Addendum to MC68HC908QB8, rev. 3
This addendum introduces a change to this data sheet.
Chapter 17 Development Support, Section 17.3.2 Security
A security feature discourages unauthorized reading of FLASH locations while in monitor mode. The host
can bypass the security feature at monitor mode entry by sending eight security bytes that match the
bytes at locations $FFF6–$FFFD. Locations $FFF6–$FFFD contain user-defined data.
NOTE
Do not leave locations $FFF6–$FFFD blank. For security reasons, program
locations $FFF6–$FFFD even if they are not used for vectors.
Changes to:
Chapter 17 Development Support, Section 17.3.2 Security
A security feature discourages unauthorized reading of FLASH locations while in monitor mode. The host
can bypass the security feature at monitor mode entry by sending eight security bytes that match the
bytes at locations $FFF6–$FFFD. Locations $FFF6–$FFFD contain user-defined data.
NOTE
Do not leave locations $FFF6–$FFFD blank. For security reasons, program
locations $FFF6–$FFFD even if they are not used for vectors. An improved
security function denies monitor mode entry if five or more of the eight
security bytes are $00 (zero bytes).
MC68HC908QB8 Data Sheet, Addendum 5/2012
Freescale Semiconductor
1
This page intentionally blank.
MC68HC908QB8 Data Sheet, Addendum 5/2012
2
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MC68HC908QB8
MC68HC908QB4
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Data Sheet
M68HC08
Microcontrollers
MC68HC908QB8
Rev. 3
04/2010
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MC68HC908QB8
MC68HC908QB4
MC68HC908QY8
Data Sheet
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MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
3
Revision History
The following revision history table summarizes changes contained in this document. For your
convenience, the page number designators have been linked to the appropriate location.
Revision History
Date
Revision
Level
September,
2005
1
April,
2007
April,
2010
2
3
Page
Number(s)
Description
Initial full release
N/A
Chapter 3 Analog-to-Digital Converter (ADC10) Module — Renamed ADCSC
register to ADSCR to be consistent with development tools.
37
Figure 4-1. Auto Wakeup Interrupt Request Generation Logic — Changed
BUSCLK4 to BUSCLK2 and removed reference to CGMXCLK
51
4.3 Functional Description — Reworked for clarity
52
4.6.4 Configuration Register 2 — Changed BUSCLK4 to BUSCLK2
55
4.6.5 Configuration Register 1 — Changed BUSCLK4 to BUSCLK2, added
bit description for SSREC, and removed SSREC from the note
56
Chapter 5 Configuration Register (CONFIG) — Changed CGMXCLK to
BUSCLKX4
57
Chapter 13 Enhanced Serial Communications Interface (ESCI) Module —
Changed SCIBDSRC to ESCIBDSRC, CGMXCLK to BUSCLKX4, and
BUS_CLK to BUS CLOCK
109
Table 13-5. ESCI LIN Control Bits — Corrected Functionality column
130
13.9.3 Bit Time Measurement — Corrected first sentence of listing number 1
136
Figure 17-18. Monitor Mode Entry Timing — Changed CGMXCLK to
BUSCLKX4
206
Clarify internal oscillator trim register information.
29, 36, 96,
101
MC68HC908QB8 Data Sheet, Rev. 3
4
Freescale Semiconductor
List of Chapters
Chapter 1
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Chapter 2
Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Chapter 3
Analog-to-Digital Converter (ADC10) Module . . . . . . . . . . . . . . . . . . . . . . . . . 37
Chapter 4
Auto Wakeup Module (AWU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Chapter 5
Configuration Register (CONFIG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Chapter 6
Computer Operating Properly (COP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Chapter 7
Central Processor Unit (CPU). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Chapter 8
External Interrupt (IRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Chapter 9
Keyboard Interrupt Module (KBI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
Chapter 10
Low-Voltage Inhibit (LVI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Chapter 11
Oscillator Module (OSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
Chapter 12
Input/Output Ports (PORTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Chapter 13
Enhanced Serial Communications Interface (ESCI) Module . . . . . . . . . . . . 109
Chapter 14
System Integration Module (SIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
5
List of Chapters
Chapter 15
Serial Peripheral Interface (SPI) Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Chapter 16
Timer Interface Module (TIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175
Chapter 17
Development Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Chapter 18
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .207
Chapter 19
Ordering Information and Mechanical Specifications . . . . . . . . . . . . . . . . . 227
MC68HC908QB8 Data Sheet, Rev. 3
6
Freescale Semiconductor
Table of Contents
Chapter 1
General Description
1.1
1.2
1.3
1.4
1.5
1.6
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MCU Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Function Priority. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
17
19
20
20
22
Chapter 2
Memory
2.1
2.2
2.3
2.4
2.5
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
2.6.6
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unimplemented Memory Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reserved Memory Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Direct Page Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Random-Access Memory (RAM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FLASH Memory (FLASH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FLASH Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FLASH Page Erase Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FLASH Mass Erase Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FLASH Program Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FLASH Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FLASH Block Protect Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
23
23
23
30
31
31
32
33
33
34
36
Chapter 3
Analog-to-Digital Converter (ADC10) Module
3.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.1
Clock Select and Divide Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2
Input Select and Pin Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3
Conversion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3.1
Initiating Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3.2
Completing Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3.3
Aborting Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.3.4
Total Conversion Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4
Sources of Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4.1
Sampling Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37
37
37
39
40
40
40
40
40
41
42
42
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
7
Table of Contents
3.3.4.2
Pin Leakage Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4.3
Noise-Induced Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4.4
Code Width and Quantization Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4.5
Linearity Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4.6
Code Jitter, Non-Monotonicity and Missing Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6
ADC10 During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7.1
ADC10 Analog Power Pin (VDDA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7.2
ADC10 Analog Ground Pin (VSSA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7.3
ADC10 Voltage Reference High Pin (VREFH). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7.4
ADC10 Voltage Reference Low Pin (VREFL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7.5
ADC10 Channel Pins (ADn). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8
Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8.1
ADC10 Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8.2
ADC10 Result High Register (ADRH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8.3
ADC10 Result Low Register (ADRL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8.4
ADC10 Clock Register (ADCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
42
42
43
43
43
44
44
44
44
44
45
45
45
45
45
46
46
46
48
48
49
Chapter 4
Auto Wakeup Module (AWU)
4.1
4.2
4.3
4.4
4.5
4.5.1
4.5.2
4.6
4.6.1
4.6.2
4.6.3
4.6.4
4.6.5
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Port A I/O Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Keyboard Status and Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Keyboard Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
51
51
52
52
53
53
53
53
53
54
54
55
55
Chapter 5
Configuration Register (CONFIG)
5.1
5.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Chapter 6
Computer Operating Properly (COP)
MC68HC908QB8 Data Sheet, Rev. 3
8
Freescale Semiconductor
6.1
6.2
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
6.3.7
6.4
6.5
6.6
6.6.1
6.6.2
6.7
6.8
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BUSCLKX4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
STOP Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COPCTL Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-On Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Internal Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COPD (COP Disable). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COPRS (COP Rate Select) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COP Module During Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
61
61
62
62
62
62
62
62
62
63
63
63
63
63
63
63
63
Chapter 7
Central Processor Unit (CPU)
7.1
7.2
7.3
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
