Interval Timer Mode; Figure 15.3 Interval Timer Mode Operation; Figure 15.4 Ovf Flag Set Timing - Renesas H8S/2437 Hardware Manual

15.3.2

Interval Timer Mode

When the WDT is used as an interval timer, an interval timer interrupt (WOVI) is generated each
time TCNT overflows, as shown in figure 15.3. Therefore, an interrupt can be generated at
intervals.
When TCNT overflows in interval timer mode, the OVF bit in TCSR is set to 1 and at the same
time an interval timer interrupt (WOVI) is requested. The timing is shown in figure 15.4.
TCNT value
H'FF
H'00
WT/ = 0
TME = 1
[Legend]
WOVI : Interval timer interrupt request occurrence
φ
TCNT
Overflow signal
(internal signal)
OVF
Overflow Overflow
WOVI

Figure 15.3 Interval Timer Mode Operation

H'FF

Figure 15.4 OVF Flag Set Timing

Overflow
WOVI WOVI
Rev. 1.00, 09/03, page 421 of 704
Overflow
Time
WOVI
H'00