//开关输入寄存器，可读

eMBErrorCode

eMBRegDiscreteCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNDiscrete )

{

//错误状态

eMBErrorCode eStatus = MB_ENOERR;

//操作寄存器个数

int16_t iNDiscrete = ( int16_t )usNDiscrete;

//偏移量

uint16_t usBitOffset;

//判断寄存器时候再制定范围内

if( ( (int16_t)usAddress >= REG_DISCRETE_START ) &&( usAddress + usNDiscrete <= REG_DISCRETE_START + REG_DISCRETE_SIZE ) )

{

//获得偏移量

usBitOffset = ( uint16_t )( usAddress - REG_DISCRETE_START );

while( iNDiscrete > 0 )

{

*pucRegBuffer++ = xMBUtilGetBits( ucRegDiscreteBuf, usBitOffset,( uint8_t)( iNDiscrete > 8 ? 8 : iNDiscrete ) );

iNDiscrete -= 8;

usBitOffset += 8;

}

}

else

{

eStatus = MB_ENOREG;

}

return eStatus;

}

其中这一段怎么解释呢*pucRegBuffer++ = xMBUtilGetBits( ucRegDiscreteBuf, usBitOffset,( uint8_t)( iNDiscrete > 8 ? 8 : iNDiscrete ) );

还有我对应用层数量，01 02 03 04 05 06等等功能码在哪里定义的呢