7.4
7.5
7.5.1
7.5.2
7.6
7.7
7.8
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CPU Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Index Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Program Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Condition Code Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Arithmetic/Logic Unit (ALU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CPU During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Instruction Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Opcode Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
65
65
65
66
66
67
67
68
69
69
69
69
69
70
75
Chapter 8
External Interrupt (IRQ)
8.1
8.2
8.3
8.3.1
8.3.2
8.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
77
77
77
79
79
80
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
9
Table of Contents
8.5
8.5.1
8.5.2
8.6
8.7
8.7.1
8.8
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IRQ Module During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IRQ Input Pins (IRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
80
80
80
80
80
80
81
Chapter 9
Keyboard Interrupt Module (KBI)
9.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.2
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.1
Keyboard Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.1.1
MODEK = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.1.2
MODEK = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.2
Keyboard Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.4
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.6
KBI During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7
I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.7.1
KBI Input Pins (KBIx:KBI0). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8
Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.1
Keyboard Status and Control Register (KBSCR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.2
Keyboard Interrupt Enable Register (KBIER). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.8.3
Keyboard Interrupt Polarity Register (KBIPR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
83
83
83
83
84
85
86
86
86
86
86
86
87
87
87
87
88
88
Chapter 10
Low-Voltage Inhibit (LVI)
10.1
10.2
10.3
10.3.1
10.3.2
10.3.3
10.3.4
10.4
10.5
10.5.1
10.5.2
10.6
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Polled LVI Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forced Reset Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LVI Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LVI Trip Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LVI Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
89
89
89
90
90
90
90
91
91
91
91
91
MC68HC908QB8 Data Sheet, Rev. 3
10
Freescale Semiconductor
Chapter 11
Oscillator Module (OSC)
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
11.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
11.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
11.3.1
Internal Signal Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.1.1
Oscillator Enable Signal (SIMOSCEN). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.1.2
XTAL Oscillator Clock (XTALCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.1.3
RC Oscillator Clock (RCCLK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.1.4
Internal Oscillator Clock (INTCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.1.5
Bus Clock Times 4 (BUSCLKX4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.1.6
Bus Clock Times 2 (BUSCLKX2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.2
Internal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
11.3.2.1
Internal Oscillator Trimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
11.3.2.2
Internal to External Clock Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
11.3.2.3
External to Internal Clock Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
11.3.3
External Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
11.3.4
XTAL Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
11.3.5
RC Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
11.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
11.5 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
11.5.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
11.5.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
11.6 OSC During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
11.7 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
11.7.1
Oscillator Input Pin (OSC1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
11.7.2
Oscillator Output Pin (OSC2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
11.8 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
11.8.1
Oscillator Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
11.8.2
Oscillator Trim Register (OSCTRIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Chapter 12
Input/Output Ports (PORTS)
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2.1
Port A Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2.2
Data Direction Register A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2.3
Port A Input Pullup Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2.4
Port A Summary Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.3 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.3.1
Port B Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.3.2
Data Direction Register B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.3.3
Port B Input Pullup Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.3.4
Port B Summary Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
103
103
104
104
105
106
106
106
107
108
108
Chapter 13
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
11
Table of Contents
Enhanced Serial Communications Interface (ESCI) Module
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.1
Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.2
Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.2.1
Character Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.2.2
Character Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.2.3
Break Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.2.4
Idle Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.2.5
Inversion of Transmitted Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.3
Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.3.1
Character Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.3.2
Character Reception. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.3.3
Data Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.3.4
Framing Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.3.5
Baud Rate Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3.3.6
Receiver Wakeup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.4.1
Transmitter Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.4.2
Receiver Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.4.3
Error Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.5 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.5.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.5.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.6 ESCI During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.7 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.7.1
ESCI Transmit Data (TxD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.7.2
ESCI Receive Data (RxD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.1
ESCI Control Register 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.2
ESCI Control Register 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.3
ESCI Control Register 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.4
ESCI Status Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.5
ESCI Status Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.6
ESCI Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.7
ESCI Baud Rate Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.8.8
ESCI Prescaler Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.9 ESCI Arbiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.9.1
ESCI Arbiter Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.9.2
ESCI Arbiter Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.9.3
Bit Time Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.9.4
Arbitration Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
109
109
111
112
112
113
113
113
114
114
114
114
114
116
117
117
119
119
120
120
120
120
120
121
121
121
121
121
121
122
123
125
126
129
129
130
131
135
135
136
136
138
Chapter 14
System Integration Module (SIM)
MC68HC908QB8 Data Sheet, Rev. 3
12
Freescale Semiconductor
14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.2 RST and IRQ Pins Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.3 SIM Bus Clock Control and Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.3.1
Bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.3.2
Clock Start-Up from POR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.3.3
Clocks in Stop Mode and Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4 Reset and System Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4.1
External Pin Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4.2
Active Resets from Internal Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4.2.1
Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4.2.2
Computer Operating Properly (COP) Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4.2.3
Illegal Opcode Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4.2.4
Illegal Address Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4.2.5
Low-Voltage Inhibit (LVI) Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.5 SIM Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.5.1
