ds18b20采集温度并上报服务器

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交叉编译器：arm-linux-gcc-4.5.4

Linux内核版本：Linux-3.0

主机操作系统：Centos 6.5

开发板：FL2440

温度传感器:ds18b20

注：此程序的客户端是在装有ds18b20模块并有ds18b20驱动的系统上跑的，本人写的ds18b20的驱动

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一、socket图解

socket是“open—write/read—close”模式的一种实现，而在socket编程里面，socket()就是open()函数了。socket编程的流程图示已经很清楚，各个函数的用法这里就懒得说了，也说不好，网上有一堆一堆的专业人士的解释，非专业人士还是直接上代码的比较好。

二、客户端代码：

/*********************************************************************************
 *      Copyright:  (C) 2016 2013dianxin_3
 *                  All rights reserved.
 *
 *       Filename:  mclient.c
 *    Description:  This file 
 *                 
 *        Version:  1.0.0(08/16/2016)
 *         Author:  xiaohexiansheng <1392195453@qq.com>
 *      ChangeLog:  1, Release initial version on "08/16/2016 07:16:44 PM"
 *                 
 ********************************************************************************/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define MAXLINE                 4096
/********************************************************************************
 *  Description:
 *   Input Args:
 *  Output Args:
 * Return Value:
 ********************************************************************************/
double get_tem(void)        //获取温度的函数
{
    int fd;
    double result = 0;
    unsigned char buff[2];
    unsigned short temp = 0;
    int flag = 0;

    if ((fd=open("/dev/ds18b20",O_RDWR | O_NDELAY | O_NOCTTY)) < 0)
    {
        perror("open device ds18b20 failed.
");
        exit(1);
    }

    printf("open device ds18b20 success.
");

    read(fd, buff, sizeof(buff));
    temp=((unsigned short)buff[1])<<8;
    temp|=(unsigned short)buff[0];
    result=0.0625*((double)temp);
    close(fd);
    printf("temperature is %4f 
", result);
    return result;
}

int main (int argc, char **argv)
{
    double      temperature;
    int         sockfd;
    char        temp[25];
    char        sendline[MAXLINE];
    struct sockaddr_in servaddr;
    
    if(argc != 2)        //主函数中需要获得服务器的地址作为第二参数
    {
        printf("usage: ./client <ipaddress>.
");
        return 0;
    }

    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)        //如果打开失败则打印错误并返回
    {
        printf("create socket error: %s(errno: %d).
", strerror(errno), errno);
        return 0;
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(6666);
    if(inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0)        //将点分十进制ip转换为点分二进制ip
    {
        printf("inet_pton error for %s.
", argv[1]);
        return 0;
    }

    if(connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0)        //建立连接
    {
        printf("connect error: %s(errno: %d)
", strerror(errno), errno);
        return 0;
    }

    temperature = get_tem();        //获取温度
    gcvt(temperature, 4, temp);        //将浮点型数转换为字符串
    memset(sendline, 0, sizeof(sendline));
    strcpy(sendline, temp);
    if(send(sockfd, sendline, strlen(sendline), 0) < 0)
    {
        printf("send msg error: %s(errno: %d)
", strerror(errno), errno);
        return 0;
    }

    close(sockfd);
    return 0;
} /* ----- End of main() ----- */

三、服务器端代码

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include <sys/time.h>
#include<time.h>

#define MAXLINE 4096

int main(int argc, char** argv)
{
    int         n;
    int         listenfd;
    int         connfd;
    char        buff[4096];
    struct  sockaddr_in     servaddr;
    
    if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 )        //打开socket，若失败则打印失败信息并返回
    {
        printf("create socket error: %s(errno: %d)
",strerror(errno),errno);
        exit(0);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(6666);

    if(bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1)
    {
        printf("bind socket error: %s(errno: %d)
",strerror(errno),errno);
        exit(0);
    }

    if(listen(listenfd, 10) == -1)        //监听串口
    {
        printf("listen socket error: %s(errno: %d)
",strerror(errno),errno);
        exit(0);
    }

    printf("======waiting for client's request======
");
    while(1)
    {
        memset(buff, 0, sizeof(buff));
        time_t rawtime;
        struct tm* timeinfo;
        char timE[80];
        time(&rawtime);
        timeinfo=localtime(&rawtime);
        strftime(timE,80,"%y-%m-%d %I:%M:%S",timeinfo);        //获取系统时间
        
        if((connfd = accept(listenfd, (struct sockaddr*)NULL, NULL)) == -1)
        {
            printf("accept socket error: %s(errno: %d)",strerror(errno),errno);
            continue;
        }
        n = recv(connfd, buff, MAXLINE, 0);        //从客户端获取数据，并返回数据大小
        strcat(buff, "℃");
        printf("the degrees is: %s %s
", buff, timE);
        close(connfd);
    }
    close(listenfd);
}