新年第一帖，，请给位大哥说说怎么接收一串字符呢，谢谢

guxingganyue

我想接收一固定的字符串，用串口接收，，单片机用ATmega48，请各位大哥指点一下

这是数据：
$GPGGA,021718.000,3903.5118,N,11707.3802,E,2,07,1.5,-0.5,M,-3.1,M,3.8,0000*4E
$GPGSA,A,3,28,10,05,20,23,13,17,,,,,,2.1,1.5,1.5*38
$GPGSV,3,1,11,04,69,324,,17,56,117,34,10,51,199,45,02,40,279,*7F
$GPGSV,3,2,11,12,29,305,,23,22,073,27,13,21,109,37,20,16,045,25*78
$GPGSV,3,3,11,05,08,214,33,28,07,174,32,42,38,146,37*47
$GPRMC,021718.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*74
$GPVTG,,T,,M,0.00,N,0.0,K,D*16
$GPGGA,021719.000,3903.5118,N,11707.3802,E,2,06,2.1,-0.5,M,-3.1,M,1.8,0000*4B
$GPRMC,021719.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*75
$GPVTG,,T,,M,0.00,N,0.0,K,D*16

$GPGGA,021720.000,3903.5118,N,11707.3802,E,2,07,1.2,-0.5,M,-3.1,M,1.8,0000*40
$GPRMC,021720.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*7F
$GPVTG,,T,,M,0.00,N,0.0,K,D*16

$GPGGA,021721.000,3903.5118,N,11707.3802,E,2,08,1.0,-0.5,M,-3.1,M,1.8,0000*4C
$GPRMC,021721.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*7E
$GPVTG,,T,,M,0.00,N,0.0,K,D*16

$GPGGA,021722.000,3903.5118,N,11707.3802,E,2,08,1.0,-0.5,M,-3.1,M,1.8,0000*4F
$GPRMC,021722.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*7D
$GPVTG,,T,,M,0.00,N,0.0,K,D*16

$GPGGA,021723.000,3903.5118,N,11707.3802,E,2,07,1.2,-0.5,M,-3.1,M,2.8,0000*40
$GPGSA,A,3,28,10,02,05,23,13,17,,,,,,2.0,1.2,1.6*3D
$GPGSV,3,1,11,04,69,324,,17,56,117,34,10,51,199,45,02,40,279,14*7A
$GPGSV,3,2,11,12,29,305,,23,22,073,26,13,21,109,37,20,16,045,25*79
$GPGSV,3,3,11,05,08,214,33,28,07,174,31,42,38,146,37*44
$GPRMC,021723.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*7C
$GPVTG,,T,,M,0.00,N,0.0,K,D*16
$GPGGA,021724.000,3903.5118,N,11707.3802,E,2,07,1.2,-0.5,M,-3.1,M,3.8,0000*46
$GPRMC,021724.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*7B
$GPVTG,,T,,M,0.00,N,0.0,K,D*16

$GPGGA,021725.000,3903.5118,N,11707.3802,E,2,07,1.2,-0.5,M,-3.1,M,4.8,0000*40
$GPRMC,021725.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*7A
$GPVTG,,T,,M,0.00,N,0.0,K,D*16

$GPGGA,021726.000,3903.5118,N,11707.3802,E,2,07,1.2,-0.5,M,-3.1,M,1.8,0000*46
$GPRMC,021726.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*79
$GPVTG,,T,,M,0.00,N,0.0,K,D*16

$GPGGA,021727.000,3903.5118,N,11707.3802,E,2,08,1.0,-0.5,M,-3.1,M,1.8,0000*4A
$GPRMC,021727.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*78
$GPVTG,,T,,M,0.00,N,0.0,K,D*16




这是我的串口接收中断处理程序：
#pragma interrupt_handler uart0_rx_isr:19
void uart0_rx_isr(void)
{
     unsigned char GPS_Temp_Data=UDR0;
     //unsigned char GPS_Data_OK=0;//GPS数据接收完毕标志
    //static uint8 GPS_Data[60];  //GPS有效数据存储空间
     static uint8 GPS_Data_Count=6; //GPS有效数据头“$GPRMC”到来标志
     static uint8 GPS_Data_Flag=0; //GPS有效数据头“$GPRMC”到来标志
     /*-------------检测数据头是否为所要的数据头---------------*/
     if(GPS_Temp_Data=='$')
         GPS_Data[0]='$';
     else if(GPS_Temp_Data=='G')
         GPS_Data[1]='G';
     else if(GPS_Temp_Data=='P')
         GPS_Data[2]='P';
     else if(GPS_Temp_Data=='R')
         GPS_Data[3]='R';
     else if(GPS_Temp_Data=='M')
         GPS_Data[4]='M';
     else if(GPS_Temp_Data=='C')
     {
         GPS_Data[5]='C';
         GPS_Data_Flag=1;
     }
     
     /*--------数据头检测成功-----------*/
     if(GPS_Data_Flag==1)
     {
         //接收有效的GPS数据
         GPS_Data[GPS_Data_Count ++]=GPS_Temp_Data;
         //想要的数据接收完毕（判断是否接收到 D）
         if(GPS_Temp_Data=='D')
         {
             GPS_Data_Flag=0;
             GPS_Data_OK=1;
         }
     }      
}


我只想把 “ $GPRMC,021718.000,A,3903.5118,N,11707.3802,E,0.00,,220111,,,D*74 ”用串口收下，但我的程序接收的效果不是很好
有时接收的正确，有时接收的就不是这一串字符，，请各位指点

zxq6

中断里面直观copy到内存缓冲，在主循环里面去处理。

guxingganyue

回复【1楼】zxq6 小马哈
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大哥能说明白点吗？

lcw_swust

数据头的检测好像有问题
    else if(GPS_Temp_Data=='C')
     {
         GPS_Data[5]='C';
         GPS_Data_Flag=1;
     }
如果开始时收到'C',这个if不就成立了吗?
还是用状态机吧:
http://bbs.dzsc.com/space/viewspacepost.aspx?postid=52942

guxingganyue

回复【3楼】lcw_swust 小李飞刀
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我也这么想过，，但观察数据后发现只有那句话才有  C ，所以可以算是勉强正确吧