SIM Counter During Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.5.2
SIM Counter During Stop Mode Recovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.5.3
SIM Counter and Reset States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6 Exception Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.1
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.1.1
Hardware Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.1.2
SWI Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.2
Interrupt Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.2.1
Interrupt Status Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.2.2
Interrupt Status Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.2.3
Interrupt Status Register 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.3
Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.4
Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.6.5
Status Flag Protection in Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.7 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.7.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.7.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.8 SIM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.8.1
SIM Reset Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.8.2
Break Flag Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
139
139
140
141
141
141
141
141
142
143
143
143
144
144
144
144
144
144
145
145
145
148
148
149
149
149
150
150
150
150
150
151
152
152
153
Chapter 15
Serial Peripheral Interface (SPI) Module
15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.1
Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.2
Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.3
Transmission Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.3.1
Clock Phase and Polarity Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.3.2
Transmission Format When CPHA = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
155
155
157
158
158
159
159
159
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
13
Table of Contents
15.3.3.3
Transmission Format When CPHA = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.3.4
Transmission Initiation Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.4
Queuing Transmission Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.5
Resetting the SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.6
Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.6.1
Overflow Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.3.6.2
Mode Fault Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.5 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.5.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.5.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.6 SPI During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.7 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.7.1
MISO (Master In/Slave Out). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.7.2
MOSI (Master Out/Slave In). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.7.3
SPSCK (Serial Clock) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.7.4
SS (Slave Select) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.8 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.8.1
SPI Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.8.2
SPI Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.8.3
SPI Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
160
161
163
164
164
164
166
167
168
168
168
168
169
169
169
169
169
170
171
172
174
Chapter 16
Timer Interface Module (TIM)
16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.1
TIM Counter Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.2
Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.3
Output Compare. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.3.1
Unbuffered Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.3.2
Buffered Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.4
Pulse Width Modulation (PWM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.4.1
Unbuffered PWM Signal Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.4.2
Buffered PWM Signal Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.3.4.3
PWM Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.5 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.5.1
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.5.2
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.6 TIM During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.7 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.7.1
TIM Channel I/O Pins (TCH3:TCH0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.7.2
TIM Clock Pin (TCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.8 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.8.1
TIM Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
175
175
175
175
176
177
178
178
179
179
180
181
182
182
182
182
182
183
183
183
183
183
MC68HC908QB8 Data Sheet, Rev. 3
14
Freescale Semiconductor
16.8.2
16.8.3
16.8.4
16.8.5
TIM Counter Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TIM Counter Modulo Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TIM Channel Status and Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TIM Channel Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
185
185
186
188
Chapter 17
Development Support
17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2 Break Module (BRK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.1
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.1.1
Flag Protection During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.1.2
TIM During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.1.3
COP During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.2
Break Module Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.2.1
Break Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.2.2
Break Address Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.2.3
Break Auxiliary Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.2.4
Break Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.2.5
Break Flag Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.2.3
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3 Monitor Module (MON) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1.1
Normal Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1.2
Forced Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1.3
Monitor Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1.4
Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1.5
Break Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1.6
Baud Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.1.7
Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17.3.2
Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
191
191
191
193
193
193
194
194
194
195
195
195
196
196
196
200
201
201
202
202
202
202
206
Chapter 18
Electrical Specifications
18.1
18.2
18.3
18.4
18.5
18.6
18.7
18.8
18.9
18.10
18.11
18.12
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-V DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical 5-V Output Drive Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-V Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-V DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical 3-V Output Drive Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-V Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oscillator Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
207
207
208
208
209
210
211
212
213
214
215
217
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
15
Table of Contents
18.13
18.14
18.15
18.16
18.17
ADC10 Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.0-Volt SPI Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.0-Volt SPI Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timer Interface Module Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Memory Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
219
221
222
225
226
Chapter 19
Ordering Information and Mechanical Specifications
19.1
19.2
19.3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
MC Order Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
MC68HC908QB8 Data Sheet, Rev. 3
16
Freescale Semiconductor
Chapter 1
General Description
1.1 Introduction
The MC68HC908QB8 is a member of the low-cost, high-performance M68HC08 Family of 8-bit
microcontroller units (MCUs). 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.
0.4
Table 1-1. Summary of Device Variations
Device
FLASH/RAM
Memory Size
ADC
16-Bit Timer
Channels
ESCI
SPI
Pin
Count
MC68HC908QB8
8K/256 bytes
10 channel, 10 bit
4
Yes
Yes
16 pins
MC68HC908QB4
4K/128 bytes
10 channel, 10 bit
4
Yes
Yes
16 pins
MC68HC908QY8
8K/256 bytes
4 channel, 10 bit
2
No
No
16 pins
1.2 Features
Features include:
• High-performance M68HC08 CPU core
• Fully upward-compatible object code with M68HC05 Family
• 5-V and 3-V operating voltages (VDD)
• 8-MHz internal bus operation at 5 V, 4-MHz at 3 V
• Trimmable internal oscillator
– Software selectable 1 MHz, 2 MHz, or 3.2 MHz internal bus operation
– 8-bit trim capability
– ± 25% untrimmed
– Trimmable to approximately 0.4%(1)
• Software selectable crystal oscillator range, 32–100 kHz, 1–8 MHz, and 8–32 MHz
• Software configurable input clock from either internal or external source
• Auto wakeup from STOP capability using dedicated internal 32-kHz RC or bus clock source
• On-chip in-application programmable FLASH memory
– Internal program/erase voltage generation
– Monitor ROM containing user callable program/erase routines
– FLASH security(2)
1. See 18.11 Oscillator Characteristics for internal oscillator specifications
2. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or copying the FLASH difficult for
unauthorized users.
