I'm modifying an open source PIC program in assembly language that takes user input for parameter control. The input parser is primitive and vulnerable to crashes from input overload. I did a few minutes of searches for lexical analysis but couldn't find anything related to this. Are there any lexical analyzers out there that target PIC assembly, or do I need to do this with lex/flex and create a C module? I don't have any experience with C in a PIC environment, and I'm not so sure this would be a good fit due to the way the variables are declared. I could be wrong.

Most likely the crash is due to some simple off-by-one or out-of-bounds error. If you want to post the offending code there are likely some people here who can help. flex might be overkill for PIC. Last I checked space was kind of tight.

I've been examining the code some more, and I think I found the problem. In the interrupt section, if the end of buffer is reached, he stops putting new chars in the buffer. In the input consumption routine if the end of line character is never reached no action is taken. I'm not sure what causes the freeze of the heartbeat LED, but I think the big culprit is solved.

I've been looking at this code for a long time, and I've been avoiding this particular problem because I wasn't able to reliably reproduce it until I got lucky yesterday. It will be good to get rid of it. Still, I think the idea of a lex that produces code for PICs is a useful one.