
$FE1F
EEPROM-1 Control Register Read:
UNUSED
(EE1CR) Write:
0
EEOFF EERAS1 EERAS0
EEPROM-1 Array Configuration Read: UNUSED UNUSED UNUSED EEPRTCT EEBP3
Register (EE1ACR) Write:
Figure 2-3. Additional Status and Control Registers (Sheet 1 of 2)
Technical Data
50
MC68HC08AZ60A — Rev 2.1
Memory Map
Freescale Semiconductor
Memory Map
Addr.
Register Name
Bit 7
$FF70
EE2DIV Hi Non-volatile Register Read:
EEDIVSECD
(EE2DIVHNVR)
$FF71
EE2DIV Lo Non-volatile Register Read:
$FE7D
$FE7F
$FFFF
3
R
R
R
R
EEDIV6
EEDIV5
EEDIV4
EEDIV3
0
0
0
0
EEDIV6
EEDIV5
EEDIV4
2
1
Bit 0
EEDIV2
EEDIV1
EEDIV0
EEDIV10 EEDIV9
EEDIV8
EEDIV3
EEDIV2
EEDIV1
EEDIV0
EEPROM-2 Nonvolatile Register Read:
UNUSED UNUSED UNUSED EEPRTCT EEBP3
(EE2NVR) Write:
EEBP2
EEBP1
EEBP0
EELAT
AUTO
EEPGM
EEBP2
EEBP1
EEBP0
EE2DIV Divider High Register Read:
EE2DIV Divider Low Register Read:
(EE2DIVL)
$FE7C
4
EEDIV8
(EE2DIVH)
$FF7B
5
EEDIV10 EEDIV9
(EE2DIVLNVR)
$FF7A
6
EEDIV7
EEDIVSECD
EEDIV7
EEPROM-2 Control Register Read:
UNUSED
(EE2CR) Write:
0
EEOFF EERAS1 EERAS0
EEPROM-2 Array Configuration Read: UNUSED UNUSED UNUSED EEPRTCT EEBP3
Register (EE2ACR) Write:
COP Control Register (COPCTL)
Read:
LOW BYTE OF RESET VECTOR
Write:
WRITING TO $FFFF CLEARS COP COUNTER
= Unimplemented
R
= Reserved
Figure 2-3. Additional Status and Control Registers (Sheet 2 of 2)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Memory Map
51
Memory Map
2.5 Vector Addresses and Priority
Addresses in the range $FFCC to $FFFF contain the user-specified
vector locations. The vector addresses are shown inTable 2-1.
Table 2-1. Vector addresses (1)
Address
Priority
Lowest Priority
TIMA Channel 5 Vector (high)
$FFCD
TIMA Channel 5 Vector (low)
$FFCE
TIMA Channel 4 Vector (high)
$FFCF
TIMA Channel 4 Vector (low)
$FFD0
ADC Vector (high)
$FFD1
ADC Vector (low)
$FFD2
Keyboard Vector (high)
$FFD3
Keyboard Vector (low)
$FFD4
SCI Transmit Vector (high)
$FFD5
SCI Transmit Vector (Low)
$FFD6
SCI Receive Vector (High)
$FFD7
SCI Receive Vector (Low)
$FFD8
SCI Error Vector (High)
$FFD9
SCI Error Vector (Low)
$FFDA
MSCAN08 Transmit Vector (High)
$FFDB
MSCAN08 Transmit Vector (Low)
$FFDC
MSCAN08 Receive Vector (High)
$FFDD
MSCAN08 Receive Vector (Low)
$FFDE
MSCAN08 Error Vector (High)
$FFDF
MSCAN08 Error Vector (Low)
$FFE0
MSCAN08 Wakeup Vector (High)
$FFE1
MSCAN08 Wakeup Vector (Low)
Technical Data
52
Vector
$FFCC
MC68HC08AZ60A — Rev 2.1
Memory Map
Freescale Semiconductor
Memory Map
Table 2-1. Vector addresses (Continued)(1)
Address
Priority
$FFE2
Highest Priority
Vector
SPI Transmit Vector (High)
$FFE3
SPI Transmit Vector (Low)
$FFE4
SPI Receive Vector (High)
$FFE5
SPI Receive Vector (Low)
$FFE6
TIMB Overflow Vector (High)
$FFE7
TIMB Overflow Vector (Low)
$FFE8
TIMB CH1 Vector (High)
$FFE9
TIMB CH1 Vector (Low)
$FFEA
TIMB CH0 Vector (High)
$FFEB
TIMB CH0 Vector (Low)
$FFEC
TIMA Overflow Vector (High)
$FFED
TIMA Overflow Vector (Low)
$FFEE
TIMA CH3 Vector (High)
$FFEF
TIMA CH3 Vector (Low)
$FFF0
TIMA CH2 Vector (High)
$FFF1
TIMA CH2 Vector (Low)
$FFF2
TIMA CH1 Vector (High)
$FFF3
TIMA CH1 Vector (Low)
$FFF4
TIMA CH0 Vector (High)
$FFF5
TIMA CH0 Vector (Low)
$FFF6
PIT Vector (High)
$FFF7
PIT Vector (Low)
$FFF8
PLL Vector (High)
$FFF9
PLL Vector (Low)
$FFFA
IRQ Vector (High)
$FFFB
IRQ Vector (Low)
$FFFC
SWI Vector (High)
$FFFD
SWI Vector (Low)
$FFFE
Reset Vector (High)
$FFFF
Reset Vector (Low)
1. All available ROM locations not defined by the user will by
default be filled with the software interrupt (SWI, opcode 83)
instruction – see Central Processor Unit (CPU). Take this into
account when defining vector addresses. It is recommended that
ALL vector addresses are defined.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Memory Map
53
Memory Map
Technical Data
54
MC68HC08AZ60A — Rev 2.1
Memory Map
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 3. RAM
3.1 Contents
3.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.3
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.2 Introduction
This section describes the 2048 bytes of random-access memory
(RAM).
3.3 Functional Description
Addresses $0050 through $044F and $0A00 through $0DFF are RAM
locations. The location of the stack RAM is programmable with the reset
stack pointer instruction (RSP). The 16-bit stack pointer allows the stack
RAM to be anywhere in the 64K-byte memory space.
NOTE:
For correct operation, the stack pointer must point only to RAM
locations.
Within page zero are 176 bytes of RAM. Because the location of the
stack RAM is programmable, all page zero RAM locations can be used
for input/output (I/O) control and user data or code. When the stack
pointer is moved from its reset location at $00FF, direct addressing
mode instructions can access all page zero RAM locations efficiently.
Page zero RAM, therefore, provides ideal locations for frequently
accessed global variables.
Before processing an interrupt, the CPU uses five bytes of the stack to
save the contents of the CPU registers.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
RAM
55
RAM
NOTE:
For M68HC05, M6805, and M146805 compatibility, the H register is not
stacked.
During a subroutine call, the CPU uses two bytes of the stack to store
the return address. The stack pointer decrements during pushes and
increments during pulls.
NOTE:
Be careful when using nested subroutines. The CPU could overwrite
data in the RAM during a subroutine or during the interrupt stacking
operation.
Technical Data
56
MC68HC08AZ60A — Rev 2.1
RAM
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 4. ROM
4.1 Contents
4.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.3
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.4
Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.2 Introduction
This section describes the operation of the embedded ROM memory.
4.3 Functional Description
The user ROM consists of up to 61,744 bytes located in address ranges
$0450–-$04FF, $0580–-$05FF and $0E00–$FDFF. The monitor ROM
and vectors are located from $FE20–$FF5F.
Fifty-two user vectors, $FFCC–$FFFF, are dedicated to user-defined
reset and interrupt vectors.
4.4 Security
Security has been incorporated into the MC68HC08AZ60A to prevent
external viewing of the ROM contents(1). This feature is selected by a
mask option and ensures that customer-developed software remains
proprietary. See Mask Options on page 167.
1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or
copying the ROM difficult for unauthorized users.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
ROM
57
ROM
Technical Data
58
MC68HC08AZ60A — Rev 2.1
ROM
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 5. EEPROM-1
5.1 Contents
5.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
5.4
EEPROM-1 Register Summary . . . . . . . . . . . . . . . . . . . . . . . 61
5.5
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.5.1
EEPROM-1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.5.2
EEPROM-1 Timebase Requirements . . . . . . . . . . . . . . . . 62
5.5.3
EEPROM-1 Program/Erase Protection . . . . . . . . . . . . . . . 63
5.5.4
EEPROM-1 Block Protection . . . . . . . . . . . . . . . . . . . . . . . 64
5.5.5
EEPROM-1 Programming and Erasing. . . . . . . . . . . . . . . 64
5.6
EEPROM-1 Register Descriptions. . . . . . . . . . . . . . . . . . . . .69
5.6.1
EEPROM-1 Control Register . . . . . . . . . . . . . . . . . . . . . . . 69
5.6.2
EEPROM-1 Array Configuration Register . . . . . . . . . . . . 71
5.6.3
EEPROM-1 Nonvolatile Register. . . . . . . . . . . . . . . . . . . . 73
5.6.4
EEPROM-1 Timebase Divider Register . . . . . . . . . . . . . . 74
5.6.5
EEPROM-1 Timebase Divider Non-Volatile Register . . . 76
5.7
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.7.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.7.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.2 Introduction
This section describes the 512 bytes of electrically erasable
programmable read-only memory (EEPROM) residing at address range
$0800 to $09FF. There are 1024 bytes of EEPROM available on the
MC68HC08AZ60A which are physically located in two 512 byte arrays.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-1
59
EEPROM-1
For information relating to the array covering address range $0600 to
$07FF please see EEPROM-2 on page 79.
5.3 Features
Features of the EEPROM-1 include the following:
•
512 bytes Non-Volatile Memory
•
Byte, Block, or Bulk Erasable
•
Non-Volatile EEPROM-1 Configuration and Block Protection
Options
•
On-Chip Charge Pump for Programming/Erasing
•
Program/Erase Protection Option
•
Read Protection Option (in Monitor Mode)
•
AUTO Bit Driven Programming/Erasing Time Feature
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EEPROM-1
5.4 EEPROM-1 Register Summary
The EEPROM-1 Register Summary is shown in Figure 5-1.
Addr.
$FE10
$FE11
Register Name
Bit 7
Read:
EE1DIV Non-volatile
EEDIVSECD
Register High Write:
(EE1DIVHNVR)*
Reset:
Read:
EE1DIV Non-volatile
EEDIV7
Register Low Write:
(EE1DIVLNVR)*
Reset:
Read:
EEDIVSECD
EE1 Divider Register High
$FE1A
Write:
(EE1DIVH)
Reset:
Read:
EEDIV7
EE1 Divider Register Low
Write:
$FE1B
(EE1DIVL)
Reset:
$FE1C
$FE1D
$FE1F
6
5
4
3
2
1
Bit 0
R
R
R
R
EEDIV10
EEDIV9
EEDIV8
EEDIV1
EEDIV0
EEDIV9
EEDIV8
EEDIV1
EEDIV0
Unaffected by reset; $FF when blank
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
Unaffected by reset; $FF when blank
0
0
0
0
EEDIV10
Contents of EE1DIVHNVR ($FE10), Bits [6:3] = 0
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
Contents of EE1DIVLNVR ($FE11)
Read:
EEPROM-1 Non-volatile
UNUSED UNUSED UNUSED EEPRTCT EEBP3
EEBP2
EEBP1
Register Write:
(EE1NVR)*
Reset:
Unaffected by reset; $FF when blank; factory programmed $F0
Read:
EEPROM-1 Control
UNUSED
Register Write:
(EE1CR)
Reset:
0
0
0
EEBP0
EEOFF
EERAS1
EERAS0
EELAT
AUTO
EEPGM
0
0
0
0
0
0
EEBP1
EEBP0
Read: UNUSED UNUSED UNUSED EEPRTCT EEBP3
EEBP2
EEPROM-1 Array
Configuration Register Write:
(EE1ACR)
Reset:
Contents of EE1NVR ($FE1C)
* Non-volatile EEPROM register; write by programming.
= Unimplemented
R
= Reserved
UNUSED = Unused
Figure 5-1. EEPROM-1 Register Summary
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-1
61
EEPROM-1
5.5 Functional Description
The 512 bytes of EEPROM-1 are located at $0800-$09FF and can be
programmed or erased without an additional external high voltage
supply. The program and erase operations are enabled through the use
of an internal charge pump. For each byte of EEPROM, the write/erase
endurance is 10,000 cycles.
5.5.1 EEPROM-1 Configuration
The 8-bit EEPROM-1 Non-Volatile Register (EE1NVR) and the 16-bit
EEPROM-1 Timebase Divider Non-Volatile Register (EE1DIVNVR)
contain the default settings for the following EEPROM-1 configurations:
•
EEPROM-1 Timebase Reference
•
EEPROM-1 Program/Erase Protection
•
EEPROM-1 Block Protection
EE1NVR and EE1DIVNVR are non-volatile EEPROM registers. They
are programmed and erased in the same way as EEPROM bytes. The
contents of these registers are loaded into their respective volatile
registers during a MCU reset. The values in these read/write volatile
registers define the EEPROM-1 configurations.
For EE1NVR, the corresponding volatile register is the EEPROM-1
Array Configuration Register (EEACR). For the EE1DIVNVR (two 8-bit
registers: EE1DIVHNVR and EE1DIVLNVR), the corresponding volatile
register is the EEPROM-1 Divider Register (EE1DIV: EE1DIVH and
EE1DIVL).
5.5.2 EEPROM-1 Timebase Requirements
A 35µs timebase is required by the EEPROM-1 control circuit for
program and erase of EEPROM-1 content. This timebase is derived
from dividing the CGMXCLK or bus clock (selected by EEDIVCLK bit in
Mask Option Register B) using a timebase divider circuit controlled by
the 16-bit EEPROM-1 Timebase Divider EE1DIV Register (EE1DIVH
and EE1DIVL).
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EEPROM-1
As the CGMXCLK or bus clock is user selected, the EEPROM-1
Timebase Divider Register must be configured with the appropriate
value to obtain the 35 µs. The timebase divider value is calculated by
using the following formula:
EE1DIV= INT[Reference Frequency(Hz) x 35 x10-6 +0.5]
This value is written to the EEPROM-1 Timebase Divider Register
(EE1DIVH and EE1DIVL) or programmed into the EEPROM-1
Timebase Divider Non-Volatile Register prior to any EEPROM-1
program or erase operations(see EEPROM-1 Configuration on page
62 and EEPROM-1 Timebase Requirements on page 62).
5.5.3 EEPROM-1 Program/Erase Protection
The EEPROM-1 has a special feature that designates the 16 bytes of
addresses from $08F0 to $08FF to be permanently secured. This
program/erase protect option is enabled by programming the EEPRTCT
bit in the EEPROM-1 Non-Volatile Register (EE1NVR) to a logic zero.
Once the EEPRTCT bit is programmed to 0 for the first time:
NOTE:
•
Programming and erasing of secured locations $08F0 to $08FF is
permanently disabled.
•
Secured locations $08F0 to $08FF can be read as normal.
•
Programming and erasing of EE1NVR is permanently disabled.
•
Bulk and Block Erase operations are disabled for the unprotected
locations $0800-$08EF, $0900-$09FF.
•
Single byte program and erase operations are still available for
locations $0800-$08EF and $0900-$09FF for all bytes that are not
protected by the EEPROM-1 Block Protect EEBPx bits (see
EEPROM-1 Block Protection on page 64 and EEPROM-1 Array
Configuration Register on page 71).
Once armed, the protect option is permanently enabled. As a
consequence, all functions in the EE1NVR will remain in the state they
were in immediately before the security was enabled.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-1
63
EEPROM-1
5.5.4 EEPROM-1 Block Protection
The 512 bytes of EEPROM-1 are divided into four 128-byte blocks. Each
of these blocks can be protected from erase/program operations by
setting the EEBPx bit in the EE1NVR. Table 5-1 shows the address
ranges for the blocks.
Table 5-1. EEPROM-1 Array Address Blocks
Block Number (EEBPx)
Address Range
EEBP0
$0800–$087F
EEBP1
$0880–$08FF
EEBP2
$0900–$097F
EEBP3
$0980–$09FF
These bits are effective after a reset or a upon read of the EE1NVR
register. The block protect configuration can be modified by
erasing/programming the corresponding bits in the EE1NVR register
and then reading the EE1NVR register. Please see EEPROM-1 Array
Configuration Register on page 71 for more information.
NOTE:
Once EEDIVSECD in the EE1DIVHNVR is programmed to 0 and after a
system reset, the EE1DIV security feature is permanently enabled
because the EEDIVSECD bit in the EE1DIVH is always loaded with 0
thereafter. Once this security feature is armed, erase and program mode
are disabled for EE1DIVHNVR and EE1DIVLNVR. Modifications to the
EE1DIVH and EE1DIVL registers are also disabled. Therefore, be
cautious on programming a value into the EE1DIVHNVR.
5.5.5 EEPROM-1 Programming and Erasing
The unprogrammed or erase state of an EEPROM-1 bit is a logic 1. The
factory default for all bytes within the EEPROM-1 array is $FF.
The programming operation changes an EEPROM-1 bit from logic 1 to
logic 0 (programming cannot change a bit from logic 0 to a logic 1). In a
single programming operation, the minimum EEPROM-1 programming
size is one bit; the maximum is eight bits (one byte).
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Freescale Semiconductor
EEPROM-1
The erase operation changes an EEPROM-1 bit from logic 0 to logic 1.
In a single erase operation, the minimum EEPROM-1 erase size is one
byte; the maximum is the entire EEPROM-1 array.
The EEPROM-1 can be programmed such that one or multiple bits are
programmed (written to a logic 0) at a time. However, the user may never
program the same bit location more than once before erasing the entire
byte. In other words, the user is not allowed to program a logic 0 to a bit
that is already programmed (bit state is already logic 0).
For some applications it might be advantageous to track more than 10K
events with a single byte of EEPROM-1 by programming one bit at a
time. For that purpose, a special selective bit programming technique is
available. An example of this technique is illustrated in Table 5-2.
Table 5-2. Example Selective Bit Programming Description
Program Data
in Binary
Result
in Binary
n/a
1111:1111
First event is recorded by programming bit position 0
1111:1110
1111:1110
Second event is recorded by programming bit position 1
1111:1101
1111:1100
Third event is recorded by programming bit position 2
1111:1011
1111:1000
Fourth event is recorded by programming bit position 3
1111:0111
1111:0000
Description
Original state of byte (erased)
Events five through eight are recorded in a similar fashion
Note that none of the bit locations are actually programmed more than
once although the byte was programmed eight times.
When this technique is utilized, a program/erase cycle is defined as
multiple program sequences (up to eight) to a unique location followed
by a single erase operation.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-1
65
EEPROM-1
5.5.5.1 Program/Erase Using AUTO Bit
An additional feature available for EEPROM-1 program and erase
operations is the AUTO mode. When enabled, AUTO mode will activate
an internal timer that will automatically terminate the program/erase
cycle and clear the EEPGM bit. Please see EEPROM-1 Programming
on page 66, EEPROM-1 Erasing on page 67 and EEPROM-1 Control
Register on page 69 for more information.
5.5.5.2 EEPROM-1 Programming
The unprogrammed or erase state of an EEPROM-1 bit is a logic 1.
Programming changes the state to a logic 0. Only EEPROM-1 bytes in
the non-protected blocks and the EE1NVR register can be programmed.
Use the following procedure to program a byte of EEPROM-1:
1. Clear EERAS1 and EERAS0 and set EELAT in the EE1CR.(A)
NOTE:
If using the AUTO mode, also set the AUTO bit during Step 1.
2. Write the desired data to the desired EEPROM-1 address.(B)
3. Set the EEPGM bit.(C) Go to Step 7 if AUTO is set.
4. Wait for time, tEEPGM, to program the byte.
5. Clear EEPGM bit.
6. Wait for time, tEEFPV, for the programming voltage to fall. Go to
Step 8.
7. Poll the EEPGM bit until it is cleared by the internal timer.(D)
8. Clear EELAT bits.(E)
NOTE:
A. EERAS1 and EERAS0 must be cleared for programming. Setting the
EELAT bit configures the address and data buses to latch data for
programming the array. Only data with a valid EEPROM-1 address will
be latched. If EELAT is set, other writes to the EE1CR will be allowed
after a valid EEPROM-1 write.
B. If more than one valid EEPROM-1 write occurs, the last address and
data will be latched overriding the previous address and data. Once data
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EEPROM-1
is written to the desired address, do not read EEPROM-1 locations other
than the written location. (Reading an EEPROM-1 location returns the
latched data and causes the read address to be latched).
C. The EEPGM bit cannot be set if the EELAT bit is cleared or a nonvalid EEPROM-1 address is latched. This is to ensure proper
programming sequence. Once EEPGM is set, do not read any
EEPROM-1 locations; otherwise, the current program cycle will be
unsuccessful. When EEPGM is set, the on-board programming
sequence will be activated.
D. The delay time for the EEPGM bit to be cleared in AUTO mode is less
than tEEPGM. However, on other MCUs, this delay time may be different.
For forward compatibility, software should not make any dependency on
this delay time.
E. Any attempt to clear both EEPGM and EELAT bits with a single
instruction will only clear EEPGM. This is to allow time for removal of
high voltage from the EEPROM-1 array.
5.5.5.3 EEPROM-1 Erasing
The programmed state of an EEPROM-1 bit is logic 0. Erasing changes
the state to a logic 1. Only EEPROM-1 bytes in the non-protected blocks
and the EE1NVR register can be erased.
Use the following procedure to erase a byte, block or the entire
EEPROM-1 array:
1. Configure EERAS1 and EERAS0 for byte, block or bulk erase; set
EELAT in EE1CR.(A)
NOTE:
If using the AUTO mode, also set the AUTO bit in Step 1.
2. Byte erase: write any data to the desired address.(B)
Block erase: write any data to an address within the desired
block.(B)
Bulk erase: write any data to an address within the array.(B)
3. Set the EEPGM bit.(C) Go to Step 7 if AUTO is set.
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Technical Data
EEPROM-1
67
EEPROM-1
4. Wait for a time: tEEBYTE for byte erase; tEEBLOCK for block erase;
tEEBULK. for bulk erase.
5. Clear EEPGM bit.
6. Wait for a time, tEEFPV, for the erasing voltage to fall. Go to Step 8.
7. Poll the EEPGM bit until it is cleared by the internal timer.(D)
8. Clear EELAT bits.(E)
NOTE:
A. Setting the EELAT bit configures the address and data buses to latch
data for erasing the array. Only valid EEPROM-1 addresses will be
latched. If EELAT is set, other writes to the EE1CR will be allowed after
a valid EEPROM-1 write.
B. If more than one valid EEPROM-1 write occurs, the last address and
data will be latched overriding the previous address and data. Once data
is written to the desired address, do not read EEPROM-1 locations other
than the written location. (Reading an EEPROM-1 location returns the
latched data and causes the read address to be latched).
C. The EEPGM bit cannot be set if the EELAT bit is cleared or a nonvalid EEPROM-1 address is latched. This is to ensure proper
programming sequence. Once EEPGM is set, do not read any
EEPROM-1 locations; otherwise, the current program cycle will be
unsuccessful. When EEPGM is set, the on-board programming
sequence will be activated.
D. The delay time for the EEPGM bit to be cleared in AUTO mode is less
than tEEBYTE /tEEBLOCK/tEEBULK. However, on other MCUs, this delay
time may be different. For forward compatibility, software should not
make any dependency on this delay time.
E. Any attempt to clear both EEPGM and EELAT bits with a single
instruction will only clear EEPGM. This is to allow time for removal of
high voltage from the EEPROM-1 array.
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EEPROM-1
5.6 EEPROM-1 Register Descriptions
Four I/O registers and three non-volatile registers control program, erase
and options of the EEPROM-1 array.
5.6.1 EEPROM-1 Control Register
This read/write register controls programming/erasing of the array.
Address:
$FE1D
Bit 7
Read:
Write:
Reset:
UNUSED
0
6
0
0
5
4
3
2
1
Bit 0
EEOFF
EERAS1
EERAS0
EELAT
AUTO
EEPGM
0
0
0
0
0
0
= Unimplemented
Figure 5-2. EEPROM-1 Control Register (EE1CR)
Bit 7— Unused bit
This read/write bit is software programmable but has no functionality.
EEOFF — EEPROM-1 Power Down
This read/write bit disables the EEPROM-1 module for lower power
consumption. Any attempts to access the array will give unpredictable
results. Reset clears this bit.
1 = Disable EEPROM-1 array
0 = Enable EEPROM-1 array
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-1
69
EEPROM-1
EERAS1 and EERAS0 — Erase/Program Mode Select Bits
These read/write bits set the erase modes. Reset clears these bits.
Table 5-3. EEPROM-1 Program/Erase Mode Select
EEBPx
EERAS1
EERAS0
MODE
0
0
0
Byte Program
0
0
1
Byte Erase
0
1
0
Block Erase
0
1
1
Bulk Erase
1
X
X
No Erase/Program
X = don’t care
EELAT — EEPROM-1 Latch Control
This read/write bit latches the address and data buses for
programming the EEPROM-1 array. EELAT cannot be cleared if
EEPGM is still set. Reset clears this bit.
1 = Buses configured for EEPROM-1 programming or erase
operation
0 = Buses configured for normal operation
AUTO — Automatic Termination of Program/Erase Cycle
When AUTO is set, EEPGM is cleared automatically after the
program/erase cycle is terminated by the internal timer.
(See note D for EEPROM-1 Programming on page 66, EEPROM-1
Erasing on page 67 and EEPROM Memory Characteristics on
page 456)
1 = Automatic clear of EEPGM is enabled
0 = Automatic clear of EEPGM is disabled
EEPGM — EEPROM-1 Program/Erase Enable
This read/write bit enables the internal charge pump and applies the
programming/erasing voltage to the EEPROM-1 array if the EELAT
bit is set and a write to a valid EEPROM-1 location has occurred.
Reset clears the EEPGM bit.
1 = EEPROM-1 programming/erasing power switched on
0 = EEPROM-1 programming/erasing power switched off
Technical Data
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EEPROM-1
Freescale Semiconductor
EEPROM-1
NOTE:
Writing logic 0s to both the EELAT and EEPGM bits with a single
instruction will clear EEPGM only to allow time for the removal of high
voltage.
5.6.2 EEPROM-1 Array Configuration Register
The EEPROM-1 array configuration register configures EEPROM-1
security and EEPROM-1 block protection.
This read-only register is loaded with the contents of the EEPROM-1
non-volatile register (EE1NVR) after a reset.
Address:
$FE1F
Bit 7
6
5
4
Read: UNUSED UNUSED UNUSED EEPRTCT
3
2
1
Bit 0
EEBP3
EEBP2
EEBP1
EEBP0
Write:
Reset:
Contents of EE1NVR ($FE1C)
Figure 5-3. EEPROM-1 Array Configuration Register (EE1ACR)
Bit 7:5 — Unused Bits
These read/write bits are software programmable but have no
functionality.
EEPRTCT — EEPROM-1 Protection Bit
The EEPRTCT bit is used to enable the security feature in the
EEPROM-1 (see EEPROM-1 Program/Erase Protection on page
63).
1 = EEPROM-1 security disabled
0 = EEPROM-1 security enabled
This feature is a write-once feature. Once the protection is enabled it
may not be disabled.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-1
71
EEPROM-1
EEBP[3:0] — EEPROM-1 Block Protection Bits
These bits prevent blocks of EEPROM-1 array from being
programmed or erased.
1 = EEPROM-1 array block is protected
0 = EEPROM-1 array block is unprotected
Block Number (EEBPx)
Address Range
EEBP0
$0800–$087F
EEBP1
$0880–$08FF
EEBP2
$0900–$097F
EEBP3
$0980–$09FF
Table 5-4. EEPROM-1 Block Protect and Security Summary
Address Range
EEBPx
EEPRTCT = 1
EEPRTCT = 0
EEBP0 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP0 = 1
Protected
Protected
EEBP1 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP1 = 1
Protected
Protected
EEBP1 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Secured
(No Programming
or Erasing)
EEBP1 = 1
Protected
EEBP2 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP2 = 1
Protected
Protected
$0800 - $087F
$0880 - $08EF
$08F0 - $08FF
$0900 - $097F
Technical Data
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MC68HC08AZ60A — Rev 2.1
EEPROM-1
Freescale Semiconductor
EEPROM-1
Table 5-4. EEPROM-1 Block Protect and Security Summary
Address Range
EEBPx
EEPRTCT = 1
EEPRTCT = 0
EEBP3 = 0
Byte Programming
Available
Bulk, Block and Byte
Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP3 = 1
Protected
Protected
$0980 - $09FF
5.6.3 EEPROM-1 Nonvolatile Register
The contents of this register is loaded into the EEPROM-1 array
configuration register (EE1ACR) after a reset.
This register is erased and programmed in the same way as an
EEPROM-1 byte. (See EEPROM-1 Control Register on page 69 for
individual bit descriptions).
Address:
$FE1C
Bit 7
Read:
Write:
6
5
4
UNUSED UNUSED UNUSED EEPRTCT
Reset:
3
2
1
Bit 0
EEBP3
EEBP2
EEBP1
EEBP0
PV
= Unimplemented
PV = Programmed value or 1 in the erased state.
Figure 5-4. EEPROM-1 Nonvolatile Register (EE1NVR)
NOTE:
The EE1NVR will leave the factory programmed with $F0 such that the
full array is available and unprotected.
MC68HC08AZ60A — Rev 2.1
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Technical Data
EEPROM-1
73
EEPROM-1
5.6.4 EEPROM-1 Timebase Divider Register
The 16-bit EEPROM-1 timebase divider register consists of two 8-bit
registers: EE1DIVH and EE1DIVL. The 11-bit value in this register is
used to configure the timebase divider circuit to obtain the 35 µs
timebase for EEPROM-1 control.
These two read/write registers are respectively loaded with the contents
of the EEPROM-1 timebase divider non-volatile registers
(EE1DIVHNVR and EE1DIVLNVR) after a reset.
Address:
$FE1A
Bit 7
Read:
Write:
EEDIVSECD
6
5
4
3
0
0
0
0
Reset:
2
1
Bit 0
EEDIV10
EEDIV9
EEDIV8
Contents of EE1DIVHNVR ($FE10), Bits [6:3] = 0
= Unimplemented
Figure 5-5. EE1DIV Divider High Register (EE1DIVH)
Address:
Read:
Write:
Reset:
$FE1B
Bit 7
6
5
4
3
2
1
Bit 0
EEDIV7
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
EEDIV1
EEDIV0
Contents of EE1DIVLNVR ($FE11)
Figure 5-6. EE1DIV Divider Low Register (EE1DIVL)
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MC68HC08AZ60A — Rev 2.1
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Freescale Semiconductor
EEPROM-1
EEDIVSECD — EEPROM-1 Divider Security Disable
This bit enables/disables the security feature of the EE1DIV registers.
When EE1DIV security feature is enabled, the state of the registers
EE1DIVH and EE1DIVL are locked (including EEDIVSECD bit). The
EE1DIVHNVR and EE1DIVLNVR non-volatile memory registers are
also protected from being erased/programmed.
1 = EE1DIV security feature disabled
0 = EE1DIV security feature enabled
EEDIV[10:0] — EEPROM-1 Timebase Prescaler
These prescaler bits store the value of EE1DIV which is used as the
divisor to derive a timebase of 35µs from the selected reference clock
source (CGMXCLK or bus clock in the MORB register) for the
EEPROM-1 related internal timer and circuits. EE1DIV[10:0] bits are
readable at any time. They are writable when EELAT = 0 and
EEDIVSECD = 1.
The EE1DIV value is calculated by the following formula:
EE1DIV= INT[Reference Frequency(Hz) x 35 x10-6 +0.5]
Where the result inside the bracket is rounded down to the nearest
integer value
For example, if the reference frequency is 4.9152MHz, the EE1DIV
value is 172
NOTE:
Programming/erasing the EEPROM-1 with an improper EE1DIV value
may result in data lost and reduce endurance of the EEPROM-1 device.
MC68HC08AZ60A — Rev 2.1
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Technical Data
EEPROM-1
75
EEPROM-1
5.6.5 EEPROM-1 Timebase Divider Non-Volatile Register
The 16-bit EEPROM-1 timebase divider non-volatile register consists of
two 8-bit registers: EE1DIVHNVR and EE1DIVLNVR. The contents of
these two registers are respectively loaded into the EEPROM-1
timebase divider registers, EE1DIVH and EE1DIVL, after a reset.
These two registers are erased and programmed in the same way as an
EEPROM-1 byte.
Address:
Read:
Write:
$FE10
Bit 7
6
5
4
3
2
1
Bit 0
EEDIVSECD
R
R
R
R
EEDIV10
EEDIV9
EEDIV8
Reset:
Unaffected by reset; $FF when blank
R
= Reserved
Figure 5-7. EEPROM-1 Divider Non-Volatile Register High
(EE1DIVHNVR))
Address:
Read:
Write:
Reset:
$FE11
Bit 7
6
5
4
3
2
1
Bit 0
EEDIV7
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
EEDIV1
EEDIV0
Unaffected by reset; $FF when blank
Figure 5-8. EEPROM-1 Divider Non-Volatile Register Low
(EE1DIVLNVR)
These two registers are protected from erase and program operations if
the EEDIVSECD is set to logic 1 in the EE1DIVH (see EEPROM-1
Timebase Divider Register) or programmed to a logic 1 in the
EE1DIVHNVR.
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EEPROM-1
NOTE:
Once EEDIVSECD in the EE1DIVHNVR is programmed to 0 and after a
system reset, the EE1DIV security feature is permanently enabled
because the EEDIVSECD bit in the EE1DIVH is always loaded with 0
thereafter. Once this security feature is armed, erase and program mode
are disabled for EE1DIVHNVR and EE1DIVLNVR. Modifications to the
EE1DIVH and EE1DIVL registers are also disabled. Therefore, care
should be taken before programming a value into the EE1DIVHNVR.
5.7 Low-Power Modes
The WAIT and STOP instructions can put the MCU in low powerconsumption standby modes.
5.7.1 Wait Mode
The WAIT instruction does not affect the EEPROM-1. It is possible to
start the program or erase sequence on the EEPROM-1 and put the
MCU in wait mode.
5.7.2 Stop Mode
The STOP instruction reduces the EEPROM-1 power consumption to a
minimum. The STOP instruction should not be executed while a
programming or erasing sequence is in progress.
If stop mode is entered while EELAT and EEPGM are set, the
programming sequence will be stopped and the programming voltage to
the EEPROM-1 array removed. The programming sequence will be
restarted after leaving stop mode; access to the EEPROM-1 is only
possible after the programming sequence has completed.
If stop mode is entered while EELAT and EEPGM is cleared, the
programming sequence will be terminated abruptly.
In either case, the data integrity of the EEPROM-1 is not guaranteed.
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Technical Data
EEPROM-1
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EEPROM-1
Technical Data
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MC68HC08AZ60A — Rev 2.1
EEPROM-1
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Technical Data — MC68HC08AZ60A
Section 6. EEPROM-2
6.1 Contents
6.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
6.4
EEPROM-2 Register Summary . . . . . . . . . . . . . . . . . . . . . . . 81
6.5
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.5.1
EEPROM-2 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.5.2
EEPROM-2 Timebase Requirements . . . . . . . . . . . . . . . . 82
6.5.3
EEPROM-2 Program/Erase Protection . . . . . . . . . . . . . . . 83
6.5.4
EEPROM-2 Block Protection . . . . . . . . . . . . . . . . . . . . . . . 84
6.5.5
EEPROM-2 Programming and Erasing. . . . . . . . . . . . . . . 84
6.6
EEPROM-2 Register Descriptions. . . . . . . . . . . . . . . . . . . . .89
6.6.1
EEPROM-2 Control Register . . . . . . . . . . . . . . . . . . . . . . . 89
6.6.2
EEPROM-2 Array Configuration Register . . . . . . . . . . . . 91
6.6.3
EEPROM-2 Nonvolatile Register. . . . . . . . . . . . . . . . . . . . 93
6.6.4
EEPROM-2 Timebase Divider Register . . . . . . . . . . . . . . 94
6.6.5
EEPROM-2 Timebase Divider Non-Volatile Register . . . 96
6.7
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.7.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.7.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.2 Introduction
This section describes the 512 bytes of electrically erasable
programmable read-only memory (EEPROM) residing at address range
$0600 to $07FF. There are 1024 bytes of EEPROM available on the
MC68HC08AZ60A which are physically located in two 512 byte arrays.
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Technical Data
EEPROM-2
79
EEPROM-2
For information relating to the array covering address range $0800 to
$09FF please see EEPROM-1 on page 59.
6.3 Features
Features of the EEPROM-2 include the following:
•
512 bytes Non-Volatile Memory
•
Byte, Block, or Bulk Erasable
•
Non-Volatile EEPROM-2 Configuration and Block Protection
Options
•
On-Chip Charge Pump for Programming/Erasing
•
Program/Erase Protection Option
•
Read Protection Option (in Monitor Mode)
•
AUTO Bit Driven Programming/Erasing Time Feature
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EEPROM-2
6.4 EEPROM-2 Register Summary
The EEPROM-2 Register Summary is shown in Figure 6-1.
Addr.
$FF70
$FF71
Register Name
Bit 7
Read:
EE2DIV Non-volatile
EEDIVSECD
Register High Write:
(EE2DIVHNVR)*
Reset:
Read:
EE2DIV Non-volatile
EEDIV7
Register Low Write:
(EE2DIVLNVR)*
Reset:
Read:
EEDIVSECD
EE2 Divider Register High
$FF7A
Write:
(EE2DIVH)
Reset:
Read:
EEDIV7
EE2 Divider Register Low
Write:
$FF7B
(EE2DIVL)
Reset:
$FF7C
$FF7D
$FF7F
6
5
4
3
2
1
Bit 0
R
R
R
R
EEDIV10
EEDIV9
EEDIV8
EEDIV1
EEDIV0
EEDIV9
EEDIV8
EEDIV1
EEDIV0
Unaffected by reset; $FF when blank
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
Unaffected by reset; $FF when blank
0
0
0
0
EEDIV10
Contents of EE2DIVHNVR ($FF70), Bits [6:3] = 0
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
Contents of EE2DIVLNVR ($FF71)
Read:
EEPROM-2 Non-volatile
UNUSED UNUSED UNUSED EEPRTCT EEBP3
EEBP2
EEBP1
Register Write:
(EE2NVR)*
Reset:
Unaffected by reset; $FF when blank; factory programmed $F0
Read:
EEPROM-2 Control
UNUSED
Register Write:
(EE2CR)
Reset:
0
0
0
EEBP0
EEOFF
EERAS1
EERAS0
EELAT
AUTO
EEPGM
0
0
0
0
0
0
EEBP1
EEBP0
Read: UNUSED UNUSED UNUSED EEPRTCT EEBP3
EEBP2
EEPROM-2 Array
Configuration Register Write:
(EE2ACR)
Reset:
Contents of EE2NVR ($FF7C)
* Non-volatile EEPROM register; write by programming.
= Unimplemented
R
= Reserved
UNUSED = Unused
Figure 6-1. EEPROM-2 Register Summary
MC68HC08AZ60A — Rev 2.1
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Technical Data
EEPROM-2
81
EEPROM-2
6.5 Functional Description
The 512 bytes of EEPROM-2 are located at $0600-$07FF and can be
programmed or erased without an additional external high voltage
supply. The program and erase operations are enabled through the use
of an internal charge pump. For each byte of EEPROM, the write/erase
endurance is 10,000 cycles.
6.5.1 EEPROM-2 Configuration
The 8-bit EEPROM-2 Non-Volatile Register (EE2NVR) and the 16-bit
EEPROM-2 Timebase Divider Non-Volatile Register (EE2DIVNVR)
contain the default settings for the following EEPROM-2 configurations:
•
EEPROM-2 Timebase Reference
•
EEPROM-2 Program/Erase Protection
•
EEPROM-2 Block Protection
EE2NVR and EE2DIVNVR are non-volatile EEPROM registers. They
are programmed and erased in the same way as EEPROM bytes. The
contents of these registers are loaded into their respective volatile
registers during a MCU reset. The values in these read/write volatile
registers define the EEPROM-2 configurations.
For EE2NVR, the corresponding volatile register is the EEPROM-2
Array Configuration Register (EEACR). For the EE2DIVNVR (two 8-bit
registers: EE2DIVHNVR and EE2DIVLNVR), the corresponding volatile
register is the EEPROM-2 Divider Register (EE2DIV: EE2DIVH and
EE2DIVL).
6.5.2 EEPROM-2 Timebase Requirements
A 35µs timebase is required by the EEPROM-2 control circuit for
program and erase of EEPROM-2 content. This timebase is derived
from dividing the CGMXCLK or bus clock (selected by EEDIVCLK bit in
Mask Option Register B) using a timebase divider circuit controlled by
the 16-bit EEPROM-2 Timebase Divider EE2DIV Register (EE2DIVH
and EE2DIVL).
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EEPROM-2
As the CGMXCLK or bus clock is user selected, the EEPROM-2
Timebase Divider Register must be configured with the appropriate
value to obtain the 35 µs. The timebase divider value is calculated by
using the following formula:
EE2DIV= INT[Reference Frequency(Hz) x 35 x10-6 +0.5]
This value is written to the EEPROM-2 Timebase Divider Register
(EE2DIVH and EE2DIVL) or programmed into the EEPROM-2
Timebase Divider Non-Volatile Register prior to any EEPROM-2
program or erase operations(see EEPROM-2 Configuration on page
82 and EEPROM-2 Timebase Requirements on page 82).
6.5.3 EEPROM-2 Program/Erase Protection
The EEPROM-2 has a special feature that designates the 16 bytes of
addresses from $06F0 to $06FF to be permanently secured. This
program/erase protect option is enabled by programming the EEPRTCT
bit in the EEPROM-2 Non-Volatile Register (EE2NVR) to a logic zero.
Once the EEPRTCT bit is programmed to 0 for the first time:
NOTE:
•
Programming and erasing of secured locations $06F0 to $06FF is
permanently disabled.
•
Secured locations $06F0 to $06FF can be read as normal.
•
Programming and erasing of EE2NVR is permanently disabled.
•
Bulk and Block Erase operations are disabled for the unprotected
locations $0600-$06EF, $0700-$07FF.
•
Single byte program and erase operations are still available for
locations $0600-$06EF and $0700-$07FF for all bytes that are not
protected by the EEPROM-2 Block Protect EEBPx bits (see
EEPROM-2 Block Protection on page 84 and EEPROM-2 Array
Configuration Register on page 91).
Once armed, the protect option is permanently enabled. As a
consequence, all functions in the EE2NVR will remain in the state they
were in immediately before the security was enabled.
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Technical Data
EEPROM-2
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EEPROM-2
6.5.4 EEPROM-2 Block Protection
The 512 bytes of EEPROM-2 are divided into four 128-byte blocks. Each
of these blocks can be protected from erase/program operations by
setting the EEBPx bit in the EE2NVR. Table 6-1 shows the address
ranges for the blocks.
Table 6-1. EEPROM-2 Array Address Blocks
Block Number (EEBPx)
Address Range
EEBP0
$0600–$067F
EEBP1
$0680–$06FF
EEBP2
$0700–$077F
EEBP3
$0780–$07FF
These bits are effective after a reset or a upon read of the EE2NVR
register. The block protect configuration can be modified by
erasing/programming the corresponding bits in the EE2NVR register
and then reading the EE2NVR register. Please see EEPROM-2 Array
Configuration Register on page 91 for more information.
NOTE:
Once EEDIVSECD in the EE2DIVHNVR is programmed to 0 and after a
system reset, the EE2DIV security feature is permanently enabled
because the EEDIVSECD bit in the EE2DIVH is always loaded with 0
thereafter. Once this security feature is armed, erase and program mode
are disabled for EE2DIVHNVR and EE2DIVLNVR. Modifications to the
EE2DIVH and EE2DIVL registers are also disabled. Therefore, be
cautious on programming a value into the EE2DIVHNVR.
6.5.5 EEPROM-2 Programming and Erasing
The unprogrammed or erase state of an EEPROM-2 bit is a logic 1. The
factory default for all bytes within the EEPROM-2 array is $FF.
The programming operation changes an EEPROM-2 bit from logic 1 to
logic 0 (programming cannot change a bit from logic 0 to a logic 1). In a
single programming operation, the minimum EEPROM-2 programming
size is one bit; the maximum is eight bits (one byte).
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EEPROM-2
The erase operation changes an EEPROM-2 bit from logic 0 to logic 1.
In a single erase operation, the minimum EEPROM-2 erase size is one
byte; the maximum is the entire EEPROM-2 array.
The EEPROM-2 can be programmed such that one or multiple bits are
programmed (written to a logic 0) at a time. However, the user may never
program the same bit location more than once before erasing the entire
byte. In other words, the user is not allowed to program a logic 0 to a bit
that is already programmed (bit state is already logic 0).
For some applications it might be advantageous to track more than 10K
events with a single byte of EEPROM-2 by programming one bit at a
time. For that purpose, a special selective bit programming technique is
available. An example of this technique is illustrated in Table 6-2.
Table 6-2. Example Selective Bit Programming Description
Program Data
in Binary
Result
in Binary
n/a
1111:1111
First event is recorded by programming bit position 0
1111:1110
1111:1110
Second event is recorded by programming bit position 1
1111:1101
1111:1100
Third event is recorded by programming bit position 2
1111:1011
1111:1000
Fourth event is recorded by programming bit position 3
1111:0111
1111:0000
Description
Original state of byte (erased)
Events five through eight are recorded in a similar fashion
Note that none of the bit locations are actually programmed more than
once although the byte was programmed eight times.
When this technique is utilized, a program/erase cycle is defined as
multiple program sequences (up to eight) to a unique location followed
by a single erase operation.
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Technical Data
EEPROM-2
85
EEPROM-2
6.5.5.1 Program/Erase Using AUTO Bit
An additional feature available for EEPROM-2 program and erase
operations is the AUTO mode. When enabled, AUTO mode will activate
an internal timer that will automatically terminate the program/erase
cycle and clear the EEPGM bit. Please see EEPROM-2 Programming
on page 86, EEPROM-2 Erasing on page 87 and EEPROM-2 Control
Register on page 89 for more information.
6.5.5.2 EEPROM-2 Programming
The unprogrammed or erase state of an EEPROM-2 bit is a logic 1.
Programming changes the state to a logic 0. Only EEPROM-2 bytes in
the non-protected blocks and the EE2NVR register can be programmed.
Use the following procedure to program a byte of EEPROM-2:
1. Clear EERAS1 and EERAS0 and set EELAT in the EE2CR.(A)
NOTE:
If using the AUTO mode, also set the AUTO bit during Step 1.
2. Write the desired data to the desired EEPROM-2 address.(B)
3. Set the EEPGM bit.(C) Go to Step 7 if AUTO is set.
4. Wait for time, tEEPGM, to program the byte.
5. Clear EEPGM bit.
6. Wait for time, tEEFPV, for the programming voltage to fall. Go to
Step 8.
7. Poll the EEPGM bit until it is cleared by the internal timer.(D)
8. Clear EELAT bits.(E)
NOTE:
A. EERAS1 and EERAS0 must be cleared for programming. Setting the
EELAT bit configures the address and data buses to latch data for
programming the array. Only data with a valid EEPROM-2 address will
be latched. If EELAT is set, other writes to the EE2CR will be allowed
after a valid EEPROM-2 write.
B. If more than one valid EEPROM-2 write occurs, the last address and
data will be latched overriding the previous address and data. Once data
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EEPROM-2
is written to the desired address, do not read EEPROM-2 locations other
than the written location. (Reading an EEPROM-2 location returns the
latched data and causes the read address to be latched).
C. The EEPGM bit cannot be set if the EELAT bit is cleared or a nonvalid EEPROM-2 address is latched. This is to ensure proper
programming sequence. Once EEPGM is set, do not read any
EEPROM-2 locations; otherwise, the current program cycle will be
unsuccessful. When EEPGM is set, the on-board programming
sequence will be activated.
D. The delay time for the EEPGM bit to be cleared in AUTO mode is less
than tEEPGM. However, on other MCUs, this delay time may be different.
For forward compatibility, software should not make any dependency on
this delay time.
E. Any attempt to clear both EEPGM and EELAT bits with a single
instruction will only clear EEPGM. This is to allow time for removal of
high voltage from the EEPROM-2 array.
6.5.5.3 EEPROM-2 Erasing
The programmed state of an EEPROM-2 bit is logic 0. Erasing changes
the state to a logic 1. Only EEPROM-2 bytes in the non-protected blocks
and the EE2NVR register can be erased.
Use the following procedure to erase a byte, block or the entire
EEPROM-2 array:
1. Configure EERAS1 and EERAS0 for byte, block or bulk erase; set
EELAT in EE2CR.(A)
NOTE:
If using the AUTO mode, also set the AUTO bit in Step 1.
2. Byte erase: write any data to the desired address.(B)
Block erase: write any data to an address within the desired
block.(B)
Bulk erase: write any data to an address within the array.(B)
3. Set the EEPGM bit.(C) Go to Step 7 if AUTO is set.
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Technical Data
EEPROM-2
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EEPROM-2
4. Wait for a time: tEEBYTE for byte erase; tEEBLOCK for block erase;
tEEBULK. for bulk erase.
5. Clear EEPGM bit.
6. Wait for a time, tEEFPV, for the erasing voltage to fall. Go to Step 8.
7. Poll the EEPGM bit until it is cleared by the internal timer.(D)
8. Clear EELAT bits.(E)
NOTE:
A. Setting the EELAT bit configures the address and data buses to latch
data for erasing the array. Only valid EEPROM-2 addresses will be
latched. If EELAT is set, other writes to the EE2CR will be allowed after
a valid EEPROM-2 write.
B. If more than one valid EEPROM-2 write occurs, the last address and
data will be latched overriding the previous address and data. Once data
is written to the desired address, do not read EEPROM-2 locations other
than the written location. (Reading an EEPROM-2 location returns the
latched data and causes the read address to be latched).
C. The EEPGM bit cannot be set if the EELAT bit is cleared or a nonvalid EEPROM-2 address is latched. This is to ensure proper
programming sequence. Once EEPGM is set, do not read any
EEPROM-2 locations; otherwise, the current program cycle will be
unsuccessful. When EEPGM is set, the on-board programming
sequence will be activated.
D. The delay time for the EEPGM bit to be cleared in AUTO mode is less
than tEEBYTE /tEEBLOCK/tEEBULK. However, on other MCUs, this delay
time may be different. For forward compatibility, software should not
make any dependency on this delay time.
E. Any attempt to clear both EEPGM and EELAT bits with a single
instruction will only clear EEPGM. This is to allow time for removal of
high voltage from the EEPROM-2 array.
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EEPROM-2
6.6 EEPROM-2 Register Descriptions
Four I/O registers and three non-volatile registers control program, erase
and options of the EEPROM-2 array.
6.6.1 EEPROM-2 Control Register
This read/write register controls programming/erasing of the array.
Address:
$FF7D
Bit 7
Read:
Write:
Reset:
UNUSED
0
6
0
0
5
4
3
2
1
Bit 0
EEOFF
EERAS1
EERAS0
EELAT
AUTO
EEPGM
0
0
0
0
0
0
= Unimplemented
Figure 6-2. EEPROM-2 Control Register (EE2CR)
Bit 7— Unused bit
This read/write bit is software programmable but has no functionality.
EEOFF — EEPROM-2 Power Down
This read/write bit disables the EEPROM-2 module for lower power
consumption. Any attempts to access the array will give unpredictable
results. Reset clears this bit.
1 = Disable EEPROM-2 array
0 = Enable EEPROM-2 array
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-2
89
EEPROM-2
EERAS1 and EERAS0 — Erase/Program Mode Select Bits
These read/write bits set the erase modes. Reset clears these bits.
Table 6-3. EEPROM-2 Program/Erase Mode Select
EEBPx
EERAS1
EERAS0
MODE
0
0
0
Byte Program
0
0
1
Byte Erase
0
1
0
Block Erase
0
1
1
Bulk Erase
1
X
X
No Erase/Program
X = don’t care
EELAT — EEPROM-2 Latch Control
This read/write bit latches the address and data buses for
programming the EEPROM-2 array. EELAT cannot be cleared if
EEPGM is still set. Reset clears this bit.
1 = Buses configured for EEPROM-2 programming or erase
operation
0 = Buses configured for normal operation
AUTO — Automatic Termination of Program/Erase Cycle
When AUTO is set, EEPGM is cleared automatically after the
program/erase cycle is terminated by the internal timer.
(See note D for EEPROM-2 Programming on page 86, EEPROM-2
Erasing on page 87 and EEPROM Memory Characteristics on
page 456)
1 = Automatic clear of EEPGM is enabled
0 = Automatic clear of EEPGM is disabled
EEPGM — EEPROM-2 Program/Erase Enable
This read/write bit enables the internal charge pump and applies the
programming/erasing voltage to the EEPROM-2 array if the EELAT
bit is set and a write to a valid EEPROM-2 location has occurred.
Reset clears the EEPGM bit.
1 = EEPROM-2 programming/erasing power switched on
0 = EEPROM-2 programming/erasing power switched off
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Freescale Semiconductor
EEPROM-2
NOTE:
Writing logic 0s to both the EELAT and EEPGM bits with a single
instruction will clear EEPGM only to allow time for the removal of high
voltage.
6.6.2 EEPROM-2 Array Configuration Register
The EEPROM-2 array configuration register configures EEPROM-2
security and EEPROM-2 block protection.
This read-only register is loaded with the contents of the EEPROM-2
non-volatile register (EE2NVR) after a reset.
Address:
$FF7F
Bit 7
6
5
4
Read: UNUSED UNUSED UNUSED EEPRTCT
3
2
1
Bit 0
EEBP3
EEBP2
EEBP1
EEBP0
Write:
Reset:
Contents of EE2NVR ($FF7C)
Figure 6-3. EEPROM-2 Array Configuration Register (EE2ACR)
Bit 7:5 — Unused Bits
These read/write bits are software programmable but have no
functionality.
EEPRTCT — EEPROM-2 Protection Bit
The EEPRTCT bit is used to enable the security feature in the
EEPROM-2 (see EEPROM-2 Program/Erase Protection on page
83).
1 = EEPROM-2 security disabled
0 = EEPROM-2 security enabled
This feature is a write-once feature. Once the protection is enabled it
may not be disabled.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
EEPROM-2
91
EEPROM-2
EEBP[3:0] — EEPROM-2 Block Protection Bits
These bits prevent blocks of EEPROM-2 array from being
programmed or erased.
1 = EEPROM-2 array block is protected
0 = EEPROM-2 array block is unprotected
Block Number (EEBPx)
Address Range
EEBP0
$0600–$067F
EEBP1
$0680–$06FF
EEBP2
$0700–$077F
EEBP3
$0780–$07FF
Table 6-4. EEPROM-2 Block Protect and Security Summary
Address Range
EEBPx
EEPRTCT = 1
EEPRTCT = 0
EEBP0 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP0 = 1
Protected
Protected
EEBP1 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP1 = 1
Protected
Protected
EEBP1 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Secured
(No Programming
or Erasing)
EEBP1 = 1
Protected
EEBP2 = 0
Byte Programming
Available
Bulk, Block and Byte
Erasing Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP2 = 1
Protected
Protected
$0600 - $067F
$0680 - $06EF
$06F0 - $06FF
$0700 - $077F
Technical Data
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EEPROM-2
Freescale Semiconductor
EEPROM-2
Table 6-4. EEPROM-2 Block Protect and Security Summary
Address Range
EEBPx
EEPRTCT = 1
EEPRTCT = 0
EEBP3 = 0
Byte Programming
Available
Bulk, Block and Byte
Available
Byte Programming
Available
Only Byte Erasing
Available
EEBP3 = 1
Protected
Protected
$0780 - $07FF
6.6.3 EEPROM-2 Nonvolatile Register
The contents of this register is loaded into the EEPROM-2 array
configuration register (EE2ACR) after a reset.
This register is erased and programmed in the same way as an
EEPROM-2 byte. (See EEPROM-2 Control Register on page 89 for
individual bit descriptions).
Address:
$FF7C
Bit 7
Read:
Write:
6
5
4
UNUSED UNUSED UNUSED EEPRTCT
Reset:
3
2
1
Bit 0
EEBP3
EEBP2
EEBP1
EEBP0
PV
= Unimplemented
PV = Programmed value or 1 in the erased state.
Figure 6-4. EEPROM-2 Nonvolatile Register (EE2NVR)
NOTE:
The EE2NVR will leave the factory programmed with $F0 such that the
full array is available and unprotected.
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EEPROM-2
6.6.4 EEPROM-2 Timebase Divider Register
The 16-bit EEPROM-2 timebase divider register consists of two 8-bit
registers: EE2DIVH and EE2DIVL. The 11-bit value in this register is
used to configure the timebase divider circuit to obtain the 35 µs
timebase for EEPROM-2 control.
These two read/write registers are respectively loaded with the contents
of the EEPROM-2 timebase divider non-volatile registers
(EE2DIVHNVR and EE2DIVLNVR) after a reset.
Address:
$FF7A
Bit 7
Read:
Write:
EEDIVSECD
6
5
4
3
0
0
0
0
Reset:
2
1
Bit 0
EEDIV10
EEDIV9
EEDIV8
Contents of EE2DIVHNVR ($FF70), Bits [6:3] = 0
= Unimplemented
Figure 6-5. EE2DIV Divider High Register (EE2DIVH)
Address:
Read:
Write:
Reset:
$FF7B
Bit 7
6
5
4
3
2
1
Bit 0
EEDIV7
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
EEDIV1
EEDIV0
Contents of EE2DIVLNVR ($FF71)
Figure 6-6. EE2DIV Divider Low Register (EE2DIVL)
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EEPROM-2
EEDIVSECD — EEPROM-2 Divider Security Disable
This bit enables/disables the security feature of the EE2DIV registers.
When EE2DIV security feature is enabled, the state of the registers
EE2DIVH and EE2DIVL are locked (including EEDIVSECD bit). The
EE2DIVHNVR and EE2DIVLNVR non-volatile memory registers are
also protected from being erased/programmed.
1 = EE2DIV security feature disabled
0 = EE2DIV security feature enabled
EEDIV[10:0] — EEPROM-2 Timebase Prescaler
These prescaler bits store the value of EE2DIV which is used as the
divisor to derive a timebase of 35µs from the selected reference clock
source (CGMXCLK or bus clock in the MORB register) for the
EEPROM-2 related internal timer and circuits. EE2DIV[10:0] bits are
readable at any time. They are writable when EELAT = 0 and
EEDIVSECD = 1.
The EE2DIV value is calculated by the following formula:
EE2DIV= INT[Reference Frequency(Hz) x 35 x10-6 +0.5]
Where the result inside the bracket is rounded down to the nearest
integer value
For example, if the reference frequency is 4.9152MHz, the EE2DIV
value is 172
NOTE:
Programming/erasing the EEPROM-2 with an improper EE2DIV value
may result in data lost and reduce endurance of the EEPROM-2 device.
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EEPROM-2
6.6.5 EEPROM-2 Timebase Divider Non-Volatile Register
The 16-bit EEPROM-2 timebase divider non-volatile register consists of
two 8-bit registers: EE2DIVHNVR and EE2DIVLNVR. The contents of
these two registers are respectively loaded into the EEPROM-2
timebase divider registers, EE2DIVH and EE2DIVL, after a reset.
These two registers are erased and programmed in the same way as an
EEPROM-2 byte.
Address:
Read:
Write:
$FF70
Bit 7
6
5
4
3
2
1
Bit 0
EEDIVSECD
R
R
R
R
EEDIV10
EEDIV9
EEDIV8
Reset:
Unaffected by reset; $FF when blank
R
= Reserved
Figure 6-7. EEPROM-2 Divider Non-Volatile Register High
(EE2DIVHNVR))
Address:
Read:
Write:
Reset:
$FF71
Bit 7
6
5
4
3
2
1
Bit 0
EEDIV7
EEDIV6
EEDIV5
EEDIV4
EEDIV3
EEDIV2
EEDIV1
EEDIV0
Unaffected by reset; $FF when blank
Figure 6-8. EEPROM-2 Divider Non-Volatile Register Low
(EE2DIVLNVR)
These two registers are protected from erase and program operations if
the EEDIVSECD is set to logic 1 in the EE2DIVH (see EEPROM-2
Timebase Divider Register) or programmed to a logic 1 in the
EE2DIVHNVR.
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Freescale Semiconductor
EEPROM-2
NOTE:
Once EEDIVSECD in the EE2DIVHNVR is programmed to 0 and after a
system reset, the EE2DIV security feature is permanently enabled
because the EEDIVSECD bit in the EE2DIVH is always loaded with 0
thereafter. Once this security feature is armed, erase and program mode
are disabled for EE2DIVHNVR and EE2DIVLNVR. Modifications to the
EE2DIVH and EE2DIVL registers are also disabled. Therefore, care
should be taken before programming a value into the EE2DIVHNVR.
6.7 Low-Power Modes
The WAIT and STOP instructions can put the MCU in low powerconsumption standby modes.
6.7.1 Wait Mode
The WAIT instruction does not affect the EEPROM-2. It is possible to
start the program or erase sequence on the EEPROM-2 and put the
MCU in wait mode.
6.7.2 Stop Mode
The STOP instruction reduces the EEPROM-2 power consumption to a
minimum. The STOP instruction should not be executed while a
programming or erasing sequence is in progress.
If stop mode is entered while EELAT and EEPGM are set, the
programming sequence will be stopped and the programming voltage to
the EEPROM-2 array removed. The programming sequence will be
restarted after leaving stop mode; access to the EEPROM-2 is only
possible after the programming sequence has completed.
If stop mode is entered while EELAT and EEPGM is cleared, the
programming sequence will be terminated abruptly.
In either case, the data integrity of the EEPROM-2 is not guaranteed.
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EEPROM-2
Technical Data
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Technical Data — MC68HC08AZ60A
Section 7. Central Processor Unit (CPU)
7.1 Contents
7.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
7.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
7.4
CPU registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
7.4.1
Accumulator (A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7.4.2
Index Register (H:X) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7.4.3
Stack Pointer (SP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102
7.4.4
Program Counter (PC) . . . . . . . . . . . . . . . . . . . . . . . . . . .102
7.4.5
Condition Code Register (CCR) . . . . . . . . . . . . . . . . . . . 103
7.5
Arithmetic/Logic Unit (ALU). . . . . . . . . . . . . . . . . . . . . . . . . 105
7.6
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
7.7
CPU During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . 106
7.8
Instruction Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . .107
7.9
Opcode Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115
7.2 Introduction
This section describes the central processor unit (CPU8). The M68HC08
CPU is an enhanced and fully object-code-compatible version of the
M68HC05 CPU. The CPU08 Reference Manual (Freescale document
number CPU08RM/AD) contains a description of the CPU instruction
set, addressing modes, and architecture.
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Central Processor Unit (CPU)
7.3 Features
Features of the CPU include the following:
•
Full upward, object-code compatibility with M68HC05 family
•
16-bit stack pointer with stack manipulation instructions
•
16-bit index register with X-register manipulation instructions
•
8.4MHz CPU internal bus frequency
•
64K byte program/data memory space
•
16 addressing modes
•
Memory-to-memory data moves without using accumulator
•
Fast 8-bit by 8-bit multiply and 16-bit by 8-bit divide instructions
•
Enhanced binary-coded decimal (BCD) data handling
•
Low-power STOP and WAIT Modes
7.4 CPU registers
Figure 7-1 shows the five CPU registers. CPU registers are not part of
the memory map.
0
7
ACCUMULATOR (A)
0
15
H
X
15
INDEX REGISTER (H:X)
0
STACK POINTER (SP)
15
0
PROGRAM COUNTER (PC)
7
0
V 1 1 H I N Z C CONDITION CODE REGISTER (CCR)
CARRY/BORROW FLAG
ZERO FLAG
NEGATIVE FLAG
INTERRUPT MASK
HALF-CARRY FLAG
TWO’S COMPLEMENT OVERFLOW FLAG
Figure 7-1. CPU Registers
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Central Processor Unit (CPU)
7.4.1 Accumulator (A)
The accumulator is a general-purpose 8-bit register. The CPU uses the
accumulator to hold operands and the results of arithmetic/logic
operations.
Bit 7
6
5
4
3
2
1
Bit 0
Read:
A
Write:
Reset:
Unaffected by reset
Figure 7-2. Accumulator (A)
7.4.2 Index Register (H:X)
The 16-bit index register allows indexed addressing of a 64K byte
memory space. H is the upper byte of the index register and X is the
lower byte. H:X is the concatenated 16-bit index register.
In the indexed addressing modes, the CPU uses the contents of the
index register to determine the conditional address of the operand.
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Bit
0
0
0
0
0
0
0
0
0
X
X
X
X
X
X
X
X
Read:
H:X
Write:
Reset:
X = Indeterminate
Figure 7-3. Index Register (H:X)
The index register can also be used as a temporary data storage
location.
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Central Processor Unit (CPU)
7.4.3 Stack Pointer (SP)
The stack pointer is a 16-bit register that contains the address of the next
location on the stack. During a reset, the stack pointer is preset to
$00FF. The reset stack pointer (RSP) instruction sets the least
significant byte to $FF and does not affect the most significant byte. The
stack pointer decrements as data is pushed onto the stack and
increments as data is pulled from the stack.
In the stack pointer 8-bit offset and 16-bit offset addressing modes, the
stack pointer can function as an index register to access data on the
stack. The CPU uses the contents of the stack pointer to determine the
conditional address of the operand.
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Bit
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Read:
SP
Write:
Reset:
Figure 7-4. Stack Pointer (SP)
NOTE:
The location of the stack is arbitrary and may be relocated anywhere in
RAM. Moving the SP out of page zero ($0000 to $00FF) frees direct
address (page zero) space. For correct operation, the stack pointer must
point only to RAM locations.
7.4.4 Program Counter (PC)
The program counter is a 16-bit register that contains the address of the
next instruction or operand to be fetched.
Normally, the program counter automatically increments to the next
sequential memory location every time an instruction or operand is
fetched. Jump, branch, and interrupt operations load the program
counter with an address other than that of the next sequential location.
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Central Processor Unit (CPU)
During reset, the program counter is loaded with the reset vector
address located at $FFFE and $FFFF. The vector address is the
address of the first instruction to be executed after exiting the reset state.
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
Bit
0
1
Read:
PC
Write:
Reset:
Loaded with vector from $FFFE and $FFFF
Figure 7-5. Program Counter (PC)
7.4.5 Condition Code Register (CCR)
The 8-bit condition code register contains the interrupt mask and five
flags that indicate the results of the instruction just executed. Bits 6 and
5 are set permanently to ‘1’. The following paragraphs describe the
functions of the condition code register.
Bit 7
6
5
4
3
2
1
Bit 0
V
1
1
H
I
N
Z
C
X
1
1
X
1
X
X
X
Read:
CCR
Write:
Reset:
X = Indeterminate
Figure 7-6. Condition Code Register (CCR)
V — Overflow Flag
The CPU sets the overflow flag when a two's complement overflow
occurs. The signed branch instructions BGT, BGE, BLE, and BLT use
the overflow flag.
1 = Overflow
0 = No overflow
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Central Processor Unit (CPU)
H — Half-Carry Flag
The CPU sets the half-carry flag when a carry occurs between
accumulator bits 3 and 4 during an ADD or ADC operation. The halfcarry flag is required for binary-coded decimal (BCD) arithmetic
operations. The DAA instruction uses the states of the H and C flags
to determine the appropriate correction factor.
1 = Carry between bits 3 and 4
0 = No carry between bits 3 and 4
I — Interrupt Mask
When the interrupt mask is set, all maskable CPU interrupts are
disabled. CPU interrupts are enabled when the interrupt mask is
cleared. When a CPU interrupt occurs, the interrupt mask is set
automatically after the CPU registers are saved on the stack, but
before the interrupt vector is fetched.
1 = Interrupts disabled
0 = Interrupts enabled
NOTE:
To maintain M6805 compatibility, the upper byte of the index register (H)
is not stacked automatically. If the interrupt service routine modifies H,
then the user must stack and unstack H using the PSHH and PULH
instructions.
After the I bit is cleared, the highest-priority interrupt request is
serviced first.
A return from interrupt (RTI) instruction pulls the CPU registers from the
stack and restores the interrupt mask from the stack. After any reset, the
interrupt mask is set and can only be cleared by the clear interrupt mask
software instruction (CLI).
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Central Processor Unit (CPU)
N — Negative Flag
The CPU sets the negative flag when an arithmetic operation, logic
operation, or data manipulation produces a negative result, setting bit
7 of the result.
1 = Negative result
0 = Non-negative result
Z — Zero Flag
The CPU sets the zero flag when an arithmetic operation, logic
operation, or data manipulation produces a result of $00.
1 = Zero result
0 = Non-zero result
C — Carry/Borrow Flag
The CPU sets the carry/borrow flag when an addition operation
produces a carry out of bit 7 of the accumulator or when a subtraction
operation requires a borrow. Some instructions - such as bit test and
branch, shift, and rotate - also clear or set the carry/borrow flag.
1 = Carry out of bit 7
0 = No carry out of bit 7
7.5 Arithmetic/Logic Unit (ALU)
The ALU performs the arithmetic and logic operations defined by the
instruction set.
Refer to the CPU08 Reference Manual (Freescale document number
CPU08RM/AD) for a description of the instructions and addressing
modes and more detail about CPU architecture.
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Central Processor Unit (CPU)
7.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low--power
consumption standby modes.
7.6.1 WAIT Mode
The WAIT instruction:
•
clears the interrupt mask (I bit) in the condition code register,
enabling interrupts. After exit from WAIT mode by interrupt, the I
bit remains clear. After exit by reset, the I bit is set.
•
Disables the CPU clock
7.6.2 STOP Mode
The STOP instruction:
•
clears the interrupt mask (I bit) in the condition code register,
enabling external interrupts. After exit from STOP mode by
external interrupt, the I bit remains clear. After exit by reset, the I
bit is set.
•
Disables the CPU clock
After exiting STOP mode, the CPU clock begins running after the
oscillator stabilization delay.
7.7 CPU During Break Interrupts
If the break module is enabled, a break interrupt causes the CPU to
execute the software interrupt instruction (SWI) at the completion of the
current CPU instruction. See Break Module. The program counter
vectors to $FFFC–$FFFD ($FEFC–$FEFD in monitor mode).
A return from interrupt instruction (RTI) in the break routine ends the
break interrupt and returns the MCU to normal operation if the break
interrupt has been deasserted.
Technical Data
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7.8 Instruction Set Summary
Table 7-1 provides a summary of the M68HC08 instruction set.
