Copyright © 2011 NEXCOM International Co., Ltd. All Rights Reserved.
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NSA 5130 User Manual
Appendix A: Watchdog Timer
Appendix A: Watchdog Timer
Watchdog Timer Setting
NSA 5130 features a watchdog timer that resets the CPU or generates an
interrupt if the processor stops operating for any reason. This feature en-
sures system reliability in industrial standalone or unmanned environments.
Set pin 89 as a WDTO output. Write ‘0’ to CR2B[4].
1. Select timer type (Sec/Min). LD8 CRF5[3] (0: sec, 1: min)
2. Clear timeout status. Write ‘0’ to LD8 CRF7[4].
3. Set the timeout value. Meanwhile the timer will start to count down.
4. Write a value to LD8 CRF6. When a timeout occurs, pin 89 will become
active (high level).
5. CRF6 must be 0x0. Write another 0x00 to CRF6 (timeout disable) even
though it is already 0x00. Clear the timeout status. Write ‘0’ to LD8
CRF7[4]. pin 89 will fall at the same time.
CRFC6 (Default 0x00)
Watchdog Timer Time-out Value
Writing a non-zero value to this register causes the counter to load the
value to Watchdog Counter and start counting down. If Bit 7 and Bit 6 are
set, any Mouse Interrupt or Keyboard Interrupt event will also cause the
reload of previously-loaded non-zero value to Watchdog Counter and start
counting down. Reading this register returns current value in Watchdog
Counter.
Dog Timer Time-out Value
BIT
Definition
7-0
0x00 time-out disabled
0x01 time-out occurs after 1sec./min.
0x02 time-out occurs after 2 sec./min.
0x03 time-out occurs after 3 sec./min.
0xFF time-out occurs after 255 sec./min.
