关于51单片机上实现modbus协议

自己用单片机做的Modbus从机，可以使用STC89C52。

实现了命令码为1、2、3、4、5、6的功能，程序中有些是我们部分其他功能的函数和数据，希望大家参考下编程的思想.uint Switch=0xbc95;//开关状态uchar bdata Coil1=0xff,Coil2=0xbc；//16位线圈状态sbit Coil1_bit0=Coil1^0；sbit Coil1_bit1=Coil1^1;sbit Coil1_bit2=Coil1^2;sbit Coil1_bit3=Coil1^3;sbit Coil1_bit4=Coil1^4；sbit Coil1_bit5=Coil1^5；sbit Coil1_bit6=Coil1^6；sbit Coil1_bit7=Coil1^7；sbit Coil2_bit8=Coil2^0；sbit Coil2_bit9=Coil2^1;sbit Coil2_bit10=Coil2^2;sbit Coil2_bit11=Coil2^3；sbit Coil2_bit12=Coil2^4；sbit Coil2_bit13=Coil2^5；sbit Coil2_bit14=Coil2^6；sbit Coil2_bit15=Coil2^7;uint idata ReOnlybuf[]={0x00，0x01,0x02，0x03，0x04,0x05,0x06，0x07，0x08，0x09,0x0a,0x0b,0x0c，0x0d，0x0e,0x0f｝；uint idata ReWrbuf[］=｛0x00,0x01,0x02,0x03，0x04，0x05,0x06，0x07,0x08,0x09，0x0a，0x0b，0x0c，0x0d，0x0e,0x0f｝；//CRC校验查表码值const uchar code auchCRCHi[] =｛0x00，0xC1, 0x81，0x40，0x01，0xC0, 0x80, 0x41, 0x01, 0xC0，0x80，0x41, 0x00, 0xC1，0x81，0x40, 0x01，0xC0, 0x80, 0x41,0x00，0xC1，0x81，0x40，0x00，0xC1, 0x81，0x40, 0x01, 0xC0，0x80，0x41，0x01，0xC0, 0x80, 0x41，0x00, 0xC1，0x81，0x40, 0x00, 0xC1, 0x81, 0x40，0x01，0xC0，0x80，0x41，0x00, 0xC1，0x81，0x40, 0x01，0xC0，0x80, 0x41，0x01，0xC0, 0x80，0x41,0x00，0xC1，0x81, 0x40, 0x01, 0xC0，0x80, 0x41, 0x00, 0xC1,0x81，0x40，0x00, 0xC1，0x81, 0x40, 0x01，0xC0，0x80，0x41,0x00，0xC1, 0x81，0x40，0x01，0xC0，0x80，0x41，0x01, 0xC0，0x80，0x41，0x00, 0xC1，0x81, 0x40, 0x00，0xC1, 0x81, 0x40，0x01，0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41，0x00，0xC1，0x81，0x40, 0x01，0xC0，0x80，0x41，0x00，0xC1, 0x81，0x40, 0x00，0xC1, 0x81，0x40，0x01，0xC0, 0x80, 0x41，0x01, 0xC0，0x80，0x41, 0x00，0xC1，0x81, 0x40, 0x00, 0xC1，0x81，0x40，0x01, 0xC0, 0x80, 0x41，0x00，0xC1，0x81，0x40, 0x01，0xC0，0x80, 0x41，0x01，0xC0，0x80, 0x41, 0x00, 0xC1，0x81, 0x40，0x00，0xC1，0x81, 0x40，0x01，0xC0, 0x80，0x41，0x01, 0xC0，0x80, 0x41，0x00，0xC1, 0x81，0x40, 0x01，0xC0, 0x80, 0x41，0x00，0xC1，0x81，0x40，0x00，0xC1, 0x81, 0x40，0x01, 0xC0，0x80，0x41，0x00，0xC1，0x81, 0x40, 0x01，0xC0，0x80，0x41，0x01, 0xC0，0x80，0x41, 0x00，0xC1，0x81, 0x40，0x01, 0xC0，0x80, 0x41，0x00，0xC1, 0x81，0x40, 0x00, 0xC1，0x81, 0x40,0x01，0xC0，0x80，0x41，0x01, 0xC0，0x80, 0x41, 0x00, 0xC1,0x81，0x40, 0x00，0xC1, 0x81, 0x40, 0x01, 0xC0，0x80, 0x41,0x00, 0xC1, 0x81，0x40，0x01，0xC0，0x80，0x41，0x01, 0xC0，0x80, 0x41, 0x00, 0xC1, 0x81，0x40};const uchar code auchCRCLo［］= ｛0x00，0xC0，0xC1，0x01，0xC3, 0x03，0x02，0xC2, 0xC6, 0x06,0x07, 0xC7，0x05，0xC5, 0xC4, 0x04，0xCC, 0x0C, 0x0D, 0xCD，0x0F, 0xCF，0xCE，0x0E, 0x0A, 0xCA，0xCB，0x0B, 0xC9，0x09,0x08，0xC8，0xD8，0x18，0x19，0xD9, 0x1B, 0xDB, 0xDA，0x1A，0x1E，0xDE，0xDF, 0x1F, 0xDD, 0x1D, 0x1C，0xDC，0x14，0xD4,0xD5，0x15, 0xD7，0x17, 0x16, 0xD6，0xD2，0x12, 0x13, 0xD3，0x11，0xD1，0xD0，0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33，0xF3,0xF2，0x32，0x36, 0xF6, 0xF7，0x37, 0xF5，0x35, 0x34, 0xF4,0x3C, 0xFC，0xFD，0x3D，0xFF, 0x3F, 0x3E，0xFE，0xFA, 0x3A，0x3B，0xFB，0x39，0xF9, 0xF8，0x38，0x28, 0xE8, 0xE9，0x29，0xEB, 0x2B，0x2A，0xEA, 0xEE, 0x2E，0x2F，0xEF, 0x2D, 0xED,0xEC，0x2C，0xE4, 0x24，0x25, 0xE5, 0x27，0xE7，0xE6, 0x26,0x22，0xE2, 0xE3, 0x23，0xE1，0x21, 0x20, 0xE0，0xA0, 0x60，0x61，0xA1, 0x63，0xA3, 0xA2, 0x62, 0x66，0xA6, 0xA7，0x67,0xA5, 0x65，0x64，0xA4, 0x6C, 0xAC, 0xAD，0x6D, 0xAF，0x6F，0x6E, 0xAE, 0xAA, 0x6A, 0x6B，0xAB, 0x69，0xA9, 0xA8，0x68,0x78，0xB8, 0xB9，0x79，0xBB, 0x7B, 0x7A, 0xBA，0xBE，0x7E,0x7F，0xBF，0x7D, 0xBD, 0xBC, 0x7C，0xB4, 0x74, 0x75，0xB5,0x77, 0xB7，0xB6, 0x76, 0x72, 0xB2, 0xB3，0x73, 0xB1，0x71,0x70，0xB0，0x50, 0x90, 0x91，0x51，0x93, 0x53，0x52, 0x92，0x96，0x56，0x57, 0x97, 0x55，0x95，0x94, 0x54，0x9C, 0x5C，0x5D, 0x9D，0x5F, 0x9F，0x9E, 0x5E，0x5A，0x9A，0x9B, 0x5B，0x99, 0x59，0x58，0x98，0x88，0x48，0x49, 0x89, 0x4B，0x8B，0x8A, 0x4A, 0x4E，0x8E, 0x8F, 0x4F，0x8D, 0x4D, 0x4C, 0x8C，0x44，0x84, 0x85，0x45, 0x87，0x47, 0x46, 0x86，0x82，0x42,0x43，0x83，0x41, 0x81, 0x80，0x40};/****＊＊*＊*＊＊*＊＊＊＊＊****＊＊***＊*＊＊*＊*＊**＊＊**＊**＊Function：CRC校验子函数Input:要校验的数组起始地址长度Output：16位校验码(高位在前）＊*＊＊*＊＊＊*＊＊*＊＊＊**＊*＊＊*＊***********＊＊*******＊/uint crccheck(uchar *puchMsg, uchar usDataLen）{uchar uchCRCHi = 0xFF ;uchar uchCRCLo = 0xFF ；uchar uIndex ;while （usDataLen--){uIndex = uchCRCHi ^ ＊puchMsg++ ;uchCRCHi = uchCRCLo ^ auchCRCHi［uIndex］;uchCRCLo = auchCRCLo［uIndex］；}return (uchCRCHi 〈〈8 ｜uchCRCLo）；｝/*＊**＊**＊＊*＊＊**＊**＊＊**＊*＊*******＊**＊*＊*＊＊*＊** Function:读线圈状态子函数Input：无Output：无***＊*＊*＊**＊**＊***＊*＊*＊＊*＊*＊*＊＊＊*＊＊**＊＊**＊*＊*/void ReadCoil(void）{uint StartAddress,tempAddress;uchar CoilNum,i，ByteNum，j;uchar CoilVal;bit exit=0；StartAddress=resvbuf［2];StartAddress=StartAddress|resvbuf[3]；tempAddress=StartAddress;CoilNum=resvbuf［5］；//读取的位数ByteNum=CoilNum/8;if（CoilNum%8!