mcp_can.cpp

/*
  mcp_can.cpp
  2012 Copyright (c) Seeed Technology Inc.  All right reserved.

  Author:Loovee
  2014-1-16
  
  Contributor: 
  
  Cory J. Fowler
  Latonita
  Woodward1
  Mehtajaghvi
  BykeBlast
  TheRo0T
  Tsipizic
  ralfEdmund
  Nathancheek
  BlueAndi
  Adlerweb
  Btetz
  Hurvajs
  
  The MIT License (MIT)

  Copyright (c) 2013 Seeed Technology Inc.

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
*/
#include "mcp_can.h"

#define spi_readwrite mcp_can_spi_transfer
#define spi_read() spi_readwrite(0x00)


byte mcp_can_spi_transfer(byte out){
	byte in;
	SPI.beginTransaction(SPISettings(4000000, MSBFIRST, SPI_MODE0));
	in = SPI.transfer(out);
	SPI.endTransaction();
	return in;
}

/*********************************************************************************************************
** Function name:           mcp2515_reset
** Descriptions:            reset the device
*********************************************************************************************************/
void MCP_CAN::mcp2515_reset(void)
{
    MCP2515_SELECT();
    spi_readwrite(MCP_RESET);
    MCP2515_UNSELECT();
    delay(10);
}

/*********************************************************************************************************
** Function name:           mcp2515_readRegister
** Descriptions:            read register
*********************************************************************************************************/
INT8U MCP_CAN::mcp2515_readRegister(const INT8U address)                                                                     
{
    INT8U ret;

    MCP2515_SELECT();
    spi_readwrite(MCP_READ);
    spi_readwrite(address);
    ret = spi_read();
    MCP2515_UNSELECT();

    return ret;
}

/*********************************************************************************************************
** Function name:           mcp2515_readRegisterS
** Descriptions:            read registerS
*********************************************************************************************************/
void MCP_CAN::mcp2515_readRegisterS(const INT8U address, INT8U values[], const INT8U n)
{
	INT8U i;
	MCP2515_SELECT();
	spi_readwrite(MCP_READ);
	spi_readwrite(address);
	// mcp2515 has auto-increment of address-pointer
	for (i=0; i<n && i<CAN_MAX_CHAR_IN_MESSAGE; i++) {
		values[i] = spi_read();
	}
	MCP2515_UNSELECT();
}

/*********************************************************************************************************
** Function name:           mcp2515_setRegister
** Descriptions:            set register
*********************************************************************************************************/
void MCP_CAN::mcp2515_setRegister(const INT8U address, const INT8U value)
{
    MCP2515_SELECT();
    spi_readwrite(MCP_WRITE);
    spi_readwrite(address);
    spi_readwrite(value);
    MCP2515_UNSELECT();
}

/*********************************************************************************************************
** Function name:           mcp2515_setRegisterS
** Descriptions:            set registerS
*********************************************************************************************************/
void MCP_CAN::mcp2515_setRegisterS(const INT8U address, const INT8U values[], const INT8U n)
{
    INT8U i;
    MCP2515_SELECT();
    spi_readwrite(MCP_WRITE);
    spi_readwrite(address);
       
    for (i=0; i<n; i++) 
    {
        spi_readwrite(values[i]);
    }
    MCP2515_UNSELECT();
}

/*********************************************************************************************************
** Function name:           mcp2515_modifyRegister
** Descriptions:            set bit of one register
*********************************************************************************************************/
void MCP_CAN::mcp2515_modifyRegister(const INT8U address, const INT8U mask, const INT8U data)
{
    MCP2515_SELECT();
    spi_readwrite(MCP_BITMOD);
    spi_readwrite(address);
    spi_readwrite(mask);
    spi_readwrite(data);
    MCP2515_UNSELECT();
}

/*********************************************************************************************************
** Function name:           mcp2515_readStatus
** Descriptions:            read mcp2515's Status
*********************************************************************************************************/
INT8U MCP_CAN::mcp2515_readStatus(void)                             
{
	INT8U i;
	MCP2515_SELECT();
	spi_readwrite(MCP_READ_STATUS);
	i = spi_read();
	MCP2515_UNSELECT();
	
	return i;
}

/*********************************************************************************************************
** Function name:           mcp2515_setCANCTRL_Mode
** Descriptions:            set control mode
*********************************************************************************************************/
INT8U MCP_CAN::mcp2515_setCANCTRL_Mode(const INT8U newmode)
{
    INT8U i;

    mcp2515_modifyRegister(MCP_CANCTRL, MODE_MASK, newmode);

    i = mcp2515_readRegister(MCP_CANCTRL);
    i &= MODE_MASK;

    if ( i == newmode ) 
    {
        return MCP2515_OK;
    }

    return MCP2515_FAIL;

