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1、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。uintSwitch=0xbc95;开关状态ucharbdataCoil1=0xff,Coil2=0xbc;/16位线圈状态sbitCoil1_bit0=Coil1A0;sbitCoil1_bit1=Coil1Al；sbitCoil1_bit2=Coil1A2;sbitCoil1_bit3=Coil1A3;sbitCoil1_bit4=Coil1A4;sbitCoil1_bit5=Coil1A5;sbitCoil1_bit6
2、=Coil1A6;sbitCoil1_bit7=Coil1A7;sbitCoil2_bit8=Coil2A0;sbitCoil2_bit9=Coil2A1;sbitCoil2_bit10=Coil2A2;sbitCoil2_bit11=Coil2A3;sbitCoil2_bit12=Coil2A4;sbitCoil2_bit13=Coil2A5;sbitCoil2_bit14=Coil2A6;sbitCoil2_bit15=Coil2A7;uintidataReOnlybuf=0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b
3、,0x0c,0x0d,0x0e,0x0f;uintidataReWrbuf=0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f;/CRC校验查表码值constucharcodeauchCRCHi=0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC
4、0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC
5、0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC
6、0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC
7、0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40;constucharcodeauchCRCLo=0x00,0xC0,0xC1,0x01,0xC3,0x03,0x02,0xC2,0xC6
8、,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
9、,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
10、,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
11、,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
12、,0x42,0x43,0x83,0x41,0x81,0x80,0x40;ggFunction：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）uintcrccheck(uchar*puchMsg,ucharusDataLen)ucharuchCRCHi=0xFF;ucharuchCRCLo=0xFF;ucharuIndex;while(usDataLen-)ulndex=uchCRCHi八*puchMsg+;uchCRCHi=uchCRCLo八auchCRCHiuIndex;uchCRCLo=auchCRCLouIndex;return(uchCRCH
13、i8|uchCRCLo);agFunction：读线圈状态子函数Input:无Output：无voidReadCoil(void)uintStartAddress,tempAddress;ucharCoilNum,i,ByteNum,j;ucharCoilVal;bitexit=0;StartAddress=resvbuf2;StartAddress=StartAddress|resvbuf3;tempAddress=StartAddress;CoilNum二resvbuf5;读取的位数ByteNum=CoilNum/8;if(CoilNum%8!=0)ByteNum+;Sendbuf2=By
14、teNum;返回的字节数if(resvbuf1=0x01)for(i=0;iByteNum;i+)Sendbufi+3=0;for(j=0;j8;j+)CoilVal=GetCoilVal(StartAddress);Sendbufi+3|=CoilVal=tempAddress+CoilNum)exit=1;break;if(exit=1)break;elseif(resvbuf1=0x02)for(i=0;iByteNum;i+)Sendbufi+3=0;for(j=0;j8;j+)CoilVal=GetSWVal(StartAddress);Sendbufi+3|=CoilVal=tem
15、pAddress+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voidReadRegisters(void)uintStartAddress;ucharByteCount,i;StartAddress=resvbuf2;StartAddress=StartAddress8|resvbuf3;ByteCount=resvbuf5*2;Sendbuf2=resvbuf5;if(resvbuf1=0x03)for(i=0;i8;StartAddress+
