HD64F38602R Datasheet, PDF (241/552 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

Section 12 Watchdog Timer
12.3.2 Interval Timer Mode
Figure 12.3 shows the operation in interval timer mode. To use the WDT as an interval timer, set
the WT/IT bit in TCSRWD2 to 1.
When the WDT is used as an interval timer, an interval timer interrupt request is generated each
time the TCWD overflows. Therefore, an interval timer interrupt can be generated at intervals.
H'FF
TCWD
count value
H'00
Time
WT/IT = 1
Interval timer
Interval timer
Interval timer
Interval timer
Interval timer
interrupt
interrupt
interrupt
interrupt
interrupt
request generated request generated request generated request generated request generated
Figure 12.3 Interval Timer Mode Operation
12.3.3 Timing of Overflow Flag (OVF) Setting
Figure 12.4 shows the timing of the OVF flag setting. The OVF flag in TCSRWD2 is set to 1 if
TCWD overflows. At the same time, a reset signal is output in watchdog timer mode and an
interval timer interrupt is generated in interval timer mode.
φ
TCWD
Overflow signal
H'FF
H'00
OVF
Figure 12.4 Timing of OVF Flag Setting
Rev. 3.00 May 15, 2007 Page 209 of 518
REJ09B0152-0300