This is an example based on mbed-os cellular APIs that demonstrates a TCP or UDP echo transaction with a public echo server. Especially, BG96 operation check based Mbed OS 5.11, tested via SK Telecom in Korea

This code could be access via Cat.M1(BG96 module) of SK telecom network in Korea. Need a WIZnet BG96 board and development board. Before using this code, must be checking your modem is authorized or not from SK telecom. This code is based on Mbed OS 5.11.5.

/media/uploads/Daniel_Lee/img_8560.jpg

Tested with

  • DISCOVERY_L485VG_IOT01A
  • K66F
  • K64F

1. Import the application into your desktop

 mbed import https://os.mbed.com/users/Daniel_Lee/code/mbed-os-example-cellular-BG96_os511/

 cd mbed-os-example-cellular-BG96_os511

2. Compile and program

mbed compile -t <toolchain> -m <TARGET_BOARD>

(supported toolchains : GCC_ARM / ARM / IAR)

3. Download binary to a target board

4. Result

mbed-os-example-cellular


Built: Jun  4 2019, 13:45:53


[MAIN], plmn: (null)
Modem power on
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

5. Patched code

If need more information such as how to test, please look at https://os.mbed.com/teams/mbed-os-examples/code/mbed-os-example-cellular/.

main.cpp

Committer:
mbed_official
Date:
2018-11-23
Revision:
28:232da3ce8a88
Parent:
27:97054be1a741
Child:
34:6f85d44597ac

File content as of revision 28:232da3ce8a88:

/*
 * 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 "CellularLog.h"

#define UDP 0
#define TCP 1

// 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 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) {
#if MBED_CONF_APP_SOCK_TYPE == TCP
        print_function("TCPSocket.open() fails, code: %d\n", retcode);
#else
        print_function("UDPSocket.open() fails, code: %d\n", retcode);
#endif
        return -1;
    }

    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);

    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) {
        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, sizeof(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, sizeof(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

    sock.close();

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

    return -1;
}

int main()
{
    print_function("\n\nmbed-os-example-cellular\n");
    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

    // sim pin, apn, credentials and possible plmn are taken atuomtically from json when using get_default_instance()
    iface = NetworkInterface::get_default_instance();
    MBED_ASSERT(iface);

    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