Datasheet

Section 11 Watchdog Timer
Rev.7.00 Feb. 14, 2007 page 425 of 1108
REJ09B0089-0700
11.3.2 Operation in Interval Timer Mode
To use the WDT as an interval timer, clear the WT/IT bit in TCSR to 0 and set the TME bit to 1.
An interval timer interrupt (WOVI) is generated each time TCNT overflows, provided that the
WDT is operating as an interval timer, as shown in figure 11.5. This function can be used to
generate interrupt requests at regular intervals.
TCNT count
H'00
Time
H'FF
WT/IT=0
TME=1
WOVI
Overflow Overflow Overflow Overflow
Legend
WOVI: Interval timer interrupt request generation
WOVI WOVI WOVI
Figure 11.5 Operation in Interval Timer Mode