Hi, Michael Kelly writes: > At 06:24 AM 6/30/2005, Lothar Wassmann wrote: > >Hi, > > > >Michael Kelly writes: > > > Bill, > > > > > > One issue with the PXA255 edge triggering is that you need > > > to be sure you poll the state of the interrupt line before you > > > re-enable the GPIO interrupt. That way if the device is asking > > > for more servicing, you won't miss it since there will be no > > > edge to detect. > > > > >No. If you mask all interrupts (in the ISP116x chip) upon entering the > >interrupt handler (which will deassert the INT output) and restore the > >interrupt mask register upon exit, you won't miss any interrupts, > >since the interrupt line will be reasserted when another interrupt > >condition exists when interrupts are reenabled. > > > >The ISP116x interrupt handler does it this way. > > > > > >Lothar Wassmann > > Does this handle the fact that the interrupt in the PXA255 > is only recognized when there is a transition (ie edge)? > Yes. Clearing the interrupt mask ensures that the INT GPIO is deasserted. As long as there are any unacknowledged interrupt conditions in the chip the INT GPIO will be reasserted when the interrupt mask is restored upon exiting the handler.
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