12. Watchdog Timer
ÛZIATECH
72
jnz
multiple_on
and
al,not 10h
multiple_o
n:
endm
;-------------------------------------------------------------
; strobe_wd strobes and re-arms the watchdog timer.
; The state of Bit 1 must be maintained (write the same value
as was read).
; Bits 3 & 4 must be handled as shown in the input_e5 macro
;-------------------------------------------------------------
strobe_wd
pushf
cli
input_
e5
and
al,not 1
out
0e5h,al
or
al,1
out
0e5h,al
popf
ret
ADDITIONAL INFORMATION
The chip used for the watchdog timer is a DS 1238A. Refer to the Dallas Semiconductor
DS1705/DS1706 3.3 and 5.0 V MicroMonitor™
data sheet for more information on the
watchdog timer and the associated operating modes. The data sheet is available online
at
http://www.dalsemi.com/DocControl
The data sheet is in Adobe Acrobat format (PDF). If you do not have the Acrobat
Reader, it is available on the Adobe Home Page at