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
17
General Description
•
•
•
•
•
•
•
•
•
•
•
•
•
•
On-chip random-access memory (RAM)
Enhanced serial communications interface (ESCI) module
Serial peripheral interface (SPI) module
4-channel, 16-bit timer interface (TIM) module
10-channel, 10-bit analog-to-digital converter (ADC) with internal bandgap reference channel
(ADC10)
Up to 13 bidirectional input/output (I/O) lines and one input only:
– Six shared with KBI
– Ten shared with ADC
– Four shared with TIM
– Two shared with ESCI
– Four shared with SPI
– One input only shared with IRQ
– High current sink/source capability on all port pins
– Selectable pullups on all ports, selectable on an individual bit basis
– Three-state ability on all port pins
6-bit keyboard interrupt with wakeup feature (KBI)
– Programmable for rising/falling or high/low level detect
Low-voltage inhibit (LVI) module features:
– Software selectable trip point
System protection features:
– Computer operating properly (COP) watchdog
– Low-voltage detection with reset
– Illegal opcode detection with reset
– Illegal address detection with reset
External asynchronous interrupt pin with internal pullup (IRQ) shared with general-purpose input
pin
Master asynchronous reset pin with internal pullup (RST) shared with general-purpose input/output
(I/O) pin
Memory mapped I/O registers
Power saving stop and wait modes
MC68HC908QB8, MC68HC908QB4 and MC68HC908QY8 are available in these packages:
– 16-pin plastic dual in-line package (PDIP)
– 16-pin small outline integrated circuit (SOIC) package
– 16-pin thin shrink small outline packages (TSSOP)
Features of the CPU08 include the following:
• Enhanced HC05 programming model
• Extensive loop control functions
• 16 addressing modes (eight 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
• Efficient C language support
MC68HC908QB8 Data Sheet, Rev. 3
18
Freescale Semiconductor
MCU Block Diagram
1.3 MCU Block Diagram
Figure 1-1 shows the structure of the MC68HC908QB8.
PTA0/TCH0/AD0/KBI0
CLOCK
GENERATOR
PTA3/RST/KBI3
PTA
PTA2/IRQ/KBI2/TCLK
DDRA
PTA1/TCH1/AD1/KBI1
KEYBOARD INTERRUPT
MODULE
PTA4/OSC2/AD2/KBI4
PTA5/OSC1/AD3/KBI5
SINGLE INTERRUPT
MODULE
AUTO WAKEUP
MODULE
DDRB
PTB0/SPSCK/AD4
PTB1/MOSI/AD5
PTB2/MISO/AD6
PTB3/SS/AD7
PTB4/RxD/AD8
PTB5/TxD/AD9
PTB6/TCH2
PTB7/TCH3
PTB
M68HC08 CPU
LOW-VOLTAGE
INHIBIT
4-CHANNEL 16-BIT
TIMER MODULE
MC68HC908QB8
MC68HC908QB8
256 BYTES
8192 BYTES
USER RAM
USER FLASH
10-CHANNEL
10-BIT ADC
ENHANCED SERIAL
COMMUNICATIONS
INTERFACE MODULE
VDD
POWER SUPPLY
COP
MODULE
VSS
SERIAL PERIPHERAL
INTERFACE
DEVELOPMENT SUPPORT
MONITOR ROM
BREAK MODULE
RST, IRQ: Pins have internal pull up device
All port pins have programmable pull up device
PTA[0:5]: Higher current sink and source capability
Figure 1-1. Block Diagram
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
19
General Description
1.4 Pin Assignments
The MC68HC908QB8, MC68HC908QB4, and MC68HC908QY8 are available in 16-pin packages.
Figure 1-2 shows the pin assignment for these packages.
VDD
1
16
VSS
PTB7
2
15
PTB0
PTB6
3
14
PTB1
PTA5/OSC1/AD3/KBI5
4
13
PTA0/TCH0/AD0/KBI0
PTA4/OSC2/AD2/KBI4
5
12
PTA1/TCH1/AD1/KBI1
PTB5
6
11
PTB2
PTB4
7
10
PTB3
PTA3/RST/KBI3
8
9
PTA2/IRQ/KBI2/TCLK
PTA0/TCH0/AD0/KBI0
PTB1
PTB0
VSS
VDD
PTB7
PTB6
PTA5/OSC1/AD3/KBI5
1
2
3
4
5
6
7
8
PTA1/TCH1/AD1/KBI1
PTB2
PTB3
PTA2/IRQ/KBI2/TCLK
PTA3/RST/KBI3
PTB4
PTB5
PTA4/OSC2/AD2/KBI4
16
15
14
13
12
11
10
9
16-PIN ASSIGNMENT
MC68HC908QY8 TSSOP
16-PIN ASSIGNMENT
MC68HC908QY8 PDIP/SOIC
VDD
1
16
VSS
PTB7/TCH3
2
15
PTB0/SCK/AD4
PTB6/TCH2
3
14
PTB1/MOSI/AD5
PTA5/OSC1/AD3/KBI5
4
13
PTA0/TCH0/AD0/KBI0
PTA4/OSC2/AD2/KBI4
5
12
PTA1/TCH1/AD1/KBI1
PTB5/Tx/AD9
6
11
PTB2/MISO/AD6
PTB4/Rx/AD8
7
10
PTB3/SS/AD7
PTA3/RST/KBI3
8
9
PTA2/IRQ/KBI2/TCLK
PTA0/TCH0/AD0/KBI0
PTB1/MOSI/AD5
PTB0/SCK/AD4
VSS
VDD
PTB7/TCH3
PTB6/TCH2
PTA5/OSC1/AD3/KBI5
16-PIN ASSIGNMENT
MC68HC908QB8/MC68HC908QB4 PDIP/SOIC
PTA1/TCH1/AD1/KBI1
16
PTB2/MISO/AD6
15
PTB3/SS/AD7
14
PTA2/IRQ/KBI2/TCLK
13
PTA3/RST/KBI3
12
PTB4//Rx/AD8
11
PTB5/Tx/AD9
10
PTA4/OSC2/AD2/KBI4
9
16-PIN ASSIGNMENT
MC68HC908QB8/MC68HC908QB4 TSSOP
1
2
3
4
5
6
7
8
Figure 1-2. MCU Pin Assignments
1.5 Pin Functions
Table 1-2 provides a description of the pin functions.
