Advantech MIC-3758DIO, Руководство пользователя

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25 Chapter 4
4.3 Power-up States Function
User-configurable power-up states are useful for ensuring that the MIC-
3758DIO powers up in a known state. When the system is powered-up,
all output Darlington arrays of MIC-3758DIO are user-configurable for
output. So you can predefine the outputs. This function ensures the card’s
output state can be defined at any time. Power-up states are programmed
in EEPROM with a driver. In the EEPROM Control Register you can
write the predefined output data to EEPROM. The default value from the
factory is all set to 0. For more details about register operations, please
refer to Appendix C.
4.4 Watchdog Timer Register Operation
This feature is used to set critical outputs to safe states in the event of a
software failure. When the watchdog timer is enabled, MIC-3758DIO has
to receive a watchdog clear software command within the specified inter-
val time. If it doesn’t, this is considered a loss of communication between
the application and MIC-3758DIO, and 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 software.
After the watchdog timer expires, MIC-3758DIO will ignore any writes
until the watchdog timer is disabled. You can set the watchdog timer tim-
eout period through the WDT register to specify the amount of time that
must elapse before the watchdog timer expires. The counter on the watch-
dog timer is configurable up to 2
32
-1 x 100 ns (approximately seven min-
utes) before it expires. For more details about the watchdog timer register
operation, please refer to Appendix C.
4.5 BoardID Switch
MIC-3758DIO has a built-in BoardID DIP switch (SW2), which is used
to define each card’s unique identity. You can determine the BoardID set-
ting in the register as shown in Table 4.2. When there are multiple cards
on the same chassis, the BoardID setting function is useful for identifying
each card’s device number. MIC-3758DIO’s BoardID setting is set to 0 at
the factory. If you need to adjust it to another number, set SW2 by refer-
ring to Table 4.3.