linux下GPRS模塊的應用程序

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交叉編譯器：arm-linux-gcc-4.5.4

Linux內核版本：Linux-3.0

主機操作系統：Centos 6.5

開發板：FL2440

GPRS:SIM900A

在開發SIM900模塊之前，開發板已經加載了linux內核以及文件系統，並且開發板串口已經使能。並且一定要注意的是：要有一張沒有欠費的電話卡！

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參考文檔

http://www.cnblogs.com/thinkinglife/p/3986006.html

 

一、GPRS模塊簡介

GPRS模塊，是具有GPRS數據傳輸功能的GSM模塊。GPRS模塊就是一個精簡版的手機，集成GSM通信的主要功能於一塊電路板上，具有發送短消息、通話、數據傳輸等功能。GPRS模塊相當於手機的核心部分，如果增加鍵盤和屏幕就是一個完整的手機。普通電腦或者單片機可以通過RS232串口與GPRS模塊相連，通過AT指令控制GPRS模塊實現各種基於GSM的通信功能。 制作串口線將  GPRS模塊的串口和開發板的串口連接起來（我連接的是開發的第二個串口，因為第一個串口連接PC了）。

 

二、打開GPRS模塊

這個地方介紹GPRS的打開方式看起來有些傻逼，不過第一次拿到GPRS模塊並且沒有任何人指導的情況下可能真的不會打開。

首先插上手機卡，必須是以前的大卡，如果是小卡的話也可以，需要對准之后放上去才能工作。然后撥動GPRS模塊的撥碼開關，在GPRS模塊的最下方，一個很明顯很大的撥碼開關。最后在撥碼開關的左上方有一個黑色的小按鈕SW1，按下按鈕讓讓SIM開始工作，搜索網絡這時發光二極管D3會閃爍。

 

三、AT命令 

GPRS模塊在Linux環境下操作不需要移植任何東西，只需要在Linux下用AT命令通過串口讀取、寫入信息就可以實現對GPRS模塊的操作。AT命令的使用方法網上有許多，這里就不一一解釋了，沒有太多意義。只簡單的介紹一下打電話發短信必要的命令就可以了。

以下都是在開發板上的操作：

#microcom -t 15000 -s 115200 /dev/ttyS0　　　　　　//linux下的串口調試軟件microcom

-t 單位毫秒，無操作自動退出時間。

ttyS0 要操作的串口。

接下來的命令都是往串口中寫的了。

AT　　　　//檢測串口是否OK，若返回OK表示是可以用的

打電話：

atd***********;　　　　//后面的***********是電話號碼，【注意】“；”一定要有

ath　　　　//掛斷電話

當有電話來時，串口會打印RING。如果GPRS模塊上插有耳機，可以聽到提示來電的聲音。

ata　　　　//接通電話

ath　　　　//掛斷電話

發短信：

AT+CMGF=1　　　　//選擇短消息格式 1對應文本格式 0對應PDU模式,支持中文,中文短信發送時候需要轉碼。

AT+CMGS="GSM"　　　　//設置字符格式為GSM模式,可不用設置

at+cmgs="***********"　　　　//***********是11位手機號

輸入之后回車顯示一個 >  提示輸入文本,這個時候輸入文本。注意：輸入文本完畢之后不敲回車而是敲ctrl+z表示輸入完畢。

接受短信：

AT+CNMI=3,2　　　　//設置GPRS為來短信提示新短信狀態

 

三、C程序實現打電話發短信接電話收短信功能

開始的時候寫了兩個程序：一個是打電話發短信的，一個是接電話接短信的。因為這兩個程序不能同時運行，所以后來想要整合在一起的時候一直想的是用雙線程或雙進程，每個進程各自運行一個程序。后來想模仿手機打電話的功能：一般我們的手機都是處於接電話與接短信的狀態，如果手機想要打電話或者發短信則按相應按鍵進入相應函數。那么我的程序也可以這樣實現，讓程序一直跑在接電話與接短信的狀態，一旦鍵盤上有想要打電話與發短信的輸入則進入打電話發短信的函數。

/*********************************************************************************
 *      Copyright:  (C) 2016 2013dianxin_3
 *                  All rights reserved.
 *
 *       Filename:  kbhit.c
 *    Description:  This file 
 *                 
 *        Version:  1.0.0(08/04/2016)
 *         Author:  xiaohexiansheng <[e-mail]>
 *      ChangeLog:  1, Release initial version on "08/04/2016 01:23:17 PM"
 *                 
 ********************************************************************************/
#include <termios.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <termios.h>
#include <unistd.h>
#include <fcntl.h>

#define len_message 128
#define len_number 16
#define len_swap 32

//信息結構體，包括號碼和信息
struct message_info                
{
    char phnu[len_number];
    char message[len_message];
};

