LIN-BUS, MCP2004, Serial write does not work 2

Projects General Guidance
1

Hello, I have been trying to send messages in LIN-BUS, and I used a code made by someone from this forum years ago (system), but it doesn´t work.

This is the code:

#include <SoftwareSerial.h>

//SoftwareSerial IBusSerial(10, 11); // RX, TX for IBus

// Pins we use for MCP2004
const int faultPin = 6;
const int cspin = 7;
const int ledpin = 13;
const int spin1 = 2;
const int spin2 = 3;
const int spin3 = 4;
const int spin4 = 5;


boolean read_byte = false;
boolean led = false;
boolean s1 = false;
boolean s2 = false;
boolean s3 = false;
boolean s4 = false;

byte readbuffer[64];
int i;
int buffer_index = 0;
int buffer_max = 64;
int cksum;
long lastrx;
long lasttx;

void setup() {
  // initialize buffer array to 0's
  memset(readbuffer, 0, sizeof(readbuffer));

  // Open serial communications to host (PC) and wait for port to open:
  Serial.begin(9600, SERIAL_8E1);
  //  Serial.println("IBus Debugging begins");

  // set the data rate for the SoftwareSerial port
  //IBusSerial.begin(9600);

  // Set high to enable TX on MCP2004
  pinMode(cspin, OUTPUT);
  digitalWrite(cspin, HIGH);

  // Set high to enable something ont he MCP2004
  pinMode(faultPin, OUTPUT);
  digitalWrite(faultPin, HIGH);

  lastrx = millis();
  lasttx = millis();
}

void loop() {
  delayMicroseconds(1000);

  lasttx = millis();


  if ((millis() - lastrx) > 15) {
    memset(readbuffer, 0, sizeof(readbuffer));
    buffer_index = 0;
    read_byte = false;
    buffer_max = 64;
    lastrx = millis();
    return;
  }


  if (Serial.available()) {


    readbuffer[buffer_index] = Serial.read();
    read_byte = true;
  }

  if (read_byte) {
    if (buffer_index == 1) {
      buffer_max = readbuffer[buffer_index] + 2;
      cksum = readbuffer[0] ^ readbuffer[1];
    } else if ((buffer_index > 1 ) && (buffer_index < buffer_max)) {
      cksum = cksum ^ readbuffer[buffer_index];
    }
  }
  //0x50 <-- Multi function wheel
  //0x46 <-- Center display
  //0xC0 <-- Multi info display
  //0xE7 <-- Front display <-- 20:59
  //0x3B <-- Navigation display, visas i navi, radiokanal namn
  // Reset buffer_index when it is buffer_max - 1.
  if (buffer_index == (buffer_max - 1)) {
    if (cksum == 0) {
      if (s2) {
        digitalWrite(spin2, HIGH);
      }
      else {
        digitalWrite(spin2, LOW);
      }
      s2 = !s2;
      Serial.print("Good message: ");
      //Serial.print(millis());
      Serial.print(" S:");
      Serial.print(readbuffer[0], HEX);
      Serial.print( " L:");
      Serial.print(readbuffer[1], DEC);
      Serial.print( " ");
      for (i = 2; i < buffer_max; i++) {
        Serial.print(readbuffer[i], HEX);
        Serial.print(" ");
      }


    } else {
      Serial.print("Invalid message. cksum: ");
      Serial.println(cksum, HEX);
      for (i = 0; i < buffer_max; i++) {
        Serial.print(readbuffer[i], HEX);
        Serial.print(" ");
      }
    }
    
    //    handleMessage(0x2D);
    Serial.println();
    // Empty the buffer
    memset(readbuffer, 0, sizeof(readbuffer));
    buffer_index = 0;
    read_byte = false;
    lastrx = millis();
  }

  // Increment index if we put something into the buffer
  if (read_byte == true) {
    read_byte = false;
    buffer_index++;
    lastrx = millis();
  }

}


void handleMessage(byte messageType) {
  byte volup[6] = { 0x50, 0x04, 0x68, 0x32, 0x11, 0x1F};
  byte voldown2[6] = { 0x50, 0x04, 0x68, 0x32, 0x10, 0x1E};
  byte voldown[6] = { 0xF0, 0x04, 0x68, 0x32, 0x10, 0xBE };
  byte pressmode[6] = { 0xF0, 0x4, 0x68, 0x48, 0x23, 0xF7 };
  byte releasemode[6] = { 0xF0, 0x4, 0x68, 0x48, 0xA3, 0x77 };
  byte ibussucks[22] = {
    0x68, 0x12, 0x3B, 0x23, 0x62, 0x10, 0x49, 0x42, 0x55,
    0x53, 0x53, 0x55, 0x43, 0x4b, 0x53, 0x20, 0x20, 0x20,
    0x20, 0x20, 0x20, 0x40
  };
  byte infoMessage[27] = {0x30, 0x19, 0x80, 0x1A, 0x35 , 0x0 , 0x20 , 0x20 , 0x43 , 0x48 , 0x45 , 0x43 , 0x4B , 0x20 , 0x43 , 0x4F , 0x4E , 0x54 , 0x52 , 0x4F , 0x4C , 0x20 , 0x4F , 0x4B , 0x20 , 0x20 , 0x83};
  // OP Was setting faultPin HIGH to write?
  // digitalWrite(faultPin, HIGH);
  switch (messageType) {
    case 0x2B: // + for vol up
      Serial.println("Sending vol up.");
      sendMessage(volup, 6);
      break;
    case 0x2D: // - for vol down
      Serial.println("Sending vol down.");
      sendMessage(voldown2, 6);
      break;
    case 0x42: // B for IBus Sucks
      Serial.println("Sending Info message.");
      sendMessage(infoMessage, 27);
      break;
    case 0x6D: // m for mode
      Serial.println("Sending Mode.");
      sendMessage(pressmode, 6);
      delay(150);
      sendMessage(releasemode, 6);
      break;
  }
 }

void sendMessage(byte message_data[], int length) {
  //byte message_cksum = gen_cksum(message_data);
  for (int k = 0; k < length ; k++) {
    Serial.write(message_data[k]);
  }
 
}
//Not used
byte gen_cksum(const byte message[]) {
  byte cksum = 0x00;
  for (int i = 1; i <= message[0]; i++) {
    cksum = cksum ^ message[i];
  }
  return cksum;
}
2

What does that mean? ... exactly

3

Im not able to send any message.

4

So you're keying commands in the serial monitor?

5

I'm using an osciloscope to see the output. But as the code is not mine, i'm not sure the conections I made are okey or if the code has some failure. I know is not an easy thing to ask

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6

Hi,
post a schematic of the project, (can be done freehand).
Understanding your project makes it easy to help.

I've never used this IC, but from the datasheet I understood that you also need to use its TX pin, but I didn't see the use of TX in your code.

7

The output of what? You only ever write to pin spin2, and this just gets toggled...

      if (s2) 
      {
        digitalWrite(spin2, HIGH);
      }
      else 
      {
        digitalWrite(spin2, LOW);
      }
      
      s2 = !s2;

Should you be writing out some serial data somewhere?

Are you sure this code actually works because it doesn't seem to be doing much?

8

I guess it doesn't work. I have found another solution using other program, i hope they cloae this theme.

9

Just mark the topic as resolved by ticking the "Solution" box on one of the posts.

10

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