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Arduino и can шина

Опубликовано: 20 декабря 2014

Audi OBD-II diagnostic interface - распиновка

CAN Bus sheild (pin)

Источник: GITHub

MCP2515.h

/*
MCP2515.h - CAN library
Written by Frank Kienast in November, 2010

Connections to MCP2515:
Arduino MCP2515
11       MOSI
12       MISO
13       SCK
10       CS
*/

#ifndef MCP2515_h
#define MCP2515_h

#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif

typedef struct
{
boolean isExtendedAdrs;
unsigned long adrsValue;
boolean rtr;
byte dataLength;
byte data[8];
} CANMSG;

class MCP2515
{
public:
static boolean initCAN(int baudConst);
static boolean setCANNormalMode(boolean singleShot);
static boolean setCANReceiveonlyMode();
static boolean receiveCANMessage(CANMSG *msg, unsigned long timeout);
static boolean transmitCANMessage(CANMSG msg, unsigned long timeout);
static byte getCANTxErrCnt();
static byte getCANRxErrCnt();
static long queryOBD(byte code);

private:
static boolean setCANBaud(int baudConst);
static void writeReg(byte regno, byte val);
static void writeRegBit(byte regno, byte bitno, byte val);
static byte readReg(byte regno);
};

//Data rate selection constants
#define CAN_BAUD_10K 1
#define CAN_BAUD_50K 2
#define CAN_BAUD_100K 3
#define CAN_BAUD_125K 4
#define CAN_BAUD_250K 5
#define CAN_BAUD_500K 6

#endif

MCP2515.cpp

/*
MCP2515.cpp - CAN library
Written by Frank Kienast in November, 2010
Modified by hooovahh in September, 2012 to fix bugs in extended addressing
and allow single variable for both regular and extended addresses.

Connections to MCP2515:
Arduino MCP2515
11       MOSI
12       MISO
13       SCK
10       CS
*/

#include "SPI.h"
#include "MCP2515.h"

#define SLAVESELECT 10

//MCP2515 Registers
#define RXF0SIDH 0x00
#define RXF0SIDL 0x01
#define RXF0EID8 0x02
#define RXF0EID0 0x03
#define RXF1SIDH 0x04
#define RXF1SIDL 0x05
#define RXF1EID8 0x06
#define RXF1EID0 0x07
#define RXF2SIDH 0x08
#define RXF2SIDL 0x09
#define RXF2EID8 0x0A
#define RXF2EID0 0x0B
#define BFPCTRL 0x0C
#define TXRTSCTRL 0x0D
#define CANSTAT 0x0E
#define CANCTRL 0x0F
#define RXF3SIDH 0x10
#define RXF3SIDL 0x11
#define RXF3EID8 0x12
#define RXF3EID0 0x13
#define RXF4SIDH 0x14
#define RXF4SIDL 0x15
#define RXF4EID8 0x16
#define RXF4EID0 0x17
#define RXF5SIDH 0x18
#define RXF5SIDL 0x19
#define RXF5EID8 0x1A
#define RXF5EID0 0x1B
#define TEC 0x1C
#define REC 0x1D
#define RXM0SIDH 0x20
#define RXM0SIDL 0x21
#define RXM0EID8 0x22
#define RXM0EID0 0x23
#define RXM1SIDH 0x24
#define RXM1SIDL 0x25
#define RXM1EID8 0x26
#define RXM1EID0 0x27
#define CNF3 0x28
#define CNF2 0x29
#define CNF1 0x2A
#define CANINTE 0x2B
#define MERRE 7
#define WAKIE 6
#define ERRIE 5
#define TX2IE 4
#define TX1IE 3
#define TX0IE 2
#define RX1IE 1
#define RX0IE 0
#define CANINTF 0x2C
#define MERRF 7
#define WAKIF 6
#define ERRIF 5
#define TX2IF 4
#define TX1IF 3
#define TX0IF 2
#define RX1IF 1
#define RX0IF 0
#define EFLG 0x2D
#define TXB0CTRL 0x30
#define TXREQ 3
#define TXB0SIDH 0x31
#define TXB0SIDL 0x32
#define EXIDE 3
#define TXB0EID8 0x33
#define TXB0EID0 0x34
#define TXB0DLC 0x35
#define TXRTR 7
#define TXB0D0 0x36

#define RXB0CTRL 0x60
#define RXM1 6
#define RXM0 5
#define RXRTR 3
// Bits 2:0 FILHIT2:0
#define RXB0SIDH 0x61
#define RXB0SIDL 0x62
#define RXB0EID8 0x63
#define RXB0EID0 0x64
#define RXB0DLC 0x65
#define RXB0D0 0x66

