286
CHAPTER 9 Watch timer
9.5
Explanation of Operation of Watch Timer
The watch timer operates as an interval timer or an oscillation stabilization wait time
timer of the sub clock.It also supplies an operation clock to the watchdog timer.
■
Watch timer counter
The watch timer counter continues incrementing in synchronization with the sub clock (SCLK) while the
sub clock (SCLK) is operating.
●
Clearing watch timer counter
The watch timer counter is cleared to "0000
H
" when:
•
Power on reset
•
The mode transits to the stop mode.
•
The watch timer clear bit (WTR) in the watch timer control register (WTC) is set to 0.
■
Interval Timer Function
The watch timer can be used as an interval timer by generating an interrupt at each interval time.
●
Settings when using watch timer as interval timer
Operating the watch timer as an interval timer requires the settings shown in Figure 9.5-1.
Figure 9.5-1 Setting of Watch Timer
•
When the value set by the interval time select bits (WTC1, WTC0) in the watch timer control register
(WTC) is reached, the overflow flag bit in the WTC register is set to 1 (WTC: WTOF = 1).
•
When the overflow flag bit is set (WTC: WTOF = 1) with the overflow interrupt of the watch timer
counter enabled (WTC: WTIE = 1), an interrupt request is generated.
Note:
When the watch timer counter is cleared, the interrupts of the watchdog timer and interval
timer that use the output of the watch timer counter are affected.
Before clearing the watch timer by setting the watch timer clear bit (WTR) in the watch timer
control register (WTC), set the overflow interrupt enable bit (WTIE) in the WTC register to
disable the watch timer for interrupts.Before enabling interrupts, set the WTC overflow flag
bit (WTOF) to clear the interrupt request.
WTC
6
5
4
3
2
1
: Unused bit
: Used bit
WTOF WTR
WTC1
WTC2
SCE WTIE
WTC0
WDCS
bit7
bit0
Содержание F2MC-16LX Series
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Страница 224: ...206 CHAPTER 5 Timebase timer ...
Страница 294: ...276 CHAPTER 8 16 bit reload timer ...
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Страница 676: ...658 APPENDIX Table A 9 3 Bit Operation Instruction Map first byte 6CH ...
Страница 677: ...659 APPENDIX A Instructions Table A 9 4 Character String Operation Instruction Map first byte 6EH ...
Страница 678: ...660 APPENDIX Table A 9 5 2 byte Instruction Map first byte 6FH MUL MULW DIVU A A A ...
Страница 680: ...662 APPENDIX Table A 9 7 ea Instruction 2 first byte 71H ...
Страница 681: ...663 APPENDIX A Instructions Table A 9 8 ea Instruction 3 first byte 72H ...
Страница 682: ...664 APPENDIX Table A 9 9 ea Instruction 4 first byte 73H ...
Страница 683: ...665 APPENDIX A Instructions Table A 9 10 ea Instruction 5 first byte 74H ...
Страница 684: ...666 APPENDIX Table A 9 11 ea Instruction 6 first byte 75H ...
Страница 685: ...667 APPENDIX A Instructions Table A 9 12 ea Instruction 7 first byte 76H ...
Страница 686: ...668 APPENDIX Table A 9 13 ea Instruction 8 first byte 77H ...
Страница 687: ...669 APPENDIX A Instructions Table A 9 14 ea Instruction 9 first byte 78H ...
Страница 688: ...670 APPENDIX Table A 9 15 MOVEA RWi ea Instruction first byte 79H ...
Страница 689: ...671 APPENDIX A Instructions Table A 9 16 MOV Ri ea Instruction first byte 7AH ...
Страница 690: ...672 APPENDIX Table A 9 17 MOVW RWi ea Instruction first byte 7BH ...
Страница 691: ...673 APPENDIX A Instructions Table A 9 18 MOV ea Ri Instruction first byte 7CH ...
Страница 692: ...674 APPENDIX Table A 9 19 MOVW ea Rwi Instruction first byte 7DH ...
Страница 693: ...675 APPENDIX A Instructions Table A 9 20 XCH Ri ea Instruction first byte 7EH ...
Страница 694: ...676 APPENDIX Table A 9 21 XCHW RWi ea Instruction first byte 7FH ...
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