=0)ByteNum++;Sendbuf[2］=ByteNum;//返回的字节数if（resvbuf[1］==0x01){for(i=0；i〈ByteNum;i++）｛Sendbuf[i+3]=0;for（j=0；j〈8;j++){CoilVal=GetCoilVal(StartAddress）;Sendbuf［i+3］｜=CoilVal<〈j；StartAddress++；if（StartAddress〉=tempAddress+CoilNum)｛exit=1；break;｝｝if(exit==1）break；}}else if(resvbuf[1]==0x02)｛for（i=0;i<ByteNum;i++）｛Sendbuf[i+3]=0；for(j=0；j〈8;j++)｛CoilVal=GetSWVal（StartAddress)；Sendbuf[i+3］|=CoilVal<<j；StartAddress++；if(StartAddress>=tempAddress+CoilNum){exit=1;break;｝｝if(exit==1）break；｝｝SendCount=5+ByteNum；SendData（)；}/*＊***＊***＊***＊*＊***＊******＊＊***＊＊＊*＊**＊＊**＊＊Function：读寄存器状态子函数Input：无Output:无＊＊＊＊**＊**＊*＊*＊＊**＊＊＊＊**＊***＊*＊**＊*＊*＊＊＊**＊＊＊/void ReadRegisters(void)｛uint StartAddress;uchar ByteCount，i；StartAddress=resvbuf[2］;StartAddress=StartAddress〈〈8｜resvbuf［3]；ByteCount=resvbuf［5］*2；Sendbuf[2]=resvbuf［5];if（resvbuf［1］==0x03）for(i=0；i<ByteCount;i+=2）{Sendbuf［i+4］=ReWrbuf［StartAddress］&0xff；Sendbuf［i+3]=ReWrbuf［StartAddress］>〉8；StartAddress++;｝else if（resvbuf［1]==0x04）for（i=0;i〈ByteCount；i+=2){Sendbuf［i+4］=ReOnlybuf[StartAddress］；Sendbuf[i+3］=ReOnlybuf[StartAddress］；StartAddress++；｝SendCount=ByteCount+5；SendData()；}/*＊*＊＊*＊＊*＊*＊＊**＊****＊＊*＊＊＊＊**＊＊***＊**＊＊*＊＊**Function：强制单线圈子函数Input:无Output：无**＊*＊＊＊*＊***＊＊＊*＊*＊*＊*＊******＊********＊＊＊**＊/ void ForceSingalCoil(void){uint Address,OnOff；bit temp,CoilVal；Address=resvbuf[2］〈<8|resvbuf[3］;OnOff=resvbuf［4]<<8｜resvbuf［5］;if（OnOff==0x0000){CoilVal=0;temp=SetCoilVal(Address,CoilVal）；}else if(OnOff==0xFF00）{CoilVal=1；temp=SetCoilVal（Address，CoilVal);}if（temp==1)｛Sendbuf[2]=resvbuf［2]；Sendbuf［3]=resvbuf[3］;Sendbuf[4]=resvbuf[4]；Sendbuf［5]=resvbuf［5]；SendCount=8；SendData();}elseError=1；}/＊＊＊＊*＊*＊＊＊＊*＊＊***＊*＊＊*＊＊＊＊***＊＊＊*＊＊***＊＊****Function：强制单寄存器子函数Input:无Output：无＊＊**＊＊＊*＊**＊**＊＊＊*＊**＊＊*＊＊＊*＊＊****＊＊＊＊*＊**＊＊/void SetOneRegisterVal（）｛uint R_Address,RegisterVal;bit temp1;R_Address=resvbuf［2];R_Address=R_Address<〈8|resvbuf[3］;RegisterVal=resvbuf［4];RegisterVal=RegisterVal<<8|resvbuf［5］；temp1=SetRegisterVal（R_Address，RegisterVal）；if（temp1==1){Sendbuf[2］=resvbuf[2］；Sendbuf［3]=resvbuf[3］；Sendbuf[4］=resvbuf［4］；Sendbuf[5]=resvbuf［5］;SendCount=8；SendData()；｝elseError=1;｝/*＊＊*＊＊**＊***＊*＊*＊＊＊*＊*＊***＊**＊＊＊＊*＊＊*＊＊*****Function：读线圈值子函数Input：线圈地址Output:线圈的值*****＊＊**＊＊＊**＊＊＊*＊＊*****＊**＊*＊**＊**＊**＊*＊*＊/uchar GetCoilVal（uint Address）{uint CoilAddress;uchar CoilVal=0;CoilAddress=Address;switch（CoilAddress＆0x0f)｛case 0：CoilVal=Coil1_bit0;break；case 1：CoilVal=Coil1_bit1；break；case 2: CoilVal=Coil1_bit2;break;case 3：CoilVal=Coil1_bit3;break；case 4: CoilVal=Coil1_bit4；break;case 5: CoilVal=Coil1_bit5;break；case 6：CoilVal=Coil1_bit6;break;case 7: CoilVal=Coil1_bit7；break；case 8：CoilVal=Coil2_bit8；break；case 9: CoilVal=Coil2_bit9；break;case 10: CoilVal=Coil2_bit10;break；case 11: CoilVal=Coil2_bit11；break;case 12： CoilVal=Coil2_bit12;break；case 13： CoilVal=Coil2_bit13;break;case 14: CoilVal=Coil2_bit14；break；case 15： CoilVal=Coil2_bit15;break；default：break；｝return CoilVal;｝/＊＊*＊＊＊*＊**＊*＊＊****＊＊＊********＊*＊＊*＊***＊＊＊***Function：读开关值子函数Input：开关地址Output：开关值*******＊＊＊＊＊*＊＊*＊＊＊*＊＊＊*＊＊＊＊＊***＊**＊＊＊＊*＊*＊*/uchar GetSWVal（uint Address1){uchar CoilVal;uchar SW1，SW2=0xff；SW1=P2；Switch=SW2〈〈8｜SW1;switch(Address1＆0x0f)｛case 0: CoilVal=Switch&0x01;break；case 1：CoilVal=Switch>>1＆0x01；break；case 2：CoilVal=Switch>〉2＆0x01；break；case 3：CoilVal=Switch>>3＆0x01；break；case 4：CoilVal=Switch〉〉4＆0x01;break;case 5: CoilVal=Switch>〉5&0x01;break；case 6: CoilVal=Switch>>6&0x01;break;case 7：CoilVal=Switch〉>7＆0x01;break;case 8：CoilVal=Switch>〉8＆0x01;break;case 9：CoilVal=Switch〉>9&0x01;break;case 10： CoilVal=Switch>>10＆0x01;break;case 11： CoilVal=Switch〉〉11&0x01;break;case 12: CoilVal=Switch>〉12＆0x01；break;case 13: CoilVal=Switch〉>13＆0x01；break；case 14： CoilVal=Switch>〉14&0x01；break;case 15： CoilVal=Switch〉〉15＆0x01;break；default: break;｝return CoilVal；｝/＊*＊**＊＊*************＊*＊***＊＊＊*＊*＊＊*＊***＊＊＊*＊Function：强制单线圈值子函数Input:线圈地址，强制值Output：结果值*＊*＊＊*＊＊*＊**＊＊＊*＊*＊*＊＊*＊＊＊＊＊***＊＊＊***＊＊*＊＊＊*/bit SetCoilVal（uint Address，bit Val）{bit result=1;switch（Address＆0x0f)｛case 0: Coil1_bit0=Val；break;case 1: Coil1_bit1=Val;break;case 2：Coil1_bit2=Val；break;case 3: Coil1_bit3=Val；break;case 4: Coil1_bit4=Val;break；case 5：Coil1_bit5=Val;break；case 6: Coil1_bit6=Val;break；case 7：Coil1_bit7=Val;break；case 8：Coil2_bit8=Val;break;case 9: Coil2_bit9=Val；break;case 10： Coil2_bit10=Val；break；case 11: Coil2_bit11=Val;break;case 12： Coil2_bit12=Val；break;case 13： Coil2_bit13=Val；break；case 14: Coil2_bit14=Val；break；case 15： Coil2_bit15=Val;break；default: result=0;break;}P1=Coil1;return result；｝/***＊****＊＊*＊＊＊*＊********＊＊＊＊＊＊＊**＊***＊＊＊****Function：设置单寄存器值子函数Input:寄存器地址，值Output：结果值＊＊**＊＊＊＊****＊*＊**＊＊＊*＊＊＊**＊**＊******＊＊＊＊＊*＊＊/bit SetRegisterVal（uint Address1,uint Val1）｛uchar Addr；bit result1=1;Addr=Address1&0x0f;if（Addr<16）ReWrbuf[Addr］=Val1；elseresult1=0;return result1; ｝。

