HD64F2357F20V Datasheet, PDF (491/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

13.3.2 Interval Timer Operation
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 13-5. This function can be used to generate interrupt requests at regular intervals.
TCNT count
H'FF
Overflow
Overflow
Overflow
Overflow
H'00
WT/IT=0
TME=1
WOVI
WOVI
WOVI
Legend:
WOVI: Interval timer interrupt request generation
Figure 13-5 Interval Timer Operation
WOVI
Time
13.3.3 Timing of Setting Overflow Flag (OVF)
The OVF flag is set to 1 if TCNT overflows during interval timer operation. At the same time, an interval timer interrupt
(WOVI) is requested. This timing is shown in figure 13-6.
ø
TCNT
Overflow signal
(internal signal)
H'FF
H'00
OVF
Figure 13-6 Timing of Setting of OVF
Rev.6.00 Oct.28.2004 page 461 of 1016
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