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

  Author:Loovee
  Contributor: Cory J. Fowler
  2014-1-16
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-
  1301  USA
*/
#include "mcp_can.h"

// #define spi_readwrite SPI.transfer
#define spi_read() spi_readwrite(0x00)

/*********************************************************************************************************
** 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++)
    {
        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_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_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_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;

    INT8U std = 0;
    INT8U ext = 1;
    INT32U ulMask = 0x00, ulFilt = 0x00;

    mcp2515_write_id(MCP_RXM0SIDH, ext, ulMask); /*Set both masks to 0           */
    mcp2515_write_id(MCP_RXM1SIDH, ext, ulMask); /*Mask register ignores ext bit */

    /* Set all filters to 0         */
    mcp2515_write_id(MCP_RXF0SIDH, ext, ulFilt); /* RXB0: extended               */
    mcp2515_write_id(MCP_RXF1SIDH, std, ulFilt); /* RXB1: standard               */
    mcp2515_write_id(MCP_RXF2SIDH, ext, ulFilt); /* RXB2: extended               */
    mcp2515_write_id(MCP_RXF3SIDH, std, ulFilt); /* RXB3: standard               */
    mcp2515_write_id(MCP_RXF4SIDH, ext, ulFilt);
    mcp2515_write_id(MCP_RXF5SIDH, std, ulFilt);

    /* Clear, deactivate the three  */
    /* transmit buffers             */
    /* TXBnCTRL -> TXBnD7           */
    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");
#endif
        return res;
    }
#if DEBUG_MODE
    Serial.print("Enter setting mode success \r\n");
#endif

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

#if DEBUG_MODE
        Serial.print("Enter Normal Mode Success!!\r\n");
#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:           sendMsg
** Descriptions:            send message
*********************************************************************************************************/
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:           sendMsg
** Descriptions:            send message
*********************************************************************************************************/
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");
#endif
    res = mcp2515_setCANCTRL_Mode(MODE_CONFIG);
    if (res > 0)
    {
#if DEBUG_MODE
        Serial.print("Enter setting mode fall\r\n");
#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");
#endif
        return res;
    }
#if DEBUG_MODE
    Serial.print("set Mask success!!\r\n");
#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");
#endif
    res = mcp2515_setCANCTRL_Mode(MODE_CONFIG);
    if (res > 0)
    {
#if DEBUG_MODE
        Serial.print("Enter setting mode fall\r\n");
#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");
#endif
        return res;
    }
#if DEBUG_MODE
    Serial.print("set Filter success!!\r\n");
#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 *pData)
{
    int i = 0;
    m_nExtFlg = ext;
    m_nID = id;
    m_nDlc = len;
    for (i = 0; i < MAX_CHAR_IN_MESSAGE; i++)
        m_nDta[i] = *(pData + i);
    return MCP2515_OK;
}

/*********************************************************************************************************
** 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); /* 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 len, INT8U *buf)
{
    setMsg(id, ext, len, buf);
    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[])
{
    readMsg();
    *len = m_nDlc;
    for (int i = 0; i < m_nDlc; i++)
    {
        buf[i] = m_nDta[i];
    }
}

/*********************************************************************************************************
** 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 ,u can get the can id!!
*********************************************************************************************************/
INT32U MCP_CAN::getCanId(void)
{
    return m_nID;
}
/*********************************************************************************************************
  END FILE
*********************************************************************************************************/