modbus.c＃i nclude "main.h"//字地址0 - 255 (只取低8位)//位地址0 - 255 (只取低8位)/* CRC 高位字节值表*/const uint8 code auchCRCHi[] = {0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40} ;/* CRC低位字节值表*/const uint8 code auchCRCLo[] = {0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3, 0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26, 0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5, 0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C, 0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83, 0x41, 0x81, 0x80, 0x40} ;uint8 testCoil; //用于测试位地址1uint16 testRegister; //用于测试字址址16uint8 localAddr = 1; //单片机控制板的地址uint8 sendCount; //发送字节个数uint8 receCount; //接收到的字节个数uint8 sendPosi; //发送位置uint16 crc16(uint8 *puchMsg, uint16 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 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<byteCount;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)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 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<byteCount;i+=2,tempAddr++){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ONtempData = 1;}//else if(onOff == 0x0000) else if(onOff == 0x00){ //设为OFFtempData = 0;}setCoilVal(tempAddr,tempData);for(i=0;i<receCount;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<setCount;i++,tempAddr++){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]){case 1://读取线圈状态(读取点16位以内)case 3://读取保持寄存器(一个或多个)case 5://强制单个线圈case 6://设置单个寄存器if(receCount >= 8){//接收完成一组数据//应该关闭接收中断if(receBuf[0]==localAddr && checkoutError==0){crcData = crc16(receBuf,6);if(crcData == receBuf[7]+(receBuf[6]<<8)) {//校验正确if(receBuf[1] == 1){//读取线圈状态(读取点16位以内)readCoil();}else if(receBuf[1] == 3){//读取保持寄存器(一个或多个)readRegisters();}else if(receBuf[1] == 5){//强制单个线圈forceSingleCoil();}else if(receBuf[1] == 6){//presetSingleRegister();}}}receCount = 0;checkoutError = 0;}break;case 15://设置多个线圈tempData = receBuf[6];tempData += 9; //数据个数if(receCount >= tempData){if(receBuf[0]==localAddr && checkoutError==0){crcData = crc16(receBuf,tempData-2);if(crcData == (receBuf[tempData-2]<<8)+ receBuf[tempData-1]) {//forceMultipleCoils();}}receCount = 0;checkoutError = 0;}break;case 16://设置多个寄存器tempData = (receBuf[4]<<8) + receBuf[5];tempData = tempData * 2; //数据个数tempData += 9;if(receCount >= tempData){if(receBuf[0]==localAddr && checkoutError==0){crcData = crc16(receBuf,tempData-2);if(crcData == (receBuf[tempData-2]<<8)+ receBuf[tempData-1]) {presetMultipleRegisters();}}receCount = 0;checkoutError = 0;}break;default:break;}}}//void checkComm0(void)//取线圈状态返回0表示成功uint16 getCoilVal(uint16 addr,uint16 *tempData){uint16 result = 0;uint16 tempAddr;tempAddr = addr & 0xfff;//只取低8位地址switch(tempAddr & 0xff){case 0:break;case 1:*tempData = testCoil;break;case 2:break;case 3:break;case 4:break;case 5:break;case 6:break;case 7:break;case 8:break;case 9:break;case 10:break;case 11:break;case 12:break;case 13:break;case 14:break;case 15:break;case 16:break;default:break;}return result;}//uint16 getCoilVal(uint16 addr,uint16 *data)//设定线圈状态返回0表示成功uint16 setCoilVal(uint16 addr,uint16 tempData) {uint16 result = 0;uint16 tempAddr;tempAddr = addr & 0xfff;switch(tempAddr & 0xff) {case 0:break;case 1:testCoil = tempData;break;case 2:break;case 3:break;case 4:break;case 5:break;case 6:break;case 7:break;case 8:break;case 9:break;case 10:break;case 11:break;case 12:break;case 13:break;case 14:break;case 15:break;case 16:break;default:break;}return result;}//uint16 setCoilVal(uint16 addr,uint16 data)//取寄存器值返回0表示成功uint16 getRegisterVal(uint16 addr,uint16 *tempData) {uint16 result = 0;uint16 tempAddr;tempAddr = addr & 0xfff;switch(tempAddr & 0xff){case 0:break; case 1:break; case 2:break; case 3:break; case 4:break; case 5:break; case 6:break; case 7:break; case 8:break; case 9:break; case 10:break; case 11:break; case 12:break;case 13:break;case 14:break;case 15:break;case 16:*tempData = testRegister;break;default:break;}return result;}//uint16 getRegisterVal(uint16 addr,uint16 &data) //设置寄存器值返回0表示成功uint16 setRegisterVal(uint16 addr,uint16 tempData) {uint16 result = 0;uint16 tempAddr;tempAddr = addr & 0xfff;switch(tempAddr & 0xff){break; case 1: break; case 2: break; case 3: break; case 4: break; case 5: break; case 6: break; case 7: break; case 8: break; case 9: break; case 10: break; case 11: break; case 12: break;break;case 14:break;case 15:break;case 16:testRegister = tempData;break;default:break;}return result;}//uint8 setRegisterVal(uint16 addr,uint16 data)。

modbus协议--51端程序的实现RTU需要一个定时器来判断3.5个流逝时间。

#define ENABLE 1#define DISABLE 0#define TRUE 1#define FAULT 0#define RECEIVE_EN 0#define TRANSFER_EN 1#define MAX_RXBUF 0x20extern unsigned char emissivity;extern unsigned char tx_count,txbuf[15];extern unsigned char rx_count,rxbuf[15];extern unsigned char tx_number,rx_number;extern bit MODBUS_T35,rx_ok;unsigned char rx_temp;void InitTimer1() //针对标准8051{TMOD=(TMOD|0xf0)&0x1f; //将T1设为16位定时器TF1=0;TH1=0x62; //设T1位3.5位的接收时间35bit/9600bit/s=3.646msTL1=0x80;//晶振为11.0592MHz，T＝65535-3.646ms*11.0592MHz/12＝0x6280 ET1=1; //允许T1中断TR1=1; //T1开始计数}void timer1() interrupt 3 using 2 //定时器中断{TH1=0x62; //3.646ms interruptTL1=0x80;MODBUS_T35=ENABLE;if(rx_count>=5) //超时后，若接收缓冲区有数则判断为收到一帧{rx_ok=TRUE;}}void scomm() interrupt 4 using 3 //modbus RTU模式{if(TI){TI = 0;if(tx_count < tx_number) //是否发送结束{SBUF = txbuf[tx_count];}tx_count++;}if(RI){rx_temp=SBUF;if(rx_ok==FAULT) //已接收到一帧数据，在未处理之前收到的数舍弃{if(rx_countrxbuf[rx_count]=rx_temp;rx_count++;}TH1=0x62; //timer1 reset,count againTL1=0x80;RI=0;}}在主循环中判断标志rx_ok来执行帧处理。

51单片机新手入门之Modbus通讯本文和另一篇----C# WPF新手入门之Modbus通讯为一个系列，所用模块均是气体分析模块，之前用C3做的上位机（主要是方便调试，单片机不好搞），既然电脑上串口通讯代码没问题，那么放到单片机稍加修改也就理所当然肯定可行O(∩_∩)O~。

本文包括单片机的电路设计和软件设计两部分（单片机采用STC12C5A60S2双串口），至此单片机和上位机的串口通讯均成功实现，供需要的同学参考。

1.电路设计Altium Designer原理图如下：电源部分：24V转5V及6VAD及滤波Modbus通讯电脑串口通讯lcd屏显示预留接口，可以另接MAX232用来调试发送给模块数据正确性实际效果如下：电脑串口接收到的数据，和LCD 屏显示的是一样的下载步骤1. 选择芯片下载步骤2. 打开串口 下载步骤3. 打开hex 文件 下载步骤4. MCU 先断电，点击下载，看到提示后上电2.软件设计这里最麻烦的在于模块的Modbus通讯需要偶校验，我是手动添加的校验位，例如字符‘0’换成ASCII码0X30，添加偶校验后就是0X3A，把所有需要发送的数据一个个手动添加了再发送^_^；另外lcd12864屏也搞半天，主要照着时序图写必须sid先发送，然后sclk，不然不行￣□￣。

