208
CHAPTER 6 Watchdog timer
6.1
Overview of Watchdog Timer
The watchdog timer is a 2-bit counter that uses the timebase timer or watch timer as a
count clock.If the counter is not cleared within a set interval time, the CPU is reset.
■
Functions of Watchdog Timer
•
The watchdog timer is a timer counter that is used to prevent program malfunction.When the watchdog
timer is started, the watchdog timer counter must continue to be cleared within a set interval time.If the
set time interval is reached without clearing the watchdog timer counter, the CPU is reset. This is called
watchdog timer
•
The interval time of the watchdog timer depends on the clock cycle input as a count clock and a
watchdog reset occurs between the minimum and maximum times.
•
The clock source output destination is set by the watchdog clock select bit in the watch timer control
register (WTC: WDCS).
•
The interval time of the watchdog timer is set by the timebase timer output select bit/watch timer output
select bit in the watchdog timer control register (WDTC: WT1, WT0).
Table 6.1-1 lists the interval times of the watchdog timer.
Table 6.1-1 Interval Time of Watchdog Timer
Min.
Max.
Clock Cycle
Min.
Max.
Clock Cycle
Approx. 3.58
ms
Approx. 4.61
ms
2
14
±
2
11
/HCLK
Approx.
0.457 s
Approx.
0.576 s
2
12
±
2
9
/SCLK
Approx.
14.33 ms
Approx. 18.3
ms
2
16
±
2
13
/HCLK
Approx.
3.584 s
Approx.
4.608 s
2
15
±
2
12
/SCLK
Approx.
57.23 ms
Approx.
73.73 ms
2
18
±
2
15
/HCLK
Approx.
7.168 s
Approx.
9.216 s
2
16
±
2
13
/SCLK
Approx.
458.75 ms
Approx.
589.82 ms
2
21
±
2
18
/HCLK
Approx.
14.336 s
Approx.
18.432 s
2
17
±
2
14
/SCLK
HCLK: Oscillation clock (4 MHz), SLCK: Sub clock (8.192 kHz)
Notes:
•
When the timebase timer output (carry signal) is used as a count clock to the watchdog
timer, clearing the timebase timer may extend the time for a watchdog reset to occur.
•
When the subclock is used as the machine cock, be sure to set the watchdog timer clock
source select bit (WDCS) in the watch timer control register (WTC) to "0" to select the
watch timer output.
Содержание F2MC-16LX Series
Страница 2: ......
Страница 3: ...FUJITSU LIMITED F2MC 16LX 16 bit Microcontroller MB90895 series Hardware Manual ...
Страница 4: ......
Страница 8: ...iv ...
Страница 10: ...vi ...
Страница 36: ...18 CHAPTER 2 HANDLING DEVICES ...
Страница 176: ...158 CHAPTER 3 CPU ...
Страница 224: ...206 CHAPTER 5 Timebase timer ...
Страница 294: ...276 CHAPTER 8 16 bit reload timer ...
Страница 366: ...348 CHAPTER 12 DTP external interrupt ...
Страница 398: ...380 CHAPTER 13 8 10 bit A D converter ...
Страница 446: ...428 CHAPTER 14 UART0 ...
Страница 588: ...570 CHAPTER 17 Address Match Detecting Function ...
Страница 626: ...608 CHAPTER 19 512 KBIT FLASH MEMORY ...
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 ...
Страница 710: ......