Operand
Description
Opcode
ADC #opr
ADC opr
ADC opr
ADC opr,X
ADC opr,X
ADC ,X
ADC opr,SP
ADC opr,SP
Operation
Effect on
CCR
IMM
DIR
EXT
↕ ↕ – ↕ ↕ ↕ IX2
IX1
IX
SP1
SP2
A9
B9
C9
D9
E9
F9
9E
E9
9E
D9
ii
dd
hh
ll
ee
ff
ff
IMM
DIR
EXT
IX2
↕ ↕ – ↕ ↕ ↕ IX1
IX
SP1
SP2
AB
BB
CB
DB
EB
FB
9E
EB
9E
DB
V HI NZ C
A ← (A) + (M) + (C)
Add with Carry
Address
Mode
Source
Form
ff
ee
ff
ii
dd
hh
ll
ee
ff
ff
Cycles
Table 7-1. Instruction Set Summary
2
3
4
4
3
2
4
5
2
3
4
4
3
2
4
5
ADD #opr
ADD opr
ADD opr
ADD opr,X
ADD opr,X
ADD ,X
ADD opr,SP
ADD opr,SP
Add without Carry
AIS #opr
Add Immediate Value (Signed) to
SP
SP ← (SP) + (16 « M)
– – – – – – IMM
A7
ii
2
AIX #opr
Add Immediate Value (Signed) to
H:X
H:X ← (H:X) + (16 « M)
– – – – – – IMM
AF
ii
2
A ← (A) & (M)
IMM
DIR
EXT
IX2
0 – – ↕ ↕ – IX1
IX
SP1
SP2
A4
B4
C4
D4
E4
F4
9E
E4
9E
D4
DIR
INH
INH
↕ – – ↕ ↕ ↕
IX1
IX
SP1
38
48
58
68
78
9E
68
DIR
INH
INH
↕ – – ↕ ↕ ↕ IX1
IX
SP1
37
47
57
67
77
9E
67
AND #opr
AND opr
AND opr
AND opr,X
AND opr,X
AND ,X
AND opr,SP
AND opr,SP
ASL opr
ASLA
ASLX
ASL opr,X
ASL ,X
ASL opr,SP
ASR opr
ASRA
ASRX
ASR opr,X
ASR opr,X
ASR opr,SP
A ← (A) + (M)
Logical AND
Arithmetic Shift Left
(Same as LSL)
C
0
b7
b0
C
Arithmetic Shift Right
b7
b0
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ff
ee
ff
ii
dd
hh
ll
ee
ff
ff
ff
ee
ff
dd
ff
ff
dd
ff
ff
2
3
4
4
3
2
4
5
4
1
1
4
3
5
4
1
1
4
3
5
Technical Data
Central Processor Unit (CPU)
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Central Processor Unit (CPU)
Table 7-1. Instruction Set Summary (Continued)
Opcode
Operand
Cycles
BCC rel
Operation
Effect on
CCR
PC ← (PC) + 2 + rel ? (C) = 0
– – – – – – REL
24
rr
3
Mn ← 0
DIR
(b0)
DIR
(b1)
DIR
(b2)
DIR
(b3)
– – – – – – DIR
(b4)
DIR
(b5)
DIR
(b6)
DIR
(b7)
11
13
15
17
19
1B
1D
1F
dd
dd
dd
dd
dd
dd
dd
dd
4
4
4
4
4
4
4
4
Description
V HI NZ C
Branch if Carry Bit Clear
Address
Mode
Source
Form
BCLR n, opr
Clear Bit n in M
BCS rel
Branch if Carry Bit Set (Same as
BLO)
PC ← (PC) + 2 + rel ? (C) = 1
– – – – – – REL
25
rr
3
BEQ rel
Branch if Equal
PC ← (PC) + 2 + rel ? (Z) = 1
– – – – – – REL
27
rr
3
BGE opr
Branch if Greater Than or Equal
To (Signed Operands)
PC ← (PC) + 2 + rel ? (N ⊕ V) = 0
– – – – – – REL
90
rr
3
BGT opr
Branch if Greater Than (Signed
Operands)
PC ← (PC) + 2 + rel ? (Z) | (N ⊕ V) =
0
– – – – – – REL
92
rr
3
BHCC rel
Branch if Half Carry Bit Clear
PC ← (PC) + 2 + rel ? (H) = 0
– – – – – – REL
28
rr
3
BHCS rel
Branch if Half Carry Bit Set
PC ← (PC) + 2 + rel ? (H) = 1
– – – – – – REL
29
rr
3
BHI rel
Branch if Higher
PC ← (PC) + 2 + rel ? (C) | (Z) = 0
– – – – – – REL
22
rr
3
BHS rel
Branch if Higher or Same
(Same as BCC)
PC ← (PC) + 2 + rel ? (C) = 0
– – – – – – REL
24
rr
3
BIH rel
Branch if IRQ Pin High
PC ← (PC) + 2 + rel ? IRQ = 1
– – – – – – REL
2F
rr
3
BIL rel
Branch if IRQ Pin Low
PC ← (PC) + 2 + rel ? IRQ = 0
– – – – – – REL
2E
rr
3
(A) & (M)
IMM
DIR
EXT
IX2
0 – – ↕ ↕ – IX1
IX
SP1
SP2
A5
B5
C5
D5
E5
F5
9E
E5
9E
D5
ii
dd
hh
ll
ee
ff
ff
2
3
4
4
3
2
4
5
BIT #opr
BIT opr
BIT opr
BIT opr,X
BIT opr,X
BIT ,X
BIT opr,SP
BIT opr,SP
Bit Test
BLE opr
Branch if Less Than or Equal To
(Signed Operands)
PC ← (PC) + 2 + rel ? (Z) | (N ⊕ V) =
1
– – – – – – REL
93
rr
3
BLO rel
Branch if Lower (Same as BCS)
PC ← (PC) + 2 + rel ? (C) = 1
– – – – – – REL
25
rr
3
BLS rel
Branch if Lower or Same
PC ← (PC) + 2 + rel ? (C) | (Z) = 1
– – – – – – REL
23
rr
3
BLT opr
Branch if Less Than (Signed
Operands)
PC ← (PC) + 2 + rel ? (N ⊕ V) =1
– – – – – – REL
91
rr
3
Technical Data
108
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ee
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Central Processor Unit (CPU)
Table 7-1. Instruction Set Summary (Continued)
Operand
Cycles
Branch if Interrupt Mask Clear
PC ← (PC) + 2 + rel ? (I) = 0
– – – – – – REL
2C
rr
3
BMI rel
Branch if Minus
PC ← (PC) + 2 + rel ? (N) = 1
– – – – – – REL
2B
rr
3
BMS rel
Branch if Interrupt Mask Set
PC ← (PC) + 2 + rel ? (I) = 1
– – – – – – REL
2D
rr
3
BNE rel
Branch if Not Equal
PC ← (PC) + 2 + rel ? (Z) = 0
– – – – – – REL
26
rr
3
BPL rel
Branch if Plus
PC ← (PC) + 2 + rel ? (N) = 0
– – – – – – REL
2A
rr
3
BRA rel
Branch Always
PC ← (PC) + 2 + rel
– – – – – – REL
20
rr
3
PC ← (PC) + 3 + rel ? (Mn) = 0
DIR
(b0)
DIR
(b1)
DIR
(b2)
DIR
– – – – – ↕ (b3)
DIR
(b4)
DIR
(b5)
DIR
(b6)
DIR
(b7)
01
03
05
07
09
0B
0D
0F
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
5
5
5
5
5
5
5
5
PC ← (PC) + 2
– – – – – – REL
21
rr
3
PC ← (PC) + 3 + rel ? (Mn) = 1
DIR
(b0)
DIR
(b1)
DIR
(b2)
DIR
(b3)
– – – – – ↕ DIR
(b4)
DIR
(b5)
DIR
(b6)
DIR
(b7)
00
02
04
06
08
0A
0C
0E
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
dd
rr
5
5
5
5
5
5
5
5
Mn ← 1
DIR
(b0)
DIR
(b1)
DIR
(b2)
DIR
– – – – – – (b3)
DIR
(b4)
DIR
(b5)
DIR
(b6)
DIR
(b7)
10
12
14
16
18
1A
1C
1E
dd
dd
dd
dd
dd
dd
dd
dd
4
4
4
4
4
4
4
4
Operation
V HI NZ C
BRCLR
n,opr,rel
Branch if Bit n in M Clear
BRN rel
Branch Never
BRSET
n,opr,rel
BSET n,opr
Description
Branch if Bit n in M Set
Set Bit n in M
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Address
Mode
Opcode
Effect on
CCR
BMC rel
Source
Form
Technical Data
Central Processor Unit (CPU)
109
Central Processor Unit (CPU)
Table 7-1. Instruction Set Summary (Continued)
Opcode
Operand
Cycles
BSR rel
Operation
Effect on
CCR
PC ← (PC) + 2; push (PCL)
SP ← (SP) – 1; push (PCH)
SP ← (SP) – 1
PC ← (PC) + rel
– – – – – – REL
AD
rr
4
PC ← (PC) + 3 + rel ? (A) – (M) = $00
PC ← (PC) + 3 + rel ? (A) – (M) = $00
PC ← (PC) + 3 + rel ? (X) – (M) = $00
PC ← (PC) + 3 + rel ? (A) – (M) = $00
PC ← (PC) + 2 + rel ? (A) – (M) = $00
PC ← (PC) + 4 + rel ? (A) – (M) = $00
DIR
IMM
IMM
– – – – – – IX1+
IX+
SP1
31
41
51
61
71
9E
61
dd
rr
ii rr
ii rr
ff rr
rr
ff rr
5
4
4
5
4
6
Description
V HI NZ C
Branch to Subroutine
Address
Mode
Source
Form
CBEQ opr,rel
CBEQA
#opr,rel
CBEQX
#opr,rel
CBEQ
opr,X+,rel
CBEQ X+,rel
CBEQ
opr,SP,rel
Compare and Branch if Equal
CLC
Clear Carry Bit
C←0
– – – – – 0 INH
98
1
CLI
Clear Interrupt Mask
I←0
– – 0 – – – INH
9A
2
M ← $00
A ← $00
X ← $00
H ← $00
M ← $00
M ← $00
M ← $00
DIR
INH
INH
0 – – 0 1 – INH
IX1
IX
SP1
3F
4F
5F
8C
6F
7F
9E
6F
(A) – (M)
IMM
DIR
EXT
IX2
↕ – – ↕ ↕ ↕ IX1
IX
SP1
SP2
A1
B1
C1
D1
E1
F1
9E
E1
9E
D1
DIR
INH
INH
0 – – ↕ ↕ 1
IX1
IX
SP1
33
43
53
63
73
9E
63
IMM
DIR
65
75
IMM
DIR
EXT
IX2
↕ – – ↕ ↕ ↕ IX1
IX
SP1
SP2
A3
B3
C3
D3
E3
F3
9E
E3
9E
D3
CLR opr
CLRA
CLRX
CLRH
CLR opr,X
CLR ,X
CLR opr,SP
CMP #opr
CMP opr
CMP opr
CMP opr,X
CMP opr,X
CMP ,X
CMP opr,SP
CMP opr,SP
Clear
Compare A with M
COM opr
COMA
COMX
COM opr,X
COM ,X
COM opr,SP
Complement (One’s
Complement)
CPHX #opr
CPHX opr
Compare H:X with M
CPX #opr
CPX opr
CPX opr
CPX ,X
CPX opr,X
CPX opr,X
CPX opr,SP
CPX opr,SP
Compare X with M
M ← (M) = $FF – (M)
A ← (A) = $FF – (M)
X ← (X) = $FF – (M)
M ← (M) = $FF – (M)
M ← (M) = $FF – (M)
M ← (M) = $FF – (M)
(H:X) – (M:M + 1)
(X) – (M)
Technical Data
110
↕ – – ↕ ↕ ↕
dd
ff
ff
ii
dd
hh
ll
ee
ff
ff
ff
ee
ff
dd
3
1
1
1
3
2
4
2
3
4
4
3
2
4
5
ff
4
1
1
4
3
5
ii
ii+1
dd
3
4
ff
ii
dd
hh
ll
ee
ff
ff
ff
ee
ff
2
3
4
4
3
2
4
5
MC68HC08AZ60A — Rev 2.1
Central Processor Unit (CPU)
Freescale Semiconductor
Central Processor Unit (CPU)
DAA
DBNZ opr,rel
DBNZA rel
DBNZX rel
DBNZ
opr,X,rel
DBNZ X,rel
DBNZ
opr,SP,rel
Decimal Adjust A
Decrement and Branch if Not
Zero
Decrement
DIV
Divide
INC opr
INCA
INCX
INC opr,X
INC ,X
INC opr,SP
JMP opr
JMP opr
JMP opr,X
JMP opr,X
JMP ,X
JSR opr
JSR opr
JSR opr,X
JSR opr,X
JSR ,X
Exclusive OR M with A
Increment
Jump
Jump to Subroutine
U – – ↕ ↕ ↕ INH
72
DIR
INH
– – – – – – INH
IX1
IX
SP1
3B
4B
5B
6B
7B
9E
6B
dd
rr
rr
rr
ff rr
rr
ff rr
5
3
3
5
4
6
M ← (M) – 1
A ← (A) – 1
X ← (X) – 1
M ← (M) – 1
M ← (M) – 1
M ← (M) – 1
DIR
INH
INH
↕ – – ↕ ↕ – IX1
IX
SP1
3A
4A
5A
6A
7A
9E
6A
dd
4
1
1
4
3
5
A ← (H:A)/(X)
H ← Remainder
– – – – ↕ ↕ INH
52
A ← (A ⊕ M)
IMM
DIR
EXT
IX2
0 – – ↕ ↕ –
IX1
IX
SP1
SP2
A8
B8
C8
D8
E8
F8
9E
E8
9E
D8
M ← (M) + 1
A ← (A) + 1
X ← (X) + 1
M ← (M) + 1
M ← (M) + 1
M ← (M) + 1
DIR
INH
↕ – – ↕ ↕ – INH
IX1
IX
SP1
3C
4C
5C
6C
7C
9E
6C
PC ← Jump Address
DIR
EXT
– – – – – – IX2
IX1
IX
PC ← (PC) + n (n = 1, 2, or 3)
Push (PCL); SP ← (SP) – 1
Push (PCH); SP ← (SP) – 1
PC ← Unconditional Address
DIR
EXT
– – – – – – IX2
IX1
IX
(A)10
A ← (A) – 1 or M ← (M) – 1 or X ← (X) –
1
PC ← (PC) + 3 + rel ? (result) ≠ 0
PC ← (PC) + 2 + rel ? (result) ≠ 0
PC ← (PC) + 2 + rel ? (result) ≠ 0
PC ← (PC) + 3 + rel ? (result) ≠ 0
PC ← (PC) + 2 + rel ? (result) ≠ 0
PC ← (PC) + 4 + rel ? (result) ≠ 0
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Cycles
V HI NZ C
DEC opr
DECA
DECX
DEC opr,X
DEC ,X
DEC opr,SP
EOR #opr
EOR opr
EOR opr
EOR opr,X
EOR opr,X
EOR ,X
EOR opr,SP
EOR opr,SP
Description
Operand
Operation
Effect on
CCR
Opcode
Source
Form
Address
Mode
Table 7-1. Instruction Set Summary (Continued)
2
ff
ff
7
ii
dd
hh
ll
ee
ff
ff
ff
ee
ff
dd
2
3
4
4
3
2
4
5
ff
4
1
1
4
3
5
BC
CC
DC
EC
FC
dd
hh
ll
ee
ff
ff
2
3
4
3
2
BD
CD
DD
ED
FD
dd
hh
ll
ee
ff
ff
4
5
6
5
4
ff
Technical Data
Central Processor Unit (CPU)
111
Central Processor Unit (CPU)
Load A from M
LDHX #opr
LDHX opr
Load H:X from M
LSL opr
LSLA
LSLX
LSL opr,X
LSL ,X
LSL opr,SP
LSR opr
LSRA
LSRX
LSR opr,X
LSR ,X
LSR opr,SP
IMM
DIR
EXT
IX2
0 – – ↕ ↕ – IX1
IX
SP1
SP2
A6
B6
C6
D6
E6
F6
9E
E6
9E
D6
H:X ← (M:M + 1)
IMM
0 – – ↕ ↕ – DIR
45
55
X ← (M)
IMM
DIR
EXT
IX2
0 – – ↕ ↕ –
IX1
IX
SP1
SP2
AE
BE
CE
DE
EE
FE
9E
EE
9E
DE
DIR
INH
↕ – – ↕ ↕ ↕ INH
IX1
IX
SP1
38
48
58
68
78
9E
68
DIR
INH
INH
↕ – – 0 ↕ ↕
IX1
IX
SP1
34
44
54
64
74
9E
64
H:X ← (H:X) + 1 (IX+D, DIX+)
DD
DIX+
0 – – ↕ ↕ –
IMD
IX+D
4E
5E
6E
7E
X:A ← (X) × (A)
– 0 – – – 0 INH
42
M ← –(M) = $00 – (M)
A ← –(A) = $00 – (A)
X ← –(X) = $00 – (X)
M ← –(M) = $00 – (M)
M ← –(M) = $00 – (M)
DIR
INH
INH
↕ – – ↕ ↕ ↕ IX1
IX
SP1
30
40
50
60
70
9E
60
A ← (M)
Load X from M
Logical Shift Left
(Same as ASL)
Logical Shift Right
C
0
b7
b0
0
C
b7
MOV opr,opr
MOV opr,X+
MOV #opr,opr
MOV X+,opr
Move
MUL
Unsigned multiply
b0
(M)Destination ← (M)Source
ii
dd
hh
ll
ee
ff
ff
ff
ee
ff
ii jj
dd
ii
dd
hh
ll
ee
ff
ff
ff
ee
ff
dd
ff
ff
dd
ff
ff
dd
dd
dd
ii
dd
dd
Cycles
V HI NZ C
LDA #opr
LDA opr
LDA opr
LDA opr,X
LDA opr,X
LDA ,X
LDA opr,SP
LDA opr,SP
LDX #opr
LDX opr
LDX opr
LDX opr,X
LDX opr,X
LDX ,X
LDX opr,SP
LDX opr,SP
Description
Operand
Operation
Effect on
CCR
Opcode
Source
Form
Address
Mode
Table 7-1. Instruction Set Summary (Continued)
2
3
4
4
3
2
4
5
3
4
2
3
4
4
3
2
4
5
4
1
1
4
3
5
4
1
1
4
3
5
5
4
4
4
5
dd
4
1
1
4
3
5
NEG opr
NEGA
NEGX
NEG opr,X
NEG ,X
NEG opr,SP
Negate (Two’s Complement)
NOP
No Operation
None
– – – – – – INH
9D
1
NSA
Nibble Swap A
A ← (A[3:0]:A[7:4])
– – – – – – INH
62
3
Technical Data
112
ff
ff
MC68HC08AZ60A — Rev 2.1
Central Processor Unit (CPU)
Freescale Semiconductor
Central Processor Unit (CPU)
V HI NZ C
ii
dd
hh
ll
ee
ff
ff
Cycles
Description
Operand
Operation
Effect on
CCR
Opcode
Source
Form
Address
Mode
Table 7-1. Instruction Set Summary (Continued)
IMM
DIR
EXT
IX2
0 – – ↕ ↕ – IX1
IX
SP1
SP2
AA
BA
CA
DA
EA
FA
9E
EA
9E
DA
Push (A); SP ← (SP) – 1
– – – – – – INH
87
2
Push H onto Stack
Push (H); SP ← (SP) – 1
– – – – – – INH
8B
2
PSHX
Push X onto Stack
Push (X); SP ← (SP) – 1
– – – – – – INH
89
2
PULA
Pull A from Stack
SP ← (SP + 1); Pull (A)
– – – – – – INH
86
2
PULH
Pull H from Stack
SP ← (SP + 1); Pull (H)
– – – – – – INH
8A
2
PULX
Pull X from Stack
SP ← (SP + 1); Pull (X)
– – – – – – INH
88
2
C
DIR
INH
↕ – – ↕ ↕ ↕ INH
IX1
IX
SP1
39
49
59
69
79
9E
69
DIR
INH
INH
↕ – – ↕ ↕ ↕
IX1
IX
SP1
36
46
56
66
76
9E
66
ORA #opr
ORA opr
ORA opr
ORA opr,X
ORA opr,X
ORA ,X
ORA opr,SP
ORA opr,SP
Inclusive OR A and M
PSHA
Push A onto Stack
PSHH
ROL opr
ROLA
ROLX
ROL opr,X
ROL ,X
ROL opr,SP
Rotate Left through Carry
A ← (A) | (M)
b7
b0
ff
ee
ff
dd
ff
ff
dd
2
3
4
4
3
2
4
5
4
1
1
4
3
5
4
1
1
4
3
5
ROR opr
RORA
RORX
ROR opr,X
ROR ,X
ROR opr,SP
Rotate Right through Carry
RSP
Reset Stack Pointer
SP ← $FF
– – – – – – INH
9C
1
RTI
Return from Interrupt
SP ← (SP) + 1; Pull (CCR)
SP ← (SP) + 1; Pull (A)
SP ← (SP) + 1; Pull (X)
SP ← (SP) + 1; Pull (PCH)
SP ← (SP) + 1; Pull (PCL)
↕ ↕ ↕ ↕ ↕ ↕ INH
80
7
RTS
Return from Subroutine
SP ← SP + 1; Pull (PCH)
SP ← SP + 1; Pull (PCL)
– – – – – – INH
81
4
A ← (A) – (M) – (C)
IMM
DIR
EXT
IX2
↕ – – ↕ ↕ ↕
IX1
IX
SP1
SP2
A2
B2
C2
D2
E2
F2
9E
E2
9E
D2
– – – – – 1 INH
99
C
b7
SBC #opr
SBC opr
SBC opr
SBC opr,X
SBC opr,X
SBC ,X
SBC opr,SP
SBC opr,SP
Subtract with Carry
SEC
Set Carry Bit
b0
C←1
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
ff
ff
ii
dd
hh
ll
ee
ff
ff
ff
ee
ff
2
3
4
4
3
2
4
5
1
Technical Data
Central Processor Unit (CPU)
113
Central Processor Unit (CPU)
SEI
Set Interrupt Mask
Store A in M
STHX opr
Store H:X in M
STOP
Enable IRQ Pin; Stop Oscillator
SUB #opr
SUB opr
SUB opr
SUB opr,X
SUB opr,X
SUB ,X
SUB opr,SP
SUB opr,SP
Store X in M
Subtract
Cycles
V HI NZ C
STA opr
STA opr
STA opr,X
STA opr,X
STA ,X
STA opr,SP
STA opr,SP
STX opr
STX opr
STX opr,X
STX opr,X
STX ,X
STX opr,SP
STX opr,SP
Description
Operand
Operation
Effect on
CCR
Opcode
Source
Form
Address
Mode
Table 7-1. Instruction Set Summary (Continued)
I←1
– – 1 – – – INH
9B
M ← (A)
DIR
EXT
IX2
0 – – ↕ ↕ – IX1
IX
SP1
SP2
B7
C7
D7
E7
F7
9E
E7
9E
D7
dd
hh
ll
ee
ff
ff
(M:M + 1) ← (H:X)
0 – – ↕ ↕ – DIR
35
dd
I ← 0; Stop Oscillator
– – 0 – – – INH
8E
M ← (X)
DIR
EXT
IX2
0 – – ↕ ↕ – IX1
IX
SP1
SP2
BF
CF
DF
EF
FF
9E
EF
9E
DF
dd
hh
ll
ee
ff
ff
IMM
DIR
EXT
↕ – – ↕ ↕ ↕ IX2
IX1
IX
SP1
SP2
A0
B0
C0
D0
E0
F0
9E
E0
9E
D0
ii
dd
hh
ll
ee
ff
ff
– – 1 – – – INH
83
9
A ← (A) – (M)
2
ff
ee
ff
3
4
4
3
2
4
5
4
1
ff
ee
ff
ff
ee
ff
3
4
4
3
2
4
5
2
3
4
4
3
2
4
5
SWI
Software Interrupt
PC ← (PC) + 1; Push (PCL)
SP ← (SP) – 1; Push (PCH)
SP ← (SP) – 1; Push (X)
SP ← (SP) – 1; Push (A)
SP ← (SP) – 1; Push (CCR)
SP ← (SP) – 1; I ← 1
PCH ← Interrupt Vector High Byte
PCL ← Interrupt Vector Low Byte
TAP
Transfer A to CCR
CCR ← (A)
↕ ↕ ↕ ↕ ↕ ↕ INH
84
2
TAX
Transfer A to X
X ← (A)
– – – – – – INH
97
1
TPA
Transfer CCR to A
A ← (CCR)
– – – – – – INH
85
1
(A) – $00 or (X) – $00 or (M) – $00
DIR
INH
INH
0 – – ↕ ↕ – IX1
IX
SP1
3D
4D
5D
6D
7D
9E
6D
– – – – – – INH
95
TST opr
TSTA
TSTX
TST opr,X
TST ,X
TST opr,SP
Test for Negative or Zero
TSX
Transfer SP to H:X
H:X ← (SP) + 1
Technical Data
114
dd
ff
ff
3
1
1
3
2
4
2
MC68HC08AZ60A — Rev 2.1
Central Processor Unit (CPU)
Freescale Semiconductor
Central Processor Unit (CPU)
1
V HI NZ C
TXA
Transfer X to A
TXS
Transfer H:X to SP
Cycles
Description
Operand
Operation
Effect on
CCR
Opcode
Source
Form
Address
Mode
Table 7-1. Instruction Set Summary (Continued)
A ← (X)
– – – – – – INH
9F
1
(SP) ← (H:X) – 1
– – – – – – INH
94
2
A Accumulatorn
C Carry/borrow bitopr
CCRCondition code registerPC
ddDirect address of operandPCH
dd rrDirect address of operand and relative offset of branch instructionPCL
DDDirect to direct addressing modeREL
DIRDirect addressing moderel
DIX+Direct to indexed with post increment addressing moderr
ee ffHigh and low bytes of offset in indexed, 16-bit offset addressingSP1
EXTExtended addressing modeSP2
ff Offset byte in indexed, 8-bit offset addressingSP
H Half-carry bitU
H Index register high byteV
hh llHigh and low bytes of operand address in extended addressingX
I Interrupt maskZ
ii Immediate operand byte&
IMDImmediate source to direct destination addressing mode|
IMMImmediate addressing mode⊕
INHInherent addressing mode( )
IXIndexed, no offset addressing mode–( )
IX+Indexed, no offset, post increment addressing mode#
IX+DIndexed with post increment to direct addressing mode«
IX1Indexed, 8-bit offset addressing mode←
IX1+Indexed, 8-bit offset, post increment addressing mode?
IX2Indexed, 16-bit offset addressing mode:
MMemory location↕
N Negative bit—
Any bit
Operand (one or two bytes)
Program counter
Program counter high byte
Program counter low byte
Relative addressing mode
Relative program counter offset byte
Relative program counter offset byte
Stack pointer, 8-bit offset addressing mode
Stack pointer 16-bit offset addressing mode
Stack pointer
Undefined
Overflow bit
Index register low byte
Zero bit
Logical AND
Logical OR
Logical EXCLUSIVE OR
Contents of
Negation (two’s complement)
Immediate value
Sign extend
Loaded with
If
Concatenated with
Set or cleared
Not affected
7.9 Opcode Map
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Central Processor Unit (CPU)
115
MSB
Branch
REL
DIR
INH
3
4
1
2
3
4
5
6
7
8
9
A
B
C
D
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
1
2
5
BRSET0
3 DIR
5
BRCLR0
3 DIR
5
BRSET1
3 DIR
5
BRCLR1
3 DIR
5
BRSET2
3 DIR
5
BRCLR2
3 DIR
5
BRSET3
3 DIR
5
BRCLR3
3 DIR
5
BRSET4
3 DIR
5
BRCLR4
3 DIR
5
BRSET5
3 DIR
5
BRCLR5
3 DIR
5
BRSET6
3 DIR
5
BRCLR6
3 DIR
5
BRSET7
3 DIR
5
BRCLR7
3 DIR
4
BSET0
2 DIR
4
BCLR0
2 DIR
4
BSET1
2 DIR
4
BCLR1
2 DIR
4
BSET2
2 DIR
4
BCLR2
2 DIR
4
BSET3
2 DIR
4
BCLR3
2 DIR
4
BSET4
2 DIR
4
BCLR4
2 DIR
4
BSET5
2 DIR
4
BCLR5
2 DIR
4
BSET6
2 DIR
4
BCLR6
2 DIR
4
BSET7
2 DIR
4
BCLR7
2 DIR
3
BRA
2 REL
3
BRN
2 REL
3
BHI
2 REL
3
BLS
2 REL
3
BCC
2 REL
3
BCS
2 REL
3
BNE
2 REL
3
BEQ
2 REL
3
BHCC
2 REL
3
BHCS
2 REL
3
BPL
2 REL
3
BMI
2 REL
3
BMC
2 REL
3
BMS
2 REL
3
BIL
2 REL
3
BIH
2 REL
5
6
1
NEGX
1 INH
4
CBEQX
3 IMM
7
DIV
1 INH
1
COMX
1 INH
1
LSRX
1 INH
4
LDHX
2 DIR
1
RORX
1 INH
1
ASRX
1 INH
1
LSLX
1 INH
1
ROLX
1 INH
1
DECX
1 INH
3
DBNZX
2 INH
1
INCX
1 INH
1
TSTX
1 INH
4
MOV
2 DIX+
1
CLRX
1 INH
4
NEG
2
IX1
5
CBEQ
3 IX1+
3
NSA
1 INH
4
COM
2 IX1
4
LSR
2 IX1
3
CPHX
3 IMM
4
ROR
2 IX1
4
ASR
2 IX1
4
LSL
2 IX1
4
ROL
2 IX1
4
DEC
2 IX1
5
DBNZ
3 IX1
4
INC
2 IX1
3
TST
2 IX1
4
MOV
3 IMD
3
CLR
2 IX1
SP1
IX
9E6
7
Control
INH
INH
8
9
Register/Memory
IX2
SP2
IMM
DIR
EXT
A
B
C
D
9ED
4
SUB
3 EXT
4
CMP
3 EXT
4
SBC
3 EXT
4
CPX
3 EXT
4
AND
3 EXT
4
BIT
3 EXT
4
LDA
3 EXT
4
STA
3 EXT
4
EOR
3 EXT
4
ADC
3 EXT
4
ORA
3 EXT
4
ADD
3 EXT
3
JMP
3 EXT
5
JSR
3 EXT
4
LDX
3 EXT
4
STX
3 EXT
4
SUB
3 IX2
4
CMP
3 IX2
4
SBC
3 IX2
4
CPX
3 IX2
4
AND
3 IX2
4
BIT
3 IX2
4
LDA
3 IX2
4
STA
3 IX2
4
EOR
3 IX2
4
ADC
3 IX2
4
ORA
3 IX2
4
ADD
3 IX2
4
JMP
3 IX2
6
JSR
3 IX2
4
LDX
3 IX2
4
STX
3 IX2
5
SUB
4 SP2
5
CMP
4 SP2
5
SBC
4 SP2
5
CPX
4 SP2
5
AND
4 SP2
5
BIT
4 SP2
5
LDA
4 SP2
5
STA
4 SP2
5
EOR
4 SP2
5
ADC
4 SP2
5
ORA
4 SP2
5
ADD
4 SP2
IX1
SP1
IX
E
9EE
F
LSB
0
Central Processor Unit (CPU)
0
Read-Modify-Write
INH
IX1
E
F
4
1
NEG
NEGA
2 DIR 1 INH
5
4
CBEQ CBEQA
3 DIR 3 IMM
5
MUL
1 INH
4
1
COM
COMA
2 DIR 1 INH
4
1
LSR
LSRA
2 DIR 1 INH
4
3
STHX
LDHX
2 DIR 3 IMM
4
1
ROR
RORA
2 DIR 1 INH
4
1
ASR
ASRA
2 DIR 1 INH
4
1
LSL
LSLA
2 DIR 1 INH
4
1
ROL
ROLA
2 DIR 1 INH
4
1
DEC
DECA
2 DIR 1 INH
5
3
DBNZ DBNZA
3 DIR 2 INH
4
1
INC
INCA
2 DIR 1 INH
3
1
TST
TSTA
2 DIR 1 INH
5
MOV
3 DD
3
1
CLR
CLRA
2 DIR 1 INH
INH Inherent
REL Relative
IMM Immediate
IX
Indexed, No Offset
DIR Direct
IX1 Indexed, 8-Bit Offset
EXT Extended
IX2 Indexed, 16-Bit Offset
DD Direct-Direct
IMD Immediate-Direct
IX+D Indexed-Direct DIX+ Direct-Indexed
*Pre-byte for stack pointer indexed instructions
5
3
NEG
NEG
3 SP1 1 IX
6
4
CBEQ
CBEQ
4 SP1 2 IX+
2
DAA
1 INH
5
3
COM
COM
3 SP1 1 IX
5
3
LSR
LSR
3 SP1 1 IX
4
CPHX
2 DIR
5
3
ROR
ROR
3 SP1 1 IX
5
3
ASR
ASR
3 SP1 1 IX
5
3
LSL
LSL
3 SP1 1 IX
5
3
ROL
ROL
3 SP1 1 IX
5
3
DEC
DEC
3 SP1 1 IX
6
4
DBNZ
DBNZ
4 SP1 2 IX
5
3
INC
INC
3 SP1 1 IX
4
2
TST
TST
3 SP1 1 IX
4
MOV
2 IX+D
4
2
CLR
CLR
3 SP1 1 IX
SP1 Stack Pointer, 8-Bit Offset
SP2 Stack Pointer, 16-Bit Offset
IX+ Indexed, No Offset with
Post Increment
IX1+ Indexed, 1-Byte Offset with
Post Increment
7
3
RTI
BGE
1 INH 2 REL
4
3
RTS
BLT
1 INH 2 REL
3
BGT
2 REL
9
3
SWI
BLE
1 INH 2 REL
2
2
TAP
TXS
1 INH 1 INH
1
2
TPA
TSX
1 INH 1 INH
2
PULA
1 INH
2
1
PSHA
TAX
1 INH 1 INH
2
1
PULX
CLC
1 INH 1 INH
2
1
PSHX
SEC
1 INH 1 INH
2
2
PULH
CLI
1 INH 1 INH
2
2
PSHH
SEI
1 INH 1 INH
1
1
CLRH
RSP
1 INH 1 INH
1
NOP
1 INH
1
STOP
*
1 INH
1
1
WAIT
TXA
1 INH 1 INH
2
SUB
2 IMM
2
CMP
2 IMM
2
SBC
2 IMM
2
CPX
2 IMM
2
AND
2 IMM
2
BIT
2 IMM
2
LDA
2 IMM
2
AIS
2 IMM
2
EOR
2 IMM
2
ADC
2 IMM
2
ORA
2 IMM
2
ADD
2 IMM
3
SUB
2 DIR
3
CMP
2 DIR
3
SBC
2 DIR
3
CPX
2 DIR
3
AND
2 DIR
3
BIT
2 DIR
3
LDA
2 DIR
3
STA
2 DIR
3
EOR
2 DIR
3
ADC
2 DIR
3
ORA
2 DIR
3
ADD
2 DIR
2
JMP
2 DIR
4
4
BSR
JSR
2 REL 2 DIR
2
3
LDX
LDX
2 IMM 2 DIR
2
3
AIX
STX
2 IMM 2 DIR
MSB
0
3
SUB
2 IX1
3
CMP
2 IX1
3
SBC
2 IX1
3
CPX
2 IX1
3
AND
2 IX1
3
BIT
2 IX1
3
LDA
2 IX1
3
STA
2 IX1
3
EOR
2 IX1
3
ADC
2 IX1
3
ORA
2 IX1
3
ADD
2 IX1
3
JMP
2 IX1
5
JSR
2 IX1
5
3
LDX
LDX
4 SP2 2 IX1
5
3
STX
STX
4 SP2 2 IX1
4
SUB
3 SP1
4
CMP
3 SP1
4
SBC
3 SP1
4
CPX
3 SP1
4
AND
3 SP1
4
BIT
3 SP1
4
LDA
3 SP1
4
STA
3 SP1
4
EOR
3 SP1
4
ADC
3 SP1
4
ORA
3 SP1
4
ADD
3 SP1
2
SUB
1 IX
2
CMP
1 IX
2
SBC
1 IX
2
CPX
1 IX
2
AND
1 IX
2
BIT
1 IX
2
LDA
1 IX
2
STA
1 IX
2
EOR
1 IX
2
ADC
1 IX
2
ORA
1 IX
2
ADD
1 IX
2
JMP
1 IX
4
JSR
1 IX
4
2
LDX
LDX
3 SP1 1 IX
4
2
STX
STX
3 SP1 1 IX
High Byte of Opcode in Hexadecimal
LSB
Low Byte of Opcode in Hexadecimal
Table 7-2. Opcode Map
0
5
Cycles
BRSET0 Opcode Mnemonic
3 DIR Number of Bytes / Addressing Mode
Central Processor Unit (CPU)
Technical Data
116
Bit Manipulation
DIR
DIR
Technical Data — MC68HC08AZ60A
Section 8. System Integration Module (SIM)
8.1 Contents
8.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
8.3
SIM Bus Clock Control and Generation . . . . . . . . . . . . . . . 120
8.3.1
BusTiming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.3.2
Clock Start-Up From POR or LVI Reset . . . . . . . . . . . . . 121
8.3.3
Clocks in STOP and WAIT Mode. . . . . . . . . . . . . . . . . . . 121
8.4
Reset and System Initialization . . . . . . . . . . . . . . . . . . . . . . 121
8.4.1
External Pin Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
8.4.2
Active Resets From Internal Sources. . . . . . . . . . . . . . . 123
8.4.2.1
Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8.4.2.2
Computer Operating Properly (COP) Reset. . . . . . . . 125
8.4.2.3
Illegal Opcode Reset . . . . . . . . . . . . . . . . . . . . . . . . . . 125
8.4.2.4
Illegal Address Reset. . . . . . . . . . . . . . . . . . . . . . . . . . 125
8.4.2.5
Low-Voltage Inhibit (LVI) Reset . . . . . . . . . . . . . . . . . 126
8.5
SIM Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
8.5.1
SIM Counter During Power-On Reset. . . . . . . . . . . . . . . 126
8.5.2
SIM Counter During STOP Mode Recovery . . . . . . . . . . 127
8.5.3
SIM Counter and Reset States . . . . . . . . . . . . . . . . . . . . 127
8.6
Exception Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8.6.1
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8.6.1.1
Hardware Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . .129
8.6.1.2
SWI Instruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.6.2
Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.7
Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.7.1
Status Flag Protection in Break Mode . . . . . . . . . . . . . . 130
8.8
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
8.8.1
WAIT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
8.8.2
STOP mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
System Integration Module (SIM)
117
System Integration Module (SIM)
8.9
SIM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
8.9.1
SIM Break Status Register (SBSR) . . . . . . . . . . . . . . . . . 134
8.9.2
SIM Reset Status Register (SRSR) . . . . . . . . . . . . . . . . . 136
8.9.3
SIM Break Flag Control Register (SBFCR). . . . . . . . . . . 137
8.2 Introduction
This section describes the system integration module, which supports up
to 24 external and/or internal interrupts. Together with the CPU, the SIM
controls all MCU activities. A block diagram of the SIM is shown in
Figure 8-1. Table 8-1 is a summary of the SIM I/O registers. The SIM is
a system state controller that coordinates CPU and exception timing.
The SIM is responsible for:
•
Bus clock generation and control for CPU and peripherals
– STOP/WAIT/reset/break entry and recovery
– Internal clock control
•
Master reset control, including power-on reset (POR) and COP
timeout
•
Interrupt control:
– Acknowledge timing
– Arbitration control timing
– Vector address generation
•
CPU enable/disable timing
Technical Data
118
MC68HC08AZ60A — Rev 2.1
System Integration Module (SIM)
Freescale Semiconductor
System Integration Module (SIM)
MODULE STOP
MODULE WAIT
CPU STOP (FROM CPU)
CPU WAIT (FROM CPU)
STOP/WAIT
CONTROL
SIMOSCEN (TO CGM)
SIM
COUNTER
COP CLOCK
CGMXCLK (FROM CGM)
CGMOUT (FROM CGM)
÷2
CLOCK
CONTROL
RESET
PIN LOGIC
CLOCK GENERATORS
INTERNAL CLOCKS
LVI (FROM LVI MODULE)
POR CONTROL
MASTER
RESET
CONTROL
RESET PIN CONTROL
ILLEGAL OPCODE (FROM CPU)
ILLEGAL ADDRESS (FROM ADDRESS
MAP DECODERS)
COP (FROM COP MODULE)
SIM RESET STATUS REGISTER
RESET
INTERRUPT SOURCES
INTERRUPT CONTROL
AND PRIORITY DECODE
CPU INTERFACE
Figure 8-1. SIM Block Diagram
Table 8-1. SIM I/O Register Summary
Register Name
SIM Break Status Register (SBSR)
SIM Reset Status Register (SRSR)
SIM Break Flag Control Register
(SBFCR)
R:
W:
Bit 7
6
5
4
3
2
R
R
R
R
R
R
PIN
COP
ILOP
ILAD
0
LVI
0
R
R
R
R
R
R
R
R: POR
BW
0
Bit 0
Addr.
R
$FE00
W:
BCFE
R
= Reserved for factory test
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
1
$FE01
$FE03
= Unimplemented
Technical Data
System Integration Module (SIM)
119
System Integration Module (SIM)
Table 8-2 shows the internal signal names used in this section.
Table 8-2. Signal Naming Conventions
Signal Name
Description
CGMXCLK
Buffered Version of OSC1 from Clock Generator Module (CGM)
CGMVCLK
PLL Output
CGMOUT
PLL-based or OSC1-based clock output from CGM Module
(Bus Clock = CGMOUT divided by two)
IAB
Internal Address Bus
IDB
Internal Data Bus
PORRST
Signal from the Power-on Reset Module to the SIM
IRST
Internal Reset Signal
R/W
Read/WriteSignal
8.3 SIM Bus Clock Control and Generation
The bus clock generator provides system clock signals for the CPU and
peripherals on the MCU. The system clocks are generated from an
incoming clock, CGMOUT, as shown in Figure 8-2. This clock can come
from either an external oscillator or from the on-chip PLL. See Clock
Generator Module (CGM).
CGMXCLK
OSC1
CGMVCLK
CLOCK
SELECT
CIRCUIT
÷2
A
CGMOUT
B S*
SIM COUNTER
BUS CLOCK
GENERATORS
÷2
*When S = 1,
CGMOUT = B
PLL
SIM
BCS
PTC3
MONITOR MODE
USER MODE
CGM
Figure 8-2. CGM Clock Signals
Technical Data
120
MC68HC08AZ60A — Rev 2.1
System Integration Module (SIM)
Freescale Semiconductor
System Integration Module (SIM)
8.3.1 BusTiming
In user mode, the internal bus frequency is either the crystal oscillator
output (CGMXCLK) divided by four or the PLL output (CGMVCLK)
divided by four. See Clock Generator Module (CGM).
8.3.2 Clock Start-Up From POR or LVI Reset
When the power-on reset module or the low-voltage inhibit module
generates a reset, the clocks to the CPU and peripherals are inactive
and held in an inactive phase until after the 4096 CGMXCLK cycle POR
timeout has been completed. The RST pin is driven low by the SIM
during this entire period. The bus clocks start upon completion of the
timeout.
8.3.3 Clocks in STOP and WAIT Mode
Upon exit from STOP mode (by an interrupt, break, or reset), the SIM
allows CGMXCLK to clock the SIM counter. The CPU and peripheral
clocks do not become active until after the STOP delay timeout. This
timeout is selectable as 4096 or 32 CGMXCLK cycles. See STOP
mode.
In WAIT mode, the CPU clocks are inactive. The SIM also produces two
sets of clocks for other modules. Refer to the WAIT mode subsection of
each module to see if the module is active or inactive in WAIT mode.
Some modules can be programmed to be active in WAIT mode.
8.4 Reset and System Initialization
The MCU has the following reset sources:
•
Power-on reset module (POR)
•
External reset pin (RST)
•
Computer operating properly module (COP)
•
Low-voltage inhibit module (LVI)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
System Integration Module (SIM)
121
System Integration Module (SIM)
•
Illegal opcode
•
Illegal address
All of these resets produce the vector $FFFE–FFFF ($FEFE–FEFF in
monitor mode) and assert the internal reset signal (IRST). IRST causes
all registers to be returned to their default values and all modules to be
returned to their reset states.
An internal reset clears the SIM counter, see SIM Counter on page 126,
but an external reset does not. Each of the resets sets a corresponding
bit in the SIM reset status register (SRSR). See SIM Registers.
8.4.1 External Pin Reset
Pulling the asynchronous RST pin low halts all processing. The PIN bit
of the SIM reset status register (SRSR) is set as long as RST is held low
for a minimum of 67 CGMXCLK cycles, assuming that neither the POR
nor the LVI was the source of the reset. See Table 8-3 for details. Figure
8-3 shows the relative timing.
Table 8-3. PIN Bit Set Timing
Reset type
Number of cycles required to set PIN
POR/LVI
4163 (4096 + 64 + 3)
All others
67 (64 + 3)
CGMOUT
RST
IAB
VECT H
PC
VECT L
Figure 8-3. External Reset Timing
Technical Data
122
MC68HC08AZ60A — Rev 2.1
System Integration Module (SIM)
Freescale Semiconductor
System Integration Module (SIM)
8.4.2 Active Resets From Internal Sources
All internal reset sources actively pull the RST pin low for 32 CGMXCLK
cycles to allow for resetting of external peripherals. The internal reset
signal IRST continues to be asserted for an additional 32 cycles. See
Figure 8-4. An internal reset can be caused by an illegal address, illegal
opcode, COP timeout, LVI, or POR. See Figure 8-5. Note that for LVI or
POR resets, the SIM cycles through 4096 CGMXCLK cycles, during
which the SIM forces the RST pin low. The internal reset signal then
follows the sequence from the falling edge of RST as shown in Figure
8-4.
IRST
RST
RST PULLED LOW BY MCU
32 CYCLES
32 CYCLES
CGMXCLK
IAB
VECTOR HIGH
Figure 8-4. Internal Reset Timing
The COP reset is asynchronous to the bus clock.
ILLEGAL ADDRESS RST
ILLEGAL OPCODE RST
COPRST
LVI
POR
INTERNAL RESET
Figure 8-5. Sources of Internal Reset
The active reset feature allows the part to issue a reset to peripherals
and other chips within a system built around the MCU.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
System Integration Module (SIM)
123
System Integration Module (SIM)
8.4.2.1 Power-On Reset
When power is first applied to the MCU, the power-on reset module
(POR) generates a pulse to indicate that power-on has occurred. The
external reset pin (RST) is held low while the SIM counter counts out
4096 CGMXCLK cycles. 64 CGMXCLK cycles later, the CPU and
memories are released from reset to allow the reset vector sequence to
occur.
At power-on, the following events occur:
•
A POR pulse is generated
•
The internal reset signal is asserted
•
The SIM enables CGMOUT
•
Internal clocks to the CPU and modules are held inactive for 4096
CGMXCLK cycles to allow the oscillator to stabilize
•
The RST pin is driven low during the oscillator stabilization time
•
The POR bit of the SIM reset status register (SRSR) is set and all
other bits in the register are cleared
OSC1
PORRST
4096
CYCLES
32
CYCLES
32
CYCLES
CGMXCLK
CGMOUT
RST
$FFFE
IAB
$FFFF
Figure 8-6. POR Recovery
Technical Data
124
MC68HC08AZ60A — Rev 2.1
System Integration Module (SIM)
Freescale Semiconductor
System Integration Module (SIM)
8.4.2.2 Computer Operating Properly (COP) Reset
An input to the SIM is reserved for the COP reset signal. The overflow of
the COP counter causes an internal reset and sets the COP bit in the
SIM reset status register (SRSR). The SIM actively pulls down the RST
pin for all internal reset sources.
To prevent a COP module timeout, a value (any value) should be written
to location $FFFF. Writing to location $FFFF clears the COP counter and
bits 12 through 4 of the SIM counter. The SIM counter output, which
occurs at least every 213 – 24 CGMXCLK cycles, drives the COP
counter. The COP should be serviced as soon as possible out of reset
to guarantee the maximum amount of time before the first timeout.
The COP module is disabled if the RST pin or the IRQ pin is held at
VDD + VHI while the MCU is in monitor mode. The COP module can be
disabled only through combinational logic conditioned with the high
voltage signal on the RST or the IRQ pin. This prevents the COP from
becoming disabled as a result of external noise. During a break state,
VDD + VHI on the RST pin disables the COP module.
8.4.2.3 Illegal Opcode Reset
The SIM decodes signals from the CPU to detect illegal instructions. An
illegal instruction sets the ILOP bit in the SIM reset status register
(SRSR) and causes a reset.
If the STOP enable bit, STOP, in the mask option register is logic ‘0’, the
SIM treats the STOP instruction as an illegal opcode and causes an
illegal opcode reset. The SIM actively pulls down the RST pin for all
internal reset sources.
8.4.2.4 Illegal Address Reset
An opcode fetch from an unmapped address generates an illegal
address reset. The SIM verifies that the CPU is fetching an opcode prior
to asserting the ILAD bit in the SIM reset status register SRSR) and
resetting the MCU. A data fetch from an unmapped address does not
generate a reset. The SIM actively pulls down the RST pin for all internal
reset sources.
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System Integration Module (SIM)
NOTE:
Extra care should be exercised if code in this part has been taken
from another HC08 with a different memory map since some legal
addresses could become illegal addresses on a smaller ROM. It is
the user’s responsibility to check their code for illegal addresses.
Older HC08s may have a different illegal address reset
specification.
8.4.2.5 Low-Voltage Inhibit (LVI) Reset
The low-voltage inhibit module (LVI) asserts its output to the SIM when
the VDD voltage falls to the LVITRIPF voltage. The LVI bit in the SIM reset
status register (SRSR) is set, and the external reset pin (RST) is held low
while the SIM counter counts out 4096 CGMXCLK cycles. 64 CGMXCLK
cycles later, the CPU is released from reset to allow the reset vector
sequence to occur. The SIM actively pulls down the RST pin for all
internal reset sources.
8.5 SIM Counter
The SIM counter is used by the power-on reset module (POR) and in
STOP mode recovery to allow the oscillator time to stabilize before
enabling the internal bus (IBUS) clocks. The SIM counter also serves as
a prescaler for the computer operating properly (COP) module. The SIM
counter overflow supplies the clock for the COP module. The SIM
counter is 13 bits long and is clocked by the falling edge of CGMXCLK.
8.5.1 SIM Counter During Power-On Reset
The power-on reset (POR) module detects power applied to the MCU.
At power-on, the POR circuit asserts the signal PORRST. Once the SIM
is initialized, it enables the clock generation module (CGM) to drive the
bus clock state machine.
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System Integration Module (SIM)
8.5.2 SIM Counter During STOP Mode Recovery
The SIM counter is also used for STOP mode recovery. The STOP
instruction clears the SIM counter. After an interrupt or reset, the SIM
senses the state of the short STOP recovery bit, SSREC, in the mask
option register. If the SSREC bit is a logic ‘1’, then the STOP recovery is
reduced from the normal delay of 4096 CGMXCLK cycles down to 32
CGMXCLK cycles. This is ideal for applications using canned oscillators
that do not require long start-up times from STOP mode. External crystal
applications should use the full STOP recovery time, that is, with SSREC
cleared.
8.5.3 SIM Counter and Reset States
External reset has no effect on the SIM counter. (See STOP mode for
details). The SIM counter is free-running after all reset states, see
Active Resets From Internal Sources on page 123 for counter control
and internal reset recovery sequences.
8.6 Exception Control
Normal, sequential program execution can be changed in three different
ways:
•
Interrupts
– Maskable hardware CPU interrupts
– Non-maskable software interrupt instruction (SWI)
•
Reset
•
Break interrupts
8.6.1 Interrupts
At the beginning of an interrupt, the CPU saves the CPU register
contents onto the stack and sets the interrupt mask (I-bit) to prevent
additional interrupts. At the end of an interrupt, the RTI instruction
recovers the CPU register contents from the stack so that normal
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System Integration Module (SIM)
processing can resume. Figure 8-7 shows interrupt entry timing, and
Figure 8-8 shows interrupt recovery timing.
.
MODULE
INTERRUPT
I-bit
IAB
IDB
DUMMY
SP
DUMMY
SP – 1
PC – 1[7:0]
SP – 2
PC–1[15:8]
SP – 3
X
SP – 4
A
VECT H
CCR
VECT L
V DATA H
START ADDRESS
V DATA L
OPCODE
R/W
Figure 8-7. Interrupt Entry
Interrupts are latched, and arbitration is performed in the SIM at the start
of interrupt processing. The arbitration result is a constant that the CPU
uses to determine which vector to fetch. Once an interrupt is latched by
the SIM, no other interrupt may take precedence, regardless of priority,
until the latched interrupt is serviced (or the I-bit is cleared). See Figure
8-8.
MODULE
INTERRUPT
I-BIT
IAB
IDB
SP – 4
SP – 2
SP – 3
CCR
A
SP – 1
X
PC – 1[7:0]
SP
PC
PC–1[15:8]
PC + 1
OPCODE
OPERAND
R/W
Figure 8-8. Interrupt Recovery
Technical Data
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System Integration Module (SIM)
8.6.1.1 Hardware Interrupts
Processing of a hardware interrupt begins after completion of the current
instruction. When the instruction is complete, the SIM checks all pending
hardware interrupts. If interrupts are not masked (I-bit clear in the
condition code register), and if the corresponding interrupt enable bit is
set, the SIM proceeds with interrupt processing; otherwise, the next
instruction is fetched and executed.
If more than one interrupt is pending at the end of an instruction
execution, the highest priority interrupt is serviced first. Figure 8-8
demonstrates what happens when two interrupts are pending. If an
interrupt is pending upon exit from the original interrupt service routine,
the pending interrupt is serviced before the LDA instruction is executed.
CLI
LDA #$FF
INT1
BACKGROUND ROUTINE
PSHH
INT1 INTERRUPT SERVICE ROUTINE
PULH
RTI
INT2
PSHH
INT2 INTERRUPT SERVICE ROUTINE
PULH
RTI
Figure 8-9. Interrupt Recognition Example
The LDA opcode is prefetched by both the INT1 and INT2 RTI
instructions. However, in the case of the INT1 RTI prefetch, this is a
redundant operation.
NOTE:
To maintain compatibility with the M6805 Family, the H register is not
pushed on the stack during interrupt entry. If the interrupt service routine
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System Integration Module (SIM)
modifies the H register or uses the indexed addressing mode, software
should save the H register and then restore it prior to exiting the routine.
8.6.1.2 SWI Instruction
The SWI instruction is a non-maskable instruction that causes an
interrupt regardless of the state of the interrupt mask (I-bit) in the
condition code register.
NOTE:
A software interrupt pushes PC onto the stack. A software interrupt does
not push PC – 1, as a hardware interrupt does.
8.6.2 Reset
All reset sources always have equal and highest priority and cannot be
arbitrated.
8.7 Break Interrupts
The break module can stop normal program flow at a softwareprogrammable break point by asserting its break interrupt output. See
Break Module. The SIM puts the CPU into the break state by forcing it
to the SWI vector location. Refer to the break interrupt subsection of
each module to see how each module is affected by the break state.
8.7.1 Status Flag Protection in Break Mode
The SIM controls whether status flags contained in other modules can
be cleared during break mode. The user can select whether flags are
protected from being cleared by properly initializing the break clear flag
enable bit (BCFE) in the SIM break flag control register (SBFCR).
Protecting flags in break mode ensures that set flags will not be cleared
while in break mode. This protection allows registers to be freely read
and written during break mode without losing status flag information.
Setting the BCFE bit enables the clearing mechanisms. Once cleared in
break mode, a flag remains cleared even when break mode is exited.
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System Integration Module (SIM)
Status flags with a two-step clearing mechanism — for example, a read
of one register followed by the read or write of another — are protected,
even when the first step is accomplished prior to entering break mode.
Upon leaving break mode, execution of the second step will clear the flag
as normal.
8.8 Low-Power Modes
Executing the STOP/WAIT instruction puts the MCU in a low-powerconsumption mode for standby situations. The SIM holds the CPU in a
non-clocked state. The operation of each of these modes is described
below. Both STOP and WAIT clear the interrupt mask (I) in the condition
code register, allowing interrupts to occur.
8.8.1 WAIT Mode
In WAIT mode, the CPU clocks are inactive while the peripheral clocks
continue to run. Figure 8-10 shows the timing for WAIT mode entry.
A module that is active during WAIT mode can wake up the CPU with an
interrupt if the interrupt is enabled. Stacking for the interrupt begins one
cycle after the WAIT instruction during which the interrupt occurred. In
WAIT mode, the CPU clocks are inactive. Refer to the WAIT mode
subsection of each module to see if the module is active or inactive in
WAIT mode. Some modules can be programmed to be active in WAIT
mode.
WAIT mode can also be exited by a reset or break. A break interrupt
during WAIT mode sets the SIM break WAIT bit, BW, in the SIM break
status register (SBSR). If the COP disable bit, COPD, in the mask option
register is ‘0’, then the computer operating properly (COP) module is
enabled and remains active in WAIT mode.
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System Integration Module (SIM)
WAIT ADDR
IAB
IDB
WAIT ADDR + 1
PREVIOUS DATA
SAME
NEXT OPCODE
SAME
SAME
SAME
R/W
NOTE: Previous data can be operand data or the WAIT opcode, depending on the
last instruction.
Figure 8-10. WAIT Mode Entry Timing
Figure 8-10 and Figure 8-12 show the timing for WAIT recovery.
IAB
$6E0B
IDB
$A6
$A6
$6E0C
$A6
$01
$00FF
$0B
$00FE
$00FD
$00FC
$6E
EXITSTOPWAIT
NOTE: EXITSTOPWAIT = RST pin OR CPU interrupt OR break interrupt
Figure 8-11. WAIT Recovery From Interrupt or Break
32
Cycles
IAB
$6E0B
IDB
$A6
$A6
32
Cycles
RST VCT H RST VCT L
$A6
RST
CGMXCLK
Figure 8-12. WAIT Recovery From Internal Reset
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System Integration Module (SIM)
8.8.2 STOP mode
In STOP mode, the SIM counter is reset and the system clocks are
disabled. An interrupt request from a module can cause an exit from
STOP mode. Stacking for interrupts begins after the selected STOP
recovery time has elapsed. Reset also causes an exit from STOP mode.
The SIM disables the clock generator module outputs (CGMOUT and
CGMXCLK) in STOP mode, stopping the CPU and peripherals. STOP
recovery time is selectable using the SSREC bit in the mask option
register (MOR). If SSREC is set, STOP recovery is reduced from the
normal delay of 4096 CGMXCLK cycles down to 32. This is ideal for
applications using canned oscillators that do not require long start-up
times from STOP mode.
NOTE:
External crystal applications should use the full STOP recovery time by
clearing the SSREC bit.
The break module is inactive in STOP mode. The STOP instruction does
not affect break module register states.
The SIM counter is held in reset from the execution of the STOP
instruction until the beginning of STOP recovery. It is then used to time
the recovery period. Figure 8-13 shows STOP mode entry timing.
CPUSTOP
IAB
IDB
STOP ADDR
STOP ADDR + 1
PREVIOUS DATA
NEXT OPCODE
SAME
SAME
SAME
SAME
R/W
NOTE: Previous data can be operand data or the STOP opcode, depending on the last
instruction.
Figure 8-13. STOP Mode Entry Timing
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System Integration Module (SIM)
STOP RECOVERY PERIOD
CGMXCLK
INT/BREAK
IAB
STOP + 2
STOP +1
STOP + 2
SP
SP – 1
SP – 2
SP – 3
Figure 8-14. STOP Mode Recovery From Interrupt
8.9 SIM Registers
The SIM has three memory mapped registers. Table 8-4 shows the
mapping of these registers.
Table 8-4. SIM Registers
Address
Register
Access mode
$FE00
SBSR
User
$FE01
SRSR
User
$FE03
SBFCR
User
8.9.1 SIM Break Status Register (SBSR)
The SIM break status register contains a flag to indicate that a break
caused an exit from STOP or WAIT mode.
SBSR
$FE00
Bit 7
6
5
4
3
2
R
R
R
R
R
R
1
Bit 0
BW
Read:
Write:
Note(1)
Reset:
0
R
= Reserved for factory test
R
1. Writing a logic ‘0’ clears BW.
Figure 8-15. SIM Break Status Register (SBSR)
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System Integration Module (SIM)
BW — SIM Break WAIT
This status bit is useful in applications requiring a return to WAIT
mode after exiting from a break interrupt. BW can be cleared by
writing a logic ‘0’ to it. Reset clears BW.
1 = WAIT mode was exited by break interrupt
0 = WAIT mode was not exited by break interrupt
BW can be read within the break state SWI routine. The user can modify
the return address on the stack by subtracting one from it. The following
code is an example of this.
; This code works if the H register has been pushed onto the stack in the break
; service routine software. This code should be executed at the end of the
; break service routine software.
HIBYTE
EQU
5
LOBYTE
EQU
6
;
If not BW, do RTI
BRCLR
BW,SBSR, RETURN
; See if WAIT mode was exited by break.
;
TST
LOBYTE,SP
; If RETURNLO is not ‘0’,
BNE
DOLO
; then just decrement low byte.
DEC
HIBYTE,SP
; Else deal with high byte, too.
DOLO
DEC
LOBYTE,SP
; Point to WAIT opcode.
RETURN
PULH
RTI
; Restore H register.
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System Integration Module (SIM)
8.9.2 SIM Reset Status Register (SRSR)
This register contains six flags that show the source of the last reset. The
SIM reset status register can be cleared by reading it. A power-on reset
sets the POR bit and clears all other bits in the register.
SRSR
$FE01
Read:
Bit 7
6
5
4
3
2
1
Bit 0
POR
PIN
COP
ILOP
ILAD
0
LVI
0
1
0
0
0
0
0
0
0
Write:
POR:
= Unimplemented
Figure 8-16. SIM Reset Status Register (SRSR)
POR — Power-On Reset Bit
1 = Last reset caused by POR circuit
0 = Read of SRSR
PIN — External Reset Bit
1 = Last reset caused by external reset pin (RST)
0 = POR or read of SRSR
COP — Computer Operating Properly Reset Bit
1 = Last reset caused by COP counter
0 = POR or read of SRSR
ILOP — Illegal Opcode Reset Bit
1 = Last reset caused by an illegal opcode
0 = POR or read of SRSR
ILAD — Illegal Address Reset Bit (opcode fetches only)
1 = Last reset caused by an opcode fetch from an illegal address
0 = POR or read of SRSR
LVI — Low-Voltage Inhibit Reset Bit
1 = Last reset was caused by the LVI circuit
0 = POR or read of SRSR
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System Integration Module (SIM)
8.9.3 SIM Break Flag Control Register (SBFCR)
The SIM break control register contains a bit that enables software to
clear status bits while the MCU is in a break state.
SBFCR
$FE03
Bit 7
6
5
4
3
2
1
Bit 0
BCFE
R
R
R
R
R
R
R
Read:
Write:
Reset:
0
R
= Reserved for factory test
Figure 8-17. SIM Break Flag Control Register (SBFCR)
BCFE — Break Clear Flag Enable Bit
This read/write bit enables software to clear status bits by accessing
status registers while the MCU is in a break state. To clear status bits
during the break state, the BCFE bit must be set.
1 = Status bits clearable during break
0 = Status bits not clearable during break
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System Integration Module (SIM)
Technical Data
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Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 9. Clock Generator Module (CGM)
9.1 Contents
9.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
9.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
9.4
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
9.4.1
Crystal Oscillator Circuit . . . . . . . . . . . . . . . . . . . . . . . . . 141
9.4.2
Phase-Locked Loop Circuit (PLL). . . . . . . . . . . . . . . . . . 143
9.4.2.1
Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143
9.4.2.2
Acquisition and Tracking Modes . . . . . . . . . . . . . . . . 145
9.4.2.3
Manual and Automatic PLL Bandwidth Modes . . . . . 145
9.4.2.4
Programming the PLL . . . . . . . . . . . . . . . . . . . . . . . . . 147
9.4.2.5
Special Programming Exceptions . . . . . . . . . . . . . . . 149
9.4.3
Base Clock Selector Circuit . . . . . . . . . . . . . . . . . . . . . . 149
9.4.4
CGM External Connections . . . . . . . . . . . . . . . . . . . . . . . 150
9.5
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
9.5.1
Crystal Amplifier Input Pin (OSC1) . . . . . . . . . . . . . . . . . 151
9.5.2
Crystal Amplifier Output Pin (OSC2) . . . . . . . . . . . . . . . 151
9.5.3
External Filter Capacitor Pin (CGMXFC) . . . . . . . . . . . . 151
9.5.4
Analog Power Pin (VDDA). . . . . . . . . . . . . . . . . . . . . . . . . 152
9.5.5
Oscillator Enable Signal (SIMOSCEN) . . . . . . . . . . . . . . 152
9.5.6
Crystal Output Frequency Signal (CGMXCLK) . . . . . . . 152
9.5.7
CGM Base Clock Output (CGMOUT) . . . . . . . . . . . . . . . 152
9.5.8
CGM CPU Interrupt (CGMINT) . . . . . . . . . . . . . . . . . . . . . 152
9.6
CGM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
9.6.1
PLL Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
9.6.2
PLL Bandwidth Control Register . . . . . . . . . . . . . . . . . . 155
9.6.3
PLL Programming Register. . . . . . . . . . . . . . . . . . . . . . . 157
9.7
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
9.8
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
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Clock Generator Module (CGM)
9.8.1
9.8.2
9.9
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
CGM During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . .160
9.10 Acquisition/Lock Time Specifications . . . . . . . . . . . . . . . . 160
9.10.1 Acquisition/Lock Time Definitions . . . . . . . . . . . . . . . . . 160
9.10.2 Parametric Influences on Reaction Time . . . . . . . . . . . . 162
9.10.3 Choosing a Filter Capacitor . . . . . . . . . . . . . . . . . . . . . . 163
9.10.4 Reaction Time Calculation . . . . . . . . . . . . . . . . . . . . . . .163
9.2 Introduction
The CGM generates the crystal clock signal, CGMXCLK, which operates
at the frequency of the crystal. The CGM also generates the base clock
signal, CGMOUT, from which the system clocks are derived. CGMOUT
is based on either the crystal clock divided by two or the phase-locked
loop (PLL) clock, CGMVCLK, divided by two. The PLL is a frequency
generator designed for use with 1-MHz to 16-MHz crystals or ceramic
resonators. The PLL can generate an 8-MHz bus frequency without
using high frequency crystals.
9.3 Features
Features of the CGM include:
•
Phase-Locked Loop with Output Frequency in Integer Multiples of
the Crystal Reference
•
Programmable Hardware Voltage-Controlled Oscillator (VCO) for
Low-Jitter Operation
•
Automatic Bandwidth Control Mode for Low-Jitter Operation
•
Automatic Frequency Lock Detector
•
CPU Interrupt on Entry or Exit from Locked Condition
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Clock Generator Module (CGM)
9.4 Functional Description
The CGM consists of three major submodules:
•
Crystal oscillator circuit — The crystal oscillator circuit generates
the constant crystal frequency clock, CGMXCLK.
•
Phase-locked loop (PLL) — The PLL generates the
programmable VCO frequency clock CGMVCLK.
•
Base clock selector circuit — This software-controlled circuit
selects either CGMXCLK divided by two or the VCO clock,
CGMVCLK, divided by two as the base clock, CGMOUT. The
system clocks are derived from CGMOUT.
Figure 9-1 shows the structure of the CGM.
9.4.1 Crystal Oscillator Circuit
The crystal oscillator circuit consists of an inverting amplifier and an
external crystal. The OSC1 pin is the input to the amplifier and the OSC2
pin is the output. The SIMOSCEN signal enables the crystal oscillator
circuit.
The CGMXCLK signal is the output of the crystal oscillator circuit and
runs at a rate equal to the crystal frequency. CGMXCLK is then buffered
to produce CGMRCLK, the PLL reference clock.
CGMXCLK can be used by other modules which require precise timing
for operation. The duty cycle of CGMXCLK is not guaranteed to be 50%
and depends on external factors, including the crystal and related
external components.
An externally generated clock also can feed the OSC1 pin of the crystal
oscillator circuit. Connect the external clock to the OSC1 pin and let the
OSC2 pin float.
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141
Clock Generator Module (CGM)
CGMXCLK
OSC1
CLOCK
SELECT
CIRCUIT
CGMRDV
÷2
CGMRCLK
A
CGMOUT
B S*
*When S = 1,
CGMOUT = B
BCS
VDDA
CGMXFC
PTC3
VSS
MONITOR MODE
VRS7–VRS4
USER MODE
PHASE
DETECTOR
VOLTAGE
CONTROLLED
OSCILLATOR
LOOP
FILTER
PLL ANALOG
LOCK
DETECTOR
LOCK
BANDWIDTH
CONTROL
AUTO
ACQ
INTERRUPT
CONTROL
PLLIE
CGMINT
PLLF
MUL7–MUL4
CGMVDV
FREQUENCY
DIVIDER
CGMVCLK
Figure 9-1. CGM Block Diagram
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Clock Generator Module (CGM)
Register Name
Bit 7
Read:
PLL Control Register (PCTL) Write:
Reset:
Read:
PLL Bandwidth Control Register
Write:
(PBWC)
Reset:
Read:
PLL Programming Register (PPG) Write:
Reset:
6
PLLF
PLLIE
0
0
LOCK
AUTO
5
4
PLLON
BCS
1
0
ACQ
XLD
3
2
1
Bit 0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
MUL7
MUL6
MUL5
MUL4
VRS7
VRS6
VRS5
VRS4
0
1
1
0
0
1
1
0
= Unimplemented
Figure 9-2. I/O Register Summary
Table 9-1. I/O Register Address Summary
Register
PCTL
PBWC
PPG
Address
$001C
$001D
$001E
9.4.2 Phase-Locked Loop Circuit (PLL)
The PLL is a frequency generator that can operate in either acquisition
mode or tracking mode, depending on the accuracy of the output
frequency. The PLL can change between acquisition and tracking
modes either automatically or manually.
9.4.2.1 Circuits
The PLL consists of these circuits:
•
Voltage-controlled oscillator (VCO)
•
Modulo VCO frequency divider
•
Phase detector
•
Loop filter
•
Lock detector
MC68HC08AZ60A — Rev 2.1
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Clock Generator Module (CGM)
The operating range of the VCO is programmable for a wide range of
frequencies and for maximum immunity to external noise, including
supply and CGMXFC noise. The VCO frequency is bound to a range
from roughly one-half to twice the center-of-range frequency, fCGMVRS.
Modulating the voltage on the CGMXFC pin changes the frequency
within this range. By design, fCGMVRS is equal to the nominal center-ofrange frequency, fNOM, (4.9152 MHz) times a linear factor L or (L)fNOM.
CGMRCLK is the PLL reference clock, a buffered version of CGMXCLK.
CGMRCLK runs at a frequency, fCGMRCLK, and is fed to the PLL through
a buffer. The buffer output is the final reference clock, CGMRDV,
running at a frequency fCGMRDV = fCGMRCLK.
The VCO’s output clock, CGMVCLK, running at a frequency fCGMVCLK,
is fed back through a programmable modulo divider. The modulo divider
reduces the VCO clock by a factor, N. The divider’s output is the VCO
feedback clock, CGMVDV, running at a frequency
fCGMVDV = fCGMVCLK/N. See Programming the PLL for more
information.
The phase detector then compares the VCO feedback clock, CGMVDV,
with the final reference clock, CGMRDV. A correction pulse is generated
based on the phase difference between the two signals. The loop filter
then slightly alters the dc voltage on the external capacitor connected to
CGMXFC based on the width and direction of the correction pulse. The
filter can make fast or slow corrections depending on its mode, as
described in Acquisition and Tracking Modes on page 145. The value
of the external capacitor and the reference frequency determines the
speed of the corrections and the stability of the PLL.
