R01UH0823EJ0100 Rev.1.00
Page 828 of 1823
Jul 31, 2019
RX23W Group
30. Watchdog Timer (WDTA)
Figure 30.3
Operation Example in Register Start Mode
Refresh-
prohibited
period
(1)
(2)
(2)
(2)
(1) Initial value
(2) Set value
Writing to the
register is invalid.
Status flag
cleared
Status flag
cleared
Counter value
Refresh-
permitted
period
Refresh-
prohibited
period
100%
75%
50%
25%
0%
RES# pin
WDTCR
register
Refresh
the counter
Active: High
REFEF flag
Active: High
UNDFF flag
Active: High
Reset output
from WDT
Active: High
Counting starts
Counting starts
Counting starts
Writing to the
register is invalid.
Writing to the
register is valid.
Interrupt request
(WUNI)
Active: Low
H
L
H
L
H
L
H
L
H
Underflow
Refresh error
Refresh error