谁有arm开发板读取gps信息的程序，希望最好有注释

只看该作者 · 2013-8-23 16:55

我这有个程序看不太懂，有大神能给我注释一些吗，谢谢了ARM开发板上GPS信息的读取 (2007-07-22 10:27)
分类： S3C2410
硬件平台：开发板创维特jx2410，gps模块HOLUX GR-87，USB转串口线一条。程序是在嵌入式linux操作系统下读串口实现。源代码如下：

#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 "serial.h"
//
#define UInt32    unsigned int
#define Int16    short
#define UInt16    unsigned short
#define UInt8    unsigned char
#define Boolean int
#define false    0
#define true    1
#define GPS_RECV_CMD_MAX_BUF 256 //the buffer size

//the gga info struct
typedef struct GGAINFO{
int bIsGPGGA;
UInt8  hour, bjhour, min, sec, secFrac;
double latitude;
UInt8  latNS;
double longitude;
UInt8  lgtEW;
// UInt8  hour, bjhour, min, sec, secFrac;
UInt8  satellites;
Int16  altitude;
// UInt8  altUnit;
}GGAINFO;
int main(void)
{
int fd;
int i;
char buffer[GPS_RECV_CMD_MAX_BUF];//receive buffer
char tmp;
GGAINFO ggainfo;
char Degree[4];
char Minute[8];
char Hour[4];
char Minu[4];
char Second[4];
char Satnum[4];
int no = 0;
//open the COM
if((fd=open_port(fd,4))<0)
{
  perror("open_port error");
  return;
}
printf("fd=%d\n",fd);
//set the COM
if((i=set_opt(fd,9600,8,'N',1))<0)
{
  perror("set_opt error");
  return;
}
//
while(1)
{
  while(!Is_startGP(fd));
//  printf("start to receive\n");

  //receive the info
  for(i = 0; i<GPS_RECV_CMD_MAX_BUF;i++)
  {
read(fd,&tmp,1);
buffer[i]=tmp;
// printf("%c",buffer[i]);
if(tmp=='\n')break;
  }
//  printf("\n");
  //proc the GGA info
  if(Is_GGA(buffer))
  {
ggainfo.bIsGPGGA = 1;
//Time:6-15
no = 6;
for(i = 0;i < 4;i++)
Hour[i]=0;
Hour[0]=buffer[no];
Hour[1]=buffer[no+1];

no += 2;
for(i = 0;i < 4;i++)
Minu[i]=0;
Minu[0]=buffer[no];
Minu[1]=buffer[no+1];
no += 2;
for(i = 0;i < 4;i++)
Second[i]=0;
Second[0]=buffer[no];
Second[1]=buffer[no+1];
ggainfo.hour = atoi(Hour);
ggainfo.min = atoi(Minu);
ggainfo.sec = atoi(Second);
ggainfo.secFrac = 0;
ggainfo.bjhour = ggainfo.hour + 8;
if(ggainfo.bjhour > 24)
ggainfo.bjhour -=  24;

//Latitude:17-25
no = 17;
for(i = 0;i < 4;i++)
Degree[i]=0;
Degree[0]=buffer[no];
Degree[1]=buffer[no+1];
no+=2;
for(i=0;i<8;i++)
Minute[i]=0;
for(i=0;i<7;i++)
Minute[i]=buffer[no+i];
// int l=atoi(Degree);
ggainfo.latitude=(atof(Minute)) / 60.0 + atoi(Degree);

//NS:27
ggainfo.latNS = buffer[27];

//Longitude:29-38
no = 29;
for(i=0;i<4;i++)
Degree[i]=0;
Degree[0]=buffer[no];
Degree[1]=buffer[no+1];
Degree[2]=buffer[no+2];
no+=3;
for(i=0;i<8;i++)
Minute[i]=0;
for(i=0;i<7;i++)
Minute[i]=buffer[no+i];
// int B=atoi(Degree);
ggainfo.longitude=(atof(Minute)) / 60.0 + atoi(Degree);
//WE:40
ggainfo.lgtEW = buffer[40];

//the number of satellite:44-45
no = 44;
for(i = 0;i < 4;i++)
Satnum[i]=0;
Satnum[0]=buffer[no];
Satnum[1]=buffer[no+1];
ggainfo.satellites = atoi(Satnum);

printf("UTC Time:%d h %d m %d s\n",ggainfo.hour,ggainfo.min,ggainfo.sec);
printf("BJ Time:%d h %d m %d s\n",ggainfo.bjhour,ggainfo.min,ggainfo.sec);
printf("Latitude:%c wei %f \n",ggainfo.latNS,ggainfo.latitude);
printf("Longitude:%c jing %f \n",ggainfo.lgtEW,ggainfo.longitude);
printf("Satellites:%d \n",ggainfo.satellites);
printf("\n");
  }
  else continue;
  sleep(1);
}
close(fd);
return 0;
}

int Is_startGP(int fp)
{
int status=0;
char cc,tmp;
read(fp,&cc,1);
tmp=cc;
if(tmp=='$')status=1;
return status;
}

int Is_GGA(char p[GPS_RECV_CMD_MAX_BUF])
{
int status=0;
if(p[2] == 'G' && p[3] == 'G' && p[4] == 'A')
  status=1;
return status;
}

谁有arm开发板读取gps信息的程序，希望最好有注释

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