Example Code for Arduino-Basic CAN BUS Interrupt Mode

Hardware Preparation

Software Preparation

Wiring Diagram

Other Preparation Work

Same as Basic CAN BUS Polling Mode, plus connect the interrupt pin (INT0) of the shield to the Arduino's digital pin 2.

Sample Code

Receiver Code

/***********************************************************
*demo: CAN-BUS Shield, receive data with interrupt mode
* when in interrupt mode, the data coming can't be too fast, must >20ms, or else you can use check mode
* 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

unsigned char flagRecv = 0;
unsigned char len = 0;
unsigned char buf[8];
char str[20];

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--);

    attachInterrupt(0, MCP2515_ISR, FALLING); // start interrupt
}

void MCP2515_ISR()
{
    flagRecv = 1;
}

void loop()
{
    if(flagRecv)
    {                                   // check if get data
        flagRecv = 0;                   // clear flag
        // iterate over all pending messages
        while (CAN_MSGAVAIL == CAN.checkReceive())
        {
            CAN.readMsgBuf(&len, buf);
            for(int i = 0; i<len; i++)
            {
                Serial.print(buf[i]);Serial.print("\t");
            }
            Serial.println();
        }
    }
}

Sender Code

Same as Basic CAN BUS Polling Mode.

Result

Receiver serial port output shows incoming data frame:

Additional Information

Use this mode for data transmission intervals >20ms. For faster data, use polling mode.