The lock detector compares the frequencies of the VCO feedback clock,
CGMVDV, and the final reference clock, CGMRDV. Therefore, the
speed of the lock detector is directly proportional to the final reference
frequency, fCGMRDV. The circuit determines the mode of the PLL and the
lock condition based on this comparison.
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9.4.2.2 Acquisition and Tracking Modes
The PLL filter is manually or automatically configurable into one of two
operating modes:
•
Acquisition mode — In acquisition mode, the filter can make large
frequency corrections to the VCO. This mode is used at PLL
startup or when the PLL has suffered a severe noise hit and the
VCO frequency is far off the desired frequency. When in
acquisition mode, the ACQ bit is clear in the PLL bandwidth control
register. See PLL Bandwidth Control Register on page 155.
•
Tracking mode — In tracking mode, the filter makes only small
corrections to the frequency of the VCO. PLL jitter is much lower
in tracking mode, but the response to noise is also slower. The
PLL enters tracking mode when the VCO frequency is nearly
correct, such as when the PLL is selected as the base clock
source. See Base Clock Selector Circuit on page 149. The PLL
is automatically in tracking mode when it’s not in acquisition mode
or when the ACQ bit is set.
9.4.2.3 Manual and Automatic PLL Bandwidth Modes
The PLL can change the bandwidth or operational mode of the loop filter
manually or automatically.
In automatic bandwidth control mode (AUTO = 1), the lock detector
automatically switches between acquisition and tracking modes.
Automatic bandwidth control mode also is used to determine when the
VCO clock, CGMVCLK, is safe to use as the source for the base clock,
CGMOUT. See PLL Bandwidth Control Register on page 155. If PLL
CPU interrupt requests are enabled, the software can wait for a PLL
CPU interrupt request and then check the LOCK bit. If CPU interrupts
are disabled, software can poll the LOCK bit continuously (during PLL
startup, usually) or at periodic intervals. In either case, when the LOCK
bit is set, the VCO clock is safe to use as the source for the base clock.
See Base Clock Selector Circuit on page 149. If the VCO is selected
as the source for the base clock and the LOCK bit is clear, the PLL has
suffered a severe noise hit and the software must take appropriate
action, depending on the application. See Interrupts on page 159.
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Clock Generator Module (CGM)
These conditions apply when the PLL is in automatic bandwidth control
mode:
•
The ACQ bit (See 9.6.2 PLL Bandwidth Control Register.) is a
read-only indicator of the mode of the filter. See Acquisition and
Tracking Modes on page 145.
•
The ACQ bit is set when the VCO frequency is within a certain
tolerance, ∆trk, and is cleared when the VCO frequency is out of a
certain tolerance, ∆unt. See Electrical Specifications on page 445.
•
The LOCK bit is a read-only indicator of the locked state of the
PLL.
•
The LOCK bit is set when the VCO frequency is within a certain
tolerance, ∆Lock, and is cleared when the VCO frequency is out of a
certain tolerance, ∆unl. See Electrical Specifications on page 445.
•
CPU interrupts can occur if enabled (PLLIE = 1) when the PLL’s
lock condition changes, toggling the LOCK bit. See PLL Control
Register on page 153.
The PLL also can operate in manual mode (AUTO = 0). Manual mode is
used by systems that do not require an indicator of the lock condition for
proper operation. Such systems typically operate well below fbusmax and
require fast startup. The following conditions apply when in manual
mode:
•
ACQ is a writable control bit that controls the mode of the filter.
Before turning on the PLL in manual mode, the ACQ bit must be
clear.
•
Before entering tracking mode (ACQ = 1), software must wait a
given time, tacq (see Electrical Specifications on page 445), after
turning on the PLL by setting PLLON in the PLL control register
(PCTL).
•
Software must wait a given time, tal, after entering tracking mode
before selecting the PLL as the clock source to CGMOUT
(BCS = 1).
•
The LOCK bit is disabled.
•
CPU interrupts from the CGM are disabled.
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9.4.2.4 Programming the PLL
Use this 9-step procedure to program the PLL. The table below lists the
variables used and their meaning (Please also reference Figure 9-1).
Table 9-2. Variable Definitions
Variable
Definition
fBUSDES
Desired Bus Clock Frequency
fVCLKDES
Desired VCO Clock Frequency
fCGMRCLK
Chosen Reference Crystal Frequency
fCGMVCLK
Calculated VCO Clock Frequency
fBUS
Calculated Bus Clock Frequency
fNOM
Nominal VCO Center Frequency
fCGMVRS
Shifted VCO Center Frequency
1. Choose the desired bus frequency, fBUSDES.
Example: fBUSDES = 8 MHz
2. Calculate the desired VCO frequency, fVCLKDES.
fVCLKDES = 4 × fBUSDES
Example: fVCLKDES = 4 × 8 MHz = 32 MHz
3. Using a reference frequency, fRCLK, equal to the crystal frequency,
calculate the VCO frequency multiplier, N. Round the result to the
nearest integer.
f VCLKDES
N = ------------------------fCGMRCLK
32 MHz
Example: N = -------------------- = 8
4 MHz
4. Calculate the VCO frequency, fCGMVCLK.
f CGMVCLK = N × f CGMRCLK
Example: fCGMVCLK = 8 × 4 MHz = 32 MHz
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5. Calculate the bus frequency, fBUS, and compare fBUS with
fBUSDES.
f CGMVCLK
f BUS = -----------------------4
32 MHz
Example: f BUS = -------------------- = 8 MHz
4
6. If the calculated fbus is not within the tolerance limits of your
application, select another fBUSDES or another fRCLK.
7. Using the value 4.9152 MHz for fNOM, calculate the VCO linear
range multiplier, L. The linear range multiplier controls the
frequency range of the PLL.
f CGMVCLK
L = round  ------------------------
 f NOM 
Example: L
=
32 MHz
-------------------------------- = 7
4.9152 MHz
8. Calculate the VCO center-of-range frequency, fCGMVRS. The
center-of-range frequency is the midpoint between the minimum
and maximum frequencies attainable by the PLL.
fCGMVRS = L × fNOM
Example: fCGMVRS = 7 × 4.9152 MHz = 34.4 MHz
NOTE:
f NOM
For proper operation, f CGMVRS – f CGMVCLK ≤ --------------.
2
Exceeding the recommended maximum bus frequency or VCO
frequency can crash the MCU.
9. Program the PLL registers accordingly:
a. In the upper four bits of the PLL programming register (PPG),
program the binary equivalent of N.
b. In the lower four bits of the PLL programming register (PPG),
program the binary equivalent of L.
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9.4.2.5 Special Programming Exceptions
The programming method described in Programming the PLL on page
147, does not account for two possible exceptions. A value of 0 for N or
L is meaningless when used in the equations given. To account for these
exceptions:
•
A 0 value for N is interpreted the same as a value of 1.
•
A 0 value for L disables the PLL and prevents its selection as the
source for the base clock. See Base Clock Selector Circuit on
page 149.
9.4.3 Base Clock Selector Circuit
This circuit is used to select either the crystal clock, CGMXCLK, or the
VCO clock, CGMVCLK, as the source of the base clock, CGMOUT. The
two input clocks go through a transition control circuit that waits up to
three CGMXCLK cycles and three CGMVCLK cycles to change from
one clock source to the other. During this time, CGMOUT is held in
stasis. The output of the transition control circuit is then divided by two
to correct the duty cycle. Therefore, the bus clock frequency, which is
one-half of the base clock frequency, is one-fourth the frequency of the
selected clock (CGMXCLK or CGMVCLK).
The BCS bit in the PLL control register (PCTL) selects which clock drives
CGMOUT. The VCO clock cannot be selected as the base clock source
if the PLL is not turned on. The PLL cannot be turned off if the VCO clock
is selected. The PLL cannot be turned on or off simultaneously with the
selection or deselection of the VCO clock. The VCO clock also cannot
be selected as the base clock source if the factor L is programmed to a
0. This value would set up a condition inconsistent with the operation of
the PLL, so that the PLL would be disabled and the crystal clock would
be forced as the source of the base clock.
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9.4.4 CGM External Connections
In its typical configuration, the CGM requires seven external
components. Five of these are for the crystal oscillator and two are for
the PLL.
The crystal oscillator is normally connected in a Pierce oscillator
configuration, as shown in Figure 9-3. Figure 9-3 shows only the logical
representation of the internal components and may not represent actual
circuitry. The oscillator configuration uses five components:
•
Crystal, X1
•
Fixed capacitor, C1
•
Tuning capacitor, C2 (can also be a fixed capacitor)
•
Feedback resistor, RB
•
Series resistor, RS (optional)
The series resistor (RS) may not be required for all ranges of operation,
especially with high-frequency crystals. Refer to the crystal
manufacturer’s data for more information.
Figure 9-3 also shows the external components for the PLL:
•
Bypass capacitor, CBYP
•
Filter capacitor, CF
Routing should be done with great care to minimize signal cross talk and
noise. (See Acquisition/Lock Time Specifications on page 160 for
routing information and more information on the filter capacitor’s value
and its effects on PLL performance).
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SIMOSCEN
RS*
VDDA
CGMXFC
VSS
OSC2
OSC1
CGMXCLK
VDD
CF
CBYP
RB
X1
C1
C2
*RS can be 0 (shorted) when used with higher-frequency crystals. Refer to manufacturer’s data.
Figure 9-3. CGM External Connections
9.5 I/O Signals
The following paragraphs describe the CGM input/output (I/O) signals.
9.5.1 Crystal Amplifier Input Pin (OSC1)
The OSC1 pin is an input to the crystal oscillator amplifier.
9.5.2 Crystal Amplifier Output Pin (OSC2)
The OSC2 pin is the output of the crystal oscillator inverting amplifier.
9.5.3 External Filter Capacitor Pin (CGMXFC)
The CGMXFC pin is required by the loop filter to filter out phase
corrections. A small external capacitor is connected to this pin.
NOTE:
To prevent noise problems, CF should be placed as close to the
CGMXFC pin as possible with minimum routing distances and no routing
of other signals across the CF connection.
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9.5.4 Analog Power Pin (VDDA)
VDDA is a power pin used by the analog portions of the PLL. Connect the
VDDA pin to the same voltage potential as the VDD pin.
NOTE:
Route VDDA carefully for maximum noise immunity and place bypass
capacitors as close as possible to the package.
9.5.5 Oscillator Enable Signal (SIMOSCEN)
The SIMOSCEN signal enables the oscillator and PLL.
9.5.6 Crystal Output Frequency Signal (CGMXCLK)
CGMXCLK is the crystal oscillator output signal. It runs at the full speed
of the crystal (fCGMXCLK) and comes directly from the crystal oscillator
circuit. Figure 9-3 shows only the logical relation of CGMXCLK to OSC1
and OSC2 and may not represent the actual circuitry. The duty cycle of
CGMXCLK is unknown and may depend on the crystal and other
external factors. Also, the frequency and amplitude of CGMXCLK can be
unstable at startup.
9.5.7 CGM Base Clock Output (CGMOUT)
CGMOUT is the clock output of the CGM. This signal is used to generate
the MCU clocks. CGMOUT is a 50% duty cycle clock running at twice the
bus frequency. CGMOUT is software programmable to be either the
oscillator output, CGMXCLK, divided by two or the VCO clock,
CGMVCLK, divided by two.
9.5.8 CGM CPU Interrupt (CGMINT)
CGMINT is the CPU interrupt signal generated by the PLL lock detector.
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9.6 CGM Registers
Three registers control and monitor operation of the CGM:
•
PLL control register (PCTL)
•
PLL bandwidth control register (PBWC)
•
PLL programming register (PPG)
9.6.1 PLL Control Register
The PLL control register contains the interrupt enable and flag bits, the
on/off switch, and the base clock selector bit.
Address:
$001C
Bit 7
Read:
Write:
Reset:
PLLIE
0
6
PLLF
0
5
4
PLLON
BCS
1
0
3
2
1
Bit 0
1
1
1
1
1
1
1
1
= Unimplemented
Figure 9-4. PLL Control Register (PCTL)
PLLIE — PLL Interrupt Enable Bit
This read/write bit enables the PLL to generate a CPU interrupt
request when the LOCK bit toggles, setting the PLL flag, PLLF. When
the AUTO bit in the PLL bandwidth control register (PBWC) is clear,
PLLIE cannot be written and reads as logic 0. Reset clears the PLLIE
bit.
1 = PLL CPU interrupt requests enabled
0 = PLL CPU interrupt requests disabled
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PLLF — PLL Flag Bit
This read-only bit is set whenever the LOCK bit toggles. PLLF
generates a CPU interrupt request if the PLLIE bit also is set. PLLF
always reads as logic 0 when the AUTO bit in the PLL bandwidth
control register (PBWC) is clear. Clear the PLLF bit by reading the
PLL control register. Reset clears the PLLF bit.
1 = Change in lock condition
0 = No change in lock condition
NOTE:
Do not inadvertently clear the PLLF bit. Be aware that any read or readmodify-write operation on the PLL control register clears the PLLF bit.
PLLON — PLL On Bit
This read/write bit activates the PLL and enables the VCO clock,
CGMVCLK. PLLON cannot be cleared if the VCO clock is driving the
base clock, CGMOUT (BCS = 1). See Base Clock Selector Circuit
on page 149. Reset sets this bit so that the loop can stabilize as the
MCU is powering up.
1 = PLL on
0 = PLL off
BCS — Base Clock Select Bit
This read/write bit selects either the crystal oscillator output,
CGMXCLK, or the VCO clock, CGMVCLK, as the source of the CGM
output, CGMOUT. CGMOUT frequency is one-half the frequency of
the selected clock. BCS cannot be set while the PLLON bit is clear.
After toggling BCS, it may take up to three CGMXCLK and three
CGMVCLK cycles to complete the transition from one source clock to
the other. During the transition, CGMOUT is held in stasis. See Base
Clock Selector Circuit on page 149. Reset and the STOP instruction
clear the BCS bit.
1 = CGMVCLK divided by two drives CGMOUT
0 = CGMXCLK divided by two drives CGMOUT
NOTE:
PLLON and BCS have built-in protection that prevents the base clock
selector circuit from selecting the VCO clock as the source of the base
clock if the PLL is off. Therefore, PLLON cannot be cleared when BCS
is set, and BCS cannot be set when PLLON is clear. If the PLL is off
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(PLLON = 0), selecting CGMVCLK requires two writes to the PLL control
register. See 9.4.3 on page 149.
PCTL3–PCTL0 — Unimplemented
These bits provide no function and always read as logic 1s.
9.6.2 PLL Bandwidth Control Register
The PLL bandwidth control register:
•
Selects automatic or manual (software-controlled) bandwidth
control mode
•
Indicates when the PLL is locked
•
In automatic bandwidth control mode, indicates when the PLL is in
acquisition or tracking mode
•
In manual operation, forces the PLL into acquisition or tracking
mode
Address:
$001D
Bit 7
Read:
Write:
Reset:
AUTO
0
6
LOCK
0
5
4
ACQ
XLD
0
0
3
2
1
Bit 0
0
0
0
0
0
0
0
0
= Unimplemented
Figure 9-5. PLL Bandwidth Control Register (PBWC)
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AUTO — Automatic Bandwidth Control Bit
This read/write bit selects automatic or manual bandwidth control.
When initializing the PLL for manual operation (AUTO = 0), clear the
ACQ bit before turning on the PLL. Reset clears the AUTO bit.
1 = Automatic bandwidth control
0 = Manual bandwidth control
LOCK — Lock Indicator Bit
When the AUTO bit is set, LOCK is a read-only bit that becomes set
when the VCO clock, CGMVCLK, is locked (running at the
programmed frequency). When the AUTO bit is clear, LOCK reads as
logic 0 and has no meaning. Reset clears the LOCK bit.
1 = VCO frequency correct or locked
0 = VCO frequency incorrect or unlocked
ACQ — Acquisition Mode Bit
When the AUTO bit is set, ACQ is a read-only bit that indicates
whether the PLL is in acquisition mode or tracking mode. When the
AUTO bit is clear, ACQ is a read/write bit that controls whether the
PLL is in acquisition or tracking mode.
In automatic bandwidth control mode (AUTO = 1), the last-written
value from manual operation is stored in a temporary location and is
recovered when manual operation resumes. Reset clears this bit,
enabling acquisition mode.
1 = Tracking mode
0 = Acquisition mode
XLD — Crystal Loss Detect Bit
When the VCO output, CGMVCLK, is driving CGMOUT, this
read/write bit can indicate whether the crystal reference frequency is
active or not.
1 = Crystal reference not active
0 = Crystal reference active
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To check the status of the crystal reference, do the following:
1. Write a logic 1 to XLD.
2. Wait N × 4 cycles. N is the VCO frequency multiplier.
3. Read XLD.
The crystal loss detect function works only when the BCS bit is set,
selecting CGMVCLK to drive CGMOUT. When BCS is clear, XLD
always reads as logic 0.
Bits 3–0 — Reserved for Test
These bits enable test functions not available in user mode. To ensure
software portability from development systems to user applications,
software should write 0s to bits 3–0 when writing to PBWC.
9.6.3 PLL Programming Register
The PLL programming register contains the programming information for
the modulo feedback divider and the programming information for the
hardware configuration of the VCO.
Address:
Read:
Write:
Reset:
$001E
Bit 7
6
5
4
3
2
1
Bit 0
MUL7
MUL6
MUL5
MUL4
VRS7
VRS6
VRS5
VRS4
0
1
1
0
0
1
1
0
Figure 9-6. PLL Programming Register (PPG)
MUL7–MUL4 — Multiplier Select Bits
These read/write bits control the modulo feedback divider that selects
the VCO frequency multiplier, N. (See Circuits on page 143 and
Programming the PLL on page 147). A value of $0 in the multiplier
select bits configures the modulo feedback divider the same as a
value of $1. Reset initializes these bits to $6 to give a default multiply
value of 6.
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Table 9-3. VCO Frequency Multiplier (N) Selection
NOTE:
MUL7:MUL6:MUL5:MUL4
VCO Frequency Multiplier (N)
0000
1
0001
1
0010
2
0011
3
1101
13
1110
14
1111
15
The multiplier select bits have built-in protection that prevents them from
being written when the PLL is on (PLLON = 1).
VRS7–VRS4 — VCO Range Select Bits
These read/write bits control the hardware center-of-range linear
multiplier L, which controls the hardware center-of-range frequency,
fVRS. (See Circuits on page 143, Programming the PLL on page
147, and PLL Control Register on page 153.) VRS7–VRS4 cannot
be written when the PLLON bit in the PLL control register (PCTL) is
set. See Special Programming Exceptions on page 149. A value of
$0 in the VCO range select bits disables the PLL and clears the BCS
bit in the PCTL. (See Base Clock Selector Circuit on page 149 and
Special Programming Exceptions on page 149 for more
information.) Reset initializes the bits to $6 to give a default range
multiply value of 6.
NOTE:
The VCO range select bits have built-in protection that prevents them
from being written when the PLL is on (PLLON = 1) and prevents
selection of the VCO clock as the source of the base clock (BCS = 1) if
the VCO range select bits are all clear.
The VCO range select bits must be programmed correctly. Incorrect
programming can result in failure of the PLL to achieve lock.
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9.7 Interrupts
When the AUTO bit is set in the PLL bandwidth control register (PBWC),
the PLL can generate a CPU interrupt request every time the LOCK bit
changes state. The PLLIE bit in the PLL control register (PCTL) enables
CPU interrupt requests from the PLL. PLLF, the interrupt flag in the
PCTL, becomes set whether CPU interrupt requests are enabled or not.
When the AUTO bit is clear, CPU interrupt requests from the PLL are
disabled and PLLF reads as logic 0.
Software should read the LOCK bit after a PLL CPU interrupt request to
see if the request was due to an entry into lock or an exit from lock. When
the PLL enters lock, the VCO clock, CGMVCLK, divided by two can be
selected as the CGMOUT source by setting BCS in the PCTL. When the
PLL exits lock, the VCO clock frequency is corrupt, and appropriate
precautions should be taken. If the application is not frequency sensitive,
CPU interrupt requests should be disabled to prevent PLL interrupt
service routines from impeding software performance or from exceeding
stack limitations.
NOTE:
Software can select the CGMVCLK divided by two as the CGMOUT
source even if the PLL is not locked (LOCK = 0). Therefore, software
should make sure the PLL is locked before setting the BCS bit.
9.8 Low-Power Modes
The WAIT and STOP instructions put the MCU in low powerconsumption standby modes.
9.8.1 Wait Mode
The CGM remains active in wait mode. Before entering wait mode,
software can disengage and turn off the PLL by clearing the BCS and
PLLON bits in the PLL control register (PCTL). Less power-sensitive
applications can disengage the PLL without turning it off. Applications
that require the PLL to wake the MCU from wait mode also can deselect
the PLL output without turning off the PLL.
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9.8.2 Stop Mode
The STOP instruction disables the CGM and holds low all CGM outputs
(CGMXCLK, CGMOUT, and CGMINT).
If CGMOUT is being driven by CGMVCLK and a STOP instruction is
executed; the PLL will clear the BCS bit in the PLL control register,
causing CGMOUT to be driven by CGMXCLK. When the MCU recovers
from STOP, the crystal clock divided by two drives CGMOUT and BCS
remains clear.
9.9 CGM During Break Interrupts
The BCFE bit in the break flag control register (BFCR) enables software
to clear status bits during the break state. See Break Module on page
171).
To allow software to clear status bits during a break interrupt, write a
logic 1 to the BCFE bit. If a status bit is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect the PLLF bit during the break state, write a logic 0 to the BCFE
bit. With BCFE at logic 0 (its default state), software can read and write
the PLL control register during the break state without affecting the PLLF
bit.
9.10 Acquisition/Lock Time Specifications
The acquisition and lock times of the PLL are, in many applications, the
most critical PLL design parameters. Proper design and use of the PLL
ensures the highest stability and lowest acquisition/lock times.
9.10.1 Acquisition/Lock Time Definitions
Typical control systems refer to the acquisition time or lock time as the
reaction time, within specified tolerances, of the system to a step input.
In a PLL, the step input occurs when the PLL is turned on or when it
suffers a noise hit. The tolerance is usually specified as a percent of the
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step input or when the output settles to the desired value plus or minus
a percent of the frequency change. Therefore, the reaction time is
constant in this definition, regardless of the size of the step input. For
example, consider a system with a 5% acquisition time tolerance. If a
command instructs the system to change from 0 Hz to 1 MHz, the
acquisition time is the time taken for the frequency to reach
1 MHz ±50 kHz. Fifty kHz = 5% of the 1-MHz step input. If the system is
operating at 1 MHz and suffers a –100 kHz noise hit, the acquisition time
is the time taken to return from 900 kHz to 1 MHz ±5 kHz. Five kHz = 5%
of the 100-kHz step input.
Other systems refer to acquisition and lock times as the time the system
takes to reduce the error between the actual output and the desired
output to within specified tolerances. Therefore, the acquisition or lock
time varies according to the original error in the output. Minor errors may
not even be registered. Typical PLL applications prefer to use this
definition because the system requires the output frequency to be within
a certain tolerance of the desired frequency regardless of the size of the
initial error.
The discrepancy in these definitions makes it difficult to specify an
acquisition or lock time for a typical PLL. Therefore, the definitions for
acquisition and lock times for this module are:
•
Acquisition time, tacq, is the time the PLL takes to reduce the error
between the actual output frequency and the desired output
frequency to less than the tracking mode entry tolerance, ∆trk.
Acquisition time is based on an initial frequency error,
(fdes – forig)/fdes, of not more than ±100%. In automatic bandwidth
control mode (see Manual and Automatic PLL Bandwidth
Modes on page 145), acquisition time expires when the ACQ bit
becomes set in the PLL bandwidth control register (PBWC).
•
Lock time, tLock, is the time the PLL takes to reduce the error
between the actual output frequency and the desired output
frequency to less than the lock mode entry tolerance, ∆Lock. Lock
time is based on an initial frequency error, (fdes – forig)/fdes, of not
more than ±100%. In automatic bandwidth control mode, lock time
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Technical Data
Clock Generator Module (CGM)
161
Clock Generator Module (CGM)
expires when the LOCK bit becomes set in the PLL bandwidth
control register (PBWC). (See Manual and Automatic PLL
Bandwidth Modes on page 145).
Obviously, the acquisition and lock times can vary according to how
large the frequency error is and may be shorter or longer in many cases.
9.10.2 Parametric Influences on Reaction Time
Acquisition and lock times are designed to be as short as possible while
still providing the highest possible stability. These reaction times are not
constant, however. Many factors directly and indirectly affect the
acquisition time.
The most critical parameter which affects the reaction times of the PLL
is the reference frequency, fCGMRDV (please reference Figure 9-1 on
page 142). This frequency is the input to the phase detector and controls
how often the PLL makes corrections. For stability, the corrections must
be small compared to the desired frequency, so several corrections are
required to reduce the frequency error. Therefore, the slower the
reference the longer it takes to make these corrections. This parameter
is also under user control via the choice of crystal frequency fCGMXCLK.
Another critical parameter is the external filter capacitor. The PLL
modifies the voltage on the VCO by adding or subtracting charge from
this capacitor. Therefore, the rate at which the voltage changes for a
given frequency error (thus a change in charge) is proportional to the
capacitor size. The size of the capacitor also is related to the stability of
the PLL. If the capacitor is too small, the PLL cannot make small enough
adjustments to the voltage and the system cannot lock. If the capacitor
is too large, the PLL may not be able to adjust the voltage in a
reasonable time. See Choosing a Filter Capacitor on page 163.
Also important is the operating voltage potential applied to VDDA. The
power supply potential alters the characteristics of the PLL. A fixed value
is best. Variable supplies, such as batteries, are acceptable if they vary
within a known range at very slow speeds. Noise on the power supply is
not acceptable, because it causes small frequency errors which
continually change the acquisition time of the PLL.
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Clock Generator Module (CGM)
Temperature and processing also can affect acquisition time because
the electrical characteristics of the PLL change. The part operates as
specified as long as these influences stay within the specified limits.
External factors, however, can cause drastic changes in the operation of
the PLL. These factors include noise injected into the PLL through the
filter capacitor, filter capacitor leakage, stray impedances on the circuit
board, and even humidity or circuit board contamination.
9.10.3 Choosing a Filter Capacitor
As described in Parametric Influences on Reaction Time on page
162, the external filter capacitor, CF, is critical to the stability and reaction
time of the PLL. The PLL is also dependent on reference frequency and
supply voltage. The value of the capacitor must, therefore, be chosen
with supply potential and reference frequency in mind. For proper
operation, the external filter capacitor must be chosen according to this
equation:
V DDA 
C F = C fact  ----------------- f C G M R D V
For acceptable values of Cfact, (see Electrical Specifications on page
445). For the value of VDDA, choose the voltage potential at which the
MCU is operating. If the power supply is variable, choose a value near
the middle of the range of possible supply values.
This equation does not always yield a commonly available capacitor
size, so round to the nearest available size. If the value is between two
different sizes, choose the higher value for better stability. Choosing the
lower size may seem attractive for acquisition time improvement, but the
PLL may become unstable. Also, always choose a capacitor with a tight
tolerance (±20% or better) and low dissipation.
9.10.4 Reaction Time Calculation
The actual acquisition and lock times can be calculated using the
equations below. These equations yield nominal values under the
following conditions:
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Technical Data
Clock Generator Module (CGM)
163
Clock Generator Module (CGM)
•
Correct selection of filter capacitor, CF (see Choosing a Filter
Capacitor on page 163).
•
Room temperature operation
•
Negligible external leakage on CGMXFC
•
Negligible noise
The K factor in the equations is derived from internal PLL parameters.
Kacq is the K factor when the PLL is configured in acquisition mode, and
Ktrk is the K factor when the PLL is configured in tracking mode. (See
Acquisition and Tracking Modes on page 145).
V DDA   8 
- ------------t acq =  ------------------ f CGMRDV  K ACQ
V DDA   4 
- -----------t al =  ------------------ f CGMRDV  K TRK
t Lock = t ACQ + t AL
Note the inverse proportionality between the lock time and the reference
frequency.
In automatic bandwidth control mode, the acquisition and lock times are
quantized into units based on the reference frequency. (See Manual
and Automatic PLL Bandwidth Modes on page 145). A certain
number of clock cycles, nACQ, is required to ascertain that the PLL is
within the tracking mode entry tolerance, ∆TRK, before exiting acquisition
mode. A certain number of clock cycles, nTRK, is required to ascertain
that the PLL is within the lock mode entry tolerance, ∆Lock. Therefore, the
acquisition time, tACQ, is an integer multiple of nACQ/fCGMRDV, and the
acquisition to lock time, tAL, is an integer multiple of nTRK/fCGMRDV. Also,
since the average frequency over the entire measurement period must
be within the specified tolerance, the total time usually is longer than
tLock as calculated above.
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Clock Generator Module (CGM)
Freescale Semiconductor
Clock Generator Module (CGM)
In manual mode, it is usually necessary to wait considerably longer than
tLock before selecting the PLL clock (see Base Clock Selector Circuit
on page 149), because the factors described in Parametric Influences
on Reaction Time on page 162, may slow the lock time considerably.
When defining a limit in software for the maximum lock time, the value
must allow for variation due to all of the factors mentioned in this section,
especially due to the CF capacitor and application specific influences.
The calculated lock time is only an indication and it is the customer’s
responsibility to allow enough of a guard band for their application. Prior
to finalizing any software and while determining the maximum lock time,
take into account all device to device differences. Typically, applications
set the maximum lock time as an order of magnitude higher than the
measured value. This is considered sufficient for all such device to
device variation.
Freescale recommends measuring the lock time of the application
system by utilizing dedicated software, running in FLASH, EEPROM or
RAM. This should toggle a port pin when the PLL is first configured and
switched on, then again when it goes from acquisition to lock mode and
finally again when the PLL lock bit is set. The resultant waveform can be
captured on an oscilloscope and used to determine the typical lock time
for the microcontroller and the associated external application circuit.
e.g.
tLOCK
tACQ
tAL
Init. low
Signal on port pin
tTRKComplete and Lock Set
tACQComplete
PLL Configured and switched on
NOTE:
The filter capacitor should be fully discharged prior to making any
measurements.
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Technical Data
Clock Generator Module (CGM)
165
Clock Generator Module (CGM)
Technical Data
166
MC68HC08AZ60A — Rev 2.1
Clock Generator Module (CGM)
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 10. Mask Options
10.1 Contents
10.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
10.3
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
10.2 Introduction
This section describes the mask options and the mask option registers.
The mask options are hardwired connections specified at the same time
as the ROM code, which allow the user to customize the MCU. The
options control the enable or disable of the following functions:
•
Resets caused by the LVI module
•
Power to the LVI module
•
Stop mode recovery time (32 CGMXCLK cycles or 4096
CGMXCLK cycles)
•
ROM security(1)
•
STOP instruction
•
Computer operating properly (COP) module enable
•
EEPROM read protection(1)
•
COP time-out period
•
EEPROM reference clock source
1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or
copying the ROM/EEPROM data difficult for unauthorized users
MC68HC08AZ60A — Rev 2.1
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Technical Data
Mask Options
167
Mask Options
10.3 Functional Description
Bit 7
MORA
$001F
6
5
Read: LVISTOP ROMSEC
Write:
Reset:
R
R
4
LVIRST LVIPWR
R
3
2
1
Bit 0
SSREC
COPRS
STOP
COPD
R
R
R
R
R
Unaffected by reset
Figure 10-1. Mask Option Register A (MORA)
LVISTOP — LVI Stop Mode Enable Bit
LVISTOP enables the LVI module in stop mode. See Low Voltage
Inhibit (LVI) on page 195.
1 = LVI enabled during stop mode
0 = LVI disabled during stop mode
ROMSEC — ROM Security Bit
ROMSEC enables the ROM security feature. Setting the ROMSEC bit
prevents access to the ROM contents.
1 = ROM security enabled
0 = ROM security disabled
LVIRST — LVI Reset Enable Bit
LVIRST enables the reset signal from the LVI module. See Low
Voltage Inhibit (LVI).
1 = LVI module resets enabled
0 = LVI module resets disabled
LVIPWR — LVI Power Enable Bit
LVIPWR enables the LVI module. See Low Voltage Inhibit (LVI).
1 = LVI module power enabled
0 = LVI module power disabled
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Freescale Semiconductor
Mask Options
SSREC — Short Stop Recovery Bit
SSREC enables the CPU to exit stop mode with a delay of 32
CGMXCLK cycles instead of a 4096 CGMXCLK cycle delay.
1 = STOP mode recovery after 32 CGMXCLK cycles
0 = STOP mode recovery after 4096 CGMXCLK cycles
If using an external crystal oscillator, the SSREC bit should not be set.
COPRS — COP Rate Select
COPRS is similar to COPL (please note that the logic is reversed) as
it determines the timeout period for the COP.
1 = COP timeout period is 213 — 24 CGMXCLK cycles.
0 = COP timeout period is 218 — 24 CGMXCLK cycles.
STOP — STOP Enable Bit
STOP enables the STOP instruction.
1 = STOP instruction enabled
0 = STOP instruction treated as illegal opcode
COPD — COP Disable Bit
COPD disables the COP module. See Computer Operating
Properly (COP).
1 = COP module disabled
0 = COP module enabled
NOTE:
Extra care should be taken when selecting MOR options since not all
HC08 family devices have the same options. In particular refer to the
appendix on differences of previous versions of MC68HC08AZ60. It is
the user’s responsibility to correctly define the mask option registers.
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Technical Data
Mask Options
169
Mask Options
Bit 7
MORB
$FE09
6
5
R
R
Read: EEDIVCLK
Write:
4
3
EEMONSEC
AZ60A
R
R
R
Reset:
2
1
Bit 0
Unaffected by reset
= Unimplemented
R
= Reserved
Figure 10-2. Mask Option Register B (MORB)
EEDIVCLK — EEPROM-1 and EEPROM-2 Timebase Dividers Clock
Select Bit
EEDIVCLK selects the reference clock source for the EEPROM-1 and
EEPROM-2 timebase dividers. See EEPROM-1 Timebase Divider
Register on page 74 and EEPROM-2 Timebase Divider Register
on page 94.
1 = CPU bus clock drives the EEPROM-1 and EEPROM-2
timebase dividers
0 = CGMXCLK drives the EEPROM-1 and EEPROM-2 timebase
dividers
EEMONSEC — EEPROM Read Protection in Monitor Mode Bit
When EEMONSEC is set, the entire EEPROM-1 and EEPROM-2
arrays cannot be acessed in monitor mode unless a valid security
code is entered.
1 = EEPROM-1 and EEPROM-2 read protection in monitor mode
enabled.
0 = EEPROM-1 and EEPROM-2 read protection in monitor mode
disabled.
AZ60A — Device Indicator (Not user-selectable)
This bit is set to a logic ’1’.
Extra care should be exercised when selecting mask option
registers since other HC08 family parts may have different options.
If in doubt, check with your local field applications representative.
Technical Data
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Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 11. Break Module
11.1 Contents
11.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
11.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171
11.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
11.4.1 Flag Protection During Break Interrupts . . . . . . . . . . . . 173
11.4.2 CPU During Break Interrupts . . . . . . . . . . . . . . . . . . . . . 174
11.4.3 TIM and PIT During Break Interrupts . . . . . . . . . . . . . . . 174
11.4.4 COP During Break Interrupts . . . . . . . . . . . . . . . . . . . . . 174
11.5 Break Module Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
11.5.1 Break Status and Control Register (BRKSCR) . . . . . . . 175
11.5.2 Break Address Registers (BRKH and BRKL) . . . . . . . . 176
11.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
11.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
11.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
11.2 Introduction
This section describes the break module. The break module can
generate a break interrupt which stops normal program flow at a defined
address in order to begin execution of a background program.
11.3 Features
Features of the break module include the following:
•
Accessible I/O registers during the break interrupt
•
CPU-generated break Interrupts
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Break Module
•
Software-generated break interrupts
•
COP disabling during break interrupts
11.4 Functional Description
When the internal address bus matches the value written in the break
address registers, the break module issues a breakpoint signal (BKPT)
to the SIM. The SIM then causes the CPU to load the instruction register
with a software interrupt instruction (SWI) after completion of the current
CPU instruction. The program counter vectors to $FFFC and $FFFD
($FEFC and $FEFD in monitor mode).
The following events can cause a break interrupt to occur:
•
A CPU-generated address (the address in the program counter)
matches the contents of the break address registers.
•
Software writes a ‘1’ to the BRKA bit in the break status and
control register (BRKSCR).
When a CPU-generated address matches the contents of the break
address registers, the break interrupt begins after the CPU completes its
current instruction. A return from interrupt instruction (RTI) in the break
routine ends the break interrupt and returns the MCU to normal
operation. Figure 11-1 shows the structure of the break module.
Technical Data
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Break Module
Freescale Semiconductor
Break Module
IAB[15:8]
BREAK ADDRESS REGISTER HIGH
8-BIT COMPARATOR
IAB[15:0]
CONTROL
BKPT
(TO SIM)
8-BIT COMPARATOR
BREAK ADDRESS REGISTER LOW
IAB[7:0]
Figure 11-1. Break Module Block Diagram
Table 11-1. Break I/O Register Summary
Register Name
Bit 7
6
5
4
3
2
1
Bit 0
Break Address Register High (BRKH)
Bit 15
14
13
12
11
10
9
Bit 8 $FE0C
Break Address Register Low (BRKL)
Bit 7
6
5
4
3
2
1
Bit 0 $FE0D
0
0
0
0
0
Break Status/Control Register (BRKSCR)
BRKE BRKA
Addr.
0
$FE0E
= Unimplemented
11.4.1 Flag Protection During Break Interrupts
The system integration module (SIM) controls whether or not module
status bits can be cleared during the break state. The BCFE bit in the
SIM break flag control register (SBFCR) enables software to clear status
bits during the break state. See System Integration Module (SIM) on
page 117, and the Break Interrupts subsection for each module.
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Technical Data
Break Module
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Break Module
11.4.2 CPU During Break Interrupts
The CPU starts a break interrupt by:
•
Loading the instruction register with the SWI instruction
•
Loading the program counter with $FFFC:$FFFD ($FEFC:$FEFD
in monitor mode)
The break interrupt begins after completion of the CPU instruction in
progress. If the break address register match occurs on the last cycle of
a CPU instruction, the break interrupt begins immediately.
11.4.3 TIM and PIT During Break Interrupts
A break interrupt stops the timer counter.
11.4.4 COP During Break Interrupts
The COP is disabled during a break interrupt when VHI is present on the
RST pin.
11.5 Break Module Registers
Three registers control and monitor operation of the break module:
•
Break status and control register (BRKSCR)
•
Break address register high (BRKH)
•
Break address register low (BRKL)
Technical Data
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Break Module
Freescale Semiconductor
Break Module
11.5.1 Break Status and Control Register (BRKSCR)
The break status and control register contains break module enable and
status bits.
BRKSCR
$FE0E
Bit 7
6
BRKE
BRKA
0
0
Read:
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0
0
0
0
Write:
Reset:
= Unimplemented
Figure 11-2. Break Status and Control Register (BRKSCR)
BRKE — Break Enable Bit
This read/write bit enables breaks on break address register matches.
BRKE is cleared by writing a ‘0’ to bit 7. Reset clears the BRKE bit.
1 = Breaks enabled on 16-bit address match
0 = Breaks disabled on 16-bit address match
BRKA — Break Active Bit
This read/write status and control bit is set when a break address
match occurs. Writing a ‘1’ to BRKA generates a break interrupt.
BRKA is cleared by writing a ‘0’ to it before exiting the break routine.
Reset clears the BRKA bit.
1 = Break address match
0 = No break address match
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Technical Data
Break Module
175
Break Module
11.5.2 Break Address Registers (BRKH and BRKL)
The break address registers contain the high and low bytes of the
desired breakpoint address. Reset clears the break address registers.
BRKH
$FE0C
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
14
13
12
11
10
9
Bit 8
0
0
0
0
0
0
0
0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
Read:
Write:
Reset:
BRKL
$FE0D
Read:
Write:
Reset:
Figure 11-3. Break Address Registers (BRKH and BRKL)
11.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low-powerconsumption standby modes.
11.6.1 Wait Mode
If enabled, the break module is active in wait mode. The SIM break wait
bit (BW) in the SIM break status register indicates whether wait was
exited by a break interrupt. If so, the user can modify the return address
on the stack by subtracting one from it. (See System Integration
Module (SIM) on page 117).
11.6.2 Stop Mode
The break module is inactive in stop mode. The STOP instruction does
not affect break module register states.
Technical Data
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Technical Data — MC68HC08AZ60A
Section 12. Monitor ROM (MON)
12.1 Contents
12.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
12.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177
12.4 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
12.4.1 Entering monitor mode . . . . . . . . . . . . . . . . . . . . . . . . . . 180
12.4.2 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
12.4.3 Echoing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
12.4.4 Break Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
12.4.4.1
Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183
12.4.5 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185
12.4.6 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
12.2 Introduction
This section describes the monitor ROM (MON08). The monitor ROM
allows complete testing of the MCU through a single-wire interface with
a host computer.
12.3 Features
Features of the monitor ROM include the following:
•
Normal User-Mode Pin Functionality
•
One Pin Dedicated to Serial Communication Between Monitor
ROM and Host Computer
•
Standard Mark/Space Non-Return-to-Zero (NRZ) Communication
with Host Computer
•
Up to 28.8K Baud Communication with Host Computer
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Technical Data
Monitor ROM (MON)
177
Monitor ROM (MON)
•
Execution of Code in RAM or ROM
•
EEPROM Programming
•
ROM Security (Read Protection)(1)
•
EEPROM Read Protection(1)
12.4 Functional description
The monitor ROM receives and executes commands from a host
computer. Figure 12-1 shows a sample circuit used to enter monitor
mode and communicate with a host computer via a standard RS-232
interface.
While simple monitor commands can access any memory address, the
MC68HC08AZ60A has optional ROM/EEPROM read protection
features to prevent external viewing of the contents of ROM/EEPROM
(see Mask Options on page 167). Proper procedures must be followed
to verify ROM/EEPROM content. Access to the ROM/EEPROM is
denied to unauthorized users of customer specified software with read
protection features enabled. See Security.
In monitor mode, the MCU can execute host-computer code in RAM
while all MCU pins except PTA0 retain normal operating mode functions.
All communication between the host computer and the MCU is through
the PTA0 pin. A level-shifting and multiplexing interface is required
between PTA0 and the host computer. PTA0 is used in a wired-OR
configuration and requires a pull-up resistor.
1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or
copying the ROM/EEPROM data difficult for unauthorized users
Technical Data
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Monitor ROM (MON)
Freescale Semiconductor
Monitor ROM (MON)
VDD
68HC08
10 kΩ
RST
0.1 µF
VHI
1 KΩ
IRQ
9.1V
VDDA
VDDA
CGMXFC
1
10 µF
10 µF
+
MC145407
0.1 µF
20
+
3
18
4
17
2
19
DB-25
2
5
16
3
6
15
OSC1
20 pF
+
+
10 µF
X1
4.9152 MHz
10 MΩ
OSC2
10 µF
20 pF
VSSA
VSS
VDD
VDD
0.1 µF
7
VDD
1
MC68HC125
2
3
6
5
4
7
NOTE: Position A — Bus clock = CGMXCLK ÷ 4 or CGMVCLK ÷ 4
Position B — Bus clock = CGMXCLK ÷ 2
VDD
14
10 kΩ
PTA0
VDD
10 kΩ
A
(See
NOTE.) B
PTC3
VDD
10 kΩ
PTC0
PTC1
Figure 12-1. Monitor Mode Circuit
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Technical Data
Monitor ROM (MON)
179
Monitor ROM (MON)
12.4.1 Entering monitor mode
Table 12-1 shows the pin conditions for entering monitor mode.
IRQ Pin
PTC0 Pin
PTC1 Pin
PTA0 Pin
PTC3 Pin
Table 12-1. Mode Selection
Mode
VHI(1)
1
0
1
1
Monitor
CGMXCLK
CGMVCLK
----------------------------- or ----------------------------2
2
CGMOUT
-------------------------2
VHI(1)
1
0
1
0
Monitor
CGMXCLK
CGMOUT
-------------------------2
CGMOUT
Bus
Frequency
1. For VHI, 5.0 Volt DC Electrical Characteristics on page 448, and Maximum Ratings on page 446.
Enter monitor mode by either
•
Executing a software interrupt instruction (SWI) or
•
Applying a ‘0’ and then a ‘1’ to the RST pin.
Once out of reset, the MCU waits for the host to send eight security bytes
(see Security on page 186). After the security bytes, the MCU sends a
break signal (10 consecutive ‘0’s) to the host computer, indicating that it
is ready to receive a command.
Monitor mode uses alternate vectors for reset, SWI, and break interrupt.
The alternate vectors are in the $FE page instead of the $FF page and
allow code execution from the internal monitor firmware instead of user
code. The COP module is disabled in monitor mode as long as VHI (see
Electrical Specifications on page 445), is applied to either the IRQ1 pin
or the RST pin. See System Integration Module (SIM) on page 117 for
more information on modes of operation.
NOTE:
Holding the PTC3 pin low when entering monitor mode causes a bypass
of a divide-by-two stage at the oscillator. The CGMOUT frequency is
equal to the CGMXCLK frequency, and the OSC1 input directly
generates internal bus clocks. In this case, the OSC1 signal must have
a 50% duty cycle at maximum bus frequency.
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Monitor ROM (MON)
Table 12-2 is a summary of the differences between user mode and
monitor mode.
Table 12-2. Mode Differences
Functions
Modes
COP
Reset
Vector
High
Reset
Vector
Low
Break
Vector
High
Break
Vector
Low
SWI
Vector
High
SWI
Vector
Low
User
Enabled
$FFFE
$FFFF
$FFFC
$FFFD
$FFFC
$FFFD
Monitor
Disabled(1)
$FEFE
$FEFF
$FEFC
$FEFD
$FEFC
$FEFD
1. If the high voltage (VHI) is removed from the IRQ and/or RESET pin while in monitor mode, the SIM asserts its COP enable output. The COP is enabled or disabled by the COPD bit in the configuration register. See 5.0 Volt DC Electrical Characteristics.
12.4.2 Data Format
Communication with the monitor ROM is in standard non-return-to-zero
(NRZ) mark/space data format. (See Figure 12-2 and Figure 12-3).
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
STOP
BIT
NEXT
START
BIT
Figure 12-2. Monitor Data Format
$A5
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BREAK
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
STOP
BIT
STOP
BIT
NEXT
START
BIT
NEXT
START
BIT
Figure 12-3. Sample Monitor Waveforms
The data transmit and receive rate can be anywhere up to 28.8 KBaud.
Transmit and receive baud rates must be identical.
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181
Monitor ROM (MON)
12.4.3 Echoing
The monitor ROM immediately echoes each received byte back to the
PTA0 pin for error checking, as shown in Figure 12-4.
SENT TO
MONITOR
READ
READ
ADDR. HIGH
ADDR. HIGH ADDR. LOW ADDR. LOW
DATA
ECHO
RESULT
Figure 12-4. Read Transaction
Any result of a command appears after the echo of the last byte of the
command.
12.4.4 Break Signal
A break signal is a start bit followed by nine low bits. This is shown in
Figure 12-4. When the monitor receives a break signal, it drives the
PTA0 pin high for the duration of two bits before echoing the break
signal.
MISSING STOP BIT
TWO-STOP-BIT DELAY BEFORE ZERO ECHO
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Figure 12-5. Break Transaction
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Monitor ROM (MON)
12.4.4.1 Commands
The monitor ROM uses the following commands:
•
READ (read memory)
•
WRITE (write memory)
•
IREAD (indexed read)
•
IWRITE (indexed write)
•
READSP (read stack pointer)
•
RUN (run user program)
Table 12-3. READ (Read Memory) Command
Description
Read byte from memory
Operand
Specifies 2-byte address in high byte:low byte order
Data returned
Returns contents of specified address
Opcode
$4A
Command sequence
SENT TO
MONITOR
READ
READ
ADDR. HIGH ADDR. HIGH ADDR. LOW
ADDR. LOW
ECHO
DATA
RESULT
Table 12-4. WRITE (Write Memory) Command
Description
Write byte to memory
Operand
Specifies 2-byte address in high byte:low byte order; low byte followed by data byte
Data returned
None
Opcode
$49
Command sequence
SENT TO
MONITOR
WRITE
WRITE
ADDR. HIGH
ADDR. HIGH ADDR. LOW
ADDR. LOW
DATA
DATA
ECHO
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Technical Data
Monitor ROM (MON)
183
Monitor ROM (MON)
Table 12-5. IREAD (Indexed Read) Command
Description
Read next 2 bytes in memory from last address accessed
Operand
Specifies 2-byte address in high byte:low byte order
Data returned
Returns contents of next two addresses
Opcode
$1A
Command sequence
SENT TO
MONITOR
IREAD
IREAD
DATA
DATA
RESULT
ECHO
Table 12-6. IWRITE (Indexed Write) Command
Description
Write to last address accessed + 1
Operand
Specifies single data byte
Data returned
None
Opcode
$19
Command sequence
SENT TO
MONITOR
IWRITE
IWRITE
DATA
DATA
ECHO
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Freescale Semiconductor
Monitor ROM (MON)
A sequence of IREAD or IWRITE commands can sequentially access a
block of memory over the full 64K byte memory map.
Table 12-7. READSP (Read Stack Pointer) Command
Description
Reads stack pointer
Operand
None
Data returned
Returns stack pointer in high byte:low byte order
Opcode
$0C
Command sequence
SENT TO
MONITOR
READSP
READSP
SP HIGH
SP LOW
RESULT
ECHO
Table 12-8. RUN (Run User Program) Command
Description
Executes RTI instruction
Operand
None
Data returned
None
Opcode
$28
Command sequence
SENT TO
MONITOR
RUN
RUN
ECHO
12.4.5 Baud Rate
The MC68HC08AZ60A features a monitor mode which is optimised to
operate with either a 4.9152MHz crystal clock source (or multiples of
4.9152MHz) or a 4MHz crystal (or multiples of 4MHz). This supports
designs which use the MSCAN08 module, which is generally clocked
from a 4MHz, 8MHz or 16MHz internal reference clock. The table below
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Technical Data
Monitor ROM (MON)
185
Monitor ROM (MON)
outlines the available baud rates for a range of crystals and how they can
match to a PC baud rate.
Baud rate
Closest PC baud PC
Error %
Clock freq
PTC3=0
PTC3=1
PTC3=0
PTC3=1
PTC3=0
PTC3=1
32kHz
57.97
28.98
57.6
28.8
0.64
0.63
1MHz
1811.59
905.80
1800
900
0.64
0.64
2MHz
3623.19
1811.59
3600
1800
0.64
0.64
4MHz
7246.37
3623.19
7200
3600
0.64
0.64
4.194MHz
7597.83
3798.91
7680
3840
1.08
1.08
4.9152MHz
8904.35
4452.17
8861
4430
0.49
0.50
8MHz
14492.72
7246.37
14400
7200
0.64
0.64
16MHz
28985.51
14492.75
28800
14400
0.64
0.64
Care should be taken when setting the baud rate since incorrect
baud rate setting can result in communications failure.
12.4.6 Security
Security features discourage unauthorized reading of ROM/EEPROM
locations while in monitor mode. The host can bypass the security
features at monitor mode entry by sending eight security bytes that
match the byte locations $FFF6–$FFFD. Locations $FFF6–$FFFD
contain user-defined data.
NOTE:
Do not leave locations $FFF6–$FFFD blank. For security reasons, enter
data at locations $FFF6–$FFFD even if they are not used for vectors.
During monitor mode entry, the MCU waits after the power-on reset for
the host to send the eight security bytes on pin PA0.
If the received bytes match those at locations $FFF6–$FFFD, the host
bypasses the security features and can read all ROM/EEPROM
locations and execute code from ROM. Security remains bypassed until
a power-on reset occurs. After the host bypasses security, any reset
other than a power-on reset requires the host to send another eight
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Monitor ROM (MON)
bytes. If the reset was not a power-on reset, security remains bypassed
regardless of the data that the host sends.
If the received bytes do not match the data at locations $FFF6–$FFFD,
the host fails to bypass the security features. The MCU remains in
monitor mode, but reading ROM/EEPROM locations returns undefined
data, and trying to execute code from ROM causes an illegal address
reset. After the host fails to bypass security, any reset other than a
power-on reset causes an endless loop of illegal address resets.
After receiving the eight security bytes from the host, the MCU transmits
a break character signalling that it is ready to receive a command.
NOTE:
The MCU does not transmit a break character until after the host sends
the eight security bytes.
VDD
4096 + 32 CGMXCLK CYCLES
RST
Command
Byte 8
Byte 2
FROM HOST
Byte 1
24 BUS CYCLES (MINIMUM)
PA0
4
Break
2
1
Command Echo
NOTE: 1 = Echo delay (2 bit times)
2 = Data return delay (2 bit times)
4 = Wait 1 bit time before sending next byte.
1
Byte 8 Echo
Byte 1 Echo
FROM MCU
1
Byte 2 Echo
4
1
Figure 12-6. Monitor Mode Entry Timing
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Technical Data
Monitor ROM (MON)
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Monitor ROM (MON)
Technical Data
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Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 13. Computer Operating Properly (COP)
13.1 Contents
13.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
13.3
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
13.4 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
13.4.1 CGMXCLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
13.4.2 STOP Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
13.4.3 COPCTL Write. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .192
13.4.4 Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
13.4.5 Internal Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
13.4.6 Reset Vector Fetch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
13.4.7 COPD (COP Disable) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
13.4.8 COPRS (COP Rate Select) . . . . . . . . . . . . . . . . . . . . . . . . 192
13.5
COP Control Register (COPCTL). . . . . . . . . . . . . . . . . . . . . 193
13.6
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
13.7
Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
13.8 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
13.8.1 WAIT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
13.8.2 STOP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
13.9
COP Module During Break Interrupts . . . . . . . . . . . . . . . . . 194
13.2 Introduction
This section describes the computer operating properly (COP) module,
a free-running counter that generates a reset if allowed to overflow. The
COP module helps software recover from runaway code. COP resets
can be prevented by periodically clearing the COP counter.
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Computer Operating Properly (COP)
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Computer Operating Properly (COP)
13.3 Functional Description
Figure 13-1 shows the structure of the COP module.
12-BIT COP PRESCALER
STOP INSTRUCTION
INTERNAL RESET SOURCES
RESET VECTOR FETCH
CLEAR STAGES 4–12
CLEAR ALL STAGES
CGMXCLK
COPCTL WRITE
RESET
RESET STATUS
REGISTER
6-BIT COP COUNTER
COPD FROM MORA
RESET
CLEAR COP
COUNTER
COPCTL WRITE
COPRS FROM MORA
Figure 13-1. COP Block Diagram
Table 13-1. COP I/O Register Summary
Register Name
Bit 7
6
5
4
COP Control Register (COPCTL)
3
2
1
Bit 0
Addr.
$FFFF
The COP counter is a free-running 6-bit counter preceded by a12-bit
prescaler. If not cleared by software, the COP counter overflows and
generates an asynchronous reset after 213 – 24, or 218 – 24 CGMXCLK
cycles, depending on the state of the COP rate select bit, COPRS in
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Computer Operating Properly (COP)
MORA. When COPRS = 0, a 4.9152 MHz crystal, gives a COP timeout
period of 53.3ms. Writing any value to location $FFFF before overflow
occurs prevents a COP reset by clearing the COP counter and stages 4
through 12 of the prescaler.
NOTE:
Service the COP immediately after reset and before entering or after
exiting stop mode to guarantee the maximum time before the first COP
counter overflow.
A COP reset pulls the RST pin low for 32 CGMXCLK cycles and sets the
COP bit in the SIM reset status register (SRSR). See SIM Reset Status
Register (SRSR).
In monitor mode, the COP is disabled if the RST pin or the IRQ pin is held
at VHi. During the break state, VHi on the RST pin disables the COP.
NOTE:
Place COP clearing instructions in the main program and not in an
interrupt subroutine. Such an interrupt subroutine could keep the COP
from generating a reset even while the main program is not working
properly.
13.4 I/O Signals
The following paragraphs describe the signals shown in Figure 13-1.
13.4.1 CGMXCLK
CGMXCLK is the crystal oscillator output signal. The CGMXCLK
frequency is equal to the crystal frequency.
13.4.2 STOP Instruction
The STOP instruction clears the COP prescaler.
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Technical Data
Computer Operating Properly (COP)
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Computer Operating Properly (COP)
13.4.3 COPCTL Write
Writing any value to the COP control register (COPCTL) (see COP
Control Register (COPCTL) on page 193), clears the COP counter and
clears bits 12 – 4 of the COP prescaler. Reading the COP control
register returns the reset vector.
13.4.4 Power-On Reset
The power-on reset (POR) circuit clears the COP prescaler 4096
CGMXCLK cycles after power-up.
13.4.5 Internal Reset
An internal reset clears the COP prescaler and the COP counter.
13.4.6 Reset Vector Fetch
A reset vector fetch occurs when the vector address appears on the data
bus. A reset vector fetch clears the COP prescaler.
13.4.7 COPD (COP Disable)
The COPD signal reflects the state of the COP disable bit (COPD) in the
mask option register (MORA). See Mask Options.
13.4.8 COPRS (COP Rate Select)
The COPRS signal reflects the state of the COP rate select bit, COPRS
in the MORA register (see Figure 10-1 on page 168).
Technical Data
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Computer Operating Properly (COP)
13.5 COP Control Register (COPCTL)
The COP control register is located at address $FFFF and overlaps the
reset vector. Writing any value to $FFFF clears the COP counter and
starts a new timeout period. Reading location $FFFF returns the low
byte of the reset vector.
Bit 7
COPCTL
$FFFF
6
5
4
3
Read:
Low byte of reset vector
Write:
Clear COP counter
Reset:
Unaffected by reset
2
1
Bit 0
Figure 13-2. COP Control Register (COPCTL)
13.6 Interrupts
The COP does not generate CPU interrupt requests.
13.7 Monitor Mode
The COP is disabled in monitor mode when VHI is present on the IRQ pin
or on the RST pin.
13.8 Low-Power Modes
The WAIT and STOP instructions put the MCU in low-powerconsumption standby modes.
13.8.1 WAIT Mode
The COP continues to operate during WAIT mode. To prevent a COP
reset during WAIT mode, the COP counter should be cleared
periodically in a CPU interrupt routine.
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Technical Data
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Computer Operating Properly (COP)
13.8.2 STOP Mode
STOP mode turns off the CGMXCLK input to the COP and clears the
COP prescaler. The COP should be serviced immediately before
entering or after exiting STOP mode to ensure a full COP timeout period
after entering or exiting STOP mode.
The STOP bit in the mask option register (MOR) enables the STOP
instruction. To prevent inadvertently turning off the COP with a STOP
instruction, the STOP instruction should be disabled by programming the
STOP bit to ‘0’.
13.9 COP Module During Break Interrupts
The COP is disabled during a break interrupt when VHI is present on the
RST pin.
Technical Data
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Technical Data — MC68HC08AZ60A
Section 14. Low Voltage Inhibit (LVI)
14.1 Contents
14.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
14.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196
14.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
14.4.1 Polled LVI Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
14.4.2 Forced Reset Operation. . . . . . . . . . . . . . . . . . . . . . . . . . 197
14.4.3 False Reset Protection. . . . . . . . . . . . . . . . . . . . . . . . . . .198
14.5
LVI Status Register (LVISR). . . . . . . . . . . . . . . . . . . . . . . . . 198
14.6
LVI Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
14.7 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
14.7.1 WAIT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
14.7.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
14.2 Introduction
This section describes the low-voltage inhibit module, which monitors
the voltage on the VDD pin and can force a reset when the VDD voltage
falls to the LVI trip voltage.
Note that the LVI feature is intended to provide the safe shutdown
of the microcontroller and thus protection of related circuitry prior
to any application VDD voltage collapsing completely to an unsafe
level. Is is not intended that users operate the microcontroller at
lower than the specified operating voltage, VDD.
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Technical Data
Low Voltage Inhibit (LVI)
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Low Voltage Inhibit (LVI)
14.3 Features
Features of the LVI module include the following:
NOTE:
•
Programmable LVI reset
•
Programmable power consumption
•
Digital filtering of VDD pin level
If a low voltage interrupt (LVI) occurs during programming of EEPROM
memory, then adequate programming time may not have been allowed
to ensure the integrity and retention of the data. It is the responsibility of
the user to ensure that in the event of an LVI any addresses being
programmed receive specification programming conditions.
14.4 Functional Description
Figure 14-1 shows the structure of the LVI module. The LVI is enabled
out of reset. The LVI module contains a bandgap reference circuit and
comparator. The LVI power bit, LVIPWR, enables the LVI to monitor VDD
voltage. The LVI reset bit, LVIRST, enables the LVI module to generate
a reset when VDD falls below a voltage, LVITRIPF, and remains at or below
that level for 9 or more consecutive CPU cycles.
Note that short VDD spikes may not trip the LVI. It is the user’s
responsibility to ensure a clean VDD signal within the specified
operating voltage range if normal microcontroller operation is to be
guaranteed.
LVISTOP enables the LVI module during stop mode. This will ensure
when the STOP instruction is implemented the LVI will continue to
monitor the voltage level on VDD.
LVIPWR, LVIRST and LVISTOP are mask options. See Mask Options
on page 167. Once an LVI reset occurs, the MCU remains in reset until
VDD rises above a voltage, LVITRIPR. VDD must be above LVITRIPR for only
one CPU cycle to bring the MCU out of reset. The output of the
comparator controls the state of the LVIOUT flag in the LVI status
register (LVISR).
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Low Voltage Inhibit (LVI)
An LVI reset also drives the RST pin low to provide low-voltage
protection to external peripheral devices.
VDD
LVIPWR
FROM MORA
FROM MORA
CPU CLOCK
LOW VDD
DETECTOR
LVIRST
VDD
DIGITAL FILTER
VDD > LVITRIP = 0
VDD < LVITRIP = 1
LVI RESET
Stop Mode
Filter Bypass
ANLGTRIP
LVIOUT
LVISTOP
FROM MORA
Figure 14-1. LVI Module Block Diagram
Table 14-1. LVI I/O Register Summary
Register Name
Bit 7
6
5
4
LVI Status Register (LVISR) LVIOUT
3
2
1
Bit 0
Addr.
$FE0F
= Unimplemented
14.4.1 Polled LVI Operation
In applications that can operate at VDD levels below the LVITRIPF level,
software can monitor VDD by polling the LVIOUT bit. In the mask option
register, the LVIPWR bit must be at logic ‘1’ to enable the LVI module
and the LVIRST bit must be at logic ‘0’ to disable LVI resets.
14.4.2 Forced Reset Operation
In applications that require VDD to remain above the LVITRIPF level,
enabling LVI resets allows the LVI module to reset the MCU when VDD
falls to the LVITRIPF level and remains at or below that level for 9 or more
consecutive CPU cycles. In the mask option register, the LVIPWR and
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Technical Data
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Low Voltage Inhibit (LVI)
LVIRST bits must be at ‘1’ to enable the LVI module and to enable LVI
resets.
14.4.3 False Reset Protection
The VDD pin level is digitally filtered to reduce false resets due to power
supply noise. In order for the LVI module to reset the MCU,VDD must
remain at or below the LVITRIPF level for 9 or more consecutive CPU
cycles. VDD must be above LVITRIPR for only one CPU cycle to bring the
MCU out of reset.
14.5 LVI Status Register (LVISR)
The LVI status register flags VDD voltages below the LVITRIPF level.
Bit 7
LVISR
$FE0F
Read: LVIOUT
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Write:
Reset:
0
= Unimplemented
Figure 14-2. LVI Status Register (LVISR)
LVIOUT — LVI Output Bit
This read-only flag becomes set when VDD falls below the LVITRIPF
voltage for 32-40 CGMXCLK cycles. (See Table 14-2). Reset clears
the LVIOUT bit.
Technical Data
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Freescale Semiconductor
Low Voltage Inhibit (LVI)
Table 14-2. LVIOUT Bit Indication
VDD
at level:
for number of CGMXCLK
cycles:
LVIOUT
VDD > LVITRIPR
ANY
0
VDD < LVITRIPF
< 32 CGMXCLK cycles
0
VDD < LVITRIPF
between 32 & 40 CGMXCLK
cycles
0 or 1
VDD < LVITRIPF
> 40 CGMXCLK cycles
1
LVITRIPF < VDD < LVITRIPR
ANY
Previous Value
14.6 LVI Interrupts
The LVI module does not generate interrupt requests.
14.7 Low-Power Modes
The WAIT instruction puts the MCU in low-power-consumption standby
mode.
14.7.1 WAIT Mode
When the LVIPWR mask option is programmed to ‘1’, the LVI module is
active after a WAIT instruction.
When the LVIRST mask option is programmed to ‘1’, the LVI module can
generate a reset and bring the MCU out of WAIT mode.
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Freescale Semiconductor
Technical Data
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Low Voltage Inhibit (LVI)
14.7.2 Stop Mode
With LVISTOP=1 and LVIPWR=1 in the MORA register, the LVI module
will be active after a STOP instruction. Because CPU clocks are disabled
during stop mode, the LVI trip must bypass the digital filter to generate a
reset and bring the MCU out of stop.
With the LVIPWR bit in the MORA register at a logic 1 and the LVISTOP
bit at a logic 0, the LVI module will be inactive after a STOP instruction.
Technical Data
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Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 15. External Interrupt Module (IRQ)
15.1 Contents
15.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
15.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
15.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
15.4.1 IRQ Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
15.5
IRQ Module During Break Interrupts . . . . . . . . . . . . . . . . . 206
15.6
IRQ Status and Control Register (ISCR). . . . . . . . . . . . . . . 206
15.2 Introduction
The IRQ module provides the nonmaskable interrupt input.
15.3 Features
Features of the IRQ module include the following:
•
Dedicated external interrupt pins (IRQ)
•
IRQ interrupt control bit
•
Hysteresis buffer
•
Programmable edge-only or edge and level interrupt sensitivity
•
Automatic interrupt acknowledge
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External Interrupt Module (IRQ)
201
External Interrupt Module (IRQ)
15.4 Functional Description
A ‘0’ applied to any of the external interrupt pins can latch a CPU
interrupt request. Figure 15-1 shows the structure of the IRQ module.
Interrupt signals on the IRQ pin are latched into the IRQ latch. An
interrupt latch remains set until one of the following occurs:
•
Vector fetch — a vector fetch automatically generates an interrupt
acknowledge signal which clears the latch that caused the vector
fetch.
•
Software clear — software can clear an interrupt latch by writing
to the appropriate acknowledge bit in the interrupt status and
control register (ISCR). Writing a logic ‘1’ to the ACK bit clears the
IRQ latch.
•
Reset — a reset automatically clears the interrupt latch.
INTERNAL ADDRESS BUS
ACK
TO CPU FOR
BIL/BIH
INSTRUCTIONS
VECTOR
FETCH
DECODER
VDD
IRQF
D
CLR
Q
SYNCHRONIZER
CK
IRQ
IRQ
INTERRUPT
REQUEST
IRQ
LATCH
IMASK
MODE
HIGH
VOLTAGE
DETECT
TO MODE
SELECT
LOGIC
Figure 15-1. IRQ Module Block Diagram
The external interrupt pin is falling-edge-triggered and is softwareconfigurable to be both falling-edge and low-level-triggered. The MODE
bit in the ISCR controls the triggering sensitivity of the IRQ pin.
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Freescale Semiconductor
External Interrupt Module (IRQ)
When an interrupt pin is edge-triggered only, the interrupt latch remains
set until a vector fetch, software clear, or reset occurs.
When an interrupt pin is both falling-edge and low-level-triggered, the
interrupt latch remains set until both of the following occur:
•
Vector fetch or software clear
•
Return of the interrupt pin to ‘1’
The vector fetch or software clear may occur before or after the interrupt
pin returns to ‘1’. As long as the pin is low, the interrupt request remains
pending. A reset will clear the latch and the MODE control bit, thereby
clearing the interrupt even if the pin stays low.
Table 15-1. IRQ I/O Register Summary
Register Name
IRQ Status/Control Register (ISCR)
Bit 7
6
5
4
3
2
Read:
0
0
0
0
IRQF
0
Write:
R
R
R
R
R
ACK
R
1
IMASK
Bit 0
Addr.
MODE $001A
= Reserved
When set, the IMASK bit in the ISCR masks all external interrupt
requests. A latched interrupt request is not presented to the interrupt
priority logic unless the corresponding IMASK bit is clear.
NOTE:
The interrupt mask (I) in the condition code register (CCR) masks all
interrupt requests, including external interrupt requests. See Figure 152.
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External Interrupt Module (IRQ)
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External Interrupt Module (IRQ)
.
FROM RESET
YES
I BIT SET?
NO
INTERRUPT?
YES
NO
STACK CPU REGISTERS.
SET I BIT.
LOAD PC WITH INTERRUPT VECTOR.
FETCH NEXT
INSTRUCTION.
SWI
INSTRUCTION?
YES
NO
RTI
INSTRUCTION?
YES
UNSTACK CPU REGISTERS.
NO
EXECUTE INSTRUCTION.
Figure 15-2. IRQ Interrupt Flowchart
Technical Data
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Freescale Semiconductor
External Interrupt Module (IRQ)
15.4.1 IRQ Pin
A ‘0’ on the IRQ pin can latch an interrupt request into the IRQ latch. A
vector fetch, software clear, or reset clears the IRQ latch.
If the MODE bit is set, the IRQ pin is both falling-edge-sensitive and lowlevel-sensitive. With MODE set, both of the following actions must occur
to clear the IRQ latch:
•
Vector fetch or software clear — a vector fetch generates an
interrupt acknowledge signal to clear the latch. Software may
generate the interrupt acknowledge signal by writing a logic ‘1’ to
the ACK bit in the interrupt status and control register (ISCR). The
ACK bit is useful in applications that poll the IRQ pin and require
software to clear the IRQ latch. Writing to the ACK bit can also
prevent spurious interrupts due to noise. Setting ACK does not
affect subsequent transitions on the IRQ pin. A falling edge that
occurs after writing to the ACK bit latches another interrupt
request. If the IRQ mask bit, IMASK, is clear, the CPU loads the
program counter with the vector address at locations $FFFA and
$FFFB.
•
Return of the IRQ pin to logic ‘1’ — as long as the IRQ pin is at
logic ‘0’, the IRQ latch remains set.
The vector fetch or software clear and the return of the IRQ pin to logic
‘1’ may occur in any order. The interrupt request remains pending as
long as the IRQ pin is at logic ‘0’. A reset will clear the latch and the
MODE control bit, thereby clearing the interrupt even if the pin stays low.
If the MODE bit is clear, the IRQ pin is falling-edge-sensitive only. With
MODE clear, a vector fetch or software clear immediately clears the IRQ
latch.
The IRQF bit in the ISCR register can be used to check for pending
interrupts. The IRQF bit is not affected by the IMASK bit, which makes it
useful in applications where polling is preferred.
The BIH or BIL instruction is used to read the logic level on the IRQ pin.
NOTE:
When using the level-sensitive interrupt trigger, false interrupts can be
avoided by masking interrupt requests in the interrupt routine.