}

/*********************************************************************************************************
** Function name:           mcp2515_configRate
** Descriptions:            set boadrate
*********************************************************************************************************/
INT8U MCP_CAN::mcp2515_configRate(const INT8U canSpeed)            
{
    INT8U set, cfg1, cfg2, cfg3;
    set = 1;
    switch (canSpeed)
    {
        case (CAN_5KBPS):
        cfg1 = MCP_16MHz_5kBPS_CFG1;
        cfg2 = MCP_16MHz_5kBPS_CFG2;
        cfg3 = MCP_16MHz_5kBPS_CFG3;
        break;

        case (CAN_10KBPS):
        cfg1 = MCP_16MHz_10kBPS_CFG1;
        cfg2 = MCP_16MHz_10kBPS_CFG2;
        cfg3 = MCP_16MHz_10kBPS_CFG3;
        break;

        case (CAN_20KBPS):
        cfg1 = MCP_16MHz_20kBPS_CFG1;
        cfg2 = MCP_16MHz_20kBPS_CFG2;
        cfg3 = MCP_16MHz_20kBPS_CFG3;
        break;
        
        case (CAN_25KBPS):
        cfg1 = MCP_16MHz_25kBPS_CFG1;
        cfg2 = MCP_16MHz_25kBPS_CFG2;
        cfg3 = MCP_16MHz_25kBPS_CFG3;
        break;
        
        case (CAN_31K25BPS):
        cfg1 = MCP_16MHz_31k25BPS_CFG1;
        cfg2 = MCP_16MHz_31k25BPS_CFG2;
        cfg3 = MCP_16MHz_31k25BPS_CFG3;
        break;

        case (CAN_33KBPS):
        cfg1 = MCP_16MHz_33kBPS_CFG1;
        cfg2 = MCP_16MHz_33kBPS_CFG2;
        cfg3 = MCP_16MHz_33kBPS_CFG3;
        break;

        case (CAN_40KBPS):
        cfg1 = MCP_16MHz_40kBPS_CFG1;
        cfg2 = MCP_16MHz_40kBPS_CFG2;
        cfg3 = MCP_16MHz_40kBPS_CFG3;
        break;

        case (CAN_50KBPS):
        cfg1 = MCP_16MHz_50kBPS_CFG1;
        cfg2 = MCP_16MHz_50kBPS_CFG2;
        cfg3 = MCP_16MHz_50kBPS_CFG3;
        break;

        case (CAN_80KBPS):
        cfg1 = MCP_16MHz_80kBPS_CFG1;
        cfg2 = MCP_16MHz_80kBPS_CFG2;
        cfg3 = MCP_16MHz_80kBPS_CFG3;
        break;

        case (CAN_83K3BPS):
        cfg1 = MCP_16MHz_83k3BPS_CFG1;
        cfg2 = MCP_16MHz_83k3BPS_CFG2;
        cfg3 = MCP_16MHz_83k3BPS_CFG3;
        break;  

        case (CAN_95KBPS):
        cfg1 = MCP_16MHz_95kBPS_CFG1;
        cfg2 = MCP_16MHz_95kBPS_CFG2;
        cfg3 = MCP_16MHz_95kBPS_CFG3;
        break;

        case (CAN_100KBPS):                                             /* 100KBPS                  */
        cfg1 = MCP_16MHz_100kBPS_CFG1;
        cfg2 = MCP_16MHz_100kBPS_CFG2;
        cfg3 = MCP_16MHz_100kBPS_CFG3;
        break;

        case (CAN_125KBPS):
        cfg1 = MCP_16MHz_125kBPS_CFG1;
        cfg2 = MCP_16MHz_125kBPS_CFG2;
        cfg3 = MCP_16MHz_125kBPS_CFG3;
        break;

        case (CAN_200KBPS):
        cfg1 = MCP_16MHz_200kBPS_CFG1;
        cfg2 = MCP_16MHz_200kBPS_CFG2;
        cfg3 = MCP_16MHz_200kBPS_CFG3;
        break;

