ADLINK Technology NuPRO-780 Series, Руководство пользователя

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Watchdog Programming
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Watchdog Programming
NuPRO-780 implements a watchdog timer embedded in the 83627HF. It
contains a one-second/minute resolution down counter (in CRF6 of logical
device 8 of 83627HF) and two Watchdog control registers (CRF5 and CRF7
of logical device 8). Once setup a value to WDT, the timer begins to count
down.
Any movement of keyboard, mouse or software re-setup the value will
reload the timer value. The Watchdog output is connected to “reset”. When
the system hangs up without software re-trigger, the system will be reset.
So basically this is a watchdog timer that has a 1 second granularity up to
255 seconds or a 1 minute granularity up to 255 minutes. The keyboard and
mouse will only reset WDT if Bit 7 and 6 of CRF7 is set, that is values
greater than C0h or 192 decimal.
To configure the registers, the following sequence should be followed :
1. Writing 87h to location 2Eh twice to enter into the extended function
mode.
2. Configure the registers to set up WDT.
3. Writing 0AAh to location 2Eh to exit the extended function mode.
The example shown below will reset the system after 15 seconds. Both
keyboard and mouse interrupts will reload WDT from CRF6.