MC68HC908QB8 Data Sheet, Rev. 3
20
Freescale Semiconductor
Pin Functions
Table 1-2. Pin Functions
Pin
Name
Description
Input/Output
VDD
Power supply
Power
VSS
Power supply ground
Power
PTA0
PTA1
PTA2
PTA0 — General purpose I/O port
Input/Output
TCH0 — Timer Channel 0 I/O
Input/Output
AD0 — A/D channel 0 input
Input
KBI0 — Keyboard interrupt input 0
Input
PTA1 — General purpose I/O port
Input/Output
TCH1 — Timer Channel 1 I/O
Input/Output
AD1 — A/D channel 1 input
Input
KBI1 — Keyboard interrupt input 1
Input
PTA2 — General purpose input-only port
Input
IRQ — External interrupt with programmable pullup and Schmitt trigger input
Input
KBI2 — Keyboard interrupt input 2
Input
TCLK — Timer clock input
Input
PTA3 — General purpose I/O port
PTA3
PTA4
PTA5
PTB0
RST — Reset input, active low with internal pullup and Schmitt trigger
Input
PTA4 — General purpose I/O port
Input/Output
OSC2 —XTAL oscillator output (XTAL option only)
RC or internal oscillator output (OSC2EN = 1 in PTAPUE register)
Input
KBI4 — Keyboard interrupt input 4
Input
PTA5 — General purpose I/O port
Input/Output
OSC1 — XTAL, RC, or external oscillator input
Input
AD3 — A/D channel 3 input
Input
KBI5 — Keyboard interrupt input 5
Input
PTB0 — General-purpose I/O port
Input/Output
SPSCK — SPI serial clock
Input/Output
Input
PTB1 — General-purpose I/O port
Input/Output
MOSI — SPI Master out Slave in
Input/Output
Input
PTB2 — General-purpose I/O port
Input/Output
MISO — SPI Master in Slave out
Input/Output
AD6 — A/D channel 6 input
Input
PTB3 — General-purpose I/O port
PTB3
Output
Output
AD2 — A/D channel 2 input
AD5 — A/D channel 5 input
PTB2
Input
KBI3 — Keyboard interrupt input 3
AD4 — A/D channel 4 input
PTB1
Input/Output
Input/Output
SS — SPI slave select
Input
AD7 — A/D channel 7 input
Input
— Continued on next page
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
21
General Description
Table 1-2. Pin Functions (Continued)
Pin
Name
PTB4
Description
Input/Output
PTB4 — General-purpose I/O port
Input/Output
RxD — ESCI receive data I/O
Input/Output
AD8 — A/D channel 8 input
Input
PTB5 — General-purpose I/O port
PTB5
Input/Output
TxD — ESCI transmit data I/O
Output
AD9 — A/D channel 9 input
PTB6
PTB7
Input
PTB6 — General-purpose I/O port
Input/Output
TCH2 — Timer channel 2 I/O
Input/Output
PTB7 — General-purpose I/O port
Input/Output
TCH3 — Timer channel 3 I/O
Input/Output
1.6 Pin Function Priority
Table 1-3 is meant to resolve the priority if multiple functions are enabled on a single pin.
NOTE
Upon reset all pins come up as input ports regardless of the priority table.
Table 1-3. Function Priority in Shared Pins
Pin Name
Highest-to-Lowest Priority Sequence
PTA0(1)
AD0 → TCH0 → KBI0 → PTA0
PTA1(1)
AD1 → TCH1 → KBI1 → PTA1
PTA2
IRQ → TCLK → KBI2 → PTA2
PTA3
RST → KBI3 → PTA3
PTA4(1)
OSC2 → AD2 → KBI4 → PTA4
PTA5(1)
OSC1 → AD3 → KBI5 → PTA5
PTB0(1)
AD4 → SPSCK → PTB0
(1)
PTB1
AD5 → MOSI → PTB1
PTB2(1)
AD6 → MISO → PTB2
PTB3(1)
AD7 → SS → PTB3
(1)
PTB4
AD8 → RxD → PTB4
PTB5(1)
AD9 → TxD → PTB5
PTB6
TCH2 → PTB6
PTB7
TCH3 → PTB7
1. When a pin is to be used as an ADC pin, the I/O port function should be left as
an input and all other shared modules should be disabled. The ADC does not
override additional modules using the pin.
MC68HC908QB8 Data Sheet, Rev. 3
22
Freescale Semiconductor
Chapter 2
Memory
2.1 Introduction
The central processor unit (CPU08) can address 64 Kbytes of memory space. The memory map, shown
in Figure 2-1.
2.2 Unimplemented Memory Locations
Executing code from an unimplemented location will cause an illegal address reset. In Figure 2-1,
unimplemented locations are shaded.
2.3 Reserved Memory Locations
Accessing a reserved location can have unpredictable effects on MCU operation. In Figure 2-1, register
locations are marked with the word Reserved or with the letter R.
2.4 Direct Page Registers
Figure 2-2 shows the memory mapped registers of the MC68HC908QB8. Registers with addresses
between $0000 and $00FF are considered direct page registers and all instructions including those with
direct page addressing modes can access them. Registers between $0100 and $FFFF require non-direct
page addressing modes. See Chapter 7 Central Processor Unit (CPU) for more information on
addressing modes.