气体模块详细的通讯协议参考和上位机通讯那篇，此处不再介绍。

图中电路板没有焊AD芯片和温度芯片，引脚备用，相关代码注释掉了。

代码如下：#include "STC12C5A60S2.H"#include <intrins.H>.//头文件#define uchar unsigned char#define uint unsigned intuchar sendbuffer[17];//发送数据uchar flag=0;uchar re_buffer[32];uchar count=0;uint ad_data=0;double ad_vol=0;uint con_mid=0;uint gascon=0;long sum_o2=0;uint average_counter=20;uint idata oldtemp[21];uchar idata Send_Buff[20]; //moduleuint pre_contemp=0;uint O2_con=0;uchar idata test[21]; //moduleuint temperature=0;uint dat;uint testlcd=0;uchar c[]={0xb0,0xb1,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7,0xb8,0xb9};//MAX1241 模数芯片引脚设置，此电路板我没焊^_^//sbit ADC_CS=P0^1;//sbit ADC_CLK=P0^0;//sbit ADC_DOUT=P0^2;sbit ADC_CS=P3^6;sbit ADC_CLK=P3^5;sbit ADC_DOUT=P3^7;//LCD12864 LCD屏幕引脚设置sbit cs=P2^2;sbit sid=P2^1;sbit sclk=P2^0;sbit DQ=P0^1; //DS18B20 温度引脚设置，依然没有…#define N 11#define N2 20void delayms(unsigned char t){unsigned char i;unsigned char j;for(j=t;j;j--)for(i=192;i;i--);/*1ms延时*/}void delayus(uint t){uint i;for(i=0;i<t;i++){_nop_();}}void delay(float sec){unsigned int i;unsigned int j;j=sec*100;while(j--){i=1561;while(--i);}}void UART1_init() //串口1初始化，此串口和电脑通讯{TMOD=0x20;/设置定时器工作方式2TH1=0xfd; //波特率9600TL1=0xfd;TR1=1;REN=1;SM0=0;SM1=1;//ES=1;}void UART2_init()//串口2初始化，和模块通讯 Modbus{S2CON= 0x50; //方式1，允许接收BRT = 0xf4; //波特率2400AUXR = AUXR |0X10; //允许独立波特率允许AUXR1 = AUXR1&0xef; //将uart2切换到P1口IE2 = IE2|0X01; //允许串口2中断}void UART1_Send (unsigned char UART_data)//{//ES=0;SBUF = UART_data; //将接收的数据发送回去while(TI!=1); //检查发送中断标志位TI = 0; //另发送中断标志位为0//ES=1;}void UART2_Send(unsigned char UART_data)//串口2发送{//ES = 0 ;S2BUF = UART_data;while((S2CON&0x02)!=0x02);S2CON &= ~0x02;//ES = 1 ;}void UART1_Send_String (char *str, char len)//串口1发送字符串{unsigned char i;for(i=0;i<=len;i++){UART1_Send(str[i]);}}void UART2_Send_String (char *str, char len) //串口2发送字符串{unsigned char i;for(i=0;i<=len;i++){UART2_Send(str[i]);}}unsigned char Creat_Addr(unsigned char adr, unsigned char position)//计算模块地址{unsigned char hich;unsigned char loch;hich = adr/16;loch = adr%16;if(hich>9)hich+=7;if(loch>9)loch+=7;if(position == 1){return hich+0x30;}else if(position == 0){return loch+0x30;}}unsigned char CheckSum(unsigned char *str, unsigned char position, uchar len)/计算校验码{uchar i;unsigned int sum=0;uchar hi, lo;//uchar len = 12;for(i = 1; i <= len; i ++){*str ++;sum += *str;}sum = 256-(sum%256);hi = sum/16;lo = sum%16;if(hi > 9)hi += 7;if(lo > 9)lo += 7;hi += 0x30;lo += 0x30;if(sum == 256)hi = lo = 0x30;if(position == 1){return hi;}else if(position == 0){return lo;}}void data_init(){sendbuffer[0]=0x5B;sendbuffer[1]=0x30;sendbuffer[2]=0x30;sendbuffer[3]=0x30;sendbuffer[4]=0x30;sendbuffer[5]=0x30;sendbuffer[6]=0x7C;sendbuffer[7]=0x30;sendbuffer[8]=0x30;sendbuffer[9]=0x30;sendbuffer[10]=0x30;sendbuffer[11]=0x30;//TEMsendbuffer[12]=0x30;sendbuffer[13]=0x30;sendbuffer[14]=0x5D;sendbuffer[15]=0x0D;sendbuffer[16]=0x0A;}void calculate_module(unsigned char str[])//lcd屏显示{unsigned int concen;uchar wan,qian,bai,shi,ge;/*uchar d4 = str[7]-48;uchar d3 = str[8]-48;uchar d2 = str[9]-48;uchar d1 = str[10]-48;*/ //浓度只需要后面部分 uchar d4 = str[24]-48;uchar d3 = str[25]-48;uchar d2 = str[26]-48;uchar d1 = str[27]-48;if(d4>9)d4-=7;if(d3>9)d3-=7;if(d2>9)d2-=7;if(d1>9)d1-=7;concen = d4*4096+d3*256+d2*16+d1;gascon=concen;wan=concen/10000;qian=concen%10000/1000;bai=concen%1000/100;shi=concen%100/10;ge=concen%10;//sendbuffer[6]=wan+0x30; //最终显示XXX.X%sendbuffer[7]=qian+0x30;sendbuffer[8]=bai+0x30;sendbuffer[9]=shi+0x30;sendbuffer[10]=ge+0x30;}void module_init()//气体模块初始化{Send_Buff[0] = ':';Send_Buff[3] = '0';Send_Buff[4] = '3';Send_Buff[5] = '0';Send_Buff[6] = '0';Send_Buff[7] = '0';Send_Buff[8] = 'A';Send_Buff[9] = '0';Send_Buff[10] = '0';Send_Buff[11] = '0';Send_Buff[12] = '1';Send_Buff[1] = Creat_Addr(31, 1);Send_Buff[2] = Creat_Addr(31, 0);Send_Buff[13] = CheckSum(Send_Buff, 1, 12);Send_Buff[14] = CheckSum(Send_Buff, 0, 12);Send_Buff[15] = 0x0D;Send_Buff[16] = 0x0A;//手动添加校验，例如字符‘0’换成ASCII码0X30，添加偶校验后就是0X3A，最终发送给模块的以下数据，地址被写死，这个不像C#做的一目了然O(∩_∩)Otest[0]=0X3A;test[1]=0XB1;test[2]=0XC6;test[3]=0X30;test[4]=0X33;test[5]=0X30;test[6]=0X30;test[7]=0X30;test[8]=0X41;test[9]=0X30;test[10]=0X30;test[11]=0X30;test[12]=0XB1;test[13]=0X39;test[14]=0XB4;test[15]=0X8D;test[16]=0X0A;}/*uint read_max1241() AD芯片处理{uint ADC_Data;uchar i;ADC_CLK=0;ADC_CS=0;ADC_Data=0;while(!ADC_DOUT);ADC_CLK=1;ADC_CLK=0;for(i=0;i<12;i++){ADC_CLK=1;ADC_Data<<=1;ADC_Data |= ADC_DOUT;ADC_CLK=0;}ADC_CS=1;ADC_CLK=0;return ADC_Data;}unsigned int ad_filter()//滤波{unsigned int count1,i,j;unsigned int value_buf[N];unsigned int temp;unsigned int sum=0;for (count1=0;count1<N;count1++){value_buf[count1] =read_max1241(); delayms(20);}for (j=0;j<(N-1);j++){for (i=0;i<(N-j);i++){if ( value_buf[i]>value_buf[i+1] ) {temp = value_buf[i];value_buf[i] = value_buf[i+1]; value_buf[i+1] = temp;}}}for(count1=3;count1<(N-3);count1++){sum += value_buf[count1];}return (unsigned int)(sum/(N-6));}void calculate_o2()//测试用{uchar wan,qian,bai,shi,ge;uint con_fin=0;uchar i;ad_data=ad_filter();ad_vol=(ad_data/4096.0)*2500.0;//Voltage ad_data=(uint)ad_vol; //concentrationdelayms(2);if(average_counter>0){sum_o2+= ad_data;oldtemp[average_counter-1]=ad_data;average_counter--;}else{sum_o2 -=oldtemp[19];for(i=20;i>0;i--){oldtemp[i]=oldtemp[i-1];}oldtemp[0]=ad_data;sum_o2+=oldtemp[0];con_fin=(uint)(sum_o2/N2);//O2_con=0.8*con_fin+0.2*pre_contemp;//pre_contemp=O2_con;wan=con_fin/10000;qian=con_fin%10000/1000;bai=con_fin%1000/100;shi=con_fin%100/10;ge=con_fin%10;sendbuffer[1]=wan+0x30;sendbuffer[2]=qian+0x30;sendbuffer[3]=bai+0x30;sendbuffer[4]=shi+0x30;sendbuffer[5]=ge+0x30;delayms(5);}}//-------------18B20 温度显示复位函数--------------- void ow_reset(void){char presence=1;while(presence){while(presence){DQ=1;delayus(2);DQ=0; //delayus(550); // 550usDQ=1; //delayus(66); // 66uspresence=DQ;}delayus(500); //延时500uspresence = ~DQ;}DQ=1;}//-----------18B20写命令函数------------void write_byte(uchar val){uchar i;for (i=8; i>0; i--) //{DQ=1;delayus(2);DQ = 0;delayus(5);//5usDQ = val&0x01;delayus(66); //66usval=val/2;}DQ = 1;delayus(11);}//--------------18B20读一个字节函数---------uchar read_byte(void){uchar i;uchar value = 0;for (i=8;i>0;i--){DQ=1;delayus(2);value>>=1;DQ = 0;delayus(4); //4usDQ = 1;delayus(4); //4usif(DQ)value|=0x80;delayus(66); //66us}DQ=1;return(value);}void Read_Temperature(void){unsigned int Temp1,Temp2;uchar bai,shi,ge;ow_reset(); //DS18B20write_byte(0xCC);write_byte(0x44);ow_reset(); //DS1302复位write_byte(0xCC);write_byte(0xbe);Temp1=read_byte();Temp2=read_byte();ow_reset();temperature=(((Temp2<<8)|Temp1)*0.625); //0.0625=xx, 0.625=xx.x, 6.25=xx.xxbai=temperature/100;shi=temperature%100/10;ge=temperature%10;sendbuffer[11]=bai+0x30;sendbuffer[12]=shi+0x30;sendbuffer[13]=ge+0x30;delayms(5);}* //图中电路板此部分没焊，此部分代码不使用^_^void writecmd_lcd(uchar cmd) //lcd屏写指令{uchar i;uchar cmd1;cmd1=cmd;//----------先写控制，选择写指令，还是写数据11111000 for(i=0;i<5;i++) //必须sid先发送，然后sclk，不然不行 {sid=1;sclk=1;sclk=0;}for(i=0;i<3;i++){sid=0;sclk=1;sclk=0;}//delayms(10);cmd=cmd&0xf0; //先高4位for(i=0;i<8;i++){if(cmd&0x80){sid=1;}else sid=0;sclk=1;sclk=0;cmd=cmd<<1;}//delayms(10);cmd1=((cmd1<<4)&0xf0); //低4位 for(i=0;i<8;i++){if(cmd1&0x80){sid=1;}else sid=0;sclk=1;sclk=0;cmd1=cmd1<<1;}}void writedata_lcd(uchar dat) {uchar i;uchar dat1;dat1=dat;//11111010for(i=0;i<5;i++){sid=1;sclk=1;sclk=0;}sid=0;sclk=1;sclk=0;sid=1;sclk=1;sclk=0;sid=0;sclk=1;sclk=0;//delayms(10);dat=dat&0xf0;for(i=0;i<8;i++)if(dat&0x80){sid=1;}else sid=0;sclk=1;sclk=0;dat=dat<<1;}//delayms(10);dat1=((dat1<<4)&0xf0);for(i=0;i<8;i++){if(dat1&0x80){sid=1;}else sid=0;sclk=1;sclk=0;dat1=dat1<<1;}}void init_lcd()//初始化lcd屏{cs=1;writecmd_lcd(0x30);//设定为8位控制writecmd_lcd(0x0c);//显示打开writecmd_lcd(0x01);//清屏}void gotoxy(uint row, uint col){switch(row){case 1: writecmd_lcd(0x80+col);break; case 2: writecmd_lcd(0x90+col);break; case 3: writecmd_lcd(0x88+col);break; case 4: writecmd_lcd(0x98+col);break;}void clear(){writecmd_lcd(0x01);delayms(10);}void SendStr(uchar *str){uchar i;for(i=0;str[i]!='\0';i++){writedata_lcd(str[i]);}}void lcd_display(uint lcddata)//lcd屏显示浓度{uchar wan,qian,bai,shi,ge;wan=lcddata/10000;qian=lcddata%10000/1000;bai=lcddata%1000/100;shi=lcddata%100/10;ge=lcddata%10;gotoxy(2,1);writedata_lcd(0xa3);writedata_lcd(c[qian]);gotoxy(2,2);writedata_lcd(0xa3);writedata_lcd(c[bai]);gotoxy(2,3);writedata_lcd(0xa3);writedata_lcd(c[shi]);gotoxy(2,4);SendStr(".");gotoxy(2,5);writedata_lcd(0xa3);writedata_lcd(c[ge]);gotoxy(2,6);SendStr("%");}void main()//主函数{delay(2.1);UART1_init();UART2_init();data_init();module_init();init_lcd();EA=1;delay(2.1);while(1){/*calculate_o2();//测试用Read_Temperature();*/ //温度芯片没焊UART2_Send_String(test,16);//串口2：和模块通讯delay(0.8);if(flag==1){calculate_module(re_buffer);delayms(5);UART1_Send_String(sendbuffer,16);//串口1：电脑上可以接收发送的数据 flag=0;delay(0.8);}lcd_display(gascon);//lcd显示浓度delay(0.8);}}/*void uart1_in() interrupt 4/串口1中断，不使用，因为只是发送{RI=0;re_buffer[count]=SBUF;if(re_buffer[0]!=':'){count=0;}else{count++;if(count==10){flag=1;count=0;}}}*/void uart2_in() interrupt 8//串口2中断，需要接受模块返回的数据{if(S2CON&0X01){re_buffer[count]=S2BUF;re_buffer[count]&=0x7f;count++;S2CON&=0XFE;}if(count==32){count=0;flag=1;}}。

