GSM/GPRS/3G/4G

1、状态机机制的gprs拨号

像GPRS/3G模块之类的应用，需要连接，登陆，初始化等步骤完成后才能传输数据，而这些步骤又比较耗时。

所以用状态机 + 超时的机制来实现比较合理。

如下代码片段来描述数据透传：状态机 + 超时这种机制（代码片段，仅用来描述一种思路）

以下程序是在没有操作系统调度机制下调试的，所以超时用的心跳，如果是linux下，有sleep更方便。

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#define SERVER_IP "115.29.140.xxx"

#define SERVER_PORT   "8082"

#define BUFF_LEN 64

char aUart5RxBuffer[BUFF_LEN];

static int gprs_init_ok= ;

static int ppp_config_ok = ;

void gprs_init(void)

{

    if((strstr(aUart5RxBuffer, "command ready") == NULL)

        /*||(strstr(aUart5RxBuffer, "+SIM READY") == NULL)*/)

    {

         gprs_init_ok = ;

    }

    else

    {

         gprs_init_ok = ;

    } 

}

void reset_gprs(void)

{

    memset(aUart5RxBuffer, , BUFF_LEN);

    gprs_init_ok= ;

    ppp_config_ok = ;

    //reset 3g module;

}

void ppp_config(void)

{

    static uint32_t ppp_config_step = ;

    static uint32_t gprs_tick = ;

    switch (ppp_config_step)

    {

        case :

            gprs_puts("AT+GTSET=\"LPMMODE\",0\r\n");

            gprs_tick = msTicks;

            ppp_config_step = ;

            break;

        case :

            if((msTicks - gprs_tick) > )

            {

                if(strstr(aUart5RxBuffer, "OK") == NULL)

                {

                    ppp_config_step = ;

                }

                else

                {

                    ppp_config_step = ; 

                }

                memset(aUart5RxBuffer, , BUFF_LEN);

            }

            break;

        case :

            gprs_puts("AT+CPIN?\r\n");

            ppp_config_step = ;

            gprs_tick = msTicks;

            break;

        case :

            if((msTicks - gprs_tick) > )

            {

                if((strstr(aUart5RxBuffer, "OK") == NULL) || (strstr(aUart5RxBuffer, "+CPIN: READY") == NULL))

                {

                    ppp_config_step = ;

                }

                else

               {

                ppp_config_step = ;

               }

               memset(aUart5RxBuffer, , BUFF_LEN);

            }

            break;          

        case :

            gprs_puts("AT+CSQ\r\n");

            ppp_config_step = ;

            gprs_tick = msTicks;

            break;

        case :

            if((msTicks - gprs_tick) > )

            {

                if(strstr(aUart5RxBuffer, "OK") == NULL)

                {

                    ppp_config_step = ;

                }

                else

                {

                    ppp_config_step = ;

                }

                memset(aUart5RxBuffer, , BUFF_LEN);

            }

            break;

        case :

            gprs_puts("AT+CREG?\r\n");

            ppp_config_step = ;

            gprs_tick = msTicks;

            break;

        case :

            if((msTicks - gprs_tick) > )

            {

                if(strstr(aUart5RxBuffer, "+CREG: 0,0") == NULL)

                {

                    ppp_config_step = ;

                }

                else

                {

                    ppp_config_step = ;

                }

                memset(aUart5RxBuffer, , BUFF_LEN);

            }

            break;

        case :

            //gprs_puts("AT+MIPCALL=1,\"3GNET\"\r\n");

            gprs_puts("AT+MIPCALL=1,\"xagfzqx.ydoa.snapn\"\r\n");

            ppp_config_step = ;

            gprs_tick = msTicks;

            break;

        case :

            if((msTicks - gprs_tick) > )

            {

                if(strstr(aUart5RxBuffer, "+MIPCALL: 0") == NULL)

                {

                    ppp_config_step = ;

                    ppp_config_ok = ;

                }

                else

                {

                    ppp_config_step = ;

                }

                memset(aUart5RxBuffer, , BUFF_LEN);

            }

            break;             

        default:

            break;

    }    

}

void http_Send_test(char *data)

{

    static unsigned char http_send_step = ;

    static int send_err_cnt = ;

    switch (http_send_step)

    {

    case :

        memset(data_tx_buf, , sizeof(data_tx_buf));

        strcat(data_tx_buf, data);

        gprs_puts("GET /app/pulse-wave/commit?");

        gprs_puts("%s",data_tx_buf);

        gprs_puts("\r\n");    

        http_send_step = ;

        gprs_tick = msTicks;

        break;

    case :

        if((strstr(aUart5RxBuffer, "{\"msg\":\"commit pulse-wave data success.\",\"result\":true}") != NULL)

            &&(strstr(aUart5RxBuffer, "+MIPSTAT: 1,1") != NULL)

            &&((msTicks - gprs_tick) < ))

        { 

        }

        else

        {

            if(++send_err_cnt > ) {

                reset_gprs();

                send_err_cnt = ;

            } 

        }

　　　　　memset(aUart5RxBuffer, 0, BUFF_LEN);

        http_send_step = ;              

        break;                                              

    default:

        break;

    }

}

void main(void)

{

    while()

    {

       if(!gprs_init_ok)                        { gprs_init(); }

       if((gprs_init_ok)&&(!ppp_config_ok))     { ppp_config(); } 

       if(ppp_config_ok)                        { http_Send_test("hello,world"); }

    }

}

初始化成功了就可以传输数据了，数据发送和接收都跟串口一样。主要工作都在初始化，和异常修复机制的实现。因为网络传输每一步都可能会失败，而且外部因素太多，所以异常修复机制尤其重要。

2、用开源的ppp/pppoe指令拨号也一样

ppp

https://download.samba.org/pub/ppp/

pppoe

https://www.roaringpenguin.com/products/pppoe

eg:

https://blog.csdn.net/a746742897/article/details/52421461

1) 3g

https://blog.csdn.net/qq_21792169/article/details/51271833

https://blog.csdn.net/yangzheng_yz/article/details/9315287

2) 4g