Author Topic: False triggering of MIDI program change  (Read 2494 times)


False triggering of MIDI program change
« on: September 05, 2006, 02:07:53 PM »
This is a little disconcerting.  Has anyone else run into this?  If so, how did you handle it?  Will my proposed solution (below) work?  I hope so.

OK, I'm close enough to taste victory on my bass pedal unit, but I have another dragon to slay (or at least render harmless).  I've noticed when my octave change logic changes "up" to the highest octave or "rolls over" from the lowest octave to the highest, a MIDI program change message appears to be generated and the keyboard I'm using as a tester does a voice change.  Now, this is a pretty old keyboard and it might just not be "playing nice" with my controller.  I'm betting I wouldn't have this same problem with a NanoBass.  Then again, I could have found an issue that's a project-destroyer and I'd better beat it now.  What's weird is that I have a "harmony mode" selector that counts four harmony modes and then resets.  This doesn't cause any difficulties.  However, I think this is actually a clue because I haven't implemented the logic to display the harmony mode yet since I only have one 4511 connected to my PIC.

The possible solution I came up with was to put the "MIDI send" pin (RA4) on the '628 into INPUT mode except when I need to transmit MIDI.  I'm wondering if something is going on because of read/update/write (or whatever that phenomenon is called).

Help!  Anyone know where St. George is, or at least his sword?


Feeling like the Little Red Hen here, guys!
« Reply #1 on: September 08, 2006, 08:21:17 AM »
Geez Louise!  Forty-nine views and no responses?  ???  What a bummer!

Well, like the Little Red Hen said, "I'll do it myself!"  Putting the MIDI send pin into INPUT mode helped, but weird things were still happening.  It turns out that I had driven the battery (I've been testing with a 9V battery as my power supply -- that changes this weekend!) into low-voltage death.  Tried a new battery.  All operational modes appear to be stable.  Next step is to add the circuitry and programming for the other LED digit.


Re: False triggering of MIDI program change
« Reply #2 on: September 14, 2006, 02:29:45 PM »
D'OH!!!!    :icon_evil:

It would help if I had used the right bloody instruction!!!!!!!!!!!!!!!!