CHAPTER 9 WATCHDOG TIMER
Preliminary User’s Manual U19014EJ1V0UD
222
9.4.3 Setting window open period of watchdog timer
In the
µ
PD78F0730, the window open period of the watchdog timer is 100%. Do not set any values other than 1, 1
(default) to bits 6 and 5 (WINDOW1, WINDOW0) of the option byte.
Whenever WDTE is written to during the window open period (100%), as long as it is before the overflow time, the
watchdog timer is cleared and starts counting again.
Window open period (100%)
Counting
starts
Overflow
time
Counting starts again when
“ACH” is written to WDTE.
The window open period to be set is as follows.
Table 9-4. Setting Window Open Period of Watchdog Timer
WINDOW1
WINDOW0
Window Open Period of Watchdog Timer
0 0
Setting
prohibited
0 1
Setting
prohibited
1 0
Setting
prohibited
1 1
100%
(default)
Caution Only the combination of WINDOW1 and WINDOW0 = 1, 1 is valid. Other settings are
prohibited.
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