c语言串口发送字节数,一个关于51单片机串口数据发送问题（c语言）？

你的问题是刚判断完帧头就处理数据了

应该判断完帧头后继续接受3个字节的数据再处理

#include

#include

#define uchar unsigned char

#define uint  unsigned int

int 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==2)          //收到7F开头数组  //■■■■■■■■此处有改动

{

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=4)//■■■■■■■■此处有改动

{//■■■■■■■■此处有改动

flag=2;//■■■■■■■■此处有改动

}            //■■■■■■■■此处有改动

}

}

if (SBUF==0x7F)后面那两句能不能加个花括号括起来先……

那个校验的数组8*32什么作用啊？。

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