        case (CAN_250KBPS):
        cfg1 = MCP_16MHz_250kBPS_CFG1;
        cfg2 = MCP_16MHz_250kBPS_CFG2;
        cfg3 = MCP_16MHz_250kBPS_CFG3;
        break;

        case (CAN_500KBPS):
        cfg1 = MCP_16MHz_500kBPS_CFG1;
        cfg2 = MCP_16MHz_500kBPS_CFG2;
        cfg3 = MCP_16MHz_500kBPS_CFG3;
        break;
        
	case (CAN_666KBPS):
        cfg1 = MCP_16MHz_666kBPS_CFG1;
        cfg2 = MCP_16MHz_666kBPS_CFG2;
        cfg3 = MCP_16MHz_666kBPS_CFG3;
        break;
        
        case (CAN_1000KBPS):
        cfg1 = MCP_16MHz_1000kBPS_CFG1;
        cfg2 = MCP_16MHz_1000kBPS_CFG2;
        cfg3 = MCP_16MHz_1000kBPS_CFG3;
        break;  

        default:
        set = 0;
        break;
    }

    if (set) {
        mcp2515_setRegister(MCP_CNF1, cfg1);
        mcp2515_setRegister(MCP_CNF2, cfg2);
        mcp2515_setRegister(MCP_CNF3, cfg3);
        return MCP2515_OK;
    }
    else {
        return MCP2515_FAIL;
    }
}

/*********************************************************************************************************
** Function name:           mcp2515_initCANBuffers
** Descriptions:            init canbuffers
*********************************************************************************************************/
void MCP_CAN::mcp2515_initCANBuffers(void)
{
    INT8U i, a1, a2, a3;

    a1 = MCP_TXB0CTRL;
    a2 = MCP_TXB1CTRL;
    a3 = MCP_TXB2CTRL;
    for (i = 0; i < 14; i++) {                                          /* in-buffer loop               */
        mcp2515_setRegister(a1, 0);
        mcp2515_setRegister(a2, 0);
        mcp2515_setRegister(a3, 0);
        a1++;
        a2++;
        a3++;
    }
    mcp2515_setRegister(MCP_RXB0CTRL, 0);
    mcp2515_setRegister(MCP_RXB1CTRL, 0);
}

/*********************************************************************************************************
** Function name:           mcp2515_init
** Descriptions:            init the device
*********************************************************************************************************/
INT8U MCP_CAN::mcp2515_init(const INT8U canSpeed)                       /* mcp2515init                  */
{

  INT8U res;

    mcp2515_reset();

    res = mcp2515_setCANCTRL_Mode(MODE_CONFIG);
    if(res > 0)
    {
#if DEBUG_MODE
      Serial.print("Enter setting mode fall\r\n"); 
#else
      delay(10);
#endif
      return res;
    }
#if DEBUG_MODE
    Serial.print("Enter setting mode success \r\n");
#else
    delay(10);
#endif

                                                                        /* set boadrate                 */
    if(mcp2515_configRate(canSpeed))
    {
#if DEBUG_MODE
      Serial.print("set rate fall!!\r\n");
#else
      delay(10);
#endif
      return res;
    }
#if DEBUG_MODE
    Serial.print("set rate success!!\r\n");
#else
    delay(10);
#endif

    if ( res == MCP2515_OK ) {

                                                                        /* init canbuffers              */
        mcp2515_initCANBuffers();

                                                                        /* interrupt mode               */
        mcp2515_setRegister(MCP_CANINTE, MCP_RX0IF | MCP_RX1IF);

#if (DEBUG_RXANY==1)
                                                                        /* enable both receive-buffers  */
                                                                        /* to receive any message       */
                                                                        /* and enable rollover          */
        mcp2515_modifyRegister(MCP_RXB0CTRL,
        MCP_RXB_RX_MASK | MCP_RXB_BUKT_MASK,
        MCP_RXB_RX_ANY | MCP_RXB_BUKT_MASK);
        mcp2515_modifyRegister(MCP_RXB1CTRL, MCP_RXB_RX_MASK,
        MCP_RXB_RX_ANY);
#else
                                                                        /* enable both receive-buffers  */
                                                                        /* to receive messages          */
                                                                        /* with std. and ext. identifie */
                                                                        /* rs                           */
                                                                        /* and enable rollover          */
        mcp2515_modifyRegister(MCP_RXB0CTRL,
        MCP_RXB_RX_MASK | MCP_RXB_BUKT_MASK,
        MCP_RXB_RX_STDEXT | MCP_RXB_BUKT_MASK );
        mcp2515_modifyRegister(MCP_RXB1CTRL, MCP_RXB_RX_MASK,
        MCP_RXB_RX_STDEXT);
#endif
                                                                        /* enter normal mode            */
        res = mcp2515_setCANCTRL_Mode(MODE_NORMAL);                                                                
        if(res)
        {
#if DEBUG_MODE        
          Serial.print("Enter Normal Mode Fall!!\r\n");
#else
            delay(10);
#endif           
          return res;
        }