#include <REGX52.H>#include<intrins.h>//_nop_();#define OSFREQ 11059200char TimeInterval;char MyAddress;char data DI[6]={1,2,3,4,5,6};char data DO[6]={6,7,8,9,10,11};char data AI[6]={11,12,13,14,15,16};char data AO[6]={16,17,18,19,20,21};unsigned char data ReceiveData[14];unsigned char data countnumber;sbit Recenable =P1^6;//控制端sbit led =P2^7;//控制端/*---------------------------------------------------------------------------函数说明：CRC 高位字节值表---------------------------------------------------------------------------*/ static unsigned char code auchCRCHi[] = {0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40} ;/*---------------------------------------------------------------------------函数说明：CRC低位字节值表---------------------------------------------------------------------------*/ static unsigned char code auchCRCLo[] = {0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,0x43, 0x83, 0x41, 0x81, 0x80, 0x40};/*---------------------------------------------------------------------------调用方式：unsigned int CRC16(unsigned char *puchMsg, unsigned int usDataLen) 函数说明：CRC校验---------------------------------------------------------------------------*/unsigned int CRC16(unsigned char *puchMsg, unsigned int usDataLen){unsigned char uchCRCHi = 0xFF ; // 高CRC字节初始化unsigned char uchCRCLo = 0xFF ; // 低CRC 字节初始化unsigned uIndex ; // CRC循环中的索引while (usDataLen--) // 传输消息缓冲区{uIndex = uchCRCHi ^ *puchMsg++ ; // 计算CRCuchCRCHi = uchCRCLo ^ auchCRCHi[uIndex] ;uchCRCLo = auchCRCLo[uIndex] ;}return (uchCRCHi << 8 | uchCRCLo) ;}/*---------------------------------------------------------------------------调用方式：unsigned char getbit(unsigned int address,unsigned char function)函数说明：取出所给地址的位值---------------------------------------------------------------------------*/unsigned char getbit(unsigned int address,unsigned char function){unsigned char data Offset;unsigned char data temp;unsigned char data *Myaddress;Offset=(char)address&0x07;switch (function) //根据功能码不同进行相应处理{case 2:Myaddress=DI;break;case 1:Myaddress=DO;break;default:return 2;}temp=(char)(address>>3);temp=*(Myaddress+temp);temp>>=(Offset);if (temp&0x01)return 1;elsereturn 0;}/*---------------------------------------------------------------------------调用方式：void SendData(unsigned char *output,unsigned char Outlength) 函数说明：发送数据至窗口---------------------------------------------------------------------------*/void SendData(unsigned char *output,unsigned char Outlength){ES=0;while(Outlength--){TI=0;ACC=*output;TB8=P;SBUF=*(output++);while(!TI);TI=0;}ES=1;}/*---------------------------------------------------------------------------调用方式：void Function12(unsigned char address,unsigned char len)函数说明：功能码1，2处理---------------------------------------------------------------------------*/void Function12(unsigned char address,unsigned char len){unsigned int data i;unsigned char data j;unsigned char data length;unsigned char data *send;unsigned int data temp;unsigned char data function;length=0;send=ReceiveData;function=send[1];for (i=1;i<=len;i++){length++;*(send+2+length)=0;for (j=0;j<8;j++){*(send+2+length)=*(send+2+length)|getbit(address,function)<<j; address++;i++;if(i>len)break;}i--;}*(send+2)=length; //数据长度temp=CRC16(send,length+3); //DI状态数据*(send+3+length)=(char)(temp>>8); //CRC校验高*(send+4+length)=(char)temp; //CRC校验低SendData(send,length+5); //调用A发送程序}/*---------------------------------------------------------------------------调用方式：void Function3(unsigned char address,unsigned char len) 函数说明：功能码3处理-----读取寄存器---------------------------------------------------------------------------*/void Function3(unsigned char address,unsigned char len){unsigned char data i;unsigned char data *send;unsigned int data temp;send=ReceiveData;*(send+2)=2*len; //数据长度高address=2*address;for(i=0;i<len;i++) //取输入寄存器数据{*(send+3+2*i)=AO[address++];*(send+4+2*i)=AO[address++];}temp=CRC16(send,2*len+3); //CRC校验*(send+3+2*len)=(char)(temp>>8);*(send+4+2*len)=(char)temp;SendData(send,2*len+5); //调用A发送程序}/*---------------------------------------------------------------------------调用方式：void Function4(unsigned char address,unsigned char len) 函数说明：功能码处理4----读取输入寄存器---------------------------------------------------------------------------*/void Function4(unsigned char address,unsigned char len){unsigned char data i;unsigned char data *send;unsigned int data temp;send=ReceiveData;*(send+2)=2*len;address=2*address;for(i=0;i<len;i++) //取数据{*(send+4+2*i)=AI[address++];*(send+3+2*i)=AI[address++];}temp=CRC16(send,2*len+3);*(send+3+2*len)=(char)(temp>>8);*(send+4+2*len)=(char)temp;SendData(send,2*len+5);}/*---------------------------------------------------------------------------调用方式：void Function6(unsigned char address)函数说明：写单路寄存器---------------------------------------------------------------------------*/void Function6(unsigned char address){int temp;unsigned char data *WriteData;temp=2*address;WriteData=AO;//将写入的数据进行处理//your code to add here to deal with the write value*(WriteData+temp)=ReceiveData[4];*(WriteData+temp+1)=ReceiveData[5];SendData(ReceiveData,countnumber); //调用发送程序，返回与主机相同的报文}/*---------------------------------------------------------------------------调用方式：void SendError(char ErrorCode)函数说明：---------------------------------------------------------------------------*/void SendError(char ErrorCode){unsigned char data *send;unsigned int data temp;send=ReceiveData;*(send+1)=ReceiveData[1]|0x01;//最高位置1*(send+2)=ErrorCode;temp=CRC16(send,3);*(send+3)=(char)(temp>>8);*(send+4)=(char)temp;SendData(send,countnumber); //调用发送程序,返回错误代码}/*---------------------------------------------------------------------------调用方式：void Deal()函数说明：接收数据处理---------------------------------------------------------------------------*/void Deal(){unsigned int data temp;unsigned char data address;unsigned char data length;unsigned char data counter;unsigned char data *Pointer;Pointer=ReceiveData;counter=countnumber;if (counter<=3 ) return;temp=Pointer[counter-2]<<8;temp= temp|Pointer[counter-1];if( temp==CRC16(Pointer,counter-2)) //较验正确{address=Pointer[3];length=Pointer[5];if(address<48){switch (Pointer[1]) //根据功能码不同进行相应处理*/{case 1:Function12(address,length);break;case 2:Function12(address,length);break;case 3:address=address-1;Function3(address,length);break;case 4:address=address-1;Function4(address,length);break;case 6:address=address-1;Function6(address);default:SendError(0x81);break;}}else{ SendError(0x82);}}countnumber=0;}/*bit Chargetbit(unsigned char character,unsigned char Number){if(character>>Number&0x01==1)return 1;elsereturn 0;}//设定某一位的值*********************************************************** unsigned char SetBit(unsigned char Character,unsigned char num,bit boolen){unsigned char code bit_value[]={1,2,4,8,16,32,64,128};if(boolen)return Character|bit_value[num];elsereturn Character&~bit_value[num];}*//*---------------------------------------------------------------------------调用方式：void Init_timer2(unsigned int baudrate)函数说明：定时器2的初始化---------------------------------------------------------------------------*/void Init_timer2(unsigned int baudrate){unsigned int data TimReg2;T2CON = 0x00;T2MOD = 0x00;TimReg2=65536-(OSFREQ/384/baudrate*11);RCAP2L=TimReg2&0x00ff;RCAP2H=(TimReg2>8); //RCAP2H=TimReg2/256RCAP2L=0;RCAP2H=0;TL2 = RCAP2L; //TH2 = RCAP2H; //TR2=1; // T2CON.2 start timerET2=0; // 开定时器2中断}/*---------------------------------------------------------------------------调用方式：void Init_SerialPort(unsigned int baudrate)函数说明：串口初始化---------------------------------------------------------------------------*/void Init_SerialPort(unsigned int baudrate){unsigned char TimReg2;SCON = 0xd0; // 方式3, 8-bit UART, enable rcvrTMOD = 0x21; // T0方式1（16位）, T1方式2,8位重装TimReg2=256-(OSFREQ/384/baudrate);TH1 = TimReg2; // 定时器1,在11.0592MHz下,波特率为9600 TL1 = TH1;TR1= 1; // TR1: 定时开始//PS=1; // 串行中断优先ES=1; // 接收中断}/*---------------------------------------------------------------------------函数说明：主函数---------------------------------------------------------------------------*/main(){EA=1; //开总中断Init_SerialPort(9600);Init_timer2(9600);Recenable=0; //接收允许MyAddress=0x01; //本机地址while(1){}}/*---------------------------------------------------------------------------调用方式：void SeiralA() interrupt 4 using 0函数说明：通讯中断---------------------------------------------------------------------------*/void SeiralA() interrupt 4 using 0{if(RI){if((TimeInterval>2)&&(TimeInterval<=4)){ countnumber=0;}if(countnumber>60){ countnumber=0;}ReceiveData[countnumber++]=SBUF; //将接收到的数据到缓冲区内TimeInterval=0;RI=0;ET2=1; //当接收到数据后,将定时器2开启}}/*---------------------------------------------------------------------------调用方式：void SerialPortTime() interrupt 5 using 0函数说明：定时器2中断程序---------------------------------------------------------------------------*/void SerialPortTime() interrupt 5 using 0{ET2=0; //定时器2中断允许控制TimeInterval=TimeInterval+1;if((TimeInterval>4) && countnumber){Recenable=1; //发送Deal(); //将接收到的数据进行处理Recenable=0; //接收countnumber=0;}else{ ET2=1;} //将定时器2打开TF2=0; //定时器2溢出标志,软件清0}。

