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发表于 2018-3-12 09:22:39
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/**
* Modbus master holding register callback function.
*
* @param pucRegBuffer holding register buffer
* @param usAddress holding register address
* @param usNRegs holding register number
* @param eMode read or write
*
* @return result
*/
eMBErrorCode eMBMasterRegHoldingCB(UCHAR * pucRegBuffer, USHORT usAddress,
USHORT usNRegs, eMBRegisterMode eMode)
{
eMBErrorCode eStatus = MB_ENOERR;
USHORT iRegIndex;
USHORT * pusRegHoldingBuf;
USHORT REG_HOLDING_START;
USHORT REG_HOLDING_NREGS;
USHORT usRegHoldStart;
pusRegHoldingBuf = usMRegHoldBuf[ucMBMasterGetDestAddress() - 1];
REG_HOLDING_START = M_REG_HOLDING_START;
REG_HOLDING_NREGS = M_REG_HOLDING_NREGS;
usRegHoldStart = usMRegHoldStart;
/* if mode is read, the master will write the received date to buffer. */
eMode = MB_REG_WRITE;
/* it already plus one in modbus function method. */
usAddress--;
if ((usAddress >= REG_HOLDING_START)
&& (usAddress + usNRegs <= REG_HOLDING_START + REG_HOLDING_NREGS))
{
iRegIndex = usAddress - usRegHoldStart;
switch (eMode)
{
/* read current register values from the protocol stack. */
case MB_REG_READ:
while (usNRegs > 0)
{
*pucRegBuffer++ = (UCHAR) (pusRegHoldingBuf[iRegIndex] >> 8);
*pucRegBuffer++ = (UCHAR) (pusRegHoldingBuf[iRegIndex] & 0xFF);
iRegIndex++;
usNRegs--;
}
break;
/* write current register values with new values from the protocol stack. */
case MB_REG_WRITE:
while (usNRegs > 0)
{
pusRegHoldingBuf[iRegIndex] = *pucRegBuffer++ << 8;
pusRegHoldingBuf[iRegIndex] |= *pucRegBuffer++;
iRegIndex++;
usNRegs--;
}
break;
}
}
else
{
eStatus = MB_ENOREG;
}
return eStatus;
}
/**
主机模式的eMBMasterRegHoldingCB函数里的红色部分，被强制为写了，对吗？去掉这句，读回来的数据会被清掉，怎么解决？
**/ |
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楼主: sunnydragon
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