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:
Daniel_Lee
Date:
2020-02-07
Revision:
51:8d0212a4b805
Parent:
42:cab443dff75e

File content as of revision 51:8d0212a4b805:

/*
 * 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 "CellularNonIPSocket.h"
#include "CellularDevice.h"
#include "UDPSocket.h"
#include "CellularLog.h"

#define UDP 0
#define TCP 1
#define NONIP 2

// Number of retries /
#define RETRY_COUNT 3

NetworkInterface *iface;

// Echo server hostname
const char *host_name = MBED_CONF_APP_ECHO_SERVER_HOSTNAME;

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

static rtos::Mutex trace_mutex;

#if MBED_CONF_MBED_TRACE_ENABLE
static void trace_wait()
{
    trace_mutex.lock();
}

static void trace_release()
{
    trace_mutex.unlock();
}

static char time_st[50];

static char* trace_time(size_t ss)
{
    snprintf(time_st, 49, "[%08llums]", Kernel::get_ms_count());
    return time_st;
}

static void trace_open()
{
    mbed_trace_init();
    mbed_trace_prefix_function_set( &trace_time );

    mbed_trace_mutex_wait_function_set(trace_wait);
    mbed_trace_mutex_release_function_set(trace_release);

    mbed_cellular_trace::mutex_wait_function_set(trace_wait);
    mbed_cellular_trace::mutex_release_function_set(trace_release);
}

static void trace_close()
{
    mbed_cellular_trace::mutex_wait_function_set(NULL);
    mbed_cellular_trace::mutex_release_function_set(NULL);

    mbed_trace_free();
}
#endif // #if MBED_CONF_MBED_TRACE_ENABLE

Thread dot_thread(osPriorityNormal, 512);

void print_function(const char *format, ...)
{
    trace_mutex.lock();
    va_list arglist;
    va_start( arglist, format );
    vprintf(format, arglist);
    va_end( arglist );
    trace_mutex.unlock();
}

void dot_event()
{
    while (true) {
        ThisThread::sleep_for(4000);
        if (iface && iface->get_connection_status() == NSAPI_STATUS_GLOBAL_UP) {
            break;
        } else {
            trace_mutex.lock();
            printf(".");
            fflush(stdout);
            trace_mutex.unlock();
        }
    }
}

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

    while (iface->get_connection_status() != NSAPI_STATUS_GLOBAL_UP) {
        retcode = iface->connect();
        if (retcode == NSAPI_ERROR_AUTH_FAILURE) {
            print_function("\n\nAuthentication Failure. Exiting application\n");
        } else if (retcode == NSAPI_ERROR_OK) {
            print_function("\n\nConnection Established.\n");
        } else if (retry_counter > RETRY_COUNT) {
            print_function("\n\nFatal connection failure: %d\n", retcode);
        } else {
            print_function("\n\nCouldn't connect: %d, will retry\n", retcode);
            retry_counter++;
            continue;
        }
        break;
    }
    return retcode;
}

/**
 * Opens:
 * - UDP or TCP socket with the given echo server and performs an echo
 *   transaction retrieving current.
 * - Cellular Non-IP socket for which the data delivery path is decided
 *   by network's control plane CIoT optimisation setup, for the given APN.
 */
nsapi_error_t test_send_recv()
{
    nsapi_size_or_error_t retcode;
#if MBED_CONF_APP_SOCK_TYPE == TCP
    TCPSocket sock;
#elif MBED_CONF_APP_SOCK_TYPE == UDP
    UDPSocket sock;
#elif MBED_CONF_APP_SOCK_TYPE == NONIP
    CellularNonIPSocket sock;
#endif

#if MBED_CONF_APP_SOCK_TYPE == NONIP
    retcode = sock.open((CellularContext*)iface);
#else
    retcode = sock.open(iface);
#endif

    if (retcode != NSAPI_ERROR_OK) {
#if MBED_CONF_APP_SOCK_TYPE == TCP
        print_function("TCPSocket.open() fails, code: %d\n", retcode);
#elif MBED_CONF_APP_SOCK_TYPE == UDP
        print_function("UDPSocket.open() fails, code: %d\n", retcode);
#elif MBED_CONF_APP_SOCK_TYPE == NONIP
        print_function("CellularNonIPSocket.open() fails, code: %d\n", retcode);
#endif
        return -1;
    }

    int n = 0;
    const char *echo_string = "TEST";
    char recv_buf[4];

    sock.set_timeout(15000);

