t81l0003a TM Technology Inc., t81l0003a Datasheet - Page 14

• Manufacturer Part Number: t81l0003a
• Description: Reduced I/o 8-bit Mcu
• Manufacturer: TM Technology Inc.

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T81L0003A
Watchdog Timer
The watchdog timer is a 16-bit counter that is incremented once every 24 or 384 clock cycles. After an external reset the
watchdog timer is disabled and all registers are set to zeros.
! Watchdog Timer structure
The watchdog consists of 16-bit counter wdt, reload register wdtrel, prescalers by 2 and by 16 and control logic. Where
wdtl=00h while start up.
Figure
Watchdog block diagram
! Start procedure
There are one way to start the watchdog. A programmer can start the watchdog as refreshing procedure. Once the
watchdog is started it cannot be stopped unless rst signal becomes active. When wdt registers enters the state 7FFCh,
asynchronous wdts signal will become active. The signal wdts sets the bit 6 in ip0 register and requests reset state. The
wdts is cleared either by rst signal or change of the state of the wdt timer.
Procedure: load wdtrel value # # # # set “wdt” # # # # set “swdt” in 12 instruction cycles.
TM Technology, Inc. reserves the right
P. 14
Publication Date: SEP. 2004
to change products or specifications without notice.
Revision: C