6520 PIA behavior

Bry · Post by **Bry** » Wed Jul 16, 2008 7:04 pm

Question...

If I'm using CA1 or CB1 as an input, and I flip the polarity bit (bit 1 of CRA, CRB) without any change on the actual CA1 or CB1 line, will anything happen?

What I'm kind of wondering is if the polarity bit inverts the incoming signal generating false interrupts as the bit is changed. This would actually be nice for my application, since I'd like to be able continually monitor these signals and not just latch transitions (make extra inputs out of them).

Thanks!

-Bry

Bry · Post by **Bry** » Thu Jul 17, 2008 9:05 pm

Never mind. It doesn't work that way.

Can someone verify something else? According to the datasheet I'm looking at, you must read port A to clear the interrupt. However, writing to it seems to work too.