modbus通信1、LCD.c#include <reg51.h>#include<LCD.h>unsigned char code number_X[]={ //宽x高=8x16,纵向字节倒序0x00,0xE0,0x10,0x08,0x08,0x10,0xE0,0x00, //00x00,0x0F,0x10,0x20,0x20,0x10,0x0F,0x00,0x00,0x10,0x10,0xF8,0x00,0x00,0x00,0x00, //10x00,0x20,0x20,0x3F,0x20,0x20,0x00,0x00,0x00,0x70,0x08,0x08,0x08,0x88,0x70,0x00, //20x00,0x30,0x28,0x24,0x22,0x21,0x30,0x00,0x00,0x30,0x08,0x88,0x88,0x48,0x30,0x00, //30x00,0x18,0x20,0x20,0x20,0x11,0x0E,0x00,0x00,0x00,0xC0,0x20,0x10,0xF8,0x00,0x00, //40x00,0x07,0x04,0x24,0x24,0x3F,0x24,0x00,0x00,0xF8,0x08,0x88,0x88,0x08,0x08,0x00, //50x00,0x19,0x21,0x20,0x20,0x11,0x0E,0x00,0x00,0xE0,0x10,0x88,0x88,0x18,0x00,0x00, //60x00,0x0F,0x11,0x20,0x20,0x11,0x0E,0x00,0x00,0x38,0x08,0x08,0xC8,0x38,0x08,0x00, //70x00,0x00,0x00,0x3F,0x00,0x00,0x00,0x00,0x00,0x70,0x88,0x08,0x08,0x88,0x70,0x00, //80x00,0x1C,0x22,0x21,0x21,0x22,0x1C,0x00,0x00,0xE0,0x10,0x08,0x08,0x10,0xE0,0x00, //90x00,0x00,0x31,0x22,0x22,0x11,0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, // .0x00,0x00,0x00,0x00,0x00,0x60,0x60,0x00,0x00,0x80,0x80,0x80,0x80,0x80,0x80,0x00, //-0x00,0x01,0x01,0x01,0x01,0x01,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, //nop 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0xC0,0x00,0x00,0x00, //：0x00,0x00,0x00,0x30,0x30,0x00,0x00,0x00};void LCD_WriteCommandE1(unsigned char com) {while(CRADD1 & 0x80);CWADD1 = com;}void LCD_WriteDataE1(unsigned char dat)while(CRADD1 & 0x80);DWADD1 = dat;}void LCD_WriteCommandE2(unsigned char com) {while(CRADD2 & 0x80);CWADD2 = com;}void LCD_WriteDataE2(unsigned char dat){while(CRADD2 & 0x80);DWADD2 = dat;}void LCD_Init(){LCD_WriteCommandE1(0xe2);LCD_WriteCommandE2(0xe2);LCD_WriteCommandE1(0xa4);LCD_WriteCommandE2(0xa4);LCD_WriteCommandE1(0xa9);LCD_WriteCommandE2(0xa9);LCD_WriteCommandE1(0xa0);LCD_WriteCommandE2(0xa0);LCD_WriteCommandE1(0xc0);LCD_WriteCommandE2(0xc0);LCD_WriteCommandE1(0xaf);LCD_WriteCommandE2(0xaf);}void LCD_Clear(void){unsigned char i,j;for(i=0;i<4;i++){LCD_WriteCommandE1(i+0xb8);LCD_WriteCommandE2(i+0xb8);LCD_WriteCommandE1(0x00);LCD_WriteCommandE2(0x00);for(j=0;j<0x50;j++){LCD_WriteDataE1(0x00);LCD_WriteDataE2(0x00);}}void display_cn(unsigned char lin,unsigned int col,unsigned int len,unsigned char *p) {unsigned int seg,i,j;unsigned char a,L,n;switch(lin){case 0: n=0xba;break;case 1: n=0xb8;break;}for(i=0;i<len;i++){for(j=0;j<2;j++){L=col;LCD_WriteCommandE1(n+j);LCD_WriteCommandE2(n+j);for(seg=0;seg<16;seg++){if (L < 61){a = L;LCD_WriteCommandE1(a);LCD_WriteDataE1(*p++);}else{a = L-61;LCD_WriteCommandE2(a);LCD_WriteDataE2(*p++);}L++;}}col=col+16;}}void display_number(unsigned char lin,unsigned int col,unsigned char num){unsigned int seg,i,j;unsigned char a,L,n,k;switch(lin){case 0: n=0xba;break;case 1: n=0xb8;break;}k=num*16;for(j=0;j<2;j++){L=col;LCD_WriteCommandE1(n+j);LCD_WriteCommandE2(n+j);for(seg=0;seg<8;seg++){if (L < 61){a = L;LCD_WriteCommandE1(a);LCD_WriteDataE1(number_X[k++]);}else{a = L-61;LCD_WriteCommandE2(a);LCD_WriteDataE2(number_X[k++]);}L++;}}}void display_unsigned_int(unsigned char lin,unsigned int col,unsigned int dat) {unsigned int seg;unsigned char k[4];k[3]=dat%10;k[2]=((dat/10)%10);k[1]=((dat/100)%10);k[0]=((dat/1000)%10);if(k[0]==0) {k[0]=12;}if((k[0]==12)&&(k[1]==0)){ k[0]=12;k[1]=12;}if((k[0]==12)&&(k[1]==12)&&(k[2]==0)){k[0]=12;k[1]=12;k[2]=12;}for(seg=0;seg<4;seg++){display_number(lin,col,k[seg]);col=col+10;}}void display_signed_int(unsigned char lin,unsigned int col,signed int dat){unsigned int seg;unsigned char k[5],a;k[0]=12;if(dat<0){dat=(~dat)+1;k[0]=11;}k[4]=dat%10;k[3]=((dat/10)%10);k[2]=((dat/100)%10);k[1]=((dat/1000)%10);a=k[0];if(k[1]==0) {k[0]=12;k[1]=a;}if((k[1]==a)&&(k[2]==0)){ k[0]=12;k[1]=12;k[2]=a;}if((k[1]==12)&&(k[2]==a)&&(k[3]==0)){k[0]=12;k[1]=12;k[2]=12;k[3]=a;}for(seg=0;seg<5;seg++){display_number(lin,col,k[seg]);col=col+10;}}void display_unsigned_char(unsigned char lin,unsigned int col,unsigned char dat) {unsigned int seg;unsigned char k[3];k[1]=dat%10;k[0]=((dat/10)%10);for(seg=0;seg<2;seg++){display_number(lin,col,k[seg]);col=col+10;}}2、LCD.h#include <reg51.h>#include <absacc.h>#ifndef __LCD__#define __LCD__#define CWADD1 XBYTE[0x8000]#define DWADD1 XBYTE[0x8001]#define CRADD1 XBYTE[0x8002]#define DRADD1 XBYTE[0x8003]#define CWADD2 XBYTE[0x8004]#define DWADD2 XBYTE[0x8005]#define CRADD2 XBYTE[0x8006]#define DRADD2 XBYTE[0x8007]extern void LCD_Init();extern void display_cn(unsigned char lin,unsigned int col,unsigned int len,unsigned char *p);extern void display_signed_int(unsigned char lin,unsigned int col,signed int dat);extern void display_unsigned_int(unsigned char lin,unsigned int col,unsigned int dat);extern void display_unsigned_char(unsigned char lin,unsigned int col,unsigned char dat);extern void LCD_Clear(void);#endif1、MCU.c#include <reg51.h>#include "MCU.h"#define oscillator 12000000void timer0_init(void){TMOD|=0x01;//Timer0 is 16 bits timer, timer1 is Baud rate generatorTH0=0x97;TL0=0xd5;TR0=1;ET0=1;}void uart_init(unsigned int baud_rate){PCON=0x00;SCON=0x50;TMOD|=0x20;TL1=256-(oscillator/384)/baud_rate;TH1=256-(oscillator/384)/baud_rate;TR1=1;ES=1;}2、MCU.h#ifndef __MCU__#define __MCU__extern void timer0_init(void);extern void uart_init(unsigned int baud_rate);#endif3、MODBUSASC.c#include <reg51.h>unsigned char xdata TX_buf[200]_at_ 0x9100;unsigned char xdata Dat[200] _at_ 0x9200;void Data_ASCII(unsigned char num,unsigned char * buf ){unsigned char a;a=(num>>4)&0x0f;if(a>9) buf[0]=a+0x37;else buf[0]=a+0x30;a=num&0x0f;if(a>9) buf[1]=a+0x37;else buf[1]=a+0x30;}unsigned char ASCII_Data(unsigned char* buf ){unsigned char a,b;a=buf[0]-0x30;if(a>9) a=a-0x07;b=buf[1]-0x30;if(b>9) b=b-0x07;a=(a<<4)|b;return (a);}unsigned char LRC(unsigned char*Msg_buf,unsigned char MsgLen){unsigned char LRC_buf = 0,i ;for(i=0;i<MsgLen;i++){LRC_buf=Msg_buf[i]+LRC_buf;}i=~LRC_buf;LRC_buf=i+1;return LRC_buf ;}void Send_modbusASC_UART(unsigned char* SendData,unsigned char DataLen) {unsigned char buf[2];unsigned int i,j,k;j=1;TX_buf[0]=0x3a;for(i=0;i<DataLen;i++){Data_ASCII(SendData[i],buf );TX_buf[j]=buf[0];j++;TX_buf[j]=buf[1];j++;}TX_buf[j]=0x0d;j++;TX_buf[j]=0x0a;j++;for(i=0;i<j;i++){TI=0;SBUF=TX_buf[i];while(!TI);TI=0;for(k=0;k<30;k++);}}void Send_modbusASC_Err(unsigned char FunNum,unsigned char ErrNum,unsigned char ID) {unsigned char temp[4];temp[0]=ID;temp[1]=FunNum+0x80;temp[2]=ErrNum;temp[3]=LRC(temp,3);Send_modbusASC_UART(temp,4);}void FunctionASC_NO3(unsigned char* Msg_buf,unsigned int* AO_state,unsigned char ID) {unsigned char a,i,j,n,temp[2];unsigned int Fun_addr,Fun_num;j=1;for(i=0;i<7;i++){temp[0]=Msg_buf[j];j++;temp[1]=Msg_buf[j];j++;Dat[i]=ASCII_Data(temp );}a=LRC(Dat,6);if(a!=Dat[6]) return;Fun_addr=(Dat[2]<<8)|Dat[3];Fun_num=(Dat[4]<<8)|Dat[5];if((Fun_num==0)||(Fun_num>64)){Send_modbusASC_Err(1,3,ID);return;}if(Fun_addr>63){Send_modbusASC_Err(1,2,ID);return;}Dat[0]=ID;Dat[1]=3;Dat[2]=Fun_num*2;j=3;n=Fun_addr;for(i=0;i<Fun_num;i++){Dat[j]=(unsigned char)(AO_state[n]>>8);j++;Dat[j]=(unsigned char)AO_state[n];j++;n++;}Dat[j]=LRC(Dat,j);Send_modbusASC_UART(Dat,j+1);}void FunctionASC_NO6(unsigned char* Msg_buf,unsigned int* AO_state,unsigned char ID) {unsigned char a,i,j,temp[2];unsigned int Fun_addr,Fun_out;j=1;for(i=0;i<7;i++){temp[0]=Msg_buf[j];j++;temp[1]=Msg_buf[j];j++;Dat[i]=ASCII_Data(temp );}a=LRC(Dat,6);if(a!=Dat[6]) return;Fun_addr=(Dat[2]<<8)|Dat[3];Fun_out=(Dat[4]<<8)|Dat[5];if(Fun_out>0xff00){Send_modbusASC_Err(1,3,ID);return;}if(Fun_addr>64){Send_modbusASC_Err(1,2,ID);return;}AO_state[Fun_addr]=Fun_out;j=1;for(i=0;i<5;i++){Dat[j]=Msg_buf[j];j++;}Dat[j]=LRC(Dat,j);Send_modbusASC_UART(Msg_buf,j+1);}4、MODBUSASC.h#ifndef _MODBUSASC_#define _MODBUSASC_#ifdef __cplusplusextern "C"{#endifextern void Data_ASCII(unsigned char num,unsigned char * buf );extern unsigned char ASCII_Data(unsigned char* buf );extern void FunctionASC_NO3(unsigned char* Msg_buf,unsigned int* AO_state,unsigned char ID);extern void FunctionASC_NO4(unsigned char* Msg_buf,unsigned int* AI_state,unsigned char ID);extern void FunctionASC_NO6(unsigned char* Msg_buf,unsigned int* AO_state,unsigned char ID);#ifdef __cplusplus}#endif5、MAIN.c#include <reg51.h>#include<LCD.h>#include<main.h>#include "mcu.h"#include "modbusASC.h"void wait(unsigned int x){unsigned int i;i=0;for(i=0;i<x;i++);}void timer0_isr(void)interrupt 1{TH0=0x3c;TL0=0xb0;ms_count++;if(ms_count>=20){ms_count=0;LED=~LED;S_flag=1;}}void UART_isr(void)interrupt 4{unsigned char a;RI=0;a=SBUF;if(a==0x3a)UART_offset=0;if(a==0x0a)UART_message=1;RX_buf[UART_offset]=a;UART_offset++;}void display(void){unsigned char i,col;col=28;display_unsigned_int(0,col,modbus_buf[0]);display_unsigned_int(1,col,modbus_buf[1]); }void ModbusASC_Msg(unsigned char* modmus_buf){unsigned char temp[2];unsigned char a;temp[0]=modmus_buf[1];temp[1]=modmus_buf[2];a=ASCII_Data(temp );if(a!=Mode_ID) return;temp[0]=modmus_buf[3];temp[1]=modmus_buf[4];a=ASCII_Data(temp );switch(a){case 0x03:{FunctionASC_NO3(modmus_buf,modbus_buf,Mode_ID);break;}case 0x06:{FunctionASC_NO6(modmus_buf,modbus_buf,Mode_ID);break;}}}void main(void){unsigned char i;LCD_Init();LCD_Clear();display_cn(0,0,1,RD_dat);display_cn(1,0,1,TD_dat);modbus_buf[0]=18;modbus_buf[1]=28;timer0_init();uart_init(2400);EA=1;Mode_ID=1;while(1){display( );if(UART_message==1){ModbusASC_Msg(RX_buf);UART_message=0;}if(S_flag==1){modbus_buf[0]++;S_flag=0;}}}6、MAIN.h#include <reg51.h>#ifndef MAIN_H__#define MAIN_H__code unsigned char RD_dat[]={ //纵向字节倒序。

