This is an example based on mbed-os cellular APIs that demonstrates a TCP or UDP echo transaction with a public echo server. Included TPB23 NB-IoT module which is can use LGU+ in Korea.

This example is showing how to use the NB-IoT(SECOM TPB23 module) of LGU plus network in Korea. The NB-IoT module' seller provided a document on how to start based on Mbed OS 5.11. (Created by CodeZoo) This guide has been supported to the latest os version which included 5.12 ~ 5.15.

  • if you need specific version of Mbed OS, please revision of TPB23_Driver and check it out.
  • Pelion ready example code is here!

Requirement

462 320 320

320

Tested with

1. Import the application into your desktop

mbed import http://os.mbed.com/users/Daniel_Lee/code/mbed-os-example-cellular-TPB23/

cd mbed-os-example-cellular-TPB23

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: Aug  7 2019, 06:10:47


[MAIN], plmn: NULL
Establishing connection
[00000001ms][INFO][CELL]: New CellularContext  (20000a08)
[00000002ms][INFO][CELL]: CellularContext plmn NULL
[00000003ms][INFO][CELL]: CellularContext connect
[00000036ms][INFO][CELL]: RSSI -69 dBm
[00000036ms][INFO][CELL]: Start connecting (timeout 1 s)
[00000087ms][INFO][CELL]: RSSI -69 dBm
[00000116ms][INFO][CELL]: Modem ready
[00000146ms][INFO][CELL]: RSSI -69 dBm
[00000146ms][INFO][CELL]: Setup SIM (timeout 1 s)
[00001233ms][INFO][CELL]: Looked up APN internet
[00001362ms][ERR ][CELL]: AT error code 50
[00001362ms][WARN][CELL]: Packet domain event reporting set failed!
[00001393ms][INFO][CELL]: RSSI -65 dBm
[00001393ms][INFO][CELL]: Network registration (timeout 180 s)
[00001443ms][INFO][CELL]: Registering network => Attaching network
[00001473ms][INFO][CELL]: RSSI -65 dBm
[00001473ms][INFO][CELL]: Attaching network (timeout 60 s)
[00001601ms][INFO][CELL]: Found PDP context 1
[00001649ms][INFO][CELL]: Activate PDP context 1


Connection Established.
[00001671ms][INFO][CELL]: Socket 0 open
[00001707ms][INFO][CELL]: Socket 1 open
[00001748ms][INFO][CELL]: Socket create id: 1
[00001883ms][INFO][CELL]: Socket 1 sent 43 bytes to 8.8.8.8 port 53
[00004311ms][INFO][CELL]: Socket 1 recv 59 bytes from 8.8.8.8 port 53
[00004331ms][INFO][CELL]: Close socket: 1 error: 0
[00004331ms][INFO][CELL]: Socket 1 closed
[00004373ms][INFO][CELL]: Socket create id: 1
TCP: connected with echo.mbedcloudtesting.com server
[00004448ms][INFO][CELL]: Socket 0 sent 4 bytes to 52.215.34.155 port 7
TCP: Sent 4 Bytes to echo.mbedcloudtesting.com
[00007560ms][INFO][CELL]: Socket 0 recv 4 bytes
[00007580ms][INFO][CELL]: Close socket: 1 error: 0
[00007580ms][INFO][CELL]: Socket 0 closed
Received from echo server 4 Bytes
[00007581ms][INFO][CELL]: CellularContext disconnect()
[00007630ms][INFO][CELL]: cb: CellularContext disconnected