#if DEBUG_MODE
          Serial.print("Enter Normal Mode Success!!\r\n");
#else
            delay(10);
#endif

    }
    return res;

}

/*********************************************************************************************************
** Function name:           mcp2515_write_id
** Descriptions:            write can id
*********************************************************************************************************/
void MCP_CAN::mcp2515_write_id( const INT8U mcp_addr, const INT8U ext, const INT32U id )
{
    uint16_t canid;
    INT8U tbufdata[4];

    canid = (uint16_t)(id & 0x0FFFF);

    if ( ext == 1) 
    {
        tbufdata[MCP_EID0] = (INT8U) (canid & 0xFF);
        tbufdata[MCP_EID8] = (INT8U) (canid >> 8);
        canid = (uint16_t)(id >> 16);
        tbufdata[MCP_SIDL] = (INT8U) (canid & 0x03);
        tbufdata[MCP_SIDL] += (INT8U) ((canid & 0x1C) << 3);
        tbufdata[MCP_SIDL] |= MCP_TXB_EXIDE_M;
        tbufdata[MCP_SIDH] = (INT8U) (canid >> 5 );
    }
    else 
    {
        tbufdata[MCP_SIDH] = (INT8U) (canid >> 3 );
        tbufdata[MCP_SIDL] = (INT8U) ((canid & 0x07 ) << 5);
        tbufdata[MCP_EID0] = 0;
        tbufdata[MCP_EID8] = 0;
    }
    mcp2515_setRegisterS( mcp_addr, tbufdata, 4 );
}

/*********************************************************************************************************
** Function name:           mcp2515_read_id
** Descriptions:            read can id
*********************************************************************************************************/
void MCP_CAN::mcp2515_read_id( const INT8U mcp_addr, INT8U* ext, INT32U* id )
{
    INT8U tbufdata[4];

    *ext = 0;
    *id = 0;

    mcp2515_readRegisterS( mcp_addr, tbufdata, 4 );

    *id = (tbufdata[MCP_SIDH]<<3) + (tbufdata[MCP_SIDL]>>5);

    if ( (tbufdata[MCP_SIDL] & MCP_TXB_EXIDE_M) ==  MCP_TXB_EXIDE_M ) 
    {
                                                                        /* extended id                  */
        *id = (*id<<2) + (tbufdata[MCP_SIDL] & 0x03);
        *id = (*id<<8) + tbufdata[MCP_EID8];
        *id = (*id<<8) + tbufdata[MCP_EID0];
        *ext = 1;
    }
}

/*********************************************************************************************************
** Function name:           mcp2515_write_canMsg
** Descriptions:            write msg
*********************************************************************************************************/
void MCP_CAN::mcp2515_write_canMsg( const INT8U buffer_sidh_addr)
{
    INT8U mcp_addr;
    mcp_addr = buffer_sidh_addr;
    mcp2515_setRegisterS(mcp_addr+5, m_nDta, m_nDlc );                  /* write data bytes             */
    if ( m_nRtr == 1)                                                   /* if RTR set bit in byte       */
    {
        m_nDlc |= MCP_RTR_MASK;  
    }
    mcp2515_setRegister((mcp_addr+4), m_nDlc );                        /* write the RTR and DLC        */
    mcp2515_write_id(mcp_addr, m_nExtFlg, m_nID );                     /* write CAN id                 */

