Al Ciplickas

Simultaneous events on the S12

Discussion created by Al Ciplickas on Jan 29, 2007
Latest reply on Jan 29, 2007 by Al Ciplickas
I've been using the S12 and the UF32 for a few years. A problem that seems to come up has me confused. I have to entertain multiple Input Capture events on both cpu's. It's easy to set up ISR's and set the TIE and other registers to capture the events. Now the most critical event set up is when 2 or more events happen simultaneously. I do this test by using the same 1 KHz (square wave) input to 2 IC pins. In both CPU's, only one ISR fires. On the UF32, the flag is set for the second event, but the ISR is never invoked. In that case, I learned to handle the 'other' flag in the current ISR and process the event. On the S12 (MC9S12DJ256B..-80pin), the 'other' event's flag is Not even set. So although I can handle its event, I don't know to do it. Ignoring it makes chaos. The fix is to make the second event happen on the falling edge. That works for event processing (proving my setup is correct), but not for reality of events.

Has anyone else experienced this kind of behavior. I'm ready to turn in a Service Request to see if FSL has any help.

Thanks.

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