Datasheet

Section 13 Watchdog Timer
Rev.6.00 Sep. 27, 2007 Page 594 of 1268
REJ09B0220-0600
13.4 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.
13.5 Usage Notes
13.5.1 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 13.8 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 13.8 Contention between TCNT Write and Increment