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External Interrupt Module (IRQ)
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External Interrupt Module (IRQ)
15.5 IRQ Module During Break Interrupts
The system integration module (SIM) controls whether the IRQ interrupt
latch can be cleared during the break state. The BCFE bit in the SIM
break flag control register (SBFCR) enables software to clear the latches
during the break state. See SIM Break Flag Control Register
(SBFCR).
To allow software to clear the IRQ latch during a break interrupt, write a
logic ’1’ to the BCFE bit. If a latch is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect the latches during the break state, write a logic ‘0’ to the BCFE
bit. With BCFE at logic ‘0’ (its default state), writing to the ACK bit in the
IRQ status and control register during the break state has no effect on
the IRQ latch.
15.6 IRQ Status and Control Register (ISCR)
The IRQ status and control register (ISCR) controls and monitors
operation of the IRQ module. The ISCR performs the following functions:
•
Indicates the state of the IRQ interrupt flag
•
Clears the IRQ interrupt latch
•
Masks IRQ interrupt requests
•
Controls triggering sensitivity of the IRQ interrupt pin
Address:
$001A
Bit 7
6
5
4
3
2
Read:
0
0
0
0
IRQF
0
Write:
R
R
R
R
R
ACK
Reset:
0
0
0
0
0
0
R
1
Bit 0
IMASK
MODE
0
0
= Reserved
Figure 15-3. IRQ Status and Control Register (ISCR)
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External Interrupt Module (IRQ)
IRQF — IRQ Flag Bit
This read-only status bit is high when the IRQ interrupt is pending.
1 = IRQ interrupt pending
0 = IRQ interrupt not pending
ACK — IRQ Interrupt Request Acknowledge Bit
Writing a logic ‘1’ to this write-only bit clears the IRQ latch. ACK
always reads as logic ‘0’. Reset clears ACK.
IMASK — IRQ Interrupt Mask Bit
Writing a logic ‘1’ to this read/write bit disables IRQ interrupt requests.
Reset clears IMASK.
1 = IRQ interrupt requests disabled
0 = IRQ interrupt requests enabled
MODE — IRQ Edge/Level Select Bit
This read/write bit controls the triggering sensitivity of the IRQ pin.
Reset clears MODE.
1 = IRQ interrupt requests on falling edges and low levels
0 = IRQ interrupt requests on falling edges only
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External Interrupt Module (IRQ)
Technical Data
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Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 16. Serial Communications Interface (SCI)
16.1 Contents
16.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
16.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .210
16.4
Pin Name Conventions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
16.5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
16.5.1 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
16.5.2 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
16.5.2.1
Character Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
16.5.2.2
Character Transmission . . . . . . . . . . . . . . . . . . . . . . .214
16.5.2.3
Break Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
16.5.2.4
Idle Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
16.5.2.5
Inversion of Transmitted Output . . . . . . . . . . . . . . . . 219
16.5.2.6
Transmitter Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 219
16.5.3 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
16.5.3.1
Character Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
16.5.3.2
Character Reception . . . . . . . . . . . . . . . . . . . . . . . . . . 222
16.5.3.3
Data Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
16.5.3.4
Framing Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
16.5.3.5
Baud Rate Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . 225
16.5.3.6
Receiver Wakeup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
16.5.3.7
Receiver Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
16.5.3.8
Error Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .228
16.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
16.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
16.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
16.7
SCI During Break Module Interrupts. . . . . . . . . . . . . . . . . . 230
16.8 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
16.8.1 PTE0/TxD (Transmit Data) . . . . . . . . . . . . . . . . . . . . . . . . 231
16.8.2 PTE1/RxD (Receive Data) . . . . . . . . . . . . . . . . . . . . . . . . 231
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Serial Communications Interface (SCI)
16.9 I/O Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .231
16.9.1 SCI Control Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . .231
16.9.2 SCI Control Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . .234
16.9.3 SCI Control Register 3 . . . . . . . . . . . . . . . . . . . . . . . . . . .237
16.9.4 SCI Status Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
16.9.5 SCI Status Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
16.9.6 SCI Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
16.9.7 SCI Baud Rate Register . . . . . . . . . . . . . . . . . . . . . . . . . . 245
16.2 Introduction
The SCI allows asynchronous communications with peripheral devices
and other MCUs.
16.3 Features
The SCI module’s features include:
•
Full Duplex Operation
•
Standard Mark/Space Non-Return-to-Zero (NRZ) Format
•
32 Programmable Baud Rates
•
Programmable 8-Bit or 9-Bit Character Length
•
Separately Enabled Transmitter and Receiver
•
Separate Receiver and Transmitter CPU Interrupt Requests
•
Programmable Transmitter Output Polarity
•
Two Receiver Wakeup Methods:
– Idle Line Wakeup
– Address Mark Wakeup
•
Interrupt-Driven Operation with Eight Interrupt Flags:
– Transmitter Empty
– Transmission Complete
– Receiver Full
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Serial Communications Interface (SCI)
– Idle Receiver Input
– Receiver Overrun
– Noise Error
– Framing Error
– Parity Error
•
Receiver Framing Error Detection
•
Hardware Parity Checking
•
1/16 Bit-Time Noise Detection
16.4 Pin Name Conventions
The generic names of the SCI input/output (I/O) pins are:
•
RxD (receive data)
•
TxD (transmit data)
SCI I/O lines are implemented by sharing parallel I/O port pins. The full
name of an SCI input or output reflects the name of the shared port pin.
Table 16-1 shows the full names and the generic names of the SCI I/O
pins.The generic pin names appear in the text of this section.
Table 16-1. Pin Name Conventions
Generic Pin Names
RxD
TxD
Full Pin Names
PTE1/RxD
PTE0/TxD
16.5 Functional Description
Figure 16-1 shows the structure of the SCI module. The SCI allows fullduplex, asynchronous, NRZ serial communication between the MCU
and remote devices, including other MCUs. The transmitter and receiver
of the SCI operate independently, although they use the same baud rate
generator. During normal operation, the CPU monitors the status of the
SCI, writes the data to be transmitted, and processes received data.
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Technical Data
Serial Communications Interface (SCI)
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Serial Communications Interface (SCI)
INTERNAL BUS
ERROR
INTERRUPT
CONTROL
RECEIVE
SHIFT REGISTER
RxD
SCI DATA
REGISTER
RECEIVER
INTERRUPT
CONTROL
TRANSMITTER
INTERRUPT
CONTROL
SCI DATA
REGISTER
TRANSMIT
SHIFT REGISTER
TxD
TXINV
SCTIE
R8
TCIE
T8
SCRIE
ILIE
TE
SCTE
RE
TC
RWU
SBK
SCRF
OR
ORIE
IDLE
NF
NEIE
FE
FEIE
PE
PEIE
LOOPS
LOOPS
RECEIVE
CONTROL
WAKEUP
CONTROL
ENSCI
ENSCI
TRANSMIT
CONTROL
FLAG
CONTROL
BKF
M
RPF
WAKE
ILTY
CGMXCLK
÷4
PRESCALER
BAUD RATE
GENERATOR
÷ 16
PEN
PTY
DATA SELECTION
CONTROL
Figure 16-1. SCI Module Block Diagram
Technical Data
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Serial Communications Interface (SCI)
Register Name
Bit 7
Read:
LOOPS
SCI Control Register 1 (SCC1) Write:
Reset:
0
Read:
SCTIE
SCI Control Register 2 (SCC2) Write:
Reset:
0
Read:
R8
SCI Control Register 3 (SCC3) Write:
Reset:
U
Read: SCTE
SCI Status Register 1 (SCS1) Write:
Reset:
1
Read:
0
SCI Status Register 2 (SCS2) Write:
Reset:
0
Read:
R7
SCI Data Register (SCDR) Write:
T7
Reset:
Read:
0
SCI Baud Rate Register (SCBR) Write:
Reset:
0
6
5
4
3
2
1
Bit 0
ENSCI
TXINV
M
WAKE
ILTY
PEN
PTY
0
0
0
0
0
0
0
TCIE
SCRIE
ILIE
TE
RE
RWU
SBK
0
0
0
0
0
0
0
T8
R
R
ORIE
NEIE
FEIE
PEIE
U
TC
0
SCRF
0
IDLE
0
OR
0
NF
0
FE
0
PE
1
0
0
0
0
0
0
0
0
0
0
BKF
0
RPF
0
R6
T6
0
R5
T5
0
R2
T2
0
R1
T1
0
R0
T0
0
0
0
0
R4
R3
T4
T3
Unaffected by Reset
SCP1
SCP0
R
SCR2
SCR1
SCR0
0
0
0
0
0
0
= Unimplemented
U = Unaffected
R = Reserved
Figure 16-2. SCI I/O Register Summary
Table 16-2. SCI I/O Register Address Summary
Register
SCC1
SCC2
SCC3
SCS1
SCS2
SCDR
SCBR
Address
$0013
$0014
$0015
$0016
$0017
$0018
$0019
16.5.1 Data Format
The SCI uses the standard non-return-to-zero mark/space data format
illustrated in Figure 16-3.
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Serial Communications Interface (SCI)
8-BIT DATA FORMAT
(BIT M IN SCC1 CLEAR)
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
PARITY
OR DATA
BIT
BIT 6
9-BIT DATA FORMAT
(BIT M IN SCC1 SET)
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
STOP
BIT
NEXT
START
BIT
PARITY
OR DATA
BIT
BIT 7
BIT 8 STOP
BIT
NEXT
START
BIT
Figure 16-3. SCI Data Formats
16.5.2 Transmitter
Figure 16-4 shows the structure of the SCI transmitter.
16.5.2.1 Character Length
The transmitter can accommodate either 8-bit or 9-bit data. The state of
the M bit in SCI control register 1 (SCC1) determines character length.
When transmitting 9-bit data, bit T8 in SCI control register 3 (SCC3) is
the ninth bit (bit 8).
16.5.2.2 Character Transmission
During an SCI transmission, the transmit shift register shifts a character
out to the TxD pin. The SCI data register (SCDR) is the write-only buffer
between the internal data bus and the transmit shift register. To initiate
an SCI transmission:
1. Enable the SCI by writing a logic 1 to the enable SCI bit (ENSCI)
in SCI control register 1 (SCC1).
2. Enable the transmitter by writing a logic 1 to the transmitter enable
bit (TE) in SCI control register 2 (SCC2).
3. Clear the SCI transmitter empty bit (SCTE) by first reading SCI
status register 1 (SCS1) and then writing to the SCDR.
4. Repeat step 3 for each subsequent transmission.
At the start of a transmission, transmitter control logic automatically
loads the transmit shift register with a preamble of logic 1s. After the
Technical Data
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Serial Communications Interface (SCI)
preamble shifts out, control logic transfers the SCDR data into the
transmit shift register. A logic 0 start bit automatically goes into the least
significant bit position of the transmit shift register. A logic 1 stop bit goes
into the most significant bit position.
The SCI transmitter empty bit, SCTE, in SCS1 becomes set when the
SCDR transfers a byte to the transmit shift register. The SCTE bit
indicates that the SCDR can accept new data from the internal data bus.
If the SCI transmit interrupt enable bit, SCTIE, in SCC2 is also set, the
SCTE bit generates a transmitter CPU interrupt request.
When the transmit shift register is not transmitting a character, the TxD
pin goes to the idle condition, logic 1. If at any time software clears the
ENSCI bit in SCI control register 1 (SCC1), the transmitter and receiver
relinquish control of the port E pins.
MC68HC08AZ60A — Rev 2.1
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Technical Data
Serial Communications Interface (SCI)
215
Serial Communications Interface (SCI)
INTERNAL BUS
÷ 16
SCI DATA REGISTER
SCP1
11-BIT
TRANSMIT
SHIFT REGISTER
STOP
CGMXCLK
BAUD
DIVIDER
SCP0
SCR1
H
SCR2
8
7
6
5
4
3
2
START
PRESCALER
÷4
1
0
L
TxD
MSB
TXINV
PARITY
GENERATION
T8
BREAK
(ALL ZEROS)
PTY
PREAMBLE
(ALL ONES)
PEN
SHIFT ENABLE
M
LOAD FROM SCDR
TRANSMITTER CPU INTERRUPT REQUEST
SCR0
TRANSMITTER
CONTROL LOGIC
SCTE
SCTE
SCTIE
TC
TCIE
SBK
LOOPS
SCTIE
ENSCI
TC
TE
TCIE
Figure 16-4. SCI Transmitter
Technical Data
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Serial Communications Interface (SCI)
Register Name
Bit 7
6
5
4
3
2
1
Bit 0
LOOPS
ENSCI
TXINV
M
WAKE
ILTY
PEN
PTY
0
0
0
0
0
0
0
0
SCTIE
TCIE
SCRIE
ILIE
TE
RE
RWU
SBK
Reset:
0
0
0
0
0
0
0
0
Read:
R8
T8
R
R
ORIE
NEIE
FEIE
PEIE
Read:
SCI Control Register 1 (SCC1) Write:
Reset:
Read:
SCI Control Register 2 (SCC2) Write:
SCI Control Register 3 (SCC3) Write:
Reset:
U
U
0
0
0
0
0
0
Read:
SCTE
TC
SCRF
IDLE
OR
NF
FE
PE
Reset:
1
1
0
0
0
0
0
0
Read:
R7
R6
R5
R4
R3
R2
R1
R0
SCI Data Register (SCDR) Write:
T7
T6
T5
T4
T3
T2
T1
T0
SCI Status Register 1 (SCS1) Write:
Reset:
Read:
Unaffected by Reset
0
0
0
0
SCI Baud Rate Register (SCBR) Write:
Reset:
SCP1
SCP0
R
SCR2
SCR1
SCR0
0
0
0
0
0
0
= Unimplemented
U = Unaffected
R = Reserved
Figure 16-5. SCI Transmitter I/O Register Summary
Table 16-3. SCI Transmitter I/O Address Summary
Register
SCC1
SCC2
SCC3
SCS1
SCDR
SCBR
Address
$0013
$0014
$0015
$0016
$0018
$0019
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Serial Communications Interface (SCI)
16.5.2.3 Break Characters
Writing a logic 1 to the send break bit, SBK, in SCC2 loads the transmit
shift register with a break character. A break character contains all logic
0s and has no start, stop, or parity bit. Break character length depends
on the M bit in SCC1. As long as SBK is at logic 1, transmitter logic
continuously loads break characters into the transmit shift register. After
software clears the SBK bit, the shift register finishes transmitting the
last break character and then transmits at least one logic 1. The
automatic logic 1 at the end of a break character guarantees the
recognition of the start bit of the next character.
The SCI recognizes a break character when a start bit is followed by
eight or nine logic 0 data bits and a logic 0 where the stop bit should be.
Receiving a break character has the following effects on SCI registers:
•
Sets the framing error bit (FE) in SCS1
•
Sets the SCI receiver full bit (SCRF) in SCS1
•
Clears the SCI data register (SCDR)
•
Clears the R8 bit in SCC3
•
Sets the break flag bit (BKF) in SCS2
•
May set the overrun (OR), noise flag (NF), parity error (PE), or
reception in progress flag (RPF) bits
16.5.2.4 Idle Characters
An idle character contains all logic 1s and has no start, stop, or parity bit.
Idle character length depends on the M bit in SCC1. The preamble is a
synchronizing idle character that begins every transmission.
If the TE bit is cleared during a transmission, the TxD pin becomes idle
after completion of the transmission in progress. Clearing and then
setting the TE bit during a transmission queues an idle character to be
sent after the character currently being transmitted.
NOTE:
When a break sequence is followed immediately by an idle character,
this SCI design exhibits a condition in which the break character length
is reduced by one half bit time. In this instance, the break sequence will
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Serial Communications Interface (SCI)
consist of a valid start bit, eight or nine data bits (as defined by the M bit
in SCC1) of logic 0 and one half data bit length of logic 0 in the stop bit
position followed immediately by the idle character. To ensure a break
character of the proper length is transmitted, always queue up a byte of
data to be transmitted while the final break sequence is in progress.
NOTE:
When queueing an idle character, return the TE bit to logic 1 before the
stop bit of the current character shifts out to the TxD pin. Setting TE after
the stop bit appears on TxD causes data previously written to the SCDR
to be lost.
A good time to toggle the TE bit for a queued idle character is when the
SCTE bit becomes set and just before writing the next byte to the SCDR.
16.5.2.5 Inversion of Transmitted Output
The transmit inversion bit (TXINV) in SCI control register 1 (SCC1)
reverses the polarity of transmitted data. All transmitted values, including
idle, break, start, and stop bits, are inverted when TXINV is at logic 1.
(See 16.9.1 SCI Control Register 1.)
16.5.2.6 Transmitter Interrupts
The following conditions can generate CPU interrupt requests from the
SCI transmitter:
•
SCI transmitter empty (SCTE) — The SCTE bit in SCS1 indicates
that the SCDR has transferred a character to the transmit shift
register. SCTE can generate a transmitter CPU interrupt request.
Setting the SCI transmit interrupt enable bit, SCTIE, in SCC2
enables the SCTE bit to generate transmitter CPU interrupt
requests.
•
Transmission complete (TC) — The TC bit in SCS1 indicates that
the transmit shift register and the SCDR are empty and that no
break or idle character has been generated. The transmission
complete interrupt enable bit, TCIE, in SCC2 enables the TC bit to
generate transmitter CPU interrupt requests.
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Serial Communications Interface (SCI)
16.5.3 Receiver
Figure 16-6 shows the structure of the SCI receiver.
INTERNAL BUS
SCR1
SCP0
SCR0
BAUD
DIVIDER
÷ 16
CGMXCLK
DATA
RECOVERY
RxD
BKF
ALL ZEROS
CPU INTERRUPT REQUEST
ERROR CPU INTERRUPT REQUEST
RPF
11-BIT
RECEIVE SHIFT REGISTER
STOP
PRESCALER
H
ALL ONES
÷4
SCI DATA REGISTER
8
7
6
M
WAKE
ILTY
PEN
PTY
START
SCR2
5
4
3
2
1
0
L
MSB
SCP1
SCRF
WAKEUP
LOGIC
PARITY
CHECKING
IDLE
ILIE
SCRF
SCRIE
OR
ORIE
NF
NEIE
FE
FEIE
PE
PEIE
RWU
IDLE
R8
ILIE
SCRIE
OR
ORIE
NF
NEIE
FE
FEIE
PE
PEIE
Figure 16-6. SCI Receiver Block Diagram
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Register Name
Bit 7
6
5
4
3
2
1
Bit 0
LOOPS
ENSCI
TXINV
M
WAKE
ILTY
PEN
PTY
0
0
0
0
0
0
0
0
SCTIE
TCIE
SCRIE
ILIE
TE
RE
RWU
SBK
Reset:
0
0
0
0
0
0
0
0
Read:
R8
T8
R
R
ORIE
NEIE
FEIE
PEIE
SCI Control Register 1 (SCC1)
Read:
Write:
Reset:
SCI Control Register 2 (SCC2)
Read:
Write:
SCI Control Register 3 (SCC3)
Write:
Reset:
U
U
0
0
0
0
0
0
Read:
SCTE
TC
SCRF
IDLE
OR
NF
FE
PE
Reset:
1
1
0
0
0
0
0
0
Read:
0
0
0
0
0
0
BKF
RPF
Reset:
0
0
0
0
0
0
0
0
Read:
R7
R6
R5
R4
R3
R2
R1
R0
Write:
T7
T6
T5
T4
T3
T2
T1
T0
SCI Status Register 1 (SCS1)
Write:
SCI Status Register 2 (SCS2)
Write:
SCI Data Register (SCDR)
Reset:
SCI Baud Rate Register (SCBR)
Read:
Unaffected by Reset
0
0
0
0
Write:
Reset:
SCP1
SCP0
R
SCR2
SCR1
SCR0
0
0
0
0
0
0
= Unimplemented
U = Unaffected
R
= Reserved
Figure 16-7. SCI I/O Receiver Register Summary
Table 16-4. SCI Receiver I/O Address Summary
Register
SCC1
SCC2
SCC3
SCS1
SCS2
SCDR
SCBR
Address
$0013
$0014
$0015
$0016
$0017
$0018
$0019
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16.5.3.1 Character Length
The receiver can accommodate either 8-bit or 9-bit data. The state of the
M bit in SCI control register 1 (SCC1) determines character length.
When receiving 9-bit data, bit R8 in SCI control register 2 (SCC2) is the
ninth bit (bit 8). When receiving 8-bit data, bit R8 is a copy of the eighth
bit (bit 7).
16.5.3.2 Character Reception
During an SCI reception, the receive shift register shifts characters in
from the RxD pin. The SCI data register (SCDR) is the read-only buffer
between the internal data bus and the receive shift register.
After a complete character shifts into the receive shift register, the data
portion of the character transfers to the SCDR. The SCI receiver full bit,
SCRF, in SCI status register 1 (SCS1) becomes set, indicating that the
received byte can be read. If the SCI receive interrupt enable bit, SCRIE,
in SCC2 is also set, the SCRF bit generates a receiver CPU interrupt
request.
16.5.3.3 Data Sampling
The receiver samples the RxD pin at the RT clock rate. The RT clock is
an internal signal with a frequency 16 times the baud rate. To adjust for
baud rate mismatch, the RT clock is resynchronized at the following
times (see Figure 16-8):
•
After every start bit
•
After the receiver detects a data bit change from logic 1 to logic 0
(after the majority of data bit samples at RT8, RT9, and RT10
returns a valid logic 1 and the majority of the next RT8, RT9, and
RT10 samples returns a valid logic 0)
To locate the start bit, data recovery logic does an asynchronous search
for a logic 0 preceded by three logic 1s. When the falling edge of a
possible start bit occurs, the RT clock begins to count to 16.
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START BIT
RxD
START BIT
QUALIFICATION
SAMPLES
LSB
START BIT
DATA
VERIFICATION SAMPLING
RT CLOCK
STATE
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT5
RT6
RT7
RT8
RT9
RT10
RT11
RT12
RT13
RT14
RT15
RT16
RT1
RT2
RT3
RT4
RT
CLOCK
RT CLOCK
RESET
Figure 16-8. Receiver Data Sampling
To verify the start bit and to detect noise, data recovery logic takes
samples at RT3, RT5, and RT7. Table 16-5 summarizes the results of
the start bit verification samples.
Table 16-5. Start Bit Verification
RT3, RT5, and RT7 Samples
Start Bit Verification
Noise Flag
000
Yes
0
001
Yes
1
010
Yes
1
011
No
0
100
Yes
1
101
No
0
110
No
0
111
No
0
If start bit verification is not successful, the RT clock is reset and a new
search for a start bit begins.
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To determine the value of a data bit and to detect noise, recovery logic
takes samples at RT8, RT9, and RT10. Table 16-6 summarizes the
results of the data bit samples.
Table 16-6. Data Bit Recovery
NOTE:
RT8, RT9, and RT10 Samples
Data Bit Determination
Noise Flag
000
0
0
001
0
1
010
0
1
011
1
1
100
0
1
101
1
1
110
1
1
111
1
0
The RT8, RT9, and RT10 samples do not affect start bit verification. If
any or all of the RT8, RT9, and RT10 start bit samples are logic 1s
following a successful start bit verification, the noise flag (NF) is set and
the receiver assumes that the bit is a start bit.
To verify a stop bit and to detect noise, recovery logic takes samples at
RT8, RT9, and RT10. Table 16-7 summarizes the results of the stop bit
samples.
Table 16-7. Stop Bit Recovery
RT8, RT9, and RT10 Samples
Framing Error Flag
Noise Flag
000
1
0
001
1
1
010
1
1
011
0
1
100
1
1
101
0
1
110
0
1
111
0
0
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16.5.3.4 Framing Errors
If the data recovery logic does not detect a logic 1 where the stop bit
should be in an incoming character, it sets the framing error bit, FE, in
SCS1. A break character also sets the FE bit because a break character
has no stop bit. The FE bit is set at the same time that the SCRF bit is
set.
16.5.3.5 Baud Rate Tolerance
A transmitting device may be operating at a baud rate below or above
the receiver baud rate. Accumulated bit time misalignment can cause
one of the three stop bit data samples to fall outside the actual stop bit.
Then a noise error occurs. If more than one of the samples is outside the
stop bit, a framing error occurs. In most applications, the baud rate
tolerance is much more than the degree of misalignment that is likely to
occur.
As the receiver samples an incoming character, it resynchronizes the RT
clock on any valid falling edge within the character. Resynchronization
within characters corrects misalignments between transmitter bit times
and receiver bit times.
Slow Data Tolerance
Figure 16-9 shows how much a slow received character can be
misaligned without causing a noise error or a framing error. The slow
stop bit begins at RT8 instead of RT1 but arrives in time for the stop
bit data samples at RT8, RT9, and RT10.
MSB
STOP
RT16
RT15
RT14
RT13
RT12
RT11
RT10
RT9
RT8
RT7
RT6
RT5
RT4
RT3
RT2
RT1
RECEIVER
RT CLOCK
DATA
SAMPLES
Figure 16-9. Slow Data
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Serial Communications Interface (SCI)
For an 8-bit character, data sampling of the stop bit takes the receiver
9 bit times × 16 RT cycles + 10 RT cycles = 154 RT cycles.
With the misaligned character shown in Figure 16-9, the receiver
counts 154 RT cycles at the point when the count of the transmitting
device is 9 bit times × 16 RT cycles + 3 RT cycles = 147 RT cycles.
The maximum percent difference between the receiver count and the
transmitter count of a slow 8-bit character with no errors is
154 – 147 × 100 = 4.54%
-------------------------154
For a 9-bit character, data sampling of the stop bit takes the receiver
10 bit times × 16 RT cycles + 10 RT cycles = 170 RT cycles.
With the misaligned character shown in Figure 16-9, the receiver
counts 170 RT cycles at the point when the count of the transmitting
device is 10 bit times × 16 RT cycles + 3 RT cycles = 163 RT cycles.
The maximum percent difference between the receiver count and the
transmitter count of a slow 9-bit character with no errors is
170 – 163 × 100 = 4.12%
-------------------------170
Fast Data Tolerance
Figure 16-10 shows how much a fast received character can be
misaligned without causing a noise error or a framing error. The fast
stop bit ends at RT10 instead of RT16 but is still there for the stop bit
data samples at RT8, RT9, and RT10.
STOP
IDLE OR NEXT CHARACTER
RT16
RT15
RT14
RT13
RT12
RT11
RT10
RT9
RT8
RT7
RT6
RT5
RT4
RT3
RT2
RT1
RECEIVER
RT CLOCK
DATA
SAMPLES
Figure 16-10. Fast Data
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Serial Communications Interface (SCI)
For an 8-bit character, data sampling of the stop bit takes the receiver
9 bit times × 16 RT cycles + 10 RT cycles = 154 RT cycles.
With the misaligned character shown in Figure 16-10, the receiver
counts 154 RT cycles at the point when the count of the transmitting
device is 10 bit times × 16 RT cycles = 160 RT cycles.
The maximum percent difference between the receiver count and the
transmitter count of a fast 8-bit character with no errors is
154 – 160 × 100 = 3.90%.
-------------------------154
For a 9-bit character, data sampling of the stop bit takes the receiver
10 bit times × 16 RT cycles + 10 RT cycles = 170 RT cycles.
With the misaligned character shown in Figure 16-10, the receiver
counts 170 RT cycles at the point when the count of the transmitting
device is 11 bit times × 16 RT cycles = 176 RT cycles.
The maximum percent difference between the receiver count and the
transmitter count of a fast 9-bit character with no errors is
170 – 176 × 100 = 3.53%.
-------------------------170
16.5.3.6 Receiver Wakeup
So that the MCU can ignore transmissions intended only for other
receivers in multiple-receiver systems, the receiver can be put into a
standby state. Setting the receiver wakeup bit, RWU, in SCC2 puts the
receiver into a standby state during which receiver interrupts are
disabled.
Depending on the state of the WAKE bit in SCC1, either of two
conditions on the RxD pin can bring the receiver out of the standby state:
•
Address mark — An address mark is a logic 1 in the most
significant bit position of a received character. When the WAKE bit
is set, an address mark wakes the receiver from the standby state
by clearing the RWU bit. The address mark also sets the SCI
receiver full bit, SCRF. Software can then compare the character
containing the address mark to the user-defined address of the
receiver. If they are the same, the receiver remains awake and
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Serial Communications Interface (SCI)
processes the characters that follow. If they are not the same,
software can set the RWU bit and put the receiver back into the
standby state.
•
NOTE:
Idle input line condition — When the WAKE bit is clear, an idle
character on the RxD pin wakes the receiver from the standby
state by clearing the RWU bit. The idle character that wakes the
receiver does not set the receiver idle bit, IDLE, or the SCI receiver
full bit, SCRF. The idle line type bit, ILTY, determines whether the
receiver begins counting logic 1s as idle character bits after the
start bit or after the stop bit.
With the WAKE bit clear, setting the RWU bit after the RxD pin has been
idle may cause the receiver to wake up immediately.
16.5.3.7 Receiver Interrupts
The following sources can generate CPU interrupt requests from the SCI
receiver:
•
SCI receiver full (SCRF) — The SCRF bit in SCS1 indicates that
the receive shift register has transferred a character to the SCDR.
SCRF can generate a receiver CPU interrupt request. Setting the
SCI receive interrupt enable bit, SCRIE, in SCC2 enables the
SCRF bit to generate receiver CPU interrupts.
•
Idle input (IDLE) — The IDLE bit in SCS1 indicates that 10 or 11
consecutive logic 1s shifted in from the RxD pin. The idle line
interrupt enable bit, ILIE, in SCC2 enables the IDLE bit to generate
CPU interrupt requests.
16.5.3.8 Error Interrupts
The following receiver error flags in SCS1 can generate CPU interrupt
requests:
•
Receiver overrun (OR) — The OR bit indicates that the receive
shift register shifted in a new character before the previous
character was read from the SCDR. The previous character
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remains in the SCDR, and the new character is lost. The overrun
interrupt enable bit, ORIE, in SCC3 enables OR to generate SCI
error CPU interrupt requests.
•
Noise flag (NF) — The NF bit is set when the SCI detects noise on
incoming data or break characters, including start, data, and stop
bits. The noise error interrupt enable bit, NEIE, in SCC3 enables
NF to generate SCI error CPU interrupt requests.
•
Framing error (FE) — The FE bit in SCS1 is set when a logic 0
occurs where the receiver expects a stop bit. The framing error
interrupt enable bit, FEIE, in SCC3 enables FE to generate SCI
error CPU interrupt requests.
•
Parity error (PE) — The PE bit in SCS1 is set when the SCI
detects a parity error in incoming data. The parity error interrupt
enable bit, PEIE, in SCC3 enables PE to generate SCI error CPU
interrupt requests.
16.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low powerconsumption standby modes.
16.6.1 Wait Mode
The SCI module remains active in wait mode. Any enabled CPU
interrupt request from the SCI module can bring the MCU out of wait
mode.
If SCI module functions are not required during wait mode, reduce power
consumption by disabling the module before executing the WAIT
instruction.
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Serial Communications Interface (SCI)
16.6.2 Stop Mode
The SCI module is inactive in stop mode. The STOP instruction does not
affect SCI register states. Any enabled CPU interrupt request from the
SCI module does not bring the MCU out of Stop mode. SCI module
operation resumes after the MCU exits stop mode.
Because the internal clock is inactive during stop mode, entering stop
mode during an SCI transmission or reception results in invalid data.
16.7 SCI During Break Module Interrupts
The BCFE bit in the break flag control register (BFCR) enables software
to clear status bits during the break state. (See Break Module on page
171).
To allow software to clear status bits during a break interrupt, write a
logic 1 to the BCFE bit. If a status bit is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect status bits during the break state, write a logic 0 to the BCFE
bit. With BCFE at logic 0 (its default state), software can read and write
I/O registers during the break state without affecting status bits. Some
status bits have a two-step read/write clearing procedure. If software
does the first step on such a bit before the break, the bit cannot change
during the break state as long as BCFE is at logic 0. After the break,
doing the second step clears the status bit.
16.8 I/O Signals
Port E shares two of its pins with the SCI module. The two SCI I/O pins
are:
•
PTE0/TxD — Transmit data
•
PTE1/RxD — Receive data
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Serial Communications Interface (SCI)
16.8.1 PTE0/TxD (Transmit Data)
The PTE0/TxD pin is the serial data output from the SCI transmitter. The
SCI shares the PTE0/TxD pin with port E. When the SCI is enabled, the
PTE0/TxD pin is an output regardless of the state of the DDRE2 bit in
data direction register E (DDRE).
16.8.2 PTE1/RxD (Receive Data)
The PTE1/RxD pin is the serial data input to the SCI receiver. The SCI
shares the PTE1/RxD pin with port E. When the SCI is enabled, the
PTE1/RxD pin is an input regardless of the state of the DDRE1 bit in data
direction register E (DDRE).
16.9 I/O Registers
The following I/O registers control and monitor SCI operation:
•
SCI control register 1 (SCC1)
•
SCI control register 2 (SCC2)
•
SCI control register 3 (SCC3)
•
SCI status register 1 (SCS1)
•
SCI status register 2 (SCS2)
•
SCI data register (SCDR)
•
SCI baud rate register (SCBR)
16.9.1 SCI Control Register 1
SCI control register 1:
•
Enables loop mode operation
•
Enables the SCI
•
Controls output polarity
•
Controls character length
•
Controls SCI wakeup method
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Serial Communications Interface (SCI)
•
Controls idle character detection
•
Enables parity function
•
Controls parity type
Address:
Read:
Write:
Reset:
$0013
Bit 7
6
5
4
3
2
1
Bit 0
LOOPS
ENSCI
TXINV
M
WAKE
ILLTY
PEN
PTY
0
0
0
0
0
0
0
0
Figure 16-11. SCI Control Register 1 (SCC1)
LOOPS — Loop Mode Select Bit
This read/write bit enables loop mode operation. In loop mode the
RxD pin is disconnected from the SCI, and the transmitter output goes
into the receiver input. Both the transmitter and the receiver must be
enabled to use loop mode. Reset clears the LOOPS bit.
1 = Loop mode enabled
0 = Normal operation enabled
ENSCI — Enable SCI Bit
This read/write bit enables the SCI and the SCI baud rate generator.
Clearing ENSCI sets the SCTE and TC bits in SCI status register 1
and disables transmitter interrupts. Reset clears the ENSCI bit.
1 = SCI enabled
0 = SCI disabled
TXINV — Transmit Inversion Bit
This read/write bit reverses the polarity of transmitted data. Reset
clears the TXINV bit.
1 = Transmitter output inverted
0 = Transmitter output not inverted
NOTE:
Setting the TXINV bit inverts all transmitted values, including idle, break,
start, and stop bits.
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Serial Communications Interface (SCI)
M — Mode (Character Length) Bit
This read/write bit determines whether SCI characters are eight or
nine bits long. (See Table 16-8).The ninth bit can serve as an extra
stop bit, as a receiver wakeup signal, or as a parity bit. Reset clears
the M bit.
1 = 9-bit SCI characters
0 = 8-bit SCI characters
WAKE — Wakeup Condition Bit
This read/write bit determines which condition wakes up the SCI: a
logic 1 (address mark) in the most significant bit position of a received
character or an idle condition on the RxD pin. Reset clears the WAKE
bit.
1 = Address mark wakeup
0 = Idle line wakeup
ILTY — Idle Line Type Bit
This read/write bit determines when the SCI starts counting logic 1s
as idle character bits. The counting begins either after the start bit or
after the stop bit. If the count begins after the start bit, then a string of
logic 1s preceding the stop bit may cause false recognition of an idle
character. Beginning the count after the stop bit avoids false idle
character recognition, but requires properly synchronized
transmissions. Reset clears the ILTY bit.
1 = Idle character bit count begins after stop bit
0 = Idle character bit count begins after start bit
PEN — Parity Enable Bit
This read/write bit enables the SCI parity function. (See Table 16-8).
When enabled, the parity function inserts a parity bit in the most
significant bit position. (See Table 16-7). Reset clears the PEN bit.
1 = Parity function enabled
0 = Parity function disabled
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Serial Communications Interface (SCI)
PTY — Parity Bit
This read/write bit determines whether the SCI generates and checks
for odd parity or even parity. (See Table 16-8). Reset clears the PTY
bit.
1 = Odd parity
0 = Even parity
NOTE:
Changing the PTY bit in the middle of a transmission or reception can
generate a parity error.
Table 16-8. Character Format Selection
Control Bits
Character Format
M
PEN:PTY
Start
Bits
Data
Bits
Parity
Stop
Bits
Character
Length
0
0X
1
8
None
1
10 Bits
1
0X
1
9
None
1
11 Bits
0
10
1
7
Even
1
10 Bits
0
11
1
7
Odd
1
10 Bits
1
10
1
8
Even
1
11 Bits
1
11
1
8
Odd
1
11 Bits
16.9.2 SCI Control Register 2
SCI control register 2:
•
Enables the following CPU interrupt requests:
– Enables the SCTE bit to generate transmitter CPU interrupt
requests
– Enables the TC bit to generate transmitter CPU interrupt
requests
– Enables the SCRF bit to generate receiver CPU interrupt
requests
– Enables the IDLE bit to generate receiver CPU interrupt
requests
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•
Enables the transmitter
•
Enables the receiver
•
Enables SCI wakeup
•
Transmits SCI break characters
Address:
Read:
Write:
Reset:
$0014
Bit 7
6
5
4
3
2
1
Bit 0
SCTIE
TCIE
SCRIE
ILIE
TE
RE
RWU
SBK
0
0
0
0
0
0
0
0
Figure 16-12. SCI Control Register 2 (SCC2)
SCTIE — SCI Transmit Interrupt Enable Bit
This read/write bit enables the SCTE bit to generate SCI transmitter
CPU interrupt requests. Setting the SCTIE bit in SCC3 enables the
SCTE bit to generate CPU interrupt requests. Reset clears the SCTIE
bit.
1 = SCTE enabled to generate CPU interrupt
0 = SCTE not enabled to generate CPU interrupt
TCIE — Transmission Complete Interrupt Enable Bit
This read/write bit enables the TC bit to generate SCI transmitter CPU
interrupt requests. Reset clears the TCIE bit.
1 = TC enabled to generate CPU interrupt requests
0 = TC not enabled to generate CPU interrupt requests
SCRIE — SCI Receive Interrupt Enable Bit
This read/write bit enables the SCRF bit to generate SCI receiver
CPU interrupt requests. Setting the SCRIE bit in SCC3 enables the
SCRF bit to generate CPU interrupt requests. Reset clears the SCRIE
bit.
1 = SCRF enabled to generate CPU interrupt
0 = SCRF not enabled to generate CPU interrupt
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Serial Communications Interface (SCI)
ILIE — Idle Line Interrupt Enable Bit
This read/write bit enables the IDLE bit to generate SCI receiver CPU
interrupt requests. Reset clears the ILIE bit.
1 = IDLE enabled to generate CPU interrupt requests
0 = IDLE not enabled to generate CPU interrupt requests
TE — Transmitter Enable Bit
Setting this read/write bit begins the transmission by sending a
preamble of 10 or 11 logic 1s from the transmit shift register to the
TxD pin. If software clears the TE bit, the transmitter completes any
transmission in progress before the TxD returns to the idle condition
(logic 1). Clearing and then setting TE during a transmission queues
an idle character to be sent after the character currently being
transmitted. Reset clears the TE bit.
1 = Transmitter enabled
0 = Transmitter disabled
NOTE:
Writing to the TE bit is not allowed when the enable SCI bit (ENSCI) is
clear. ENSCI is in SCI control register 1.
RE — Receiver Enable Bit
Setting this read/write bit enables the receiver. Clearing the RE bit
disables the receiver but does not affect receiver interrupt flag bits.
Reset clears the RE bit.
1 = Receiver enabled
0 = Receiver disabled
NOTE:
Writing to the RE bit is not allowed when the enable SCI bit (ENSCI) is
clear. ENSCI is in SCI control register 1.
RWU — Receiver Wakeup Bit
This read/write bit puts the receiver in a standby state during which
receiver interrupts are disabled. The WAKE bit in SCC1 determines
whether an idle input or an address mark brings the receiver out of the
standby state and clears the RWU bit. Reset clears the RWU bit.
1 = Standby state
0 = Normal operation
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Serial Communications Interface (SCI)
SBK — Send Break Bit
Setting and then clearing this read/write bit transmits a break
character followed by a logic 1. The logic 1 after the break character
guarantees recognition of a valid start bit. If SBK remains set, the
transmitter continuously transmits break characters with no logic 1s
between them. Reset clears the SBK bit.
1 = Transmit break characters
0 = No break characters being transmitted
NOTE:
Do not toggle the SBK bit immediately after setting the SCTE bit.
Toggling SBK before the preamble begins causes the SCI to send a
break character instead of a preamble.
16.9.3 SCI Control Register 3
SCI control register 3:
•
Stores the ninth SCI data bit received and the ninth SCI data bit to
be transmitted.
•
Enables the following interrupts:
– Receiver overrun interrupts
– Noise error interrupts
– Framing error interrupts
– Parity error interrupts
Address:
$0015
Bit 7
Read:
R8
Write:
Reset:
U
6
5
4
3
2
1
Bit 0
T8
R
R
ORIE
NEIE
FEIE
PEIE
U
0
0
0
0
0
0
= Unimplemented
R
= Reserved
U = Unaffected
Figure 16-13. SCI Control Register 3 (SCC3)
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Serial Communications Interface (SCI)
R8 — Received Bit 8
When the SCI is receiving 9-bit characters, R8 is the read-only ninth
bit (bit 8) of the received character. R8 is received at the same time
that the SCDR receives the other 8 bits.
When the SCI is receiving 8-bit characters, R8 is a copy of the eighth
bit (bit 7). Reset has no effect on the R8 bit.
T8 — Transmitted Bit 8
When the SCI is transmitting 9-bit characters, T8 is the read/write
ninth bit (bit 8) of the transmitted character. T8 is loaded into the
transmit shift register at the same time that the SCDR is loaded into
the transmit shift register. Reset has no effect on the T8 bit.
ORIE — Receiver Overrun Interrupt Enable Bit
This read/write bit enables SCI error CPU interrupt requests
generated by the receiver overrun bit, OR.
1 = SCI error CPU interrupt requests from OR bit enabled
0 = SCI error CPU interrupt requests from OR bit disabled
NEIE — Receiver Noise Error Interrupt Enable Bit
This read/write bit enables SCI error CPU interrupt requests
generated by the noise error bit, NE. Reset clears NEIE.
1 = SCI error CPU interrupt requests from NE bit enabled
0 = SCI error CPU interrupt requests from NE bit disabled
FEIE — Receiver Framing Error Interrupt Enable Bit
This read/write bit enables SCI error CPU interrupt requests
generated by the framing error bit, FE. Reset clears FEIE.
1 = SCI error CPU interrupt requests from FE bit enabled
0 = SCI error CPU interrupt requests from FE bit disabled
PEIE — Receiver Parity Error Interrupt Enable Bit
This read/write bit enables SCI receiver CPU interrupt requests
generated by the parity error bit, PE. Reset clears PEIE.
1 = SCI error CPU interrupt requests from PE bit enabled
0 = SCI error CPU interrupt requests from PE bit disabled
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16.9.4 SCI Status Register 1
SCI status register 1 contains flags to signal the following conditions:
•
Transfer of SCDR data to transmit shift register complete
•
Transmission complete
•
Transfer of receive shift register data to SCDR complete
•
Receiver input idle
•
Receiver overrun
•
Noisy data
•
Framing error
•
Parity error
Address:
Read:
$0016
Bit 7
6
5
4
3
2
1
Bit 0
SCTE
TC
SCRF
IDLE
OR
NF
FE
PE
1
1
0
0
0
0
0
0
Write:
Reset:
= Unimplemented
Figure 16-14. SCI Status Register 1 (SCS1)
SCTE — SCI Transmitter Empty Bit
This clearable, read-only bit is set when the SCDR transfers a
character to the transmit shift register. SCTE can generate an SCI
transmitter CPU interrupt request. When the SCTIE bit in SCC2 is set,
SCTE generates an SCI transmitter CPU interrupt request. In normal
operation, clear the SCTE bit by reading SCS1 with SCTE set and
then writing to SCDR. Reset sets the SCTE bit.
1 = SCDR data transferred to transmit shift register
0 = SCDR data not transferred to transmit shift register
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Serial Communications Interface (SCI)
TC — Transmission Complete Bit
This read-only bit is set when the SCTE bit is set, and no data,
preamble, or break character is being transmitted. TC generates an
SCI transmitter CPU interrupt request if the TCIE bit in SCC2 is also
set. TC is cleared automatically when data, preamble, or break is
queued and ready to be sent. There may be up to 1.5 transmitter
clocks of latency between queueing data, preamble, and break and
the transmission actually starting. Reset sets the TC bit.
1 = No transmission in progress
0 = Transmission in progress
SCRF — SCI Receiver Full Bit
This clearable, read-only bit is set when the data in the receive shift
register transfers to the SCI data register. SCRF can generate an SCI
receiver CPU interrupt request. When the SCRIE bit in SCC2 is set
the SCRF generates a CPU interrupt request. In normal operation,
clear the SCRF bit by reading SCS1 with SCRF set and then reading
the SCDR. Reset clears SCRF.
1 = Received data available in SCDR
0 = Data not available in SCDR
IDLE — Receiver Idle Bit
This clearable, read-only bit is set when 10 or 11 consecutive logic 1s
appear on the receiver input. IDLE generates an SCI error CPU
interrupt request if the ILIE bit in SCC2 is also set. Clear the IDLE bit
by reading SCS1 with IDLE set and then reading the SCDR. After the
receiver is enabled, it must receive a valid character that sets the
SCRF bit before an idle condition can set the IDLE bit. Also, after the
IDLE bit has been cleared, a valid character must again set the SCRF
bit before an idle condition can set the IDLE bit. Reset clears the IDLE
bit.
1 = Receiver input idle
0 = Receiver input active (or idle since the IDLE bit was cleared)
OR — Receiver Overrun Bit
This clearable, read-only bit is set when software fails to read the
SCDR before the receive shift register receives the next character.
The OR bit generates an SCI error CPU interrupt request if the ORIE
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bit in SCC3 is also set. The data in the shift register is lost, but the data
already in the SCDR is not affected. Clear the OR bit by reading SCS1
with OR set and then reading the SCDR. Reset clears the OR bit.
1 = Receive shift register full and SCRF = 1
0 = No receiver overrun
Software latency may allow an overrun to occur between reads of SCS1
and SCDR in the flag-clearing sequence. Figure 16-15 shows the
normal flag-clearing sequence and an example of an overrun caused by
a delayed flag-clearing sequence. The delayed read of SCDR does not
clear the OR bit because OR was not set when SCS1 was read. Byte 2
caused the overrun and is lost. The next flag-clearing sequence reads
byte 3 in the SCDR instead of byte 2.
In applications that are subject to software latency or in which it is
important to know which byte is lost due to an overrun, the flag-clearing
routine can check the OR bit in a second read of SCS1 after reading the
data register.
BYTE 1
BYTE 2
BYTE 3
SCRF = 0
SCRF = 1
SCRF = 0
SCRF = 1
SCRF = 0
SCRF = 1
NORMAL FLAG CLEARING SEQUENCE
BYTE 4
READ SCS1
SCRF = 1
OR = 0
READ SCS1
SCRF = 1
OR = 0
READ SCS1
SCRF = 1
OR = 0
READ SCDR
BYTE 1
READ SCDR
BYTE 2
READ SCDR
BYTE 3
BYTE 1
BYTE 2
BYTE 3
SCRF = 0
OR = 0
SCRF = 1
OR = 1
SCRF = 0
OR = 1
SCRF = 1
SCRF = 1
OR = 1
DELAYED FLAG CLEARING SEQUENCE
BYTE 4
READ SCS1
SCRF = 1
OR = 0
READ SCS1
SCRF = 1
OR = 1
READ SCDR
BYTE 1
READ SCDR
BYTE 3
Figure 16-15. Flag Clearing Sequence
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Serial Communications Interface (SCI)
NF — Receiver Noise Flag Bit
This clearable, read-only bit is set when the SCI detects noise on the
RxD pin. NF generates an NF CPU interrupt request if the NEIE bit in
SCC3 is also set. Clear the NF bit by reading SCS1 and then reading
the SCDR. Reset clears the NF bit.
1 = Noise detected
0 = No noise detected
FE — Receiver Framing Error Bit
This clearable, read-only bit is set when a logic 0 is accepted as the
stop bit. FE generates an SCI error CPU interrupt request if the FEIE
bit in SCC3 also is set. Clear the FE bit by reading SCS1 with FE set
and then reading the SCDR. Reset clears the FE bit.
1 = Framing error detected
0 = No framing error detected
PE — Receiver Parity Error Bit
This clearable, read-only bit is set when the SCI detects a parity error
in incoming data. PE generates a PE CPU interrupt request if the
PEIE bit in SCC3 is also set. Clear the PE bit by reading SCS1 with
PE set and then reading the SCDR. Reset clears the PE bit.
1 = Parity error detected
0 = No parity error detected
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16.9.5 SCI Status Register 2
SCI status register 2 contains flags to signal the following conditions:
•
Break character detected
•
Incoming data
Address:
Read:
$0017
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
BKF
RPF
0
0
0
0
0
0
0
0
Write:
Reset:
= Unimplemented
Figure 16-16. SCI Status Register 2 (SCS2)
BKF — Break Flag Bit
This clearable, read-only bit is set when the SCI detects a break
character on the RxD pin. In SCS1, the FE and SCRF bits are also
set. In 9-bit character transmissions, the R8 bit in SCC3 is cleared.
BKF does not generate a CPU interrupt request. Clear BKF by
reading SCS2 with BKF set and then reading the SCDR. Once
cleared, BKF can become set again only after logic 1s again appear
on the RxD pin followed by another break character. Reset clears the
BKF bit.
1 = Break character detected
0 = No break character detected
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Serial Communications Interface (SCI)
RPF — Reception in Progress Flag Bit
This read-only bit is set when the receiver detects a logic 0 during the
RT1 time period of the start bit search. RPF does not generate an
interrupt request. RPF is reset after the receiver detects false start bits
(usually from noise or a baud rate mismatch), or when the receiver
detects an idle character. Polling RPF before disabling the SCI
module or entering stop mode can show whether a reception is in
progress.
1 = Reception in progress
0 = No reception in progress
16.9.6 SCI Data Register
The SCI data register is the buffer between the internal data bus and the
receive and transmit shift registers. Reset has no effect on data in the
SCI data register.
Address:
$0018
Bit 7
6
5
4
3
2
1
Bit 0
Read:
R7
R6
R5
R4
R3
R2
R1
R0
Write:
T7
T6
T5
T4
T3
T2
T1
T0
Reset:
Unaffected by Reset
Figure 16-17. SCI Data Register (SCDR)
R7/T7:R0/T0 — Receive/Transmit Data Bits
Reading address $0018 accesses the read-only received data bits,
R7:R0. Writing to address $0018 writes the data to be transmitted,
T7:T0. Reset has no effect on the SCI data register.
NOTE:
Do not use read-modify-write instructions on the SCI data register.
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16.9.7 SCI Baud Rate Register
The baud rate register selects the baud rate for both the receiver and the
transmitter.
Address:
Read:
$0019
Bit 7
6
5
4
3
2
1
Bit 0
0
0
SCP1
SCP0
R
SCR2
SCR1
SCR0
0
0
0
0
0
0
0
0
= Unimplemented
R
Write:
Reset:
= Reserved
Figure 16-18. SCI Baud Rate Register (SCBR)
SCP1 and SCP0 — SCI Baud Rate Prescaler Bits
These read/write bits select the baud rate prescaler divisor as shown
in Table 16-9. Reset clears SCP1 and SCP0.
Table 16-9. SCI Baud Rate Prescaling
SCP[1:0]
Prescaler Divisor (PD)
00
1
01
3
10
4
11
13
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Serial Communications Interface (SCI)
SCR2 – SCR0 — SCI Baud Rate Select Bits
These read/write bits select the SCI baud rate divisor as shown in
Table 16-10. Reset clears SCR2–SCR0.
Table 16-10. SCI Baud Rate Selection
SCR[2:1:0]
Baud Rate Divisor (BD)
000
1
001
2
010
4
011
8
100
16
101
32
110
64
111
128
Use the following formula to calculate the SCI baud rate:
f Crystal
Baud rate = -----------------------------------64 × PD × BD
where:
fCrystal = crystal frequency
PD = prescaler divisor
BD = baud rate divisor
Table 16-11 shows the SCI baud rates that can be generated with a
4.9152-MHz crystal.
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Table 16-11. SCI Baud Rate Selection Examples
SCP[1:0]
Prescaler
Divisor
(PD)
SCR[2:1:0]
Baud Rate
Divisor
(BD)
Baud Rate
(fCrystal = 4.9152 MHz)
00
1
000
1
76,800
00
1
001
2
38,400
00
1
010
4
19,200
00
1
011
8
9600
00
1
100
16
4800
00
1
101
32
2400
00
1
110
64
1200
00
1
111
128
600
01
3
000
1
25,600
01
3
001
2
12,800
01
3
010
4
6400
01
3
011
8
3200
01
3
100
16
1600
01
3
101
32
800
01
3
110
64
400
01
3
111
128
200
10
4
000
1
19,200
10
4
001
2
9600
10
4
010
4
4800
10
4
011
8
2400
10
4
100
16
1200
10
4
101
32
600
10
4
110
64
300
10
4
111
128
150
11
13
000
1
5908
11
13
001
2
2954
11
13
010
4
1477
11
13
011
8
739
11
13
100
16
369
11
13
101
32
185
11
13
110
64
92
11
13
111
128
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Technical Data — MC68HC08AZ60A
Section 17. Serial Peripheral Interface (SPI)
17.1 Contents
17.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
17.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .250
17.4
Pin Name Conventions and I/O Register Addresses. . . . . 251
17.5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
17.5.1 Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
17.5.2 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
17.6 Transmission Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
17.6.1 Clock Phase and Polarity Controls. . . . . . . . . . . . . . . . . 256
17.6.2 Transmission Format When CPHA = ‘0’. . . . . . . . . . . . . 257
17.6.3 Transmission Format When CPHA = ‘1’. . . . . . . . . . . . . 258
17.6.4 Transmission Initiation Latency . . . . . . . . . . . . . . . . . . . 259
17.6.5 Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .261
17.6.6 Overflow Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
17.6.7 Mode Fault Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
17.7
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
17.8
Queuing Transmission Data . . . . . . . . . . . . . . . . . . . . . . . . 266
17.9
Resetting the SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
17.10 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
17.10.1 WAIT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
17.10.2 STOP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
17.11 SPI During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . 269
17.12 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
17.12.1 MISO (MasterIn/Slave Out) . . . . . . . . . . . . . . . . . . . . . . .271
17.12.2 MOSI (Master Out/Slave In) . . . . . . . . . . . . . . . . . . . . . . . 271
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Serial Peripheral Interface (SPI)
17.12.3 SPSCK (Serial Clock) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
17.12.4 SS (Slave Select) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
17.12.5 VSS (Clock Ground) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
17.13 I/O Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .273
17.13.1 SPI Control Register (SPCR) . . . . . . . . . . . . . . . . . . . . . . 274
17.13.2 SPI Status and Control Register (SPSCR) . . . . . . . . . . . 276
17.13.3 SPI Data Register (SPDR) . . . . . . . . . . . . . . . . . . . . . . . . 280
17.2 Introduction
This section describes the serial peripheral interface module (SPI),
which allows full-duplex, synchronous, serial communications with
peripheral devices.
17.3 Features
Features of the SPI module include the following:
•
Full-duplex operation
•
Master and slave modes
•
Double-buffered operation with separate transmit and receive
registers
•
Four master mode frequencies (maximum = bus frequency ÷ 2)
•
Maximum slave mode frequency = bus frequency
•
Serial clock with programmable polarity and phase
•
Two separately enabled interrupts with CPU service:
– SPRF (SPI receiver full)
– SPTE (SPI transmitter empty)
•
Mode fault error flag with CPU interrupt capability
•
Overflow error flag with CPU interrupt capability
•
Programmable wired-OR mode
•
I2C (inter-integrated circuit) compatibility
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17.4 Pin Name Conventions and I/O Register Addresses
The generic names of the SPI input/output (I/O) pins are:
•
SS (slave select)
•
SPSCK (SPI serial clock)
•
MOSI (master out slave in)
•
MISO (master in slave out)
The SPI shares four I/O pins with a parallel I/O port. The full name of an
SPI pin reflects the name of the shared port pin. Table 17-1 shows the
full names of the SPI I/O pins. The generic pin names appear in the text
that follows.:
Table 17-1. Pin Name Conventions
MISO
MOSI
SS
SCK
VSS
PTE5/MISO
PTE6/MOSI
PTE4/SS
PTE7/SPSCK
CGND
SPI Generic Pin Names:
Full SPI Pin Names:
SPI
Table 17-2. I/O Register Addresses
Register name
Register address
SPI Control Register (SPICR)
$0010
SPI Status and Control Register (SPISCR)
$0011
SPI Data Register (SPIDR)
$0012
The generic pins names appear in the text that follows.
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17.5 Functional Description
Figure 17-1 summarizes the SPI I/O registers and Figure 17-2 show the
structure of the SPI module.
Register name
R/W
Bit 7
6
SPRIE
R
0
0
5
4
3
2
1
Bit 0
SPE
SPTIE
0
0
Read:
SPI Control Register (SPCR)
SPMSTR CPOL
CPHA SPWOM
Write:
Reset:
SPI Status and Control Register Read: SPRF
ERRIE
(SPSCR) Write:
1
0
1
OVRF
MODF
SPTE
0
MODFEN SPR1 SPR0
Reset:
0
0
0
0
1
0
0
0
Read:
R7
R6
R5
R4
R3
R2
R1
R0
Write:
T7
T6
T5
T4
T3
T2
T1
T0
SPI Data Register (SPDR)
Reset:
Unaffected by reset
R
= Reserved
= Unimplemented
Figure 17-1. SPI I/O Register Summary
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INTERNAL BUS
TRANSMIT DATA REGISTER
SHIFT REGISTER
BUS CLOCK
7
÷2
CLOCK ÷ 8
DIVIDER ÷ 32
6
5
4
3
2
1
MISO
0
MOSI
RECEIVE DATA REGISTER
PIN
CONTROL
LOGIC
÷ 128
SPMSTR
CLOCK
SELECT
SPE
SPR1
SPSCK
M
CLOCK
LOGIC
S
SS
SPR0
SPMSTR
CPHA
MODFEN
TRANSMITTER CPU INTERRUPT REQUEST
CPOL
SPWOM
ERRIE
SPI
CONTROL
SPTIE
SPRIE
RECEIVER/ERROR CPU INTERRUPT REQUEST
SPE
SPRF
SPTE
OVRF
MODF
Figure 17-2. SPI Module Block Diagram
The SPI module allows full-duplex, synchronous, serial communication
between the MCU and peripheral devices, including other MCUs.
Software can poll the SPI status flags or SPI operation can be interruptdriven. All SPI interrupts can be serviced by the CPU.
The following paragraphs describe the operation of the SPI module.
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Serial Peripheral Interface (SPI)
17.5.1 Master Mode
The SPI operates in master mode when the SPI master bit, SPMSTR, is
set.
NOTE:
Configure the SPI modules as master and slave before enabling them.
Enable the master SPI before enabling the slave SPI. Disable the slave
SPI before disabling the master SPI. See SPI Control Register (SPCR)
on page 274.
Only a master SPI module can initiate transmissions. Software begins
the transmission from a master SPI module by writing to the SPI data
register. If the shift register is empty, the byte immediately transfers to
the shift register, setting the SPI transmitter empty bit, SPTE. The byte
begins shifting out on the MOSI pin under the control of the serial clock.
See Figure 17-3.
The SPR1 and SPR0 bits control the baud rate generator and determine
the speed of the shift register. See SPI Status and Control Register
(SPSCR). Through the SPSCK pin, the baud rate generator of the
master also controls the shift register of the slave peripheral.
As the byte shifts out on the MOSI pin of the master, another byte shifts
in from the slave on the master’s MISO pin. The transmission ends when
the receiver full bit, SPRF, becomes set. At the same time that SPRF
becomes set, the byte from the slave transfers to the receive data
register. In normal operation, SPRF signals the end of a transmission.
Software clears SPRF by reading the SPI status and control register with
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Serial Peripheral Interface (SPI)
SPRF set and then reading the SPI data register. Writing to the SPI data
register clears the SPTIE bit.
MASTER MCU
SHIFT REGISTER
SLAVE MCU
MISO
MISO
MOSI
MOSI
SPSCK
BAUD RATE
GENERATOR
SS
SHIFT REGISTER
SPSCK
VDD
SS
Figure 17-3. Full-duplex Master-Slave Connections
17.5.2 Slave Mode
The SPI operates in slave mode when the SPMSTR bit is clear. In slave
mode the SPSCK pin is the input for the serial clock from the master
MCU. Before a data transmission occurs, the SS pin of the slave MCU
must be at logic ‘0’. SS must remain low until the transmission is
complete. See Mode Fault Error.
In a slave SPI module, data enters the shift register under the control of
the serial clock from the master SPI module. After a byte enters the shift
register of a slave SPI, it transfers to the receive data register, and the
SPRF bit is set. To prevent an overflow condition, slave software must
then read the SPI data register before another byte enters the shift
register.
The maximum frequency of the SPSCK for an SPI configured as a slave
is the bus clock speed (which is twice as fast as the fastest master
SPSCK clock that can be generated). The frequency of the SPSCK for
an SPI configured as a slave does not have to correspond to any
particular SPI baud rate. The baud rate only controls the speed of the
SPSCK generated by an SPI configured as a master. Therefore, the
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Serial Peripheral Interface (SPI)
frequency of the SPSCK for an SPI configured as a slave can be any
frequency less than or equal to the bus speed.
When the master SPI starts a transmission, the data in the slave shift
register begins shifting out on the MISO pin. The slave can load its shift
register with a new byte for the next transmission by writing to its transmit
data register. The slave must write to its transmit data register at least
one bus cycle before the master starts the next transmission. Otherwise
the byte already in the slave shift register shifts out on the MISO pin.
Data written to the slave shift register during a a transmission remains in
a buffer until the end of the transmission.
When the clock phase bit (CPHA) is set, the first edge of SPSCK starts
a transmission. When CPHA is clear, the falling edge of SS starts a
transmission. See Transmission Formats on page 256.
If the write to the data register is late, the SPI transmits the data already
in the shift register from the previous transmission.
NOTE:
SPSCK must be in the proper idle state before the slave is enabled to
prevent SPSCK from appearing as a clock edge.
17.6 Transmission Formats
During an SPI transmission, data is simultaneously transmitted (shifted
out serially) and received (shifted in serially). A serial clock line
synchronizes shifting and sampling on the two serial data lines. A slave
select line allows individual selection of a slave SPI device; slave
devices that are not selected do not interfere with SPI bus activities. On
a master SPI device, the slave select line can optionally be used to
indicate a multiple-master bus contention.
17.6.1 Clock Phase and Polarity Controls
Software can select any of four combinations of serial clock (SCK) phase
and polarity using two bits in the SPI control register (SPCR). The clock
polarity is specified by the CPOL control bit, which selects an active high
or low clock and has no significant effect on the transmission format.
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The clock phase (CPHA) control bit selects one of two fundamentally
different transmission formats. The clock phase and polarity should be
identical for the master SPI device and the communicating slave device.
In some cases, the phase and polarity are changed between
transmissions to allow a master device to communicate with peripheral
slaves having different requirements.
NOTE:
Before writing to the CPOL bit or the CPHA bit, the SPI should be
disabled by clearing the SPI enable bit (SPE).
17.6.2 Transmission Format When CPHA = ‘0’
Figure 17-4 shows an SPI transmission in which CPHA is ‘0’. The figure
should not be used as a replacement for data sheet parametric
information.Two waveforms are shown for SCK: one for CPOL = ‘0’ and
another for CPOL = ‘1’. The diagram may be interpreted as a master or
slave timing diagram since the serial clock (SCK), master in/slave out
(MISO), and master out/slave in (MOSI) pins are directly connected
between the master and the slave. The MISO signal is the output from
the slave, and the MOSI signal is the output from the master. The SS line
is the slave select input to the slave. The slave SPI drives its MISO
output only when its slave select input (SS) is at logic ‘0’, so that only the
selected slave drives to the master. The SS pin of the master is not
shown but is assumed to be inactive. The SS pin of the master must be
high or must be reconfigured as general purpose I/O not affecting the
SPI. See Mode Fault Error. When CPHA = ‘0’, the first SPSCK edge is
the MSB capture strobe. Therefore the slave must begin driving its data
before the first SPSCK edge, and a falling edge on the SS pin is used to
start the transmission. The SS pin must be toggled high and then low
again between each byte transmitted.
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Serial Peripheral Interface (SPI)
SCK CYCLE #
(FOR REFERENCE)
1
2
3
4
5
6
7
8
MSB
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
SCK (CPOL =’0’)
SCK (CPOL =1)
MOSI
(FROM MASTER)
MISO
(FROM SLAVE)
MSB
SS (TO SLAVE)
CAPTURE STROBE
Figure 17-4. Transmission Format (CPHA = ‘0’)
17.6.3 Transmission Format When CPHA = ‘1’
Figure 17-5 shows an SPI transmission in which CPHA is ‘1’. The figure
should not be used as a replacement for data sheet parametric
information. Two waveforms are shown for SCK: one for CPOL = ‘0’ and
another for CPOL = ‘1’. The diagram may be interpreted as a master or
slave timing diagram since the serial clock (SCK), master in/slave out
(MISO), and master out/slave in (MOSI) pins are directly connected
between the master and the slave. The MISO signal is the output from
the slave, and the MOSI signal is the output from the master. The SS line
is the slave select input to the slave. The slave SPI drives its MISO
output only when its slave select input (SS) is at logic ‘0’, so that only the
selected slave drives to the master. The SS pin of the master is not
shown but is assumed to be inactive. The SS pin of the master must be
high or must be reconfigured as general-purpose I/O not affecting the
SPI. See Mode Fault Error. When CPHA = ‘1’, the master begins driving
its MOSI pin on the first SPSCK edge. Therefore the slave uses the first
SPSCK edge as a start transmission signal. The SS pin can remain low
between transmissions. This format may be preferable in systems
having only one master and only one slave driving the MISO data line.
Figure 17-5. Transmission Format (CPHA = ‘1’)
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Serial Peripheral Interface (SPI)
SCK CYCLE #
(FOR REFERENCE)
1
2
3
4
5
6
7
8
MOSI
(FROM MASTER)
MSB
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
MISO
(FROM SLAVE)
MSB
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
SCK (CPOL =’0’)
SCK (CPOL =1)
LSB
SS (TO SLAVE)
CAPTURE STROBE
17.6.4 Transmission Initiation Latency
When the SPI is configured as a master (SPMSTR = ‘1’), transmissions
are started by a software write to the SPDR. CPHA has no effect on the
delay to the start of the transmission, but it does affect the initial state of
the SCK signal. When CPHA = ‘0’, the SCK signal remains inactive for
the first half of the first SCK cycle. When CPHA = ‘1’, the first SCK cycle
begins with an edge on the SCK line from its inactive to its active level.
The SPI clock rate (selected by SPR1:SPR0) affects the delay from the
write to SPDR and the start of the SPI transmission. See Figure 17-6.
The internal SPI clock in the master is a free-running derivative of the
internal MCU clock. It is only enabled when both the SPE and SPMSTR
bits are set to conserve power. SCK edges occur halfway through the
low time of the internal MCU clock. Since the SPI clock is free-running,
it is uncertain where the write to the SPDR will occur relative to the
slower SCK. This uncertainty causes the variation in the initiation delay
shown in Figure 17-6. This delay will be no longer than a single SPI bit
time. That is, the maximum delay is two MCU bus cycles for DIV2, eight
MCU bus cycles for DIV8, 32 MCU bus cycles for DIV32, and 128 MCU
bus cycles for DIV128.
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Serial Peripheral Interface (SPI)
WRITE
TO SPDR
INITIATION DELAY
BUS
CLOCK
MOSI
MSB
BIT 5
BIT 6
SCK
(CPHA = ‘1’)
SCK
(CPHA =’0’)
SCK CYCLE
NUMBER
1
2
3
INITIATION DELAY FROM WRITE SPDR TO TRANSFER BEGIN








WRITE
TO SPDR
BUS
CLOCK
EARLIEST LATEST
WRITE
TO SPDR
(SCK = INTERNAL CLOCK ÷ 2;
2 POSSIBLE START POINTS)
BUS
CLOCK
EARLIEST
(SCK = INTERNAL CLOCK ÷ 8;
8 POSSIBLE START POINTS)
LATEST
EARLIEST
(SCK = INTERNAL CLOCK ÷ 32;
32 POSSIBLE START POINTS)
LATEST
(SCK = INTERNAL CLOCK ÷ 128;
128 POSSIBLE START POINTS)
LATEST
WRITE
TO SPDR
BUS
CLOCK
WRITE
TO SPDR
BUS
CLOCK
EARLIEST
Figure 17-6. Transmission Start Delay (Master)
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17.6.5 Error Conditions
The following flags signal SPI error conditions:
•
Overflow (OVRF) — failing to read the SPI data register before the
next byte enters the shift register results in the OVRF bit becoming
set. The new byte does not transfer to the receive data register,
and the unread byte still can be read by accessing the SPI data
register. OVRF is in the SPI status and control register.
•
Mode fault error (MODF) — the MODF bit indicates that the
voltage on the slave select pin (SS) is inconsistent with the mode
of the SPI. MODF is in the SPI status and control register.
17.6.6 Overflow Error
The overflow flag (OVRF) becomes set if the SPI receive data register
still has unread data from a previous transmission when the capture
strobe of bit 1 of the next transmission occurs. See Figure 17-4 and
Figure 17-5. If an overflow occurs, the data being received is not
transferred to the receive data register so that the unread data can still
be read. Therefore, an overflow error always indicates the loss of data.
OVRF generates a receiver/error CPU interrupt request if the error
interrupt enable bit (ERRIE) is also set. MODF and OVRF can generate
a receiver/error CPU interrupt request. See Figure 17-9. It is not
possible to enable only MODF or OVRF to generate a receiver/error
CPU interrupt request. However, leaving MODFEN low prevents MODF
from being set.
If an end-of-block transmission interrupt was meant to pull the MCU out
of wait, having an overflow condition without overflow interrupts enabled
causes the MCU to hang in wait mode. If the OVRF is enabled to
generate an interrupt, it can pull the MCU out of wait mode instead.
If the CPU SPRF interrupt is enabled and the OVRF interrupt is not,
watch for an overflow condition. Figure 17-7 shows how it is possible to
miss an overflow.
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BYTE 1
BYTE 2
BYTE 3
4
1
BYTE 4
6
8
SPRF
OVRF
READ SPSCR
READ SPDR
2
5
3
7
1
BYTE 1 SETS SPRF BIT.
2
CPU READS SPSCR WITH SPRF BIT SET
AND OVRF BIT CLEAR.
CPU READS BYTE 1 IN SPDR,
CLEARING SPRF BIT.
BYTE 2 SETS SPRF BIT.
3
4
5
CPU READS SPSCRW WITH SPRF BIT SET
AND OVRF BIT CLEAR.
6
BYTE 3 SETS OVRF BIT. BYTE 3 IS LOST.
7
CPU READS BYTE 2 IN SPDR, CLEARING SPRF
BUT NOT OVRF BIT.
8
BYTE 4 FAILS TO SET SPRF BIT BECAUSE
OVRF BIT IS SET. BYTE 4 IS LOST.
