Peak 555A User’s Guide
Watch Dog Timer A-4
An Example
a. Enable watchdog timer
b. Select I/O port F2 & set WDT timer at 1 sec interval
c. Select NMI
d. Enable WDT
e. Clear WDT
f. Disable WDT
a. Set RTC to generate WDT timer source “SQW” to generate 0.5 sec.
duty
cycle timer source
MOV
AL, 0A
; Set RTC output signal “SQW” to generate 0.5 sec.
cycling timer
MOV
DX, 070
OUT
DX, AL
MOV
AL, 2F
MOV
DX, 071
OUT
DX, AL
MOV
AL, 0B
; Enable “SQW” signal pin active
MOV
DX, 070
OUT
DX, AL
MOV
AL, 0A
MOV
DX, 071
OUT
DX, AL
