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Re: PortA Interrupt Handling

On Fri, 9 Nov 2001, Greg Cannon wrote:
> I have written driver code that successfully gets an interrupt on PortA.
> However, since PortA is level, I will continue to get interrupts until the
> external pin goes low.

Apart from the HW suggestion with the flip-flop, I've handled this case
like you do - the interrupt disables the trigged pin irq before enabling
interrupts again. Your method with delaying the enabling should work
fine. If you post the code I can check if there is anything wrong with it.

I actually believed the 100LX had the possibility to edge-trig or at least
choose polarity on the port PA irq's, but I could not find it in the docs
so maybe it hasn't. If so, yes, it'll probably go in any future parts
since it's a common suggestion (or at least we can hope)

Choosing level polarity would be enough since you can then change polarity
in the interrupt routine instead of disabling it.