tmp89fm42a TOSHIBA Semiconductor CORPORATION, tmp89fm42a Datasheet - Page 104

• Manufacturer Part Number: tmp89fm42a
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

RA000
8-bit up counter value
When WDCTR<WDTW> is “10”
Writing of 4EH (clear code)
Reading of WDST
Watchdog timer interrupt
request signal
WDST<WINTST1>
WDST<WINTST2>
for releasing the 8-bit up counter outside the clear time.
WDST<WINTST2> and WDST<WINTST1> in the watchdog timer interrupt service routine.
same time as the condition for turning WDST<WINTST2> or WDST<WINTST1> to "1" is satisfied,
WDST<WINTST2> or WDST<WINTST1> is set to "1", rather than being cleared.
WDST<WINTST1> is set to "1" when a watchdog timer interrupt request signal occurs due to the operation
You can know which factor has caused a watchdog timer interrupt request signal by reading
WDST<WINTST2> and WDST<WINTST1> are cleared to "0" when WDST is read. If WDST is read at the
0xFF 0x00 0x01
Figure 5-4 Changes in the Watchdog Timer Status
Interrupt request signal generated by clearing
the 8-bit up counter outside the clear time
Outside the clear time
0x3F
0x40
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0x7F 0x80
0xBF 0xC0
Clear time
0xFF 0x00
Interrupt request signal generated by the
overflow of the 8-bit up counter
0x01
TMP89FM42A