MODBUS通讯协议及RS485介面的PIC单片机通讯程式

#include "16f873.h" #include "int16cxx.h" #define ENABLE 1 #define DISABLE 0 #define TRUE 1 #define FAULT 0 #define RECEIVE_EN 0 #define TRANSFER_EN 1 #pragma bit IO1 @ PORTB.5 #pragma bit IO2 @ PORTB.6 #pragma bit IO3 @ PORTB.7 #pragma bit C_EN @ PORTC.2 #pragma origin = 0x4 uns8 rc_temp,rxbuf[8],uchCRCHi,uchCRCLo,addr,txbuf[8],receive_count,dis_hz,dis_current; uns8 set_hz,set_run; uns16 dis_error,dis_running; bit receive_ok,transfer_ok,_8ms_count_ok; /* Table of CRC values for high-order byte */ const char 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 } ; /* Table of CRC values for low-order byte */ const char 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 } ; interrupt server(void) { uns8 temp8; int_save_registers // W, STATUS (and PCLATH) char sv_FSR=FSR; if(T0IF) { TMR0=100; //8ms interrupt PS2=1; //prescale value=1:256 PS1=1; //5000KHz/256=19.53125KHz,19.53125K/156=0.125KHz(8ms) PS0=1; _8ms_count_ok=ENABLE; T0IF=0; } if(INTF) { INTF=0; } if(TMR1IF) { TMR2IF=0; } if(RCIF) { rc_temp=RCREG; if(receive_ok==FAULT) { if(_8ms_count_ok) receive_count=0; if(receive_count<8) rxbuf[receive_count]=rc_temp; if(receive_count==7 && addr==rxbuf[0]) receive_ok=TRUE; receive_count++; } _8ms_count_ok=DISABLE; TMR0=100; //timer0 reset,count again RCIF=0; } if(SSPIF && SSPIE) { SSPIF=0; } FSR=sv_FSR; int_restore_registers } page1 uns16 crc16(uns8 *puchMsg,uns8 crc_count) { uns8 uindex; uns16 temp16; uchCRCHi=0xff; uchCRCLo=0xff; while(crc_count) { uindex=uchCRCHi ^ *puchMsg; puchMsg++; uchCRCHi=uchCRCLo ^ auchCRCHi[uindex]; uchCRCLo=auchCRCLo[uindex]; crc_count--; } temp16=(uns16)uchCRCHi << 8; temp16=temp16 | uchCRCLo; return temp16; } page0 void main(void) { uns8 i; uns16 temp16; TRISA=0b11111111; TRISB=0b00011111; //RB7(IO3) RB6(IO2) RB5(IO1)->output TRISC=0b10111011; //RC7(RX) RC6(TX) RC2(C_EN)->output IO1=0; IO2=0; IO3=0; addr=0x06; dis_hz=79; dis_current=80; dis_error=87; dis_running=85; //bit2->0=stop,1=run //bit14->0=FR,1=RR _8ms_count_ok=DISABLE; receive_ok=FAULT; transfer_ok=TRUE; receive_count=0; C_EN=RECEIVE_EN; BRGH=1; SYNC=0; SPEN=1; TXIE=0; RCIE=1; TX9=0; //8 data bit transfer SPBRG=64; // baud rate=20M/16(64+1)=19230 TXEN=1; CREN=1; //receive enable T0CS=0; //TIMER0 clock=Fosc/4=20MHz/4=5MHz TMR0=100; //256-156 PSA=0; //use prescaler PS2=1; //prescale value=1:256 PS1=1; //5000KHz/256=19.53125KHz,19.53125K/156=0.125KHz(8ms) PS0=1; T0IE=1; //TIMER0 enable PEIE=1; GIE=1; rxbuf[0]=0x11; rxbuf[1]=0x03; rxbuf[2]=0x00; rxbuf[3]=0x6b; rxbuf[4]=0x00; rxbuf[5]=0x03; rxbuf[6]=0x01; rxbuf[7]=0x02; i=0; while(1) { if(receive_ok==TRUE) { temp16=crc16(rxbuf,6); if(rxbuf[6]==temp16.high8 && rxbuf[7]==temp16.low8) { switch(rxbuf[1]) { case 0x03: txbuf[0]=rxbuf[0]; txbuf[1]=rxbuf[1]; txbuf[2]=2; //byte count txbuf[3]=0; //data high byte switch(rxbuf[3]) { case 0: txbuf[4]=set_hz; //set hz break; case 85: txbuf[4]=set_run; //set run break; case 78: //display Hz txbuf[4]=dis_hz; //data low byte break; case 79: //display current txbuf[4]=dis_current; //data low byte break; case 84: //display running state txbuf[3]=dis_running.high8; //data high byte txbuf[4]=dis_running.low8; //data low byte break; case 86: //display error code txbuf[3]=dis_error.high8; //data high byte txbuf[4]=dis_error.low8; //data low byte } temp16=crc16(txbuf,5); txbuf[5]=temp16.high8; txbuf[6]=temp16.low8; transfer_ok=FAULT; break; case 0x06: txbuf[0]=rxbuf[0]; txbuf[1]=rxbuf[1]; txbuf[2]=rxbuf[2]; txbuf[3]=rxbuf[3]; txbuf[4]=rxbuf[4]; txbuf[5]=rxbuf[5]; txbuf[6]=rxbuf[6]; txbuf[7]=rxbuf[7]; switch(rxbuf[3]) { case 0: //set Hz set_hz=rxbuf[5]; break; case 85: //set run set_run=rxbuf[5]; } transfer_ok=FAULT; } } receive_ok=FAULT; } if(TXIF && TRMT && transfer_ok==FAULT) { C_EN=TRANSFER_EN; TXREG=txbuf[i]; i++; if(i==7 && txbuf[1]==3) { transfer_ok=TRUE; i=0; } if(i==8 && txbuf[1]==6) { transfer_ok=TRUE; i=0; } } if(TRMT) C_EN=RECEIVE_EN; } }