Analog output stops, Status 1 Register gives weird value

[Thorsten_Jens]

Addendum/Clarification: AO_Reset and AO_Personalize alone do not suffice to make the card work again. I call those functions when opening a handle to my device, but after the card went dead once those functions can't change its status.

Reloading the driver does usually solve the problem, though. I am not sure if Windows maybe shuts down the current to the card if there is no driver loaded, thus resetting it more thoroughly.

[Thorsten_Jens]

I am still struggling with the interrupt stopping for no apparent reason. It seems to have something to do with system load -- the higher the load is, the less the chance becomes that the interrupt stops.

In such an event, it can be that my ISR is still called (because it is in the chain with other ISRs), and the AO Overrun bit is set in the control register, while the Interrupt B bit is clear. So the card works, but stopped sending FIFO interrupts.