#if MBED_CONF_APP_SOCK_TYPE == NONIP
    retcode = sock.send((void*) echo_string, strlen(echo_string));
    if (retcode < 0) {
        print_function("CellularNonIPSocket.send() fails, code: %d\n", retcode);
        return -1;
    } else {
        print_function("CellularNonIPSocket: Sent %d Bytes\n", retcode);
    }

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

#else

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

    sock_addr.set_port(port);

#if MBED_CONF_APP_SOCK_TYPE == TCP
    retcode = sock.connect(sock_addr);
    if (retcode < 0) {
        print_function("TCPSocket.connect() fails, code: %d\n", retcode);
        return -1;
    } else {
        print_function("TCP: connected with %s server\n", host_name);
    }
    retcode = sock.send((void*) echo_string, strlen(echo_string));
    if (retcode < 0) {
        print_function("TCPSocket.send() fails, code: %d\n", retcode);
        return -1;
    } else {
        print_function("TCP: Sent %d Bytes to %s\n", retcode, host_name);
    }

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

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

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

    sock.close();

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

    return -1;
}

void init_SkyWire4G()
{
    DigitalOut myled(LED1);                             // Main LED
    DigitalOut skywire_en(D12);                        // Skywire Enable
    DigitalOut skywire_rts(D11);                       // Skywire Send
    DigitalOut green_LED(A1);                         // Green LED
    DigitalOut red_LED(A2);                           // Red LED
    DigitalOut blue_LED(A3);                          // Blue LED

    AnalogIn photo_trans(A0);                         // Photo Transistor
    AnalogIn pot(A5);                                 // Potentiometer
    DigitalIn button1(D3);                            // Button 1
    DigitalIn button2(A4);                            // Button 2
#if 0
    I2C i2c(D14,D15);                                 // Setup I2C bus for sensors

    LPS331 pressure(i2c);                               // Pressure Sensor
    LM75B LM75_temp(D14,D15);                         // Temp Sensor
    // Accelerometer
    LIS3DH accel(i2c, LIS3DH_V_CHIP_ADDR, LIS3DH_DR_NR_LP_100HZ, LIS3DH_FS_2G);
    HTS221 humidity(D14, D15);                        // Humidity Sensor
#endif

    // Turn on blue LED
    green_LED = 0;
    red_LED = 0;
    blue_LED = 1;

    skywire_rts=0;
    myled=0;
    printf("Starting Skywire board with LE910-EUG Demo...\n");
    printf("Waiting for Skywire to Boot...\n");

    //Enable Skywire
    skywire_en=0;
    ThisThread::sleep_for(2000);
    skywire_en=1;
    ThisThread::sleep_for(2000);
    skywire_en=0;

    myled=1;
        
    printf("Wait 15 seconds..\n");
    ThisThread::sleep_for(15000);
}


int main()
{
    print_function("\n\nmbed-os-example-cellular\n");
    print_function("\n\nBuilt: %s, %s\n", __DATE__, __TIME__);
#ifdef MBED_CONF_NSAPI_DEFAULT_CELLULAR_PLMN
    print_function("\n\n[MAIN], plmn: %s\n", (MBED_CONF_NSAPI_DEFAULT_CELLULAR_PLMN ? MBED_CONF_NSAPI_DEFAULT_CELLULAR_PLMN : "NULL"));
#endif

    init_SkyWire4G();
    print_function("Establishing connection\n");
#if MBED_CONF_MBED_TRACE_ENABLE
    trace_open();
#else
    dot_thread.start(dot_event);
#endif // #if MBED_CONF_MBED_TRACE_ENABLE

#if MBED_CONF_APP_SOCK_TYPE == NONIP
    iface = CellularContext::get_default_nonip_instance();
#else
    iface = CellularContext::get_default_instance();
#endif

    MBED_ASSERT(iface);

    // sim pin, apn, credentials and possible plmn are taken automatically from json when using NetworkInterface::set_default_parameters()
    iface->set_default_parameters();

    nsapi_error_t retcode = NSAPI_ERROR_NO_CONNECTION;

    /* Attempt to connect to a cellular network */
    if (do_connect() == NSAPI_ERROR_OK) {
        retcode = test_send_recv();
    }

    if (iface->disconnect() != NSAPI_ERROR_OK) {
        print_function("\n\n disconnect failed.\n\n");
    }

    if (retcode == NSAPI_ERROR_OK) {
        print_function("\n\nSuccess. Exiting \n\n");
    } else {
        print_function("\n\nFailure. Exiting \n\n");
    }

#if MBED_CONF_MBED_TRACE_ENABLE
    trace_close();
#else
    dot_thread.terminate();
#endif // #if MBED_CONF_MBED_TRACE_ENABLE

    return 0;
}
// EOF