}

/*********************************************************************************************************
** Function name:           mcp2515_read_canMsg
** Descriptions:            read message
*********************************************************************************************************/
void MCP_CAN::mcp2515_read_canMsg( const INT8U buffer_sidh_addr)        /* read can msg                 */
{
    INT8U mcp_addr, ctrl;

    mcp_addr = buffer_sidh_addr;

    mcp2515_read_id( mcp_addr, &m_nExtFlg,&m_nID );

    ctrl = mcp2515_readRegister( mcp_addr-1 );
    m_nDlc = mcp2515_readRegister( mcp_addr+4 );

    if ((ctrl & 0x08)) {
        m_nRtr = 1;
    }
    else {
        m_nRtr = 0;
    }

    m_nDlc &= MCP_DLC_MASK;
    mcp2515_readRegisterS( mcp_addr+5, &(m_nDta[0]), m_nDlc );
}

/*********************************************************************************************************
** Function name:           mcp2515_start_transmit
** Descriptions:            start transmit
*********************************************************************************************************/
void MCP_CAN::mcp2515_start_transmit(const INT8U mcp_addr)              /* start transmit               */
{
    mcp2515_modifyRegister( mcp_addr-1 , MCP_TXB_TXREQ_M, MCP_TXB_TXREQ_M );
}

/*********************************************************************************************************
** Function name:           mcp2515_getNextFreeTXBuf
** Descriptions:            get Next free txbuf
*********************************************************************************************************/
INT8U MCP_CAN::mcp2515_getNextFreeTXBuf(INT8U *txbuf_n)                 /* get Next free txbuf          */
{
    INT8U res, i, ctrlval;
    INT8U ctrlregs[MCP_N_TXBUFFERS] = { MCP_TXB0CTRL, MCP_TXB1CTRL, MCP_TXB2CTRL };

    res = MCP_ALLTXBUSY;
    *txbuf_n = 0x00;

                                                                        /* check all 3 TX-Buffers       */
    for (i=0; i<MCP_N_TXBUFFERS; i++) {
        ctrlval = mcp2515_readRegister( ctrlregs[i] );
        if ( (ctrlval & MCP_TXB_TXREQ_M) == 0 ) {
            *txbuf_n = ctrlregs[i]+1;                                   /* return SIDH-address of Buffe */
                                                                        /* r                            */
            res = MCP2515_OK;
            return res;                                                 /* ! function exit              */
        }
    }
    return res;
}

/*********************************************************************************************************
** Function name:           set CS
** Descriptions:            init CS pin and set UNSELECTED
*********************************************************************************************************/
MCP_CAN::MCP_CAN(INT8U _CS)
{
    SPICS = _CS;
    pinMode(SPICS, OUTPUT);
    MCP2515_UNSELECT();
}

/*********************************************************************************************************
** Function name:           init
** Descriptions:            init can and set speed
*********************************************************************************************************/
INT8U MCP_CAN::begin(INT8U speedset)
{
    INT8U res;

    SPI.begin();
    res = mcp2515_init(speedset);
    if (res == MCP2515_OK) return CAN_OK;
    else return CAN_FAILINIT;
}

/*********************************************************************************************************
** Function name:           init_Mask
** Descriptions:            init canid Masks
*********************************************************************************************************/
INT8U MCP_CAN::init_Mask(INT8U num, INT8U ext, INT32U ulData)
{
    INT8U res = MCP2515_OK;
#if DEBUG_MODE
    Serial.print("Begin to set Mask!!\r\n");
#else
    delay(10);
#endif
    res = mcp2515_setCANCTRL_Mode(MODE_CONFIG);
    if(res > 0){
#if DEBUG_MODE
    Serial.print("Enter setting mode fall\r\n"); 
#else
    delay(10);
#endif
    return res;
    }
    
    if (num == 0){
        mcp2515_write_id(MCP_RXM0SIDH, ext, ulData);

    }
    else if(num == 1){
        mcp2515_write_id(MCP_RXM1SIDH, ext, ulData);
    }
    else res =  MCP2515_FAIL;
    
    res = mcp2515_setCANCTRL_Mode(MODE_NORMAL);
    if(res > 0){
#if DEBUG_MODE
    Serial.print("Enter normal mode fall\r\n"); 
#else
    delay(10);
#endif
    return res;
  }
#if DEBUG_MODE
    Serial.print("set Mask success!!\r\n");
#else
    delay(10);
#endif
    return res;
}

