DFR0370 CAN BUS Shield Example Code for Arduino

In this section we will demonstrate basic CAN BUS receiving and sending functions. Receiving uses polling mode. You can accept any ID standard data frame or extended frame. The transmitting node sends a standard data frame which ID is 0x06 per 100ms.

Hardware Preparation

Item	SKU / Model	Qty	Link
Arduino UNO	Arduino UNO	2	Purchase
CAN-BUS Shield V2	DFR0370	2	Purchase
Dupont Cable	—	4	—

Software Preparation

Item	Version / Description	Link
Arduino IDE	v1.6.5	Download
CAN-BUS Shield Library	MCP2515 (v2.0)	GitHub
Installation Tutorial	Arduino IDE Library Installation	View Guide

Wiring Diagram

DFR0370 WIRING DIAGRAM

Other Preparation Work

Install the CAN-BUS Shield v2.0 Library in Arduino IDE.
Ensure the power switch on the shield is set correctly (OFF for Arduino power, ON for DB9 power).
Connect the CAN-H and CAN-L lines between the two shields using Dupont cables.

Sample Code

Receiver Code

/******************************************************************************
* demo: CAN-BUS Shield, receive data with check mode
* send data coming to fast, such as less than 10ms, you can use this way
* Jansion, 2015.5.27
******************************************************************************/
#include <SPI.h>
#include "df_can.h"
const int SPI_CS_PIN = 10;
MCPCAN CAN(SPI_CS_PIN);                                    // Set CS pin
void setup()
{
      Serial.begin(115200);
      int count = 50;                                     // the max numbers of initializint the CAN-BUS, if initialize failed first!.
      do {
          CAN.init();   //must initialize the Can interface here!
          if(CAN_OK == CAN.begin(CAN_500KBPS))                   // init can bus : baudrate = 500k
          {
              Serial.println("DFROBOT's CAN BUS Shield init ok!");
              break;
          }
          else
          {
              Serial.println("DFROBOT's CAN BUS Shield init fail");
              Serial.println("Please Init CAN BUS Shield again");

              delay(100);
              if (count <= 1)
                  Serial.println("Please give up trying!, trying is useless!");
          }

      }while(count--);

}
void loop()
{
      unsigned char len = 0;
      unsigned char buf[8];

      if(CAN_MSGAVAIL == CAN.checkReceive())            // check if data coming
      {
          CAN.readMsgBuf(&len, buf);    // read data,  len: data length, buf: data buf

          for(int i = 0; i<len; i++)    // print the data
          {
              Serial.print(buf[i]);
              Serial.print("\t");
          }
          Serial.println();
      }
}

Sender Code

// demo: CAN-BUS Shield, send data
#include <df_can.h>
#include <SPI.h>

const int SPI_CS_PIN = 10;

MCPCAN CAN(SPI_CS_PIN);                                    // Set CS pin

void setup()
{
    Serial.begin(115200);
    int count = 50;                                     // the max numbers of initializint the CAN-BUS, if initialize failed first!.
    do {
        CAN.init();   //must initialize the Can interface here!
        if(CAN_OK == CAN.begin(CAN_500KBPS))                   // init can bus : baudrate = 500k
        {
            Serial.println("DFROBOT's CAN BUS Shield init ok!");
            break;
        }
        else
        {
            Serial.println("DFROBOT's CAN BUS Shield init fail");
            Serial.println("Please Init CAN BUS Shield again");

            delay(100);
            if (count <= 1)
                Serial.println("Please give up trying!, trying is useless!");
        }

    }while(count--);

}

unsigned char data[8] = {'D', 'F', 'R', 'O', 'B', 'O', 'T', '!'};
void loop()
{
    // send data:  id = 0x06, standrad flame, data len = 8, data: data buf
    CAN.sendMsgBuf(0x06, 0, 8, data);
    delay(100);                       // send data per 100ms
}

Result

Receiver serial port output shows the incoming data frame:
DFR0370

Example Code for Arduino-Basic CAN BUS Polling Mode