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fl2440开发板添加GPS模块
1.1 GPS模块与ARM开发板的连接
GPS模块属于字符设备,只需要和FL2440开发的第二个串口连接既可以,然后将GPS测试模块放在室外便可以每隔一段时间向开发板的串口发一个数据包,
~ >: microcom /dev/ttyS1 -s 4800
$GPGGA,024907.000,3029.6642,N,11423.6203,E,1,10,1.0,35.7,M,-13.7,M,,0000*41
$GPGSA,A,3,04,08,32,17,28,30,07,11,20,01,,,1.9,1.0,1.7*3B
$GPRMC,024907.000,A,3029.6642,N,11423.6203,E,0.07,244.07,210914,,,A*67
$GPGGA,024908.000,3029.6643,N,11423.6202,E,1,10,1.0,35.3,M,-13.7,M,,0000*4A
$GPGSA,A,3,04,08,32,17,28,30,07,11,20,01,,,1.9,1.0,1.7*3B
$GPGSV,3,1,11,04,78,178,38,01,74,066,31,30,56,242,44,11,54,043,31*75
$GPGSV,3,2,11,28,47,328,27,07,40,194,40,08,31,177,47,17,29,277,27*74
$GPGSV,3,3,11,20,23,145,36,32,21,098,33,19,15,059,*4C
$GPRMC,024908.000,A,3029.6643,N,11423.6202,E,0.09,238.16,210914,,,A*6D
$GPGGA,024909.000,3029.6643,N,11423.6202,E,1,10,1.0,35.0,M,-13.7,M,,0000*48
$GPGSA,A,3,04,08,32,17,28,30,07,11,20,01,,,1.9,1.0,1.7*3B
$GPRMC,024909.000,A,3029.6643,N,11423.6202,E,0.07,251.95,210914,,,A*66
。。。
1.1 GPS数据解析
GPS数据如何理解呢?这一大串的数据到底代表了什么意思呢?要想编写GPS数据解析程序,肯定要知道这些数据代表什么,还要知道如何转换这些数据。以下给出一个博客链接详细地说明了GPS数据,这里不在做赘述:
http://www.cnblogs.com/csMapx/archive/2011/11/02/2232663.html
1.1 ARM+linux串口编程介绍
其实编写GPS数据解析程序就是ARM+linux串口编程,串口编程是嵌入式应用程序开发中最基础也是最重要的部分,如何从一个串口设备获取数据并将这些数据做一定的解析呢?OK,串口编程大致可以分为以下几个步骤:
至于串口编程的详细介绍,如何设置波特率,如何设置停止位等等,以下给出两个linux串口编程的博客链接,讲的很详细,不再赘述:
http://www.cnblogs.com/wblyuyang/archive/2011/11/21/2257544.html
http://blog.csdn.net/mtv0312/article/details/6599162
1.4 编写一个简单的GPS数据解析程序
这个程序比较简单,只是一个测试GPS数据的程序,GPS数据当中的GPRMC数据就可以用来做导航信息用了,包含了经度、纬度、日期时间等等!如果你们想做一个比较完善的GPS数据解析程序,可以在我的基础上进行修改,比如加上GPS数据出错处理、GPS数据超时处理等等!
OK,我先说一下我的代码包含以下这几个文件:gps_test.c gps_analysis.c set_com.c gpsd.h主函数在gps_test.c文件中,gps_analysis.c主要是GPS数据解析函数设计,set_com.c主要是设置GPS串口设备函数设计,gpsd.h是头文件!