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
23
Memory
$0000
↓
$003F
IDIRECT PAGE REGISTERS
64 BYTES
$0040
↓
$013F
RAM
256 BYTES
RESERVED
64 BYTES
$0040
↓
$007F
$0140
↓
$27FF
UNIMPLEMENTED
9920 BYTES
RAM
128 BYTES
$0080
↓
$00FF
$2800
↓
$2A1F
AUXILIARY ROM
544 BYTES
RESERVED
64 BYTES
$0100
↓
$013F
$2A20
↓
$2F7D
UNIMPLEMENTED
1374 BYTES
$2F7E
↓
$2FFF
AUXILIARY ROM
130 BYTES
$3000
↓
$DDFF
UNIMPLEMENTED
44,544 BYTES
$DE00
↓
$FDFF
FLASH MEMORY
8192 BYTES
RESERVED
4096 BYTES
$DE00
↓
$EDFF
$FE00
↓
$FE1F
MISCELLANEOUS REGISTERS
32 BYTES
FLASH MEMORY
4096 BYTES
$EE00
↓
$FDFF
$FE20
↓
$FF7D
MONITOR ROM
350 BYTES
$FF7E
↓
$FFAF
UNIMPLEMENTED
50BYTES
$FFB0
↓
$FFBD
FLASH
14 BYTES
$FFBE
↓
$FFC1
MISCELLANEOUS REGISTERS
4 BYTES
$FFC2
↓
$FFCF
FLASH
14 BYTES
$FFD0
↓
$FFFF
USER VECTORS
48 BYTES
MC68HC908QB8 and MC68HC908QY8
Memory Map
MC68HC908QB4
Memory Map
Figure 2-1. Memory Map
MC68HC908QB8 Data Sheet, Rev. 3
24
Freescale Semiconductor
Direct Page Registers
Addr.
$0000
$0001
$0002
↓
$0003
$0004
$0005
$0006
↓
$000A
$000B
$000C
$000D
$000E
$000F
$0010
$0011
$0012
$0013
Register Name
Port A Data Register Read:
(PTA) Write:
See page 104. Reset:
Port B Data Register Read:
(PTB) Write:
See page 106. Reset:
Bit 7
R
6
AWUL
5
4
3
PTA5
PTA4
PTA3
2
PTA2
1
Bit 0
PTA1
PTA0
PTB1
PTB0
DDRA1
DDRA0
Unaffected by reset
PTB7
PTB6
PTB5
PTB4
PTB3
PTB2
Unaffected by reset
Reserved
Data Direction Register A Read:
(DDRA) Write:
See page 104. Reset:
Data Direction Register B Read:
(DDRB) Write:
See page 107. Reset:
0
R
R
DDRA5
DDRA4
DDRA3
0
0
0
0
0
0
0
0
DDRB7
DDRB6
DDRB5
DDRB4
DDRB3
DDRB2
DDRB1
DDRB0
0
0
0
0
0
0
0
0
PTAPUE5
PTAPUE4
PTAPUE3
PTAPUE2
PTAPUE1
PTAPUE0
0
0
0
0
0
0
0
PTBPUE6
PTBPUE5
PTBPUE4
PTBPUE3
PTBPUE2
PTBPUE1
PTBPUE0
0
0
0
0
0
0
0
R
SPMSTR
CPOL
CPHA
SPWOM
SPE
SPTIE
0
1
OVRF
0
MODF
1
SPTE
0
0
0
MODFEN
SPR1
SPR0
0
R2
T2
0
R1
T1
0
R0
T0
Reserved
Port A Input Pullup Enable Read:
OSC2EN
Register (PTAPUE) Write:
See page 105. Reset:
0
Read:
Port B Input Pullup Enable
PTBPUE7
Register (PTBPUE) Write:
See page 108. Reset:
0
Read:
SPI Control Register
SPRIE
(SPCR) Write:
See page 171. Reset:
0
Read:
SPRF
SPI Status and Control
Register (SPSCR) Write:
See page 172. Reset:
0
Read:
R7
SPI Data Register
(SPDR) Write:
T7
See page 174. Reset:
ESCI Control Register 1 Read:
LOOPS
(SCC1) Write:
See page 122. Reset:
0
Read:
ESCI Control Register 2
SCTIE
(SCC2) Write:
See page 124. Reset:
0
Read:
R8
ESCI Control Register 3
(SCC3) Write:
See page 125. Reset:
U
Read:
SCTE
ESCI Status Register 1
(SCS1) Write:
See page 126. Reset:
1
0
ERRIE
0
R6
T6
0
R5
T5
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
0
TC
0
SCRF
0
IDLE
0
OR
0
NF
0
FE
0
PE
0
R
0
= Reserved
1
0
= Unimplemented
0
1
R4
R3
T4
T3
Unaffected by reset
0
0
U = Unaffected
0
Figure 2-2. Control, Status, and Data Registers (Sheet 1 of 5)
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
25
Memory
Addr.
$0014
$0015
$0016
$0017
$0018
$0019
$001A
$001B
$001C
$001D
$001E
$001F
$0020
$0021
Register Name
ESCI Status Register 2 Read:
(SCS2) Write:
See page 129. Reset:
ESCI Data Register Read:
(SCDR) Write:
See page 129. Reset:
ESCI Baud Rate Register Read:
(SCBR) Write:
See page 130. Reset:
ESCI Prescaler Register Read:
(SCPSC) Write:
See page 131. Reset:
ESCI Arbiter Control Read:
Register (SCIACTL) Write:
See page 135. Reset:
ESCI Arbiter Data Register Read:
(SCIADAT) Write:
See page 136. Reset:
Keyboard Status and Read:
Control Register (KBSCR) Write:
See page 87. Reset:
Keyboard Interrupt Read:
Enable Register (KBIER) Write:
See page 88. Reset:
Keyboard Interrupt Polarity Read:
Register (KBIPR) Write:
See page 88. Reset:
IRQ Status and Control Read:
Register (INTSCR) Write:
See page 81. Reset:
Configuration Register 2 Read:
(CONFIG2)(1) Write:
See page 57. Reset:
Configuration Register 1 Read:
(CONFIG1)(1) Write:
See page 58. Reset:
TIM Status and Control Read:
Register (TSC) Write:
See page 183. Reset:
TIM Counter Register High Read:
(TCNTH) Write:
See page 185. Reset:
