This is an example based on mbed-os cellular APIs that demonstrates a TCP or UDP echo transaction with a public echo server.

This code is forked from https://os.mbed.com/teams/mbed-os-examples/code/mbed-os-example-cellular/

This is an example showing how to use Skywire board with LE910-x module.

In this example, I had used the LE910-EUG module for 4G communication. Mbed OS code wasn't changed for LE910-x, because the Telit' HE910 is included mainline code on Mbed OS already. HE910 and LE910 are most similar. Therefore you can use LE910 via HE910 driver. Please check to configure of mbed_app.json, and initialize code for Skywire board of main.cpp.

Open mbed_app.json, you need to define a UART for the MCU to communicate with the xE910 module.

            "TELIT_HE910.tx"                 : "D1",
            "TELIT_HE910.rx"                 : "D0",
            "TELIT_HE910.provide-default"    : true

If you are using Pelion CM, make the following settings:

            "nsapi.default-cellular-apn"     : "\"stream.co.uk\"",
            "nsapi.default-cellular-username": "\"streamip\"",
            "nsapi.default-cellular-password": "\"streamip\"",

For your information, please see Pelion Connectivity Quick start guide.

320

You can find Skywire sensor shield information though NimbeLink site.

Tested with

  • DISCO_L475VG_IOT01A
  • K64F

1. Import the application into your desktop:

 mbed import https://os.mbed.com/users/Daniel_Lee/code/mbed-os-example-cellular-le910/

 cd mbed-os-example-cellular-le910

2. Compile and program:

mbed compile -t GCC_ARM -m DISCO_L475VG_IOT01A

(supported toolchains : GCC_ARM / ARM / IAR)

3. Download binary to a target board

4. Result

mbed-os-example-cellular


Built: Feb  7 2020, 07:02:27
Starting Skywire board with LE910-EUG Demo...
Waiting for Skywire to Boot...
Wait 15 seconds..
Establishing connection


Connection Established.
TCP: connected with echo.mbedcloudtesting.com server
TCP: Sent 4 Bytes to echo.mbedcloudtesting.com
Received from echo server 4 Bytes


Success. Exiting 

main.cpp

Committer:
mbed_official
Date:
2018-03-09
Revision:
2:0f644d6045cf
Parent:
0:4611f6cf2413
Child:
6:5678c0b6f74e

File content as of revision 2:0f644d6045cf:

/*
 * Copyright (c) 2017 ARM Limited. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "mbed.h"
#include "common_functions.h"
#include "UDPSocket.h"
#include "OnboardCellularInterface.h"

#define UDP 0
#define TCP 1

// SIM pin code goes here
#ifndef MBED_CONF_APP_SIM_PIN_CODE
# define MBED_CONF_APP_SIM_PIN_CODE    "1234"
#endif

#ifndef MBED_CONF_APP_APN
# define MBED_CONF_APP_APN         "internet"
#endif
#ifndef MBED_CONF_APP_USERNAME
# define MBED_CONF_APP_USERNAME    NULL
#endif
#ifndef MBED_CONF_APP_PASSWORD
# define MBED_CONF_APP_PASSWORD    NULL
#endif

// Number of retries /
#define RETRY_COUNT 3



// CellularInterface object
OnboardCellularInterface iface;

// Echo server hostname
const char *host_name = "echo.mbedcloudtesting.com";

// Echo server port (same for TCP and UDP)
const int port = 7;

Mutex PrintMutex;
Thread dot_thread(osPriorityNormal, 512);

#define PRINT_TEXT_LENGTH 128
char print_text[PRINT_TEXT_LENGTH];
void print_function(const char *input_string)
{
    PrintMutex.lock();
    printf("%s", input_string);
    fflush(NULL);
    PrintMutex.unlock();
}

void dot_event()
{

    while (true) {
        wait(4);
        if (!iface.is_connected()) {
            print_function(".");
        } else {
            break;
        }
    }

