CHAPTER 9 WATCHDOG TIMER
User’s Manual U17446EJ3V1UD
158
(2) When the watchdog timer operation clock is the low-speed internal oscillation clock (f
RL
) when the STOP
instruction is executed
When the STOP instruction is executed, operation of the watchdog timer is stopped. After STOP mode is
released, operation stops for 34
μ
s (TYP.) and then 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 9-7. Operation in STOP Mode (WDT Operation Clock: Low-Speed Internal Oscillation Clock)
<1> CPU clock: Crystal/ceramic oscillation clock
Operating
Oscillation stabilization time
Normal operation
Oscillation stabilization time
(set by OSTS register)
Watchdog timer
Operation stopped
Operating
f
RL
f
CPU
CPU operation
Normal
operation
STOP
Oscillation stopped
Operation
stopped
Note
<2> CPU clock: High-speed internal oscillation clock or external clock input
Operating
Normal operation
Watchdog timer
Operation stopped
Operating
f
RL
f
CPU
CPU operation
Normal
operation
STOP
Oscillation stopped
Operation
stopped
Note
Note
The operation stop time is 17
μ
s (MIN.), 34
μ
s (TYP.), and 67
μ
s (MAX.).