[sdiy] bizarre pic-midi issues

[johnspeth at yahoo.com]

Byron's response was a good recital of the usual suspects when serial communication goes wrong.  MIDI goes a step further than non-optically coupled comm links with the optoisolator.  It sounds like your link is just marginal maybe because of excess resistance or slow optocoupler or even a bad ground (which can make it look sort of AC coupled, sorta).  That's where I'd start looking first with a scope and analysis.

JJS