Figure 17-7. Missed Read of Overflow Condition
The first part of Figure 17-7 shows how to read the SPSCR and SPDR
to clear the SPRF without problems. However, as illustrated by the
second transmission example, the OVRF flag can be set in the interval
between SPSCR and SPDR being read.
In this case, an overflow can easily be missed. Since no more SPRF
interrupts can be generated until this OVRF is serviced, it will not be
obvious that bytes are being lost as more transmissions are completed.
To prevent this, the OVRF interrupt should be enabled, or alternatively
another read of the SPSCR should be carried out following the read of
the SPDR. This ensures that the OVRF was not set before the SPRF
was cleared and that future transmissions will terminate with an SPRF
interrupt. Figure 17-8 illustrates this process. Generally, to avoid this
second SPSCR read, enable the OVRF to the CPU by setting the ERRIE
bit.
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BYTE 1
SPI RECEIVE
COMPLETE
BYTE 2
BYTE 3
5
1
BYTE 4
11
7
SPRF
OVRF
2
READ SPSCR
4
6
3
READ SPDR
8
1
BYTE 1 SETS SPRF BIT.
2
CPU READS SPSCR WITH SPRF BIT SET
AND OVRF BIT CLEAR.
CPU READS BYTE 1 IN SPDR,
CLEARING SPRF BIT.
3
12
9
10
14
13
8
CPU READS BYTE 2 IN SPDR,
CLEARING SPRF BIT.
9
CPU READS SPSCR AGAIN
TO CHECK OVRF BIT.
10 CPU READS BYTE 2 SPDR,
CLEARING OVRF BIT.
4
CPU READS SPSCR AGAIN
TO CHECK OVRF BIT.
5
BYTE 2 SETS SPRF BIT.
12 CPU READS SPSCR.
6
CPU READS SPSCR WITH SPRF BIT SET
AND OVRF BIT CLEAR.
13 CPU READS BYTE 4 IN SPDR,
CLEARING SPRF BIT.
7
BYTE 3 SETS OVRF BIT. BYTE 3 IS LOST.
11 BYTE 4 SETS SPRF BIT.
14 CPU READS SPSCR AGAIN
TO CHECK OVRF BIT.
Figure 17-8. Clearing SPRF When OVRF Interrupt is Not Enabled
17.6.7 Mode Fault Error
For the MODF flag to be set, the mode fault error enable bit (MODFEN)
must be set. Clearing the MODFEN bit does not clear the MODF flag but
does prevent MODF from being set again after MODF is cleared.
MODF generates a receiver/error CPU interrupt request if the error
interrupt enable bit (ERRIE) is also set. The SPRF, MODF, and OVRF
interrupts share the same CPU interrupt vector. MODF and OVRF can
generate a receiver/error CPU interrupt request. See Figure 17-9. It is
not possible to enable only MODF or OVRF to generate a receiver/error
CPU interrupt request. However, leaving MODFEN low prevents MODF
from being set.
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Serial Peripheral Interface (SPI)
In a master SPI with the mode fault enable bit (MODFEN) set, the mode
fault flag (MODF) is set if SS goes to logic ‘0’. A mode fault in a master
SPI causes the following events to occur:
•
If ERRIE = ‘1’, the SPI generates an SPI receiver/error CPU
interrupt request.
•
The SPE bit is cleared.
•
The SPTE bit is set.
•
The SPI state counter is cleared.
•
The data direction register of the shared I/O port regains control of
port drivers.
NOTE:
To prevent bus contention with another master SPI after a mode fault
error, clear all data direction register (DDR) bits associated with the SPI
shared port pins.
NOTE:
Setting the MODF flag (SPSCR) does not clear the SPMSTR bit.
Reading SPMSTR when MODF = 1 will indicate a MODE fault error
occurred in either master mode or slave mode.
When configured as a slave (SPMSTR = ‘0’), the MODF flag is set if SS
goes high during a transmission. When CPHA = ‘0’, a transmission
begins when SS goes low and ends once the incoming SPSCK goes
back to its idle level following the shift of the eighth data bit. When CPHA
= ‘1’, the transmission begins when the SPSCK leaves its idle level and
SS is already low. The transmission continues until the SPSCK returns
to its IDLE level following the shift of the last data bit. See Transmission
Formats.
NOTE:
When CPHA = ‘0’, a MODF occurs if a slave is selected (SS is at logic
‘0’) and later deselected (SS is at logic ‘1’) even if no SPSCK is sent to
that slave. This happens because SS at logic ‘0’ indicates the start of the
transmission (MISO driven out with the value of MSB) for CPHA = ‘0’.
When CPHA = ‘1’, a slave can be selected and then later deselected with
no transmission occurring. Therefore, MODF does not occur since a
transmission was never begun.
In a slave SPI (MSTR = ‘0’), the MODF bit generates an SPI
receiver/error CPU interrupt request if the ERRIE bit is set. The MODF
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bit does not clear the SPE bit or reset the SPI in any way. Software can
abort the SPI transmission by toggling the SPE bit of the slave.
NOTE:
A logic ‘1’ on the SS pin of a slave SPI puts the MISO pin in a high
impedance state. Also, the slave SPI ignores all incoming SPSCK
clocks, even if a transmission has begun.
To clear the MODF flag, read the SPSCR and then write to the SPCR
register. This entire clearing procedure must occur with no MODF
condition existing or else the flag will not be cleared.
17.7 Interrupts
Four SPI status flags can be enabled to generate CPU interrupt
requests:
Table 17-3. SPI Interrupts
Flag
Request
SPTE (Transmitter Empty)
SPI Transmitter CPU Interrupt Request (SPTIE = 1)
SPRF (Receiver Full)
SPI Receiver CPU Interrupt Request (SPRIE = 1)
OVRF (Overflow)
SPI Receiver/Error Interrupt Request (SPRIE = 1, ERRIE = 1)
MODF (Mode Fault)
SPI Receiver/Error Interrupt Request (SPRIE = 1, ERRIE = 1, MODFEN = ‘1’)
The SPI transmitter interrupt enable bit (SPTIE) enables the SPTE flag
to generate transmitter CPU interrupt requests.
The SPI receiver interrupt enable bit (SPRIE) enables the SPRF bit to
generate receiver CPU interrupt requests, provided that the SPI is
enabled (SPE = 1).
The error interrupt enable bit (ERRIE) enables both the MODF and
OVRF flags to generate a receiver/error CPU interrupt request.
The mode fault enable bit (MODFEN) can prevent the MODF flag from
being set so that only the OVRF flag is enabled to generate
receiver/error CPU interrupt requests.
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Serial Peripheral Interface (SPI)
SPTE
SPTIE
SPE
SPI TRANSMITTER
CPU INTERRUPT REQUEST
SPRIE
SPRF
SPI RECEIVER/ERROR
CPU INTERRUPT REQUEST
ERRIE
MODF
OVRF
Figure 17-9. SPI Interrupt Request Generation
Two sources in the SPI status and control register can generate CPU
interrupt requests:
•
SPI receiver full bit (SPRF) — the SPRF bit becomes set every
time a byte transfers from the shift register to the receive data
register. If the SPI receiver interrupt enable bit, SPRIE, is also set,
SPRF can generate an SPI receiver/error CPU interrupt request.
•
SPI transmitter empty (SPTE) — the SPTE bit becomes set every
time a byte transfers from the transmit data register to the shift
register. If the SPI transmit interrupt enable bit, SPTIE, is also set,
SPTE can generate an SPTE CPU interrupt request.
17.8 Queuing Transmission Data
The double-buffered transmit data register allows a data byte to be
queued and transmitted. For an SPI configured as a master, a queued
data byte is transmitted immediately after the previous transmission has
completed. The SPI transmitter empty flag (SPTE) indicates when the
transmit data buffer is ready to accept new data. Write to the SPI data
register only when the SPTE bit is high. Figure 17-10 shows the timing
associated with doing back-to-back transmissions with the SPI (SPSCK
has CPHA: CPOL = 1:0).
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1
WRITE TO SPDR
SPTE
3
8
5
2
10
PSCK (CPHA:CPOL =‘1’:0)
MOSI
MSB BIT BIT BIT BIT BIT BIT LSB MSB BIT BIT BIT BIT BIT BIT LSB MSB BIT BIT BIT
6
6
5
4
3
2
1
6
5
4
3
2
5
4
1
BYTE 1
BYTE 2
4
SPRF
6
READ SPSCR
11
7
READ SPDR
1
CPU WRITES BYTE 1 TO SPDR, CLEARING
SPTE BIT.
2
BYTE 1 TRANSFERS FROM TRANSMIT DATA
REGISTER TO SHIFT REGISTER, SETTING SPTE BIT.
3
CPU WRITES BYTE 2 TO SPDR, QUEUEING
BYTE 2 AND CLEARING SPTE BIT.
4
FIRST INCOMING BYTE TRANSFERS FROM SHIFT
REGISTER TO RECEIVE DATA REGISTER, SETTING
SPRF BIT.
5
BYTE 2 TRANSFERS FROM TRANSMIT DATA
REGISTER TO SHIFT REGISTER, SETTING SPTE BIT.
6
BYTE 3
9
12
7
CPU READS SPDR, CLEARING SPRF BIT.
8
CPU WRITES BYTE 3 TO SPDR, QUEUEING
BYTE 3 AND CLEARING SPTE BIT.
9
SECOND INCOMING BYTE TRANSFERS FROM SHIFT
REGISTER TO RECEIVE DATA REGISTER, SETTING
SPRF BIT.
10 BYTE 3 TRANSFERS FROM TRANSMIT DATA
REGISTER TO SHIFT REGISTER, SETTING SPTE BIT.
11 CPU READS SPSCR WITH SPRF BIT SET.
12 CPU READS SPDR, CLEARING SPRF BIT.
CPU READS SPSCR WITH SPRF BIT SET.
Figure 17-10. SPRF/SPTE CPU Interrupt Timing
For a slave, the transmit data buffer allows back-to-back transmissions
to occur without the slave having to time the write of its data between the
transmissions. Also, if no new data is written to the data buffer, the last
value contained in the shift register will be the next data word
transmitted.
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Serial Peripheral Interface (SPI)
17.9 Resetting the SPI
Any system reset completely resets the SPI. Partial resets occur
whenever the SPI enable bit (SPE) is low. Whenever SPE is low, the
following occurs:
•
The SPTE flag is set
•
Any transmission currently in progress is aborted
•
The shift register is cleared
•
The SPI state counter is cleared, making it ready for a new
complete transmission
•
All the SPI port logic is defaulted back to being general purpose
I/O.
The following items are reset only by a system reset:
•
All control bits in the SPCR register
•
All control bits in the SPSCR register (MODFEN, ERRIE, SPR1,
and SPR0)
•
The status flags SPRF, OVRF, and MODF
By not resetting the control bits when SPE is low, the user can clear SPE
between transmissions without having to set all control bits again when
SPE is set back high for the next transmission.
By not resetting the SPRF, OVRF, and MODF flags, the user can still
service these interrupts after the SPI has been disabled. The user can
disable the SPI by writing ‘0’ to the SPE bit. The SPI can also be disabled
by a mode fault occurring in an SPI that was configured as a master with
the MODFEN bit set.
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17.10 Low-Power Modes
The WAIT and STOP instructions put the MCU in low powerconsumption standby modes.
17.10.1 WAIT Mode
The SPI module remains active after the execution of a WAIT instruction.
In WAIT mode the SPI module registers are not accessible by the CPU.
Any enabled CPU interrupt request from the SPI module can bring the
MCU out of WAIT mode.
If SPI module functions are not required during WAIT mode, power
consumption can be reduced by disabling the SPI module before
executing the WAIT instruction.
To exit WAIT mode when an overflow condition occurs, the OVRF bit
should be enabled to generate CPU interrupt requests by setting the
error interrupt enable bit (ERRIE). See Interrupts.
17.10.2 STOP Mode
The SPI module is inactive after the execution of a STOP instruction.
The STOP instruction does not affect register conditions. SPI operation
resumes after an external interrupt. If STOP mode is exited by reset, any
transfer in progress is aborted, and the SPI is reset.
17.11 SPI During Break Interrupts
The system integration module (SIM) controls whether status bits in
other modules can be cleared during the break state. The BCFE bit in
the SIM break flag control register (SBFCR) enables software to clear
status bits during the break state. See SIM Break Flag Control
Register (SBFCR).
To allow software to clear status bits during a break interrupt, a ‘1’ should
be written to the BCFE bit. If a status bit is cleared during the break state,
it remains cleared when the MCU exits the break state.
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Serial Peripheral Interface (SPI)
To protect status bits during the break state, a ‘0’ should be written to the
BCFE bit. With BCFE at ‘0’ (its default state), software can read and write
I/O registers during the break state without affecting status bits. Some
status bits have a two-step read/write clearing procedure. If software
does the first step on such a bit before the break, the bit cannot change
during the break state as long as BCFE is a ‘0’. After the break, the
second step clears the status bit.
Since the SPTE bit cannot be cleared during a break with the BCFE bit
cleared, a write to the data register in break mode will not initiate a
transmission, nor will this data be transferred into the shift register.
Therefore, a write to the SPDR in break mode with the BCFE bit cleared
has no effect.
17.12 I/O Signals
The SPI module has five I/O pins and shares four of them with a parallel
I/O port.
•
MISO — data received
•
MOSI — data transmitted
•
SPSCK — serial clock
•
SS — slave select
•
VSS — clock ground
The SPI has limited inter-integrated circuit (I2C) capability (requiring
software support) as a master in a single-master environment. To
communicate with I2C peripherals, MOSI becomes an open-drain output
when the SPWOM bit in the SPI control register is set. In I2C
communication, the MOSI and MISO pins are connected to a
bidirectional pin from the I2C peripheral and through a pullup resistor to
VDD.
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17.12.1 MISO (MasterIn/Slave Out)
MISO is one of the two SPI module pins that transmits serial data. In full
duplex operation, the MISO pin of the master SPI module is connected
to the MISO pin of the slave SPI module. The master SPI simultaneously
receives data on its MISO pin and transmits data from its MOSI pin.
Slave output data on the MISO pin is enabled only when the SPI is
configured as a slave. The SPI is configured as a slave when its
SPMSTR bit is logic ‘0’ and its SS pin is at locic ‘0’. To support a multipleslave system, a logic ‘1’ on the SS pin puts the MISO pin in a highimpedance state.
When enabled, the SPI controls data direction of the MISO pin
regardless of the state of the data direction register of the shared I/O
port.
17.12.2 MOSI (Master Out/Slave In)
MOSI is one of the two SPI module pins that transmits serial data. In full
duplex operation, the MOSI pin of the master SPI module is connected
to the MOSI pin of the slave SPI module. The master SPI simultaneously
transmits data from its MOSI pin and receives data on its MISO pin.
When enabled, the SPI controls data direction of the MOSI pin
regardless of the state of the data direction register of the shared I/O
port.
17.12.3 SPSCK (Serial Clock)
The serial clock synchronizes data transmission between master and
slave devices. In a master MCU, the SPSCK pin is the clock output. In a
slave MCU, the SPSCK pin is the clock input. In full duplex operation, the
master and slave MCUs exchange a byte of data in eight serial clock
cycles.
When enabled, the SPI controls data direction of the SPSCK pin
regardless of the state of the data direction register of the shared I/O
port.
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Serial Peripheral Interface (SPI)
17.12.4 SS (Slave Select)
The SS pin has various functions depending on the current state of the
SPI. For an SPI configured as a slave, the SS is used to select a slave.
For CPHA = ‘0’, the SS is used to define the start of a transmission. See
Transmission Formats. Since it is used to indicate the start of a
transmission, the SS must be toggled high and low between each byte
transmitted for the CPHA = ‘0’ format. However, it can remain low
throughout the transmission for the CPHA = ‘1’ format. See Figure 1711.
MISO/MOSI
BYTE 1
BYTE 2
BYTE 3
MASTER SS
SLAVE SS
(CPHA =’0’)
SLAVE SS
(CPHA = ‘1’)
Figure 17-11. CPHA/SS Timing
When an SPI is configured as a slave, the SS pin is always configured
as an input. It cannot be used as a general purpose I/O regardless of the
state of the MODFEN control bit. However, the MODFEN bit can still
prevent the state of the SS from creating a MODF error. See SPI Status
and Control Register (SPSCR).
NOTE:
A logic ‘1’ on the SS pin of a slave SPI puts the MISO pin in a highimpedance state. The slave SPI ignores all incoming SPSCK clocks,
even if transmission has already begun.
When an SPI is configured as a master, the SS input can be used in
conjunction with the MODF flag to prevent multiple masters from driving
MOSI and SPSCK. See Mode Fault Error. For the state of the SS pin to
set the MODF flag, the MODFEN bit in the SPSCK register must be set.
If the MODFEN bit is low for an SPI master, the SS pin can be used as
a general purpose I/O under the control of the data direction register of
the shared I/O port. With MODFEN high, it is an input-only pin to the SPI
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Serial Peripheral Interface (SPI)
regardless of the state of the data direction register of the shared I/O
port.
The CPU can always read the state of the SS pin by configuring the
appropriate pin as an input and reading the data register. See Table 174.
Table 17-4. SPI Configuration
SPE
SPMSTR MODFEN SPI CONFIGURATION
STATE OF SS LOGIC
0
X
X
Not Enabled
General-purpose I/O; SS
ignored by SPI
1
0
X
Slave
Input-only to SPI
1
1
0
Master without MODF
General-purpose I/O; SS
ignored by SPI
1
1
1
Master with MODF
Input-only to SPI
X = don’t care
17.12.5 VSS
(Clock Ground)
VSS is the ground return for the serial clock pin, SPSCK, and the ground
for the port output buffers. To reduce the ground return path loop and
minimize radio frequency (RF) emissions, connect the ground pin of the
slave to the VSS pin.
17.13 I/O Registers
Three registers control and monitor SPI operation:
•
SPI control register (SPCR)
•
SPI status and control register (SPSCR)
•
SPI data register (SPDR)
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Serial Peripheral Interface (SPI)
17.13.1 SPI Control Register (SPCR)
The SPI control register does the following:
SPCR
•
Enables SPI module interrupt requests
•
Selects CPU interrupt requests
•
Configures the SPI module as master or slave
•
Selects serial clock polarity and phase
•
Configures the SPSCK, MOSI, and MISO pins as open-drain
outputs
•
Enables the SPI module
Bit 7
6
5
4
3
2
1
Bit 0
SPRIE
R
SPMSTR
CPOL
CPHA
SPWOM
SPE
SPTIE
0
0
1
0
1
0
0
0
Read:
Write:
Reset:
R
= Reserved
Figure 17-12. SPI Control Register (SPCR)
SPRIE — SPI Receiver Interrupt Enable
This read/write bit enables CPU interrupt requests generated by the
SPRF bit. The SPRF bit is set when a byte transfers from the shift
register to the receive data register. Reset clears the SPRIE bit.
1 = SPRF CPU interrupt requests enabled
0 = SPRF CPU interrupt requests disabled
SPMSTR — SPI Master
This read/write bit selects master mode operation or slave mode
operation. Reset sets the SPMSTR bit.
1 = Master mode
0 = Slave mode
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CPOL — Clock Polarity
This read/write bit determines the logic state of the SPSCK pin
between transmissions. See Figure 17-4 and Figure 17-5. To
transmit data between SPI modules, the SPI modules must have
identical CPOL bits. Reset clears the CPOL bit.
CPHA — Clock Phase
This read/write bit controls the timing relationship between the serial
clock and SPI data. See Figure 17-4 and Figure 17-5. To transmit
data between SPI modules, the SPI modules must have identical
CPHA bits. When CPHA = ‘0’, the SS pin of the slave SPI module
must be set to logic one between bytes. See Figure 17-11. Reset sets
the CPHA bit.
When CPHA =’0’ for a slave, the falling edge of SS indicates the
beginning of the transmission. This causes the SPI to leave its idle
state and begin driving the MISO pin with the MSB of its data. Once
the transmission begins, no new data is allowed into the shift register
from the data register. Therefore, the slave data register must be
loaded with the desired transmit data before the falling edge of SS.
Any data written after the falling edge is stored in the data register and
transferred to the shift register at the current transmission.
When CPHA = ‘1’ for a slave, the first edge of the SPSCK indicates
the beginning of the transmission. The same applies when SS is high
for a slave. The MISO pin is held in a high-impedance state, and the
incoming SPSCK is ignored. In certain cases, it may also cause the
MODF flag to be set. See Mode Fault Error. A logic ‘1’ on the SS pin
does not affect the state of the SPI state machine in any way.
SPWOM — SPI Wired-OR Mode
This read/write bit disables the pull-up devices on pins SPSCK,
MOSI, and MISO so that those pins become open-drain outputs.
1 = Wired-OR SPSCK, MOSI, and MISO pins
0 = Normal push-pull SPSCK, MOSI, and MISO pins
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Serial Peripheral Interface (SPI)
SPE — SPI Enable
This read/write bit enables the SPI module. Clearing SPE causes a
partial reset of the SPI. See Resetting the SPI. Reset clears the SPE
bit.
1 = SPI module enabled
0 = SPI module disabled
SPTIE— SPI Transmit Interrupt Enable
This read/write bit enables CPU interrupt requests generated by the
SPTE bit. SPTE is set when a byte transfers from the transmit data
register to the shift register. Reset clears the SPTIE bit.
1 = SPTE CPU interrupt requests enabled
0 = SPTE CPU interrupt requests disabled
17.13.2 SPI Status and Control Register (SPSCR)
The SPI status and control register contains flags to signal the following
conditions:
•
Receive data register full
•
Failure to clear SPRF bit before next byte is received (overflow
error)
•
Inconsistent logic level on SS pin (mode fault error)
•
Transmit data register empty
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Serial Peripheral Interface (SPI)
The SPI status and control register also contains bits that perform the
following functions:
•
Enable error interrupts
•
Enable mode fault error detection
•
Select master SPI baud rate
Bit 7
SPSCR
Read:
6
SPRF
5
4
3
2
1
Bit 0
OVRF
MODF
SPTE
MODFE
N
SPR1
SPR0
0
0
0
ERRIE
Write:
Reset:
0
R
0
0
0
= Reserved
1
= Unimplemented
Figure 17-13. SPI Status and Control Register (SPSCR)
SPRF — SPI Receiver Full
This clearable, read-only flag is set each time a byte transfers from
the shift register to the receive data register. SPRF generates a CPU
interrupt request if the SPRIE bit in the SPI control register is set also.
During an SPRF CPU interrupt, the CPU clears SPRF by reading the
SPI status and control register with SPRF set and then reading the
SPI data register. Any read of the SPI data register clears the SPRF
bit.
Reset clears the SPRF bit.
1 = Receive data register full
0 = Receive data register not full
ERRIE — Error Interrupt Enable
This read-only bit enables the MODF and OVRF flags to generate
CPU interrupt requests. Reset clears the ERRIE bit.
1 = MODF and OVRF can generate CPU interrupt requests
0 = MODF and OVRF cannot generate CPU interrupt requests
OVRF — Overflow Flag
This clearable, read-only flag is set if software does not read the byte
in the receive data register before the next byte enters the shift
register. In an overflow condition, the byte already in the receive data
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register is unaffected, and the byte that shifted in last is lost. Clear the
OVRF bit by reading the SPI status and control register with OVRF set
and then reading the SPI data register. Reset clears the OVRF flag.
1 = Overflow
0 = No overflow
MODF — Mode Fault
This clearable, ready-only flag is set in a slave SPI if the SS pin goes
high during a transmission. In a master SPI, the MODF flag is set if
the SS pin goes low at any time. Clear the MODF bit by reading the
SPI status and control register with MODF set and then writing to the
SPI data register. Reset clears the MODF bit.
1 = SS pin at inappropriate logic level
0 = SS pin at appropriate logic level
SPTE — SPI Transmitter Empty
This clearable, read-only flag is set each time the transmit data
register transfers a byte into the shift register. SPTE generates an
SPTE CPU interrupt request if the SPTIE bit in the SPI control register
is set also.
NOTE:
The SPI data register should not be written to unless the SPTE bit is
high.
For an idle master or idle slave that has no data loaded into its
transmit buffer, the SPTE will be set again within two bus cycles since
the transmit buffer empties into the shift register. This allows the user
to queue up a 16-bit value to send. For an already active slave, the
load of the shift register cannot occur until the transmission is
completed. This implies that a back-to-back write to the transmit data
register is not possible. The SPTE indicates when the next write can
occur.
Reset sets the SPTE bit.
1 = Transmit data register empty
0 = Transmit data register not empty
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MODFEN — Mode Fault Enable
This read/write bit, when set to ‘1’, allows the MODF flag to be set. If
the MODF flag is set, clearing the MODFEN does not clear the MODF
flag. If the SPI is enabled as a master and the MODFEN bit is low,
then the SS pin is available as a general purpose I/O.
If the MODFEN bit is set, then this pin is not available as a general
purpose I/O. When the SPI is enabled as a slave, the SS pin is not
available as a general purpose I/O regardless of the value of
MODFEN. See SS (Slave Select).
If the MODFEN bit is low, the level of the SS pin does not affect the
operation of an enabled SPI configured as a master. For an enabled
SPI configured as a slave, having MODFEN low only prevents the
MODF flag from being set. It does not affect any other part of SPI
operation. See Mode Fault Error.
SPR1 and SPR0 — SPI Baud Rate Select
In master mode, these read/write bits select one of four baud rates as
shown in Table 17-5. SPR1 and SPR0 have no effect in slave mode.
Reset clears SPR1 and SPR0.
Table 17-5. SPI Master Baud Rate Selection
SPR1:SPR0
Baud rate divisor (BD)
00
2
01
8
10
32
11
128
The following formula is used to calculate the SPI baud rate:
CGMOUT
Baud rate = --------------------------2 × BD
where:
CGMOUT = base clock output of the clock generator module (CGM)
BD = baud rate divisor
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Serial Peripheral Interface (SPI)
17.13.3 SPI Data Register (SPDR)
The SPI data register is the read/write buffer for the receive data register
and the transmit data register. Writing to the SPI data register writes data
into the transmit data register. Reading the SPI data register reads data
from the receive data register. The transmit data and receive data
registers are separate buffers that can contain different values. See
Figure 17-2.
SPDR
Bit 7
6
5
4
3
2
1
Bit 0
Read:
R7
R6
R5
R4
R3
R2
R1
R0
Write:
T7
T6
T5
T4
T3
T2
T1
T0
Reset:
Indeterminate after reset
Figure 17-14. SPI Data Register (SPDR)
R7:R0/T7:T0 — Receive/Transmit Data Bits
NOTE:
Do not use Read-modify-write instructions on the SPI data register since
the buffer read is not the same as the buffer written.
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Technical Data — MC68HC08AZ60A
Section 18. Timer Interface Module B (TIMB)
18.1 Contents
18.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
18.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .282
18.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
18.4.1 TIMB Counter Prescaler. . . . . . . . . . . . . . . . . . . . . . . . . . 284
18.4.2 Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
18.4.3 Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
18.4.3.1
Unbuffered Output Compare. . . . . . . . . . . . . . . . . . . .286
18.4.3.2
Buffered Output Compare . . . . . . . . . . . . . . . . . . . . . . 287
18.4.4 Pulse Width Modulation (PWM) . . . . . . . . . . . . . . . . . . . 288
18.4.4.1
Unbuffered PWM Signal Generation . . . . . . . . . . . . . 289
18.4.4.2
Buffered PWM Signal Generation. . . . . . . . . . . . . . . . 290
18.4.4.3
PWM Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
18.5
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
18.7
TIMB During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . .293
18.8 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
18.8.1 TIMB Clock Pin (PTD4/ATD12/TBCLK) . . . . . . . . . . . . . . 293
18.8.2 TIMB Channel I/O Pins (PTF5/TBCH1–PTF4/TBCH0) . . 294
18.9 I/O Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .294
18.9.1 TIMB Status and Control Register . . . . . . . . . . . . . . . . . 295
18.9.2 TIMB Counter Registers . . . . . . . . . . . . . . . . . . . . . . . . . 297
18.9.3 TIMB Counter Modulo Registers. . . . . . . . . . . . . . . . . . . 298
18.9.4 TIMB Channel Status and Control Registers. . . . . . . . . 299
18.9.5 TIMB Channel Registers . . . . . . . . . . . . . . . . . . . . . . . . . 303
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Timer Interface Module B (TIMB)
18.2 Introduction
This section describes the timer interface module (TIMB). The TIMB is a
2-channel timer that provides a timing reference with input capture,
output compare and pulse width modulation functions. Figure 18-1 is a
block diagram of the TIMB.
For further information regarding timers on M68HC08 family devices,
please consult the HC08 Timer Reference Manual, TIM08RM/AD.
18.3 Features
Features of the TIMB include:
•
Two Input Capture/Output Compare Channels
– Rising-Edge, Falling-Edge or Any-Edge Input Capture Trigger
– Set, Clear or Toggle Output Compare Action
•
Buffered and Unbuffered Pulse Width Modulation (PWM) Signal
Generation
•
Programmable TIMB Clock Input
– 7 Frequency Internal Bus Clock Prescaler Selection
– External TIMB Clock Input (4 MHz Maximum Frequency)
•
Free-Running or Modulo Up-Count Operation
•
Toggle Any Channel Pin on Overflow
•
TIMB Counter Stop and Reset Bits
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Timer Interface Module B (TIMB)
TCLK
PTD4/ATD12/TBCLK
INTERNAL
BUS CLOCK
PRESCALER SELECT
PRESCALER
TSTOP
PS2
TRST
PS1
PS0
16-BIT COUNTER
INTERRUPT
LOGIC
TOF
TOIE
16-BIT COMPARATOR
TMODH:TMODL
ELS0B
CHANNEL 0
ELS0A
TOV0
CH0MAX
16-BIT COMPARATOR
TCH0H:TCH0L
PTF4
LOGIC
CH0F
16-BIT LATCH
MS0A
ELS1B
CHANNEL 1
ELS1A
TOV1
CH1MAX
16-BIT COMPARATOR
TCH1H:TCH1L
INTERRUPT
LOGIC
CH0IE
MS0B
PTF5
LOGIC
CH1F
16-BIT LATCH
PTF5/TBCH1
INTERRUPT
LOGIC
CH1IE
MS1A
PTF4/TBCH0
Figure 18-1. TIMB Block Diagram
Figure 18-2. TIMB I/O Register Summary
Addr.
Register Name
Bit 7
$0040
TIMB Status/Control Register (TBSC)
$0041
TIMB Counter Register High (TBCNTH)
$0042
TIMB Counter Register Low (TBCNTL)
6
5
TOIE
TSTOP
4
3
0
0
TRST
R
2
1
Bit 0
PS2
PS1
PS0
R:
TOF
W:
0
R:
Bit 15
14
13
12
11
10
9
Bit 8
W:
R
R
R
R
R
R
R
R
R:
Bit 7
6
5
4
3
2
1
Bit 0
W:
R
R
R
R
R
R
R
R
$0043
TIMB Counter Modulo Reg. High R:
(TBMODH) W:
Bit 15
14
13
12
11
10
9
Bit 8
$0044
TIMB Counter Modulo Reg. Low R:
(TBMODL) W:
Bit 7
6
5
4
3
2
1
Bit 0
$0045
TIMB Ch. 0 Status/Control Register R:
(TBSC0) W:
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
14
13
12
11
10
9
Bit 8
$0046
TIMB Ch. 0 Register High (TBCH0H)
R:
W:
CH0F
0
Bit 15
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Timer Interface Module B (TIMB)
Figure 18-2. TIMB I/O Register Summary
Addr.
Register Name
R:
$0047
TIMB Ch. 0 Register Low (TBCH0L)
$0048
TIMB Ch. 1 Status/Control Register R:
(TBSC1) W:
$0049
TIMB Ch. 1 Register High (TBCH1H)
$004A
TIMB Ch. 1 Register Low (TBCH1L)
W:
R:
W:
R:
W:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
CH1F
0
CH1IE
0
R
Bit 15
14
13
12
11
10
9
Bit 8
Bit 7
6
5
4
3
2
1
Bit 0
R
= Reserved
18.4 Functional Description
Figure 18-1 shows the TIMB structure. The central component of the
TIMB is the 16-bit TIMB counter that can operate as a free-running
counter or a modulo up-counter. The TIMB counter provides the timing
reference for the input capture and output compare functions. The TIMB
counter modulo registers, TBMODH–TBMODL, control the modulo
value of the TIMB counter. Software can read the TIMB counter value at
any time without affecting the counting sequence.
The two TIMB channels are programmable independently as input
capture or output compare channels.
18.4.1 TIMB Counter Prescaler
The TIMB clock source can be one of the seven prescaler outputs or the
TIMB clock pin, PTD4/ATD12/TBCLK. The prescaler generates seven
clock rates from the internal bus clock. The prescaler select bits, PS[2:0],
in the TIMB status and control register select the TIMB clock source.
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Timer Interface Module B (TIMB)
18.4.2 Input Capture
An input capture function has three basic parts: edge select logic, an
input capture latch and a 16-bit counter. Two 8-bit registers, which make
up the 16-bit input capture register, are used to latch the value of the
free-running counter after the corresponding input capture edge detector
senses a defined transition. The polarity of the active edge is
programmable. The level transition which triggers the counter transfer is
defined by the corresponding input edge bits (ELSxB and ELSxA in
TBSC0 through TBSC1 control registers with x referring to the active
channel number). When an active edge occurs on the pin of an input
capture channel, the TIMB latches the contents of the TIMB counter into
the TIMB channel registers, TBCHxH–TBCHxL. Input captures can
generate TIMB CPU interrupt requests. Software can determine that an
input capture event has occurred by enabling input capture interrupts or
by polling the status flag bit.
The free-running counter contents are transferred to the TIMB channel
register (TBCHxH–TBCHxL, see TIMB Channel Registers on page
303) on each proper signal transition regardless of whether the TIMB
channel flag (CH0F–CH1F in TBSC0–TBSC1 registers) is set or clear.
When the status flag is set, a CPU interrupt is generated if enabled. The
value of the count latched or “captured” is the time of the event. Because
this value is stored in the input capture register 2 bus cycles after the
actual event occurs, user software can respond to this event at a later
time and determine the actual time of the event. However, this must be
done prior to another input capture on the same pin; otherwise, the
previous time value will be lost.
By recording the times for successive edges on an incoming signal,
software can determine the period and/or pulse width of the signal. To
measure a period, two successive edges of the same polarity are
captured. To measure a pulse width, two alternate polarity edges are
captured. Software should track the overflows at the 16-bit module
counter to extend its range.
Another use for the input capture function is to establish a time
reference. In this case, an input capture function is used in conjunction
with an output compare function. For example, to activate an output
signal a specified number of clock cycles after detecting an input event
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Timer Interface Module B (TIMB)
(edge), use the input capture function to record the time at which the
edge occurred. A number corresponding to the desired delay is added to
this captured value and stored to an output compare register (see TIMB
Channel Registers on page 303). Because both input captures and
output compares are referenced to the same 16-bit modulo counter, the
delay can be controlled to the resolution of the counter independent of
software latencies.
Reset does not affect the contents of the input capture channel register
(TBCHxH–TBCHxL).
18.4.3 Output Compare
With the output compare function, the TIMB can generate a periodic
pulse with a programmable polarity, duration and frequency. When the
counter reaches the value in the registers of an output compare channel,
the TIMB can set, clear or toggle the channel pin. Output compares can
generate TIMB CPU interrupt requests.
18.4.3.1 Unbuffered Output Compare
Any output compare channel can generate unbuffered output compare
pulses as described in Output Compare on page 286. The pulses are
unbuffered because changing the output compare value requires writing
the new value over the old value currently in the TIMB channel registers.
An unsynchronized write to the TIMB channel registers to change an
output compare value could cause incorrect operation for up to two
counter overflow periods. For example, writing a new value before the
counter reaches the old value but after the counter reaches the new
value prevents any compare during that counter overflow period. Also,
using a TIMB overflow interrupt routine to write a new, smaller output
compare value may cause the compare to be missed. The TIMB may
pass the new value before it is written.
Use the following methods to synchronize unbuffered changes in the
output compare value on channel x:
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Timer Interface Module B (TIMB)
•
When changing to a smaller value, enable channel x output
compare interrupts and write the new value in the output compare
interrupt routine. The output compare interrupt occurs at the end
of the current output compare pulse. The interrupt routine has until
the end of the counter overflow period to write the new value.
•
When changing to a larger output compare value, enable TIMB
overflow interrupts and write the new value in the TIMB overflow
interrupt routine. The TIMB overflow interrupt occurs at the end of
the current counter overflow period. Writing a larger value in an
output compare interrupt routine (at the end of the current pulse)
could cause two output compares to occur in the same counter
overflow period.
18.4.3.2 Buffered Output Compare
Channels 0 and 1 can be linked to form a buffered output compare
channel whose output appears on the PTF4/TBCH0 pin. The TIMB
channel registers of the linked pair alternately control the output.
Setting the MS0B bit in TIMB channel 0 status and control register
(TBSC0) links channel 0 and channel 1. The output compare value in the
TIMB channel 0 registers initially controls the output on the
PTF4/TBCH0 pin. Writing to the TIMB channel 1 registers enables the
TIMB channel 1 registers to synchronously control the output after the
TIMB overflows. At each subsequent overflow, the TIMB channel
registers (0 or 1) that control the output are the ones written to last.
TBSC0 controls and monitors the buffered output compare function and
TIMB channel 1 status and control register (TBSC1) is unused. While the
MS0B bit is set, the channel 1 pin, PTF5/TBCH1, is available as a
general-purpose I/O pin.
NOTE:
In buffered output compare operation, do not write new output compare
values to the currently active channel registers. User software should
track the currently active channel to prevent writing a new value to the
active channel. Writing to the active channel registers is the same as
generating unbuffered output compares.
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Timer Interface Module B (TIMB)
18.4.4 Pulse Width Modulation (PWM)
By using the toggle-on-overflow feature with an output compare channel,
the TIMB can generate a PWM signal. The value in the TIMB counter
modulo registers determines the period of the PWM signal. The channel
pin toggles when the counter reaches the value in the TIMB counter
modulo registers. The time between overflows is the period of the PWM
signal.
As Figure 18-3 shows, the output compare value in the TIMB channel
registers determines the pulse width of the PWM signal. The time
between overflow and output compare is the pulse width. Program the
TIMB to clear the channel pin on output compare if the state of the PWM
pulse is logic 1. Program the TIMB to set the pin if the state of the PWM
pulse is logic 0.
OVERFLOW
OVERFLOW
OVERFLOW
PERIOD
PULSE
WIDTH
PTEx/TCHx
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
Figure 18-3. PWM Period and Pulse Width
The value in the TIMB counter modulo registers and the selected
prescaler output determines the frequency of the PWM output. The
frequency of an 8-bit PWM signal is variable in 256 increments. Writing
$00FF (255) to the TIMB counter modulo registers produces a PWM
period of 256 times the internal bus clock period if the prescaler select
value is $000 (see TIMB Status and Control Register).
The value in the TIMB channel registers determines the pulse width of
the PWM output. The pulse width of an 8-bit PWM signal is variable in
256 increments. Writing $0080 (128) to the TIMB channel registers
produces a duty cycle of 128/256 or 50%.
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Timer Interface Module B (TIMB)
18.4.4.1 Unbuffered PWM Signal Generation
Any output compare channel can generate unbuffered PWM pulses as
described in Pulse Width Modulation (PWM) on page 288. The pulses
are unbuffered because changing the pulse width requires writing the
new pulse width value over the value currently in the TIMB channel
registers.
An unsynchronized write to the TIMB channel registers to change a
pulse width value could cause incorrect operation for up to two PWM
periods. For example, writing a new value before the counter reaches
the old value but after the counter reaches the new value prevents any
compare during that PWM period. Also, using a TIMB overflow interrupt
routine to write a new, smaller pulse width value may cause the compare
to be missed. The TIMB may pass the new value before it is written to
the TIMB channel registers.
Use the following methods to synchronize unbuffered changes in the
PWM pulse width on channel x:
NOTE:
•
When changing to a shorter pulse width, enable channel x output
compare interrupts and write the new value in the output compare
interrupt routine. The output compare interrupt occurs at the end
of the current pulse. The interrupt routine has until the end of the
PWM period to write the new value.
•
When changing to a longer pulse width, enable TIMB overflow
interrupts and write the new value in the TIMB overflow interrupt
routine. The TIMB overflow interrupt occurs at the end of the
current PWM period. Writing a larger value in an output compare
interrupt routine (at the end of the current pulse) could cause two
output compares to occur in the same PWM period.
In PWM signal generation, do not program the PWM channel to toggle
on output compare. Toggling on output compare prevents reliable 0%
duty cycle generation and removes the ability of the channel to selfcorrect in the event of software error or noise. Toggling on output
compare also can cause incorrect PWM signal generation when
changing the PWM pulse width to a new, much larger value.
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Technical Data
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Timer Interface Module B (TIMB)
18.4.4.2 Buffered PWM Signal Generation
Channels 0 and 1 can be linked to form a buffered PWM channel whose
output appears on the PTF4/TBCH0 pin. The TIMB channel registers of
the linked pair alternately control the pulse width of the output.
Setting the MS0B bit in TIMB channel 0 status and control register
(TBSC0) links channel 0 and channel 1. The TIMB channel 0 registers
initially control the pulse width on the PTF4/TBCH0 pin. Writing to the
TIMB channel 1 registers enables the TIMB channel 1 registers to
synchronously control the pulse width at the beginning of the next PWM
period. At each subsequent overflow, the TIMB channel registers (0 or
1) that control the pulse width are the ones written to last. TBSC0
controls and monitors the buffered PWM function, and TIMB channel 1
status and control register (TBSC1) is unused. While the MS0B bit is set,
the channel 1 pin, PTF5/TBCH1, is available as a general-purpose I/O
pin.
NOTE:
In buffered PWM signal generation, do not write new pulse width values
to the currently active channel registers. User software should track the
currently active channel to prevent writing a new value to the active
channel. Writing to the active channel registers is the same as
generating unbuffered PWM signals.
18.4.4.3 PWM Initialization
To ensure correct operation when generating unbuffered or buffered
PWM signals, use the following initialization procedure:
1. In the TIMB status and control register (TBSC):
a. Stop the TIMB counter by setting the TIMB stop bit, TSTOP.
b. Reset the TIMB counter and prescaler by setting the TIMB
reset bit, TRST.
2. In the TIMB counter modulo registers (TBMODH–TBMODL) write
the value for the required PWM period.
3. In the TIMB channel x registers (TBCHxH–TBCHxL) write the
value for the required pulse width.
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Timer Interface Module B (TIMB)
4. In TIMB channel x status and control register (TBSCx):
a. Write 0:1 (for unbuffered output compare or PWM signals) or
1:0 (for buffered output compare or PWM signals) to the
mode select bits, MSxB–MSxA (see Table 18-2).
b. Write 1 to the toggle-on-overflow bit, TOVx.
c. Write 1:0 (to clear output on compare) or 1:1 (to set output on
compare) to the edge/level select bits, ELSxB–ELSxA. The
output action on compare must force the output to the
complement of the pulse width level (see Table 18-2).
NOTE:
In PWM signal generation, do not program the PWM channel to toggle
on output compare. Toggling on output compare prevents reliable 0%
duty cycle generation and removes the ability of the channel to selfcorrect in the event of software error or noise. Toggling on output
compare can also cause incorrect PWM signal generation when
changing the PWM pulse width to a new, much larger value.
5. In the TIMB status control register (TBSC) clear the TIMB stop bit,
TSTOP.
Setting MS0B links channels 0 and 1 and configures them for buffered
PWM operation. The TIMB channel 0 registers (TBCH0H–TBCH0L)
initially control the buffered PWM output. TIMB status control register 0
(TBSC0) controls and monitors the PWM signal from the linked
channels. MS0B takes priority over MS0A.
Clearing the toggle-on-overflow bit, TOVx, inhibits output toggles on
TIMB overflows. Subsequent output compares try to force the output to
a state it is already in and have no effect. The result is a 0% duty cycle
output.
Setting the channel x maximum duty cycle bit (CHxMAX) and setting the
TOVx bit generates a 100% duty cycle output (see TIMB Channel
Status and Control Registers on page 299).
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Timer Interface Module B (TIMB)
18.5 Interrupts
The following TIMB sources can generate interrupt requests:
•
TIMB overflow flag (TOF) — The TOF bit is set when the TIMB
counter value reaches the value in the TIMB counter modulo
registers. The TIMB overflow interrupt enable bit, TOIE, enables
TIMB overflow CPU interrupt requests. TOF and TOIE are in the
TIMB status and control register.
•
TIMB channel flags (CH1F–CH0F) — The CHxF bit is set when an
input capture or output compare occurs on channel x. Channel x
TIMB CPU interrupt requests are controlled by the channel x
interrupt enable bit, CHxIE.
18.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low powerconsumption standby modes.
18.6.1 Wait Mode
The TIMB remains active after the execution of a WAIT instruction. In
wait mode, the TIMB registers are not accessible by the CPU. Any
enabled CPU interrupt request from the TIMB can bring the MCU out of
wait mode.
If TIMB functions are not required during wait mode, reduce power
consumption by stopping the TIMB before executing the WAIT
instruction.
18.6.2 Stop Mode
The TIMB is inactive after the execution of a STOP instruction. The
STOP instruction does not affect register conditions or the state of the
TIMB counter. TIMB operation resumes when the MCU exits stop mode.
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Timer Interface Module B (TIMB)
18.7 TIMB During Break Interrupts
A break interrupt stops the TIMB counter and inhibits input captures.
The system integration module (SIM) controls whether status bits in
other modules can be cleared during the break state. The BCFE bit in
the SIM break flag control register (SBFCR) enables software to clear
status bits during the break state (see SIM Break Flag Control Register
(SBFCR) on page 137).
To allow software to clear status bits during a break interrupt, write a
logic 1 to the BCFE bit. If a status bit is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect status bits during the break state, write a logic 0 to the BCFE
bit. With BCFE at logic 0 (its default state), software can read and write
I/O registers during the break state without affecting status bits. Some
status bits have a 2-step read/write clearing procedure. If software does
the first step on such a bit before the break, the bit cannot change during
the break state as long as BCFE is at logic 0. After the break, doing the
second step clears the status bit.
18.8 I/O Signals
Port D shares one of its pins with the TIMB. Port F shares two of its pins
with the TIMB. PTD4/ATD12/TBCLK is an external clock input to the
TIMB prescaler. The two TIMB channel I/O pins are PTF4/TBCH0 and
PTF5/TBCH1.
18.8.1 TIMB Clock Pin (PTD4/ATD12/TBCLK)
PTD4/ATD12/TBCLK is an external clock input that can be the clock
source for the TIMB counter instead of the prescaled internal bus clock.
Select the PTD4/ATD12/TBCLK input by writing logic 1s to the three
prescaler select bits, PS[2:0] (see TIMB Status and Control Register).
The minimum TCLK pulse width, TCLKLMIN or TCLKHMIN, is:
1
------------------------------------- + t SU
bus frequency
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Timer Interface Module B (TIMB)
The maximum TCLK frequency is the least: 4 MHz or bus frequency ÷ 2.
PTD4/ATD12/TBCLK is available as a general-purpose I/O pin or ADC
channel when not used as the TIMB clock input. When the
PTD4/ATD12/TBCLK pin is the TIMB clock input, it is an input regardless
of the state of the DDRD4 bit in data direction register D.
18.8.2 TIMB Channel I/O Pins (PTF5/TBCH1–PTF4/TBCH0)
Each channel I/O pin is programmable independently as an input
capture pin or an output compare pin. PTF4/TBCH0 and PTF5/TBCH1
can be configured as buffered output compare or buffered PWM pins.
18.9 I/O Registers
These I/O registers control and monitor TIMB operation:
•
TIMB status and control register (TBSC)
•
TIMB control registers (TBCNTH–TBCNTL)
•
TIMB counter modulo registers (TBMODH–TBMODL)
•
TIMB channel status and control registers (TBSC0 and TBSC1)
•
TIMB channel registers (TBCH0H–TBCH0L, TBCH1H–TBCH1L)
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Timer Interface Module B (TIMB)
18.9.1 TIMB Status and Control Register
The TIMB status and control register:
•
Enables TIMB overflow interrupts
•
Flags TIMB overflows
•
Stops the TIMB counter
•
Resets the TIMB counter
•
Prescales the TIMB counter clock
Address:
$0040
Bit 7
Read:
TOF
Write:
0
Reset:
0
R
6
5
TOIE
TSTOP
0
1
4
3
0
0
TRST
R
0
0
2
1
Bit 0
PS2
PS1
PS0
0
0
0
= Reserved
Figure 18-4. TIMB Status and Control Register (TBSC)
TOF — TIMB Overflow Flag Bit
This read/write flag is set when the TIMB counter reaches the modulo
value programmed in the TIMB counter modulo registers. Clear TOF
by reading the TIMB status and control register when TOF is set and
then writing a logic 0 to TOF. If another TIMB overflow occurs before
the clearing sequence is complete, then writing logic 0 to TOF has no
effect. Therefore, a TOF interrupt request cannot be lost due to
inadvertent clearing of TOF. Reset clears the TOF bit. Writing a logic
1 to TOF has no effect.
1 = TIMB counter has reached modulo value
0 = TIMB counter has not reached modulo value
TOIE — TIMB Overflow Interrupt Enable Bit
This read/write bit enables TIMB overflow interrupts when the TOF bit
becomes set. Reset clears the TOIE bit.
1 = TIMB overflow interrupts enabled
0 = TIMB overflow interrupts disabled
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Technical Data
Timer Interface Module B (TIMB)
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Timer Interface Module B (TIMB)
TSTOP — TIMB Stop Bit
This read/write bit stops the TIMB counter. Counting resumes when
TSTOP is cleared. Reset sets the TSTOP bit, stopping the TIMB
counter until software clears the TSTOP bit.
1 = TIMB counter stopped
0 = TIMB counter active
NOTE:
Do not set the TSTOP bit before entering wait mode if the TIMB is
required to exit wait mode. Also, when the TSTOP bit is set and the timer
is configured for input capture operation, input captures are inhibited
until TSTOP is cleared.
TRST — TIMB Reset Bit
Setting this write-only bit resets the TIMB counter and the TIMB
prescaler. Setting TRST has no effect on any other registers. Counting
resumes from $0000. TRST is cleared automatically after the TIMB
counter is reset and always reads as logic 0. Reset clears the TRST bit.
1 = Prescaler and TIMB counter cleared
0 = No effect
NOTE:
Setting the TSTOP and TRST bits simultaneously stops the TIMB
counter at a value of $0000.
PS[2:0] — Prescaler Select Bits
These read/write bits select either the PTD4/ATD12/TBCLK pin or
one of the seven prescaler outputs as the input to the TIMB counter
as Table 18-1 shows. Reset clears the PS[2:0] bits.
Table 18-1. Prescaler Selection
PS[2:0]
TIMB Clock Source
000
Internal Bus Clock ÷1
001
Internal Bus Clock ÷ 2
010
Internal Bus Clock ÷ 4
011
Internal Bus Clock ÷ 8
100
Internal Bus Clock ÷ 16
101
Internal Bus Clock ÷ 32
110
Internal Bus Clock ÷ 64
111
PTD4/ATD12/TBCLK
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Timer Interface Module B (TIMB)
18.9.2 TIMB Counter Registers
The two read-only TIMB counter registers contain the high and low bytes
of the value in the TIMB counter. Reading the high byte (TBCNTH)
latches the contents of the low byte (TBCNTL) into a buffer. Subsequent
reads of TBCNTH do not affect the latched TBCNTL value until TBCNTL
is read. Reset clears the TIMB counter registers. Setting the TIMB reset
bit (TRST) also clears the TIMB counter registers.
NOTE:
If TBCNTH is read during a break interrupt, be sure to unlatch TBCNTL
by reading TBCNTL before exiting the break interrupt. Otherwise,
TBCNTL retains the value latched during the break.
Register Name and Address TBCNTH — $0041
Bit 7
6
5
4
3
2
1
Bit 0
Read:
BIT 15
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
Write:
R
R
R
R
R
R
R
R
Reset:
0
0
0
0
0
0
0
0
Register Name and Address TBCNTL — $0042
Bit 7
6
5
4
3
2
1
Bit 0
Read:
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Write:
R
R
R
R
R
R
R
R
Reset:
0
0
0
0
0
0
0
0
R
R = Reserved
Figure 18-5. TIMB Counter Registers (TBCNTH and TBCNTL)
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Timer Interface Module B (TIMB)
18.9.3 TIMB Counter Modulo Registers
The read/write TIMB modulo registers contain the modulo value for the
TIMB counter. When the TIMB counter reaches the modulo value, the
overflow flag (TOF) becomes set and the TIMB counter resumes
counting from $0000 at the next timer clock. Writing to the high byte
(TBMODH) inhibits the TOF bit and overflow interrupts until the low byte
(TBMODL) is written. Reset sets the TIMB counter modulo registers.
Register Name and Address TBMODH — $0043
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
BIT 15
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
1
1
1
1
1
1
1
1
Register Name and Address TBMODL — $0044
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
1
1
1
1
1
1
1
1
Figure 18-6. TIMB Counter Modulo Registers (TBMODH and
TBMODL)
NOTE:
Reset the TIMB counter before writing to the TIMB counter modulo
registers.
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Timer Interface Module B (TIMB)
18.9.4 TIMB Channel Status and Control Registers
Each of the TIMB channel status and control registers:
•
Flags input captures and output compares
•
Enables input capture and output compare interrupts
•
Selects input capture, output compare or PWM operation
•
Selects high, low or toggling output on output compare
•
Selects rising edge, falling edge or any edge as the active input
capture trigger
•
Selects output toggling on TIMB overflow
•
Selects 0% and 100% PWM duty cycle
•
Selects buffered or unbuffered output compare/PWM operation
Register Name and Address TBSC0 — $0045
Bit 7
Read:
CH0F
Write:
0
Reset:
0
6
5
4
3
2
1
Bit 0
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
0
0
0
0
0
0
0
4
3
2
1
Bit 0
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
0
0
0
0
0
Register Name and Address TBSC1 — $0048
Bit 7
Read:
CH1F
Write:
0
Reset:
0
R
6
CH1IE
0
5
0
R
0
R = Reserved
Figure 18-7. TIMB Channel Status and Control Registers
(TBSC0–TBSC1)
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Technical Data
Timer Interface Module B (TIMB)
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Timer Interface Module B (TIMB)
CHxF — Channel x Flag Bit
When channel x is an input capture channel, this read/write bit is set
when an active edge occurs on the channel x pin. When channel x is
an output compare channel, CHxF is set when the value in the TIMB
counter registers matches the value in the TIMB channel x registers.
When CHxIE = 1, clear CHxF by reading TIMB channel x status and
control register with CHxF set, and then writing a logic 0 to CHxF. If
another interrupt request occurs before the clearing sequence is
complete, then writing logic 0 to CHxF has no effect. Therefore, an
interrupt request cannot be lost due to inadvertent clearing of CHxF.
Reset clears the CHxF bit. Writing a logic 1 to CHxF has no effect.
1 = Input capture or output compare on channel x
0 = No input capture or output compare on channel x
CHxIE — Channel x Interrupt Enable Bit
This read/write bit enables TIMB CPU interrupts on channel x.
Reset clears the CHxIE bit.
1 = Channel x CPU interrupt requests enabled
0 = Channel x CPU interrupt requests disabled
MSxB — Mode Select Bit B
This read/write bit selects buffered output compare/PWM operation.
MSxB exists only in the TIMB channel 0.
Setting MS0B disables the channel 1 status and control register and
reverts TBCH1 to general-purpose I/O.
Reset clears the MSxB bit.
1 = Buffered output compare/PWM operation enabled
0 = Buffered output compare/PWM operation disabled
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Freescale Semiconductor
Timer Interface Module B (TIMB)
MSxA — Mode Select Bit A
When ELSxB:A ≠ 00, this read/write bit selects either input capture
operation or unbuffered output compare/PWM operation (see Table
18-2).
1 = Unbuffered output compare/PWM operation
0 = Input capture operation
When ELSxB:A = 00, this read/write bit selects the initial output level
of the TBCHx pin once PWM, input capture or output compare
operation is enabled (see Table 18-2). Reset clears the MSxA bit.
1 = Initial output level low
0 = Initial output level high
NOTE:
Before changing a channel function by writing to the MSxB or MSxA bit,
set the TSTOP and TRST bits in the TIMB status and control register
(TBSC).
ELSxB and ELSxA — Edge/Level Select Bits
When channel x is an input capture channel, these read/write bits
control the active edge-sensing logic on channel x.
When channel x is an output compare channel, ELSxB and ELSxA
control the channel x output behavior when an output compare
occurs.
When ELSxB and ELSxA are both clear, channel x is not connected
to port F and pin PTFx/TBCHx is available as a general-purpose I/O
pin. However, channel x is at a state determined by these bits and
becomes transparent to the respective pin when PWM, input capture,
or output compare mode is enabled. Table 18-2 shows how ELSxB
and ELSxA work. Reset clears the ELSxB and ELSxA bits.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module B (TIMB)
301
Timer Interface Module B (TIMB)
Table 18-2. Mode, Edge, and Level Selection
MSxB:MSxA
ELSxB:ELSxA
X0
00
Mode
Output
Preset
NOTE:
X1
00
00
01
00
10
00
11
01
01
01
10
01
11
1X
01
1X
10
1X
11
Configuration
Pin under Port Control;
Initialize Timer
Output Level High
Pin under Port Control;
Initialize Timer
Output Level Low
Capture on Rising Edge Only
Input
Capture
Capture on Falling Edge Only
Capture on Rising or Falling Edge
Output
Compare
or PWM
Buffered
Output
Compare
or Buffered
PWM
Toggle Output on Compare
Clear Output on Compare
Set Output on Compare
Toggle Output on Compare
Clear Output on Compare
Set Output on Compare
Before enabling a TIMB channel register for input capture operation,
make sure that the PTFx/TBCHx pin is stable for at least two bus clocks.
TOVx — Toggle-On-Overflow Bit
When channel x is an output compare channel, this read/write bit
controls the behavior of the channel x output when the TIMB counter
overflows. When channel x is an input capture channel, TOVx has no
effect. Reset clears the TOVx bit.
1 = Channel x pin toggles on TIMB counter overflow.
0 = Channel x pin does not toggle on TIMB counter overflow.
NOTE:
When TOVx is set, a TIMB counter overflow takes precedence over a
channel x output compare if both occur at the same time.
Technical Data
302
MC68HC08AZ60A — Rev 2.1
Timer Interface Module B (TIMB)
Freescale Semiconductor
Timer Interface Module B (TIMB)
CHxMAX — Channel x Maximum Duty Cycle Bit
When the TOVx bit is at logic 1, setting the CHxMAX bit forces the
duty cycle of buffered and unbuffered PWM signals to 100%. As
Figure 18-8 shows, the CHxMAX bit takes effect in the cycle after it
is set or cleared. The output stays at the 100% duty cycle level until
the cycle after CHxMAX is cleared.
OVERFLOW
OVERFLOW
OVERFLOW
OVERFLOW
OVERFLOW
PERIOD
PTEx/TCHx
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
CHxMAX
Figure 18-8. CHxMAX Latency
18.9.5 TIMB Channel Registers
These read/write registers contain the captured TIMB counter value of
the input capture function or the output compare value of the output
compare function. The state of the TIMB channel registers after reset is
unknown.
In input capture mode (MSxB–MSxA = 0:0) reading the high byte of the
TIMB channel x registers (TBCHxH) inhibits input captures until the low
byte (TBCHxL) is read.
In output compare mode (MSxB–MSxA ≠ 0:0) writing to the high byte of
the TIMB channel x registers (TBCHxH) inhibits output compares and
the CHxF bit until the low byte (TBCHxL) is written.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module B (TIMB)
303
Timer Interface Module B (TIMB)
Register Name and Address TBCH0H — $0046
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TBCH0L — $0047
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset:
Indeterminate after Reset
Register Name and Address TBCH1H — $0049
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TBCH1L — $004A
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Indeterminate after Reset
Figure 18-9. TIMB Channel Registers
(TBCH0H/L–TBCH1H/L)
Technical Data
304
MC68HC08AZ60A — Rev 2.1
Timer Interface Module B (TIMB)
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 19. Programmable Interrupt Timer (PIT)
19.1 Contents
19.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
19.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .306
19.4
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
19.5
PIT Counter Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
19.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
19.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
19.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
19.7
PIT During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . 308
19.8 I/O Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .309
19.8.1 PIT Status and Control Register . . . . . . . . . . . . . . . . . . . 309
19.8.2 PIT Counter Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
19.8.3 PIT Counter Modulo Registers . . . . . . . . . . . . . . . . . . . . 313
19.2 Introduction
This section describes the Programmable Interrupt Timer (PIT) which is
a periodic interrupt timer whose counter is clocked internally via software
programmable options. Figure 19-1 is a block diagram of the PIT.
For further information regarding timers on M68HC08 family devices,
please consult the HC08 Timer Reference Manual, TIM08RM/AD.
MC68HC08AZ60A — Rev 2.1
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Technical Data
Programmable Interrupt Timer (PIT)
305
Programmable Interrupt Timer (PIT)
19.3 Features
Features of the PIT include:
•
Programmable PIT Clock Input
•
Free-Running or Modulo Up-Count Operation
•
PIT Counter Stop and Reset Bits
19.4 Functional Description
Figure 19-1 shows the structure of the PIT. The central component of
the PIT is the 16-bit PIT counter that can operate as a free-running
counter or a modulo up-counter. The counter provides the timing
reference for the interrupt. The PIT counter modulo registers,
PMODH–PMODL, control the modulo value of the counter. Software can
read the counter value at any time without affecting the counting
sequence.
INTERNAL
BUS CLOCK
PRESCALER
CSTOP
PRESCALER SELECT
PPS2
CRST
PPS1
PPS0
16-BIT COUNTER
POF
POIE
INTERRUPT
LOGIC
16-BIT COMPARATOR
PMODH:PMODL
Figure 19-1. PIT Block Diagram
Technical Data
306
MC68HC08AZ60A — Rev 2.1
Programmable Interrupt Timer (PIT)
Freescale Semiconductor
Programmable Interrupt Timer (PIT)
Register Name
Bit 7
6
5
POIE
PSTOP
4
3
0
0
2
1
Bit 0
PPS2
PPS1
PPS0
Read:
PIT Status and Control Register
Write:
(PSC)
Reset:
POF
0
0
1
0
0
0
0
0
Read:
PIT Counter Register High
Write:
(PCNTH)
Reset:
Bit 15
14
13
12
11
10
9
Bit 8
0
0
0
0
0
0
0
0
Read:
PIT Counter Register Low
Write:
(PCNTL)
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
Bit 15
14
13
12
11
10
9
Bit 8
1
1
1
1
1
1
1
1
Bit 7
6
5
4
3
2
1
Bit 0
1
1
1
1
1
1
1
1
Read:
PIT Counter Modulo Register High
Write:
(PMODH)
Reset:
Read:
PIT Counter Modulo Register Low
Write:
(PMODL)
Reset:
0
PRST
=Unimplemented
Figure 19-2. PIT I/O Register Summary
Table 19-1. PIT I/O Register Address Summary
Register
PSC
PCNTH
PCNTL
PMODH
PMODL
Address
$004B
$004C
$004D
$004E
$004F
19.5 PIT Counter Prescaler
The clock source can be one of the seven prescaler outputs. The
prescaler generates seven clock rates from the internal bus clock. The
prescaler select bits, PPS[2:0], in the status and control register select
the PIT clock source.
The value in the PIT counter modulo registers and the selected prescaler
output determines the frequency of the periodic interrupt. The PIT
overflow flag (POF) is set when the PIT counter value reaches the
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Programmable Interrupt Timer (PIT)
307
Programmable Interrupt Timer (PIT)
modulo value programmed in the PIT counter modulo registers. The PIT
interrupt enable bit, POIE, enables PIT overflow CPU interrupt requests.
POF and POIE are in the PIT status and control register.
19.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
19.6.1 Wait Mode
The PIT remains active after the execution of a WAIT instruction. In wait
mode the PIT registers are not accessible by the CPU. Any enabled CPU
interrupt request from the PIT can bring the MCU out of wait mode.
If PIT functions are not required during wait mode, reduce power
consumption by stopping the PIT before executing the WAIT instruction.
19.6.2 Stop Mode
The PIT is inactive after the execution of a STOP instruction. The STOP
instruction does not affect register conditions or the state of the PIT
counter. PIT operation resumes when the MCU exits stop mode after an
external interrupt.
19.7 PIT During Break Interrupts
A break interrupt stops the PIT counter.
The system integration module (SIM) controls whether status bits in
other modules can be cleared during the break state. The BCFE bit in
the SIM break flag control register (SBFCR) enables software to clear
status bits during the break state (see SIM Break Flag Control Register
(SBFCR) on page 137).
Technical Data
308
MC68HC08AZ60A — Rev 2.1
Programmable Interrupt Timer (PIT)
Freescale Semiconductor
Programmable Interrupt Timer (PIT)
To allow software to clear status bits during a break interrupt, write a
logic 1 to the BCFE bit. If a status bit is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect status bits during the break state, write a logic 0 to the BCFE
bit. With BCFE at logic 0 (its default state), software can read and write
I/O registers during the break state without affecting status bits. Some
status bits have a 2-step read/write clearing procedure. If software does
the first step on such a bit before the break, the bit cannot change during
the break state as long as BCFE is at logic 0. After the break, doing the
second step clears the status bit.
19.8 I/O Registers
The following I/O registers control and monitor operation of the PIT:
•
PIT status and control register (PSC)
•
PIT counter registers (PCNTH–PCNTL)
•
PIT counter modulo registers (PMODH–PMODL)
19.8.1 PIT Status and Control Register
The PIT status and control register:
•
Enables PIT interrupt
•
Flags PIT overflows
•
Stops the PIT counter
•
Resets the PIT counter
•
Prescales the PIT counter clock
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Programmable Interrupt Timer (PIT)
309
Programmable Interrupt Timer (PIT)
Address:
$004B
Bit 7
Read:
POF
Write:
0
Reset:
0
6
5
POIE
PSTOP
0
1
4
3
0
0
PRST
0
0
2
1
Bit 0
PPS2
PPS1
PPS0
0
0
0
= Unimplemented
Figure 19-3. PIT Status and Control Register (PSC)
POF — PIT Overflow Flag Bit
This read/write flag is set when the PIT counter reaches the modulo
value programmed in the PIT counter modulo registers. Clear POF by
reading the PIT status and control register when POF is set and then
writing a logic 0 to POF. If another PIT overflow occurs before the
clearing sequence is complete, then writing logic 0 to POF has no
effect. Therefore, a POF interrupt request cannot be lost due to
inadvertent clearing of POF. Reset clears the POF bit. Writing a logic
1 to POF has no effect.
1 = PIT counter has reached modulo value
0 = PIT counter has not reached modulo value
POIE — PIT Overflow Interrupt Enable Bit
This read/write bit enables PIT overflow interrupts when the POF bit
becomes set. Reset clears the POIE bit.
1 = PIT overflow interrupts enabled
0 = PIT overflow interrupts disabled
PSTOP — PIT Stop Bit
This read/write bit stops the PIT counter. Counting resumes when
PSTOP is cleared. Reset sets the PSTOP bit, stopping the PIT
counter until software clears the PSTOP bit.
1 = PIT counter stopped
0 = PIT counter active
Technical Data
310
MC68HC08AZ60A — Rev 2.1
Programmable Interrupt Timer (PIT)
Freescale Semiconductor
Programmable Interrupt Timer (PIT)
NOTE:
Do not set the PSTOP bit before entering wait mode if the PIT is required
to exit wait mode.
PRST — PIT Reset Bit
Setting this write-only bit resets the PIT counter and the PIT prescaler.
Setting PRST has no effect on any other registers. Counting resumes
from $0000. PRST is cleared automatically after the PIT counter is
reset and always reads as logic zero. Reset clears the PRST bit.
1 = Prescaler and PIT counter cleared
0 = No effect
NOTE:
Setting the PSTOP and PRST bits simultaneously stops the PIT counter
at a value of $0000.
PPS[2:0] — Prescaler Select Bits
These read/write bits select one of the seven prescaler outputs as the
input to the PIT counter as Table 19-2 shows. Reset clears the
PPS[2:0] bits.
Table 19-2. Prescaler Selection
PPS[2:0]
PIT Clock Source
000
Internal Bus Clock ÷1
001
Internal Bus Clock ÷ 2
010
Internal Bus Clock ÷ 4
011
Internal Bus Clock ÷ 8
100
Internal Bus Clock ÷ 16
101
Internal Bus Clock ÷ 32
110
Internal Bus Clock ÷ 64
111
Internal Bus Clock ÷ 64
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Programmable Interrupt Timer (PIT)
311
Programmable Interrupt Timer (PIT)
19.8.2 PIT Counter Registers
The two read-only PIT counter registers contain the high and low bytes
of the value in the PIT counter. Reading the high byte (PCNTH) latches
the contents of the low byte (PCNTL) into a buffer. Subsequent reads of
PCNTH do not affect the latched PCNTL value until PCNTL is read.
Reset clears the PIT counter registers. Setting the PIT reset bit (PRST)
also clears the PIT counter registers.
NOTE:
If you read PCNTH during a break interrupt, be sure to unlatch PCNTL
by reading PCNTL before exiting the break interrupt. Otherwise, PCNTL
retains the value latched during the break.
Address: $004C
Read:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
14
13
12
11
10
9
Bit 8
0
0
0
0
0
0
0
0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
14
13
12
11
10
9
Bit 8
0
0
0
0
0
0
0
0
Write:
Reset:
Address: $004D
Read:
Write:
Reset:
= Unimplemented
Figure 19-4. PIT Counter Registers (PCNTH–PCNTL)
Technical Data
312
MC68HC08AZ60A — Rev 2.1
Programmable Interrupt Timer (PIT)
Freescale Semiconductor
Programmable Interrupt Timer (PIT)
19.8.3 PIT Counter Modulo Registers
The read/write PIT modulo registers contain the modulo value for the PIT
counter. When the PIT counter reaches the modulo value the overflow
flag (POF) becomes set and the PIT counter resumes counting from
$0000 at the next timer clock. Writing to the high byte (PMODH) inhibits
the POF bit and overflow interrupts until the low byte (PMODL) is written.
Reset sets the PIT counter modulo registers.
