Boser HS-6300 Manual page 19

Refresh cycle to WDT before its period setting comes ending of every 1,
2, 10, 20, 110 or 220 seconds. If the Refresh cycle does not active before
WDT period cycle, the on board WDT architecture will issue a Reset or
NMI cycle to the system.
The Watch-Dog Timer is controlled by two I/O ports.
443H I/O Read
443H I/O Read
043H I/O Read
The following sample programs showing how to Enable, Disable and
Refresh the Watch-Dog Timer：
WDT_EN_RF EQU
WDT_DIS EQU
WT_Enable PUSH
PUSH
MOV
IN
POP
POP
RET
WT_Refresh PUSH
PUSH
MOV
IN
POP
POP
RET
WT_DISABLE PUSH
PUSH
MOV
IN
POP
POP
RET
The Enable Cycle
The Refresh Cycle
The Disable Cycle
0433H
0043H
AX ; keep AX DX
DX
DX,WDT_EN_RF ; enable the watch-dog timer
AL,DX
DX ; get back AX, DX
AX
AX ; keep AX, DX
DX
DX,WDT_ET_RF ; refresh the watch-dog timer
AL,DX
DX ; get back AX, DX
AX
AX
DX
DX,WDT_DIS ; disable the watch-dog timer
AL,DX
DX ; get back AX, DX
AX
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