188
CHAPTER 12 HARDWARE WATCHDOG TIMER
12.4
Explanation of Hardware Watchdog Timer Operations and
Setup Procedure Example
The hardware watchdog timer generates a hardware watchdog reset when the hardware
watchdog timer counter overflows.
■
Operations of Hardware Watchdog Timer
●
How to activate the hardware watchdog timer
•
The timer of the hardware watchdog timer is activated after reset.
•
A reset is the only way to stop its operation.
●
Clearing the hardware watchdog timer
•
When the counter of the hardware watchdog timer is not cleared within the interval time, it overflows,
allowing the hardware watchdog timer to generate a hardware watchdog reset.
•
The counter of the hardware watchdog timer is cleared when "0101
B
" is written to the hardware
watchdog control bits of the watchdog timer control register (HWDC:WTE3 to WTE0) for the second or
any succeeding time.
•
The hardware watchdog timer is cleared at the same time as the timer selected as the count clock (from
RC oscillator prescalar) is cleared.
●
Operation in standby mode
Regardless of the clock mode selected, the hardware watchdog timer clears its counter and stops the
operation when entering a standby mode (sleep/stop/timebase timer/watch).
Once released from the standby mode, the timer restarts the operation.
Note:
The hardware watchdog timer is also cleared when the RC oscillator prescalar is cleared.
For this reason, the hardware watchdog timer cannot function as such, if the software is set to
clear the RC oscillator prescalar repeatedly during the interval time of the hardware watchdog
timer.
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: ......