51单片机modbus协议程序#include ;#define uint8 unsigned char#define uint16 unsigned int#define FOSC 16000000uint16 BAUD=9600;uint16 TEMP_Alert=1000;//字地址 0 - 255 (只取低8位)//位地址 0 - 255 (只取低8位)uint16 TempRegister; //用于测试字址址16 uint8 localAddr = 0x01; //单片机控制板的地址uint8 sendCount; //发送字节个数uint8 receCount;//接收到的字节个数//uint8 sendPosi;//发送位置uint8 xdata receBuf[1];uint8 xdata sendBuf[1];void checkComm0Modbus(void);uint16 getRegisterVal(uint16 addr,uint16*tempData);uint16 setRegisterVal(uint16 addr,uint16 tempData); void switch_BAUD(uint16 value);/*****************************波特率调整函数********************************/////函数功能：调整串口通信波特率////串口工作在工作方式1，即8位波特率可变模式/************************************************ ****************************/void switch_BAUD(uint16 value){switch(value){case 0x0001: { BAUD=9600;break; }case 0x0002: { BAUD=14400;break; }case 0x0003: { BAUD=19200;break; }}TR1=0;//停止定时器1ES=0;//关闭串口中断TH1=TL1=-(FOSC/12/32/BAUD);//设置波特率TR1=1;//开启定时器1ES=1;//使能串口中断}/***************************CRC校验码生成函数********************************/////函数功能：生成CRC校验码////本代码中使用查表法，以提高运算速度/****************************************************************************/uint16 crc16(uint8 *puchMsg, uint16 usDataLen){uint8 uchCRCHi = 0xFF ; /* 高CRC字节初始化 */uint8 uchCRCLo = 0xFF ; /* 低CRC 字节初始化 */uint16 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 (uchCRCLo ;>; 8;sendBuf[i+4] = tempData & 0xff;}sendBuf[0] = localAddr;sendBuf[1] = 3; //function code : 03sendBuf[2] = byteCount;byteCount += 3;//加上前面的地址，功能码，地址共3+byteCount 个字节crcData = crc16(sendBuf,byteCount);sendBuf[byteCount] = crcData & 0xff;// CRC代码低位在前byteCount++;sendBuf[byteCount] = crcData >;>; 8 ;//高位在后sendCount = byteCount + 1;//例如byteCount=49，则sendBuf[]中实际上有49+1个元素待发Begin_send();}//void readRegisters(void)/********从机响应主机问询函数，function code : 16，设置多个寄存器值 *********/////函数功能：丛机根据串口接收到的数据包receBuf[]里面的内容，根据被强制寄存器////的起始地址，去设置相应寄存器的值，响应数据包同询问数据包////的内容相同，经过串口发送到主机。