//MCP2515 Command Bytes
#define RESET 0xC0
#define READ 0x03
#define READ_RX_BUFFER 0x90
#define WRITE 0x02
#define LOAD_TX_BUFFER 0x40
#define RTS 0x80
#define READ_STATUS 0xA0
#define RX_STATUS 0xB0
#define BIT_MODIFY 0x05

boolean MCP2515::initCAN(int baudConst)
{
byte mode;

SPI.begin();

digitalWrite(SLAVESELECT,LOW);
SPI.transfer(RESET); //Reset cmd
digitalWrite(SLAVESELECT,HIGH);
//Read mode and make sure it is config
delay(100);
mode = readReg(CANSTAT) >> 5;
if(mode != 0b100)
return false;

return(setCANBaud(baudConst));

}

boolean MCP2515::setCANBaud(int baudConst)
{
byte brp;

//BRP<5:0> = 00h, so divisor (0+1)*2 for 125ns per quantum at 16MHz for 500K
//SJW<1:0> = 00h, Sync jump width = 1
switch(baudConst)
{
    case CAN_BAUD_500K: brp = 0; break;
    case CAN_BAUD_250K: brp = 1; break;
    case CAN_BAUD_125K: brp = 3; break;
    case CAN_BAUD_100K: brp = 4; break;
    default: return false;
}
digitalWrite(SLAVESELECT,LOW);
SPI.transfer(WRITE);
SPI.transfer(CNF1);
SPI.transfer(brp & 0b00111111);
digitalWrite(SLAVESELECT,HIGH);

//PRSEG<2:0> = 0x01, 2 time quantum for prop
//PHSEG<2:0> = 0x06, 7 time constants to PS1 sample
//SAM = 0, just 1 sampling
//BTLMODE = 1, PS2 determined by CNF3
digitalWrite(SLAVESELECT,LOW);
SPI.transfer(WRITE);
SPI.transfer(CNF2);
SPI.transfer(0b10110001);
digitalWrite(SLAVESELECT,HIGH);

//PHSEG2<2:0> = 5 for 6 time constants after sample
digitalWrite(SLAVESELECT,LOW);
SPI.transfer(WRITE);
SPI.transfer(CNF3);
SPI.transfer(0x05);
digitalWrite(SLAVESELECT,HIGH);

//SyncSeg + PropSeg + PS1 + PS2 = 1 + 2 + 7 + 6 = 16

return true;
}

boolean MCP2515::setCANNormalMode(boolean singleShot)
{
//REQOP2<2:0> = 000 for normal mode
//ABAT = 0, do not abort pending transmission
//OSM = 0, not one shot
//CLKEN = 1, disable output clock
//CLKPRE = 0b11, clk/8

byte settings;
byte mode;

settings = 0b00000111 | (singleShot << 3);

writeReg(CANCTRL,settings);
//Read mode and make sure it is normal
mode = readReg(CANSTAT) >> 5;
if(mode != 0)
return false;

return true;

}

boolean MCP2515::setCANReceiveonlyMode()
{
//REQOP2<2:0> = 011 for receive-only mode
//ABAT = 0, do not abort pending transmission
//OSM = 0, not one shot
//CLKEN = 1, disable output clock
//CLKPRE = 0b11, clk/8

byte mode;

writeReg(CANCTRL,0b01100111);
//Read mode and make sure it is receive-only
mode = readReg(CANSTAT) >> 5;
if(mode != 3)
return false;

return true;

}

boolean MCP2515::receiveCANMessage(CANMSG *msg, unsigned long timeout)
{
    unsigned long startTime, endTime;
    unsigned short standardID = 0;
boolean gotMessage;
    byte val;
    int i;

    startTime = millis();
    endTime = startTime + timeout;
    gotMessage = false;
    while(millis() < endTime)
    {
      val = readReg(CANINTF);
      //If we have a message available, read it
      if(bitRead(val,RX0IF) == 1)
      {
        gotMessage = true;
        break;
      }
    }

    if(gotMessage)
    {
      val = readReg(RXB0CTRL);
      msg->rtr = ((bitRead(val,3) == 1) ? true : false);

//Address received from

      val = readReg(RXB0SIDH);
      standardID |= (val << 3);
      val = readReg(RXB0SIDL);
      standardID |= (val >> 5);

   msg->adrsValue = long(standardID);
      msg->isExtendedAdrs = ((bitRead(val,EXIDE) == 1) ? true : false);
      if(msg->isExtendedAdrs)
      {
        msg->adrsValue = ((msg->adrsValue << 2) | (val & 0b11));
        val = readReg(RXB0EID8);
msg->adrsValue = (msg->adrsValue << 8) | val;
        val = readReg(RXB0EID0);
        msg->adrsValue = (msg->adrsValue << 8) | val;
      }
      msg->adrsValue = 0b11111111111111111111111111111 & msg->adrsValue; // mask out extra bits
      //Read data bytes
      val = readReg(RXB0DLC);
      msg->dataLength = (val & 0xf);
      digitalWrite(SLAVESELECT,LOW);
      SPI.transfer(READ);
      SPI.transfer(RXB0D0);
      for(i = 0; i < msg->dataLength; i++)
        msg->data[i] = SPI.transfer(0);
      digitalWrite(SLAVESELECT,HIGH);