Bit 7
0
6
0
5
0
0
R7
T7
0
R6
T6
0
R5
T5
LINT
LINR
SCP1
SCP0
0
0
0
PDS2
PDS1
0
0
ALOST
AM1
4
0
3
0
2
0
1
BKF
Bit 0
RPF
0
R2
T2
0
R1
T1
0
R0
T0
R
SCR2
SCR1
SCR0
0
0
0
0
0
PDS0
PSSB4
PSSB3
PSSB2
PSSB1
PSSB0
0
0
AM0
ACLK
0
AFIN
0
ARUN
0
AROVFL
0
ARD8
0
0
R4
R3
T4
T3
Unaffected by reset
0
ARD7
0
ARD6
0
ARD5
0
ARD4
0
ARD3
0
ARD2
0
ARD1
0
ARD0
0
0
0
0
0
0
0
0
0
KEYF
0
0
IMASKK
MODEK
0
0
0
0
0
0
0
0
ACKK
0
0
0
AWUIE
KBIE5
KBIE4
KBIE3
KBIE2
KBIE1
KBIE0
0
0
0
0
0
0
0
0
0
0
KBIP5
KBIP4
KBIP3
KBIP2
KBIP1
KBIP0
0
0
0
0
0
0
0
0
0
IRQF
0
0
IMASK
MODE
0
0
0
0
0
0
0
ACK
0
IRQPUD
IRQEN
R
R
R
0
0
0
0
1. One-time writable register after each reset.
2. RSTEN reset to 0 by a power-on reset (POR) only.
COPRS
LVISTOP
LVIRSTD
0
LVIPWRD
0
0
0
0
1. One-time writable register after each reset.
2. LVITRIP reset to 0 by a power-on reset (POR) only.
TOF
0
0
Bit 15
0
TOIE
TSTOP
0
Bit 14
1
Bit 13
0
0
= Unimplemented
0
OSCENINESCIBDSRC
STOP
0
0
0
RSTEN
0(2)
LVITRIP
SSREC
STOP
COPD
0(2)
0
0
0
PS2
PS1
PS0
0
Bit 10
0
Bit 9
0
Bit 8
0
TRST
0
Bit 12
0
0
Bit 11
0
R
0
= Reserved
0
0
U = Unaffected
0
Figure 2-2. Control, Status, and Data Registers (Sheet 2 of 5)
MC68HC908QB8 Data Sheet, Rev. 3
26
Freescale Semiconductor
Direct Page Registers
Addr.
$0022
$0023
$0024
$0025
$0026
$0027
$0028
$0029
$002A
$002B
↓
$002F
$0030
$0031
$0032
$0033
$0034
$0035
Register Name
TIM Counter Register Low Read:
(TCNTL) Write:
See page 185. Reset:
TIM Counter Modulo Read:
Register High (TMODH) Write:
See page 185. Reset:
TIM Counter Modulo Read:
Register Low (TMODL) Write:
See page 185. Reset:
TIM Channel 0 Status and Read:
Control Register (TSC0) Write:
See page 186. Reset:
TIM Channel 0 Read:
Register High (TCH0H) Write:
See page 189. Reset:
TIM Channel 0 Read:
Register Low (TCH0L) Write:
See page 189. Reset:
TIM Channel 1 Status and Read:
Control Register (TSC1) Write:
See page 186. Reset:
TIM Channel 1 Read:
Register High (TCH1H) Write:
See page 189. Reset:
TIM Channel 1 Read:
Register Low (TCH1L) Write:
See page 189. Reset:
Bit 7
Bit 7
6
Bit 6
5
Bit 5
4
Bit 4
3
Bit 3
2
Bit 2
1
Bit 1
Bit 0
Bit 0
0
0
0
0
0
0
0
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
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
1
CH0F
0
0
1
1
1
1
1
1
1
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
0
0
0
0
0
0
0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 2
Bit 1
Bit 0
Indeterminate after reset
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Indeterminate after reset
CH1F
0
0
Bit 15
0
CH1IE
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
0
0
0
0
0
0
0
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 2
Bit 1
Bit 0
Indeterminate after reset
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Indeterminate after reset
Reserved
TIM Channel 2 Status and Read:
Control Register (TSC2) Write:
See page 186. Reset:
TIM Channel 2 Read:
Register High (TCH2H) Write:
See page 189. Reset:
TIM Channel 2 Read:
Register Low (TCH2L) Write:
See page 189. Reset:
TIM Channel 3 Status and Read:
Control Register (TSC3) Write:
See page 186. Reset:
TIM Channel 3 Read:
Register High (TCH3H) Write:
See page 189. Reset:
TIM Channel 3 Read:
Register Low (TCH3L) Write:
See page 189. Reset:
CH2F
0
0
Bit 15
0
CH2IE
MS2A
ELS2B
ELS2A
TOV2
CH2MAX
0
0
0
0
0
0
0
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 2
Bit 1
Bit 0
Indeterminate after reset
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Indeterminate after reset
CH3F
0
0
Bit 15
0
CH3IE
MS3A
ELS3B
ELS3A
TOV3
CH3MAX
0
0
0
0
0
0
0
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 2
Bit 1
Bit 0
Indeterminate after reset
Bit 7
Bit 6
Bit 5
= Unimplemented
Bit 4
Bit 3
Indeterminate after reset
R
= Reserved
U = Unaffected
Figure 2-2. Control, Status, and Data Registers (Sheet 3 of 5)
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
27
Memory
Addr.
$0036
$0037
$0038
$0039
↓
$003B
$003C
$003D
$003E
$003F
$FE00
$FE01
$FE02
$FE03
$FE04
$FE05
$FE06
Register Name
Bit 7
6
Read:
Oscillator Status and
OSCOPT1 OSCOPT0
Control Register (OSCSC) Write:
See page 100. Reset:
0
0
5
4
3
2
1
Bit 0
ECGST
ICFS1
ICFS0
ECFS1
ECFS0
ECGON
0
0
0
0
0
0
Reserved
Oscillator Trim Register
(OSCTRIM)
See page 101.
