CHAPTER 9 WATCHDOG TIMER
User’s Manual U16898EJ3V0UD
155
9.4.4
Watchdog timer operation in HALT mode (when “low-speed internal oscillator can be stopped by
software” is selected by option byte)
The watchdog timer stops counting during HALT instruction execution regardless of whether the operation clock of
the watchdog timer is the system clock (f
X
) or low-speed internal oscillation clock (f
RL
). After HALT mode is released,
counting is started again using the operation clock before the operation was stopped. At this time, the counter is not
cleared to 0 but holds its value.
Figure 9-8. Operation in HALT Mode
Watchdog timer
Operating
f
X
or f
RL
f
CPU
CPU operation
Normal operation
Operating
HALT
Operation stopped
Normal operation