Interval Timer Mode; Figure 15.3 Interval Timer Mode Operation; Figure 15.4 Ovf Flag Set Timing - Renesas H8S/2158 User Manual

15.4.2

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 15.3. 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 15.4.
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 15.3 Interval Timer Mode Operation

H'FF

Figure 15.4 OVF Flag Set Timing

Section 15 Watchdog Timer (WDT)
Overflow Overflow
WOVI WOVI
H'00
Rev. 3.00 Jan 25, 2006 page 381 of 872
Time
REJ09B0286-0300