1.4.1 编写gps_test.c测试程序
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include <stdlib.h>
#include "gpsd.h"
#define GPS_LEN 512 /* GPS数据长度宏定义 */
int main (int argc, char **argv)
{
int fd = 0;
int nread = 0;
GPRMC gprmc;
//GPRMC *gprmc;
char gps_buff[GPS_LEN];
char *dev_name = "/dev/ttyS1";
fd = open_com(dev_name);
set_opt(fd,4800,8,‘N‘,1);
while(1)
{
sleep(2); //注意这个时间的设置,设置不恰好的话,会导致GPS数据读取不完成,数据解析出错误
nread = read(fd,gps_buff,sizeof(gps_buff));
//printf("gps_buff: %s", gps_buff);
memset(&gprmc, 0 , sizeof(gprmc));
gprmc_analysis(gps_buff, &gprmc);
if(nread > 0)
{
printf("=========== GPS全球定位模块 ==============\n");
printf("== 开发者:曾宪炀 ==\n");
printf("== 版本: 1.0.0 ==\n");
printf("===========================================\n");
printf("===========================================\n");
printf("= GPS状态位 : %c [A:有效状态 V:无效状态]=\n" ,gprmc.pos_state);
printf("= GPS模式位 : %c [A:自主定位 D:差分定位]=\n" , gprmc.mode);
printf("=日期 : 20%02d-%02d-%02d=\n", gprmc.date%100, (gprmc.date%10000)/100,
gprmc.date/10000);
printf("=时间 : %02d:%02d:%02d=\n",(gprmc.time/10000+8)%24,(gprmc.time%10000)/100,
gprmc.time%100);
printf("=纬度 : 北纬:%.3f=\n",(gprmc.latitude/100));
printf("=经度 : 东经:%.3f=\n",(gprmc.longitude/100));
printf("=速度 : %.3f =\n",gprmc.speed);
printf("===========================================\n");
}
}
close(fd);
return 0;
} /* ----- End of main() ----- */
1.4.2 编写gps_analysis.cGPS数据解析函数
/*********************************************************************************
* Copyright: (C) 2014 lingyun
* All rights reserved.
*
* Filename: gps_analysis.c
* Description: This file
*
* Version: 1.0.0(2014年09月09日)
* Author: skyyang <790549341@qq.com>
* ChangeLog: 1, Release initial version on "2014年09月09日 04时21分53秒"
*
********************************************************************************/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "gpsd.h"
int gprmc_analysis (char *buff,GPRMC *gprmc)
{
char *ptr = NULL;
if(gprmc == NULL)
return -1;
if(strlen(buff) < 10)
return -1;
if(NULL == (ptr = strstr(buff,"$GPRMC")))
return -1;
sscanf(ptr,"$GPRMC,%d.000,%c,%f,N,%f,E,%f,%f,%d,,,%c*",\
&(gprmc->time),&(gprmc->pos_state),&(gprmc->latitude),&(gprmc->longitude),&(gprmc->speed),&(gprmc->direction),&(gprmc->date),&(gprmc->mode));
return 0;
} /* ----- End of gprmc_analysis() ----- */
1.4.3 编写set_com.c GPS串口设备配置函数
/*********************************************************************************
* Copyright: (C) 2014
* All rights reserved.
*
* Filename: set_com.c
* Description: This file
*
* Version: 1.0.0(2014年09月09日)
* Author:
* ChangeLog: 1, Release initial version on "2014年09月09日 04时15分06秒"
*
********************************************************************************/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include <sys/types.h>
#include <stdlib.h>
#include "gpsd.h"
int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop)
{
struct termios newtio,oldtio;
if( tcgetattr( fd,&oldtio) != 0)
{
perror("SetupSerial 1");
return -1;
}
bzero( &newtio, sizeof( newtio ) );
newtio.c_cflag |= CLOCAL | CREAD;
newtio.c_cflag &= ~CSIZE;
switch( nBits )
{
case 7:
newtio.c_cflag |= CS7;
break;
case 8:
newtio.c_cflag |= CS8;
break;
}
switch( nEvent )
{
case ‘O‘: //奇校验
newtio.c_cflag |= PARENB;
newtio.c_cflag |= PARODD;
newtio.c_iflag |= (INPCK | ISTRIP);
break;
case ‘E‘: //偶校验
newtio.c_iflag |= (INPCK | ISTRIP);
newtio.c_cflag |= PARENB;
newtio.c_cflag &= ~PARODD;
break;
case ‘N‘:
newtio.c_cflag &= ~PARENB;
break;
}
switch( nSpeed )
{
case 2400:
cfsetispeed(&newtio, B2400);
cfsetospeed(&newtio, B2400);
break;
case 4800:
cfsetispeed(&newtio, B4800);
cfsetospeed(&newtio, B4800);
break;
case 9600:
cfsetispeed(&newtio, B9600);
cfsetospeed(&newtio, B9600);
break;
case 115200:
cfsetispeed(&newtio, B115200);
cfsetospeed(&newtio, B115200);
break;
default:
cfsetispeed(&newtio, B9600);
cfsetospeed(&newtio, B9600);
break;
}
if( nStop == 1 )
{
newtio.c_cflag &= ~CSTOPB;
}
else if ( nStop == 2 )
{
newtio.c_cflag |= CSTOPB;
}
newtio.c_cc[VTIME] = 0;
newtio.c_cc[VMIN] = 0;
tcflush(fd,TCIFLUSH);
if((tcsetattr(fd,TCSANOW,&newtio))!=0)
{
perror("com set error");
return -1;
}
return 0;
}
int open_com(char *device_name)
{
int fd = 0;
if (0 > (fd = open(device_name, O_RDWR|O_NOCTTY|O_NDELAY))) //要设置非阻塞模式打开设备否则会出错!
