SERout for MIDI problems

Rickster

I am trying to make a bank changer in MIDI and was reading the N&V issue 94. after unsucsessfuly trying this project with my keybord i'm at a loss as to why it wont work and i need som help trobleshooting this. It should be fairly easy.

BS2p24 chip
I connected io pin 15 to 500 ohm's and an led to ground to test the output, it comes on.

the original program was writen for a difrent chip but my baud rate shoud be 60 to get 31,500 baud, orginal was 20 in the program.
I hooked pin 5 of the midi cable to pin 15 and pin 4 to +5vdc and pin 2 to ground. I have quadruple checked this. I have also reversed pins 4 and 5 as I read somewher that it was wrong. nether orientation works.
My program looks like this to test it -

'·· {$STAMP BS2p}
'·· {$PBASIC 2.5}

MidiOut········ PIN···· 15····················· ' midi serial output
MidiBaud······· CON···· $8000 +·60············· ' 31.25 kBaud -- open

Main:
· DO
····· SEROUT MidiOut, MidiBaud, [noparse][[/noparse]$90, $3C, $7F]
······PAUSE 500
· LOOP
· END
This should send a signal to play the note every half second, but I get nothing. What am I missing?

Chris Savage

Rickster,

Do you have the resistors listed? Without them a wiring mistake could cause damage. You may want to verify the data is getting to the other end of the cable. This would be easier if you have a meter or scope.

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Chris Savage
Parallax Tech Support

Rickster

Yes I had 220 ohm resisters on pin 4 and 5.

I found the problem earlyer today. It would seem that my cable is bad at some point with an intermitint open connection when bent just a bit neer the plug, its molded so i had to replace it with the other half i choped off earlyer. sad part is its only 3" long [noparse]:)[/noparse]

I can get my chanel to change now with -
SEROUT MidiOut, MidiBaud, [noparse][[/noparse]$C0, $11]
works great, need to find the command for the foot controller and find a good foot pedal i can use with a pot in it for the foot control of the wha in the preamp yet. Lots of the documentation on midi is fairly·easy but not very concise.

I think the foot controler· [noparse][[/noparse]$B0, $24, $00 to ·$7F] will work to control it but the midi documentation·has $04, $24, $0B or $2B for the foot control and I cant seem to find rocktron midi tables. I'll have to run through them to see.

Post Edited (Rickster) : 1/12/2007 12:51:23 AM GMT

Rickster

This code changes to patch 37 then moves into a few loops to change the center Frequency of the wah through midi. I can get the patch to change but the wha isn't working yet. My question is SEROUT MidiOut, MidiBaud, [noparse][[/noparse]$B0, $04, HEX fCenter] correct in stating HEX fCenter or do I need to add HEX #fCenter to output it correctly. The Debug showes me what i'm looking for 00-7F in hex.
I could be wrong in the mapping for the foot controler also, its simple just not documented yet.

'   {$STAMP BS2p}
'   {$PBASIC 2.5}
MidiOut         PIN     15                      ' midi serial output
MidiBaud        CON     $8000 + 60              ' 31.25 kBaud -- open
fCenter         VAR     Byte
Main:
    SEROUT MidiOut, MidiBaud, [noparse][[/noparse]$C0, $24]
      PAUSE 100
      fCenter = $00
      DEBUG HEX fCenter
DO
PAUSE 100
      DO
        SEROUT MidiOut, MidiBaud, [noparse][[/noparse]$B0, $04, HEX fCenter]
        fCenter = fCenter + $01
        DEBUG HEX fCenter, CR
        PAUSE 5
      LOOP  UNTIL fCenter = $7F
PAUSE 100
      DO
        SEROUT MidiOut, MidiBaud, [noparse][[/noparse]$B0, $04, HEX fCenter]
        fCenter = fCenter - $01
        DEBUG HEX fCenter, CR
        PAUSE 5
      LOOP UNTIL fCenter = $01
LOOP
END