/*********************************************************************************************************
** Function name:           init_Filt
** Descriptions:            init canid filters
*********************************************************************************************************/
INT8U MCP_CAN::init_Filt(INT8U num, INT8U ext, INT32U ulData)
{
    INT8U res = MCP2515_OK;
#if DEBUG_MODE
    Serial.print("Begin to set Filter!!\r\n");
#else
    delay(10);
#endif
    res = mcp2515_setCANCTRL_Mode(MODE_CONFIG);
    if(res > 0)
    {
#if DEBUG_MODE
      Serial.print("Enter setting mode fall\r\n"); 
#else
      delay(10);
#endif
      return res;
    }
    
    switch( num )
    {
        case 0:
        mcp2515_write_id(MCP_RXF0SIDH, ext, ulData);
        break;

        case 1:
        mcp2515_write_id(MCP_RXF1SIDH, ext, ulData);
        break;

        case 2:
        mcp2515_write_id(MCP_RXF2SIDH, ext, ulData);
        break;

        case 3:
        mcp2515_write_id(MCP_RXF3SIDH, ext, ulData);
        break;

        case 4:
        mcp2515_write_id(MCP_RXF4SIDH, ext, ulData);
        break;

        case 5:
        mcp2515_write_id(MCP_RXF5SIDH, ext, ulData);
        break;

        default:
        res = MCP2515_FAIL;
    }
    
    res = mcp2515_setCANCTRL_Mode(MODE_NORMAL);
    if(res > 0)
    {
#if DEBUG_MODE
      Serial.print("Enter normal mode fall\r\nSet filter fail!!\r\n"); 
#else
      delay(10);
#endif
      return res;
    }
#if DEBUG_MODE
    Serial.print("set Filter success!!\r\n");
#else
    delay(10);
#endif
    
    return res;
}

/*********************************************************************************************************
** Function name:           setMsg
** Descriptions:            set can message, such as dlc, id, dta[] and so on
*********************************************************************************************************/
INT8U MCP_CAN::setMsg(INT32U id, INT8U ext, INT8U len, INT8U rtr, INT8U *pData)
{
    m_nExtFlg = ext;
    m_nID     = id;
    m_nDlc    = min( len, MAX_CHAR_IN_MESSAGE );
    m_nRtr    = rtr;
    for(int i = 0; i<m_nDlc; i++)
    {
        m_nDta[i] = *(pData+i);
    }
    return MCP2515_OK;
}


/*********************************************************************************************************
** Function name:           setMsg
** Descriptions:            set can message, such as dlc, id, dta[] and so on
*********************************************************************************************************/
INT8U MCP_CAN::setMsg(INT32U id, INT8U ext, INT8U len, INT8U *pData)
{
    return setMsg( id, ext, len, 0, pData );
}

/*********************************************************************************************************
** Function name:           clearMsg
** Descriptions:            set all message to zero
*********************************************************************************************************/
INT8U MCP_CAN::clearMsg()
{
    m_nID       = 0;
    m_nDlc      = 0;
    m_nExtFlg   = 0;
    m_nRtr      = 0;
    m_nfilhit   = 0;
    for(int i = 0; i<m_nDlc; i++ )
      m_nDta[i] = 0x00;

    return MCP2515_OK;
}

/*********************************************************************************************************
** Function name:           sendMsg
** Descriptions:            send message
*********************************************************************************************************/
INT8U MCP_CAN::sendMsg()
{
    INT8U res, res1, txbuf_n;
    uint16_t uiTimeOut = 0;

    do {
        res = mcp2515_getNextFreeTXBuf(&txbuf_n);                       /* info = addr.                 */
        uiTimeOut++;
    } while (res == MCP_ALLTXBUSY && (uiTimeOut < TIMEOUTVALUE));

    if(uiTimeOut == TIMEOUTVALUE) 
    {   
        return CAN_GETTXBFTIMEOUT;                                      /* get tx buff time out         */
    }
    uiTimeOut = 0;
    mcp2515_write_canMsg( txbuf_n);
    mcp2515_start_transmit( txbuf_n );
    do
    {
        uiTimeOut++;        
        res1= mcp2515_readRegister(txbuf_n-1 /* the ctrl reg is located at txbuf_n-1 */);  /* read send buff ctrl reg 	*/
        res1 = res1 & 0x08;                               		
    }while(res1 && (uiTimeOut < TIMEOUTVALUE));   
    if(uiTimeOut == TIMEOUTVALUE)                                       /* send msg timeout             */	
    {
        return CAN_SENDMSGTIMEOUT;
    }
    return CAN_OK;

