Advantech MIC-3758DIO, User Manual

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MIC-3758DIO User Manual 4
1.2.3 Programmable Power-Up State Function
User-configurable power-up states are useful for ensuring that MIC-
3758DIO powers up in a known state. Power-up states are programmed in
the EEPROM through the driver.
1.2.4 Watchdog Timer Function
The watchdog timer is a software configurable feature used to set critical
outputs to safe states in the event of a software failure. If there is loss of
communication between the application and MIC-3758DIO, if the watch-
dog timer is enabled and MIC-3758DIO does not receive a watchdog
clear software command within the interval time specified for the watch-
dog timer, the outputs go to a user-defined safe state and remain in that
state until the watchdog timer is disabled and new values are written by
the software. After the watchdog timer expires, MIC-3758DIO ignores
any writes until the watchdog timer is disabled. You can set the watchdog
timer timeout period through the WDT register to specify the amount of
time that must elapse before the watchdog timer expires. The counter on
the watchdog timer is configurable up to 2
32
-1 x 100 ns (approximately
seven minutes) before it expires.
1.2.5 Reset Protection
If the system has undergone a hot reset (i.e. system power was not turned
off), MIC-3758DIO can either retain output values of each channel, or
return to its default configuration as power up status, depending on its on-
board jumper setting. This function protects the system from wrong oper-
ations during unexpected system resets.