main.c

编写一个模拟GPS的应用程序

/************************************************
 *  GPS read demo ,use com2
 *  by Zou jian guo <[e-mail]>   
 *  2004-10-22
 *
*************************************************/


#include <termios.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/signal.h>
#include <pthread.h>
#include "gps.h"

#define BAUDRATE B4800
#define COM3 "/dev/ttyS2"
#define ENDMINITERM 27 /* ESC to quit miniterm */
#define FALSE 0
#define TRUE 1
volatile int STOP=FALSE;
volatile int fd;
GPS_INFO gps_info;
int GET_GPS_OK=FALSE;
char GPS_BUF[1024];
/*---当ESC键按下时将终止程序运行--------------------------------*/
void* keyboard(void * data)
{
    int c;
	for (;;){
		if((c=getchar()) == ENDMINITERM){
       		STOP=TRUE;
       		break ;
		}
	}
    return NULL;
}
/*-显示GPS信息----------------------------------------*/
void* show_gps_info(void * data)
{
	while(1){
		if(GET_GPS_OK){
			GET_GPS_OK=FALSE;
			printf("%s",GPS_BUF);
			gps_parse(GPS_BUF,&gps_info);
			show_gps(&gps_info);
		}
		usleep(100);
		if(STOP)break;
	}

}
/*-接收GPS数据---------------------------------------------*/
void* receive(void * data)
{
	int i=0;
	char c;
	char buf[1024];
	GPS_INFO GPS;
  	printf("read modem\n");
  	while (STOP==FALSE) //没有结束
  	{
    	read(fd,&c,1); /* 读一个字符 */
    	buf[i++] = c;
		if(c == '\n'){
			strncpy(GPS_BUF,buf,i);
			i=0;
			GET_GPS_OK=TRUE;
		}
		if(STOP)break;
  	}
  	printf("exit from reading modem\n");
  	return NULL; 
}
/*--------------------------------------------------------*/
int main(int argc,char** argv)
{

	struct termios oldtio,newtio;
	int ok;
 	pthread_t th_a, th_b, th_show;//th_a键盘控制；th_b接收信息；th_show显示信息
 	void * retval;
  fd = open(COM3, O_RDWR );//打开串口
	if (fd <0) {
    	perror(COM3);
    	exit(-1);
  	}
  tcgetattr(fd,&oldtio); /* 存储串口设置 */
	newtio.c_cflag = BAUDRATE | CRTSCTS | CS8 | CLOCAL | CREAD;/*控制模式标志.设定bps的速度;硬体流量控制;8位,无校验位,1个终止位;本地连线,只能接收字元*/
	newtio.c_iflag = IGNPAR; /*输入模式标志,IGNPAR忽略奇偶校验位 */
	newtio.c_oflag = 0;		/*输出模式标志.0 Raw模式输出 */
 	newtio.c_lflag = 0;/*0非标准型输入，不回应*/
 	newtio.c_cc[VMIN]=1;/*在读取到1个字元前先停止*/
	newtio.c_cc[VTIME]=0;/*不使用分割字元组的计时器*/
  tcflush(fd, TCIFLUSH);/*清除串口缓冲区*/
	tcsetattr(fd,TCSANOW,&newtio);/*设置串口新参数.TCSANOW常量指定所有的改变将立即生效，	  */
  pthread_create(&th_a, NULL, keyboard, 0);
  pthread_create(&th_b, NULL, receive, 0);
  pthread_create(&th_show, NULL, show_gps_info, 0);
  while(!STOP){
		usleep(100000);
	}	
  pthread_join(th_a, &retval);
  pthread_join(th_b, &retval);
  pthread_join(th_show, &retval);
  tcsetattr(fd,TCSANOW,&oldtio); /* 恢复旧的设置 */
  close(fd);
  	exit(0); 
}