}

/*********************************************************************************************************
** Function name:           sendMsgBuf
** Descriptions:            send buf
*********************************************************************************************************/
INT8U MCP_CAN::sendMsgBuf(INT32U id, INT8U ext, INT8U rtr, INT8U len, INT8U *buf)
{
    setMsg(id, ext, len, rtr, buf);
    return sendMsg();
}

/*********************************************************************************************************
** Function name:           sendMsgBuf
** Descriptions:            send buf
*********************************************************************************************************/
INT8U MCP_CAN::sendMsgBuf(INT32U id, INT8U ext, INT8U len, INT8U *buf)
{
    setMsg(id, ext, len, buf);
    return sendMsg();
}


/*********************************************************************************************************
** Function name:           readMsg
** Descriptions:            read message
*********************************************************************************************************/
INT8U MCP_CAN::readMsg()
{
    INT8U stat, res;

    stat = mcp2515_readStatus();

    if ( stat & MCP_STAT_RX0IF )                                        /* Msg in Buffer 0              */
    {
        mcp2515_read_canMsg( MCP_RXBUF_0);
        mcp2515_modifyRegister(MCP_CANINTF, MCP_RX0IF, 0);
        res = CAN_OK;
    }
    else if ( stat & MCP_STAT_RX1IF )                                   /* Msg in Buffer 1              */
    {
        mcp2515_read_canMsg( MCP_RXBUF_1);
        mcp2515_modifyRegister(MCP_CANINTF, MCP_RX1IF, 0);
        res = CAN_OK;
    }
    else 
    {
        res = CAN_NOMSG;
    }
    return res;
}

/*********************************************************************************************************
** Function name:           readMsgBuf
** Descriptions:            read message buf
*********************************************************************************************************/
INT8U MCP_CAN::readMsgBuf(INT8U *len, INT8U buf[])
{
    INT8U  rc;
    
    rc = readMsg();
    
    if (rc == CAN_OK) {
       *len = m_nDlc;
       for(int i = 0; i<m_nDlc; i++) {
         buf[i] = m_nDta[i];
       } 
    } else {
       	 *len = 0;
    }
    return rc;
}

/*********************************************************************************************************
** Function name:           readMsgBufID
** Descriptions:            read message buf and can bus source ID
*********************************************************************************************************/
INT8U MCP_CAN::readMsgBufID(INT32U *ID, INT8U *len, INT8U buf[])
{
    INT8U rc;
    rc = readMsg();

    if (rc == CAN_OK) {
       *len = m_nDlc;
       *ID  = m_nID;
       for(int i = 0; i<m_nDlc && i < MAX_CHAR_IN_MESSAGE; i++) {
          buf[i] = m_nDta[i];
       }
    } else {
       *len = 0;
    }
    return rc;
}

/*********************************************************************************************************
** Function name:           checkReceive
** Descriptions:            check if got something
*********************************************************************************************************/
INT8U MCP_CAN::checkReceive(void)
{
    INT8U res;
    res = mcp2515_readStatus();                                         /* RXnIF in Bit 1 and 0         */
    if ( res & MCP_STAT_RXIF_MASK ) 
    {
        return CAN_MSGAVAIL;
    }
    else 
    {
        return CAN_NOMSG;
    }
}

/*********************************************************************************************************
** Function name:           checkError
** Descriptions:            if something error
*********************************************************************************************************/
INT8U MCP_CAN::checkError(void)
{
    INT8U eflg = mcp2515_readRegister(MCP_EFLG);

    if ( eflg & MCP_EFLG_ERRORMASK ) 
    {
        return CAN_CTRLERROR;
    }
    else 
    {
        return CAN_OK;
    }
}

/*********************************************************************************************************
** Function name:           getCanId
** Descriptions:            when receive something you can get the can id!!
*********************************************************************************************************/
INT32U MCP_CAN::getCanId(void)
{
    return m_nID;
} 

/*********************************************************************************************************
** Function name:           isRemoteRequest
** Descriptions:            when receive something you can check if it was a request
*********************************************************************************************************/
INT8U MCP_CAN::isRemoteRequest(void)
{
    return m_nRtr;
} 

/*********************************************************************************************************
** Function name:           isExtendedFrame
** Descriptions:            did we just receive standard 11bit frame or extended 29bit? 0 = std, 1 = ext
*********************************************************************************************************/
INT8U MCP_CAN::isExtendedFrame(void)
{
    return m_nExtFlg;
} 

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