Address: $004E:$004F
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
14
13
12
11
10
9
Bit 8
1
1
1
1
1
1
1
1
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
1
1
1
1
1
1
1
1
Address: $004E:$004F
Read:
Write:
Reset:
Figure 19-5. PIT Counter Modulo Registers (PMODH–PMODL)
NOTE:
Reset the PIT counter before writing to the PIT counter modulo registers.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Programmable Interrupt Timer (PIT)
313
Programmable Interrupt Timer (PIT)
Technical Data
314
MC68HC08AZ60A — Rev 2.1
Programmable Interrupt Timer (PIT)
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 20. I/O Ports
20.1 Contents
20.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
20.3 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
20.3.1 Port A Data Register (PTA) . . . . . . . . . . . . . . . . . . . . . . .317
20.3.2 Data Direction Register A (DDRA) . . . . . . . . . . . . . . . . . 318
20.4 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
20.4.1 Port B Data Register (PTB) . . . . . . . . . . . . . . . . . . . . . . .320
20.4.2 Data Direction Register B (DDRB) . . . . . . . . . . . . . . . . . 321
20.5 Port C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
20.5.1 Port C Data Register (PTC) . . . . . . . . . . . . . . . . . . . . . . .323
20.5.2 Data Direction Register C (DDRC) . . . . . . . . . . . . . . . . . 324
20.6 Port D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
20.6.1 Port D Data Register (PTD) . . . . . . . . . . . . . . . . . . . . . . .326
20.6.2 Data Direction Register D (DDRD) . . . . . . . . . . . . . . . . . 327
20.7 Port E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
20.7.1 Port E Data Register (PTE) . . . . . . . . . . . . . . . . . . . . . . .329
20.7.2 Data Direction Register E (DDRE). . . . . . . . . . . . . . . . . . 332
20.8 Port F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
20.8.1 Port F Data Register (PTF). . . . . . . . . . . . . . . . . . . . . . . . 334
20.8.2 Data Direction Register F (DDRF) . . . . . . . . . . . . . . . . . . 335
20.9 Port G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
20.9.1 Port G Data Register (PTG) . . . . . . . . . . . . . . . . . . . . . . . 337
20.9.2 Data Direction Register G (DDRG) . . . . . . . . . . . . . . . . . 338
20.10 Port H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
20.10.1 Port H Data Register (PTH) . . . . . . . . . . . . . . . . . . . . . . .340
20.10.2 Data Direction Register H (DDRH) . . . . . . . . . . . . . . . . . 341
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
I/O Ports
315
I/O Ports
20.2 Introduction
Fifty bidirectional input-output (I/O) pins form eight parallel ports. All I/O
pins are programmable as inputs or outputs.
NOTE:
Connect any unused I/O pins to an appropriate logic level, either VDD or
VSS. Although the I/O ports do not require termination for proper
operation, termination reduces excess current consumption and the
possibility of electrostatic damage.
Table 20-1. I/O Port Register Summary
Register Name
Bit 7
6
5
4
3
2
1
Port A Data Register (PTA)
PTA7
PTA6
PTA5
PTA4
PTA3
PTA2
PTA1
PTA0 $0000
Port B Data Register (PTB)
PTB7
PTB6
PTB5
PTB4
PTB3
PTB2
PTB1
PTB0 $0001
0
0
PTC5
PTC4
PTC3
PTC2
PTC1
PTC0 $0002
PTD7
PTD6
PTD5
PTD4
PTD3
PTD2
PTD1
PTD0 $0003
Port C Data Register (PTC)
R:
Bit 0
Addr.
W:
Port D Data Register (PTD)
Data Direction Register A (DDRA)
DDRA7 DDRA6 DDRA5 DDRA4 DDRA3 DDRA2 DDRA1 DDRA0 $0004
Data Direction Register B (DDRB)
DDRB7 DDRB6 DDRB5 DDRB4 DDRB3 DDRB2 DDRB1 DDRB0 $0005
Data Direction Register C (DDRC)
R:
MCLKEN
0
DDRC5 DDRC4 DDRC3 DDRC2 DDRC1 DDRC0 $0006
W:
Data Direction Register D (DDRD)
DDRD7 DDRD6 DDRD5 DDRD4 DDRD3 DDR2 DDRD1 DDRD0 $0007
Port E Data Register (PTE)
Port F Data Register (PTF)
PTE7
R:
PTE6
PTE5
PTE4
PTE3
PTE2
PTE1
PTE0 $0008
PTF6
PTF5
PTF4
PTF3
PTF2
PTF1
PTF0 $0009
0
0
0
0
0
PTG2
PTG1
PTG0 $000A
0
0
0
0
0
PTH1
PTH0 $000B
0
W:
Port G Data Register (PTG)
R:
W:
Port H Data Register (PTH)
R:
0
W:
Data Direction Register E (DDRE)
Data Direction Register F (DDRF)
DDRE7 DDRE6 DDRE5 DDRE4 DDRE3 DDRE2 DDRE1 DDRE0 $000C
R:
0
DDRF6 DDRF5 DDRF4 DDRF3 DDRF2 DDRF1 DDRF0 $000D
W:
Technical Data
316
MC68HC08AZ60A — Rev 2.1
I/O Ports
Freescale Semiconductor
I/O Ports
Table 20-1. I/O Port Register Summary (Continued)
Register Name
R:
Data Direction Register G (DDRG)
Bit 7
6
5
4
3
0
0
0
0
0
0
0
0
0
0
2
1
Bit 0
Addr.
DDRG2 DDRG1 DDRG0 $000E
W:
R:
Data Direction Register H (DDRH)
0
DDRH1 DDRH0 $000F
W:
= Unimplemented
20.3 Port A
Port A is an 8-bit general-purpose bidirectional I/O port.
20.3.1 Port A Data Register (PTA)
The port A data register contains a data latch for each of the eight port
A pins.
PTA
$0000
Bit 7
6
5
4
3
2
1
Bit 0
PTA7
PTA6
PTA5
PTA4
PTA3
PTA2
PTA1
PTA0
Read:
Write:
Reset:
Unaffected by reset
Figure 20-1. Port A data register (PTA)
PTA[7:0] — Port A Data Bits
These read/write bits are software programmable. Data direction of
each port A pin is under the control of the corresponding bit in data
direction register A. Reset has no effect on port A data.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
I/O Ports
317
I/O Ports
20.3.2 Data Direction Register A (DDRA)
Data direction register A determines whether each port A pin is an input
or an output. Writing a logic one to a DDRA bit enables the output buffer
for the corresponding port A pin; a logic zero disables the output buffer.
DDRA
$0004
Bit 7
6
5
4
3
2
1
Bit 0
DDRA7
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
DDRA1
DDRA0
0
0
0
0
0
0
0
0
Read:
Write:
Reset:
Figure 20-2 Data Direction Register A (DDRA)
DDRA[7:0] — Data direction register A Bits
These read/write bits control port A data direction. Reset clears
DDRA[7:0], configuring all port A pins as inputs.
1 = Corresponding port A pin configured as output
0 = Corresponding port A pin configured as input
NOTE:
Avoid glitches on port A pins by writing to the port A data register before
changing data direction register A bits from 0 to 1.
Figure 20-3 shows the port A I/O logic.
INTERNAL DATA BUS
READ DDRA ($0004)
WRITE DDRA ($0004)
RESET
DDRAx
WRITE PTA ($0000)
PTAx
PTAx
READ PTA ($0000)
Figure 20-3. Port A I/O Circuit
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When bit DDRAx is a logic one, reading address $0000 reads the PTAx
data latch. When bit DDRAx is a logic zero, reading address $0000
reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 20-2 summarizes
the operation of the port A pins.
Table 20-2. Port A pin functions
DDRA Bit
PTA Bit
I/O Pin Mode
Accesses to
DDRA
Accesses to PTA
Read/Write
Read
Write
0
X(1)
Input, Hi-Z(2)
DDRA[7:0]
Pin
PTA[7:0](3)
1
X
Output
DDRA[7:0]
PTA[7:0]
PTA[7:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
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20.4 Port B
Port B is an 8-bit special function port that shares all of its pins with the
analog to digital convertor.
20.4.1 Port B Data Register (PTB)
The port B data register contains a data latch for each of the eight port
B pins.
PTB
$0001
Bit 7
6
5
4
3
2
1
Bit 0
PTB7
PTB6
PTB5
PTB4
PTB3
PTB2
PTB1
PTB0
ATD2
ATD1
ATD0
Read:
Write:
Reset:
ALTERNATE
FUNCTIONS
Unaffected by reset
ATD7
ATD6
ATD5
ATD4
ATD3
Figure 20-4. Port B Data Register (PTB)
PTB[7:0] — Port B Data Bits
These read/write bits are software programmable. Data direction of
each port B pin is under the control of the corresponding bit in data
direction register B. Reset has no effect on port B data.
ATD[7:0] — ADC Channels
NOTE:
PTB7/ATD7– PTB0/ATD0 are eight of the analog to digital converter
channels. The ADC channel select bits, CH[4:0], determine whether the
PTB7/ATD7–PTB0/ATD0 pins are ADC channels or general-purpose
I/O pins. If an ADC channel is selected and a read of this corresponding
bit in the port B data register occurs, the data will be zero if the data
direction for this bit is programmed as an input. Otherwise, the data will
reflect the value in the data latch. Data direction register B (DDRB) does
not affect the data direction of port B pins that are being used by the
ADC. However, the DDRB bits always determine whether reading port B
returns the states of the latches or logic 0.
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20.4.2 Data Direction Register B (DDRB)
Data direction register B determines whether each port B pin is an input
or an output. Writing a logic one to a DDRB bit enables the output buffer
for the corresponding port B pin; a logic zero disables the output buffer.
DDRB
$0005
Bit 7
6
5
4
3
2
1
Bit 0
DDRB7
DDRB6
DDRB5
DDRB4
DDRB3
DDRB2
DDRB1
DDRB0
0
0
0
0
0
0
0
0
Read:
Write:
Reset:
Figure 20-5. Data Direction Register B (DDRB)
DDRB[7:0] — Data Direction Register B Bits
These read/write bits control port B data direction. Reset clears
DDRB[7:0], configuring all port B pins as inputs.
1 = Corresponding port B pin configured as output
0 = Corresponding port B pin configured as input
NOTE:
Avoid glitches on port B pins by writing to the port B data register before
changing data direction register B bits from 0 to 1.
Figure 20-6 shows the port B I/O logic.
INTERNAL DATA BUS
READ DDRB ($0005)
WRITE DDRB ($0005)
RESET
DDRBx
WRITE PTB ($0001)
PTBx
PTBx
READ PTB ($0001)
Figure 20-6. Port B I/O Circuit
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When bit DDRBx is a logic one, reading address $0001 reads the PTBx
data latch. When bit DDRBx is a logic zero, reading address $0001
reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 20-3 summarizes
the operation of the port B pins.
Table 20-3. Port B Pin Functions
DDRB Bit
PTB Bit
I/O Pin Mode
Accesses to
DDRB
Accesses to PTB
Read/Write
Read
Write
0
X(1)
Input, Hi-Z(2)
DDRB[7:0]
Pin
PTB[7:0](3)
1
X
Output
DDRB[7:0]
PTB[7:0]
PTB[7:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
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20.5 Port C
Port C is a 6-bit general-purpose bidirectional I/O port.
20.5.1 Port C Data Register (PTC)
The port C data register contains a data latch for each of the six port C
pins.
PTC
$0002
Read:
Bit 7
6
0
0
5
4
3
2
1
Bit 0
PTC5
PTC4
PTC3
PTC2
PTC1
PTC0
Write:
Reset:
Unaffected by reset
ALTERNATE
FUNCTIONS
MCLK
= Unimplemented
Figure 20-7. Port C Data Register (PTC)
PTC[5:0] — Port C Data Bits
These read/write bits are software-programmable. Data direction of
each port C pin is under the control of the corresponding bit in data
direction register C. Reset has no effect on port C data.
MCLK — System Clock Bit
The system clock is driven out of PTC2 when enabled by MCLKEN in
PTC DDR7.
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20.5.2 Data Direction Register C (DDRC)
Data direction register C determines whether each port C pin is an input
or an output. Writing a logic one to a DDRC bit enables the output buffer
for the corresponding port C pin; a logic zero disables the output buffer.
Bit 7
DDRC
$0006
6
5
4
3
2
1
Bit 0
DDRC5
DDRC4
DDRC3
DDRC2
DDRC1
DDRC0
0
0
0
0
0
0
0
Read:
MCLKEN
Write:
Reset:
0
0
= Unimplemented
Figure 20-8. Data Direction Register C (DDRC)
MCLKEN — MCLK Enable Bit
This read/write bit enables MCLK to be an output signal on PTC2. If
MCLK is enabled, DDRC2 has no effect. Reset clears this bit.
1 = MCLK output enabled
0 = MCLK output disabled
DDRC[5:0] — Data Direction Register C Bits
These read/write bits control port C data direction. Reset clears
DDRC[7:0], configuring all port C pins as inputs.
1 = Corresponding port C pin configured as output
0 = Corresponding port C pin configured as input
NOTE:
Avoid glitches on port C pins by writing to the port C data register before
changing data direction register C bits from 0 to 1.
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Figure 20-9 shows the port C I/O logic.
.
INTERNAL DATA BUS
READ DDRC ($0006)
WRITE DDRC ($0006)
DDRCx
RESET
WRITE PTC ($0002)
PTCx
PTCx
READ PTC ($0002)
Figure 20-9. Port C I/O Circuit
When bit DDRCx is a logic one, reading address $0002 reads the PTCx
data latch. When bit DDRCx is a logic zero, reading address $0002
reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 20-4 summarizes
the operation of the port C pins.
Table 20-4. Port C Pin Functions
DDRC bit
PTC Bit
I/O Pin Mode
Accesses to
DDRC
Accesses to PTC
Read/Write
Read
Write
0
2
Input, Hi-Z
DDRC[7]
Pin
PTC2
1
2
Output
DDRC[7]
0
—
0
X(1)
Input, Hi-Z(2)
DDRC[5:0]
Pin
PTC[5:0](3)
1
X
Output
DDRC[5:0]
PTC[5:0]
PTC[5:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
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20.6 Port D
Port D is an 8 -bit special function port that shares seven of it’s pins with
the analog to digital converter and two with the TIMA and TIMB modules
20.6.1 Port D Data Register (PTD)
The port D data register contains a data latch for each of the eight port
D pins.
PTD
$0003
Bit 7
6
5
4
3
2
1
Bit 0
PTD7
PTD6
PTD5
PTD4
PTD3
PTD2
PTD1
PTD0
ATD10
ATD9
ATD8
Read:
Write:
Reset:
Alternate
Functions
Unaffected by reset
R
ATD14/
TACLK
ATD13
ATD12/
TBCLK
ATD11
Figure 20-10. Port D Data Register (PTD)
PTD[7:0] — Port D Data Bits
PTD[7:0] are read/write, software programmable bits. Data direction
of PTD[7:0] pins are under the control of the corresponding bit in data
direction register D.
ATD[14:8] — ADC Channel Status Bits
PTD6/ATD14/TACLK–PTD0/ATD8 are seven of the 15 analog-to-digital
converter channels. The ATD channel select bits, CH[4:0], determine
whether the PTD6/ATD14/TACLK–PTD0/ATD8 pins are ADC channels
or general purpose I/O pins. If an ADC channel is selected and a read of
this corresponding bit in the port B data register occurs, the data will be
0 if the data direction for this bit is programmed as an input. Otherwise
the data will reflect the value in the data latch.
NOTE:
Data direction register D (DDRD) does not affect the data direction of
port D pins that are being used by the TIMA or TIMB. However, the
DDRD bits always determine whether reading port D returns the states
of the latches to logic 0.
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TACLK/TBCLK — Timer clock input
The PTD6/ATD14/TACLK pin is the external clock input for the TIMA.
The PTD4/TBCLK pin is the external clock input for the TIMB.The
prescaler select bits, PS[2:0], select PTD6/ATD14/TACLK or
PTD4/TBCLK as the TIM clock input (see TIMA Channel Status and
Control Registers on page 424 and TIMB Status and Control
Register on page 295). When not selected as the TIM clock,
PTD6/TAClk and PTD4/TBCLK are available for general purpose I/O.
While TACLK/TBCLK are selected, corresponding DDRD bits have
no effect.
20.6.2 Data Direction Register D (DDRD)
Data direction register D determines whether each port D pin is an input
or an output. Writing a logic one to a DDRD bit enables the output buffer
for the corresponding port D pin; a logic zero disables the output buffer.
DDRD
$0007
Bit 7
6
5
4
3
2
1
Bit 0
DDRD7
DDRD6
DDRD5
DDRD4
DDRD3
DDRD2
DDRD1
DDRD0
0
0
0
0
0
0
0
0
Read:
Write:
Reset:
Figure 20-11. Data Direction Register D (DDRD)
DDRD[7:0] — Data Direction Register D Bits
These read/write bits control port D data direction. Reset clears
DDRD[7:0], configuring all port D pins as inputs.
1 = Corresponding port D pin configured as output
0 = Corresponding port D pin configured as input
NOTE:
Avoid glitches on port D pins by writing to the port D data register before
changing data direction register D bits from 0 to 1.
Figure 20-12 shows the port D I/O logic.
When bit DDRDx is a logic one, reading address $0003 reads the PTDx
data latch. When bit DDRDx is a logic zero, reading address $0003
reads the voltage level on the pin. The data latch can always be written,
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READ DDRD ($0007)
INTERNAL DATA BUS
WRITE DDRD ($0007)
DDRDx
RESET
WRITE PTD ($0003)
PTDx
PTDx
READ PTD ($0003)
Figure 20-12. Port D I/O Circuit
regardless of the state of its data direction bit. Table 20-5 summarizes
the operation of the port D pins.
Table 20-5. Port D Pin Functions
DDRD Bit
PTD Bit
I/O Pin Mode
Accesses to
DDRD
Accesses to PTD
Read/Write
Read
Write
0
X(1)
Input, Hi-Z(2)
DDRD[7:0]
Pin
PTD[7:0](3)
1
X
Output
DDRD[7:0]
PTD[7:0]
PTD[7:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
Technical Data
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20.7 Port E
Port E is an 8-bit special function port that shares two of its pins with the
timer interface module (TIMA), two of its pins with the serial
communications interface module (SCI) and four of its pins with the
serial peripheral interface module (SPI).
20.7.1 Port E Data Register (PTE)
The port E data register contains a data latch for each of the eight port
E pins.
Bit 7
6
5
4
3
2
1
Bit 0
PTE7
PTE6
PTE5
PTE4
PTE3
PTE2
PTE1
PTE0
TACH0
RxD
TxD
Read:
PTE
$0008
Write:
Reset:
Unaffected by reset
Alternate
SPSCK
Function:
MOSI
MISO
SS
TACH1
Figure 20-13. Port E Data Register (PTE)
PTE[7:0] — Port E Data Bits
PTE[7:0] are read/write, software programmable bits. Data direction
of each port E pin is under the control of the corresponding bit in data
direction register E.
SPSCK — SPI Serial Clock
The PTE7/SPSCK pin is the serial clock input of a SPI slave module
and serial clock output of a SPI master modules. When the SPE bit is
clear, the PTE7/SPSCK pin is available for general-purpose I/O.
MOSI — Master Out/Slave In
The PTE6/MOSI pin is the master out/slave in terminal of the SPI
module. When the SPE bit is clear, the PTE6/MOSI pin is available for
general-purpose I/O. See SPI Control Register (SPCR).
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MISO — Master In/Slave Out
The PTE5/MISO pin is the master in/slave out terminal of the SPI
module. When the SPI enable bit, SPE, is clear, the SPI module is
disabled, and the PTE5/MISO pin is available for general-purpose
I/O. See SPI Control Register (SPCR).
SS — Slave Select
The PTE4/SS pin is the slave select input of the SPI module. When
the SPE bit is clear, or when the SPI master bit, SPMSTR, is set and
MODFEN bit is low, the PTE4/SS pin is available for general-purpose
I/O. See SPI Control Register (SPCR). When the SPI is enabled as
a slave, the DDRF0 bit in data direction register E (DDRE) has no
effect on the PTE4/SS pin.
NOTE:
Data direction register E (DDRE) does not affect the data direction of
port E pins that are being used by the SPI module. However, the DDRE
bits always determine whether reading port E returns the states of the
latches or the states of the pins. See Table 20-6.
TACH[1:0] — Timer A Channel I/O Bits
The PTE3/TACH1–PTE2/TACH0 pins are the TIMA input
capture/output compare pins. The edge/level select bits,
ELSxB:ELSxA, determine whether the PTE3/TACH1–PTE2/TACH0
pins are timer channel I/O pins or general-purpose I/O pins. See TIMA
Channel Status and Control Registers on page 424.
NOTE:
Data direction register E (DDRE) does not affect the data direction of
port E pins that are being used by the TIMA. However, the DDRE bits
always determine whether reading port E returns the states of the
latches or the states of the pins. See Table 20-6.
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RxD — SCI Receive Data Input
The PTE1/RxD pin is the receive data input for the SCI module. When
the enable SCI bit, ENSCI, is clear, the SCI module is disabled, and
the PTE1/RxD pin is available for general-purpose I/O. See SCI
Control Register 1.
TxD — SCI Transmit Data Output
The PTE0/TxD pin is the transmit data output for the SCI module.
When the enable SCI bit, ENSCI, is clear, the SCI module is disabled,
and the PTE0/TxD pin is available for general-purpose I/O. See SCI
Control Register 2.
NOTE:
Data direction register E (DDRE) does not affect the data direction of
port E pins that are being used by the SCI module. However, the DDRE
bits always determine whether reading port E returns the states of the
latches or the states of the pins. See Table 20-6.
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20.7.2 Data Direction Register E (DDRE)
Data direction register E determines whether each port E pin is an input
or an output. Writing a logic one to a DDRE bit enables the output buffer
for the corresponding port E pin; a logic zero disables the output buffer.
DDRE
$000C
Bit 7
6
5
4
3
2
1
Bit 0
DDRE7
DDRE6
DDRE5
DDRE4
DDRE3
DDRE2
DDRE1
DDRE0
0
0
0
0
0
0
0
0
Read:
Write:
Reset:
Figure 20-14. Data Direction Register E (DDRE)
DDRE[7:0] — Data Direction Register E Bits
These read/write bits control port E data direction. Reset clears
DDRE[7:0], configuring all port E pins as inputs.
1 = Corresponding port E pin configured as output
0 = Corresponding port E pin configured as input
NOTE:
Avoid glitches on port E pins by writing to the port E data register before
changing data direction register E bits from 0 to 1.
Figure 20-15 shows the port E I/O logic.
INTERNAL DATA BUS
READ DDRE ($000C)
WRITE DDRE ($000C)
RESET
DDREx
WRITE PTE ($0008)
PTEx
PTEx
READ PTE ($0008)
Figure 20-15. Port E I/O Circuit
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When bit DDREx is a logic one, reading address $0008 reads the PTEx
data latch. When bit DDREx is a logic zero, reading address $0008
reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 20-6 summarizes
the operation of the port E pins.
Table 20-6. Port E Pin Functions
DDRE Bit
PTE Bit
I/O Pin Mode
Accesses to
DDRE
Accesses to PTE
Read/Write
Read
Write
0
X(1)
Input, Hi-Z(2)
DDRE[7:0]
Pin
PTE[7:0](3)
1
X
Output
DDRE[7:0]
PTE[7:0]
PTE[7:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
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I/O Ports
20.8 Port F
Port F is a 7-bit special function port that shares four of its pins with the
timer interface module (TIMA) and two of its pins with the timer interface
module (TIMB)).
20.8.1 Port F Data Register (PTF)
The port F data register contains a data latch for each of the seven port
F pins.
Bit 7
PTF
$0009
Read:
6
5
4
3
2
1
Bit 0
PTF6
PTF5
PTF4
PTF3
PTF2
PTF1
PTF0
TACH4
TACH3
TACH2
0
Write:
Reset:
Alternate
Function:
Unaffected by reset
TBCH1
TBCH0
TACH5
= Unimplemented
Figure 20-16. Port F Data Register (PTF)
PTF[6:0] — Port F Data Bits
These read/write bits are software programmable. Data direction of
each port F pin is under the control of the corresponding bit in data
direction register F. Reset has no effect on PTF[6:0].
TACH[5:2] — Timer A Channel I/O Bits
The PTF3/TACH5–PTF0/TACH2 pins are the TIM input
capture/output compare pins. The edge/level select bits,
ELSxB:ELSxA, determine whether the PTF3/TACH5–PTF0/TACH2
pins are timer channel I/O pins or general-purpose I/O pins.
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TBCH[1:0] — Timer B Channel I/O Bits
The PTF5/TBCH1-PTF4/TBCH0 pins are the TIMB input
capture/output compare pins. The edge/level select bits,
ELSxB:ELSxA, determine whether the PTF5/TBCH1-PTF4/TBCH0
pins are timer channel I/O pins or general purpose I/O pins. See TIMB
Status and Control Register on page 295.
NOTE:
Data direction register F(DDRF) does not affect the data direction of port
F pins that are being used by TIMA and TIMB. However, the DDRF bits
always determine whether reading port F returns the states of the
latches or the states of the pins. See Table 20-7.
20.8.2 Data Direction Register F (DDRF)
Data direction register F determines whether each port F pin is an input
or an output. Writing a logic one to a DDRF bit enables the output buffer
for the corresponding port F pin; a logic zero disables the output buffer.
Bit 7
DDRF
$000D
Read:
6
5
4
3
2
1
Bit 0
0
DDRF6 DDRF5 DDRF4 DDRF3 DDRF2 DDRF1 DDRF0
Write:
Reset:
0
0
0
0
0
0
0
= Unimplemented
Figure 20-17. Data Direction Register F (DDRF)
DDRF[6:0] — Data Direction Register F Bits
These read/write bits control port F data direction. Reset clears
DDRF[6:0], configuring all port F pins as inputs.
1 = Corresponding port F pin configured as output
0 = Corresponding port F pin configured as input
NOTE:
Avoid glitches on port F pins by writing to the port F data register before
changing data direction register F bits from 0 to 1.
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Figure 20-18 shows the port F I/O logic.
INTERNAL DATA BUS
READ DDRF ($000D)
WRITE DDRF ($000D)
DDRFx
RESET
WRITE PTF ($0009)
PTFx
PTFx
READ PTF ($0009)
Figure 20-18. Port F I/O Circuit
When bit DDRFx is a logic one, reading address $0009 reads the PTFx
data latch. When bit DDRFx is a logic zero, reading address $0009 reads
the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 20-7 summarizes
the operation of the port F pins.
Table 20-7. Port F Pin Functions
DDRF Bit
PTF Bit
I/O Pin Mode
Accesses to
DDRF
Accesses to PTF
Read/Write
Read
Write
0
X(1)
Input, Hi-Z(2)
DDRF[6:0]
Pin
PTF[6:0](3)
1
X
Output
DDRF[6:0]
PTF[6:0]
PTF[6:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
Technical Data
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20.9 Port G
Port G is a 3-bit special function port that shares all of its pins with the
Keyboard Interrupt Module (KBD).
20.9.1 Port G Data Register (PTG)
The port G data register contains a data latch for each of the three port
G pins.
Read:
Bit 7
6
5
4
3
0
0
0
0
0
PTG $000A
2
1
Bit 0
PTG2
PTG1
PTG0
KBD2
KBD1
KBD0
Write:
Reset:
Unaffected by reset
Alternate Function
= Unimplemented
Figure 20-19. Port G Data Register (PTG)
PTG[2:0] — Port G Data Bits
These read/write bits are software-programmable. Data direction of
each port G pin is under the control of the corresponding bit in data
direction register G. Reset has no effect on PTG[2:0].
KBD[2:0] — Keyboard Wakeup Pins
The keyboard interrupt enable bits, KBIE[2:0], in the keyboard
interrupt control register (KBICR), enable the port G pins as external
interrupt pins. See Keyboard Module (KBD) on page 395. Enabling
an external interrupt pin will override the corresponding DDRGx.
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I/O Ports
20.9.2 Data Direction Register G (DDRG)
Data direction register G determines whether each port G pin is an input
or an output. Writing a logic one to a DDRG bit enables the output buffer
for the corresponding port G pin; a logic zero disables the output buffer.
DDRG
$000E
Read:
Bit 7
6
5
4
3
0
0
0
0
0
2
1
Bit 0
DDRG2 DDRG1 DDRG0
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 20-20. Data Direction Register G (DDRG)
DDRG[2:0] — Data Direction Register G Bits
These read/write bits control port G data direction. Reset clears
DDRG[2:0], configuring all port G pins as inputs.
1 = Corresponding port G pin configured as output
0 = Corresponding port G pin configured as input
NOTE:
Avoid glitches on port G pins by writing to the port G data register before
changing data direction register G bits from 0 to 1.
Figure 20-21 shows the port G I/O logic.
INTERNAL DATA BUS
READ DDRG ($000E)
WRITE DDRG ($000E)
RESET
DDRGx
WRITE PTG ($000A)
PTGx
PTGx
READ PTG ($000A)
Figure 20-21. Port G I/O Circuit
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When bit DDRGx is a logic one, reading address $000A reads the PTGx
data latch. When bit DDRGx is a logic zero, reading address $000A
reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data. Table 20-8 summarises the operation
of the port G pins.
Table 20-8. Port G Pin Functions
DDRG Bit
PTG Bit
I/O Pin Mode
Accesses to
DDRG
Accesses to PTG
Read/Write
Read
Write
0
X(1)
Input, Hi-Z(2)
DDRG[2:0]
Pin
PTG[2:0](3)
1
X
Output
DDRG[2:0]
PTG[2:0]
PTG[2:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
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20.10 Port H
Port H is a 2-bit special function port that shares all of its pins with the
Keyboard Interrupt Module (KBD).
20.10.1 Port H Data Register (PTH)
The port H data register contains a data latch for each of the two port H
pins.
Read:
Bit 7
6
5
4
3
2
0
0
0
0
0
0
PTH $000B
1
Bit 0
PTH1
PTH0
KBD4
KBD3
Write:
Reset:
Unaffected by reset
Alternate Function
= Unimplemented
Figure 20-22. Port H Data Register (PTH)
PTH[1:0] — Port H Data Bits
These read/write bits are software-programmable. Data direction of
each port H pin is under the control of the corresponding bit in data
direction register H. Reset has no effect on port G data.
KBD[4:3] — Keyboard Wakeup Pins
The keyboard interrupt enable bits, KBIE[4:3], in the keyboard
interrupt control register (KBICR), enable the port H pins as external
interrupt pins. See Keyboard Module (KBD).
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20.10.2 Data Direction Register H (DDRH)
Data direction register H determines whether each port H pin is an input
or an output. Writing a logic one to a DDRH bit enables the output buffer
for the corresponding port H pin; a logic zero disables the output buffer.
DDRH
$000F
Read:
Bit 7
6
5
4
3
2
0
0
0
0
0
0
1
Bit 0
DDRH1 DDRH0
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 20-23. Data Direction Register H (DDRH)
DDRH[1:0] — Data direction register H bits
These read/write bits control port H data direction. Reset clears
DDRH[1:0], configuring all port H pins as inputs.
1 = Corresponding port H pin configured as output
0 = Corresponding port H pin configured as input
NOTE:
Avoid glitches on port H pins by writing to the port H data register before
changing data direction register H bits from 0 to 1.
Figure 20-24 shows the port H I/O logic.
INTERNAL DATA BUS
READ DDRH ($000E)
WRITE DDRH ($000E)
RESET
DDRHx
WRITE PTH ($000A)
PTHx
PTGx
READ PTH ($000A)
Figure 20-24. Port H I/O Circuit
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When bit DDRHx is a logic one, reading address $000B reads the PTHx
data latch. When bit DDRHx is a logic zero, reading address $000B
reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data. Table 20-9 summarises the operation
of the port H pins.
Table 20-9. Port H Pin Functions
DDRH Bit
PTH Bit
I/O Pin Mode
Accesses to
DDRH
Accesses to PTH
Read/Write
Read
Write
0
X(1)
Input, Hi-Z(2)
DDRH[1:0]
Pin
PTH[1:0](3)
1
X
Output
DDRH[1:0]
PTH[1:0]
PTH[1:0]
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
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Technical Data — MC68HC08AZ60A
Section 21. MSCAN08 Controller (MSCAN08)
21.1 Contents
21.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344
21.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .345
21.4
External Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
21.5 Message Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
21.5.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
21.5.2 Receive Structures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
21.5.3 Transmit Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
21.6
Identifier Acceptance Filter . . . . . . . . . . . . . . . . . . . . . . . . . 352
21.7 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
21.7.1 Interrupt Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . 358
21.7.2 Interrupt Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
21.8
Protocol Violation Protection . . . . . . . . . . . . . . . . . . . . . . .359
21.9 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
21.9.1 MSCAN08 Sleep Mode . . . . . . . . . . . . . . . . . . . . . . . . . . .361
21.9.2 MSCAN08 Soft Reset Mode . . . . . . . . . . . . . . . . . . . . . . . 362
21.9.3 MSCAN08 Power Down Mode . . . . . . . . . . . . . . . . . . . . . 363
21.9.4 CPU Wait Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
21.9.5 Programmable Wakeup Function . . . . . . . . . . . . . . . . . . 364
21.10 Timer Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
21.11 Clock System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
21.12 Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .368
21.13 Programmer’s Model of Message Storage . . . . . . . . . . . . . 368
21.13.1 Message Buffer Outline . . . . . . . . . . . . . . . . . . . . . . . . . . 369
21.13.2 Identifier Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
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21.13.3 Data Length Register (DLR) . . . . . . . . . . . . . . . . . . . . . . 373
21.13.4 Data Segment Registers (DSRn). . . . . . . . . . . . . . . . . . . 373
21.13.5 Transmit Buffer Priority Registers . . . . . . . . . . . . . . . . . 374
21.14 Programmer’s Model of Control Registers . . . . . . . . . . . . 374
21.14.1 MSCAN08 Module Control Register 0 . . . . . . . . . . . . . . 377
21.14.2 MSCAN08 Module Control Register 1 . . . . . . . . . . . . . . 379
21.14.3 MSCAN08 Bus Timing Register 0 . . . . . . . . . . . . . . . . . . 380
21.14.4 MSCAN08 Bus Timing Register 1 . . . . . . . . . . . . . . . . . . 381
21.14.5 MSCAN08 Receiver Flag Register (CRFLG). . . . . . . . . . 383
21.14.6 MSCAN08 Receiver Interrupt Enable Register . . . . . . . 385
21.14.7 MSCAN08 Transmitter Flag Register . . . . . . . . . . . . . . . 387
21.14.8 MSCAN08 Transmitter Control Register . . . . . . . . . . . . 388
21.14.9 MSCAN08 Identifier Acceptance Control Register . . . . 389
21.14.10 MSCAN08 Receive Error Counter . . . . . . . . . . . . . . . . . . 391
21.14.11 MSCAN08 Transmit Error Counter . . . . . . . . . . . . . . . . . 391
21.14.12 MSCAN08 Identifier Acceptance Registers . . . . . . . . . . 392
21.14.13 MSCAN08 Identifier Mask Registers (CIDMR0-3) . . . . . 393
21.2 Introduction
The MSCAN08 is the specific implementation of the scalable controller
area network (MSCAN) concept targeted for the Freescale M68HC08
Microcontroller Family.
The module is a communication controller implementing the CAN 2.0
A/B protocol as defined in the BOSCH specification dated September
1991.
The CAN protocol was primarily, but not exclusively, designed to be
used as a vehicle serial data bus, meeting the specific requirements of
this field: real-time processing, reliable operation in the electromagnetic
interference (EMI) environment of a vehicle, cost-effectiveness and
required bandwidth.
MSCAN08 utilizes an advanced buffer arrangement, resulting in a
predictable real-time behavior, and simplifies the application software.
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21.3 Features
Basic features of the MSCAN08 are:
•
Modular Architecture
•
Implementation of the CAN Protocol — Version 2.0A/B
– Standard and Extended Data Frames.
– 0–8 Bytes Data Length.
– Programmable Bit Rate up to 1 Mbps Depending on the Actual
Bit Timing and the Clock Jitter of the PLL
•
Support for Remote Frames
•
Double-Buffered Receive Storage Scheme
•
Triple-Buffered Transmit Storage Scheme with Internal
Prioritisation Using a “Local Priority” Concept
•
Flexible Maskable Identifier Filter Supports Alternatively One Full
Size Extended Identifier Filter or Two 16-Bit Filters or Four 8-Bit
Filters
•
Programmable Wakeup Functionality with Integrated Low-Pass
Filter
•
Programmable Loop-Back Mode Supports Self-Test Operation
•
Separate Signalling and Interrupt Capabilities for All CAN
Receiver and Transmitter Error States (Warning, Error Passive,
Bus Off)
•
Programmable MSCAN08 Clock Source Either CPU Bus Clock or
Crystal Oscillator Output
•
Programmable Link to On-Chip Timer Interface Module (TIMB) for
Time-Stamping and Network Synchronization
•
Low-Power Sleep Mode
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MSCAN08 Controller (MSCAN08)
21.4 External Pins
The MSCAN08 uses two external pins, one input (RxCAN) and one
output (TxCAN). The TxCAN output pin represents the logic level on the
CAN: 0 is for a dominant state, and 1 is for a recessive state.
A typical CAN system with MSCAN08 is shown in Figure 21-1.
CAN STATION 1
CAN NODE 1
CAN NODE 2
CAN NODE N
MCU
CAN CONTROLLER
(MSCAN08)
TXCAN
RXCAN
TRANSCEIVER
CAN_H
CAN_L
C A N BUS
Figure 21-1. The CAN System
Each CAN station is connected physically to the CAN bus lines through
a transceiver chip. The transceiver is capable of driving the large current
needed for the CAN and has current protection against defective CAN or
defective stations.
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21.5 Message Storage
MSCAN08 facilitates a sophisticated message storage system which
addresses the requirements of a broad range of network applications.
21.5.1 Background
Modern application layer software is built under two fundamental
assumptions:
1. Any CAN node is able to send out a stream of scheduled
messages without releasing the bus between two messages.
Such nodes will arbitrate for the bus right after sending the
previous message and will only release the bus in case of lost
arbitration.
2. The internal message queue within any CAN node is organized as
such that the highest priority message will be sent out first if more
than one message is ready to be sent.
Above behaviour cannot be achieved with a single transmit buffer. That
buffer must be reloaded right after the previous message has been sent.
This loading process lasts a definite amount of time and has to be
completed within the inter-frame sequence (IFS) to be able to send an
uninterrupted stream of messages. Even if this is feasible for limited
CAN bus speeds, it requires that the CPU reacts with short latencies to
the transmit interrupt.
A double buffer scheme would de-couple the re-loading of the transmit
buffers from the actual message being sent and as such reduces the
reactiveness requirements on the CPU. Problems may arise if the
sending of a message would be finished just while the CPU re-loads the
second buffer. In that case, no buffer would then be ready for
transmission and the bus would be released.
At least three transmit buffers are required to meet the first of the above
requirements under all circumstances. The MSCAN08 has three
transmit buffers.
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The second requirement calls for some sort of internal prioritisation
which the MSCAN08 implements with the “local priority” concept
described in Receive Structures on page 348.
21.5.2 Receive Structures
The received messages are stored in a 2-stage input first in first out
(FIFO). The two message buffers are mapped using a Ping Pong
arrangement into a single memory area (see Figure 21-2). While the
background receive buffer (RxBG) is exclusively associated to the
MSCAN08, the foreground receive buffer (RxFG) is addressable by the
CPU08. This scheme simplifies the handler software, because only one
address area is applicable for the receive process.
Both buffers have a size of 13 bytes to store the CAN control bits, the
identifier (standard or extended), and the data content (for details, see
Programmer’s Model of Message Storage on page 368).
The receiver full flag (RXF) in the MSCAN08 receiver flag register
(CRFLG) (see MSCAN08 Receiver Flag Register (CRFLG) on page
383), signals the status of the foreground receive buffer. When the buffer
contains a correctly received message with matching identifier, this flag
is set.
On reception, each message is checked to see if it passes the filter (for
details see Identifier Acceptance Filter on page 352) and in parallel is
written into RxBG. The MSCAN08 copies the content of RxBG into
RxFG(1), sets the RXF flag, and generates a receive interrupt to the
CPU(2). The user’s receive handler has to read the received message
from RxFG and to reset the RXF flag to acknowledge the interrupt and
to release the foreground buffer. A new message which can follow
immediately after the IFS field of the CAN frame, is received into RxBG.
The overwriting of the background buffer is independent of the identifier
filter function.
1. Only if the RXF flag is not set.
2. The receive interrupt will occur only if not masked. A polling scheme can be applied on RXF
also.
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When the MSCAN08 module is transmitting, the MSCAN08 receives its
own messages into the background receive buffer, RxBG. It does NOT
overwrite RxFG, generate a receive interrupt or acknowledge its own
messages on the CAN bus. The exception to this rule is in loop-back
mode (see MSCAN08 Module Control Register 1 on page 379), where
the MSCAN08 treats its own messages exactly like all other incoming
messages. The MSCAN08 receives its own transmitted messages in the
event that it loses arbitration. If arbitration is lost, the MSCAN08 must be
prepared to become receiver.
An overrun condition occurs when both the foreground and the
background receive message buffers are filled with correctly received
messages with accepted identifiers and another message is correctly
received from the bus with an accepted identifier. The latter message will
be discarded and an error interrupt with overrun indication will be
generated if enabled. The MSCAN08 is still able to transmit messages
with both receive message buffers filled, but all incoming messages are
discarded.
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CPU08 Ibus
MSCAN08
RxBG
RxFG
RXF
Tx0
TXE
PRIO
TXE
Tx1
PRIO
TXE
Tx2
PRIO
Figure 21-2. User Model for Message Buffer Organization
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21.5.3 Transmit Structures
The MSCAN08 has a triple transmit buffer scheme to allow multiple
messages to be set up in advance and to achieve an optimized real-time
performance. The three buffers are arranged as shown in Figure 21-2.
All three buffers have a 13-byte data structure similar to the outline of the
receive buffers (see Programmer’s Model of Message Storage on
page 368). An additional transmit buffer priority register (TBPR) contains
an 8-bit “local priority” field (PRIO) (see Transmit Buffer Priority
Registers on page 374).
To transmit a message, the CPU08 has to identify an available transmit
buffer which is indicated by a set transmit buffer empty (TXE) flag in the
MSCAN08 transmitter flag register (CTFLG) (see MSCAN08
Transmitter Flag Register on page 387).
The CPU08 then stores the identifier, the control bits and the data
content into one of the transmit buffers. Finally, the buffer has to be
flagged ready for transmission by clearing the TXE flag.
The MSCAN08 then will schedule the message for transmission and will
signal the successful transmission of the buffer by setting the TXE flag.
A transmit interrupt is generated(1) when TXE is set and can be used to
drive the application software to re-load the buffer.
In case more than one buffer is scheduled for transmission when the
CAN bus becomes available for arbitration, the MSCAN08 uses the local
priority setting of the three buffers for prioritisation. For this purpose,
every transmit buffer has an 8-bit local priority field (PRIO). The
application software sets this field when the message is set up. The local
priority reflects the priority of this particular message relative to the set
of messages being emitted from this node. The lowest binary value of
the PRIO field is defined as the highest priority.
1. The transmit interrupt will occur only if not masked. A polling scheme can be applied on TXE
also.
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The internal scheduling process takes place whenever the MSCAN08
arbitrates for the bus. This is also the case after the occurrence of a
transmission error.
When a high priority message is scheduled by the application software,
it may become necessary to abort a lower priority message being set up
in one of the three transmit buffers. As messages that are already under
transmission cannot be aborted, the user has to request the abort by
setting the corresponding abort request flag (ABTRQ) in the
transmission control register (CTCR). The MSCAN08 will then grant the
request, if possible, by setting the corresponding abort request
acknowledge (ABTAK) and the TXE flag in order to release the buffer
and by generating a transmit interrupt. The transmit interrupt handler
software can tell from the setting of the ABTAK flag whether the
message was actually aborted (ABTAK = 1) or sent (ABTAK = 0).
21.6 Identifier Acceptance Filter
The Identifier Acceptance Registers (CIDAR0-3) define the acceptance
patterns of the standard or extended identifier (ID10-ID0 or ID28-ID0).
Any of these bits can be marked ‘don’t care’ in the Identifier Mask
Registers (CIDMR0-3).
A filter hit is indicated to the application on software by a set RXF
(Receive Buffer Full Flag, see MSCAN08 Receiver Flag Register
(CRFLG) on page 383) and two bits in the Identifier Acceptance Control
Register (see MSCAN08 Identifier Acceptance Control Register on
page 389). These Identifier Hit Flags (IDHIT1-0) clearly identify the filter
section that caused the acceptance. They simplify the application
software’s task to identify the cause of the receiver interrupt. In case that
more than one hit occurs (two or more filters match) the lower hit has
priority.
A very flexible programmable generic identifier acceptance filter has
been introduced to reduce the CPU interrupt loading. The filter is
programmable to operate in four different modes:
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•
Single identifier acceptance filter, each to be applied to a) the full
29 bits of the extended identifier and to the following bits of the
CAN frame: RTR, IDE, SRR or b) the 11 bits of the standard
identifier plus the RTR and IDE bits of CAN 2.0A/B messages.
This mode implements a single filter for a full length CAN 2.0B
compliant extended identifier. Figure 21-3 shows how the 32-bit
filter bank (CIDAR0-3, CIDMR0-3) produces a filter 0 hit.
•
Two identifier acceptance filters, each to be applied to a) the 14
most significant bits of the extended identifier plus the SRR and
the IDE bits of CAN2.0B messages, or b) the 11 bits of the
identifier plus the RTR and IDE bits of CAN 2.0A/B messages.
Figure 21-4 shows how the 32-bit filter bank (CIDAR0-3,
CIDMR0-3) produces filter 0 and 1 hits.
•
Four identifier acceptance filters, each to be applied to the first
eight bits of the identifier. This mode implements four independent
filters for the first eight bits of a CAN 2.0A/B compliant standard
identifier. Figure 21-5 shows how the 32-bit filter bank (CIDAR03, CIDMR0-3) produces filter 0 to 3 hits.
•
Closed filter. No CAN message will be copied into the foreground
buffer RxFG, and the RXF flag will never be set.
ID28
IDR0
ID21 ID20
IDR1
ID15 ID14
ID10
IDR0
ID3 ID2
IDR1
AM7
CIDMR0
AM0 AM7
CIDMR1
AM0 AM7
CIDMR2
AC7
CIDAR0
AC0 AC7
CIDAR1
AC0 AC7
CIDAR2
IDE
ID10
IDR2
ID7 ID6
IDR3
RTR
IDR2
ID3 ID10
IDR3
ID3
AM0 AM7
CIDMR3
AM0
AC0 AC7
CIDAR3
AC0
ID Accepted (Filter 0 Hit)
Figure 21-3. Single 32-Bit Maskable Identifier Acceptance Filter
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ID28
IDR0
ID21 ID20
IDR1
ID10
IDR0
ID3 ID2
IDR1
ID15 ID14
AM7
CIDMR0
AM0 AM7
CIDMR1
AM0
AC7
CIDAR0
AC0 AC7
CIDAR1
AC0
IDE
ID10
IDR2
ID7 ID6
IDR3
RTR
IDR2
ID3 ID10
IDR3
ID3
ID ACCEPTED (FILTER 0 HIT)
AM7
CIDMR2
AM0 AM7
CIDMR3
AM0
AC7
CIDAR2
AC0 AC7
CIDAR3
AC0
ID ACCEPTED (FILTER 1 HIT)
Figure 21-4. Dual 16-Bit Maskable Acceptance Filters
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.
ID28
IDR0
ID21 ID20
IDR1
ID10
IDR0
ID3 ID2
IDR1
AM7
CIDMR0
AM0
AC7
CIDAR0
AC0
ID15 ID14
IDE
ID10
IDR2
ID7 ID6
IDR3
RTR
IDR2
ID3 ID10
IDR3
ID3
ID ACCEPTED (FILTER 0 HIT)
AM7
CIDMR1
AM0
AC7
CIDAR1
AC0
ID ACCEPTED (FILTER 1 HIT)
AM7
CIDMR2
AM0
AC7
CIDAR2
AC0
ID ACCEPTED (FILTER 2 HIT)
AM7
CIDMR3
AM0
AC7
CIDAR3
AC0
ID ACCEPTED (FILTER 3 HIT)
Figure 21-5. Quadruple 8-Bit Maskable Acceptance Filters
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21.6.1 MSCAN Extended ID Rejected if Stuff Bit Between ID16 and ID15
For 32-bit and 16-bit identifier acceptance modes, an extended ID CAN
frame with a stuff bit between ID16 and ID15 can be erroneously
rejected, depending on IDAR0, IDAR1, and IDMR1.
Extended IDs (ID28-ID0) which generate a stuff bit between ID16 and
ID15:
IDAR0
IDAR1
IDAR2
IDAR3
********
***1111x
xxxxxxxx
xxxxxxxx
where x = 0 or 1 (don't care)
* = pattern for ID28 to ID18 (see following).
Affected extended IDs (ID28 - ID18) patterns:
a)
xxxxxxxxx01
exceptions: 00000000001
01111100001
xxxx1000001 except
11111000001
b)
xxxxx100000
exception:
01111100000
c)
xxxx0111111
exception:
00000111111
d)
x0111110000
e)
10000000000
f)
11111111111
g)
10000011111
When an affected ID is received, an incorrect value is compared to the
2nd byte of the filter (IDAR1 and IDAR5, plus IDAR3 and IDAR7 in 16bit mode). This incorrect value is the shift register contents before ID15
is shifted in (i.e. right shifted by 1).
21.6.1.1 Work- around
If the problematic IDs cannot be avoided, the workaround is to mask
certain bits with IDMR1 (and IDMR5, plus IDMR3 and IDMR7 in 16-bit
mode).
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Example 1: to receive the message IDs
xxxx xxxx x011 111x xxxx xxxx xxxx xxxx
IDMR1 etc. must be 111x xxx1, i.e. ID20,19,18,15 must be masked.
Example 2: to receive the message IDs
xxxx 0111 1111 111x xxxx xxxx xxxx xxxx
IDMR1 etc. must be 1xxx xxx1, i.e. ID20 and ID15 must be masked.
In general, using IDMR1 etc. 1111 xxx1, i.e. masking
ID20,19,18,SRR,15, hides the problem.
21.7 Interrupts
The MSCAN08 supports four interrupt vectors mapped onto eleven
different interrupt sources, any of which can be individually masked (for
details see MSCAN08 Receiver Flag Register (CRFLG) on page 383,
to MSCAN08 Transmitter Control Register on page 388).
•
Transmit Interrupt: At least one of the three transmit buffers is
empty (not scheduled) and can be loaded to schedule a message
for transmission. The TXE flags of the empty message buffers are
set.
•
Receive Interrupt: A message has been received successfully and
loaded into the foreground receive buffer. This interrupt will be
emitted immediately after receiving the EOF symbol. The RXF flag
is set.
•
Wakeup Interrupt: An activity on the CAN bus occurred during
MSCAN08 internal sleep mode or power-down mode (provided
SLPAK = WUPIE = 1).
•
Error Interrupt: An overrun, error, or warning condition occurred.
The receiver flag register (CRFLG) will indicate one of the
following conditions:
– Overrun: An overrun condition as described in Receive
Structures on page 348, has occurred.
– Receiver Warning: The receive error counter has reached the
CPU Warning limit of 96.
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– Transmitter Warning: The transmit error counter has reached
the CPU Warning limit of 96.
– Receiver Error Passive: The receive error counter has
exceeded the error passive limit of 127 and MSCAN08 has
gone to error passive state.
– Transmitter Error Passive: The transmit error counter has
exceeded the error passive limit of 127 and MSCAN08 has
gone to error passive state.
– Bus Off: The transmit error counter has exceeded 255 and
MSCAN08 has gone to bus off state.
21.7.1 Interrupt Acknowledge
Interrupts are directly associated with one or more status flags in either
the MSCAN08 receiver flag register (CRFLG) or the MSCAN08
transmitter flag register (CTFLG). Interrupts are pending as long as one
of the corresponding flags is set. The flags in the above registers must
be reset within the interrupt handler in order to handshake the interrupt.
The flags are reset through writing a ‘1’ to the corresponding bit position.
A flag cannot be cleared if the respective condition still prevails.
NOTE:
Bit manipulation instructions (BSET) shall not be used to clear interrupt
flags.
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21.7.2 Interrupt Vectors
The MSCAN08 supports four interrupt vectors as shown in Table 21-1.
The vector addresses and the relative interrupt priority are defined in
Table 2-1.
Table 21-1. MSCAN08 Interrupt Vector Addresses
Function
Source
Local
Mask
Wakeup
WUPIF
WUPIE
RWRNIF
RWRNIE
TWRNIF
TWRNIE
RERRIF
RERRIE
TERRIF
TERRIE
BOFFIF
BOFFIE
OVRIF
OVRIE
Error
Interrupts
Receive
Transmit
RXF
RXFIE
TXE0
TXEIE0
TXE1
TXEIE1
TXE2
TXEIE2
Global
Mask
I Bit
21.8 Protocol Violation Protection
The MSCAN08 will protect the user from accidentally violating the CAN
protocol through programming errors. The protection logic implements
the following features:
•
The receive and transmit error counters cannot be written or
otherwise manipulated.
•
All registers which control the configuration of the MSCAN08 can
not be modified while the MSCAN08 is on-line. The SFTRES bit in
the MSCAN08 module control register (see MSCAN08 Module
Control Register 0 on page 377) serves as a lock to protect the
following registers:
– MSCAN08 module control register 1 (CMCR1)
– MSCAN08 bus timing register 0 and 1 (CBTR0 and CBTR1)
– MSCAN08 identifier acceptance control register (CIDAC)
– MSCAN08 identifier acceptance registers (CIDAR0–3)
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– MSCAN08 identifier mask registers (CIDMR0–3)
•
The TxCAN pin is forced to recessive when the MSCAN08 is in
any of the Low Power Modes.
21.9 Low Power Modes
In addition to normal mode, the MSCAN08 has three modes with
reduced power consumption: Sleep, Soft Reset and Power Down
modes. In Sleep and Soft Reset mode, power consumption is reduced
by stopping all clocks except those to access the registers. In Power
Down mode, all clocks are stopped and no power is consumed.
The WAIT and STOP instructions put the MCU in low power
consumption stand-by modes. summarizes the combinations of
MSCAN08 and CPU modes. A particular combination of modes is
entered for the given settings of the bits SLPAK and SFTRES. For all
modes, an MSCAN wake-up interrupt can occur only if
SLPAK=WUPIE=1.
.
Table 21-2 MSCAN08 vs CPU Operating Modes
CPU Mode
MSCAN Mode
STOP
Power Down
WAIT or RUN
SLPAK = X(1)
SFTRES = X
Sleep
SLPAK = 1
SFTRES = 0
Soft Reset
SLPAK = 0
SFTRES = 1
Normal
SLPAK = 0
SFTRES = 0
1. ‘X’ means don’t care.
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21.9.1 MSCAN08 Sleep Mode
The CPU can request the MSCAN08 to enter the low-power mode by
asserting the SLPRQ bit in the module configuration register (see Figure
21-6). The time when the MSCAN08 enters Sleep mode depends on its
activity:
NOTE:
•
if it is transmitting, it continues to transmit until there is no more
message to be transmitted, and then goes into Sleep mode
•
if it is receiving, it waits for the end of this message and then goes
into Sleep mode
•
if it is neither transmitting or receiving, it will immediately go into
Sleep mode
The application software must avoid setting up a transmission (by
clearing or more TXE flags) and immediately request Sleep mode (by
setting SLPRQ). It then depends on the exact sequence of operations
whether MSCAN08 starts transmitting or goes into Sleep mode directly.
During Sleep mode, the SLPAK flag is set. The application software
should use SLPAK as a handshake indication for the request (SLPRQ)
to go into Sleep mode. When in Sleep mode, the MSCAN08 stops its
internal clocks. However, clocks to allow register accesses still run. If the
MSCAN08 is in buss-off state, it stops counting the 128*11 consecutive
recessive bits due to the stopped clocks. The TxCAN pin stays in
recessive state. If RXF=1, the message can be read and RXF can be
cleared. Copying of RxGB into RxFG doesn’t take place while in Sleep
mode. It is possible to access the transmit buffers and to clear the TXE
flags. No message abort takes place while in Sleep mode.
The MSCAN08 leaves Sleep mode (wake-up) when:
•
bus activity occurs or
•
the MCU clears the SLPRQ bit or
•
the MCU sets the SFTRES bit
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MSCAN08 Running
SLPRQ = 0
SLPAK = 0
MCU
MCU
or MSCAN08
MSCAN08 Sleeping
Sleep Request
SLPRQ = 1
SLPAK = 1
SLPRQ = 1
SLPAK = 0
MSCAN08
Figure 21-6. Sleep Request/Acknowledge Cycle
NOTE:
The MCU cannot clear the SLPRQ bit before the MSCAN08 is in Sleep
mode (SLPAK=1).
After wake-up, the MSCAN08 waits for 11 consecutive recessive bits to
synchronize to the bus. As a consequence, if the MSCAN08 is wokenup by a CAN frame, this frame is not received. The receive message
buffers (RxFG and RxBG) contain messages if they were received
before Sleep mode was entered. All pending actions are executed upon
wake-up: copying of RxBG into RxFG, message aborts and message
transmissions. If the MSCAN08 is still in bus-off state after Sleep mode
was left, it continues counting the 128*11 consecutive recessive bits.
21.9.2 MSCAN08 Soft Reset Mode
In Soft Reset mode, the MSCAN08 is stopped. Registers can still be
accessed. This mode is used to initialize the module configuration, bit
timing and the CAN message filter. See MSCAN08 Module Control
Register 0 on page 377 for a complete description of the Soft Reset
mode.
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When setting the SFTRES bit, the MSCAN08 immediately stops all
ongoing transmissions and receptions, potentially causing CAN protocol
violations.
NOTE:
The user is responsible to take care that the MSCAN08 is not active
when Soft Reset mode is entered. The recommended procedure is to
bring the MSCAN08 into Sleep mode before the SFTRES bit is set.
21.9.3 MSCAN08 Power Down Mode
The MSCAN08 is in Power Down mode when the CPU is in Stop mode.
When entering the Power Down mode, the MSCAN08 immediately stops
all ongoing transmissions and receptions, potentially causing CAN
protocol violations.
NOTE:
The user is responsible to take care that the MSCAN08 is not active
when Power Down mode is entered. The recommended procedure is to
bring the MSCAN08 into Sleep mode before the STOP instruction is
executed.
To protect the CAN bus system from fatal consequences of violations to
the above rule, the MSCAN08 drives the TxCAN pin into recessive state.
In Power Down mode, no registers can be accessed.
MSCAN08 bus activity can wake the MCU from CPU Stop/MSCAN08
power-down mode. However, until the oscillator starts up and
synchronisation is achieved the MSCAN08 will not respond to incoming
data.
21.9.4 CPU Wait Mode
The MSCAN08 module remains active during CPU wait mode. The
MSCAN08 will stay synchronized to the CAN bus and generates
transmit, receive, and error interrupts to the CPU, if enabled. Any such
interrupt will bring the MCU out of wait mode.
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21.9.5 Programmable Wakeup Function
The MSCAN08 can be programmed to apply a low-pass filter function to
the RxCAN input line while in internal sleep mode (see information on
control bit WUPM in MSCAN08 Module Control Register 1 on page
379). This feature can be used to protect the MSCAN08 from wake-up
due to short glitches on the CAN bus lines. Such glitches can result from
electromagnetic inference within noisy environments.
21.10 Timer Link
The MSCAN08 will generate a timer signal whenever a valid frame has
been received. Because the CAN specification defines a frame to be
valid if no errors occurred before the EOF field has been transmitted
successfully, the timer signal will be generated right after the EOF. A
pulse of one bit time is generated. As the MSCAN08 receiver engine also
receives the frames being sent by itself, a timer signal also will be
generated after a successful transmission.
The previously described timer signal can be routed into the on-chip
Timer Interface Module B (TIMB).This signal is connected to the
Channel 0 input under the control of the timer link enable (TLNKEN) bit
in the CMCR0.
After the TIMB module has been programmed to capture rising edge
events, it can be used under software control to generate 16-bit time
stamps which can be stored with the received message.
21.11 Clock System
Figure 21-7 shows the structure of the MSCAN08 clock generation
circuitry and its interaction with the clock generation module (CGM).
With this flexible clocking scheme the MSCAN08 is able to handle CAN
bus rates ranging from 10 kbps up to 1 Mbps.
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CGMXCLK
÷2
OSC
CGMOUT
(TO SIM)
BCS
PLL
÷2
CGM
MSCAN08
(2 * BUS FREQ.)
÷2
MSCANCLK
PRESCALER
CLKSRC
(1 .. 64)
Figure 21-7. Clocking Scheme
The clock source bit (CLKSRC) in the MSCAN08 module control register
(CMCR1) (see MSCAN08 Module Control Register 0 on page 377)
defines whether the MSCAN08 is connected to the output of the crystal
oscillator or to the PLL output.
The clock source has to be chosen such that the tight oscillator tolerance
requirements (up to 0.4%) of the CAN protocol are met.
NOTE:
If the system clock is generated from a PLL, it is recommended to select
the crystal clock source rather than the system clock source due to jitter
considerations, especially at faster CAN bus rates.
A programmable prescaler is used to generate out of the MSCAN08
clock the time quanta (Tq) clock. A time quantum is the atomic unit of
time handled by the MSCAN08.
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fTq =
fMSCANCLK
Presc value
A bit time is subdivided into three segments(1)(see Figure 21-8).
•
SYNC_SEG: This segment has a fixed length of one time
quantum. Signal edges are expected to happen within this section.
•
Time segment 1: This segment includes the PROP_SEG and the
PHASE_SEG1 of the CAN standard. It can be programmed by
setting the parameter TSEG1 to consist of 4 to 16 time quanta.
•
Time segment 2: This segment represents PHASE_SEG2 of the
CAN standard. It can be programmed by setting the TSEG2
parameter to be 2 to 8 time quanta long.
Bit rate=
fTq
No. of time quanta
The synchronization jump width (SJW) can be programmed in a range
of 1 to 4 time quanta by setting the SJW parameter.
The above parameters can be set by programming the bus timing
registers, CBTR0–CBTR1, see MSCAN08 Bus Timing Register 0 on
page 380 and MSCAN08 Bus Timing Register 1 on page 381).
NOTE:
It is the user’s responsibility to make sure that the bit timing settings are
in compliance with the CAN standard,
Table 21-8 gives an overview on the CAN conforming segment settings
and the related parameter values.
1. For further explanation of the underlying concepts please refer to ISO/DIS 11 519-1, Section
10.3.
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NRZ SIGNAL
SYNC
_SEG
TIME SEGMENT 1
(PROP_SEG + PHASE_SEG1)
TIME SEG. 2
(PHASE_SEG2)
1
4 ... 16
2 ... 8
8... 25 TIME QUANTA
= 1 BIT TIME
SAMPLE POINT
(SINGLE OR TRIPLE SAMPLING)
Figure 21-8. Segments Within the Bit Time
Table 21-3. Time segment syntax
SYNC_SEG
System expects transitions to occur on the bus
during this period.
Transmit point
A node in transmit mode will transfer a new
value to the CAN bus at this point.
Sample point
A node in receive mode will sample the bus at
this point. If the three samples per bit option is
selected then this point marks the position of
the third sample.
Time
Segment 1
TSEG1
Time
Segment 2
TSEG2
Synchron.
Jump Width
SJW
5 .. 10
4 .. 9
2
1
1 .. 2
0 .. 1
4 .. 11
3 .. 10
3
2
1 .. 3
0 .. 2
5 .. 12
4 .. 11
4
3
1 .. 4
0 .. 3
6 .. 13
5 .. 12
5
4
1 .. 4
0 .. 3
7 .. 14
6 .. 13
6
5
1 .. 4
0 .. 3
8 .. 15
7 .. 14
7
6
1 .. 4
0 .. 3
9 .. 16
8 .. 15
8
7
1 .. 4
0 .. 3
Table 21-4. CAN Standard Compliant Bit Time Segment Settings
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21.12 Memory Map
The MSCAN08 occupies 128 bytes in the CPU08 memory space, as
shown in Figure 21-9.
$0500
$0508
$0509
$050D
$050E
$050F
$0510
$0517
$0518
$053F
$0540
$054F
$0550
$055F
$0560
$056F
$0570
$057F
CONTROL REGISTERS
9 BYTES
RESERVED
5 BYTES
ERROR COUNTERS
2 BYTES
IDENTIFIER FILTER
8 BYTES
RESERVED
40 BYTES
RECEIVE BUFFER
TRANSMIT BUFFER 0
TRANSMIT BUFFER 1
TRANSMIT BUFFER 2
Figure 21-9. MSCAN08 Memory Map
21.13 Programmer’s Model of Message Storage
This section details the organization of the receive and transmit
message buffers and the associated control registers. For reasons of
programmer interface simplification, the receive and transmit message
buffers have the same outline. Each message buffer allocates 16 bytes
in the memory map containing a 13-byte data structure. An additional
transmit buffer priority register (TBPR) is defined for the transmit buffers.
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Addr(1)
Register Name
$05b0
IDENTIFIER REGISTER 0
$05b1
IDENTIFIER REGISTER 1
$05b2
IDENTIFIER REGISTER 2
$05b3
IDENTIFIER REGISTER 3
$05b4
DATA SEGMENT REGISTER 0
$05b5
DATA SEGMENT REGISTER 1
$05b6
DATA SEGMENT REGISTER 2
$05b7
DATA SEGMENT REGISTER 3
$05b8
DATA SEGMENT REGISTER 4
$05b9
DATA SEGMENT REGISTER 5
$05bA
DATA SEGMENT REGISTER 6
$05bB
DATA SEGMENT REGISTER 7
$05bC
DATA LENGTH REGISTER
$05bD
TRANSMIT BUFFER PRIORITY
REGISTER(2)
$05bE
UNUSED
$05bF
UNUSED
1. Where b equals the following:
b=4 for Receive Buffer
b=5 for Transmit Buffer 0
b=6 for Transmit Buffer 1
b=7 for Transmit Buffer 2
2. Not applicable for receive buffers
Figure 21-10. Message Buffer Organization
21.13.1 Message Buffer Outline
Figure 21-11 shows the common 13-byte data structure of receive and
transmit buffers for extended identifiers. The mapping of standard
identifiers into the IDR registers is shown in Figure 21-12. All bits of the
13-byte data structure are undefined out of reset.
NOTE:
The foreground receive buffer can be read anytime but cannot be
written. The transmit buffers can be read or written anytime.
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21.13.2 Identifier Registers
The identifiers consist of either 11 bits (ID10–ID0) for the standard, or 29
bits (ID28–ID0) for the extended format. ID10/28 is the most significant
bit and is transmitted first on the bus during the arbitration procedure.
The priority of an identifier is defined to be highest for the smallest binary
number.
SRR — Substitute Remote Request
This fixed recessive bit is used only in extended format. It must be set
to 1 by the user for transmission buffers and will be stored as received
on the CAN bus for receive buffers.
Addr
Register
$05b0
IDR0
$05b1
IDR1
$05b2
IDR2
$05b3
IDR3
$05b4
DSR0
$05b5
DSR1
Bit 7
6
5
4
3
2
1
Bit 0
ID28
ID27
ID26
ID25
ID24
ID23
ID22
ID21
ID20
ID19
ID18
SRR (=1)
IDE (=1)
ID17
ID16
ID15
ID14
ID13
ID12
ID11
ID10
ID9
ID8
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
RTR
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Figure 21-11. Receive/Transmit Message Buffer Extended Identifier (IDRn) (Sheet 1 of 2)
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Addr
Register
$05b6
DSR2
$05b7
DSR3
$05b8
DSR4
$05b9
DSR5
$05bA
DSR6
$05bB
DSR7
$05bC
DLR
Bit 7
6
5
4
3
2
1
Bit 0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DLC3
DLC2
DLC1
DLC0
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
= Unimplemented
Figure 21-11. Receive/Transmit Message Buffer Extended Identifier (IDRn) (Sheet 2 of 2)
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Addr
Register
$05b0
IDR0
Bit 7
6
5
4
3
2
1
Bit 0
ID10
ID9
ID8
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
RTR
IDE(=0)
Read:
Write:
Read:
$05b1
IDR1
Write:
Read:
$05b2
IDR2
Write:
Read:
$05b3
IDR3
Write:
= Unimplemented
Figure 21-12. Standard Identifier Mapping
IDE — ID Extended
This flag indicates whether the extended or standard identifier format
is applied in this buffer. In case of a receive buffer, the flag is set as
being received and indicates to the CPU how to process the buffer
identifier registers. In case of a transmit buffer, the flag indicates to the
MSCAN08 what type of identifier to send.
1 = Extended format, 29 bits
0 = Standard format, 11 bits
RTR — Remote Transmission Request
This flag reflects the status of the remote transmission request bit in
the CAN frame. In case of a receive buffer, it indicates the status of
the received frame and supports the transmission of an answering
frame in software. In case of a transmit buffer, this flag defines the
setting of the RTR bit to be sent.
1 = Remote frame
0 = Data frame
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21.13.3 Data Length Register (DLR)
This register keeps the data length field of the CAN frame.
DLC3–DLC0 — Data Length Code Bits
The data length code contains the number of bytes (data byte count)
of the respective message. At transmission of a remote frame, the
data length code is transmitted as programmed while the number of
transmitted bytes is always 0. The data byte count ranges from 0 to 8
for a data frame. Table 21-5 shows the effect of setting the DLC bits.
Table 21-5. Data Length Codes
Data Length Code
DLC3
DLC2
DLC1
DLC0
Data
Byte
Count
0
0
0
0
0
0
0
0
1
1
0
0
1
0
2
0
0
1
1
3
0
1
0
0
4
0
1
0
1
5
0
1
1
0
6
0
1
1
1
7
1
0
0
0
8
21.13.4 Data Segment Registers (DSRn)
The eight data segment registers contain the data to be transmitted or
received. The number of bytes to be transmitted or being received is
determined by the data length code in the corresponding DLR.
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21.13.5 Transmit Buffer Priority Registers
Address:
Read:
Write:
Reset:
$05bD
Bit 7
6
5
4
3
2
1
Bit 0
PRIO7
PRIO6
PRIO5
PRIO4
PRIO3
PRIO2
PRIO1
PRIO0
u
u
u
u
u
u
u
u
Figure 21-13. Transmit Buffer Priority Register (TBPR)
PRIO7–PRIO0 — Local Priority
This field defines the local priority of the associated message buffer.
The local priority is used for the internal prioritisation process of the
MSCAN08 and is defined to be highest for the smallest binary
number. The MSCAN08 implements the following internal
prioritisation mechanism:
•
All transmission buffers with a cleared TXE flag participate in the
prioritisation right before the SOF is sent.
•
The transmission buffer with the lowest local priority field wins the
prioritisation.
•
In case more than one buffer has the same lowest priority, the
message buffer with the lower index number wins.
21.14 Programmer’s Model of Control Registers
The programmer’s model has been laid out for maximum simplicity and
efficiency. Figure 21-14 gives an overview on the control register block
of the MSCAN08.