      //And clear read interrupt
      writeRegBit(CANINTF,RX0IF,0);
    }

    return gotMessage;
}

boolean MCP2515::transmitCANMessage(CANMSG msg, unsigned long timeout)
{
unsigned long startTime, endTime;
boolean sentMessage;
unsigned short val;
int i;
unsigned short standardID = 0;

standardID = short(msg.adrsValue);
startTime = millis();
endTime = startTime + timeout;
sentMessage = false;
if(!msg.isExtendedAdrs)
{
//Write standard ID registers
val = standardID >> 3;
writeReg(TXB0SIDH,val);
val = standardID << 5;
writeReg(TXB0SIDL,val);
}
else
{
//Write extended ID registers, which use the standard ID registers
val = msg.adrsValue >> 21;
writeReg(TXB0SIDH,val);
val = msg.adrsValue >> 16;
val = val & 0b00000011;
val = val | (msg.adrsValue >> 13 & 0b11100000);
val |= 1 << EXIDE;
writeReg(TXB0SIDL,val);
val = msg.adrsValue >> 8;
writeReg(TXB0EID8,val);
    val = msg.adrsValue;
    writeReg(TXB0EID0,val);
}

val = msg.dataLength & 0x0f;
if(msg.rtr)
    bitWrite(val,TXRTR,1);
writeReg(TXB0DLC,val);

//Message bytes
digitalWrite(SLAVESELECT,LOW);
SPI.transfer(WRITE);
SPI.transfer(TXB0D0);
for(i = 0; i < msg.dataLength; i++)
    SPI.transfer(msg.data[i]);
digitalWrite(SLAVESELECT,HIGH);

//Transmit the message
writeRegBit(TXB0CTRL,TXREQ,1);

sentMessage = false;
while(millis() < endTime)
{
    val = readReg(CANINTF);
    if(bitRead(val,TX0IF) == 1)
    {
      sentMessage = true;
      break;
    }
}

//Abort the send if failed
writeRegBit(TXB0CTRL,TXREQ,0);

//And clear write interrupt
writeRegBit(CANINTF,TX0IF,0);

return sentMessage;

}

byte MCP2515::getCANTxErrCnt()
{
return(readReg(TEC));
}

byte MCP2515::getCANRxErrCnt()
{
return(readReg(REC));
}

void MCP2515::writeReg(byte regno, byte val)
{
digitalWrite(SLAVESELECT,LOW);
SPI.transfer(WRITE);
SPI.transfer(regno);
SPI.transfer(val);
digitalWrite(SLAVESELECT,HIGH);
}

void MCP2515::writeRegBit(byte regno, byte bitno, byte val)
{
digitalWrite(SLAVESELECT,LOW);
SPI.transfer(BIT_MODIFY);
SPI.transfer(regno);
SPI.transfer(1 << bitno);
if(val != 0)
SPI.transfer(0xff);
else
SPI.transfer(0x00);
digitalWrite(SLAVESELECT,HIGH);
}

byte MCP2515::readReg(byte regno)
{
byte val;

digitalWrite(SLAVESELECT,LOW);
SPI.transfer(READ);
SPI.transfer(regno);
val = SPI.transfer(0);
digitalWrite(SLAVESELECT,HIGH);

return val;
}

long MCP2515::queryOBD(byte code)
{
CANMSG msg;
long val;
boolean rxSuccess;
int noMatch;

msg.adrsValue = 0x7df;
msg.isExtendedAdrs = false;
msg.rtr = false;
msg.dataLength = 8;
msg.data[0] = 0x02;
msg.data[1] = 0x01;
msg.data[2] = code;
msg.data[3] = 0;
msg.data[4] = 0;
msg.data[5] = 0;
msg.data[6] = 0;
msg.data[7] = 0;

if(!transmitCANMessage(msg,1000))
return 0;

rxSuccess = receiveCANMessage(&msg,1000);
if (rxSuccess)
{
    //Check if the PIDs match (in case other messages are also on bus)
noMatch = 0;
    while(msg.data[2] != code)
{
        rxSuccess = receiveCANMessage(&msg,1000);
        noMatch++;
        if (!rxSuccess || noMatch >= 5)
{
            return 0;
        }
    }
}
else
    return 0;

if(msg.data[0] == 3)
    val = msg.data[3];
else
    val = 256 * msg.data[3] + msg.data[4];

return val;
}

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