Read:
Write:
TRIM7
TRIM6
TRIM5
TRIM4
TRIM3
TRIM2
TRIM1
TRIM0
Reset:
1
0
0
0
0
0
0
0
AIEN
ADCO
ADCH4
ADCH3
ADCH2
ADCH1
ADCH0
0
0
R
0
AD7
R
0
0
0
R
0
AD6
R
0
0
0
R
0
AD5
R
0
1
0
R
0
AD4
R
0
1
0
R
0
AD3
R
0
1
0
R
0
AD2
R
0
1
AD9
R
0
AD1
R
0
1
AD8
R
0
AD0
R
0
ADLPC
ADIV1
ADIV0
ADICLK
MODE1
MODE0
ADLSMP
ACLKEN
0
0
0
0
0
0
0
R
R
R
R
R
R
POR
PIN
COP
ILOP
ILAD
MODRST
0
SBSW
0
0
LVI
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BCFE
R
R
R
R
R
R
R
IF3
R
0
IF11
R
0
IF19
R
0
R
IF2
R
0
IF10
R
0
IF18
R
0
= Reserved
Reserved
ADC10 Status and Control Read:
Register (ADSCR) Write:
See page 46. Reset:
ADC10 Data Register High Read:
(ADRH) Write:
See page 48. Reset:
ADC10 Data Register Low Read:
(ADRL) Write:
See page 48. Reset:
ADC10 Clock Register Read:
(ADCLK) Write:
See page 49. Reset:
Break Status Register Read:
(BSR) Write:
See page 195. Reset:
SIM Reset Status Register Read:
(SRSR) Write:
See page 152. POR:
Break Auxiliary Read:
Register (BRKAR) Write:
See page 195. Reset:
Break Flag Control Read:
Register (BFCR) Write:
See page 195. Reset:
Interrupt Status Register 1 Read:
(INT1) Write:
See page 149. Reset:
Interrupt Status Register 2 Read:
(INT2) Write:
See page 149. Reset:
Interrupt Status Register 3 Read:
(INT3) Write:
See page 149. Reset:
COCO
0
IF6
R
0
IF14
R
0
IF22
R
0
IF5
IF4
R
R
0
0
IF13
IF12
R
R
0
0
IF21
IF20
R
R
0
0
= Unimplemented
IF1
0
R
R
0
0
IF9
IF8
R
R
0
0
IF17
IF16
R
R
0
0
U = Unaffected
R
0
0
BDCOP
0
R
0
IF7
R
0
IF15
R
0
Figure 2-2. Control, Status, and Data Registers (Sheet 4 of 5)
MC68HC908QB8 Data Sheet, Rev. 3
28
Freescale Semiconductor
Direct Page Registers
Addr.
$FE07
$FE08
$FE09
$FE0A
$FE0B
$FE0C
$FE0D
↓
$FE0F
$FFBE
$FFBF
$FFC0
$FFC1
$FFFF
Register Name
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
HVEN
MASS
ERASE
PGM
0
0
0
0
0
0
0
0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
0
0
0
0
0
0
0
0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
BRKE
BRKA
0
0
0
0
0
0
0
0
0
0
0
0
0
LVIOUT
0
0
0
0
0
0
0
0
0
0
0
0
0
R
0
0
0
0
0
0
0
0
BPR7
BPR6
BPR5
BPR4
BPR3
BPR2
BPR1
BPR0
TRIM2
TRIM1
TRIM0
Reserved
FLASH Control Register Read:
(FLCR) Write:
See page 31. Reset:
Break Address High Read:
Register (BRKH) Write:
See page 194. Reset:
Break Address low Read:
Register (BRKL) Write:
See page 194. Reset:
Break Status and Control Read:
Register (BRKSCR) Write:
See page 194. Reset:
LVI Status Register Read:
(LVISR) Write:
See page 91. Reset:
Reserved
FLASH Block Protect Read:
Register (FLBPR) Write:
See page 36. Reset:
Unaffected by reset
Reserved
Internal Oscillator Trim Read:
(Factory Programmed, Write:
VDD = 3.0 V) Reset:
TRIM7
TRIM6
TRIM5
TRIM4
TRIM3
Resets to factory programmed value
Reserved
COP Control Register Read:
(COPCTL) Write:
See page 63. Reset:
LOW BYTE OF RESET VECTOR
WRITING CLEARS COP COUNTER (ANY VALUE)
Unaffected by reset
= Unimplemented
R
= Reserved
U = Unaffected
Figure 2-2. Control, Status, and Data Registers (Sheet 5 of 5)
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
29
Memory
Table 2-1. Vector Addresses
Vector Priority
Vector
Address
Lowest
IF22–
IF16
$FFD0–
$FFDC
Not used
IF15
$FFDE,F
ADC conversion complete vector
IF14
$FFE0,1
Keyboard vector
IF13
$FFE2,3
SPI transmit vector
IF12
$FFE4,5
SPI receive vector
IF11
$FFE6,7
ESCI transmit vector
IF10
$FFE8,9
ESCI receive vector
IF9
$FFEA,B
ESCI error vector
IF8
—
IF7
$FFEE,F
TIM1 Channel 3 vector
IF6
$FFF0,1
TIM1 Channel 2 vector
IF5
$FFF2,3
TIM1 overflow vector
IF4
$FFF4,5
TIM1 Channel 1 vector
IF3
$FFF6,7
TIM1 Channel 0 vector
IF2
—
IF1
$FFFA,B
IRQ vector
—
$FFFC,D
SWI vector
—
$FFFE,F
Reset vector
Highest
Vector
Not used
Not used
2.5 Random-Access Memory (RAM)
This MCU includes static RAM. The locations in RAM below $0100 can be accessed using the more
efficient direct addressing mode, and any single bit in this area can be accessed with the bit manipulation
instructions (BCLR, BSET, BRCLR, and BRSET). Locating the most frequently accessed program
variables in this area of RAM is preferred.
The RAM retains data when the MCU is in low-power wait or stop mode. At power-on, the contents of
RAM are uninitialized. RAM data is unaffected by any reset provided that the supply voltage does not drop
below the minimum value for RAM retention.
For compatibility with older M68HC05 MCUs, the HC08 resets the stack pointer to $00FF. In the devices
that have RAM above $00FF, it is usually best to reinitialize the stack pointer to the top of the RAM so the
direct page RAM can be used for frequently accessed RAM variables and bit-addressable program
variables. Include the following 2-instruction sequence in your reset initialization routine (where RamLast
is equated to the highest address of the RAM).
LDHX
TXS
#RamLast+1
;point one past RAM
;SP