CHAPTER 10 WATCHDOG TIMER
Preliminary User’s Manual U16315EJ1V0UD
210
Table 10-2. Mask Option Setting and Watchdog Timer Operation Mode
Mask Option
Ring-OSC Cannot Be Stopped
Ring-OSC Can Be Stopped by Software
Watchdog timer clock
source
Fixed to f
R
Note 1
.
•
Selectable by software (f
XP
, f
R
or
stopped)
•
When reset is released: f
R
Operation after reset
Operation starts with the maximum
interval (f
R
/2
18
).
Operation starts with maximum
interval (f
R
/2
18
).
Operation mode selection
The interval can be changed only
once.
The clock selection/interval can be
changed only once.
Features
•
The watchdog timer cannot be
stopped.
•
Current in STOP mode
≅
10
µ
A
The watchdog timer can be stopped in
standby mode
Note 2
.
Notes 1.
As long as power is being supplied, Ring-OSC oscillation cannot be stopped (except in the reset
period).
2.
Clock supply to the watchdog timer is stopped in accordance with the watchdog timer clock
source as follows:
<1> When the clock source is f
XP
Clock supply to the watchdog timer is stopped while f
XP
is stopped, during HALT/STOP
instruction execution, and during the oscillation stabilization time.
<2> When the clock source is f
R
Clock supply to the watchdog timer is stopped if f
R
is stopped by software before STOP
instruction execution when the CPU clock is f
XP
and during HALT/STOP instruction
execution.
Remarks 1.
f
R
: Ring-OSC clock oscillation frequency
2.
f
XP
: X1 input clock oscillation frequency