Example CAN code guidance

Using Arduino Programming Questions
1

Hi,

I have got an example code to send CAN messages from Here. However when I try to compile it, it says: cannot declare variable 'CAN' to be abstract type 'MCP_CAN'. I have included the library from github etc and even rolled back the IDE to 1.8.3 which it was tested on.

Is there anything else I could try?

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

// the cs pin of the version after v1.1 is default to D9
// v0.9b and v1.0 is default D10
const int SPI_CS_PIN = 9;

MCP_CAN CAN(SPI_CS_PIN);                                    // Set CS pin

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

START_INIT:

    if(CAN_OK == CAN.begin(CAN_500KBPS))                   // init can bus : baudrate = 500k
    {
        Serial.println("CAN BUS Shield init ok!");
    }
    else
    {
        Serial.println("CAN BUS Shield init fail");
        Serial.println("Init CAN BUS Shield again");
        delay(100);
        goto START_INIT;
    }
}

unsigned char stmp[8] = {0, 1, 2, 3, 4, 5, 6, 7};
void loop()
{
    // send data:  id = 0x00, standrad frame, data len = 8, stmp: data buf
    CAN.sendMsgBuf(0x00, 0, 8, stmp);
    delay(100);                       // send data per 100ms
}

/*********************************************************************************************************
  END FILE
*********************************************************************************************************/

Thanks!

2

The library examples use CAN0, not CAN. Perhaps it's already in use for something else.

3

There are MANY 'MCP2015' libraries. I was able to get it to compile with "CAN-BUS Shield by Seeed Studio" but had to change two lines:

#include <mcp_can.h>
MCP_CAN CAN(10);

were changed to:

#include <mcp2515_can.h>
mcp2515_can CAN(10); // Set CS pin
4

Try the examples included with the library by Cory Fowler work. without changes.

5

Thanks all, I've compiled the code below fine now and transmitted first signal !! :grinning: Library here

// CAN Send Example
//

#include <mcp_can.h>
#include <SPI.h>

MCP_CAN CAN0(10);     // Set CS to pin 10

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

  // Initialize MCP2515 running at 16MHz with a baudrate of 500kb/s and the masks and filters disabled.
  if(CAN0.begin(MCP_ANY, CAN_500KBPS, MCP_16MHZ) == CAN_OK) Serial.println("MCP2515 Initialized Successfully!");
  else Serial.println("Error Initializing MCP2515...");

  CAN0.setMode(MCP_NORMAL);   // Change to normal mode to allow messages to be transmitted
}

byte data[8] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};

void loop()
{
  // send data:  ID = 0x100, Standard CAN Frame, Data length = 8 bytes, 'data' = array of data bytes to send
  byte sndStat = CAN0.sendMsgBuf(0x100, 0, 8, data);
  if(sndStat == CAN_OK){
    Serial.println("Message Sent Successfully!");
  } else {
    Serial.println("Error Sending Message...");
  }
  delay(100);   // send data per 100ms
}

/*********************************************************************************************************
  END FILE
*********************************************************************************************************/
6

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