Interval Timer Mode; Interrupt Source; Figure 11.3 Operation In Interval Timer Mode; Table 11.1 Wdt Interrupt Source - Renesas H8SX/1520 Series Hardware Manual

11.3.2

Interval Timer Mode

To use the WDT as an interval timer, set the WT/IT bit to 0 and the TME bit to 1 in TCSR.
When the WDT is used as an interval timer, an interval timer interrupt (WOVI) is generated each
time the TCNT overflows. 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 in the TCSR is set to 1.
H'FF
H'00
11.4

Interrupt Source

During interval timer mode operation, an overflow generates an interval timer interrupt (WOVI).
The interval timer interrupt is requested whenever the OVF flag is set to 1 in TCSR. The OVF flag
must be cleared to 0 in the interrupt handling routine.

Table 11.1 WDT Interrupt Source

Name
WOVI
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TCNT value
Overflow
WOVI
WT/IT = 0
TME = 1
WOVI: Interval timer interrupt request

Figure 11.3 Operation in Interval Timer Mode

Interrupt Source
TCNT overflow
Section 11 Watchdog Timer (WDT)
Overflow Overflow
WOVI WOVI
Interrupt Flag
OVF
Rev. 3.00 Mar. 14, 2006 Page 373 of 804
Overflow
Time
WOVI
DMAC Activation
Impossible
REJ09B0104-0300