SoftwareSerialMIDI_Interface only RX on pin 0

[ELENICK97]

Hi everybody.

I have a question regarding the usage of SoftwareSerialMIDI_Interface.
I have a project using an Arduino Leonardo.
Due to a pin shortage and a poorly designed PCB, I ended up needing to use pin 1 as a GPIO for a 4051 multiplexer, while I need pin 0 to receive MIDI messages from a DIN midi connector.
So, I thought to use SoftwareSerialMIDI_Interface in order to do this, because hardware serial, as far as I understood, needs to occupy both 0 and 1 pins. Following is my code:

`#include <Control_Surface.h>
#include <SoftwareSerial.h>
#include "C:\Users\nicol\Documents\Arduino\libraries\Control_Surface\src\MIDI_Interfaces\SoftwareSerialMIDI_Interface.hpp"

SoftwareSerial mySer(0, -1); //I set the tx pin to -1 in order not to use any real pin
SoftwareSerialMIDI_Interface midi_ser = {mySer, MIDI_BAUD};
USBMIDI_Interface midi_usb;
MIDI_Pipe pipe_ctrl_USB, pipe_DIN_USB;

CD74HC4051 mux_pot1 { //U5
A0,
{13, 12, 11}
};

CD74HC4051 mux_pot2 { //U2
A1,
{6, 5, 4}
};

CD74HC4051 mux_SW1 { //U3
7,
{3, 2, 1}
};

CD74HC4051 mux_SW2 { //U4
A5,
{8, 9, 10}
};

CCPotentiometer potentiometers[]{
//FADERS
{mux_pot2.pin(4),{62, Channel_1}}, //RV1
{mux_pot2.pin(5),{63, Channel_1}}, //RV2
{mux_pot2.pin(6),{64, Channel_1}}, //RV3
{mux_pot2.pin(7),{65, Channel_1}}, //RV4
{mux_pot1.pin(3),{53, Channel_1}}, //RV5
{mux_pot1.pin(7),{57, Channel_1}}, //RV6
{mux_pot1.pin(5),{55, Channel_1}}, //RV7
{mux_pot1.pin(6),{56, Channel_1}}, //RV8
{mux_pot1.pin(4),{54, Channel_1}}, //RV9
//ROTARY POTS
{mux_pot2.pin(0),{58, Channel_1}}, //RV10
{mux_pot2.pin(1),{59, Channel_1}}, //RV11
{mux_pot2.pin(2),{60, Channel_1}}, //RV12
{mux_pot2.pin(3),{61, Channel_1}}, //RV13
{mux_pot1.pin(2),{52, Channel_1}}, //RV14
{mux_pot1.pin(1),{51, Channel_1}}, //RV15
{mux_pot1.pin(0),{50, Channel_1}}, //RV16
{A2, {66, Channel_1}}, //RV17
{A3, {1, Channel_1}}, //potH joystick
};

PBPotentiometer PitchBend2 { //potV joystick
A4, // Analog pin connected to potentiometer
Channel_1, // MIDI Channel 1
};

CCButton buttons[]{
{mux_SW1.pin(4), {73, Channel_1}}, //S4
{mux_SW1.pin(2), {72, Channel_1}}, //S3
{mux_SW1.pin(6), {71, Channel_1}}, //S2
{mux_SW1.pin(1), {70, Channel_1}}, //S1

{mux_SW2.pin(1), {74, Channel_1}}, //S5
{mux_SW2.pin(2), {75, Channel_1}}, //S6
{mux_SW2.pin(4), {76, Channel_1}}, //S7
{mux_SW2.pin(6), {77, Channel_1}}, //S8
};

CCButton pushbuttons[]{
{mux_SW1.pin(0), {80, Channel_1}}, //SW1
{mux_SW1.pin(3), {81, Channel_1}}, //SW2
{mux_SW1.pin(5), {82, Channel_1}}, //SW3
{mux_SW1.pin(7), {83, Channel_1}}, //SW4

{mux_SW2.pin(0), {84, Channel_1}}, //SW5
{mux_SW2.pin(3), {85, Channel_1}}, //SW6
{mux_SW2.pin(5), {86, Channel_1}}, //SW7
{mux_SW2.pin(7), {87, Channel_1}}, //SW8
};

void setup() {

midi_usb.setAsDefault();
Control_Surface >> pipe_ctrl_USB >> midi_usb; //Control surface sends messages to USB interface
midi_ser >> pipe_DIN_USB >> midi_usb; //MIDI coming from the DIN socket sends messages to USB interface

for (int i=9; i<17; i++){ // Faders are inverted for Hammond drawbars
potentiometers[i].invert();
}

Control_Surface.begin();
}

void loop() {
Control_Surface.loop();
}
`

The control surface part works as expected: all pots and switches send MIDI messages to the USB interface, but when I play something with my keyboard attached to the MIDI DIN plug, nothing is sent to the USB interface (and I also assume nothing is received by the Software serial (?)).
Could anyone tell me what I am doing wrong and if my problem can be solved?

Please tell me if you need any additional info.
Thank you so much in advance.

[tttapa]

I don't know if this is the only issue, but from the SoftwareSerial docs: https://docs.arduino.cc/learn/built-in-libraries/software-serial/

Not all pins on the Leonardo and Micro boards support change interrupts, so only the following can be used for RX: 8, 9, 10, 11, 14 (MISO), 15 (SCK), 16 (MOSI).

[ELENICK97]

Oh, thank you. Reading this article I wrongly assumed that pin 0 had interrupts https://docs.arduino.cc/language-reference/en/functions/external-interrupts/attachInterrupt/
It was easier than I thought. Now the application is working fine
Thank you again.