51单片机的MODBUS C语言程序(从机)

crc16(uint8 //puchMsg, usDataLen)

{

uint8 uchCRCHi = 0xFF ; /// 高CRC字节初始化 ///

uint8 uchCRCLo = 0xFF ; /// 低CRC 字节初始化 ///

uint32 uIndex ; /// CRC循环中的索引 ///

while (usDataLen--) /// 传输消息缓冲区 ///

{

uIndex = uchCRCHi ^ //puchMsg++ ; /// 计算CRC ///

uchCRCHi = uchCRCLo ^ auchCRCHi[uIndex] ;

uchCRCLo = auchCRCLo[uIndex] ;

}

return (uchCRCHi < 8 | uchCRCLo) ;

}//uint16 crc16(uint8 //puchMsg, uint16 usDataLen)

//开始发送

void beginSend(void)

{

b485Send = 1; //设为发送

sendPosi = 0;

if(sendCount > 1)

sendCount--;

ACC = sendBuf[0];

TB8 = P;

SBUF = sendBuf[0];

}//void beginSend(void)

//读线圈状态

void readCoil(void)

{

uint8 addr;

uint8 tempAddr;

uint8 byteCount;

uint8 bitCount;

uint16 crcData;

uint8 position;

uint8 i,k;

uint8 result;

uint16 tempData;

uint8 exit = 0;

//addr = (receBuf[2]<8) + receBuf[3];

//tempAddr = addr & 0xfff;

addr = receBuf[3];

tempAddr = addr;

//bitCount = (receBuf[4]<8) + receBuf[5]; //读取的位个数

bitCount = receBuf[5];

byteCount = bitCount / 8; //字节个数

if(bitCount%8 != 0)

byteCount++;

for(k=0;k

{//字节位置

position = k + 3;

sendBuf[position] = 0;

for(i=0;i<8;i++)

{

getCoilVal(tempAddr,&tempData);

sendBuf[position] |= tempData < i;

tempAddr++;

if(tempAddr >= addr+bitCount)

{ //读完

exit = 1;

break;

}

}

if(exit == 1)

break;

}

sendBuf[0] = localAddr;

sendBuf[1] = 0x01;

sendBuf[2] = byteCount;

byteCount += 3;

crcData = crc16(sendBuf,byteCount);

sendBuf[byteCount] = crcData >> 8;

byteCount++;

sendBuf[byteCount] = crcData & 0xff;

sendCount = byteCount + 1;

beginSend();

}//void readCoil(void)

//读寄存器

void readRegisters(void)

{

uint8 addr;

uint8 tempAddr;

uint16 result;

uint16 crcData;

uint8 readCount;

uint8 byteCount;

uint8 finsh; //1完成 0出错

uint16 i;

uint16 tempData = 0;

//addr = (receBuf[2]<8) + receBuf[3];

//tempAddr = addr & 0xfff;

addr = receBuf[3];

tempAddr = addr;

//readCount = (receBuf[4]<8) + receBuf[5]; //要读的个数

readCount = receBuf[5];

byteCount = readCount // 2;

for(i=0;i

{

getRegisterVal(tempAddr,&tempData);

sendBuf[i+3] = tempData >> 8;

sendBuf[i+4] = tempData & 0xff;

}

sendBuf[0] = localAddr;

sendBuf[1] = 3;

sendBuf[2] = byteCount;

byteCount += 3;

crcData = crc16(sendBuf,byteCount);

sendBuf[byteCount] = crcData >> 8;

byteCount++;

sendBuf[byteCount] = crcData & 0xff;

sendCount = byteCount + 1;

beginSend();

}//void readRegisters(void)

//强制单个线圈

void forceSingleCoil(void)

{

uint8 addr;

uint8 tempAddr;

uint16 tempData;

uint8 onOff;

uint8 i;

//addr = (receBuf[2]<8) + receBuf[3];

//tempAddr = addr & 0xfff;

addr = receBuf[3];

tempAddr = addr;

//onOff = (receBuf[4]<8) + receBuf[5];

onOff = receBuf[4];

//if(onOff == 0xff00)

if(onOff == 0xff)

{ //设为ON

tempData = 1;

}

//else if(onOff == 0x0000)

else if(onOff == 0x00)

{ //设为OFF

tempData = 0;

}

setCoilVal(tempAddr,tempData);

for(i=0;i

{

sendBuf[i] = receBuf[i];

}

sendCount = receCount;

beginSend();

}//void forceSingleCoil(void)

//设置多个寄存器

void presetMultipleRegisters(void)

{

uint8 addr;

uint8 tempAddr;

uint8 byteCount;

uint8 setCount;

uint16 crcData;

uint16 tempData;

uint8 finsh; //为1时完成 为0时出错

uint8 i;

//addr = (receBuf[2]<8) + receBuf[3];

//tempAddr = addr & 0xfff;

addr = receBuf[3];

tempAddr = addr & 0xff;

//setCount = (receBuf[4]<8) + receBuf[5];

setCount = receBuf[5];

byteCount = receBuf[6];

for(i=0;i

{

tempData = (receBuf[i//2+7]<8) + receBuf[i//2+8];

setRegisterVal(tempAddr,tempData);

}

sendBuf[0] = localAddr;

sendBuf[1] = 16;

sendBuf[2] = addr >> 8;

sendBuf[3] = addr & 0xff;

sendBuf[4] = setCount >> 8;

sendBuf[5] = setCount & 0xff;

crcData = crc16(sendBuf,6);

sendBuf[6] = crcData >> 8;

sendBuf[7] = crcData & 0xff;

sendCount = 8;

beginSend();

}//void presetMultipleRegisters(void)

//检查uart0数据

void checkComm0Modbus(void)

{

uint16 crcData;

uint16 tempData;

if(receCount > 4)

{

switch(receBuf[1])