HD64F3039F18 Datasheet, PDF (351/710 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family / H8/300H Series

Section 10 Watchdog Timer
H'FF
TCNT count
value
H'00
Internal
reset signal
Start
WDT overflow
TME set to 1
OVF = 1
H'00 written
in TCNT
Reset
H'00 written
in TCNT
RESO
518 states
132 states
Figure 10.4 Watchdog Timer Operation (Mask ROM Version)
10.3.2 Interval Timer Operation
Figure 10.5 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
Time t
WT/ IT = 0
TME = 1
Interval
timer
interrupt
Interval
timer
interrupt
Interval
timer
interrupt
Interval
timer
interrupt
Figure 10.5 Interval Timer Operation
Interval
timer
interrupt
Rev.3.00 Mar. 26, 2007 Page 327 of 682
REJ09B0353-0300