CTI 2500-VP15, Руководство пользователя

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Appendix
Appendix A: Watchdog Timer (WDT) Setting
WDT is widely applied to industry computers to monitor activities of CPU. The
programmed application triggers WDT with adequate timer setting depending
on its requirement. Before WDT counts down to zero, the functional system
will reset the counter. In case the WDT counter is not reset by an abnormal
system, it will counts down to zero and then reset the system automatically.
This computer supports watchdog timer up to 255 levels for software
programming. Below please take the source code written in assembly & C for
a WDT application example.
Source Code in Assembly Language
============================
mov
mov
mov
out
out
ax,2eh
dx,ax
ax,87h
dx,al
dx,al
; initial IO port twice
mov
mov
mov
out
inc
mov
out ax,2eh
dx,ax
al,07h
dx,al
dx
al,08h
dx,al
; point to logical device selector
; select logical device 8
mov
mov
mov
out
inc
mov
out ax,2eh
dx,ax
al,30h
dx,al
dx
al,01h
dx,al
; select CR30
; update CR30 to 01h, WDTO enable
mov
mov
mov
out ax,2eh
dx,ax
al,0f5h
dx,al
; select CRF5 to set timer unit
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