Datasheet

Section 10 Watchdog Timer (WDT)
Rev.7.00 Dec. 24, 2008 Page 345 of 698
REJ09B0074-0700
10.3.4 Timing of Setting of 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 10.5.
φ
TCNT H'FF H'00
Overflow signal
(internal signal)
OVF
Figure 10.5 Timing of OVF Setting
10.4 Interrupts
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. OVF must be
cleared to 0 in the interrupt handling routine.
Table 10.1 WDT Interrupt Source
Name Interrupt Source Interrupt Flag
WOVI TCNT overflow WOVF