SONIX SN8P2624 - Page 72

SN8P2624
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD Page 72 Version 0.3
Watchdog timer application note is as following.
z Before clearing watchdog timer, check I/O status and check RAM contents can improve system error.
z Don’t clear watchdog timer in interrupt vector and interrupt service routine. That can improve main routine fail.
z Clearing watchdog timer program is only at one part of the program. This way is the best structure to enhance the
watchdog timer function.
¾ Example: An operation of watchdog timer is as following. To clear the watchdog timer counter in the top
of the main routine of the program.
Main:
… ; Check I/O.
… ; Check RAM
Err: JMP $ ; I/O or RAM error. Program jump here and don’t
; clear watchdog. Wait watchdog timer overflow to reset IC.
Correct: ; I/O and RAM are correct. Clear watchdog timer and
; execute program.
B0BSET FWDRST ; Only one clearing watchdog timer of whole program.
…
CALL SUB1
CALL SUB2
…
…
…
JMP MAIN