HD64F2168 Datasheet, PDF (385/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

13.4.2 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 13.3. 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 13.4.
TCNT value
H'FF
Overflow
Overflow
Overflow
Overflow
H'00
WT/IT = 0
TME = 1
WOVI
WOVI
WOVI
WOVI
Time
WOVI : Interval timer interrupt request occurrence
Figure 13.3 Interval Timer Mode Operation
φ
TCNT
Overflow signal
(internal signal)
OVF
H'FF
H'00
Figure 13.4 OVF Flag Set Timing
Rev. 3.00, 03/04, page 345 of 830