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CHAPTER 10 WATCHDOG TIMER
10.5 Notes on Using Watchdog Timer
This section explains notes on using the watchdog timer.
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Notes on using watchdog timer
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Stopping the watchdog timer
The watchdog timer stops by all reset causes.
❍
Interval time
Because the interval time uses the carry signals of the timebase timer as the count clock, the
interval time of the watchdog timer may become longer than the specified time when the
timebase timer is cleared.
The timebase timer is also cleared by writing "0" to the TBR bit in the timebase timer control
register (TBTC), transition from main clock mode to PLL clock mode, transition from sub-clock
mode to main clock mode, and transition from sub-clock mode to PLL clock mode.
❍
Selection of the interval time
The interval time can be specified when the watchdog timer is started. Any data written after the
start of the watchdog timer is ignored.
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Caution on creating programs
When creating a program that clears the watchdog timer repetitively in the main loop, the main
loop processing time, including interrupt processing, must be less than the minimum interval
time of the watchdog timer.
❍
Caution at sub-clock mode
Please select the output of the clock timer by setting the watchdog timer clock source selection
bit (WDCS) of the clock timer control register (WTC) to "0" on subclock mode.
Summary of Contents for MB90480 Series
Page 2: ......
Page 4: ......
Page 10: ...vi ...
Page 128: ...106 CHAPTER 4 RESET ...
Page 174: ...152 CHAPTER 6 LOW POWER CONSUMPTION MODE ...
Page 198: ...176 CHAPTER 7 MODE SETTING ...
Page 220: ...198 CHAPTER 9 TIMEBASE TIMER ...
Page 238: ...216 CHAPTER 11 WATCH TIMER ...
Page 280: ...258 CHAPTER 12 16 BIT INPUT OUTPUT TIMER ...
Page 406: ...384 CHAPTER 17 8 10 BIT A D CONVERTER ...
Page 478: ...456 CHAPTER 20 CHIP SELECTION FACILITY ...
Page 494: ...472 CHAPTER 21 ADDRESS MATCH DETECTION FUNCTION ...
Page 498: ...476 CHAPTER 22 ROM MIRROR FUNCTION SELECTION MODULE ...
Page 526: ...504 CHAPTER 23 2M 3M BIT FLASH MEMORY ...
Page 536: ...514 CHAPTER 24 EXAMPLES OF MB90F481B MB90F482B MB90F488B MB90F489B SERIAL PROGRAMMING ...
Page 570: ...548 CHAPTER 25 PWC TIMER ONLY MB90485 SERIES ...
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