obd2-interface.ino

#include <global.h>
#include <Canbus.h>
#include <mcp2515_defs.h>
#include <mcp2515.h>
#include <defaults.h>

String UserInput;
char canBuffer[456];

void sendMessage(unsigned char mode, unsigned char pid) {
  // buffer for can messages received
  char buffer[64];
  // build can message
  tCAN message;
  message.id = PID_REQUEST;
  message.header.rtr = 0;
  message.header.length = 8;
  message.data[0] = 0x02;
  message.data[1] = mode;
  message.data[2] = pid;
  message.data[3] = 0x00;
  message.data[4] = 0x00;
  message.data[5] = 0x00;
  message.data[6] = 0x00;
  message.data[7] = 0x00;

  mcp2515_bit_modify(CANCTRL, (1 << REQOP2) | (1 << REQOP1) | (1 << REQOP0), 0);
  if (mcp2515_send_message(&message)) {
    delay(500);
    if (!mcp2515_check_message()) {
      Serial.println("Error: no message received");
    }
    while (mcp2515_check_message()) {
      if (mcp2515_get_message(&message)) {
        sprintf(buffer, "0x%02X 0x%02X 0x%02X 0x%02X 0x%02X 0x%02X 0x%02X 0x%02X 0x%02X", message.id, message.data[0], message.data[1], message.data[2], message.data[3], message.data[4], message.data[5], message.data[6], message.data[7]);
        if (buffer[0] == 0) {
          Serial.println("Error: no message received");
        } else {
          Serial.println(buffer);
        }
      }
    }
  }
}

// returns true on correct input
bool checkInput(String input) {
  String val1 = input.substring(0, 4);
  String val2 = input.substring(5);
  if (val1.substring(0, 2) == "0x" && val2.substring(0, 2) == "0x") {
    if (!isHexadecimalDigit(val1.charAt(2)) || !isHexadecimalDigit(val1.charAt(3))) {
      return false;
    }
    if (!isHexadecimalDigit(val2.charAt(2)) || !isHexadecimalDigit(val2.charAt(3))) {
      return false;
    }
    return true;
  }
  return false;
}

void setup() {
  Serial.begin(9600);
  Serial.println("obd2-interface");
  Serial.println("--------------");
  if (Canbus.init(CANSPEED_500)) {
    Serial.println("can init successful");
  } else {
    Serial.println("can init failed");
    return;
  }

  Serial.println("Enter Mode and PID for your request in hex like this: 0x01 0x0D");
  Serial.println("Response in format: ID #Bytes Mode PID Ah Bh Ch Dh Unused");
  Serial.println("--------------");
}

void loop() {
  while (Serial.available()) {
    UserInput = Serial.readString();
    Serial.println("> " + UserInput);

    if (!checkInput(UserInput)) {
      Serial.println("Error: wrong format");
      break;
    }

    char input[16];
    char* pEnd;
    UserInput.toCharArray(input, 16);
    int mode = strtol(input, &pEnd, 16);
    int pid = strtol(pEnd, &pEnd, 16);
    /* additional info for dev
      char outstring[32];
      sprintf(outstring, "Mode: %d PID: %d\n", mode, pid);
      Serial.print(outstring);
    */

    sendMessage(mode, pid);
  }
}