485通信.docx

1、485通信主机的关键部分：/*485多机通讯-通讯规则: 1:时钟7.3728 MHz/波特率9600/9个数据位/奇校验/1个停止位/硬件多机通讯功能/ 2:通讯连接采用硬件MAX485,双向单工 3:每个上行/下行的数据包的字节个数都是一样的(通讯数据量) 4:每个上行/下行的数据包都采用CRC8校验 5:数据接收采用中断+查询的方式 6:总是由主机向从机发送一个数据包,从机收到数据包后向主机回复一个数据包 7:不管是主机还是从机,如果收到的数据包有任何错误,都将丢弃该数据包,等效于没有接收 8:从机之间不能相互通讯,必须通过主机才能交换数据 9:无效地址是0,主机地址是1,从机地址是2.

2、3.4.广播地址是255 */ #include #include #include delay.h #include 1602.h #include usart.h #include crc8.h /CRC校验函数就在这个文件里面 #include key.h #define amount 10 /设定通讯数据量(包括1个地址帧,n个数据帧,1个校验帧) unsigned char sendamount; /发件箱 unsigned char inboxamount; /收件箱 unsigned char n=0; /记忆中断次数 unsigned char flag_me=0; /个人数据

3、标志unsigned char flag_all=0; /广播数据标志/-主机接收子程序- #pragma interrupt_handler RXC_Int: 12void RXC_Int(void) /接收中断 unsigned char ERROR=0; if(UCSRA&0x08|UCSRA&0x10 )ERROR=1; /奇偶效验错误(avr自动完成)或者帧错误就记录下来inboxn=UDR;n+; /记忆中断次数 if(ERROR) inbox0=0; /如果通讯有错,收件箱的地址帧就标记成无效地址0 void int_485(void) /接收程序,在中断中调用或者扫描调用/if

4、(n3) 如果接收到的数据还不到3个，那么就是通讯线路故障 /如果收件箱已经收到amount个数据,并且crc8校验成功就. if(n=amount & inboxamount-1=crc8(inbox,amount-1) if(inbox0=1)flag_me=1; /主机地址/接收完数据后会置标志位,在读取数据后要把标志位置零 if(inbox0=255) flag_me=1; /广播地址,接收后不要回复/接收完数据后会置标志位,在读取数据后要把标志位置零 void out_485(unsigned char address,unsigned char *ptr)unsigned char

5、 i;n=0; /中断次数清0 inbox0=0; /收件箱地址清0 /请更新准备发送的数据 /send1=? /. /sendn=? send0=address; /改变这个地址就可以实现与某个从机对话 for(i=1;i);break;case -:address=3;LCD_write_string(4,0,3);break;case =: out_485(address,key);break;case C:j=0;LCD_write_string(7,0, );break;default: if(j8&i=0)keyj+=i;LCD_write_char(j+6,0,i);LCD_wr

6、ite_string(4,1,inbox);LCD_write_string(12,1, );/数组没有结束符,所以要修正液晶后面多余的乱码/- 从机部分：#include #include #include 1602.h #include delay.h #include usart.h #include crc8.h /CRC校验函数就在这个文件里面 #define amount 10 /设定通讯数据量(包括1个地址帧,n个数据帧,1个校验帧) #define address 2 /请在这里设定本机地址 unsigned char sendamount; /发件箱 unsigned cha

7、r inboxamount; /收件箱 unsigned char n=0; /记忆中断次数 unsigned char flag_me=0; /个人数据标志unsigned char flag_all=0; /广播数据标志/-从机接收子程序- #pragma interrupt_handler RXC_Int: 12void RXC_Int(void) /接收中断 unsigned char ERROR=0; if( UCSRA&0x04 | UCSRA&0x10 ) ERROR=1; /记录奇偶效验错误或者帧错误 inboxn=UDR; /把接收到的数据保存到收件箱 n+;/记忆接收的次数

8、 if(ERROR) /如果通讯有错. /n=0; /接收计数清0 inbox0=0; /把地址改为无效地址0 UCSRA|=0x01; /重新打开接收器的地址帧筛选功能 /如果地址匹配本机或者是广播地址就关闭地址筛选(多机通讯)功能 (关闭是为了保证后面的数据全部接收到)if(inbox0=address |inbox0=0xff) UCSRA&=0x01; if(n=amount) /接收到amount个数据以后. n=0; /接收计数清0 UCSRA|=0x01; /重新打开接收器的地址帧筛选功能 if(inboxamount-1=crc8(inbox,amount-1) /如果crc8

9、校验正确就. if(inbox0=address)flag_me=1; /本机地址/接收完数据后会置标志位,在读取数据后要把标志位置零 if(inbox0=255) flag_me=1; /广播地址,接收后不要回复/接收完数据后会置标志位,在读取数据后要把标志位置零 void out_485(unsigned char *ptr)unsigned char i;send0=1; /发件箱地址指向主机 for(i=1;iamount-1;i+)send=*ptr+;/把发送的数据方到发信箱 sendamount-1=crc8(send,amount-1); /计算发件箱的crc8校验码 usar