}


/**
 * Connects to the Cellular Network
 */
nsapi_error_t do_connect()
{
    nsapi_error_t retcode;
    uint8_t retry_counter = 0;

    while (!iface.is_connected()) {

        retcode = iface.connect();
        if (retcode == NSAPI_ERROR_AUTH_FAILURE) {
            print_function("\n\nAuthentication Failure. Exiting application\n");
            return retcode;
        } else if (retcode != NSAPI_ERROR_OK) {
            snprintf(print_text, PRINT_TEXT_LENGTH, "\n\nCouldn't connect: %d, will retry\n", retcode);
            print_function(print_text);
            retry_counter++;
            continue;
        } else if (retcode != NSAPI_ERROR_OK && retry_counter > RETRY_COUNT) {
            snprintf(print_text, PRINT_TEXT_LENGTH, "\n\nFatal connection failure: %d\n", retcode);
            print_function(print_text);
            return retcode;
        }

        break;
    }

    print_function("\n\nConnection Established.\n");

    return NSAPI_ERROR_OK;
}

/**
 * Opens a UDP or a TCP socket with the given echo server and performs an echo
 * transaction retrieving current.
 */
nsapi_error_t test_send_recv()
{
    nsapi_size_or_error_t retcode;
#if MBED_CONF_APP_SOCK_TYPE == TCP
    TCPSocket sock;
#else
    UDPSocket sock;
#endif

    retcode = sock.open(&iface);
    if (retcode != NSAPI_ERROR_OK) {
        snprintf(print_text, PRINT_TEXT_LENGTH, "UDPSocket.open() fails, code: %d\n", retcode);
        print_function(print_text);
        return -1;
    }

    SocketAddress sock_addr;
    retcode = iface.gethostbyname(host_name, &sock_addr);
    if (retcode != NSAPI_ERROR_OK) {
        snprintf(print_text, PRINT_TEXT_LENGTH, "Couldn't resolve remote host: %s, code: %d\n", host_name,
               retcode);
        print_function(print_text);
        return -1;
    }

    sock_addr.set_port(port);

    sock.set_timeout(15000);
    int n = 0;
    const char *echo_string = "TEST";
    char recv_buf[4];
#if MBED_CONF_APP_SOCK_TYPE == TCP
    retcode = sock.connect(sock_addr);
    if (retcode < 0) {
        snprintf(print_text, PRINT_TEXT_LENGTH, "TCPSocket.connect() fails, code: %d\n", retcode);
        print_function(print_text);
        return -1;
    } else {
        snprintf(print_text, PRINT_TEXT_LENGTH, "TCP: connected with %s server\n", host_name);
        print_function(print_text);
    }
    retcode = sock.send((void*) echo_string, sizeof(echo_string));
    if (retcode < 0) {
        snprintf(print_text, PRINT_TEXT_LENGTH, "TCPSocket.send() fails, code: %d\n", retcode);
        print_function(print_text);
        return -1;
    } else {
        snprintf(print_text, PRINT_TEXT_LENGTH, "TCP: Sent %d Bytes to %s\n", retcode, host_name);
        print_function(print_text);
    }

    n = sock.recv((void*) recv_buf, sizeof(recv_buf));
#else

    retcode = sock.sendto(sock_addr, (void*) echo_string, sizeof(echo_string));
    if (retcode < 0) {
        snprintf(print_text, PRINT_TEXT_LENGTH, "UDPSocket.sendto() fails, code: %d\n", retcode);
        print_function(print_text);
        return -1;
    } else {
        snprintf(print_text, PRINT_TEXT_LENGTH, "UDP: Sent %d Bytes to %s\n", retcode, host_name);
        print_function(print_text);
    }

    n = sock.recvfrom(&sock_addr, (void*) recv_buf, sizeof(recv_buf));
#endif

    sock.close();

    if (n > 0) {
        snprintf(print_text, PRINT_TEXT_LENGTH, "Received from echo server %d Bytes\n", n);
        print_function(print_text);
        return 0;
    }

    return -1;
}

int main()
{

    iface.modem_debug_on(MBED_CONF_APP_MODEM_TRACE);
    /* Set Pin code for SIM card */
    iface.set_sim_pin(MBED_CONF_APP_SIM_PIN_CODE);

    /* Set network credentials here, e.g., APN*/
    iface.set_credentials(MBED_CONF_APP_APN, MBED_CONF_APP_USERNAME, MBED_CONF_APP_PASSWORD);

    print_function("\n\nmbed-os-example-cellular\n");
    print_function("Establishing connection ");
    dot_thread.start(dot_event);

    /* Attempt to connect to a cellular network */
    if (do_connect() == NSAPI_ERROR_OK) {
        nsapi_error_t retcode = test_send_recv();
        if (retcode == NSAPI_ERROR_OK) {
            print_function("\n\nSuccess. Exiting \n\n");
            return 0;
        }
    }

    print_function("\n\nFailure. Exiting \n\n");
    return -1;
}
// EOF