// 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
// loovee, 2014-6-13

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


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

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;
    }

    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
        // If either the bus is saturated or the MCU is busy,
        // both RX buffers may be in use and reading a single
        // message does not clear the IRQ conditon.
        while (CAN_MSGAVAIL == CAN.checkReceive()) 
        {
            // read data,  len: data length, buf: data buf
            CAN.readMsgBuf(&len, buf);

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

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