程序能够实现要求,但不是想要的结果。
原因:当首次接收到7F 00 01 07的时候单片机不会发送11 88这个正确校验码,而是发送0D 80错误校验码;再次接收到7F 00 01 07的时候才会发送11 88;以此类推发送正确的校验码都上次数组的校验码。而不是当时接收数组的校验码。总之,发送的校验码都要慢半拍。程序如下,谢谢分析。
程序编译0错误、0警告;#include <reg52.h>#include <intrins.h>#define uchar unsigned char#define uint unsigned intint zhibi_js[40], i0, com_dat;unsigned char a,b,c,flag;uchar Crcl,Crch;const uint code CrcTable[8*32]={0x0000,0x8005,0x800F,0x000A,0x801B,0x001E,0x0014,0x8011,0x8033,0x0036,0x003C,0x8039,0x0028,0x802D,0x8027,0x0022,0x8063,0x0066,0x006C,0x8069,0x0078,0x807D,0x8077,0x0072,0x0050,0x8055,0x805F,0x005A,0x804B,0x004E,0x0044,0x8041,0x80C3,0x00C6,0x00CC,0x80C9,0x00D8,0x80DD,0x80D7,0x00D2,0x00F0,0x80F5,0x80FF,0x00FA,0x80EB,0x00EE,0x00E4,0x80E1,0x00A0,0x80A5,0x80AF,0x00AA,0x80BB,0x00BE,0x00B4,0x80B1,0x8093,0x0096,0x009C,0x8099,0x0088,0x808D,0x8087,0x0082,0x8183,0x0186,0x018C,0x8189,0x0198,0x819D,0x8197,0x0192,0x01B0,0x81B5,0x81BF,0x01BA,0x81AB,0x01AE,0x01A4,0x81A1,0x01E0,0x81E5,0x81EF,0x01EA,0x81FB,0x01FE,0x01F4,0x81F1,0x81D3,0x01D6,0x01DC,0x81D9,0x01C8,0x81CD,0x81C7,0x01C2,0x0140,0x8145,0x814F,0x014A,0x815B,0x015E,0x0154,0x8151,0x8173,0x0176,0x017C,0x8179,0x0168,0x816D,0x8167,0x0162,0x8123,0x0126,0x012C,0x8129,0x0138,0x813D,0x8137,0x0132,0x0110,0x8115,0x811F,0x011A,0x810B,0x010E,0x0104,0x8101,0x8303,0x0306,0x030C,0x8309,0x0318,0x831D,0x8317,0x0312,0x0330,0x8335,0x833F,0x033A,0x832B,0x032E,0x0324,0x8321,0x0360,0x8365,0x836F,0x036A,0x837B,0x037E,0x0374,0x8371,0x8353,0x0356,0x035C,0x8359,0x0348,0x834D,0x8347,0x0342,0x03C0,0x83C5,0x83CF,0x03CA,0x83DB,0x03DE,0x03D4,0x83D1,0x83F3,0x03F6,0x03FC,0x83F9,0x03E8,0x83ED,0x83E7,0x03E2,0x83A3,0x03A6,0x03AC,0x83A9,0x03B8,0x83BD,0x83B7,0x03B2,0x0390,0x8395,0x839F,0x039A,0x838B,0x038E,0x0384,0x8381,0x0280,0x8285,0x828F,0x028A,0x829B,0x029E,0x0294,0x8291,0x82B3,0x02B6,0x02BC,0x82B9,0x02A8,0x82AD,0x82A7,0x02A2,0x82E3,0x02E6,0x02EC,0x82E9,0x02F8,0x82FD,0x82F7,0x02F2,0x02D0,0x82D5,0x82DF,0x02DA,0x82CB,0x02CE,0x02C4,0x82C1,0x8243,0x0246,0x024C,0x8249,0x0258,0x825D,0x8257,0x0252,0x0270,0x8275,0x827F,0x027A,0x826B,0x026E,0x0264,0x8261,0x0220,0x8225,0x822F,0x022A,0x823B,0x023E,0x0234,0x8231,0x8213,0x0216,0x021C,0x8219,0x0208,0x820D,0x8207,0x0202};/**************************** 校验查表算法****************************/void UpdateCrc(const uchar num){ uint table_addr; table_addr=(num ^ Crch); Crch=(CrcTable[table_addr] >> 8) ^ Crcl; Crcl=(CrcTable[table_addr] & 0x00FF);}/**************************** 高低位置高电平****************************/void ResetCrc(void){Crcl=0xFF;Crch=0xFF;} /*************************** UART初始化 波特率:9600***************************/void UART_init(void){ SCON = 0x50; // 10位uart,允许串行接受 TMOD = 0x21; // 定时器1工作在方式2(自动重装) TH1 = 0xfd; TL1 = 0xfd; IE = 0x82; TR1 = 1; ES=1;}/*************************** UART 发送一字节***************************/void UART_send_byte(unsigned char dat){ SBUF = dat; while (!TI); TI = 0;}/*************************** 数组第二位判断***************************/unsigned char panduan (){ if(zhibi_js[1]==0x00) return 1; //第二位是0x00为真 //判断a值为1 if(zhibi_js[1]==0x80) return 1; //第二位是0x80为真 else return 0; //否则为假}/**************************** 7F开头数组接受判断****************************/void wr_test(void){ if(flag==1) //收到7F开头数组 { a=panduan(); //数组第二位判断 flag=0; //有效数组标志清零 }}/****************************************** 主函数 对符合要求数组进行校验并串口输出校验码*******************************************/void main(void) { UART_init(); //串口初始化 while(1) { wr_test(); //判断是否有符合数组 if(a==1) { a=0; b=(zhibi_js[2]+3); //由接收数组的第三个元素确定b的值 ResetCrc(); //置高电平 for(i0=1;i0<b;i0++) UpdateCrc(zhibi_js[i0]); //对接收数组进行计算 zhibi_js[i0++]=Crcl; //得出低8位校验码 zhibi_js[i0++]=Crch; //得出高8位校验码 UART_send_byte(Crcl); //串口输出低8位校验码 UART_send_byte(Crch); //串口输出低8位校验码 } } } /*************************** 串口接收**************************/void Com_Int(void) interrupt 4{ if(RI == 1) { if(SBUF == 0x7F) com_dat=0,flag=1; //接收7F开头的数组 zhibi_js[com_dat++] = SBUF; //串口接收数组 RI = 0; } }
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