Technical Data
374
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
Addr
Register
$0500
CMCR0
$0501
CMCR1
$0502
CBTR0
$0503
CBTR1
$0504
CRFLG
$0505
CRIER
$0506
CTFLG
$0507
CTCR
$0508
CIDAC
$0509
Reserved
Read:
Bit 7
6
5
4
1
Bit 0
0
0
0
SYNCH
SLPRQ
SFTRES
0
0
0
0
0
LOOPB
WUPM
CLKSRC
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
SAMP
TSEG22
TSEG21
TSEG20
TSEG13
TSEG12
TSEG11
TSEG10
WUPIF
RWRNIF
TWRNIF
RERRIF
TERRIF
BOFFIF
OVRIF
RXF
WUPIE
RWRNIE
TWRNIE
RERRIE
TERRIE
BOFFIE
OVRIE
RXFIE
0
ABTAK2
ABTAK1
ABTAK0
0
TXE2
TXE1
TXE0
ABTRQ2
ABTRQ1
ABTRQ0
TXEIE2
TXEIE1
TXEIE0
IDAM1
IDAM0
0
0
IDHIT1
IDHIT0
R
R
R
R
R
R
R
= Reserved
Write:
Read:
3
TLNKEN
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
0
Write:
Read:
0
0
R
R
Write:
Read:
Write:
= Unimplemented
0
2
SLPAK
Figure 21-14. MSCAN08 Control Register Structure
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
375
MSCAN08 Controller (MSCAN08)
Addr
Register
$050E
CRXERR
$050F
CTXERR
$0510
CIDAR0
$0511
CIDAR1
$0512
CIDAR2
$0513
CIDAR3
$0514
CIDMR0
$0515
CIDMR1
$0516
CIDMR2
$0517
CIDMR3
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
RXERR7
RXERR6
RXERR5
RXERR4
RXERR3
RXERR2
RXERR1
RXERR0
TXERR7
TXERR6
TXERR5
TXERR4
TXERR3
TXERR2
TXERR1
TXERR0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
Figure 21-14. MSCAN08 Control Register Structure (Continued)
Technical Data
376
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
21.14.1 MSCAN08 Module Control Register 0
Address:
Read:
$0500
Bit 7
6
5
4
0
0
0
SYNCH
0
0
0
0
Write:
Reset:
3
TLNKEN
0
2
SLPAK
0
1
Bit 0
SLPRQ
SFTRES
0
1
= Unimplemented
Figure 21-15. Module Control Register 0 (CMCR0)
SYNCH — Synchronized Status
This bit indicates whether the MSCAN08 is synchronized to the CAN
bus and as such can participate in the communication process.
1 = MSCAN08 synchronized to the CAN bus
0 = MSCAN08 not synchronized to the CAN bus
TLNKEN — Timer Enable
This flag is used to establish a link between the MSCAN08 and the
on-chip timer (see Timer Link on page 364).
1 = The MSCAN08 timer signal output is connected to the Timer
Interface Module B Channel 0.
0 = The port is connected to the timer input.
SLPAK — Sleep Mode Acknowledge
This flag indicates whether the MSCAN08 is in module internal sleep
mode. It shall be used as a handshake for the sleep mode request
(see MSCAN08 Sleep Mode on page 361). If the MSCAN08 detects
bus activity while in Sleep mode, it clears the flag.
1 = Sleep – MSCAN08 in internal sleep mode
0 = Wakeup – MSCAN08 is not in Sleep mode
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
377
MSCAN08 Controller (MSCAN08)
SLPRQ — Sleep Request, Go to Internal Sleep Mode
This flag requests the MSCAN08 to go into an internal power-saving
mode (see MSCAN08 Sleep Mode on page 361).
1 = Sleep — The MSCAN08 will go into internal sleep mode.
0 = Wakeup — The MSCAN08 will function normally.
SFTRES — Soft Reset
When this bit is set by the CPU, the MSCAN08 immediately enters the
soft reset state. Any ongoing transmission or reception is aborted and
synchronization to the bus is lost.
The following registers enter and stay in their hard reset state:
CMCR0, CRFLG, CRIER, CTFLG, and CTCR.
The registers CMCR1, CBTR0, CBTR1, CIDAC, CIDAR0–3, and
CIDMR0–3 can only be written by the CPU when the MSCAN08 is in
soft reset state. The values of the error counters are not affected by
soft reset.
When this bit is cleared by the CPU, the MSCAN08 tries to
synchronize to the CAN bus. If the MSCAN08 is not in bus-off state,
it will be synchronized after 11 recessive bits on the bus; if the
MSCAN08 is in bus-off state, it continues to wait for 128 occurrences
of 11 recessive bits.
Clearing SFTRES and writing to other bits in CMCR0 must be in
separate instructions.
1 = MSCAN08 in soft reset state
0 = Normal operation
Technical Data
378
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
21.14.2 MSCAN08 Module Control Register 1
Address:
Read:
$0501
Bit 7
6
5
4
3
0
0
0
0
0
0
0
0
0
0
Write:
Reset:
2
1
Bit 0
LOOPB
WUPM
CLKSRC
0
0
0
= Unimplemented
Figure 21-16. Module Control Register (CMCR1)
LOOPB — Loop Back Self-Test Mode
When this bit is set, the MSCAN08 performs an internal loop back
which can be used for self-test operation: the bit stream output of the
transmitter is fed back to the receiver internally. The RxCAN input pin
is ignored and the TxCAN output goes to the recessive state (logic
‘1’). The MSCAN08 behaves as it does normally when transmitting
and treats its own transmitted message as a message received from
a remote node. In this state the MSCAN08 ignores the bit sent during
the ACK slot of the CAN frame Acknowledge field to insure proper
reception of its own message. Both transmit and receive interrupt are
generated.
1 = Activate loop back self-test mode
0 = Normal operation
WUPM — Wakeup Mode
This flag defines whether the integrated low-pass filter is applied to
protect the MSCAN08 from spurious wakeups (see Programmable
Wakeup Function on page 364).
1 = MSCAN08 will wake up the CPU only in cases of a dominant
pulse on the bus which has a length of at least twup.
0 = MSCAN08 will wake up the CPU after any recessive to
dominant edge on the CAN bus.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
379
MSCAN08 Controller (MSCAN08)
CLKSRC — Clock Source
This flag defines which clock source the MSCAN08 module is driven
from (see Clock System on page 364).
1 = The MSCAN08 clock source is CGMOUT (see Figure 21-7).
0 = The MSCAN08 clock source is CGMXCLK/2 (see Figure 21-7).
NOTE:
The CMCR1 register can be written only if the SFTRES bit in the
MSCAN08 module control register is set
21.14.3 MSCAN08 Bus Timing Register 0
Address:
Read:
Write:
Reset:
$0502
Bit 7
6
5
4
3
2
1
Bit 0
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
0
0
0
0
0
0
0
0
Figure 21-17. Bus Timing Register 0 (CBTR0)
SJW1 and SJW0 — Synchronization Jump Width
The synchronization jump width (SJW) defines the maximum number
of time quanta (Tq) clock cycles by which a bit may be shortened, or
lengthened, to achieve resynchronization on data transitions on the
bus (see Table 21-6).
Table 21-6. Synchronization Jump Width
SJW1
SJW0
Synchronization Jump Width
0
0
1 Tq cycle
0
1
2 Tq cycle
1
0
3 Tq cycle
1
1
4 Tq cycle
Technical Data
380
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
BRP5–BRP0 — Baud Rate Prescaler
These bits determine the time quanta (Tq) clock, which is used to build
up the individual bit timing, according toTable 21-7.
Table 21-7. Baud Rate Prescaler
NOTE:
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
Prescaler Value (P)
0
0
0
0
0
0
1
0
0
0
0
0
1
2
0
0
0
0
1
0
3
0
0
0
0
1
1
4
:
:
:
:
:
:
:
:
:
:
:
:
:
:
1
1
1
1
1
1
64
The CBTR0 register can be written only if the SFTRES bit in the
MSCAN08 module control register is set.
21.14.4 MSCAN08 Bus Timing Register 1
Address:
Read:
Write:
Reset:
$0503
Bit 7
6
5
4
3
2
1
Bit 0
SAMP
TSEG22
TSEG21
TSEG20
TSEG13
TSEG12
TSEG11
TSEG10
0
0
0
0
0
0
0
0
Figure 21-18. Bus Timing Register 1 (CBTR1)
SAMP — Sampling
This bit determines the number of serial bus samples to be taken per
bit time. If set, three samples per bit are taken, the regular one
(sample point) and two preceding samples, using a majority rule. For
higher bit rates, SAMP should be cleared, which means that only one
sample will be taken per bit.
1 = Three samples per bit(1)
0 = One sample per bit
1. In this case PHASE_SEG1 must be at least 2 time quanta.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
381
MSCAN08 Controller (MSCAN08)
TSEG22–TSEG10 — Time Segment
Time segments within the bit time fix the number of clock cycles per
bit time and the location of the sample point.
Time segment 1 (TSEG1) and time segment 2 (TSEG2) are
programmable as shown in Table 21-9.
Table 21-8. Time Segment Values
TSEG13
TSEG12
TSEG11
TSEG10
Time
Segment 1
TSEG22
TSEG21
TSEG20
Time
Segment 2
0
0
0
0
1 Tq Cycle(1)
0
0
0
1 Tq Cycle(1)
0
0
0
1
2 Tq Cycles(1)
0
0
1
2 Tq Cycles
0
0
1
0
3Tq Cycles(1)
.
.
.
.
0
0
1
1
4 Tq Cycles
.
.
.
.
.
.
.
.
.
.
.
.
.
.
1
1
1
8Tq Cycles
1
1
1
1
16 Tq Cycles
1. This setting is not valid. Please refer to Table 21-4 for valid settings.
The bit time is determined by the oscillator frequency, the baud rate
prescaler, and the number of time quanta (Tq) clock cycles per bit as
shown in Table 21-9).
Bit time=
NOTE:
Pres value
• number of Time Quanta
fMSCANCLK
The CBTR1 register can only be written if the SFTRES bit in the
MSCAN08 module control register is set.
Technical Data
382
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
21.14.5 MSCAN08 Receiver Flag Register (CRFLG)
All bits of this register are read and clear only. A flag can be cleared by
writing a 1 to the corresponding bit position. A flag can be cleared only
when the condition which caused the setting is valid no more. Writing a
0 has no effect on the flag setting. Every flag has an associated interrupt
enable flag in the CRIER register. A hard or soft reset will clear the
register.
Address:
Read:
Write:
Reset:
$0504
Bit 7
6
5
4
3
2
1
Bit 0
WUPIF
RWRNIF
TWRNIF
RERRIF
TERRIF
BOFFIF
OVRIF
RXF
0
0
0
0
0
0
0
0
Figure 21-19. Receiver Flag Register (CRFLG)
WUPIF — Wakeup Interrupt Flag
If the MSCAN08 detects bus activity while in Sleep mode, it sets the
WUPIF flag. If not masked, a wake-up interrupt is pending while this
flag is set.
1 = MSCAN08 has detected activity on the bus and requested
wake-up.
0 = No wake-up interrupt has occurred.
RWRNIF — Receiver Warning Interrupt Flag
This flag is set when the MSCAN08 goes into warning status due to
the receive error counter (REC) exceeding 96 and neither one of the
Error Interrupt flags or the Bus-off Interrupt flag is set(1). If not
masked, an error interrupt is pending while this flag is set.
1 = MSCAN08 has gone into receiver warning status.
0 = No receiver warning status has been reached.
1. Condition to set the flag: RWRNIF = (96 ð REC) & RERRIF & TERRIF & BOFFIF
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
383
MSCAN08 Controller (MSCAN08)
TWRNIF — Transmitter Warning Interrupt Flag
This flag is set when the MSCAN08 goes into warning status due to
the transmit error counter (TEC) exceeding 96 and neither one of the
error interrupt flags or the bus-off interrupt flag is set(1). If not masked,
an error interrupt is pending while this flag is set.
1 = MSCAN08 has gone into transmitter warning status.
0 = No transmitter warning status has been reached.
RERRIF — Receiver Error Passive Interrupt Flag
This flag is set when the MSCAN08 goes into error passive status due
to the receive error counter exceeding 127 and the bus-off interrupt
flag is not set(2). If not masked, an Error interrupt is pending while this
flag is set.
1 = MSCAN08 has gone into receiver error passive status.
0 = No receiver error passive status has been reached.
TERRIF — Transmitter Error Passive Interrupt Flag
This flag is set when the MSCAN08 goes into error passive status due
to the Transmit Error counter exceeding 127 and the Bus-off interrupt
flag is not set(3). If not masked, an Error interrupt is pending while this
flag is set.
1 = MSCAN08 went into transmit error passive status.
0 = No transmit error passive status has been reached.
BOFFIF — Bus-Off Interrupt Flag
This flag is set when the MSCAN08 goes into bus-off status, due to
the transmit error counter exceeding 255. It cannot be cleared before
the MSCAN08 has monitored 128 times 11 consecutive ‘recessive’
bits on the bus. If not masked, an Error interrupt is pending while this
flag is set.
1 = MSCAN08has gone into bus-off status.
0 = No bus-off status has bee reached.
1. Condition to set the flag: TWRNIF = (96 ð TEC) & RERRIF & TERRIF & BOFFIF
2. Condition to set the flag: RERRIF = (127 ð REC ð 255) & BOFFIF
3. Condition to set the flag: TERRIF = (128 ð TEC ð 255) & BOFFIF
Technical Data
384
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
OVRIF — Overrun Interrupt Flag
This flag is set when a data overrun condition occurs. If not masked,
an error interrupt is pending while this flag is set.
1 = A data overrun has been detected since last clearing the flag.
0 = No data overrun has occurred.
RXF — Receive Buffer Full
The RXF flag is set by the MSCAN08 when a new message is
available in the foreground receive buffer. This flag indicates whether
the buffer is loaded with a correctly received message. After the CPU
has read that message from the receive buffer the RXF flag must be
cleared to release the buffer. A set RXF flag prohibits the exchange
of the background receive buffer into the foreground buffer. If not
masked, a receive interrupt is pending while this flag is set.
1 = The receive buffer is full. A new message is available.
0 = The receive buffer is released (not full).
NOTE:
To ensure data integrity, no registers of the receive buffer shall be read
while the RXF flag is cleared.
NOTE:
The CRFLG register is held in the reset state when the SFTRES bit in
CMCR0 is set.
21.14.6 MSCAN08 Receiver Interrupt Enable Register
Address:
Read:
Write:
Reset:
$0505
Bit 7
6
5
4
3
2
1
Bit 0
WUPIE
RWRNIE
TWRNIE
RERRIE
TERRIE
BOFFIE
OVRIE
RXFIE
0
0
0
0
0
0
0
0
Figure 21-20. Receiver Interrupt Enable Register (CRIER)
WUPIE — Wakeup Interrupt Enable
1 = A wakeup event will result in a wakeup interrupt.
0 = No interrupt will be generated from this event.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
385
MSCAN08 Controller (MSCAN08)
RWRNIE — Receiver Warning Interrupt Enable
1 = A receiver warning status event will result in an error interrupt.
0 = No interrupt is generated from this event.
TWRNIE — Transmitter Warning Interrupt Enable
1 = A transmitter warning status event will result in an error
interrupt.
0 = No interrupt is generated from this event.
RERRIE — Receiver Error Passive Interrupt Enable
1 = A receiver error passive status event will result in an error
interrupt.
0 = No interrupt is generated from this event.
TERRIE — Transmitter Error Passive Interrupt Enable
1 = A transmitter error passive status event will result in an error
interrupt.
0 = No interrupt is generated from this event.
BOFFIE — Bus-Off Interrupt Enable
1 = A bus-off event will result in an error interrupt.
0 = No interrupt is generated from this event.
OVRIE — Overrun Interrupt Enable
1 = An overrun event will result in an error interrupt.
0 = No interrupt is generated from this event.
RXFIE — Receiver Full Interrupt Enable
1 = A receive buffer full (successful message reception) event will
result in a receive interrupt.
0 = No interrupt will be generated from this event.
NOTE:
The CRIER register is held in the reset state when the SFTRES bit in
CMCR0 is set.
Technical Data
386
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
21.14.7 MSCAN08 Transmitter Flag Register
The Abort Acknowledge flags are read only. The Transmitter Buffer
Empty flags are read and clear only. A flag can be cleared by writing a 1
to the corresponding bit position. Writing a 0 has no effect on the flag
setting. The Transmitter Buffer Empty flags each have an associated
interrupt enable bit in the CTCR register. A hard or soft reset will resets
the register.
Address:
Read:
$0506
5
Bit 7
6
5
4
3
0
ABTAK2
ABTAK1
ABTAK0
0
0
0
0
0
0
Write:
Reset:
2
1
Bit 0
TXE2
TXE1
TXE0
1
1
1
= Unimplemented
Figure 21-21. Transmitter Flag Register (CTFLG)
ABTAK2–ABTAK0 — Abort Acknowledge
This flag acknowledges that a message has been aborted due to a
pending abort request from the CPU. After a particular message
buffer has been flagged empty, this flag can be used by the
application software to identify whether the message has been
aborted successfully or has been sent. The ABTAKx flag is cleared
implicitly whenever the corresponding TXE flag is cleared.
1 = The message has been aborted.
0 = The message has not been aborted, thus has been sent out.
TXE2–TXE0 — Transmitter Empty
This flag indicates that the associated transmit message buffer is
empty, thus not scheduled for transmission. The CPU must
handshake (clear) the flag after a message has been set up in the
transmit buffer and is due for transmission. The MSCAN08 sets the
flag after the message has been sent successfully. The flag is also set
by the MSCAN08 when the transmission request was successfully
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
387
MSCAN08 Controller (MSCAN08)
aborted due to a pending abort request (see Transmit Buffer
Priority Registers on page 374). If not masked, a receive interrupt is
pending while this flag is set.
Clearing a TXEx flag also clears the corresponding ABTAKx flag
(ABTAK, see above). When a TXEx flag is set, the corresponding
ABTRQx bit (ABTRQ, see MSCAN08 Transmitter Control Register)
is cleared.
1 = The associated message buffer is empty (not scheduled).
0 = The associated message buffer is full (loaded with a message
due for transmission).
NOTE:
To ensure data integrity, no registers of the transmit buffers should be
written to while the associated TXE flag is cleared.
NOTE:
The CTFLG register is held in the reset state when the SFTRES bit in
CMCR0 is set.
21.14.8 MSCAN08 Transmitter Control Register
Address:
$0507
Bit 7
Read:
0
Write:
Reset:
0
6
5
4
ABTRQ2
ABTRQ1
ABTRQ0
0
0
0
3
0
0
2
1
Bit 0
TXEIE2
TXEIE1
TXEIE0
0
0
0
= Unimplemented
Figure 21-22. Transmitter Control Register (CTCR)
ABTRQ2–ABTRQ0 — Abort Request
The CPU sets an ABTRQx bit to request that an already scheduled
message buffer (TXE = 0) be aborted. The MSCAN08 will grant the
request if the message has not already started transmission, or if the
transmission is not successful (lost arbitration or error). When a
message is aborted the associated TXE and the abort acknowledge
flag (ABTAK) (see MSCAN08 Transmitter Flag Register on page
Technical Data
388
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
387) will be set and an TXE interrupt is generated if enabled. The
CPU cannot reset ABTRQx. ABTRQx is cleared implicitly whenever
the associated TXE flag is set.
1 = Abort request pending
0 = No abort request
NOTE:
The software must not clear one or more of the TXE flags in CTFLG and
simultaneously set the respective ABTRQ bit(s).
TXEIE2–TXEIE0 — Transmitter Empty Interrupt Enable
1 = A transmitter empty (transmit buffer available for transmission)
event results in a transmitter empty interrupt.
0 = No interrupt is generated from this event.
NOTE:
The CTCR register is held in the reset state when the SFTRES bit in
CMCR0 is set.
21.14.9 MSCAN08 Identifier Acceptance Control Register
Address:
Read:
$0508
Bit 7
6
0
0
0
0
Write:
Reset:
5
4
IDAM1
IDAM0
0
0
3
2
1
Bit 0
0
0
IDHIT1
IDHIT0
0
0
0
0
= Unimplemented
Figure 21-23. Identifier Acceptance Control Register (CIDAC)
IDAM1–IDAM0— Identifier Acceptance Mode
The CPU sets these flags to define the identifier acceptance filter
organization (see Identifier Acceptance Filter on page 352). Table
21-9 summarizes the different settings. In “filter closed” mode no
messages will be accepted so that the foreground buffer will never be
reloaded.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
389
MSCAN08 Controller (MSCAN08)
Table 21-9. Identifier Acceptance Mode Settings
IDAM1
IDAM0
Identifier Acceptance Mode
0
0
Single 32-Bit Acceptance Filter
0
1
Two 16-Bit Acceptance Filter
1
0
Four 8-Bit Acceptance Filters
1
1
Filter Closed
IDHIT1–IDHIT0— Identifier Acceptance Hit Indicator
The MSCAN08 sets these flags to indicate an identifier acceptance hit
(see Identifier Acceptance Filter on page 352). Table 21-9
summarizes the different settings.
Table 21-10. Identifier Acceptance Hit Indication
IDHIT1
IDHIT0
Identifier Acceptance Hit
0
0
Filter 0 Hit
0
1
Filter 1 Hit
1
0
Filter 2 Hit
1
1
Filter 3 Hit
The IDHIT indicators are always related to the message in the
foreground buffer. When a message gets copied from the background to
the foreground buffer, the indicators are updated as well.
NOTE:
The CIDAC register can be written only if the SFTRES bit in the CMCR0
is set.
Technical Data
390
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
21.14.10 MSCAN08 Receive Error Counter
Address:
$050E
Bit 7
Read: RXERR7
6
5
4
3
2
1
Bit 0
RXERR6
RXERR5
RXERR4
RXERR3
RXERR2
RXERR1
RXERR0
0
0
0
0
0
0
0
Write:
Reset:
0
= Unimplemented
Figure 21-24. Receiver Error Counter (CRXERR)
This register reflects the status of the MSCAN08 receive error counter.
The register is read only.
21.14.11 MSCAN08 Transmit Error Counter
Address:
$050F
Bit 7
Read: TXERR7
6
5
4
3
2
1
Bit 0
TXERR6
TXERR5
TXERR4
TXERR3
TXERR2
TXERR1
TXERR0
0
0
0
0
0
0
0
Write:
Reset:
0
= Unimplemented
Figure 21-25. Transmit Error Counter (CTXERR)
This register reflects the status of the MSCAN08 transmit error counter.
The register is read only.
NOTE:
Both error counters may only be read when in Sleep or Soft Reset mode.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
391
MSCAN08 Controller (MSCAN08)
21.14.12 MSCAN08 Identifier Acceptance Registers
On reception each message is written into the background receive
buffer. The CPU is only signalled to read the message, however, if it
passes the criteria in the identifier acceptance and identifier mask
registers (accepted); otherwise, the message will be overwritten by the
next message (dropped).
The acceptance registers of the MSCAN08 are applied on the IDR0 to
IDR3 registers of incoming messages in a bit by bit manner.
For extended identifiers, all four acceptance and mask registers are
applied. For standard identifiers only the first two (CIDMR0/1 and
CIDAR0/1) are applied.
CIDAR0
Read:
Write:
Address: $0510
Bit 7
6
5
4
3
2
1
Bit 0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
Reset:
CIDAR1
Read:
Write:
Unaffected by Reset
Address: $0511
Bit 7
6
5
4
3
2
1
Bit 0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
Reset:
CIDAR2
Read:
Write:
Unaffected by Reset
Address: $0512
Bit 7
6
5
4
3
2
1
Bit 0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
Reset:
CIDAR3
Read:
Write:
Reset:
Unaffected by Reset
Address: $0513
Bit 7
6
5
4
3
2
1
Bit 0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
Unaffected by Reset
Figure 21-26. Identifier Acceptance Registers (CIDAR0–CIDAR3)
Technical Data
392
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
MSCAN08 Controller (MSCAN08)
AC7–AC0 — Acceptance Code Bits
AC7–AC0 comprise a user-defined sequence of bits with which the
corresponding bits of the related identifier register (IDRn) of the
receive message buffer are compared. The result of this comparison
is then masked with the corresponding identifier mask register.
NOTE:
The CIDAR0–3 registers can be written only if the SFTRES bit in
CMCR0 is set
21.14.13 MSCAN08 Identifier Mask Registers (CIDMR0-3)
The identifier mask registers specify which of the corresponding bits in
the identifier acceptance register are relevant for acceptance filtering.
For standard identifiers it is required to program the last three bits (AM2AM0) in the mask register CIDMR1 to ‘don’t care’.
CIDMRO
Read:
Write:
Address: $0514
Bit 7
6
5
4
3
2
1
Bit 0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
Reset:
CIDMR1
Read:
Write:
Unaffected by Reset
Address: $0515
Bit 7
6
5
4
3
2
1
Bit 0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
Reset:
CIDMR2
Read:
Write:
Unaffected by Reset
Address: $0516
Bit 7
6
5
4
3
2
1
Bit 0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
Reset:
CIDMR3
Read:
Write:
Reset:
Unaffected by Reset
Address: $0517
Bit 7
6
5
4
3
2
1
Bit 0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
Unaffected by Reset
Figure 21-27. Identifier Mask Registers (CIDMR0–CIDMR3)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MSCAN08 Controller (MSCAN08)
393
MSCAN08 Controller (MSCAN08)
AM7–AM0 — Acceptance Mask Bits
If a particular bit in this register is cleared, this indicates that the
corresponding bit in the identifier acceptance register must be the
same as its identifier bit before a match will be detected. The
message will be accepted if all such bits match. If a bit is set, it
indicates that the state of the corresponding bit in the identifier
acceptance register will not affect whether or not the message is
accepted.
1 = Ignore corresponding acceptance code register bit.
0 = Match corresponding acceptance code register and identifier
bits.
NOTE:
The CIDMR0-3 registers can be written only if the SFTRES bit in the
CMCR0 is set
Technical Data
394
MC68HC08AZ60A — Rev 2.1
MSCAN08 Controller (MSCAN08)
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 22. Keyboard Module (KBD)
22.1 Contents
22.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
22.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .396
22.4
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
22.5
Keyboard Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
22.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
22.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
22.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
22.7
Keyboard Module During Break Interrupts . . . . . . . . . . . . 400
22.8 I/O Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .401
22.8.1 Keyboard Status and Control Register . . . . . . . . . . . . . 401
22.8.2 Keyboard Interrupt Enable Register. . . . . . . . . . . . . . . . 402
22.2 Introduction
The keyboard interrupt module (KBD) provides five independently
maskable external interrupt pins.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Keyboard Module (KBD)
395
Keyboard Module (KBD)
22.3 Features
KBD features include:
•
Five Keyboard Interrupt Pins with Separate Keyboard Interrupt
Enable Bits and One Keyboard Interrupt Mask
•
Hysteresis Buffers
•
Programmable Edge-Only or Edge- and Level- Interrupt Sensitivity
•
Automatic Interrupt Acknowledge
•
Exit from Low-Power Modes
22.4 Functional Description
Writing to the KBIE4–KBIE0 bits in the keyboard interrupt enable register
independently enables or disables each port G or port H pin as a
keyboard interrupt pin. Enabling a keyboard interrupt pin also enables its
internal pullup device. A logic 0 applied to an enabled keyboard interrupt
pin latches a keyboard interrupt request.
A keyboard interrupt is latched when one or more keyboard pins goes
low after all were high. The MODEK bit in the keyboard status and
control register controls the triggering mode of the keyboard interrupt.
•
If the keyboard interrupt is edge-sensitive only, a falling edge on a
keyboard pin does not latch an interrupt request if another
keyboard pin is already low. To prevent losing an interrupt request
on one pin because another pin is still low, software can disable
the latter pin while it is low.
•
If the keyboard interrupt is falling edge- and low level-sensitive, an
interrupt request is present as long as any keyboard pin is low.
Technical Data
396
MC68HC08AZ60A — Rev 2.1
Keyboard Module (KBD)
Freescale Semiconductor
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
INTERNAL BUS
KBD0
ACKK
VDD
.
TO PULLUP ENABLE
KB0IE
D
.
CLR
VECTOR FETCH
DECODER
KEYF
RESET
Q
SYNCHRONIZER
CK
.
KEYBOARD
INTERRUPT FF
KBD4
KEYBOARD
INTERRUPT
REQUEST
IMASKK
MODEK
TO PULLUP ENABLE
Keyboard Module (KBD)
KB4IE
Figure 22-1. Keyboard Module Block Diagram
Register Name
Read:
Keyboard Status and Control RegWrite:
ister (KBSCR)
Reset:
Read:
Keyboard Interrupt Enable RegisWrite:
ter (KBIER)
Reset:
Bit 7
0
6
0
5
0
4
0
3
KEYF
1
Bit 0
IMASKK
MODEK
0
2
0
ACKK
0
0
0
0
0
0
0
0
0
0
KBIE4
KBIE3
KBIE2
KBIE1
KBIE0
0
0
0
0
0
0
0
0
= Unimplemented
Figure 22-2. I/O Register Summary
397
Technical Data
Register
KBSCR
KBIER
Address
$001A
$001B
Keyboard Module (KBD)
Table 22-1. I/O Register Address Summary
Keyboard Module (KBD)
If the MODEK bit is set, the keyboard interrupt pins are both falling edgeand low level-sensitive, and both of the following actions must occur to
clear a keyboard interrupt request:
•
Vector fetch or software clear — A vector fetch generates an
interrupt acknowledge signal to clear the interrupt request.
Software may generate the interrupt acknowledge signal by
writing a logic 1 to the ACKK bit in the keyboard status and control
register (KBSCR). The ACKK bit is useful in applications that poll
the keyboard interrupt pins and require software to clear the
keyboard interrupt request. Writing to the ACKK bit prior to leaving
an interrupt service routine also can prevent spurious interrupts
due to noise. Setting ACKK does not affect subsequent transitions
on the keyboard interrupt pins. A falling edge that occurs after
writing to the ACKK bit latches another interrupt request. If the
keyboard interrupt mask bit, IMASKK, is clear, the CPU loads the
program counter with the vector address at locations $FFDE and
$FFDF.
•
Return of all enabled keyboard interrupt pins to logic 1. As long as
any enabled keyboard interrupt pin is at logic 0, the keyboard
interrupt remains set.
The vector fetch or software clear and the return of all enabled keyboard
interrupt pins to logic 1 may occur in any order.
If the MODEK bit is clear, the keyboard interrupt pin is falling edgesensitive only. With MODEK clear, a vector fetch or software clear
immediately clears the keyboard interrupt request.
Reset clears the keyboard interrupt request and the MODEK bit, clearing
the interrupt request even if a keyboard interrupt pin stays at logic 0.
The keyboard flag bit (KEYF) in the keyboard status and control register
can be used to see if a pending interrupt exists. The KEYF bit is not
affected by the keyboard interrupt mask bit (IMASKK) which makes it
useful in applications where polling is preferred.
To determine the logic level on a keyboard interrupt pin, use the data
direction register to configure the pin as an input and read the data
register.
Technical Data
398
MC68HC08AZ60A — Rev 2.1
Keyboard Module (KBD)
Freescale Semiconductor
Keyboard Module (KBD)
NOTE:
Setting a keyboard interrupt enable bit (KBIEx) forces the corresponding
keyboard interrupt pin to be an input, overriding the data direction
register. However, the data direction register bit must be a logic 0 for
software to read the pin.
22.5 Keyboard Initialization
When a keyboard interrupt pin is enabled, it takes time for the internal
pullup to reach a logic 1. Therefore, a false interrupt can occur as soon
as the pin is enabled.
To prevent a false interrupt on keyboard initialization:
1. Mask keyboard interrupts by setting the IMASKK bit in the
keyboard status and control register
2. Enable the KBI pins by setting the appropriate KBIEx bits in the
keyboard interrupt enable register
3. Write to the ACKK bit in the keyboard status and control register
to clear any false interrupts
4. Clear the IMASKK bit.
An interrupt signal on an edge-triggered pin can be acknowledged
immediately after enabling the pin. An interrupt signal on an edge- and
level-triggered interrupt pin must be acknowledged after a delay that
depends on the external load.
Another way to avoid a false interrupt:
1. Configure the keyboard pins as outputs by setting the appropriate
DDRG bits in data direction register G.
2. Configure the keyboard pins as outputs by setting the appropriate
DDRH bits in data direction register H.
3. Write logic 1s to the appropriate port G and port H data register
bits.
4. Enable the KBI pins by setting the appropriate KBIEx bits in the
keyboard interrupt enable register.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Keyboard Module (KBD)
399
Keyboard Module (KBD)
22.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low-powerconsumption standby modes.
22.6.1 Wait Mode
The keyboard module remains active in wait mode. Clearing the
IMASKK bit in the keyboard status and control register enables keyboard
interrupt requests to bring the MCU out of wait mode.
22.6.2 Stop Mode
The keyboard module remains active in stop mode. Clearing the
IMASKK bit in the keyboard status and control register enables keyboard
interrupt requests to bring the MCU out of stop mode.
22.7 Keyboard Module During Break Interrupts
The BCFE bit in the break flag control register (BFCR) enables software
to clear status bits during the break state. See Break Module on page
171.
To allow software to clear the KEYF bit during a break interrupt, write a
logic 1 to the BCFE bit. If KEYF is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect the KEYF bit during the break state, write a logic 0 to the
BCFE bit. With BCFE at logic 0, writing to the keyboard acknowledge bit
(ACKK) in the keyboard status and control register during the break state
has no effect. See Keyboard Status and Control Register on page
401.
Technical Data
400
MC68HC08AZ60A — Rev 2.1
Keyboard Module (KBD)
Freescale Semiconductor
Keyboard Module (KBD)
22.8 I/O Registers
The following registers control and monitor operation of the keyboard
module:
•
Keyboard status and control register (KBSCR)
•
Keyboard interrupt enable register (KBIER)
22.8.1 Keyboard Status and Control Register
The keyboard status and control register:
•
Flags keyboard interrupt requests
•
Acknowledges keyboard interrupt requests
•
Masks keyboard interrupt requests
•
Controls keyboard interrupt triggering sensitivity
Address: $001A
Read:
Bit 7
6
5
4
3
2
0
0
0
0
KEYF
0
Write:
Reset:
ACKK
0
0
0
0
0
0
1
Bit 0
IMASKK
MODEK
0
0
= Unimplemented
Figure 22-3. Keyboard Status and Control Register (KBSCR)
Bits 7–4 — Not used
These read-only bits always read as logic 0s.
KEYF — Keyboard Flag Bit
This read-only bit is set when a keyboard interrupt is pending. Reset
clears the KEYF bit.
1 = Keyboard interrupt pending
0 = No keyboard interrupt pending
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Keyboard Module (KBD)
401
Keyboard Module (KBD)
ACKK — Keyboard Acknowledge Bit
Writing a logic 1 to this write-only bit clears the keyboard interrupt
request. ACKK always reads as logic 0. Reset clears ACKK.
IMASKK — Keyboard Interrupt Mask Bit
Writing a logic 1 to this read/write bit prevents the output of the
keyboard interrupt mask from generating interrupt requests. Reset
clears the IMASKK bit.
1 = Keyboard interrupt requests masked
0 = Keyboard interrupt requests not masked
MODEK — Keyboard Triggering Sensitivity Bit
This read/write bit controls the triggering sensitivity of the keyboard
interrupt pins. Reset clears MODEK.
1 = Keyboard interrupt requests on falling edges and low levels
0 = Keyboard interrupt requests on falling edges only
22.8.2 Keyboard Interrupt Enable Register
The keyboard interrupt enable register enables or disables each port G
and each port H pin to operate as a keyboard interrupt pin.
Address: $001B
Read:
Bit 7
6
5
0
0
0
0
0
0
Write:
Reset:
4
3
2
1
Bit 0
KBIE4
KBIE3
KBIE2
KBIE1
KBIE0
0
0
0
0
0
= Unimplemented
Figure 22-4. Keyboard Interrupt Enable Register (KBIER)
KBIE4–KBIE0 — Keyboard Interrupt Enable Bits
Each of these read/write bits enables the corresponding keyboard
interrupt pin to latch interrupt requests. Reset clears the keyboard
interrupt enable register.
1 = Port pin enabled as keyboard interrupt pin
0 = Port pin not enabled as keyboard interrupt pin
Technical Data
402
MC68HC08AZ60A — Rev 2.1
Keyboard Module (KBD)
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 23. Timer Interface Module A (TIMA)
23.1 Contents
23.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
23.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .404
23.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
23.4.1 TIMA Counter Prescaler. . . . . . . . . . . . . . . . . . . . . . . . . . 408
23.4.2 Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
23.4.3 Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
23.4.3.1
Unbuffered Output Compare. . . . . . . . . . . . . . . . . . . .409
23.4.3.2
Buffered Output Compare . . . . . . . . . . . . . . . . . . . . . . 410
23.4.4 Pulse Width Modulation (PWM) . . . . . . . . . . . . . . . . . . . 412
23.4.4.1
Unbuffered PWM Signal Generation . . . . . . . . . . . . . 413
23.4.4.2
Buffered PWM Signal Generation. . . . . . . . . . . . . . . . 414
23.4.4.3
PWM Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
23.5
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
23.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
23.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
23.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
23.7
TIMA During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . .418
23.8 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
23.8.1 TIMA Clock Pin (PTD6/ATD14/TACLK) . . . . . . . . . . . . . . 418
23.8.2 TIMA Channel I/O Pins (PTF3–PTF0/TACH2 and
PTE3/TACH1–PTE2/TACH0) . . . . . . . . . . . . . . . . . . . . . . 419
23.9 I/O Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .419
23.9.1 TIMA Status and Control Register . . . . . . . . . . . . . . . . . 420
23.9.2 TIMA Counter Registers . . . . . . . . . . . . . . . . . . . . . . . . . 422
23.9.3 TIMA Counter Modulo Registers. . . . . . . . . . . . . . . . . . . 423
23.9.4 TIMA Channel Status and Control Registers. . . . . . . . . 424
23.9.5 TIMA Channel Registers . . . . . . . . . . . . . . . . . . . . . . . . . 429
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
403
Timer Interface Module A (TIMA)
23.2 Introduction
This section describes the timer interface module (TIMA). The TIMA is a
6-channel timer that provides a timing reference with input capture,
output compare and pulse-width-modulation functions. Figure 23-1 is a
block diagram of the TIMA.
For further information regarding timers on M68HC08 family devices,
please consult the HC08 Timer Reference Manual, TIM08RM/AD.
23.3 Features
Features of the TIMA include:
•
Six Input Capture/Output Compare Channels
– Rising-Edge, Falling-Edge or Any-Edge Input Capture Trigger
– Set, Clear or Toggle Output Compare Action
•
Buffered and Unbuffered Pulse Width Modulation (PWM) Signal
Generation
•
Programmable TIMA Clock Input
– 7 Frequency Internal Bus Clock Prescaler Selection
– External TIMA Clock Input (4 MHz Maximum Frequency)
•
Free-Running or Modulo Up-Count Operation
•
Toggle Any Channel Pin on Overflow
•
TIMA Counter Stop and Reset Bits
Technical Data
404
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
TCLK
PTD6/ATD14/TACLK
INTERNAL
BUS CLOCK
PRESCALER SELECT
PRESCALER
TSTOP
PS2
TRST
PS1
PS0
16-BIT COUNTER
TOF
TOIE
INTERRUPT
LOGIC
16-BIT COMPARATOR
TMODH:TMODL
CHANNEL 0
ELS0B
ELS0A
TOV0
CH0MAX
16-BIT COMPARATOR
TCH0H:TCH0L
CH0F
16-BIT LATCH
MS0A
CHANNEL 1
ELS1B
MS0B
ELS1A
TOV1
CH1MAX
16-BIT COMPARATOR
TCH1H:TCH1L
CH1F
16-BIT LATCH
CH1IE
MS1A
CHANNEL 2
ELS2B
ELS2A
TOV2
CH2MAX
16-BIT COMPARATOR
TCH2H:TCH2L
CH2F
16-BIT LATCH
MS2A
CHANNEL 3
ELS3B
MS2B
ELS3A
TCH3H:TCH3L
CH3F
16-BIT LATCH
CH3IE
MS3A
ELS4B
ELS4A
TOV4
CH5MAX
16-BIT COMPARATOR
TCH4H:TCH4L
CH4F
16-BIT LATCH
MS4A
CHANNEL 5
CH2IE
TOV3
CH3MAX
16-BIT COMPARATOR
CHANNEL 4
CH0IE
ELS5B
MS4B
ELS5A
TOV5
CH5MAX
16-BIT COMPARATOR
TCH5H:TCH5L
CH4IE
CH5F
16-BIT LATCH
MS5A
CH5IE
PTE2
LOGIC
PTE2/TACH0
INTERRUPT
LOGIC
PTE3
LOGIC
PTE3/TACH1
INTERRUPT
LOGIC
PTF0
LOGIC
PTF0/TACH2
INTERRUPT
LOGIC
PTF1
LOGIC
PTF1/TACH3
INTERRUPT
LOGIC
PTF2
LOGIC
PTF2/TACH4
INTERRUPT
LOGIC
PTF3
LOGIC
PTF3/TACH5
INTERRUPT
LOGIC
Figure 23-1. TIMA Block Diagram
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
405
Timer Interface Module A (TIMA)
Figure 23-2. TIMA I/O Register Summary
Addr.
Register Name
Bit 7
$0020
TIMA Status/Control Register (TASC)
$0022
TIMA Counter Register High (TACNTH)
$0023
TIMA Counter Register Low (TACNTL)
6
5
TOIE
TSTOP
4
3
0
0
TRST
R
2
1
Bit 0
PS2
PS1
PS0
R:
TOF
W:
0
R:
Bit 15
14
13
12
11
10
9
Bit 8
W:
R
R
R
R
R
R
R
R
R:
Bit 7
6
5
4
3
2
1
Bit 0
W:
R
R
R
R
R
R
R
R
$0024
TIMA Counter Modulo Reg. High R:
(TAMODH) W:
Bit 15
14
13
12
11
10
9
Bit 8
$0025
TIMA Counter Modulo Reg. Low R:
(TAMODL) W:
Bit 7
6
5
4
3
2
1
Bit 0
$0026
TIMA Ch. 0 Status/Control Register R:
(TASC0) W:
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
Bit 15
14
13
12
11
10
9
Bit 8
Bit 7
6
5
4
3
2
1
Bit 0
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
R:
$0027
TIMA Ch. 0 Register High (TACH0H)
$0028
TIMA Ch. 0 Register Low (TACH0L)
$0029
TIMA Ch. 1 Status/Control Register R:
(TASC1) W:
W:
R:
W:
R:
$002A
TIMA Ch. 1 Register High (TACH1H)
$002B
TIMA Ch. 1 Register Low (TACH1L)
$002C
TIMA Ch. 2 Status/Control Register R:
(TASC2) W:
W:
R:
W:
R:
$002D
TIMA Ch. 2 Register High (TACH2H)
$002E
TIMA Ch. 2 Register Low (TACH2L)
$002F
TIMA Ch. 3 Status/Control Register R:
(TASC3) W:
$0030
TIMA Ch. 3 Register High (TACH3H)
$0031
TIMA Ch. 3 Register Low (TACH3L)
W:
R:
W:
R:
W:
R:
W:
CH0F
0
CH1F
0
CH1IE
0
R
Bit 15
14
13
12
11
10
9
Bit 8
Bit 7
6
5
4
3
2
1
Bit 0
CH2IE
MS2B
MS2A
ELS2B
ELS2A
TOV2
CH2MAX
Bit 15
14
13
12
11
10
9
Bit 8
Bit 7
6
5
4
3
2
1
Bit 0
MS3A
ELS3B
ELS3A
TOV3
CH3MAX
CH2F
0
CH3F
0
CH3IE
0
R
Bit 15
14
13
12
11
10
9
Bit 8
Bit 7
6
5
4
3
2
1
Bit 0
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Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
Figure 23-2. TIMA I/O Register Summary
Addr.
$0032
Register Name
Bit 7
TIMA Ch. 4 Status/Control Register R:
(TASC4) W:
R:
$0033
TIMA Ch. 4 Register High (TACH4H)
$0034
TIMA Ch. 4 Register Low (TACH4L)
$0035
TIMA Ch. 5 Status/Control Register R:
(TASC5) W:
$0036
TIMA Ch. 5 Register High (TACH5H)
$0037
TIMA Ch. 5 Register Low (TACH5L)
W:
R:
W:
R:
W:
R:
W:
6
5
4
3
2
1
Bit 0
CH4IE
MS4B
MS4A
ELS4B
ELS4A
TOV4
CH4MAX
Bit 15
14
13
12
11
10
9
Bit 8
Bit 7
6
5
4
3
2
1
Bit 0
MS5A
ELS5B
ELS5A
TOV5
CH5MAX
CH4F
0
CH5F
0
CH5IE
0
R
Bit 15
14
13
12
11
10
9
Bit 8
Bit 7
6
5
4
3
2
1
Bit 0
R
= Reserved
23.4 Functional Description
Figure 23-1 shows the TIMA structure. The central component of the
TIMA is the 16-bit TIMA counter that can operate as a free-running
counter or a modulo up-counter. The TIMA counter provides the timing
reference for the input capture and output compare functions. The TIMA
counter modulo registers, TAMODH–TAMODL, control the modulo
value of the TIMA counter. Software can read the TIMA counter value at
any time without affecting the counting sequence.
The six TIMA channels are programmable independently as input
capture or output compare channels.
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Technical Data
Timer Interface Module A (TIMA)
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Timer Interface Module A (TIMA)
23.4.1 TIMA Counter Prescaler
The TIMA clock source can be one of the seven prescaler outputs or the
TIMA clock pin, PTD6/ATD14/TACLK. The prescaler generates seven
clock rates from the internal bus clock. The prescaler select bits, PS[2:0],
in the TIMA status and control register select the TIMA clock source.
23.4.2 Input Capture
An input capture function has three basic parts: edge select logic, an
input capture latch and a 16-bit counter. Two 8-bit registers, which make
up the 16-bit input capture register, are used to latch the value of the
free-running counter after the corresponding input capture edge detector
senses a defined transition. The polarity of the active edge is
programmable. The level transition which triggers the counter transfer is
defined by the corresponding input edge bits (ELSxB and ELSxA in
TASC0 through TASC5 control registers with x referring to the active
channel number). When an active edge occurs on the pin of an input
capture channel, the TIMA latches the contents of the TIMA counter into
the TIMA channel registers, TACHxH–TACHxL. Input captures can
generate TIMA CPU interrupt requests. Software can determine that an
input capture event has occurred by enabling input capture interrupts or
by polling the status flag bit.
The free-running counter contents are transferred to the TIMA channel
register (TACHxH–TACHxL see TIMA Channel Registers on page 429)
on each proper signal transition regardless of whether the TIMA channel
flag (CH0F–CH5F in TASC0–TASC5 registers) is set or clear. When the
status flag is set, a CPU interrupt is generated if enabled. The value of
the count latched or “captured” is the time of the event. Because this
value is stored in the input capture register 2 bus cycles after the actual
event occurs, user software can respond to this event at a later time and
determine the actual time of the event. However, this must be done prior
to another input capture on the same pin; otherwise, the previous time
value will be lost.
By recording the times for successive edges on an incoming signal,
software can determine the period and/or pulse width of the signal. To
measure a period, two successive edges of the same polarity are
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Freescale Semiconductor
Timer Interface Module A (TIMA)
captured. To measure a pulse width, two alternate polarity edges are
captured. Software should track the overflows at the 16-bit module
counter to extend its range.
Another use for the input capture function is to establish a time
reference. In this case, an input capture function is used in conjunction
with an output compare function. For example, to activate an output
signal a specified number of clock cycles after detecting an input event
(edge), use the input capture function to record the time at which the
edge occurred. A number corresponding to the desired delay is added to
this captured value and stored to an output compare register (see TIMA
Channel Registers on page 429). Because both input captures and
output compares are referenced to the same 16-bit modulo counter, the
delay can be controlled to the resolution of the counter independent of
software latencies.
Reset does not affect the contents of the TIMA channel register
(TACHxH–TACHxL).
23.4.3 Output Compare
With the output compare function, the TIMA can generate a periodic
pulse with a programmable polarity, duration and frequency. When the
counter reaches the value in the registers of an output compare channel,
the TIMA can set, clear or toggle the channel pin. Output compares can
generate TIMA CPU interrupt requests.
23.4.3.1 Unbuffered Output Compare
Any output compare channel can generate unbuffered output compare
pulses as described in Output Compare on page 409. The pulses are
unbuffered because changing the output compare value requires writing
the new value over the old value currently in the TIMA channel registers.
An unsynchronized write to the TIMA channel registers to change an
output compare value could cause incorrect operation for up to two
counter overflow periods. For example, writing a new value before the
counter reaches the old value but after the counter reaches the new
value prevents any compare during that counter overflow period. Also,
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Technical Data
Timer Interface Module A (TIMA)
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Timer Interface Module A (TIMA)
using a TIMA overflow interrupt routine to write a new, smaller output
compare value may cause the compare to be missed. The TIMA may
pass the new value before it is written.
Use the following methods to synchronize unbuffered changes in the
output compare value on channel x:
•
When changing to a smaller value, enable channel x output
compare interrupts and write the new value in the output compare
interrupt routine. The output compare interrupt occurs at the end
of the current output compare pulse. The interrupt routine has until
the end of the counter overflow period to write the new value.
•
When changing to a larger output compare value, enable TIMA
overflow interrupts and write the new value in the TIMA overflow
interrupt routine. The TIMA overflow interrupt occurs at the end of
the current counter overflow period. Writing a larger value in an
output compare interrupt routine (at the end of the current pulse)
could cause two output compares to occur in the same counter
overflow period.
23.4.3.2 Buffered Output Compare
Channels 0 and 1 can be linked to form a buffered output compare
channel whose output appears on the PTE2/TACH0 pin. The TIMA
channel registers of the linked pair alternately control the output.
Setting the MS0B bit in TIMA channel 0 status and control register
(TASC0) links channel 0 and channel 1. The output compare value in the
TIMA channel 0 registers initially controls the output on the
PTE2/TACH0 pin. Writing to the TIMA channel 1 registers enables the
TIMA channel 1 registers to synchronously control the output after the
TIMA overflows. At each subsequent overflow, the TIMA channel
registers (0 or 1) that control the output are the ones written to last.
TASC0 controls and monitors the buffered output compare function and
TIMA channel 1 status and control register (TASC1) is unused. While the
MS0B bit is set, the channel 1 pin, PTE3/TACH1, is available as a
general-purpose I/O pin.
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Timer Interface Module A (TIMA)
Channels 2 and 3 can be linked to form a buffered output compare
channel whose output appears on the PTF0/TACH2 pin. The TIMA
channel registers of the linked pair alternately control the output.
Setting the MS2B bit in TIMA channel 2 status and control register
(TASC2) links channel 2 and channel 3. The output compare value in the
TIMA channel 2 registers initially controls the output on the
PTF0/TACH2 pin. Writing to the TIMA channel 3 registers enables the
TIMA channel 3 registers to synchronously control the output after the
TIMA overflows. At each subsequent overflow, the TIMA channel
registers (2 or 3) that control the output are the ones written to last.
TASC2 controls and monitors the buffered output compare function, and
TIMA channel 3 status and control register (TASC3) is unused. While the
MS2B bit is set, the channel 3 pin, PTF1/TACH3, is available as a
general-purpose I/O pin.
Channels 4 and 5 can be linked to form a buffered output compare
channel whose output appears on the PTF2 pin. The TIMA channel
registers of the linked pair alternately control the output.
Setting the MS4B bit in TIMA channel 4 status and control register
(TASC4) links channel 4 and channel 5. The output compare value in the
TIMA channel 4 registers initially controls the output on the PTF2 pin.
Writing to the TIMA channel 5 registers enables the TIMA channel 5
registers to synchronously control the output after the TIMA overflows.
At each subsequent overflow, the TIMA channel registers (4 or 5) that
control the output are the ones written to last. TASC4 controls and
monitors the buffered output compare function and TIMA channel 5
status and control register (TASC5) is unused. While the MS4B bit is set,
the channel 5 pin, PTF3, is available as a general-purpose I/O pin.
NOTE:
In buffered output compare operation, do not write new output compare
values to the currently active channel registers. User software should
track the currently active channel to prevent writing a new value to the
active channel. Writing to the active channel registers is the same as
generating unbuffered output compares.
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Technical Data
Timer Interface Module A (TIMA)
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Timer Interface Module A (TIMA)
23.4.4 Pulse Width Modulation (PWM)
By using the toggle-on-overflow feature with an output compare channel,
the TIMA can generate a PWM signal. The value in the TIMA counter
modulo registers determines the period of the PWM signal. The channel
pin toggles when the counter reaches the value in the TIMA counter
modulo registers. The time between overflows is the period of the PWM
signal.
As Figure 23-3 shows, the output compare value in the TIMA channel
registers determines the pulse width of the PWM signal. The time
between overflow and output compare is the pulse width. Program the
TIMA to clear the channel pin on output compare if the state of the PWM
pulse is logic 1. Program the TIMA to set the pin if the state of the PWM
pulse is logic 0.
OVERFLOW
OVERFLOW
OVERFLOW
PERIOD
PULSE
WIDTH
PTEx/TCHx
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
Figure 23-3. PWM Period and Pulse Width
The value in the TIMA counter modulo registers and the selected
prescaler output determines the frequency of the PWM output. The
frequency of an 8-bit PWM signal is variable in 256 increments. Writing
$00FF (255) to the TIMA counter modulo registers produces a PWM
period of 256 times the internal bus clock period if the prescaler select
value is $000 (see TIMA Status and Control Register on page 420).
The value in the TIMA channel registers determines the pulse width of
the PWM output. The pulse width of an 8-bit PWM signal is variable in
256 increments. Writing $0080 (128) to the TIMA channel registers
produces a duty cycle of 128/256 or 50%.
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Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
23.4.4.1 Unbuffered PWM Signal Generation
Any output compare channel can generate unbuffered PWM pulses as
described in Pulse Width Modulation (PWM) on page 412. The pulses
are unbuffered because changing the pulse width requires writing the
new pulse width value over the value currently in the TIMA channel
registers.
An unsynchronized write to the TIMA channel registers to change a
pulse width value could cause incorrect operation for up to two PWM
periods. For example, writing a new value before the counter reaches
the old value but after the counter reaches the new value prevents any
compare during that PWM period. Also, using a TIMA overflow interrupt
routine to write a new, smaller pulse width value may cause the compare
to be missed. The TIMA may pass the new value before it is written to
the TIMA channel registers.
Use the following methods to synchronize unbuffered changes in the
PWM pulse width on channel x:
NOTE:
•
When changing to a shorter pulse width, enable channel x output
compare interrupts and write the new value in the output compare
interrupt routine. The output compare interrupt occurs at the end
of the current pulse. The interrupt routine has until the end of the
PWM period to write the new value.
•
When changing to a longer pulse width, enable TIMA overflow
interrupts and write the new value in the TIMA overflow interrupt
routine. The TIMA overflow interrupt occurs at the end of the
current PWM period. Writing a larger value in an output compare
interrupt routine (at the end of the current pulse) could cause two
output compares to occur in the same PWM period.
In PWM signal generation, do not program the PWM channel to toggle
on output compare. Toggling on output compare prevents reliable 0%
duty cycle generation and removes the ability of the channel to selfcorrect in the event of software error or noise. Toggling on output
compare also can cause incorrect PWM signal generation when
changing the PWM pulse width to a new, much larger value.
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Technical Data
Timer Interface Module A (TIMA)
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Timer Interface Module A (TIMA)
23.4.4.2 Buffered PWM Signal Generation
Channels 0 and 1 can be linked to form a buffered PWM channel whose
output appears on the PTE2/TACH0 pin. The TIMA channel registers of
the linked pair alternately control the pulse width of the output.
Setting the MS0B bit in TIMA channel 0 status and control register
(TASC0) links channel 0 and channel 1. The TIMA channel 0 registers
initially control the pulse width on the PTE2/TACH0 pin. Writing to the
TIMA channel 1 registers enables the TIMA channel 1 registers to
synchronously control the pulse width at the beginning of the next PWM
period. At each subsequent overflow, the TIMA channel registers (0 or
1) that control the pulse width are the ones written to last. TASC0
controls and monitors the buffered PWM function and TIMA channel 1
status and control register (TASC1) is unused. While the MS0B bit is set,
the channel 1 pin, PTE3/TACH1, is available as a general-purpose I/O
pin.
Channels 2 and 3 can be linked to form a buffered PWM channel whose
output appears on the PTF0/TACH2 pin. The TIMA channel registers of
the linked pair alternately control the pulse width of the output.
Setting the MS2B bit in TIMA channel 2 status and control register
(TASC2) links channel 2 and channel 3. The TIMA channel 2 registers
initially control the pulse width on the PTF0/TACH2 pin. Writing to the
TIMA channel 3 registers enables the TIMA channel 3 registers to
synchronously control the pulse width at the beginning of the next PWM
period. At each subsequent overflow, the TIMA channel registers (2 or
3) that control the pulse width are the ones written to last. TASC2
controls and monitors the buffered PWM function and TIMA channel 3
status and control register (TASC3) is unused. While the MS2B bit is set,
the channel 3 pin, PTF1/TACH3, is available as a general-purpose I/O
pin.
Channels 4 and 5 can be linked to form a buffered PWM channel whose
output appears on the PTF2 pin. The TIMA channel registers of the
linked pair alternately control the pulse width of the output.
Setting the MS4B bit in TIMA channel 4 status and control register
(TASC4) links channel 4 and channel 5. The TIMA channel 4 registers
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Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
initially control the pulse width on the PTF2 pin. Writing to the TIMA
channel 5 registers enables the TIMA channel 5 registers to
synchronously control the pulse width at the beginning of the next PWM
period. At each subsequent overflow, the TIMA channel registers (4 or
5) that control the pulse width are the ones written to last. TASC4
controls and monitors the buffered PWM function and TIMA channel 5
status and control register (TASC5) is unused. While the MS4B bit is set,
the channel 5 pin, PTF3, is available as a general-purpose I/O pin.
NOTE:
In buffered PWM signal generation, do not write new pulse width values
to the currently active channel registers. User software should track the
currently active channel to prevent writing a new value to the active
channel. Writing to the active channel registers is the same as
generating unbuffered PWM signals.
23.4.4.3 PWM Initialization
To ensure correct operation when generating unbuffered or buffered
PWM signals, use the following initialization procedure:
1. In the TIMA status and control register (TASC):
a. Stop the TIMA counter and prescaler by setting the TIMA stop
bit, TSTOP.
b. Reset the TIMA counter and prescaler by setting the TIMA
reset bit, TRST.
2. In the TIMA counter modulo registers (TAMODH–TAMODL) write
the value for the required PWM period.
3. In the TIMA channel x registers (TACHxH–TACHxL) write the
value for the required pulse width.
4. In TIMA channel x status and control register (TASCx):
a. Write 0:1 (for unbuffered output compare or PWM signals) or
1:0 (for buffered output compare or PWM signals) to the
mode select bits, MSxB–MSxA (see Table 23-2).
b. Write 1 to the toggle-on-overflow bit, TOVx.
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Technical Data
Timer Interface Module A (TIMA)
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Timer Interface Module A (TIMA)
c. Write 1:0 (to clear output on compare) or 1:1 (to set output on
compare) to the edge/level select bits, ELSxB–ELSxA. The
output action on compare must force the output to the
complement of the pulse width level (see Table 23-2).
NOTE:
In PWM signal generation, do not program the PWM channel to toggle
on output compare. Toggling on output compare prevents reliable 0%
duty cycle generation and removes the ability of the channel to selfcorrect in the event of software error or noise. Toggling on output
compare can also cause incorrect PWM signal generation when
changing the PWM pulse width to a new, much larger value.
5. In the TIMA status control register (TASC) clear the TIMA stop bit,
TSTOP.
Setting MS0B links channels 0 and 1 and configures them for buffered
PWM operation. The TIMA channel 0 registers (TACH0H–TACH0L)
initially control the buffered PWM output. TIMA status control register 0
(TASC0) controls and monitors the PWM signal from the linked
channels. MS0B takes priority over MS0A.
Setting MS2B links channels 2 and 3 and configures them for buffered
PWM operation. The TIMA channel 2 registers (TACH2H–TACH2L)
initially control the buffered PWM output. TIMA status control register 2
(TASC2) controls and monitors the PWM signal from the linked
channels. MS2B takes priority over MS2A.
Setting MS4B links channels 4 and 5 and configures them for buffered
PWM operation. The TIMA channel 4 registers (TACH4H–TACH4L)
initially control the buffered PWM output. TIMA status control register 4
(TASC4) controls and monitors the PWM signal from the linked
channels. MS4B takes priority over MS4A.
Clearing the toggle-on-overflow bit, TOVx, inhibits output toggles on
TIMA overflows. Subsequent output compares try to force the output to
a state it is already in and have no effect. The result is a 0% duty cycle
output.
Setting the channel x maximum duty cycle bit (CHxMAX) and setting the
TOVx bit generates a 100% duty cycle output (see TIMA Channel
Status and Control Registers on page 424).
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Freescale Semiconductor
Timer Interface Module A (TIMA)
23.5 Interrupts
The following TIMA sources can generate interrupt requests:
•
TIMA overflow flag (TOF) — The TOF bit is set when the TIMA
counter reaches the modulo value programmed in the TIMA
counter modulo registers. The TIMA overflow interrupt enable bit,
TOIE, enables TIMA overflow CPU interrupt requests. TOF and
TOIE are in the TIMA status and control register.
•
TIMA channel flags (CH5F–CH0F) — The CHxF bit is set when an
input capture or output compare occurs on channel x. Channel x
TIMA CPU interrupt requests are controlled by the channel x
interrupt enable bit, CHxIE.
23.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low powerconsumption standby modes.
23.6.1 Wait Mode
The TIMA remains active after the execution of a WAIT instruction. In
wait mode, the TIMA registers are not accessible by the CPU. Any
enabled CPU interrupt request from the TIMA can bring the MCU out of
wait mode.
If TIMA functions are not required during wait mode, reduce power
consumption by stopping the TIMA before executing the WAIT
instruction.
23.6.2 Stop Mode
The TIMA is inactive after the execution of a STOP instruction. The
STOP instruction does not affect register conditions or the state of the
TIMA counter. TIMA operation resumes when the MCU exits stop mode.
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Technical Data
Timer Interface Module A (TIMA)
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Timer Interface Module A (TIMA)
23.7 TIMA During Break Interrupts
A break interrupt stops the TIMA counter and inhibits input captures.
The system integration module (SIM) controls whether status bits in
other modules can be cleared during the break state. The BCFE bit in
the SIM break flag control register (SBFCR) enables software to clear
status bits during the break state (see SIM Break Flag Control Register
(SBFCR) on page 137).
To allow software to clear status bits during a break interrupt, write a
logic 1 to the BCFE bit. If a status bit is cleared during the break state, it
remains cleared when the MCU exits the break state.
To protect status bits during the break state, write a logic 0 to the BCFE
bit. With BCFE at logic 0 (its default state), software can read and write
I/O registers during the break state without affecting status bits. Some
status bits have a 2-step read/write clearing procedure. If software does
the first step on such a bit before the break, the bit cannot change during
the break state as long as BCFE is at logic 0. After the break, doing the
second step clears the status bit.
23.8 I/O Signals
Port D shares one of its pins with the TIMA. Port E shares two of its pins
with the TIMA and port F shares four of its pins with the TIMA.
PTD6/ATD14/TACLK is an external clock input to the TIMA prescaler.
The six TIMA channel I/O pins are PTE2/TACH0, PTE3/TACH1,
PTF0/TACH2, PTF1/TACH3, PTF2, and PTF3.
23.8.1 TIMA Clock Pin (PTD6/ATD14/TACLK)
PTD6/ATD14/TACLK is an external clock input that can be the clock
source for the TIMA counter instead of the prescaled internal bus clock.
Select the PTD6/ATD14/TACLK input by writing logic 1s to the three
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Freescale Semiconductor
Timer Interface Module A (TIMA)
prescaler select bits, PS[2:0] (see TIMA Status and Control Register).
The minimum TCLK pulse width, TCLKLMIN or TCLKHMIN, is:
1
------------------------------------- + t SU
bus frequency
The maximum TCLK frequency is the least: 4 MHz or bus frequency ÷ 2.
PTD6/ATD14/TACLK is available as a general-purpose I/O pin or ADC
channel when not used as the TIMA clock input. When the
PTD6/ATD14/TACLK pin is the TIMA clock input, it is an input regardless
of the state of the DDRD6 bit in data direction register D.
23.8.2 TIMA Channel I/O Pins (PTF3–PTF0/TACH2 and PTE3/TACH1–PTE2/TACH0)
Each channel I/O pin is programmable independently as an input
capture pin or an output compare pin. PTE2/TACH0, PTF0/TACH2 and
PTF2 can be configured as buffered output compare or buffered PWM
pins.
23.9 I/O Registers
These I/O registers control and monitor TIMA operation:
•
TIMA status and control register (TASC)
•
TIMA control registers (TACNTH–TACNTL)
•
TIMA counter modulo registers (TAMODH–TAMODL)
•
TIMA channel status and control registers (TASC0, TASC1,
TASC2, TASC3, TASC4 and TASC5)
•
TIMA channel registers (TACH0H–TACH0L, TACH1H–TACH1L,
TACH2H–TACH2L, TACH3H–TACH3L, TACH4H–TACH4L and
TACH5H–TACH5L)
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Technical Data
Timer Interface Module A (TIMA)
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Timer Interface Module A (TIMA)
23.9.1 TIMA Status and Control Register
The TIMA status and control register:
•
Enables TIMA overflow interrupts
•
Flags TIMA overflows
•
Stops the TIMA counter
•
Resets the TIMA counter
•
Prescales the TIMA counter clock
Address:
$0020
Bit 7
Read:
TOF
Write:
0
Reset:
0
R
6
5
TOIE
TSTOP
0
1
4
3
0
0
TRST
R
0
0
2
1
Bit 0
PS2
PS1
PS0
0
0
0
= Reserved
Figure 23-4. TIMA Status and Control Register (TASC)
TOF — TIMA Overflow Flag Bit
This read/write flag is set when the TIMA counter reaches the modulo
value programmed in the TIMA counter modulo registers. Clear TOF
by reading the TIMA status and control register when TOF is set and
then writing a logic 0 to TOF. If another TIMA overflow occurs before
the clearing sequence is complete, then writing logic 0 to TOF has no
effect. Therefore, a TOF interrupt request cannot be lost due to
inadvertent clearing of TOF. Reset clears the TOF bit. Writing a logic
1 to TOF has no effect.
1 = TIMA counter has reached modulo value.
0 = TIMA counter has not reached modulo value.
TOIE — TIMA Overflow Interrupt Enable Bit
This read/write bit enables TIMA overflow interrupts when the TOF bit
becomes set. Reset clears the TOIE bit.
1 = TIMA overflow interrupts enabled
0 = TIMA overflow interrupts disabled
Technical Data
420
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
TSTOP — TIMA Stop Bit
This read/write bit stops the TIMA counter. Counting resumes when
TSTOP is cleared. Reset sets the TSTOP bit, stopping the TIMA
counter until software clears the TSTOP bit.
1 = TIMA counter stopped
0 = TIMA counter active
NOTE:
Do not set the TSTOP bit before entering wait mode if the TIMA is
required to exit wait mode. Also, when the TSTOP bit is set and input
capture mode is enabled, input captures are inhibited until TSTOP is
cleared.
TRST — TIMA Reset Bit
Setting this write-only bit resets the TIMA counter and the TIMA
prescaler. Setting TRST has no effect on any other registers.
Counting resumes from $0000. TRST is cleared automatically after
the TIMA counter is reset and always reads as logic 0. Reset clears
the TRST bit.
1 = Prescaler and TIMA counter cleared
0 = No effect
NOTE:
Setting the TSTOP and TRST bits simultaneously stops the TIMA
counter at a value of $0000.
PS[2:0] — Prescaler Select Bits
These read/write bits select either the PTD6/ATD14/TACLK pin or
one of the seven prescaler outputs as the input to the TIMA counter
as Table 23-1 shows. Reset clears the PS[2:0] bits.
Table 23-1. Prescaler Selection
PS[2:0]
TIMA Clock Source
000
Internal Bus Clock ÷1
001
Internal Bus Clock ÷ 2
010
Internal Bus Clock ÷ 4
011
Internal Bus Clock ÷ 8
100
Internal Bus Clock ÷ 16
101
Internal Bus Clock ÷ 32
110
Internal Bus Clock ÷ 64
111
PTD6/ATD14/TACLK
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
421
Timer Interface Module A (TIMA)
23.9.2 TIMA Counter Registers
The two read-only TIMA counter registers contain the high and low bytes
of the value in the TIMA counter. Reading the high byte (TACNTH)
latches the contents of the low byte (TACNTL) into a buffer. Subsequent
reads of TACNTH do not affect the latched TACNTL value until TACNTL
is read. Reset clears the TIMA counter registers. Setting the TIMA reset
bit (TRST) also clears the TIMA counter registers.
NOTE:
If TACNTH is read during a break interrupt, be sure to unlatch TACNTL
by reading TACNTL before exiting the break interrupt. Otherwise,
TACNTL retains the value latched during the break.
Register Name and Address TACNTH — $0022
Bit 7
6
5
4
3
2
1
Bit 0
Read:
BIT 15
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
Write:
R
R
R
R
R
R
R
R
Reset:
0
0
0
0
0
0
0
0
Register Name and Address TACNTL — $0023
Bit 7
6
5
4
3
2
1
Bit 0
Read:
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Write:
R
R
R
R
R
R
R
R
Reset:
0
0
0
0
0
0
0
0
R
= Reserved
Figure 23-5. TIMA Counter Registers (TACNTH and TACNTL)
Technical Data
422
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
23.9.3 TIMA Counter Modulo Registers
The read/write TIMA modulo registers contain the modulo value for the
TIMA counter. When the TIMA counter reaches the modulo value, the
overflow flag (TOF) becomes set and the TIMA counter resumes
counting from $0000 at the next timer clock. Writing to the high byte
(TAMODH) inhibits the TOF bit and overflow interrupts until the low byte
(TAMODL) is written. Reset sets the TIMA counter modulo registers.
Register Name and Address TAMODH — $0024
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
BIT 15
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
1
1
1
1
1
1
1
1
Register Name and Address TAMODL — $0025
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
1
1
1
1
1
1
1
1
Figure 23-6. TIMA Counter Modulo Registers (TAMODH and
TAMODL)
NOTE:
Reset the TIMA counter before writing to the TIMA counter modulo
registers.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
423
Timer Interface Module A (TIMA)
23.9.4 TIMA Channel Status and Control Registers
Each of the TIMA channel status and control registers:
•
Flags input captures and output compares
•
Enables input capture and output compare interrupts
•
Selects input capture, output compare or PWM operation
•
Selects high, low or toggling output on output compare
•
Selects rising edge, falling edge or any edge as the active input
capture trigger
•
Selects output toggling on TIMA overflow
•
Selects 0% and 100% PWM duty cycle
•
Selects buffered or unbuffered output compare/PWM operation
Technical Data
424
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
Register Name and Address TASC0 — $0026
Bit 7
Read:
CH0F
Write:
0
Reset:
0
6
5
4
3
2
1
Bit 0
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
0
0
0
0
0
0
0
4
3
2
1
Bit 0
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
0
0
0
0
0
Register Name and Address TASC1 — $0029
Bit 7
Read:
CH1F
Write:
0
Reset:
0
R
6
CH1IE
0
5
0
R
0
= Reserved
Register Name and Address TASC2 — $002C
Bit 7
Read:
CH2F
Write:
0
Reset:
0
6
5
4
3
2
1
Bit 0
CH2IE
MS2B
MS2A
ELS2B
ELS2A
TOV2
CH2MAX
0
0
0
0
0
0
0
4
3
2
1
Bit 0
MS3A
ELS3B
ELS3A
TOV3
CH3MAX
0
0
0
0
0
Register Name and Address TASC3 — $002F
Bit 7
Read:
CH3F
Write:
0
Reset:
0
6
CH3IE
0
5
0
R
0
Register Name and Address TASC4 — $0032
Bit 7
Read:
CH4F
Write:
0
Reset:
0
6
5
4
3
2
1
Bit 0
CH4IE
MS4B
MS4A
ELS4B
ELS4A
TOV4
CH4MAX
0
0
0
0
0
0
0
4
3
2
1
Bit 0
MS5A
ELS5B
ELS5A
TOV5
CH5MAX
0
0
0
0
0
Register Name and Address TASC5 — $0035
Bit 7
Read:
CH5F
Write:
0
Reset:
0
R
6
CH5IE
0
5
0
R
0
= Reserved
Figure 23-7. TIMA Channel Status and Control Registers (TASC0–TASC5)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
425
Timer Interface Module A (TIMA)
CHxF — Channel x Flag Bit
When channel x is an input capture channel, this read/write bit is set
when an active edge occurs on the channel x pin. When channel x is
an output compare channel, CHxF is set when the value in the TIMA
counter registers matches the value in the TIMA channel x registers.
