Interval Timer Mode - Renesas H8S/2100 Series Hardware Manual

14.4.2

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 14.3. 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 flag of TCSR is set to 1. The timing is shown figure 14.4.
TCNT value
H'FF
H'00
WT/IT = 0
TME = 1
WOVI: Interval timer interrupt request occurrence
φ
TCNT
Overflow signal
(internal signal)
OVF
Overflow Overflow
WOVI
Figure 14.3 Interval Timer Mode Operation
H'FF
Figure 14.4 OVF Flag Set Timing
Section 14 Watchdog Timer (WDT)
Overflow
WOVI WOVI
Rev. 1.00 Apr. 28, 2008 Page 399 of 994
Overflow
Time
WOVI
H'00
REJ09B0452-0100