Wouter van Ooijen wrote:

>> [ICD2 debugging]
>> FAR more powerful than serial debugging.  FAR FAR FAR more powerful.
> 
> In some situation yes, but I have an ICD2 at my desk yet I seldom use
> it. I often prefer serial logging, because it does not disturb the
> timing of the application much (at least not when you limit your
> debugging info). And you can do serial logging with any pin you want, a
> software UART is not that difficult.

Exactly my approach, too. I pretty much never have to step through live
code. If there's something that needs stepping through, it's in most cases
a small, limited piece of code and a simulator (or a brain :) is way more
convenient. (The ICD2 steps really slowly.) My other debugging challenges
usually involve the whole application and its realtime behavior together
with the process -- and stepping through any of this wouldn't do me much
good. Neither does the possibility to set any SFRs seem to be very
important to me; the phase to figure out how to configure a new peripheral
seems to be quite short. 

For debugging the realtime application behavior, serial logging is a real
godsend; especially if it's already planned into the design. I use debug
macros that either insert print statements that can be controlled by bits
on a file-by-file basis (each file has eight categories of print statements
available) or nothing (for release builds). If during testing I have a
certain "question" for a certain piece of code, I just enable one or more
of these bits. Of course, sometimes I have to add extra print macros for
that (because I didn't anticipate the "question" when writing the code) and
re-program the chip, but then to disable these again is just a matter of
setting the bit to 0 -- no temporary inserting and removing of debug code
necessary. The statements remain available if needed later (or when
re-using that piece of code in a different application).

I do have an ICD2 here, but for these reasons I pretty much exclusively use
it as an ICSP programmer. 

BTW, there's nothing that says that you can't do a half-duplex serial
connection through one pin. What one usually sends back to the processor in
such a scenario are simple, slow commands with a few characters (for
example to set or clear such a print control bit). 

Gerhard

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