SH7708 Datasheet, PDF (197/625 Pages) Renesas Technology Corp – SuperH™ RISC engine

9.10.5 Usage Notes
WTCNT should be set as shown below when using the SH7708 WDT in watchdog timer mode or
interval timer mode.
(a)
WTCNT setting
WTCNT =
No
set value + 1?
Yes
SLEEP instruction
(b)
WTCNT setting
Wait for 2 WDT
count clock cycles
SLEEP instruction
Perform either processing (a) or
processing (b). No processing is
required when the WDT is not used
(WTCSR.TME = 0). If this
processing is not performed, the
WDT count will stop in sleep mode.
(a) Read WTCNT and confirm that
it has been incremented, then
execute a SLEEP instruction.
(b) Wait for two WDT count clock
cycles after WTCNT is set, then
execute a SLEEP instruction.
Figure 9.6 To Operate the WDT in Sleep Mode
(a)
WTCNT setting
WTCNT =
No
set value + 1?
Yes
WTNCT instruction
(b)
WTCNT setting
Wait for 2 WDT
count clock cycles
WTCNT instruction
Perform either processing (a) or
processing (b). No processing is
required when the WDT is not used
(WTCSR.TME = 0). If this
processing is not performed, the
second WTCNT setting may not be
carried out.
(a)
After the first WTCNT setting,
read WTCNT and confirm that it
has been incremented, then
perform the next WTCNT
setting.
(b)
After the first WTCNT setting,
wait for two WDT count clock
Figure 9.7 To Perform Repeated WTCNT Settings
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