Interval Timer Operation - Renesas H8/3067 Series User Manual

Section 12 Watchdog Timer
H'FF
TCNT count
value
H'00
Internal
reset signal
RESO
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
IT
WT/ = 0
TME = 1
Rev. 4.00 Jan 26, 2006 page 472 of 938
REJ09B0276-0400
Start H'00 written
in TCNT
Figure 12.4 Operation in Watchdog Timer Mode
Interval Interval
timer timer
interrupt interrupt
Figure 12.5 Interval Timer Operation
WDT overflow
TME set to 1
OVF = 1
Reset
518 states
132 states
Interval Interval
timer timer
interrupt interrupt
H'00 written
in TCNT
Time t