How to use Mechaduino's Rx Tx pins?

[pe...@ascest.com]

Hi - I'm struggling with commanding my Mechaduino via the Rx (D0) and Tx (D1) pins. I have not had any problem obtaining the behavior I'm looking for (drum striking) by coding r values in the main loop. However, when I developed my code further to use the Rx pin to receive serial data from an Arduino I can't get a response from the Mechaduino. I can confirm that command characters are being generated from the Arduino... I feel I'm missing something but can't see what. Help to get on the right track would be very helpful. I see this question has been asked before so I'm sure any help will be of interest to others too. Thanks in advance, Peter

Receiving code on the Mechaduino:

/*

  -------------------------------------------------------------

  Mechaduino 0.1 & 0.2 mFirmware  v0.1.4

  SAM21D18 (Arduino Zero compatible), AS5047 encoder, A4954 driver

  All Mechaduino related materials are released under the

  Creative Commons Attribution Share-Alike 4.0 License

  https://creativecommons.org/licenses/by-sa/4.0/

  Many thanks to all contributors!

  --------------------------------------------------------------

*/  

#include "Utils.h"

#include "Parameters.h"

#include "State.h"

#include "analogFastWrite.h"

int incomingByte;

//////////////////////////////////////

/////////////////SETUP////////////////

//////////////////////////////////////

void setup()        // This code runs once at startup

{                         

   

  setupPins();                      // configure pins

  setupTCInterrupts();              // configure controller interrupt

  SerialUSB.begin(115200);          

  delay(3000);                      // This delay seems to make it easier to establish a connection when the Mechaduino is configured to start in closed loop mode.  

  serialMenu();                     // Prints menu to serial monitor

  setupSPI();                       // Sets up SPI for communicating with encoder

  

  Serial.begin(115200);             // Starts Rx/Tx communication on Mechaduino pins D0 (Rx) and D1 (Tx)

  // Uncomment the below lines as needed for your application.

  // Leave commented for initial calibration and tuning.

  

  // configureStepDir();           // Configures setpoint to be controlled by step/dir interface

  // configureEnablePin();         // Active low, for use wath RAMPS 1.4 or similar

     enableTCInterrupts();         // uncomment this line to start in closed loop 

     mode = 'x';                   // start in position mode

}

  

//////////////////////////////////////

/////////////////LOOP/////////////////

//////////////////////////////////////

void loop()                 // main loop

{

  serialCheck();

  Serial.println ("Loop starting point");

  // see if there's incoming serial data:

  if (Serial.available() > 0) 

  {

    // read the oldest byte in the serial buffer

    incomingByte = Serial.read();

    Serial.println (incomingByte);

    

    // if it's a capital H (ASCII 72), start/continue HITTING the drum:

    if (incomingByte == 'H')

    {

       Serial.println ("H character received");

       r = 10;

       delay (random(100,110));

       r = (random(-15, -10));

       delay (random(1000,950));

    }

    // if it's an S (ASCII 83) STOP hitting the drum/continue waiting at r=10

    if (incomingByte == 'S')

    { 

      Serial.println ("S character received");

      r = 10;

    }

  }

}

Code that generates command characters ('H' and 'S') on the Arduino:

// Determine action code to send to drum based on velocity value received

    if (velocityByte > 0 && velocityByte <= 127 && hMessageSent == false)

    {

      digitalWrite(6, HIGH);

      Serial.println ('H'); // send tx message to Mechaduino to START playing

      hMessageSent = true; // Register that 'H' message was sent. Don't send more

      sMessageSent = false;

    }

    if (velocityByte == 0 && sMessageSent == false)

    {

      digitalWrite(6, LOW);

      Serial.println ('S'); // send tx message to Mechaduino to STOP playing

      sMessageSent = true; // Register that 'S' message was sent. Don't send more

      hMessageSent = false;

    }