When CHxIE = 1, clear CHxF by reading TIMA channel x status and
control register with CHxF set and then writing a logic 0 to CHxF. If
another interrupt request occurs before the clearing sequence is
complete, then writing logic 0 to CHxF has no effect. Therefore, an
interrupt request cannot be lost due to inadvertent clearing of CHxF.
Reset clears the CHxF bit. Writing a logic 1 to CHxF has no effect.
1 = Input capture or output compare on channel x
0 = No input capture or output compare on channel x
CHxIE — Channel x Interrupt Enable Bit
This read/write bit enables TIMA CPU interrupts on channel x.
Reset clears the CHxIE bit.
1 = Channel x CPU interrupt requests enabled
0 = Channel x CPU interrupt requests disabled
MSxB — Mode Select Bit B
This read/write bit selects buffered output compare/PWM operation.
MSxB exists only in the TIMA channel 0, TIMA channel 2 and TIMA
channel 4 status and control registers.
Setting MS0B disables the channel 1 status and control register and
reverts TACH1 pin to general-purpose I/O.
Setting MS2B disables the channel 3 status and control register and
reverts TACH3 pin to general-purpose I/O.
Setting MS4B disables the channel 5 status and control register and
reverts TACH5 pin to general-purpose I/O.
Reset clears the MSxB bit.
1 = Buffered output compare/PWM operation enabled
0 = Buffered output compare/PWM operation disabled
Technical Data
426
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
MSxA — Mode Select Bit A
When ELSxB:A ≠ 00, this read/write bit selects either input capture
operation or unbuffered output compare/PWM operation. See Table
23-2.
1 = Unbuffered output compare/PWM operation
0 = Input capture operation
When ELSxB:A = 00, this read/write bit selects the initial output level
of the TACHx pin once PWM, output compare mode or input capture
mode is enabled. See Table 23-2. Reset clears the MSxA bit.
1 = Initial output level low
0 = Initial output level high
NOTE:
Before changing a channel function by writing to the MSxB or MSxA bit,
set the TSTOP and TRST bits in the TIMA status and control register
(TASC).
ELSxB and ELSxA — Edge/Level Select Bits
When channel x is an input capture channel, these read/write bits
control the active edge-sensing logic on channel x.
When channel x is an output compare channel, ELSxB and ELSxA
control the channel x output behavior when an output compare
occurs.
When ELSxB and ELSxA are both clear, channel x is not connected
to port E or port F and pin PTEx/TACHx or pin PTFx/TACHx is
available as a general-purpose I/O pin. However, channel x is at a
state determined by these bits and becomes transparent to the
respective pin when PWM, input capture mode or output compare
operation mode is enabled. Table 23-2 shows how ELSxB and
ELSxA work. Reset clears the ELSxB and ELSxA bits.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
427
Timer Interface Module A (TIMA)
Table 23-2. Mode, Edge, and Level Selection
MSxB:MSxA
ELSxB:ELSxA
X0
00
Mode
Output
Preset
NOTE:
X1
00
00
01
00
10
00
11
01
01
01
10
01
11
1X
01
1X
10
1X
11
Configuration
Pin under Port Control;
Initialize Timer
Output Level High
Pin under Port Control;
Initialize Timer
Output Level Low
Capture on Rising Edge Only
Input
Capture
Capture on Falling Edge Only
Capture on Rising or Falling Edge
Output
Compare
or PWM
Buffered
Output
Compare
or Buffered
PWM
Toggle Output on Compare
Clear Output on Compare
Set Output on Compare
Toggle Output on Compare
Clear Output on Compare
Set Output on Compare
Before enabling a TIMA channel register for input capture operation,
make sure that the PTEx/TACHx pin or PTFx/TACHx pin is stable for at
least two bus clocks.
TOVx — Toggle-On-Overflow Bit
When channel x is an output compare channel, this read/write bit
controls the behavior of the channel x output when the TIMA counter
overflows. When channel x is an input capture channel, TOVx has no
effect. Reset clears the TOVx bit.
1 = Channel x pin toggles on TIMA counter overflow.
0 = Channel x pin does not toggle on TIMA counter overflow.
NOTE:
When TOVx is set, a TIMA counter overflow takes precedence over a
channel x output compare if both occur at the same time.
Technical Data
428
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
CHxMAX — Channel x Maximum Duty Cycle Bit
When the TOVx bit is at logic 1, setting the CHxMAX bit forces the
duty cycle of buffered and unbuffered PWM signals to 100%. As
Figure 23-8 shows, the CHxMAX bit takes effect in the cycle after it
is set or cleared. The output stays at the 100% duty cycle level until
the cycle after CHxMAX is cleared.
OVERFLOW
OVERFLOW
OVERFLOW
OVERFLOW
OVERFLOW
PERIOD
PTEx/TCHx
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
OUTPUT
COMPARE
CHxMAX
Figure 23-8. CHxMAX Latency
23.9.5 TIMA Channel Registers
These read/write registers contain the captured TIMA counter value of
the input capture function or the output compare value of the output
compare function. The state of the TIMA channel registers after reset is
unknown.
In input capture mode (MSxB–MSxA = 0:0) reading the high byte of the
TIMA channel x registers (TACHxH) inhibits input captures until the low
byte (TACHxL) is read.
In output compare mode (MSxB–MSxA ≠ 0:0) writing to the high byte of
the TIMA channel x registers (TACHxH) inhibits output compares and
the CHxF bit until the low byte (TACHxL) is written.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
429
Timer Interface Module A (TIMA)
Register Name and Address TACH0H — $0027
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TACH0L — $0028
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset:
Indeterminate after Reset
Register Name and Address TACH1H — $002A
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TACH1L — $002B
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset:
Indeterminate after Reset
Register Name and Address TACH2H — $002D
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TACH2L — $002E
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Indeterminate after Reset
Figure 23-9. TIMA Channel Registers (TACH0H/L–TACH5H/L) (Sheet
1 of 2)
Technical Data
430
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Timer Interface Module A (TIMA)
Register Name and Address TACH3H — $0030
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TACH3L — $0031
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset:
Indeterminate after Reset
Register Name and Address TACH4H — $0033
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TACH4L — $0034
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset:
Indeterminate after Reset
Register Name and Address TACH5H — $0036
Read:
Write:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Reset:
Indeterminate after Reset
Register Name and Address TACH5L — $0037
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Indeterminate after Reset
Figure 23-9. TIMA Channel Registers (TACH0H/L–TACH5H/L) (Sheet
2 of 2)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Timer Interface Module A (TIMA)
431
Timer Interface Module A (TIMA)
Technical Data
432
MC68HC08AZ60A — Rev 2.1
Timer Interface Module A (TIMA)
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 24. Analog-to-Digital Converter (ADC-15)
24.1 Contents
24.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
24.3
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .434
24.4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
24.4.1 ADC Port I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
24.4.2 Voltage Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
24.4.3 Conversion Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
24.4.4 Continuous Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . 437
24.4.5 Accuracy and Precision. . . . . . . . . . . . . . . . . . . . . . . . . . 437
24.5
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
24.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
24.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
24.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
24.7 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
24.7.1 ADC Analog Power Pin (VDDAREF) . . . . . . . . . . . . . . . . 438
24.7.2 ADC Analog Ground/ADC Voltage Reference Low Pin
(AVSS/VREFL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
24.7.4 ADC Voltage In (ADCVIN) . . . . . . . . . . . . . . . . . . . . . . . . 439
24.8 I/O Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .439
24.8.1 ADC Status and Control Register . . . . . . . . . . . . . . . . . . 439
24.8.2 ADC Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
24.8.3 ADC Input Clock Register . . . . . . . . . . . . . . . . . . . . . . . . 442
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Analog-to-Digital Converter (ADC-15)
433
Analog-to-Digital Converter (ADC-15)
24.2 Introduction
This section describes the analog-to-digital converter. The ADC is an 8bit analog-to-digital converter.
For further information regarding analog-to-digital converters on
Freescale microcontrollers, please consult the HC08 ADC Reference
Manual, ADCRM/AD.
24.3 Features
Features of the ADC module include:
•
15 Channels with Multiplexed Input
•
Linear Successive Approximation
•
8-Bit Resolution
•
Single or Continuous Conversion
•
Conversion Complete Flag or Conversion Complete Interrupt
•
Selectable ADC Clock
24.4 Functional Description
Fifteen ADC channels are available for sampling external sources at
pins PTD6/ATD14/TACLK–PTD0/ATD8 and PTB7/ATD7–PTB0/ATD0.
An analog multiplexer allows the single ADC converter to select one of
15 ADC channels as ADC voltage in (ADCVIN). ADCVIN is converted by
the successive approximation register-based counters. When the
conversion is completed, ADC places the result in the ADC data register
and sets a flag or generates an interrupt. See Figure 24-1.
Technical Data
434
MC68HC08AZ60A — Rev 2.1
Analog-to-Digital Converter (ADC-15)
Freescale Semiconductor
Analog-to-Digital Converter (ADC-15)
INTERNAL
DATA BUS
READ DDRB/DDRB
WRITE DDRB/DDRD
RESET
WRITE PTB/PTD
DISABLE
DDRBx/DDRDx
PTBx/PTDx
PTBx/PTDx
ADC CHANNEL x
READ PTB/PTD
DISABLE
ADC DATA REGISTER
INTERRUPT
LOGIC
AIEN
CONVERSION
COMPLETE
ADC VOLTAGE IN
ADCVIN
ADC
CHANNEL
SELECT
ADCH[4:0]
COCO
ADC CLOCK
CGMXCLK
BUS CLOCK
CLOCK
GENERATOR
ADIV[2:0]
ADICLK
Figure 24-1. ADC Block Diagram
24.4.1 ADC Port I/O Pins
PTD6/ATD14/TACLK–PTD0/ATD8 and PTB7/ATD7–PTB0/ATD0 are
general-purpose I/O pins that share with the ADC channels.
The channel select bits define which ADC channel/port pin will be used
as the input signal. The ADC overrides the port I/O logic by forcing that
pin as input to the ADC. The remaining ADC channels/port pins are
controlled by the port I/O logic and can be used as general-purpose I/O.
Writes to the port register or DDR will not have any affect on the port pin
that is selected by the ADC. Read of a port pin which is in use by the
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Analog-to-Digital Converter (ADC-15)
435
Analog-to-Digital Converter (ADC-15)
ADC will return a logic 0 if the corresponding DDR bit is at logic 0. If the
DDR bit is at logic 1, the value in the port data latch is read.
NOTE:
Do not use ADC channels ATD14 or ATD12 when using the
PTD6/ATD14/TACLK or PTD4/ATD12/TBCLK pins as the clock inputs
for the 16-bit Timers.
24.4.2 Voltage Conversion
When the input voltage to the ADC equals VREFH (see Electrical
Specifications on page 445), the ADC converts the signal to $FF (full
scale). If the input voltage equals AVSS/VREFL, the ADC converts it to
$00. Input voltages between VREFH and AVSS/VREFL are a straight-line
linear conversion. Conversion accuracy of all other input voltages is not
guaranteed. Avoid current injection on unused ADC inputs to prevent
potential conversion error.
NOTE:
Input voltage should not exceed the analog supply voltages.
24.4.3 Conversion Time
Conversion starts after a write to the ADSCR (ADC status control
register, $0038), and requires between 16 and 17 ADC clock cycles to
complete. Conversion time in terms of the number of bus cycles is a
function of ADICLK select, CGMXCLK frequency, bus frequency, and
ADIV prescaler bits. For example, with a CGMXCLK frequency of 4
MHz, bus frequency of 8 MHz, and fixed ADC clock frequency of 1 MHz,
one conversion will take between 16 and 17 µs and there will be between
128 bus cycles between each conversion. Sample rate is approximately
60 kHz.
Refer to Electrical Specifications on page 445.
16 to 17 ADC Clock Cycles
Conversion Time = 
ADC Clock Frequency
Number of Bus Cycles = Conversion Time x Bus Frequency
Technical Data
436
MC68HC08AZ60A — Rev 2.1
Analog-to-Digital Converter (ADC-15)
Freescale Semiconductor
Analog-to-Digital Converter (ADC-15)
24.4.4 Continuous Conversion
In the continuous conversion mode, the ADC data register will be filled
with new data after each conversion. Data from the previous conversion
will be overwritten whether that data has been read or not. Conversions
will continue until the ADCO bit (ADC status control register, $0038) is
cleared. The COCO bit is set after the first conversion and will stay set
for the next several conversions until the next write of the ADC status
and control register or the next read of the ADC data register.
24.4.5 Accuracy and Precision
The conversion process is monotonic and has no missing codes. See
Electrical Specifications on page 445 for accuracy information.
24.5 Interrupts
When the AIEN bit is set, the ADC module is capable of generating a
CPU interrupt after each ADC conversion. A CPU interrupt is generated
if the COCO bit (ADC status control register, $0038) is at logic 0. If the
COCO bit is set, an interrupt is generated. The COCO bit is not used as
a conversion complete flag when interrupts are enabled.
24.6 Low-Power Modes
The following subsections describe the low-power modes.
24.6.1 Wait Mode
The ADC continues normal operation during wait mode. Any enabled
CPU interrupt request from the ADC can bring the MCU out of wait
mode. If the ADC is not required to bring the MCU out of wait mode,
power down the ADC by setting the ADCH[4:0] bits in the ADC status
and control register before executing the WAIT instruction.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Analog-to-Digital Converter (ADC-15)
437
Analog-to-Digital Converter (ADC-15)
24.6.2 Stop Mode
The ADC module is inactive after the execution of a STOP instruction.
Any pending conversion is aborted. ADC conversions resume when the
MCU exits stop mode. Allow one conversion cycle to stabilize the analog
circuitry before attempting a new ADC conversion after exiting stop
mode.
24.7 I/O Signals
The ADC module has 15 channels that are shared with I/O ports B and
D. Refer to Electrical Specifications on page 445 for voltages
referenced below.
24.7.1 ADC Analog Power Pin (VDDAREF)
The ADC analog portion uses VDDAREF as its power pin. Connect the
VDDAREF pin to the same voltage potential as VDD. External filtering may
be necessary to ensure clean VDDAREF for good results.
NOTE:
Route VDDAREF carefully for maximum noise immunity and place bypass
capacitors as close as possible to the package. VDDAREF must be
present for operation of the ADC.
24.7.2 ADC Analog Ground/ADC Voltage Reference Low Pin (AVSS/VREFL)
The ADC analog portion uses AVSS/VREFL as its ground pin. Connect
the AVSS/VREFL pin to the same voltage potential as VSS.
VREFL is the lower reference supply for the ADC.
24.7.3 ADC Voltage Reference Pin (VREFH)
VREFH is the high reference voltage for all analog-to-digital conversions.
Technical Data
438
MC68HC08AZ60A — Rev 2.1
Analog-to-Digital Converter (ADC-15)
Freescale Semiconductor
Analog-to-Digital Converter (ADC-15)
24.7.4 ADC Voltage In (ADCVIN)
ADCVIN is the input voltage signal from one of the 15 ADC channels to
the ADC module.
24.8 I/O Registers
These I/O registers control and monitor ADC operation:
•
ADC status and control register (ADSCR)
•
ADC data register (ADR)
•
ADC clock register (ADICLK)
24.8.1 ADC Status and Control Register
The following paragraphs describe the function of the ADC status and
control register.
Address:
$0038
Bit 7
Read:
COCO
Write:
R
Reset:
0
R
6
5
4
3
2
1
Bit 0
AIEN
ADCO
ADCH4
ADCH3
ADCH2
ADCH1
ADCH0
0
0
1
1
1
1
1
= Reserved
Figure 24-2. ADC Status and Control Register (ADSCR)
COCO — Conversions Complete Bit
When the AIEN bit is a logic 0, the COCO is a read-only bit which is
set each time a conversion is completed. This bit is cleared whenever
the ADC status and control register is written or whenever the ADC
data register is read.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Analog-to-Digital Converter (ADC-15)
439
Analog-to-Digital Converter (ADC-15)
If the AIEN bit is a logic 1, the COCO is a read/write bit which selects
the CPU to service the ADC interrupt request. Reset clears this bit.
1 = conversion completed (AIEN = 0)
0 = conversion not completed (AIEN = 0)
or
CPU interrupt enabled (AIEN = 1)
AIEN — ADC Interrupt Enable Bit
When this bit is set, an interrupt is generated at the end of an ADC
conversion. The interrupt signal is cleared when the data register is
read or the status/control register is written. Reset clears the AIEN bit.
1 = ADC interrupt enabled
0 = ADC interrupt disabled
ADCO — ADC Continuous Conversion Bit
When set, the ADC will convert samples continuously and update the
ADR register at the end of each conversion. Only one conversion is
allowed when this bit is cleared. Reset clears the ADCO bit.
1 = Continuous ADC conversion
0 = One ADC conversion
ADCH[4:0] — ADC Channel Select Bits
ADCH4, ADCH3, ADCH2, ADCH1, and ADCH0 form a 5-bit field
which is used to select one of 15 ADC channels. Channel selection is
detailed in the following table. Care should be taken when using a port
pin as both an analog and a digital input simultaneously to prevent
switching noise from corrupting the analog signal. See Table 24-1.
The ADC subsystem is turned off when the channel select bits are all
set to one. This feature allows for reduced power consumption for the
MCU when the ADC is not used. Reset sets these bits.
NOTE:
Recovery from the disabled state requires one conversion cycle to
stabilize.
Technical Data
440
MC68HC08AZ60A — Rev 2.1
Analog-to-Digital Converter (ADC-15)
Freescale Semiconductor
Analog-to-Digital Converter (ADC-15)
Table 24-1. Mux Channel Select
ADCH4
ADCH3
ADCH2
ADCH1
ADCH0
Input Select
0
0
0
0
0
PTB0/ATD0
0
0
0
0
1
PTB1/ATD1
0
0
0
1
0
PTB2/ATD2
0
0
0
1
1
PTB3/ATD3
0
0
1
0
0
PTB4/ATD4
0
0
1
0
1
PTB5/ATD5
0
0
1
1
0
PTB6/ATD6
0
0
1
1
1
PTB7/ATD7
0
1
0
0
0
PTD0/ATD8
0
1
0
0
1
PTD1/ATD9
0
1
0
1
0
PTD2/ATD10
0
1
0
1
1
PTD3/ATD11
0
1
1
0
0
PTD4/ATD12/TBCLK
0
1
1
0
1
PTD5/ATD13
0
1
1
1
0
PTD6/ATD14/TACLK
Unused (see Note 1)
Range 01111 ($0F) to 11010 ($1A)
Unused (see Note 1)
1
1
0
1
1
Reserved
1
1
1
0
0
Unused (see Note 1)
1
1
1
0
1
VREFH
(see Note 2)
1
1
1
1
0
AVSS/VREFL (see Note 2)
1
1
1
1
1
[ADC power off]
NOTES:
1. If any unused channels are selected, the resulting ADC conversion will be
unknown.
2. The voltage levels supplied from internal reference nodes as specified in the
table are used to verify the operation of the ADC converter both in production
test and for user applications.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Analog-to-Digital Converter (ADC-15)
441
Analog-to-Digital Converter (ADC-15)
24.8.2 ADC Data Register
One 8-bit result register is provided. This register is updated each time
an ADC conversion completes.
Address:
$0039
Bit 7
6
5
4
3
2
1
Bit 0
Read:
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
Write:
R
R
R
R
R
R
R
R
Reset:
Indeterminate after Reset
R
= Reserved
Figure 24-3. ADC Data Register (ADR)
24.8.3 ADC Input Clock Register
This register selects the clock frequency for the ADC.
Address:
Read:
Write:
Reset:
$003A
Bit 7
6
5
4
ADIV2
ADIV1
ADIV0
ADICLK
0
0
0
0
R
3
2
1
Bit 0
0
0
0
0
R
R
R
R
0
0
0
0
= Reserved
Figure 24-4. ADC Input Clock Register (ADICLK)
ADIV2–ADIV0 — ADC Clock Prescaler Bits
ADIV2, ADIV1, and ADIV0 form a 3-bit field which selects the divide
ratio used by the ADC to generate the internal ADC clock. Table 242 shows the available clock configurations. The ADC clock should be
set to approximately 1 MHz.
Technical Data
442
MC68HC08AZ60A — Rev 2.1
Analog-to-Digital Converter (ADC-15)
Freescale Semiconductor
Analog-to-Digital Converter (ADC-15)
Table 24-2. ADC Clock Divide Ratio
ADIV2
ADIV1
ADIV0
ADC Clock Rate
0
0
0
ADC Input Clock /1
0
0
1
ADC Input Clock / 2
0
1
0
ADC Input Clock / 4
0
1
1
ADC Input Clock / 8
1
X
X
ADC Input Clock / 16
X = don’t care
ADICLK — ADC Input Clock Register Bit
ADICLK selects either bus clock or CGMXCLK as the input clock
source to generate the internal ADC clock. Reset selects CGMXCLK
as the ADC clock source.
If the external clock (CGMXCLK) is equal to or greater than 1 MHz,
CGMXCLK can be used as the clock source for the ADC. If
CGMXCLK is less than 1 MHz, use the PLL-generated bus clock as
the clock source. As long as the internal ADC clock is at
approximately 1 MHz, correct operation can be guaranteed. See
Electrical Specifications on page 445.
1 = Internal bus clock
0 = External clock (CGMXCLK)
fXCLK or Bus Frequency
1 MHz = 
ADIV[2:0]
NOTE:
During the conversion process, changing the ADC clock will result in an
incorrect conversion.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Analog-to-Digital Converter (ADC-15)
443
Analog-to-Digital Converter (ADC-15)
Technical Data
444
MC68HC08AZ60A — Rev 2.1
Analog-to-Digital Converter (ADC-15)
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 25. Electrical Specifications
25.1 Contents
25.2
Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
25.3
Functional Operating Range . . . . . . . . . . . . . . . . . . . . . . . . 447
25.4
Thermal Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
25.5
5.0 Volt DC Electrical Characteristics. . . . . . . . . . . . . . . . . 448
25.6
Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
25.7
ADC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
25.8
5.0 Vdc ± 0.5 V Serial Peripheral Interface (SPI) Timing . . 451
25.9
CGM Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 454
25.10 CGM Component Information . . . . . . . . . . . . . . . . . . . . . . .454
25.11 CGM Acquisition/Lock Time Information . . . . . . . . . . . . . . 455
25.12 RAM Memory Characteristics . . . . . . . . . . . . . . . . . . . . . . .456
25.13 EEPROM Memory Characteristics . . . . . . . . . . . . . . . . . . . 456
25.14 Mechanical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 457
25.14.1 64-pin Quad Flat Pack (QFP) . . . . . . . . . . . . . . . . . . . . . . 457
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Electrical Specifications
445
Electrical Specifications
25.2 Maximum Ratings
Maximum ratings are the extreme limits to which the MCU can be
exposed without permanently damaging it.
NOTE:
This device is not guaranteed to operate at the maximum ratings. Refer
to 5.0 Volt DC Electrical Characteristics for guaranteed operating
conditions.
Rating
Symbol
Value
Unit
Supply Voltage
VDD
–0.3 to +6.0
V
Input Voltage
VIN
VSS –0.3 to VDD +0.3
V
I
± 25
mA
Storage Temperature
TSTG
–55 to +150
°C
Maximum Current out of VSS
IMVSS
100
mA
Maximum Current into VDD
IMVDD
100
mA
VHI
VDD + 4.0
V
Maximum Current Per Pin
Excluding VDD and VSS
Reset and IRQ Input Voltage
NOTE: Voltages are referenced to VSS.
NOTE:
This device contains circuitry to protect the inputs against damage due
to high static voltages or electric fields; however, it is advised that normal
precautions be taken to avoid application of any voltage higher than
maximum-rated voltages to this high-impedance circuit. For proper
operation, it is recommended that VIN and VOUT be constrained to the
range VSS ≤ (VIN or VOUT) ≤ VDD. Reliability of operation is enhanced if
unused inputs are connected to an appropriate logic voltage level (for
example, either VSS or VDD).
Technical Data
446
MC68HC08AZ60A — Rev 2.1
Electrical Specifications
Freescale Semiconductor
Electrical Specifications
25.3 Functional Operating Range
Rating
Symbol
Value
Unit
TA
–40 to TA (max)
°C
VDD
5.0 ± 0.5v
V
Operating Temperature Range(1)
Operating Voltage Range
1. TA (MAX) = 125°C for part suffix MFU
105°C for part suffix VFU
85°C for part suffix CFU
NOTE:
For applications which use the LVI, Freescale guarantee the
functionality of the device down to the LVI trip point (VLVI) within the
constraints outlined in Low Voltage Inhibit (LVI) on page 195.
25.4 Thermal Characteristics
Characteristic
Symbol
Value
Unit
Thermal Resistance
QFP (64 Pins)
θJA
70
°C/W
I/O Pin Power Dissipation
PI/O
User Determined
W
Power Dissipation (see Note 1)
PD
PD = (IDD x VDD) +
PI/O = K/(TJ + 273 °C
W
Constant (see Note 2)
K
Average Junction Temperature
TJ
PD x (TA + 273 °C)
+ (PD2 x θJA)
TA = PD
x θJA
W/°C
°C
NOTES:
1. Power dissipation is a function of temperature.
2. K is a constant unique to the device. K can be determined from a known TA and measured
PD. With this value of K, PD, and TJ can be determined for any value of TA.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Electrical Specifications
447
Electrical Specifications
25.5 5.0 Volt DC Electrical Characteristics
Characteristic
Symbol
Min
Max
Unit
VDD –0.8
—
V
VDD –1.5
—
V
—
10
mA
—
0.4
V
—
1.5
V
IOL(TOT)
—
15
mA
Input High Voltage
All Ports, IRQs, RESET, OSC1
VIH
0.7 x VDD
VDD
V
Input Low Voltage
All Ports, IRQs, RESET, OSC1
VIL
VSS
0.3 x VDD
V
—
—
35
20
mA
mA
—
—
—
—
50
100
400
500
µA
µA
µA
µA
Output High Voltage
(ILOAD = –2.0 mA) All Ports
(ILOAD = –5.0 mA) All Ports
VOH
IOH(TOT)
Total source current
Output Low Voltage
(ILOAD = 1.6 mA) All Ports
(ILOAD = 10.0 mA) All Ports
Total sink current
VDD + VDDA Supply Current
Run (see Note 2)(see Note 9)
Wait (see Note 3)(see Note 9)
Stop (see Note 4)
25 °C
–40 °C to +125 °C
25 °C with LVI Enabled
–40 °C to +125 °C with LVI Enabled
VOL
IDD
I/O Ports Hi-Z Leakage Current
IL
–1
1
µA
Input Current
IIN
–1
1
µA
COUT
CIN
—
—
12
8
pF
Capacitance
Ports (As Input or Output)
Low-Voltage Reset Inhibit
(trip)
(recover)
VLVI
3.80
4.49
V
POR ReArm Voltage (see Note 5)
VPOR
0
200
mV
POR Reset Voltage (see Note 6)
VPORRST
0
800
mV
RPOR
0.02
—
V/ms
VHI
VDD + 3.0
VDD + 4.5
V
POR Rise Time Ramp Rate (see Note 7)
High COP Disable Voltage (see Note 8)
Technical Data
448
MC68HC08AZ60A — Rev 2.1
Electrical Specifications
Freescale Semiconductor
Electrical Specifications
Monitor Mode Entry Voltage on IRQ
(see Note 10)
VHI
VDD + 3.0
VDD + 4.5
V
1.VDD = 5.0 Vdc ± 0.5v, VSS = 0 Vdc, TA = –40 °C to TA (MAX), unless otherwise noted.
2.Run (Operating) IDD measured using external square wave clock source (fBUS = 8.4 MHz). All inputs 0.2 V from rail.
No dc loads. Less than 100 pF on all outputs. CL = 20 pF on OSC2. All ports configured as inputs. OSC2 capacitance linearly affects run IDD. Measured with all modules enabled.
3.Wait IDD measured using external square wave clock source (fBUS = 8.4 MHz). All inputs 0.2 Vdc from rail. No dc
loads. Less than 100 pF on all outputs, CL = 20 pF on OSC2. All ports configured as inputs. OSC2 capacitance
linearly affects wait IDD. Measured with all modules enabled.
4.Stop IDD measured with OSC1 = VSS.
5.Maximum is highest voltage that POR is guaranteed.
6.Maximum is highest voltage that POR is possible.
7.If minimum VDD is not reached before the internal POR reset is released, RST must be driven low externally until
minimum VDD is reached.
8.See Computer Operating Properly (COP) on page 189. VHI applied to RST.
9.Although IDD is proportional to bus frequency, a current of several mA is present even at very low frequencies.
10.See monitor mode description within Computer Operating Properly (COP) on page 189. VHI applied to IRQ or RST.
25.6 Control Timing
Characteristic
Symbol
Min
Max
Unit
Bus Operating Frequency (4.5–5.5 V — VDD Only)
fBUS
—
8.4
MHz
Internal Clock Period (1/fBUS)
tcyc
119
—
ns
RESET Pulse Width Low
tRL
1.5
—
tcyc
IRQ Interrupt Pulse Width Low (Edge-Triggered)
tILHI
1.5
—
tcyc
IRQ Interrupt Pulse Period
tILIL
Note 3
—
tcyc
tTH, tTL
tTLTL
tTCH, tTCL
2
Note 3
(1/fOP) + 5
—
—
—
tcyc
tcyc
ns
tWUP
2
5
µs
16-Bit Timer
Input Capture Pulse Width (see Note 2)
Input Capture Period
Input Clock Pulse Width
MSCAN Wake-up Filter Pulse Width (see Note 4)
1.VDD = 5.0 Vdc ± 0.5v, VSS = 0 Vdc, TA = –40 °C to TA (MAX), unless otherwise noted.
2.Refer to Table 18-2 and Table 23-2 and supporting notes.
3.The minimum period tTLTL or tILIL should not be less than the number of cycles it takes to execute the capture interrupt
service routine plus tcyc.
4. The minimum pulse width to wake up the MSCAN module is guaranteed by design but not tested.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Electrical Specifications
449
Electrical Specifications
25.7 ADC Characteristics
Characteristic
Min
Max
Unit
Resolution
8
8
Bits
Absolute Accuracy
(VREFL = 0 V, VDDA = VREFH = 5 V ± 0.5v)
–1
+1
LSB
Includes
Quantization
VREFL
VREFH
V
VREFL = VSSA
Power-Up Time
16
17
µs
Conversion Time
Period
Input Leakage (see Note 3)
Ports B and D
–1
1
µA
Conversion Time
16
17
ADC
Clock
Cycles
Conversion Range (see Note 1)
Monotonicity
Comments
Includes Sampling
Time
Inherent within Total Error
Zero Input Reading
00
01
Hex
VIN = VREFL
Full-Scale Reading
FE
FF
Hex
VIN = VREFH
Sample Time (see Note 2)
5
—
ADC
Clock
Cycles
Input Capacitance
—
8
pF
Not Tested
ADC Internal Clock
500 k
1.048 M
Hz
Tested Only at 1 MHz
Analog Input Voltage
VREFL
VREFH
V
1.VDD = 5.0 Vdc ± 0.5v, VSS = 0 Vdc, VDDA/VDDAREF = 5.0 Vdc ± 0.5v, VSSA = 0 Vdc, VREFH = 5.0 Vdc ± 0.5v
2.Source impedances greater than 10 kΩ adversely affect internal RC charging time during input sampling.
3.The external system error caused by input leakage current is approximately equal to the product of R
source and input current.
Technical Data
450
MC68HC08AZ60A — Rev 2.1
Electrical Specifications
Freescale Semiconductor
Electrical Specifications
25.8 5.0 Vdc ± 0.5 V Serial Peripheral Interface (SPI) Timing
Num
Symbol
Min
Max
Unit
Operating Frequency (see Note 3)
Master
Slave
fBUS(M)
fBUS(S)
fBUS/128
dc
fBUS/2
fBUS
MHz
1
Cycle Time
Master
Slave
tcyc(M)
tcyc(S)
2
1
128
—
tcyc
2
Enable Lead Time
tLead
15
—
ns
3
Enable Lag Time
tLag
15
—
ns
4
Clock (SCK) High Time
Master
Slave
tW(SCKH)M
tW(SCKH)S
100
50
—
—
ns
5
Clock (SCK) Low Time
Master
Slave
tW(SCKL)M
tW(SCKL)S
100
50
—
—
ns
6
Data Setup Time (Inputs)
Master
Slave
tSU(M)
tSU(S)
45
5
—
—
ns
7
Data Hold Time (Inputs)
Master
Slave
tH(M)
tH(S)
0
15
—
—
ns
tA(CP0)
tA(CP1)
0
0
40
20
ns
tDIS
—
25
ns
8
Characteristic
Access Time, Slave (see Note 4)
CPHA = 0
CPHA = 1
9
Slave Disable Time (Hold Time to High-Impedance State)
10
Enable Edge Lead Time to Data Valid (see Note 6)
Master
Slave
tEV(M)
tEV(S)
—
—
10
40
ns
11
Data Hold Time (Outputs, after Enable Edge)
Master
Slave
tHO(M)
tHO(S)
0
5
—
—
ns
12
Data Valid
Master (Before Capture Edge)
tV(M)
90
—
ns
13
Data Hold Time (Outputs)
Master (After Capture Edge)
tHO(M)
100
—
ns
NOTES:
1. All timing is shown with respect to 30% VDD and 70% VDD, unless otherwise noted; assumes 100 pF load on all SPI
pins.
2. Item numbers refer to dimensions in Figure 25-1 and Figure 25-2.
3. fBUS = the currently active bus frequency for the microcontroller.
4. Time to data active from high-impedance state.
5. With 100 pF on all SPI pins
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Electrical Specifications
451
Electrical Specifications
SS
(INPUT)
SS pin of master held high.
1
SCK (CPOL = 0)
(OUTPUT)
NOTE
SCK (CPOL = 1)
(OUTPUT)
NOTE
5
4
5
4
6
MISO
(INPUT)
MSB IN
BITS 6–1
10
11
MOSI
(OUTPUT)
MASTER MSB OUT
7
LSB IN
10
11
BITS 6–1
MASTER LSB OUT
13
12
NOTE: This first clock edge is generated internally, but is not seen at the SCK pin.
a) SPI Master Timing (CPHA = 0)
SS
(INPUT)
SS pin of master held high.
1
SCK (CPOL = 0)
(OUTPUT)
SCK (CPOL = 1)
(OUTPUT)
5
NOTE
4
5
NOTE
4
6
MISO
(INPUT)
MSB IN
10
MOSI
(OUTPUT)
BITS 6–1
11
MASTER MSB OUT
12
7
LSB IN
10
BITS 6–1
11
MASTER LSB OUT
13
NOTE: This last clock edge is generated internally, but is not seen at the SCK pin.
b) SPI Master Timing (CPHA = 1)
Figure 25-1. SPI Master Timing Diagram
Technical Data
452
MC68HC08AZ60A — Rev 2.1
Electrical Specifications
Freescale Semiconductor
Electrical Specifications
SS
(INPUT)
3
1
SCK (CPOL = 0)
(INPUT)
11
5
4
2
SCK (CPOL = 1)
(INPUT)
5
4
9
8
MISO
(INPUT)
SLAVE
MSB OUT
6
MOSI
(OUTPUT)
BITS 6–1
7
NOTE
11
11
10
MSB IN
SLAVE LSB OUT
BITS 6–1
LSB IN
NOTE: Not defined but normally MSB of character just received
a) SPI Slave Timing (CPHA = 0)
SS
(INPUT)
1
SCK (CPOL = 0)
(INPUT)
5
4
2
3
SCK (CPOL = 1)
(INPUT)
8
MISO
(OUTPUT)
MOSI
(INPUT)
5
4
10
NOTE
9
SLAVE
MSB OUT
6
7
BITS 6–1
11
10
MSB IN
SLAVE LSB OUT
BITS 6–1
LSB IN
NOTE: Not defined but normally LSB of character previously transmitted
b) SPI Slave Timing (CPHA = 1)
Figure 25-2. SPI Slave Timing Diagram
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Electrical Specifications
453
Electrical Specifications
25.9 CGM Operating Conditions
Characteristic
Symbol
Min
Typ
Max
Unit
VDDA
VDD-0.3
—
VDD+0.3
V
VSSA
VSS-0.3
—
VSS+0.3
V
Crystal Reference Frequency
fCGMRCLK
1
4.9152
16
MHz
Module Crystal Reference
Frequency
fCGMXCLK
—
4.9152
—
MHz
fNOM
—
4.9152
—
MHz
VCO Center-of-Range Frequency
fCGMVRS
4.9152
—
Note 1
MHz
VCO Operating Frequency
fCGMVCLK
4.9152
—
32.0
MHz
Comments
Operating Voltage
Range Nom. Multiplier
Same Frequency
as fCGMRCLK
1. fCGMVRS is a nominal value described and calculated as an example in the Clock Generator Module (CGM) section for
the desired VCO operating frequency, fCGMVCLK.
25.10 CGM Component Information
Description
Symbol
Min
Typ
Max
Unit
Crystal Load Capacitance
CL
—
—
—
—
Consult Crystal
Manufacturer’s Data
Crystal Fixed Capacitance
C1
—
2 x CL
—
—
Consult Crystal
Manufacturer’s Data
Crystal Tuning Capacitance
C2
—
2 x CL
—
—
Consult Crystal
Manufacturer’s Data
CFACT
—
0.0154
—
F/s V
—
CFACT x
(VDDA/
—
—
See External Filter Capacitor
Pin (CGMXFC) on page 151.
µF
CBYP must provide low AC
impedance from f =
fCGMXCLK/100 to 100 x
fCGMVCLK, so series resistance
must be considered.
Filter Capacitor Multiply Factor
Filter Capacitor
CF
fCGMXCLK)
Bypass Capacitor
CBYP
—
0.1 µF
—
Technical Data
454
Comments
MC68HC08AZ60A — Rev 2.1
Electrical Specifications
Freescale Semiconductor
Electrical Specifications
25.11 CGM Acquisition/Lock Time Information
Description
Symbol
Min
Typ
Max
Unit
Notes
Manual Mode Time to Stable
tACQ
—
(8 x VDDA) /
(fCGMXCLK x KACQ)
—
s
If CF Chosen
Correctly
Manual Stable to Lock Time
tAL
—
(4 x VDDA) /
(fCGMXCLK x KTRK)
—
s
If CF Chosen
Correctly
Manual Acquisition Time
tLOCK
—
tACQ+tAL
—
s
Tracking Mode Entry
Frequency Tolerance
DTRK
0
—
± 3.6
%
Acquisition Mode Entry
Frequency Tolerance
DUNT
± 6.3
—
± 7.2
%
LOCK Entry Freq. Tolerance
DLOCK
0
—
± 0.9
%
LOCK Exit Freq. Tolerance
DUNL
± 0.9
—
± 1.8
%
Reference Cycles per
Acquisition Mode
Measurement
nACQ
—
32
—
—
Reference Cycles per
Tracking Mode
Measurement
nTRK
—
128
—
—
Automatic Mode Time
to Stable
tACQ
nACQ/fCGM
(8 x VDDA) /
(fCGMXCLK x KACQ)
tAL
nTRK/fCGM
XCLK
(4 x VDDA) /
(fCGMXCLK x KTRK)
tLOCK
—
Automatic Stable to Lock
Time
Automatic Lock Time
PLL Jitter, Deviation of
Average Bus Frequency
over 2 ms (note 1)
s
If CF Chosen
Correctly
—
s
If CF Chosen
Correctly
1.26
25
ms
0
—
± (fCRYS)
x (.025%)
x (N/4)
%
XCLK
K value for automatic mode
time to stable
Kacq
—
0.7
—
—
K value
Ktrk
—
0.002
—
—
N = VCO
Freq. Mult.
NOTES:
1. Guaranteed but not tested.
2. VDD = 5.0 Vdc ± 0.5 V, VSS = 0 Vdc, TA = -40C to TA (MAX), unless otherwise noted.
3. Conditions for typical and maximum values are for Run mode with fCGMXCLK = 8MHz, fBUSDES = 8MHz, N = 4, L = 7,
discharged CF = 15 nF, VDD = 5Vdc.
4. Refer to Phase-Locked Loop (PLL) section for guidance on the use of the PLL.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Electrical Specifications
455
Electrical Specifications
25.12 RAM Memory Characteristics
Characteristic
Symbol
Min
Max
Unit
VRDR
0.7
—
V
Symbol
Min
Max
Unit
EEPROM Programming Time per Byte
tEEPGM
10
—
ms
EEPROM Erasing Time per Byte
tEEBYTE
10
—
ms
EEPROM Erasing Time per Block
tEEBLOCK
10
—
ms
EEPROM Erasing Time per Bulk
tEEBULK
10
—
ms
EEPROM Programming Voltage Discharge Period
tEEFPV
100
—
µs
Number of Programming Operations to the Same
EEPROM Byte Before Erase (1)
—
—
8
—
EEPROM Write/Erase Cycles
@ 10 ms Write Time
—
10,000
—
Cycles
EEPROM Data Retention
After 10,000 Write/Erase Cycles
—
10
—
Years
EEPROM Programming Maximum Time to
‘AUTO’ Bit Set
—
—
500
µs
EEPROM Erasing Maximum Time to ‘AUTO’ Bit
Set
—
—
8
ms
RAM Data Retention Voltage
25.13 EEPROM Memory Characteristics
Characteristic
NOTES:
1. Programming a byte more times than the specified maximum may affect the data integrity of that byte. The byte must
be erased before it can be programmed again.
Technical Data
456
MC68HC08AZ60A — Rev 2.1
Electrical Specifications
Freescale Semiconductor
Electrical Specifications
25.14 Mechanical Specifications
25.14.1 64-pin Quad Flat Pack (QFP)
L
33
-A-
-BB
Detail “A”
64
0.05 A – B
L
V
17
1
P
B
32
0.20 M C A – B S D S
49
0.20 M H A – B S D S
48
B
- A, B, D Detail “A”
F
N
J
16
-D-
Base
Metal
D
A
0.20 M C A – B S D S
Section B–B
0.05 A – B
0.20 M C A – B S D S
S
0.20 M H A – B S D S
U
T
Detail “C”
M
E
Q
C
-CSeating
Plane
R
Datum
-H- Plane
G
H
K
W
M
X
Dim.
Min.
Max.
Notes
Dim.
Min.
A
13.90
14.10
M
5°
10°
B
13.90
14.10
N
0.13
0.17
C
2.15
2.45
D
0.30
0.45
E
2.00
2.40
F
0.30
0.40
1. Datum Plane –H– is located at bottom of lead and is coincident with
the lead where the lead exits the plastic body at the bottom of the
parting line.
2. Datums A–B and –D to be determined at Datum Plane –H–.
3. Dimensions S and V to be determined at seating plane –C–.
4. Dimensions A and B do not include mould protrusion. Allowable
mould protrusion is 0.25mm per side. Dimensions A and B do
include mould mismatch and are determined at Datum Plane –H–.
5. Dimension D does not include dambar protrusion. Allowable
dambar protrusion shall be 0.08 total in excess of the D dimension
at maximum material condition. Dambar cannot be located on the
lower radius or the foot.
6. Dimensions and tolerancing per ANSI Y 14.5M, 1982.
7. All dimensions in mm.
G
0.80 BSC
H
—
0.25
J
0.13
0.23
K
0.65
0.95
L
12.00 REF
P
Max.
0.40 BSC
Q
0°
7°
R
0.13
0.30
S
16.95
17.45
T
0.13
—
U
0°
—
V
16.95
17.45
W
0.35
0.45
X
1.6 REF
Figure 25-3. 64-pin QFP (Case #840B)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Electrical Specifications
457
Electrical Specifications
Technical Data
458
MC68HC08AZ60A — Rev 2.1
Electrical Specifications
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 26. MC68HC08AZ60A Changes
26.1 Contents
26.2
Significant Changes from the MC68HC08AZ60 (Non-A Suffix
Device) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
26.2.1 Monitor ROM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
26.2.2 EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
26.2.3 Mask Option Registers . . . . . . . . . . . . . . . . . . . . . . . . . . 460
26.2.4 Low-Voltage Inhibit (LVI) . . . . . . . . . . . . . . . . . . . . . . . . . 461
26.2 Significant Changes from the MC68HC08AZ60 (Non-A Suffix Device)
26.2.1 Monitor ROM
The monitor ROM is now allocated 320 bytes within the memory map
though not all that space is necessarily used. Functionality of the monitor
ROM is unchanged.
26.2.2 EEPROM
26.2.2.1 EEPROM Architecture
The EEPROM-1 and EEPROM-2 are made from a new NVM
technology. However, the bit polarity remains the same i.e.
programmed=0, erased=1.
26.2.2.2 EEPROM Clock Source and Pre-scaler
The first major difference on the new EEPROM is that it requires a
constant time base source to ensure secure programming and erase
operations. This is done by firstly selecting which clock source is going
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MC68HC08AZ60A Changes
459
MC68HC08AZ60A Changes
to drive the EExDIV clock divider inputs using bit 7 of the new MORB
mask option register $FE09. Next the divide ratio from this source has to
be set by programming an 11-bit time base pre-scalar into bits spread
over two new registers, EExDIVH and EExDIVL (where x=1 or 2 for
EEPROM-1 and EEPROM-2 arrays).
The EExDIVH and EExDIVL registers are volatile. However, they are
loaded upon reset by the contents of duplicate non-volatile
EExDIVHNVR and EExDIVLNVR registers much in the same way as the
array control registers (EExACR) interacts with the non-volatile registers
(EExNVR) for configuration control on the existing revision. As a result
of the new EEDIV clock described above, bit 7 (EEBCLK) of the
EEPROM control registers (EExCR) is no longer used.
26.2.2.3 EEPROM AUTO Programming & Erasing
The second major change to the EEPROM is the inclusion in the
EEPROM control registers (EExCR) of an AUTO function using
previously unused bit 1 of that register.
The AUTO function enables the logic of the MCU to automatically use
the optimum programming or erasing time for the EEPROM. If using
AUTO the user does not need to wait for the normal minimum specified
programming or erasing time. After setting the EEPGM bit as normal the
user just has to poll that bit again, waiting for the MCU to clear it
indicating that programming or erasing is complete.
26.2.3 Mask Option Registers
26.2.3.1 Mask Option Register B
A new mask option register B (MORB) has been introduced for the Asuffix silicon. This contains two user-selectable bits and one fixed bit.
Bit 3 is a silicon hard set bit, which identifies this new A-suffix silicon.
Bit 4 is a bit that can enable EEPROM-1 and EEPROM-2 read protection
when in monitor mode.
Technical Data
460
MC68HC08AZ60A — Rev 2.1
MC68HC08AZ60A Changes
Freescale Semiconductor
MC68HC08AZ60A Changes
Bit 7 is an EEPROM time base divider clock select bit selecting the
reference clock source for the EEPROM time base divider module (refer
to EEPROM changes described above).
26.2.4 Low-Voltage Inhibit (LVI)
The Low-Voltage Inhibit (LVI) specifications for trip and recovery voltage
(VLVI) have been altered based upon module performance on silicon.
Please see for Electrical Specifications details.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MC68HC08AZ60A Changes
461
MC68HC08AZ60A Changes
Technical Data
462
MC68HC08AZ60A — Rev 2.1
MC68HC08AZ60A Changes
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Section 27. MC68HC08AZ48A Memory Map
27.1 Contents
27.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
27.2 Introduction
The MC68HC08AZ48A is basically identical to the MC68HC08AZ60A
part except that ROM, RAM and EEPROM sizes are smaller. The
memory map, shown in Figure 27-1, includes:
•
48,640 Bytes of ROM
•
1536 Bytes of RAM
•
768 Bytes of EEPROM with Protect Option
•
52 Bytes of User-Defined Vectors
•
256 Bytes of Monitor ROM
The following definitions apply to the memory map representation of
reserved and unimplemented locations.
•
Reserved — Accessing a reserved location can have
unpredictable effects on MCU operation.
•
Unused — These locations are reserved in the memory map for
future use, accessing an unused location can have unpredictable
effects on MCU operation.
•
Unimplemented — Accessing an unimplemented location can
cause an illegal address reset (within the constraints as outlined
in the System Integration Module (SIM)).
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MC68HC08AZ48A Memory Map
463
MC68HC08AZ48A Memory Map
MC68HC08AZ48A
$0000
↓
$004F
I/O REGISTERS (80 BYTES)
$0050
↓
$044F
RAM-1, 1024 BYTES
$0450
↓
$04FF
RESERVED (176 BYTES)
$0500
↓
$057F
CAN CONTROL AND MESSAGE
BUFFERS, 128 BYTES
$0580
↓
$05FF
RESERVED (128 BYTES)
$0600
↓
$06FF
EEPROM-2, 256BYTES
$0700
↓
$07FF
RESERVED (256 BYTES)
$0800
↓
$09FF
EEPROM-1, 512 BYTES
$0A00
↓
$0BFF
RAM-2 , 512 BYTES
$0C00
↓
$3FFF
RESERVED (13,312 BYTES)
$4000
↓
$7FFF
ROM-2, 16,384 BYTES
$8000
↓
$FDFF
ROM-1, 32,256BYTES
$FE00
SIM BREAK STATUS REGISTER (SBSR)
$FE01
SIM RESET STATUS REGISTER (SRSR)
Technical Data
464
MC68HC08AZ60A — Rev 2.1
MC68HC08AZ48A Memory Map
Freescale Semiconductor
MC68HC08AZ48A Memory Map
MC68HC08AZ48A
$FE02
RESERVED
$FE03
SIM BREAK FLAG CONTROL REGISTER (SBFCR)
$FE04
↓
$FE08
RESERVED (5 BYTES)
$FE09
MASK OPTION REGISTER B (MORB)
$FE0A
RESERVED
$FE0B
RESERVED
$FE0C
BREAK ADDRESS REGISTER HIGH (BRKH)
$FE0D
BREAK ADDRESS REGISTER LOW (BRKL)
$FE0E
BREAK STATUS AND CONTROL REGISTER (BSCR)
$FE0F
LVI STATUS REGISTER (LVISR)
$FE10
EEPROM-1EEDIVH NON-VOLATILE REGISTER (EE1DIVHNVR)
$FE11
EEPROM-1EEDIVL NON-VOLATILE REGISTER (EE1DIVLNVR)
$FE12
↓
$FE19
RESERVED (8 BYTES)
$FE1A
EEPROM-1 EE DIVIDER HIGH REGISTER (EE1DIVH)
$FE1B
EEPROM-1 EE DIVIDER LOW REGISTER (EE1DIVL)
$FE1C
EEPROM-1 EEPROM NON-VOLATILE REGISTER (EE1NVR)
$FE1D
EEPROM-1 EEPROM CONTROL REGISTER (EE1CR)
$FE1E
RESERVED
$FE1F
EEPROM-1 EEPROM ARRAY CONFIGURATION REGISTER (EE1ACR)
$FE20
↓
$FF1F
MONITOR ROM (256BYTES)
$FF20
↓
$FF6F
UNIMPLEMENTED (80 BYTES)
$FF70
EEPROM-2 EEDIVH NON-VOLATILE REGISTER (EE2DIVHNVR)
$FF71
EEPROM-2 EEDIVL NON-VOLATILE REGISTER (EE2DIVLNVR)
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
MC68HC08AZ48A Memory Map
465
MC68HC08AZ48A Memory Map
MC68HC08AZ48A
$FF72
↓
$FF79
RESERVED (8 BYTES)
$FF7A
EEPROM-2 EE DIVIDER HIGH REGISTER (EE2DIVH)
$FF7B
EEPROM-2 EE DIVIDER LOW REGISTER (EE2DIVL)
$FF7C
EEPROM-2 EEPROM NON-VOLATILE REGISTER (EE2NVR)
$FF7D
EEPROM-2 EEPROM CONTROL REGISTER (EE2CR)
$FF7E
RESERVED
$FF7F
EEPROM-2 EEPROM ARRAY CONFIGURATION REGISTER (EE2ACR)
$FF80
↓
$FFCB
RESERVED (76 BYTES)
$FFCC
↓
$FFFF
VECTORS (52BYTES)
Figure 27-1. Memory Map (Continued)
Technical Data
466
MC68HC08AZ60A — Rev 2.1
MC68HC08AZ48A Memory Map
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Revision History
27.3 Contents
27.4
Changes Between Revision 2.0 and Revision 1.0 . . . . . . . 467
27.5
Changes Between Revision 1.0 and Revision 0.0 . . . . . . . 467
27.4 Changes Between Revision 2.0 and Revision 1.0
The following table lists the changes between the current revision of the
MC68HC08AZ60A Technical Data Book, Rev 2.0, and the previous
revision, Rev 1.0.
Page
Number
Section affected
448
Electrical
Specifications
450
Description of change
Removed I/O ports hi-Z leakage current and second input current
entry from table. Also removed accompanying note.
Removed second input leakage entry and corresponding note from
table
27.5 Changes Between Revision 1.0 and Revision 0.0
The following table lists the changes between the current revision of the
MC68HC08AZ60A Technical Data Book, Rev 1.0, and the previous
revision, Advance Information Rev 0.0.
Section affected
Page
Number
Monitor ROM (MON)
179
Description of change
Zener diode value changed from TBD to 9.1V in Figure 12-1
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Revision History
467
Revision History
Section affected
Page
Number
446
448
Electrical
Specifications
455
455
455
Description of change
Reset and IRQ Input Voltage value changed to VDD + 4.0
High COP Disable Voltage and Monitor Mode Entry Voltage on IRQ
TBDs replaced by actual values
Automatic Lock Time typical value changed to 1.26
K value for automatic mode time to stable typical value changed to
0.7
K value typical value changed to 0.002
Technical Data
468
MC68HC08AZ60A — Rev 2.1
Revision History
Freescale Semiconductor
Technical Data — MC68HC08AZ60A
Glossary
A — See “accumulator (A).”
accumulator (A) — An 8-bit general-purpose register in the CPU08. The CPU08 uses the
accumulator to hold operands and results of arithmetic and logic operations.
acquisition mode — A mode of PLL operation during startup before the PLL locks on a
frequency. Also see "tracking mode."
address bus — The set of wires that the CPU or DMA uses to read and write memory locations.
addressing mode — The way that the CPU determines the operand address for an instruction.
The M68HC08 CPU has 16 addressing modes.
ALU — See “arithmetic logic unit (ALU).”
arithmetic logic unit (ALU) — The portion of the CPU that contains the logic circuitry to perform
arithmetic, logic, and manipulation operations on operands.
asynchronous — Refers to logic circuits and operations that are not synchronized by a common
reference signal.
baud rate — The total number of bits transmitted per unit of time.
BCD — See “binary-coded decimal (BCD).”
binary — Relating to the base 2 number system.
binary number system — The base 2 number system, having two digits, 0 and 1. Binary
arithmetic is convenient in digital circuit design because digital circuits have two
permissible voltage levels, low and high. The binary digits 0 and 1 can be interpreted to
correspond to the two digital voltage levels.
binary-coded decimal (BCD) — A notation that uses 4-bit binary numbers to represent the 10
decimal digits and that retains the same positional structure of a decimal number. For
example,
234 (decimal) = 0010 0011 0100 (BCD)
bit — A binary digit. A bit has a value of either logic 0 or logic 1.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Glossary
469
Glossary
branch instruction — An instruction that causes the CPU to continue processing at a memory
location other than the next sequential address.
break module — A module in the M68HC08 Family. The break module allows software to halt
program execution at a programmable point in order to enter a background routine.
breakpoint — A number written into the break address registers of the break module. When a
number appears on the internal address bus that is the same as the number in the break
address registers, the CPU executes the software interrupt instruction (SWI).
break interrupt — A software interrupt caused by the appearance on the internal address bus
of the same value that is written in the break address registers.
bus — A set of wires that transfers logic signals.
bus clock — The bus clock is derived from the CGMOUT output from the CGM. The bus clock
frequency, fop, is equal to the frequency of the oscillator output, CGMXCLK, divided by
four.
byte — A set of eight bits.
C — The carry/borrow bit in the condition code register. The CPU08 sets the carry/borrow bit
when an addition operation produces a carry out of bit 7 of the accumulator or when a
subtraction operation requires a borrow. Some logical operations and data manipulation
instructions also clear or set the carry/borrow bit (as in bit test and branch instructions and
shifts and rotates).
CCR — See “condition code register.”
central processor unit (CPU) — The primary functioning unit of any computer system. The
CPU controls the execution of instructions.
CGM — See “clock generator module (CGM).”
clear — To change a bit from logic 1 to logic 0; the opposite of set.
clock — A square wave signal used to synchronize events in a computer.
clock generator module (CGM) — A module in the M68HC08 Family. The CGM generates a
base clock signal from which the system clocks are derived. The CGM may include a
crystal oscillator circuit and or phase-locked loop (PLL) circuit.
comparator — A device that compares the magnitude of two inputs. A digital comparator defines
the equality or relative differences between two binary numbers.
computer operating properly module (COP) — A counter module in the M68HC08 Family that
resets the MCU if allowed to overflow.
Technical Data
470
MC68HC08AZ60A — Rev 2.1
Glossary
Freescale Semiconductor
Glossary
condition code register (CCR) — An 8-bit register in the CPU08 that contains the interrupt
mask bit and five bits that indicate the results of the instruction just executed.
control bit — One bit of a register manipulated by software to control the operation of the
module.
control unit — One of two major units of the CPU. The control unit contains logic functions that
synchronize the machine and direct various operations. The control unit decodes
instructions and generates the internal control signals that perform the requested
operations. The outputs of the control unit drive the execution unit, which contains the
arithmetic logic unit (ALU), CPU registers, and bus interface.
COP — See "computer operating properly module (COP)."
counter clock — The input clock to the TIM counter. This clock is the output of the TIM
prescaler.
CPU — See “central processor unit (CPU).”
CPU08 — The central processor unit of the M68HC08 Family.
CPU clock — The CPU clock is derived from the CGMOUT output from the CGM. The CPU
clock frequency is equal to the frequency of the oscillator output, CGMXCLK, divided by
four.
CPU cycles — A CPU cycle is one period of the internal bus clock, normally derived by dividing
a crystal oscillator source by two or more so the high and low times will be equal. The
length of time required to execute an instruction is measured in CPU clock cycles.
CPU registers — Memory locations that are wired directly into the CPU logic instead of being
part of the addressable memory map. The CPU always has direct access to the
information in these registers. The CPU registers in an M68HC08 are:
•
A (8-bit accumulator)
•
H:X (16-bit index register)
•
SP (16-bit stack pointer)
•
PC (16-bit program counter)
•
CCR (condition code register containing the V, H, I, N, Z, and C
bits)
CSIC — customer-specified integrated circuit
cycle time — The period of the operating frequency: tCYC = 1/fOP.
decimal number system — Base 10 numbering system that uses the digits zero through nine.
MC68HC08AZ60A — Rev 2.1
Freescale Semiconductor
Technical Data
Glossary
471
Glossary
direct memory access module (DMA) — A M68HC08 Family module that can perform data
transfers between any two CPU-addressable locations without CPU intervention. For
transmitting or receiving blocks of data to or from peripherals, DMA transfers are faster
and more code-efficient than CPU interrupts.
DMA — See "direct memory access module (DMA)."
DMA service request — A signal from a peripheral to the DMA module that enables the DMA
module to transfer data.
duty cycle — A ratio of the amount of time the signal is on versus the time it is off. Duty cycle is
usually represented by a percentage.
EEPROM — Electrically erasable, programmable, read-only memory. A nonvolatile type of
memory that can be electrically reprogrammed.
EPROM — Erasable, programmable, read-only memory. A nonvolatile type of memory that can
be erased by exposure to an ultraviolet light source and then reprogrammed.
exception — An event such as an interrupt or a reset that stops the sequential execution of the
instructions in the main program.
external interrupt module (IRQ) — A module in the M68HC08 Family with both dedicated
external interrupt pins and port pins that can be enabled as interrupt pins.
fetch — To copy data from a memory location into the accumulator.
firmware — Instructions and data programmed into nonvolatile memory.
free-running counter — A device that counts from zero to a predetermined number, then rolls
over to zero and begins counting again.
full-duplex transmission — Communication on a channel in which data can be sent and
received simultaneously.
H — The upper byte of the 16-bit index register (H:X) in the CPU08.
H — The half-carry bit in the condition code register of the CPU08. This bit indicates a carry from
the low-order four bits of the accumulator value to the high-order four bits. The half-carry
bit is required for binary-coded decimal arithmetic operations. The decimal adjust
accumulator (DAA) instruction uses the state of the H and C bits to determine the
appropriate correction factor.
hexadecimal — Base 16 numbering system that uses the digits 0 through 9 and the letters A
through F.
high byte — The most significant eight bits of a word.
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illegal address — An address not within the memory map
illegal opcode — A nonexistent opcode.
I — The interrupt mask bit in the condition code register of the CPU08. When I is set, all interrupts
are disabled.
index register (H:X) — A 16-bit register in the CPU08. The upper byte of H:X is called H. The
lower byte is called X. In the indexed addressing modes, the CPU uses the contents of
H:X to determine the effective address of the operand. H:X can also serve as a temporary
data storage location.
input/output (I/O) — Input/output interfaces between a computer system and the external world.
A CPU reads an input to sense the level of an external signal and writes to an output to
change the level on an external signal.
instructions — Operations that a CPU can perform. Instructions are expressed by programmers
as assembly language mnemonics. A CPU interprets an opcode and its associated
operand(s) and instruction.
interrupt — A temporary break in the sequential execution of a program to respond to signals
from peripheral devices by executing a subroutine.
interrupt request — A signal from a peripheral to the CPU intended to cause the CPU to
execute a subroutine.
I/O — See “input/output (I/0).”
IRQ — See "external interrupt module (IRQ)."
jitter — Short-term signal instability.
latch — A circuit that retains the voltage level (logic 1 or logic 0) written to it for as long as power
is applied to the circuit.
latency — The time lag between instruction completion and data movement.
least significant bit (LSB) — The rightmost digit of a binary number.
logic 1 — A voltage level approximately equal to the input power voltage (VDD).
logic 0 — A voltage level approximately equal to the ground voltage (VSS).
low byte — The least significant eight bits of a word.
low voltage inhibit module (LVI) — A module in the M68HC08 Family that monitors power
supply voltage.
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LVI — See "low voltage inhibit module (LVI)."
M68HC08 — A Freescale family of 8-bit MCUs.
mark/space — The logic 1/logic 0 convention used in formatting data in serial communication.
mask — 1. A logic circuit that forces a bit or group of bits to a desired state. 2. A photomask used
in integrated circuit fabrication to transfer an image onto silicon.
mask option — A optional microcontroller feature that the customer chooses to enable or
disable.
mask option register (MOR) — An EPROM location containing bits that enable or disable
certain MCU features.
MCU — Microcontroller unit. See “microcontroller.”
memory location — Each M68HC08 memory location holds one byte of data and has a unique
address. To store information in a memory location, the CPU places the address of the
location on the address bus, the data information on the data bus, and asserts the write
signal. To read information from a memory location, the CPU places the address of the
location on the address bus and asserts the read signal. In response to the read signal,
the selected memory location places its data onto the data bus.
memory map — A pictorial representation of all memory locations in a computer system.
microcontroller — Microcontroller unit (MCU). A complete computer system, including a CPU,
memory, a clock oscillator, and input/output (I/O) on a single integrated circuit.
modulo counter — A counter that can be programmed to count to any number from zero to its
maximum possible modulus.
monitor ROM — A section of ROM that can execute commands from a host computer for testing
purposes.
MOR — See "mask option register (MOR)."
most significant bit (MSB) — The leftmost digit of a binary number.
multiplexer — A device that can select one of a number of inputs and pass the logic level of that
input on to the output.
N — The negative bit in the condition code register of the CPU08. The CPU sets the negative bit
when an arithmetic operation, logical operation, or data manipulation produces a negative
result.
nibble — A set of four bits (half of a byte).
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object code — The output from an assembler or compiler that is itself executable machine code,
or is suitable for processing to produce executable machine code.
opcode — A binary code that instructs the CPU to perform an operation.
open-drain — An output that has no pullup transistor. An external pullup device can be
connected to the power supply to provide the logic 1 output voltage.
operand — Data on which an operation is performed. Usually a statement consists of an
operator and an operand. For example, the operator may be an add instruction, and the
operand may be the quantity to be added.
oscillator — A circuit that produces a constant frequency square wave that is used by the
computer as a timing and sequencing reference.
OTPROM — One-time programmable read-only memory. A nonvolatile type of memory that
cannot be reprogrammed.
overflow — A quantity that is too large to be contained in one byte or one word.
page zero — The first 256 bytes of memory (addresses $0000–$00FF).
parity — An error-checking scheme that counts the number of logic 1s in each byte transmitted.
In a system that uses odd parity, every byte is expected to have an odd number of logic
1s. In an even parity system, every byte should have an even number of logic 1s. In the
transmitter, a parity generator appends an extra bit to each byte to make the number of
logic 1s odd for odd parity or even for even parity. A parity checker in the receiver counts
the number of logic 1s in each byte. The parity checker generates an error signal if it finds
a byte with an incorrect number of logic 1s.
PC — See “program counter (PC).”
peripheral — A circuit not under direct CPU control.
phase-locked loop (PLL) — A oscillator circuit in which the frequency of the oscillator is
synchronized to a reference signal.
PLL — See "phase-locked loop (PLL)."
pointer — Pointer register. An index register is sometimes called a pointer register because its
contents are used in the calculation of the address of an operand, and therefore points to
the operand.
polarity — The two opposite logic levels, logic 1 and logic 0, which correspond to two different
voltage levels, VDD and VSS.
polling — Periodically reading a status bit to monitor the condition of a peripheral device.
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port — A set of wires for communicating with off-chip devices.
prescaler — A circuit that generates an output signal related to the input signal by a fractional
scale factor such as 1/2, 1/8, 1/10 etc.
program — A set of computer instructions that cause a computer to perform a desired operation
or operations.
program counter (PC) — A 16-bit register in the CPU08. The PC register holds the address of
the next instruction or operand that the CPU will use.
pull — An instruction that copies into the accumulator the contents of a stack RAM location. The
stack RAM address is in the stack pointer.
pullup — A transistor in the output of a logic gate that connects the output to the logic 1 voltage
of the power supply.
pulse-width — The amount of time a signal is on as opposed to being in its off state.
pulse-width modulation (PWM) — Controlled variation (modulation) of the pulse width of a
signal with a constant frequency.
push — An instruction that copies the contents of the accumulator to the stack RAM. The stack
RAM address is in the stack pointer.
PWM period — The time required for one complete cycle of a PWM waveform.
RAM — Random access memory. All RAM locations can be read or written by the CPU. The
contents of a RAM memory location remain valid until the CPU writes a different value or
until power is turned off.
RC circuit — A circuit consisting of capacitors and resistors having a defined time constant.
read — To copy the contents of a memory location to the accumulator.
register — A circuit that stores a group of bits.
reserved memory location — A memory location that is used only in special factory test modes.
Writing to a reserved location has no effect. Reading a reserved location returns an
unpredictable value.
reset — To force a device to a known condition.
ROM — Read-only memory. A type of memory that can be read but cannot be changed (written).
The contents of ROM must be specified before manufacturing the MCU.
SCI — See "serial communication interface module (SCI)."
serial — Pertaining to sequential transmission over a single line.
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serial communications interface module (SCI) — A module in the M68HC08 Family that
supports asynchronous communication.
serial peripheral interface module (SPI) — A module in the M68HC08 Family that supports
synchronous communication.
set — To change a bit from logic 0 to logic 1; opposite of clear.
shift register — A chain of circuits that can retain the logic levels (logic 1 or logic 0) written to
them and that can shift the logic levels to the right or left through adjacent circuits in the
chain.
signed — A binary number notation that accommodates both positive and negative numbers.
The most significant bit is used to indicate whether the number is positive or negative,
normally logic 0 for positive and logic 1 for negative. The other seven bits indicate the
magnitude of the number.
software — Instructions and data that control the operation of a microcontroller.
software interrupt (SWI) — An instruction that causes an interrupt and its associated vector
fetch.
SPI — See "serial peripheral interface module (SPI)."
stack — A portion of RAM reserved for storage of CPU register contents and subroutine return
addresses.
stack pointer (SP) — A 16-bit register in the CPU08 containing the address of the next available
storage location on the stack.
start bit — A bit that signals the beginning of an asynchronous serial transmission.
status bit — A register bit that indicates the condition of a device.
stop bit — A bit that signals the end of an asynchronous serial transmission.
subroutine — A sequence of instructions to be used more than once in the course of a program.
The last instruction in a subroutine is a return from subroutine (RTS) instruction. At each
place in the main program where the subroutine instructions are needed, a jump or branch
to subroutine (JSR or BSR) instruction is used to call the subroutine. The CPU leaves the
flow of the main program to execute the instructions in the subroutine. When the RTS
instruction is executed, the CPU returns to the main program where it left off.
synchronous — Refers to logic circuits and operations that are synchronized by a common
reference signal.
TIM — See "timer interface module (TIM)."
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timer interface module (TIM) — A module used to relate events in a system to a point in time.
timer — A module used to relate events in a system to a point in time.
toggle — To change the state of an output from a logic 0 to a logic 1 or from a logic 1 to a logic 0.
tracking mode — Mode of low-jitter PLL operation during which the PLL is locked on a
frequency. Also see "acquisition mode."
two’s complement — A means of performing binary subtraction using addition techniques. The
most significant bit of a two’s complement number indicates the sign of the number (1
indicates negative). The two’s complement negative of a number is obtained by inverting
each bit in the number and then adding 1 to the result.
unbuffered — Utilizes only one register for data; new data overwrites current data.
unimplemented memory location — A memory location that is not used. Writing to an
unimplemented location has no effect. Reading an unimplemented location returns an
unpredictable value. Executing an opcode at an unimplemented location causes an illegal
address reset.
V —The overflow bit in the condition code register of the CPU08. The CPU08 sets the V bit when
a two's complement overflow occurs. The signed branch instructions BGT, BGE, BLE,
and BLT use the overflow bit.
variable — A value that changes during the course of program execution.
VCO — See "voltage-controlled oscillator."
vector — A memory location that contains the address of the beginning of a subroutine written
to service an interrupt or reset.
voltage-controlled oscillator (VCO) — A circuit that produces an oscillating output signal of a
frequency that is controlled by a dc voltage applied to a control input.
waveform — A graphical representation in which the amplitude of a wave is plotted against time.
wired-OR — Connection of circuit outputs so that if any output is high, the connection point is
high.
word — A set of two bytes (16 bits).
write — The transfer of a byte of data from the CPU to a memory location.
X — The lower byte of the index register (H:X) in the CPU08.
Z — The zero bit in the condition code register of the CPU08. The CPU08 sets the zero bit when
an arithmetic operation, logical operation, or data manipulation produces a result of $00.
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Freescale Semiconductor
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Rev. 2.1
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August 5, 2005
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