Example Program - Advantech PCA-6742 User Manual

Table B.1: Watchdog Timer Registers
Address of
register (2E)
87 (hex)
07 (hex)
30 (hex)
F5 (hex)
F6 (hex)
F7 (hex)
AA (hex)
B.1.2

Example Program

1. Enable watchdog timer and set 10 sec. as timeout interval
;-----------------------------------------------------------
Mov dx,2eh
Mov al,87h
Out dx,al
Out dx,al
;-----------------------------------------------------------
Mov al,07h
Out dx,al
Inc dx
Mov al,08h
Out dx,al
;-----------------------------------------------------------
Dec dx
Mov al,30h
Out dx,al
Inc dx
Mov al,01h
Out dx,al
;-----------------------------------------------------------
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Attribute
Value (2F) and Description
Read/Write
Write this address to I/O address port 2E (hex) twice to
-----
unlock the W83627HG
write Write 08 (hex) to select register of watchdog timer.
Write 01 (hex) to enable the function of the watchdog timer.
write
Disabled is set as default.
Set seconds or minutes as units for the timer. Write 0 to bit 3:
write set second as counting unit. [default]. Write 1 to bit 3: set
minutes as counting unit
0: stop timer [default]
01~FF (hex): The amount of the count, in seconds or min-
utes, depends on the value set in register F5 (hex). This
write number decides how long the watchdog timer waits for
strobe before generating an interrupt or reset signal. Writing
a new value to this register can reset the timer to count with
the new value.
Bit 6: Write 1 to enable keyboard to reset the timer, 0 to dis-
able.[default]
Bit 5: Write 1 to generate a timeout signal immediately and
read/write
automatically return to 0. [default=0]
Bit 4: Read status of watchdog timer, 1 means timer is "time-
out".
Write this address to I/O port 2E (hex) to lock the watchdog
-----
timer 2.
; Unlock W83627HG
; Select registers of watchdog timer
; Enable the function of watchdog timer
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