HD64F3048F16 Datasheet, PDF (478/903 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 12 Watchdog Timer
12.3.2 Interval Timer Operation
Figure 12.5 illustrates interval timer operation. To use the WDT as an interval timer, clear bit
WT/IT to 0 and set bit TME to 1 in TCSR. An interval timer interrupt request is generated at each
TCNT overflow. This function can be used to generate interval timer interrupts at regular
intervals.
H'FF
TCNT
count value
H'00
WT/ IT = 0
TME = 1
Interval
timer
interrupt
Interval
timer
interrupt
Interval
timer
interrupt
Interval
timer
interrupt
Figure 12.5 Interval Timer Operation
Time t
12.3.3 Timing of Setting of Overflow Flag (OVF)
Figure 12.6 shows the timing of setting of the OVF flag in TCSR. The OVF flag is set to 1 when
TCNT overflows. At the same time, a reset signal is generated in watchdog timer operation, or an
interval timer interrupt is generated in interval timer operation.
φ
TCNT
H'FF
H'00
Overflow signal
OVF
Figure 12.6 Timing of Setting of OVF
Rev. 3.00 Sep 27, 2006 page 450 of 872
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