关于51单片机上实现modbus协议你找一个MODBUS的协议详细资料好好看看，就是一种通讯约定，你按照它规定的格式通讯就可以了协议发送给询问方。

Modbus协议包括ASCII、RTU、TCP等，并没有规定物理层。

此协议定义了控制器能够认识和使用的消息结构，而不管它们是经过何种网络进行通信的。

标准的Modicon控制器使用RS232C实现串行的Modbus。

Modbus的ASCII、RTU协议规定了消息、数据的结构、命令和就答的方式，数据通讯采用Maser/Slave方式，Master端发出数据请求消息，Slave端接收到正确消息后就可以发送数据到Master端以响应请求；Master端也可以直接发消息修改Slave端的数据，实现双向读写。

Modbus协议需要对数据进行校验，串行协议中除有奇偶校验外，ASCII模式采用LRC校验，RTU模式采用16位CRC校验，但TCP模式没有额外规定校验，因为TCP协议是一个面向连接的可靠协议。

另外，Modbus采用主从方式定时收发数据，在实际使用中如果某Slave站点断开后（如故障或关机），Master端可以诊断出来，而当故障修复后，网络又可自动接通。

因此，Modbus协议的可靠性较好。

下面我来简单的给大家介绍一下，对于Modbus的ASCII、RTU和TCP协议来说，其中TCP和RTU协议非常类似，我们只要把RTU协议的两个字节的校验码去掉，然后在RTU协议的开始加上5个0和一个6并通过TCP/IP网络协议发送出去即可。

所以在这里我仅介绍一下Modbus的ASCII和RTU协议。

下表是ASCII协议和RTU协议进行的比较：协议开始标记结束标记校验传输效率程序处理ASCII :（冒号）CR,LF LRC 低直观，简单，易调试RTU 无无CRC 高不直观，稍复杂通过比较可以看到，ASCII协议和RTU协议相比拥有开始和结束标记，因此在进行程序处理时能更加方便，而且由于传输的都是可见的ASCII字符，所以进行调试时就更加的直观，另外它的LRC校验也比较容易。