Phillip wrote:
> I was not disabling interrupts during my ISR.
> Now that interrupts are off and I'm not calling my c routine recursively
> things are much better behaved.

This again makes no sense.  The hardware disables interrupts when the ISR is
entered.  The ISR re-enables interrupts by using the RETFIE instruction when
it returns to the foreground code.  You should not otherwise be messing with
interrupt enable/disable in the ISR.

> I'm not sure why calling the getcUSART1 from my ISR is such a bad idea.

Using a high level language, particularly in the ISR, is a bad idea
especially when you're not clear what is really going on.  Many people here,
including me, always say to do your first few PIC projects in assembler
until you have a solid understanding of the machine and the instruction set.
Only then should you be allowed to use a high level language.  Otherwise you
run into exactly the kind of situation you did, where strange things are
happening and you can't figure out what because things are going on under
the hood that you don't understand.

Let this be a lesson to you and everyone else from the instant gratification
crowd that thinks they can get away with not understanding the low levels
and jump right into using a HLL on a PIC.

Other reasons for avoiding HLL in the ISR is that the compiler has to
save/restore a lot more state than really neccessary (take a look at the
generated instructions some time), if any code is speed-critical it's
probably the ISR, and calling subroutines from the ISR uses up stack
locations not available to any other code.


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