Multiplexing for Midi Controller

[Gripporillat]

Hi everybody!

I'm trying to figure out how multiplexing works. If this is my circuit:



and this is my code:

#include "MIDIcontroller.h"
byte MIDIchannel = 1;
const int Mpx1 = A0; //Multiplexer 1 on Pin A0
const int Mpx2 = 3; //Multiplexer 2 on Pin 3

MIDIpot PotMpx1Chan0(Mpx1, 0);     //Potentiometer on Multiplexer 1, Channel 0 for ControlChange #0
MIDIpot PotMpx1Chan1(Mpx1, 1);     //Potentiometer on Multiplexer 1, Channel 1 for ControlChange #1
MIDIpot PotMpx1Chan2(Mpx1, 2);     //Potentiometer on Multiplexer 1, Channel 2 for ControlChange #2
MIDIpot PotMpx1Chan3(Mpx1, 3);     //Potentiometer on Multiplexer 1, Channel 3 for ControlChange #3
MIDIpot PotMpx1Chan4(Mpx1, 4);     //Potentiometer on Multiplexer 1, Channel 4 for ControlChange #4
MIDIpot PotMpx1Chan5(Mpx1, 5);     //Potentiometer on Multiplexer 1, Channel 5 for ControlChange #5
MIDIpot PotMpx1Chan6(Mpx1, 6);     //Potentiometer on Multiplexer 1, Channel 6 for ControlChange #6
MIDIpot PotMpx1Chan7(Mpx1, 7);     //Potentiometer on Multiplexer 1, Channel 7 for ControlChange #7

MIDIbutton ButtonMpx2Chan0(Mpx2, 8, MOMENTARY);       // Button on Multiplexer 2, Channel 0 for ControlChange #8
MIDIbutton ButtonMpx2Chan1(Mpx2, 9, MOMENTARY);       // Button on Multiplexer 2, Channel 1 for ControlChange #9
MIDIbutton ButtonMpx2Chan2(Mpx2, 10, MOMENTARY);       // Button on Multiplexer 2, Channel 2 for ControlChange #10
MIDIbutton ButtonMpx2Chan3(Mpx2, 11, MOMENTARY);       // Button on Multiplexer 2, Channel 3 for ControlChange #11
MIDIbutton ButtonMpx2Chan4(Mpx2, 12, MOMENTARY);       // Button on Multiplexer 2, Channel 4 for ControlChange #12
MIDIbutton ButtonMpx2Chan5(Mpx2, 13, MOMENTARY);       // Button on Multiplexer 2, Channel 5 for ControlChange #13
MIDIbutton ButtonMpx2Chan6(Mpx2, 14, MOMENTARY);       // Button on Multiplexer 2, Channel 6 for ControlChange #14
MIDIbutton ButtonMpx2Chan7(Mpx2, 15, MOMENTARY);       // Button on Multiplexer 2, Channel 7 for ControlChange #15


void setup(){
}
void loop(){

    // select multiplexer channel 0
  digitalWrite(1, LOW);
  digitalWrite(2, LOW);
  digitalWrite(3, LOW);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 0
  PotMpx1Chan0.send();
  ButtonMpx2Chan0.send();

    // select multiplexer channel 1
  digitalWrite(1, LOW);
  digitalWrite(2, LOW);
  digitalWrite(3, HIGH);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 1
  PotMpx1Chan1.send();
  ButtonMpx2Chan1.send();

    // select multiplexer channel 2
  digitalWrite(1, LOW);
  digitalWrite(2, HIGH);
  digitalWrite(3, LOW);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 2
  PotMpx1Chan2.send();
  ButtonMpx2Chan2.send();

    // select multiplexer channel 3
  digitalWrite(1, LOW);
  digitalWrite(2, HIGH);
  digitalWrite(3, HIGH);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 3
  PotMpx1Chan3.send();
  ButtonMpx2Chan3.send();

    // select multiplexer channel 4
  digitalWrite(1, HIGH);
  digitalWrite(2, LOW);
  digitalWrite(3, LOW);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 4
  PotMpx1Chan4.send();
  ButtonMpx2Chan4.send();

    // select multiplexer channel 5
  digitalWrite(1, HIGH);
  digitalWrite(2, LOW);
  digitalWrite(3, HIGH);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 5
  PotMpx1Chan5.send();
  ButtonMpx2Chan5.send();

    // select multiplexer channel 6 
  digitalWrite(1, HIGH);
  digitalWrite(2, HIGH);
  digitalWrite(3, LOW);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 6
  PotMpx1Chan6.send();
  ButtonMpx2Chan6.send();

    // select multiplexer channel 7
  digitalWrite(1, HIGH);
  digitalWrite(2, HIGH);
  digitalWrite(3, HIGH);
  
  // allow 50 us for signals to stablize
  delayMicroseconds(50);

  // check and send Values for all multiplexers channel 7
  PotMpx1Chan7.send();
  ButtonMpx2Chan7.send();

  
}

Is it gonna work?

I don't have those multiplexers available yet so I cant just try it.
Thx in advance!
Robert

 

[Gerrit]

For larger setups this seems the way to go: https://forum.pjrc.com/threads/52552-MIDI-DJ-Controller-using-Teensy-3-6-am-I-doing-this-right
IMHO it's a good example of structured code. In stead of trying to come up with your own approach you'd probably be better off studying this code and adapt it to your specific requirements.