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导航制导与控制实验室 2014年11月10日

好久没有写博客了，先从一个小小的程序開始一段新的历程吧。

近期的项目主要还是用的的是linux系统，这篇文章主要介绍怎样从设置、读取BD+gps模块（um220），实际上主要是对串口（UART）的操作。

/*

 * gps.c

 *

 * um220 test

 *

 * Author: Wang Zhengkai <449811900@qq.com>

 *

 */

#include <stdio.h>

#include <termios.h>

#include <strings.h>

#include <string.h>

#include <stdlib.h>

#include <fcntl.h>

#include <unistd.h>

/*我用的是ubuntu的电脑測试的，使用的串口是ttyS0*/

#define DEV_NODE "/dev/ttyS0"

#define MAX_PACKET_SIZE 1024

</pre><pre code_snippet_id="478189" snippet_file_name="blog_20140930_2_1496439" name="code" class="objc">/************************************************

******* Initialize serial port options***********

************************************************/

static void setTermios(struct termios * pNewtio, int uBaudRate)

{

	bzero(pNewtio, sizeof(struct termios)); /* clear struct for new port settings */

	//8N1

	pNewtio->c_cflag = uBaudRate | CS8 | CREAD | CLOCAL;

	pNewtio->c_iflag = IGNPAR;

	pNewtio->c_oflag = 0;

	pNewtio->c_lflag = 0; //non ICANON

}

/*************************************************

**设置um220串口的波特率9600。并刷新使其马上生效***

**************************************************/

void um220_uart_init(int ttyFd,struct termios *oldtio,struct termios *newtio)

{

	tcgetattr(ttyFd, oldtio); /* save current serial port settings */

	setTermios(newtio, B9600);

	tcflush(ttyFd, TCIFLUSH);

	tcsetattr(ttyFd, TCSANOW, newtio);

}

/**************************************************

*************Analysis Data of um220****************

***************************************************/

void parseData(char *buf)

{

	int nQ, nN, nB, nC;

	char cX, cY, cM1, cM2;

	float fTime, fX, fY, fP, fH, fB, fD;

	if (buf == NULL)

	{

		printf("error: Can't get buf!\n");

		return;

	}

	sscanf(buf,"$GNGGA,%f,%f,%c,%f,%c,%d,%02d,%f,%f,%c,%f,%c,%f,%04d%02x",&fTime,&fX,&cX,&fY,&cY,&nQ,&nN,&fP,&fH,&cM1,&fB,&cM2, &fD, &nB, &nC);

	printf("x: %c %f, y: %c %f, h %f, satellite: %d\n",cX, fX, cY, fY, fH, nN);

/*cX：N or S;fX：纬度；cY：E or W；fY：经度；fH：height；nN：卫星个数*/

}

int main(void)

{

	int nb,command;

	int um220_fd = -1;

	char newbuf[MAX_PACKET_SIZE];

	char msg[20],*ret=NULL;

	struct termios oldtio, newtio;

	/*Open Um220 Module*/

	if ((um220_fd = open(DEV_NODE, O_RDWR)) < 0) {

		printf("error: Can't open serial port %s!\n", DEV_NODE);

                return -1;

        }

	/*Init Uart for Um220*/

	um220_uart_init(um220_fd,&oldtio,&newtio);

	/*Set Um220 options*/

	printf("Please select modules of um220\n");

	printf("1.BD module\n");

	printf("2.GPS module\n");

	printf("3.BD+GPS module\n");

	if(scanf("%d",&command) != 1)

	{

		printf("error:input is wrong!\n");

	}

	switch(command)

	{

		case 1:

			memset(msg, 0, sizeof(msg));

			strcpy(msg,"$cfgsys,h01");

			if(write(um220_fd,msg,sizeof(msg)) < 0)

			printf("Failed to set BD modules!\n");

			break;

		case 2:

			memset(msg, 0, sizeof(msg));

			strcpy(msg,"$cfgsys,h10");

			if(write(um220_fd,msg,sizeof(msg)) < 0)

			printf("Failed to set GPS modules!\n");

			break;

		case 3:

			memset(msg, 0, sizeof(msg));

			strcpy(msg,"$cfgsys,h11");

			if(write(um220_fd,msg,sizeof(msg)) < 0)

			printf("Failed to set BD+GPS modules!\n");

			break;

		default:

			printf("Can't identify command,set BD+GPS modules!\n");

			memset(msg, 0, sizeof(msg));

			strcpy(msg,"$cfgsys,h11");

			if(write(um220_fd,msg,sizeof(msg)) < 0)

			printf("Failed to set BD+GPS modules!\n");

	}

	for(;;)

	{

	/*Read Data from Um220*/

	memset(newbuf, 0, 1024);

	nb = read(um220_fd, newbuf, MAX_PACKET_SIZE);

        if (nb == -1)

		{

                perror("read uart error");

		return -1;

		}

	if ((ret=strstr(newbuf, "$GNGGA")) != NULL)

		{

	/*Analysis Data*/

		parseData(ret);

		}

	sleep(1);

	}

	/*Recover Settings Of Serial Port*/

	tcsetattr(um220_fd,TCSANOW,&oldtio);

	/*Close Um220_fd*/

	close(um220_fd);

	return 0;

}