CCS/BQ76PL455EVM: TMS570 launch pad and BQ76PL455EVM code

Tool/software: Code Composer Studio

Hi,

I am using TMS570 launchpad and BQ76PL455EVM for BMS.

I will explain you the problem in the below code snippet section.

///////////////////////////////////

nSent = WriteReg(0, 107, 0x8000, 2, FRMWRT_ALL_NR); // clear all fault summary flags

int  WriteReg(BYTE bID, uint16 wAddr, uint64 dwData, BYTE bLen, BYTE bWriteType)
{
    int bRes = 0;
    BYTE bBuf[4] = {0, 0, 0, 0};
    switch(bLen)
    {
    case 1:
        bBuf[0] =  dwData & 0x00000000000000FF;
        bRes = WriteFrame(bID, wAddr, bBuf, 1, bWriteType);
        break;
    case 2:
        bBuf[0] = (dwData & 0x000000000000FF00) >> 8;
        bBuf[1] =  dwData & 0x00000000000000FF;
        bRes = WriteFrame(bID, wAddr, bBuf, 2, bWriteType);
        break;
    case 3:
        bBuf[0] = (dwData & 0x0000000000FF0000) >> 16;
        bBuf[1] = (dwData & 0x000000000000FF00) >> 8;
        bBuf[2] =  dwData & 0x00000000000000FF;
        bRes = WriteFrame(bID, wAddr, bBuf, 3, bWriteType);
        break;
    case 4:
        bBuf[0] = (dwData & 0x00000000FF000000) >> 24;
        bBuf[1] = (dwData & 0x0000000000FF0000) >> 16;
        bBuf[2] = (dwData & 0x000000000000FF00) >> 8;
        bBuf[3] =  dwData & 0x00000000000000FF;
        bRes = WriteFrame(bID, wAddr, bBuf, 4, bWriteType);
        break;
    case 5:
        bBuf[0] = (dwData & 0x000000FF00000000) >> 32;
        bBuf[1] = (dwData & 0x00000000FF000000) >> 24;
        bBuf[2] = (dwData & 0x0000000000FF0000) >> 16;
        bBuf[3] = (dwData & 0x000000000000FF00) >> 8;
        bBuf[4] =  dwData & 0x00000000000000FF;
        bRes = WriteFrame(bID, wAddr, bBuf, 5, bWriteType);
        break;
    case 6:
        bBuf[0] = (dwData & 0x0000FF0000000000) >> 40;
        bBuf[1] = (dwData & 0x000000FF00000000) >> 32;
        bBuf[2] = (dwData & 0x00000000FF000000) >> 24;
        bBuf[3] = (dwData & 0x0000000000FF0000) >> 16;
        bBuf[4] = (dwData & 0x000000000000FF00) >> 8;
        bBuf[5] =  dwData & 0x00000000000000FF;
        bRes = WriteFrame(bID, wAddr, bBuf, 6, bWriteType);
        break;
    case 7:
        bBuf[0] = (dwData & 0x00FF000000000000) >> 48;
        bBuf[1] = (dwData & 0x0000FF0000000000) >> 40;
        bBuf[2] = (dwData & 0x000000FF00000000) >> 32;
        bBuf[3] = (dwData & 0x00000000FF000000) >> 24;
        bBuf[4] = (dwData & 0x0000000000FF0000) >> 16;
        bBuf[5] = (dwData & 0x000000000000FF00) >> 8;
        bBuf[6] =  dwData & 0x00000000000000FF;;
        bRes = WriteFrame(bID, wAddr, bBuf, 7, bWriteType);
        break;
    case 8:
        bBuf[0] = (dwData & 0xFF00000000000000) >> 56;
        bBuf[1] = (dwData & 0x00FF000000000000) >> 48;
        bBuf[2] = (dwData & 0x0000FF0000000000) >> 40;
        bBuf[3] = (dwData & 0x000000FF00000000) >> 32;
        bBuf[4] = (dwData & 0x00000000FF000000) >> 24;
        bBuf[5] = (dwData & 0x0000000000FF0000) >> 16;
        bBuf[6] = (dwData & 0x000000000000FF00) >> 8;
        bBuf[7] =  dwData & 0x00000000000000FF;
        bRes = WriteFrame(bID, wAddr, bBuf, 8, bWriteType);
        break;
    default:
        break;
    }
    return bRes;
}

int  WriteFrame(BYTE bID, uint16 wAddr, BYTE * pData, BYTE bLen, BYTE bWriteType)
{
    int       bPktLen = 0;
    BYTE   pFrame[32];
    BYTE * pBuf = pFrame;
    uint16   wCRC;

    if (bLen == 7 || bLen > 8)
        return 0;

    memset(pFrame, 0x7F, sizeof(pFrame));
    if (wAddr > 255)    {
        *pBuf++ = 0x88 | bWriteType | bLen;    // use 16-bit address
        if (bWriteType == FRMWRT_SGL_R || bWriteType == FRMWRT_SGL_NR || bWriteType == FRMWRT_GRP_R || bWriteType == FRMWRT_GRP_NR)//(bWriteType != FRMWRT_ALL_NR)// || (bWriteType != FRMWRT_ALL_R))
        {
            *pBuf++ = (bID & 0x00FF);
        }
        *pBuf++ = (wAddr & 0xFF00) >> 8;
        *pBuf++ =  wAddr & 0x00FF;
    }
    else {
        *pBuf++ = 0x80 | bWriteType | bLen;    // use 8-bit address
        if (bWriteType == FRMWRT_SGL_R || bWriteType == FRMWRT_SGL_NR || bWriteType == FRMWRT_GRP_R || bWriteType == FRMWRT_GRP_NR)
        {
            *pBuf++ = (bID & 0x00FF);
        }
        *pBuf++ = wAddr & 0x00FF;
    }

    while(bLen--)
        *pBuf++ = *pData++;

    bPktLen = pBuf - pFrame;

    wCRC = CRC16(pFrame, bPktLen);
    *pBuf++ = wCRC & 0x00FF;
    *pBuf++ = (wCRC & 0xFF00) >> 8;
    bPktLen += 2;

    sciSend(scilinREG, bPktLen, pFrame);

    return bPktLen;
}

////////////////////////////////////////

nSent gives the return value of WriteReg -- bRes.

bRes gives the return value of Writeframe -- bPktLen.

So, actually nSent gives the values of bPktLen.

If i am keeping bLen as 2, I am getting nSent as 6 and i am keeping bLen as 3, I am getting nSent as 7.

So, what is the relation between bLen and bPktLen ? Are they both not same?

Please help me out with understanding.

Thanks

Ritul Shah