10、t_out(send,amount); /将发件箱的数据send发送出去/-主函数-void main(void) usart_init(); SEI(); LCD_init();LCD_write_string(0,0,out:);LCD_write_string(0,1,int:);while (1) while(flag_me) LCD_write_string(4,1,inbox);n=0; /中断次数清0 inbox0=0; /收件箱地址清0 flag_me=0;out_485(2,ok!);LCD_write_string(4,0,send);LCD_write_string(13

11、,0, );LCD_write_string(13,1, ); /end这是我用ATmega162做的协议转换的程序，带通讯协议，RS485就是在RS232的程序基础上加上发送和接收的控制即可，用CVAVR软件编的，如果有不明白之处，请发信息void ReturnXMTA808(unsigned char pvAddr);void putchar1(char c);#define RXB8 1#define TXB8 0#define UPE 2#define OVR 3#define FE 4#define UDRE 5#define RXC 7#define FRAMING_ERROR (

12、1FE)#define PARITY_ERROR (1UPE)#define DATA_OVERRUN (1OVR)#define DATA_REGISTER_EMPTY (1UDRE)#define RX_COMPLETE (1RXC) unsigned int tempdat=0; char ttup=0; char ttdown=0; char temp=0; char SlaveAddr=0;/ USART0 Receiver buffer#define RX_BUFFER_SIZE0 8char rx_buffer0RX_BUFFER_SIZE0;unsigned char rx_w

13、r_index0,rx_counter0;/rx_rd_index0,/ This flag is set on USART0 Receiver buffer overflowbit rx_buffer_overflow0;/bit slaveokflag;/ USART0 Receiver interrupt service routine/gather XMTA808interrupt USART0_RXC void usart0_rx_isr(void)char status,data;status=UCSR0A;data=UDR0;if (status & (FRAMING_ERROR

14、 | PARITY_ERROR | DATA_OVERRUN)=0) rx_buffer0rx_wr_index0=data; if (+rx_wr_index0 = RX_BUFFER_SIZE0) rx_wr_index0=0; if (+rx_counter0 = RX_BUFFER_SIZE0) if(rx_buffer02=0x55) rx_wr_index0=0; rx_counter0=0; rx_buffer_overflow0=1; / return current temperature tempdat = (unsigned int)(unsigned int)(rx_b

15、uffer01*0x100)+(rx_buffer00); ttup = (char)(tempdat&0x03ff)/100)&0x0f; temp = (char)(tempdat%100); ttdown = bin2bcd(temp); EnRS485M; putchar1(0x3a); putchar1(SlaveAddr); putchar1(0x03); putchar1(0x00); putchar1(ttup); putchar1(ttdown); putchar1(0x0D); putchar1(0x0A); putchar1(0x0D); putchar1(0x0A);

16、DiRS485M; else /worry & re rx_counter0=0;rx_wr_index0=0; ReturnXMTA808(SlaveAddr); / Write a character to the USART0 Transmittervoid putchar(char c)while (UCSR0A & DATA_REGISTER_EMPTY)=0);UDR0=c;/ USART1 Receiver buffer#define RX_BUFFER_SIZE1 8char rx_buffer1RX_BUFFER_SIZE1;/ This flag is set on USA

17、RT1 Receiver buffer overflowbit RevReadyflag; bit RevDatflag; bit EndCRflag; bit EndLFflag; char Longcode=0; / USART1 Receiver interrupt service routineinterrupt USART1_RXC void usart1_rx_isr(void)char status,SBUF;status=UCSR1A;SBUF=UDR1;rx_counter0=0;rx_wr_index0=0;if (status & (FRAMING_ERROR | PAR

18、ITY_ERROR | DATA_OVERRUN)=0) if(SBUF = 0x3a) & (RevReadyflag = 0) RevReadyflag = 1; RevDatflag = 0; EndCRflag = 0; EndLFflag = 0; else if(SBUF = 0x11 |SBUF = 0x12) & (RevReadyflag=1) & (RevDatflag=0) RevDatflag=1; Longcode=0x00; SlaveAddr = SBUF; else RevReadyflag=0; /- if(RevDatflag=1) & (SBUF!=0x0

19、d) & (SBUF!=0x0a) rx_buffer1Longcode=SBUF; Longcode+; else if(SBUF=0x0d) & (RevDatflag=1)EndCRflag=1; else if(SBUF=0x0a) & (EndCRflag=1) & (RevDatflag=1) EndLFflag=1; RevReadyflag=0; RevDatflag=0; Longcode=0; switch(rx_buffer11) case 0x03: ReturnXMTA808(SlaveAddr);break; case 0x08: EnRS485M; putchar

20、1(0x3a); /loopback putchar1(SlaveAddr); putchar1(0x08); putchar1(0x0D); putchar1(0x0A); putchar1(0x0D); putchar1(0x0A); DiRS485M; break; default:break; void putchar1(char c)while (UCSR1A & DATA_REGISTER_EMPTY)=0);UDR1=c;voidReturnXMTA808(char pvAddr) EnRS485S; putchar(pvAddr+0x80); putchar(pvAddr+0x80); putchar(0x52); putchar(0x00); putchar(0x00); putchar(0x00); putchar(0x52+pvAddr); putchar(0x00); rx_counter0=0;rx_wr_index0=0; DiRS485S;