//初始化串口
void serial_init(int fd)        
{
    struct termios options;
    tcgetattr(fd, &options);
    options.c_cflag |= (CLOCAL | CREAD);
    options.c_cflag &= ~CSIZE;
    options.c_cflag &= ~CRTSCTS;
    options.c_cflag |= CS8;
    options.c_cflag &= ~CSTOPB;
    options.c_iflag |= IGNPAR;
    options.c_oflag  = 0;
    options.c_lflag  = 0;

    cfsetispeed(&options, B115200);                //根據自己的波特率進行相應更改
    cfsetospeed(&options, B115200);
    tcsetattr(fd, TCSANOW, &options);
};

//非阻塞判斷函數，用於判斷鍵盤上有沒有輸入
int kbhit(void)                    
{
    struct termios oldt, newt;
    int ch;
    int oldf;
    tcgetattr(STDIN_FILENO, &oldt);
    newt = oldt;
    newt.c_lflag &= ~(ICANON | ECHO);
    tcsetattr(STDIN_FILENO, TCSANOW, &newt);
    oldf = fcntl(STDIN_FILENO, F_GETFL, 0);
    fcntl(STDIN_FILENO, F_SETFL, oldf | O_NONBLOCK);
    ch = getchar();
    tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
    fcntl(STDIN_FILENO, F_SETFL, oldf);
    if(ch != EOF)
    {
        ungetc(ch, stdin);
        return 1;
    }
    return 0;
}


//發短信的函數
int send(int fd, char *cmgf, char *cmgs, char *message)            
{
    int nwrite;
    int nread;
    char buff[len_message];            //用於向串口中寫數據的buff
    char replay[len_message];        //用於讀串口中數據的buff

    memset(buff, 0, len_message);
    strcpy(buff, "AT\r");
    nwrite = write(fd, buff, strlen(buff));        //將buff中的數據寫入串口
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_message);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));    //讀取串口中的數據到replay
    printf("nread = %d, %s\n", nread, replay);

    memset(buff, 0, len_message);
    strcpy(buff, "AT+CMGF=");
    strcat(buff, cmgf);
    strcpy(buff, "\r");
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_message);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));
    printf("nread = %d, %s\n", nread, replay);

    memset(buff, 0, len_message);
    strcpy(buff, "AT+CMGS=");
    strcat(buff, cmgs);
    strcat(buff, "\r");
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_message);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));
    printf("nread = %d, %s\n", nread, replay);

    memset(buff, 0, len_message);
    strcpy(buff, message);
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_message);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));
    printf("nread = %d, %s\n", nread, replay);
    
    return 0;
}

int send_en_message()
{
    int fd;
    struct message_info info;
    fd = open("/dev/ttyS1",O_RDWR|O_NOCTTY|O_NDELAY);
    
    if(fd < 0)
    {
        perror("Can not open ttyS1!\n");
    }
    getchar();                        //讀取緩沖區中的一個回車，不然下面讀取緩沖區數據的時候會出錯
    char cmgf[] = "1";
    char cmgs[16] = {'\0'};
    int conter = 0;

    printf("Please enter your number:\n");
    fgets(info.phnu, (len_number-1), stdin);
    while(strlen(info.phnu) != 12)
    {
        if(conter == 3)
        {
            printf("contr out!\n");
            return -1;
        }
        printf("Your number is not standard,please enter again.\n");
        fgets(info.phnu, (len_number - 1), stdin);
        conter++;
    }
    printf("Enter your message:\n");
    fgets(info.message, (len_message), stdin);
    strcat(info.message, "\x1a");
    strcat(cmgs, "\"");
    strcat(cmgs, info.phnu);
    cmgs[12] = (char){'\"'};

    send(fd, cmgf, cmgs, info.message);
    close(fd);

    return 0;
}

void send_ch_message()                    //這里沒有支持發送中文短信
{
    printf("send_ch_message.\n");
}

int call(int fd, char *atd)
{
    int nread;
    int nwrite;
    char buff[len_message];
    char replay[len_message];

    memset(buff, 0, len_message);
    strcpy(buff, "at\r");
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_message);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));
    printf("nread = %d, %s\n", nread, replay);

    memset(buff, 0, strlen(buff));
    strcpy(buff, "atd");
    strcat(buff, atd);
    strcat(buff, "\r");
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_message);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));
    printf("nread = %d, %s\n", nread, replay);

    printf("Enter 4 to Hang up!\n");
    char choice = getchar();
    getchar();
    switch(choice)
    {
        case'4':
            memset(buff, 0, len_number);
            strcpy(buff, "ath\r");
            nwrite = write(fd, buff, strlen(buff));
            printf("nwrite = %d, %s\n", nwrite, buff);

            memset(replay, 0, len_number);
            sleep(1);
            nread = read(fd, replay, sizeof(replay));
            printf("nread = %d, %s\n", nread, replay);
        default:
            break;
    }
    return 0;
}

