Interval Timer Mode; Figure 11.3 Interval Timer Mode Operation; Figure 11.4 Ovf Flag Set Timing - Renesas H8S/2111B Hardware Manual

11.4.2

Interval Timer Mode

When the WDT is used as an interval timer, an interval timer interrupt (WOVI) is generated each
time the TCNT overflows, as shown in figure 11.3. Therefore, an interrupt can be generated at
intervals.
When the TCNT overflows in interval timer mode, an interval timer interrupt (WOVI) is requested
at the same time the OVF bit of TCSR is set to 1. The timing is shown figure 11.4.
TCNT value
H'FF
H'00
WT/IT = 0
TME = 1
[Legend]
WOVI : Internal timer interrupt request occurrence
φ
TCNT
Overflow signal
(internal signal)
OVF
Overflow Overflow
WOVI WOVI

Figure 11.3 Interval Timer Mode Operation

H'FF

Figure 11.4 OVF Flag Set Timing

Overflow Overflow
WOVI WOVI
H'00
Rev. 1.00, 05/04, page 229 of 544
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