{
perror("Open Comport Fail:");
return 0;
}
return fd;
}/* ----- End of open_com() ----- */
1.4.4 编写gpsd.h头文件
#ifndef __GPSD_H__
#define __GPSD_H__
typedef unsigned int UINT; //add by wei
typedef int BYTE; //add by wei
typedef long int WORD; //add by wei
typedef struct __gprmc__
{
UINT time; //时间
char pos_state; //定位状态
float latitude; //纬度
float longitude; //经度
float speed; //移动速度
float direction; //方向
UINT date; //日期
float declination; //磁偏角
char dd; //磁偏角方向
char mode;
} GPRMC;
extern int open_com(char *device_name);
extern int gprmc_analysis(char *buff,GPRMC *gprmc);
extern int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop);
#endif
1.5 编译下载GPS数据解析程序到开发板上
1.交叉编译器编译GPS数据解析程序,这里最好自己写一个makefile
[weishusheng@localhost gps_yang]$ ls
gps_analysis.c gpsd.h gps_test gps_test.c makefile set_com.c version.h
[weishusheng@localhost gps_yang]$ /opt/buildroot-2011.11/arm920t/usr/bin/arm-linux-gcc set_com.c gps_test.c gps_analysis.c -o gps_wei_test
[weishusheng@localhost gps_yang]$ ls
gps_analysis.c gpsd.h gps_test.c gps_wei_test set_com.c
生成gps_wei_test
2.在开发板上直接运行gps_test可执行程序,便可以获取解析后的GPS数据了:
/fl2440/gps >: ./gps_wei_test
gps infomation :8,53,332,24,30,52,231,43*77
$GPGSV,3,2,12,11,47,043,15,07,33,192,48,17,32,284,34,20,28,140,14*7C
$GPGSV,3,3,12,08,24,176,47,32,23,091,13,19,11,064,22,06,03,218,24*7F
$GPRMC,030323.000,A,3029.6405,N,11423.6222,E,0.34,332.13,210914,,,A*69
$GPGGA,030324.000,3029.6408,N,11423.6220,E,1,09,1.0,106.1,M,-13.7,M,,0000*7D
$GPGSA,A,3,04,08,28,30,07,17,01,11,19,,,,1.8,1.0,1.5*33
$GPRMC,030324.000,A,3029.6408,N,11423.6220,E,0.29,346.94,210914,,,A*61
$GPGGA,030325.000,3029.6410,N,11423.6218,E,1,09,1.0,105.2,M,-13.7,M,,0000*7E
$GPGSA,A,3,04,08,28,30,07,17,01,11,19,,,,1.8,1.0,1.5*33
$GPRMC,030325.000,A,3029.6410,N,11423.6218,E,0.28,315.50,210914,,,A*6D
$GPGGA,030326.000,3029.6412,N,11423.6216,E,1,09,1.0,104.5,M,-13.7,M,,0000*77
$GPGSA,A,3,04,08,28,30,07,17,01,11,19,,,,1.8,1.0,1.5*33
$GPRMC,030326.000,A,3029.6412,N,11423.621=========== GPS全球定位模块 ==============
== 开发者:weishusheng ==
== 版本: 1.0.0 ==
============================================
============================================
= GPS状态位 : A [A:有效状态 V:无效状态]=
日期 : 2014-09-21
时间 : 11:03:23
纬度 : 北纬:30.296
经度 : 东经:114.236
速度 : 0.340
到此,我们的GPS定位成功!
fl2440开发板添加GPS模块