//打電話的函數
int call_phone()
{
    int fd;
    int conter = 0;
    char atd[16] = {'\0'};
    struct message_info info;

    fd = open("/dev/ttyS1",O_RDWR|O_NOCTTY|O_NDELAY);
    {
        perror("Can not open ttyS1!\n");
    }

    getchar();
    printf("Enter your phonenumber:\n");
    fgets(info.phnu, (len_number - 1), stdin);
    while(strlen(info.phnu) != 12)
    {
        if(conter == 3)
        {
            printf("conter out!\n");
            return -1;
        }
        printf("Your number is not standard,please enter again.\n");
        fgets(info.phnu, (len_number - 1), stdin);
        conter++;
    }
    strcat(atd, info.phnu);
    atd[11] = (char){';'};
    call(fd, atd);
    close(fd);
    return 0;
}

//來電時拒接電話的函數
int refuse(int fd)
{
    int nwrite;
    int nread;
    char buff[len_number];
    char replay[len_number];

    getchar();
    memset(buff, 0, len_number);
    strcpy(buff, "ath\r");
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_number);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));
    printf("nread = %d, %s\n", nread, replay);

    return 0;
}

//來電時接電話的函數
int receive(int fd)
{
    char replay[len_number];
    char buff[len_number];
    int nwrite;
    int nread;
    int choice;

    getchar();
    memset(buff, 0, len_number);
    strcpy(buff, "ata\r");
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    memset(replay, 0, len_number);
    sleep(1);
    nread = read(fd, replay, sizeof(replay));
    printf("nread = %d, %s\n", nread, replay);

    printf("Enter 4 to Hang up!\n");
    choice = getchar();
    getchar();
    switch(choice)
    {
        case'4':
            memset(buff, 0, len_number);
            strcpy(buff, "ath\r");
            nwrite = write(fd, buff, strlen(buff));
            printf("nwrite = %d, %s\n", nwrite, buff);

            memset(replay, 0, len_number);
            sleep(1);
            nread = read(fd, replay, sizeof(replay));
            printf("nread = %d, %s\n", nread, replay);
        default:
            break;
    }
    return 0;
}

//等待電話來的函數
int waitphone(void)
{
    int i = 4;
    int fd;
    int choice;
    int nwrite;
    int nread;
    char replay[len_number];
    char str[] = "\n\nRING";
    char buff[len_number];

    fd = open("/dev/ttyS1",O_RDWR|O_NOCTTY|O_NDELAY);
    if(fd < 0)
    {
        perror("Can not open ttyS1!\n");
    }

    serial_init(fd);
    memset(buff, 0, len_number);
    strcpy(buff, "at\r");
    nwrite = write(fd, buff, strlen(buff));
    printf("nwrite = %d, %s\n", nwrite, buff);

    while(i)
    {
        memset(replay, 0, len_number);
        sleep(1);
        nread = read(fd, replay, sizeof(replay));
        printf("nread = %d, %s\n", nread, replay);

        memset(replay, 0, len_number);
        sleep(2);
        nread = read(fd, replay, sizeof(replay));
        if(!(strncmp(replay, str, 6)))
        {
            printf("there is a ring.\n");
            printf("1.to receive.\n");
            printf("2.to refuse.\n");

            choice = getchar();
            switch(choice)
            {
                case'1':
                    receive(fd);
                    break;
                case'2':
                    refuse(fd);
                    break;
                default:
                    break;
            }
        }
        i--;
    }
    close(fd);
    return 0;
}

//設置為來短信提示狀態
int message(void)
{
    int fd;
    int nwrite;
    char buff[len_number];
    char replay[len_message];

    fd = open("/dev/ttyS1",O_RDWR|O_NOCTTY|O_NDELAY);
    if(fd < 0)
    {
        perror("Can not open ttyS1!\n");
    }
    serial_init(fd);
    memset(buff, 0, len_number);
    strcpy(buff, "AT+CNMI=3,2\r");
    nwrite = write(fd, buff, strlen(buff));
    sleep(1);
    memset(replay, 0, len_message);
    read(fd, replay, sizeof(replay));
    close(fd);
}

int main(void)
{
    printf("Please enter your choice:\n");
    printf("1:for english message.\n");
    printf("2:for chinese message.\n");
    printf("3:for a call.\n");
    printf("enter nothing for a waiting.\n");
    message();
    while(1)
    {
//如果鍵盤沒有輸入，則一直處在等待接電話的狀態中
//一旦鍵盤有輸入則讀取鍵盤輸入並判斷是打電話還是發短信
        while(!kbhit())
        {
            waitphone();
            sleep(1);
        }
        char choice = getchar();        //一旦鍵盤有輸入則接收鍵盤輸入並根據輸入選擇進入某個函數。
        switch(choice)
        {
            case'1':
                send_en_message();
                break;
            case'2':
                send_ch_message();
                break;
            case'3':
                call_phone();
                break;
            default:
                break;
        }
    }
    return 0;
}