180
CHAPTER 11 WATCHDOG TIMER
11.5
Precautions when Using Watchdog Timer
Care must be taken for the following points when using the watchdog timer.
■
Precautions when Using Watchdog Timer
●
Stopping the watchdog timer
Once activated, the watchdog timer cannot be stopped until a reset is generated.
●
Selecting the count clock
The count clock switch bits (WDTC:CS1,0) can be rewritten only when the watchdog control bits
(WDTC:WTE3 to WTE0) are set to "0101
B
" upon the activation of the watchdog timer. The count clock
switch bits cannot be written by a bit operation instruction. Moreover, the bit settings should not be
changed once the timer is activated.
In the subclock mode, the timebase timer does not operate because the main clock stops oscillating.
In order to operate the watchdog timer in the subclock mode, it is necessary to select the watch prescaler as
the count clock beforehand and set "WDTC:CS1,0" to "10
B
" or "11
B
".
●
Clearing the watchdog timer
Clearing the counter used for the count clock of the watchdog timer (timebase timer or watch prescaler)
also clears the counter of the watchdog timer.
The counter of the watchdog timer is cleared when entering the sleep mode, stop mode or watch mode.
●
Programming precaution
When creating a program in which the watchdog timer is cleared repeatedly in the main loop, set the
processing time of the main loop including the interrupt processing time to the minimum watchdog timer
interval time or shorter.
Summary of Contents for F2 MC-8FX Family
Page 2: ......
Page 4: ......
Page 34: ...20 CHAPTER 1 DESCRIPTION ...
Page 38: ...24 CHAPTER 2 HANDLING DEVICES ...
Page 39: ...25 CHAPTER 3 MEMORY SPACE This chapter describes memory space 3 1 Memory Space 3 2 Memory Map ...
Page 56: ...42 CHAPTER 5 CPU ...
Page 73: ...59 CHAPTER 6 CLOCK CONTROLLER ...
Page 96: ...82 CHAPTER 6 CLOCK CONTROLLER ...
Page 104: ...90 CHAPTER 7 RESET ...
Page 105: ...91 CHAPTER 8 INTERRUPTS This chapter explains the interrupts 8 1 Interrupts ...
Page 174: ...160 CHAPTER 10 TIMEBASE TIMER ...
Page 184: ...170 CHAPTER 10 TIMEBASE TIMER ...
Page 218: ...204 CHAPTER 13 WATCH PRESCALER ...
Page 257: ...243 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 261: ...247 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 288: ...274 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 301: ...287 CHAPTER 17 16 BIT PPG TIMER ...
Page 316: ...302 CHAPTER 17 16 BIT PPG TIMER ...
Page 382: ...368 CHAPTER 21 UART SIO DEDICATED BAUD RATE GENERATOR ...
Page 390: ...376 CHAPTER 22 I2C ...
Page 395: ...381 CHAPTER 22 I2C ...
Page 399: ...385 CHAPTER 22 I2C ...
Page 430: ...416 CHAPTER 23 10 BIT A D CONVERTER ...
Page 476: ...462 CHAPTER 24 LCD CONTROLLER ...
Page 482: ...468 CHAPTER 25 LOW VOLTAGE DETECTION RESET CIRCUIT ...
Page 494: ...480 CHAPTER 26 CLOCK SUPERVISOR ...
Page 507: ...493 CHAPTER 27 REAL TIME CLOCK ...
Page 523: ...509 CHAPTER 27 REAL TIME CLOCK ...
Page 532: ...518 CHAPTER 27 REAL TIME CLOCK ...
Page 536: ...522 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 554: ...540 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 564: ...550 CHAPTER 29 EXAMPLE OF SERIAL PROGRAMMING CONNECTION ...
Page 595: ...581 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 596: ...582 INDEX Index ...
Page 597: ...583 INDEX ...
Page 600: ...586 Pin Function Index ...
Page 602: ......