SWCAN on the macchina M2.

SWCAN_test_m2.ino

#include <SPI.h>
#include <MCP2515_sw_can.h>

// Pin definitions specific to how the MCP2515 is wired up.
#define CS_PIN    SPI0_CS3
#define INT_PIN    SWC_INT
#define Serial SerialUSB

// Create CAN object with pins as defined
SWcan CAN(CS_PIN, INT_PIN);

void CANHandler() {
	CAN.intHandler();
}

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

  while (!Serial);

  pinMode(DS2, OUTPUT);
  pinMode(DS6, OUTPUT);
  
	Serial.println("Initializing ...");

  digitalWrite(DS2, HIGH);

	// Set up SPI Communication
	// dataMode can be SPI_MODE0 or SPI_MODE3 only for MCP2515
	SPI.setClockDivider(SPI_CLOCK_DIV2);
	SPI.setDataMode(SPI_MODE0);
	SPI.setBitOrder(MSBFIRST);
	SPI.begin();
	
	// Initialize MCP2515 CAN controller at the specified speed and clock frequency
	// (Note:  This is the oscillator attached to the MCP2515, not the Arduino oscillator)
	//speed in KHz, clock in MHz
	CAN.setupSW(33333); //GMLAN
  CAN.mode(3); // Normal on the SWCAN bus. 
  // 0 = Sleep
  // 1 = High Speed
  // 2 = High Voltage
  // 3 = Normal


	attachInterrupt(SWC_INT, CANHandler, FALLING);
	//CAN.SetRXMask(MASK0, 0x7F0, 0); //match all but bottom four bits
	//CAN.SetRXFilter(FILTER0, 0x100, 0); //allows 0x100 - 0x10F
	//So, this code will only accept frames with ID of 0x100 - 0x10F. All other frames
	//will be ignored.

	Serial.println("Ready ...");

  
}

byte i=0;

// CAN message frame (actually just the parts that are exposed by the MCP2515 RX/TX buffers)
Frame message;

void loop() {	

	if (CAN.GetRXFrame(message)) {
    digitalWrite(DS6, HIGH);

		// Print message
		Serial.print("ID: ");
		Serial.println(message.id,HEX);
		Serial.print("Extended: ");
		if(message.extended) {
			Serial.println("Yes");
		} else {
			Serial.println("No");
		}
		Serial.print("Length: ");
		Serial.println(message.length,DEC);
		for(i=0;i<message.length;i++) {
			Serial.print(message.data.byte[i],HEX);
			Serial.print(" ");
		}
		Serial.println();
		Serial.println();
    digitalWrite(DS6, LOW);

	}
}