ECM-3410/3410L/3410N
ECM-3410/3410L/3410N User’s Manual
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Appendix C: Programming the Watchdog Timer
Introduction
The ECM-3410 onboard watchdog timer is based on an 8-bit counter. The time interval is
from 16 seconds to 127 minutes with a resolution of 30 seconds. As soon as the timer is
out, the system will generate a reset signal.
Configure Register
The ECM-3410 onboard watchdog timer function is integrated in the I/O chip, Winbond
W83977F. If you would like to utilize this function in your program, you have to know how to
program the 83977F configuration register. The W83977F I/O chip decode address is 3F0h.
The index port and data port is 3F1h. The way to program the register is to write the
register number to index port, then read / write data from / to data port.
The following procedures show how to program the W83977F register and use the
watchdog function.
1. Unlock W83977F I/O chip and enter configuration mode.
2. Select Logical Device.
3. Select register number.
4. Read / Write data from / to register.
5. Lock W83977F I/O chip and exit from configuration mode.
