Arduino CAN-to-JSON Listener

arduino-can-rx.ino

#include <cstdio>
#include "Arduino.h"
#include "mcp_can.h"

#define NOP()    asm("nop\n")

MCP_CAN my_can_controller(10);
const uint8_t CAN_INTERRUPT_PIN(2);

uint32_t messageId;
uint8_t messageLength;
uint8_t messageBuffer[8];

void setup()
{
   Serial.begin(115200);

   bool init_status(my_can_controller.begin(MCP_ANY, CAN_500KBPS, MCP_16MHZ));

   if (CAN_OK == init_status)
   {
      Serial.println(F("Initialized the CAN controller IC."));
   }
   else
   {
      Serial.println(F("Error initializing CAN controller IC."));
      while (true)
      {
         NOP();
      }
   }

   my_can_controller.setMode(MCP_NORMAL);
   pinMode(CAN_INTERRUPT_PIN, INPUT);
}


void loop()
{
   if (digitalRead(CAN_INTERRUPT_PIN) == false)
   {
      my_can_controller.readMsgBuf(&messageId, &messageLength, messageBuffer);

      // determine if message ID is standard length (11 bits)
      if ((messageId & 0x8000000) != 0x8000000)
      {
         Serial.print(F("{\"id:\""));
         Serial.print(messageId);
         Serial.print(F(",\"length:\""));
         Serial.print(messageLength);
         Serial.print(F(",\"bytestring:0x\""));

         uint8_t serialBuffer[2];
         for (uint8_t i = 0; i < messageLength; ++i)
         {
            sprintf(serialBuffer, "%2X", *(messageBuffer + i));
            Serial.print(serialBuffer);
         }
         Serial.print(F("}\n"));
      }
   }
}