Example Code for Arduino-CAN Data Logging to SD Card

Hardware Preparation

Software Preparation

plus SD Library (included in Arduino IDE).

Wiring Diagram

Other Preparation Work

1. Insert a formatted Micro SD card into the shield's SD card slot.
2. Ensure the SD card is properly seated and the SPI CS pin for SD is set to 4.

Sample Code

Receiver Code

/**************************************************************************************************************
*demo: CAN-BUS Shield, receive data with interrupt mode, and set mask and filter
* 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"
#include <SD.h>

const int SPI_CS_PIN =10;
MCPCAN CAN(SPI_CS_PIN);
unsigned char flagRecv=0;
unsigned char len=0;
unsigned char buf[8];
char str[20];
char sd_cspin=4;
File myFile;

void setup()
{
    Serial.begin(115200);
    int count=50;
    Serial.print("Initializing can controlor...");
    do {
        CAN.init();
        CAN.init_Mask(MCP_RXM0,0,0x3ff);
        CAN.init_Mask(MCP_RXM1,0,0x3ff);
        CAN.init_Filter(MCP_RXF0,0,0x04);
        CAN.init_Filter(MCP_RXF1,0,0x05);
        CAN.init_Filter(MCP_RXF2,0,0x60);
        CAN.init_Filter(MCP_RXF3,0,0x07);
        CAN.init_Filter(MCP_RXF4,0,0x08);
        CAN.init_Filter(MCP_RXF5,0,0x09);
        if(CAN_OK == CAN.begin(CAN_500KBPS))
        {
            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);
    
    Serial.print("Initializing SD card...");
    if(!SD.begin(sd_cspin))
    {
        Serial.println("initialization failed!");
        return;
    }
    Serial.println("initialization success!");
    myFile = SD.open("Node0x60.txt", FILE_WRITE);
    if(!myFile)
    {
        Serial.println("open Node0x60.text failed!");
    }
    else
    {
        Serial.println("open Node0x60.text success!");
    }
}

void MCP2515_ISR()
{
    flagRecv=1;
}

char filewrite=1, fileread=0;
int i=0,j=0;
void loop()
{
    if(flagRecv)
    {
        flagRecv=0;
        CAN.readMsgBuf(&len, buf);
        if(filewrite)
        {
            if(i++ <1)
            {
                myFile.write(buf, len);
            }
            else
            {
                myFile.close();
                filewrite=0;
                myFile=SD.open("Node0x60.txt", FILE_WRITE);
                if(SD.exists("Node0x60.txt"))
                {
                    Serial.println("example.txt exists.");
                    fileread=1;
                }
                else
                {
                    Serial.println("example.txt doesn't exist.");
                }
            }
        }
        if(fileread)
        {
            Serial.println("printf the data that myFile has saved! ");
            myFile.read(buf, len);
            Serial.println((char *)buf);
            Serial.println("");
            myFile.close();
            Serial.println("myFile closed!!!!");
            fileread=0;
        }
    }
}

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);

void setup()
{
    Serial.begin(115200);
    int count=50;
    do {
        CAN.init();
        if(CAN_OK == CAN.begin(CAN_500KBPS))
        {
            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()
{
    CAN.sendMsgBuf(0x60,0,8,data);
    delay(1000);
}

Result

Receiver serial port output shows the saved data from the SD card:

Additional Information

This example uses the shield's integrated SD card slot to log CAN data for later analysis.