User’s Manual
138 ECM-3610/3610L User’s Manual
Appendix C: Programming the Watchdog Timer
Introduction
The ECM-3610 onboard watchdog timer uses an 8-bit counter, so it has 256 resolution
and the time range is from 1 second to 255 seconds with a resolution of 1 second. When
the timer is setting and time-out occurs, it will trigger the hardware reset signal or interrupt
signal (only IRQ 10 and IRQ 11), when you setting the time-out trigger event is hardware
reset, a system reset will happen.
Programming Watchdog Timer
About how to program the ECM-3610 onboard watchdog timer function and the procedure
of using watchdog function are describe as follow.
Program watchdog procedure:
1. Set watchdog timer time-out trigger mode.
Hardware Reset: write value(00h) to port 444h
IRQ 10 : write value(04h) to port 444h
IRQ 11 : write value(03h) to port 444h
ex: outportb(0x444, 0x00);
2. write time-out value(00h ~ FFh) to timer port (443h).
00h : Time-out Disable
01h : Time-out occurs after 1 second
02h : Time-out occurs after 2 seconds
03h : Time-out occurs after 3 seconds
04h : Time-out occurs after 4 seconds
05h : Time-out occurs after 5 seconds
.
.
FFh : Time-out occurs after 255 seconds
Followings show two examples of programming the watchdog timer with 15 seconds time
interval in both Micro-assembly and C language.
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