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H'FF
TCNT
count
H'00
13.3.2 Interval Timer Mode
Interval timer operation begins when the WT/IT bit is cleared to 0 and the TME bit is set to 1.
In the interval timer mode, an IRQ
This function can be used to generate IRQ
IRQ
requests from the watchdog timer module have the same vector as IRQ
0
IRQ
pin, so the IRQ
0
determine the source of the interrupt.
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WT/IT = 1
TIME = 1
Figure 13-3 Operation in Watchdog Timer Mode
request is generated each time the timer count overflows.
0
interrupt-handling routine must check the OVF bit in the TCSR to
0
H'00 written
to TCNT
requests at regular intervals. See figure 13-4.
0
241
Time t
OVF = 1
NMI requested
requests from the
0
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