NEXCOM NSA 3130 - Manual (Page 88)

Copyright © 2012 NEXCOM International Co., Ltd. All Rights Reserved. 75 NSA 3130 User Manual
Appendix A: Watchdog Timer
Watchdog Timer Setting
NSA 3130 features a watchdog timer that resets the CPU or
generates an interrupt if the processor stops operating for
any reason. This feature ensures 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.