I was doing some debugging of USART code under
ICD2 and ran across an anomaly I thought you may be
interested in.  Let's say you have a breakpoint that
hits after RCIF is set but before the code that
checks for RCIF=1 executes.  Because the ICD2 reads
all the registers to display at the breakpoint -
including RCREG - RCIF will be cleared under the
covers.  If you resume execution, your code that
checks RCIF=1 and then reads RCREG will be skipped
and the next character will not be received!

   At the breakpoint, if you look at register PIR1
you can see that RCIF is set.  However, if you single
step after the breakpoint you will see that
RCIF "mysteriously" gets cleared.  This is because
the registers are re-read by ICD2 and now RCIF is
really clear.

  This makes sense if you think about it, but I
needed to contact Microchip support to set me
straight.  They said if you want to avoid this
problem, you have to ensure your breakpoint hits
after the code that reads RCIF runs.

  By the way, they said that SSPBUF is treated
similarly, and that ICE 2000 would behave this way as
well (they didn't mention ICD "1", but I would
imagine the same applies).

Rick


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