Datasheet

Section 11 Watchdog Timer
Rev.7.00 Feb. 14, 2007 page 428 of 1108
REJ09B0089-0700
11.4 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.
11.5 Usage Notes
11.5.1 Contention between Timer Counter (TCNT) Write and Increment
If a timer counter clock pulse is generated during the T
2
state of a TCNT write cycle, the write
takes priority and the timer counter is not incremented. Figure 11.8 shows this operation.
A
ddress
φ
Internal write signal
TCNT input clock
TCNT
NM
T
1
T
2
TCNT write cycle
Counter write data
Figure 11.8 Contention between TCNT Write and Increment