Don't be too quick to denigrate IOC!  I'm using IOC on a running
processor and I'm happy as a clam!!

Yes, you do have to be careful - don't poll the port, define the entire
port as inputs, let your interrupt do the reads, etc., but in some
instances, it can be a near ideal answer to an otherwise sticky program.
 You can let your mainline code do all your heavy background routines
and never miss an input change.

In my case, I'm using IOC to handle two 2-bit optical encoder inputs and
three pushbuttons.  Saves me from having to poll those devices at a high
enough rate to ensure no data loss, which would seriously impact the
useful work I need to do in the background.  My input from the encoders
comes in bursts that, when they occur, demand a lot of processor
activity, essentially suspending background activity during that time.
 To do this application in a polling environment would require a lot
more horsepower than I'm presently using (I'm using 16F628s - maxed out
on memory and RAM usage, but sufficient for the job!).

To each their own, I guess!
Dennis

Bob Blick wrote:

>>On Friday, Jun 11, 2004, at 14:28 US/Pacific, Bob Blick wrote:
>>
>>
>>>Interrupt-on-change should be renamed "wake-up-on-change" because it's
>>>useless on a running processor.
>>>
>>>
>>>
>>Oh.  Rats!  I suppose it would be OK if you have the entire port set to
>>be inputs, as in a keyboard scanner?
>>
>>
>
>Yes, but you also don't want to poll the port, so if you use IOC you do
>all reads in the interrupt service routine.
>
>Cheers,
>
>Bob
>
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