Success. Exiting
Revision:
47:006469f922f6
Parent:
46:387c2d922a4a
--- a/SERCOMM/TPB23/SERCOMM_TPB23_CellularStack.cpp	Thu Aug 08 08:36:54 2019 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,255 +0,0 @@
-/*
- * Copyright (c) 2017, Arm Limited and affiliates.
- * 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 "SERCOMM_TPB23_CellularStack.h"
-#include "CellularUtil.h"
-#include "CellularLog.h"
-
-#define PACKET_SIZE_MAX 1500  //TPB23 Range is 12-1500
-
-using namespace mbed;
-using namespace mbed_cellular_util;
-
-SERCOMM_TPB23_CellularStack::SERCOMM_TPB23_CellularStack(ATHandler &atHandler, int cid, nsapi_ip_stack_t stack_type) : AT_CellularStack(atHandler, cid, stack_type)
-{
-    _at.set_urc_handler("+NSONMI:", mbed::Callback<void()>(this, &SERCOMM_TPB23_CellularStack::urc_nsonmi));
-}
-
-SERCOMM_TPB23_CellularStack::~SERCOMM_TPB23_CellularStack()
-{
-}
-
-nsapi_error_t SERCOMM_TPB23_CellularStack::socket_listen(nsapi_socket_t handle, int backlog)
-{
-    return NSAPI_ERROR_UNSUPPORTED;
-}
-
-nsapi_error_t SERCOMM_TPB23_CellularStack::socket_accept(void *server, void **socket, SocketAddress *addr)
-{
-    return NSAPI_ERROR_UNSUPPORTED;
-}
-
-nsapi_error_t SERCOMM_TPB23_CellularStack::socket_connect(nsapi_socket_t handle, const SocketAddress &address)
-{
-    CellularSocket *socket = (CellularSocket *)handle;
-
-    _at.lock();
-    if (!socket->created) {
-        const nsapi_error_t error_create = create_socket_impl(socket);
-        if (error_create != NSAPI_ERROR_OK) {
-            return error_create;
-        }
-    }
-
-    _at.cmd_start("AT+NSOCO=");
-    _at.write_int(socket->id);
-    _at.write_string(address.get_ip_address(), false);
-    _at.write_int(address.get_port());
-    _at.cmd_stop();
-    _at.resp_start();
-    _at.resp_stop();
-    _at.unlock();
-
-    if (_at.get_last_error() == NSAPI_ERROR_OK) {
-        socket->remoteAddress = address;
-        socket->connected = true;
-        return NSAPI_ERROR_OK;
-    }
-
-    return NSAPI_ERROR_NO_CONNECTION;
-}
-
-void SERCOMM_TPB23_CellularStack::urc_nsonmi()
-{
-    int sock_id = _at.read_int();
-
-    for (int i = 0; i < get_max_socket_count(); i++) {
-        CellularSocket *sock = _socket[i];
-        if (sock && sock->id == sock_id) {
-            if (sock->_cb) {
-                sock->_cb(sock->_data);
-            }
-            break;
-        }
-    }
-}
-
-int SERCOMM_TPB23_CellularStack::get_max_socket_count()
-{
-    return TPB23_SOCKET_MAX;
-}
-
-bool SERCOMM_TPB23_CellularStack::is_protocol_supported(nsapi_protocol_t protocol)
-{
-    return (protocol == NSAPI_UDP || protocol == NSAPI_TCP);
-}
-
-nsapi_error_t SERCOMM_TPB23_CellularStack::socket_close_impl(int sock_id)
-{
-    _at.cmd_start("AT+NSOCL=");
-    _at.write_int(sock_id);
-    _at.cmd_stop_read_resp();
-
-    tr_info("Close socket: %d error: %d", sock_id, _at.get_last_error());
-
-    return _at.get_last_error();
-}
-
-nsapi_error_t SERCOMM_TPB23_CellularStack::create_socket_impl(CellularSocket *socket)
-{
-    int sock_id = -1;
-    bool socketOpenWorking = false;
-
-    if (socket->proto == NSAPI_UDP) {
-        _at.cmd_start("AT+NSOCR=DGRAM,17,");
-    } else if (socket->proto == NSAPI_TCP) {
-        _at.cmd_start("AT+NSOCR=STREAM,6,");
-    } else {
-        return NSAPI_ERROR_PARAMETER;
-    }
-    _at.write_int(socket->localAddress.get_port());
-    _at.write_int(1);
-    _at.cmd_stop();
-    _at.resp_start();
-    sock_id = _at.read_int();
-    _at.resp_stop();
-
-    socketOpenWorking = (_at.get_last_error() == NSAPI_ERROR_OK);
-
-    if (!socketOpenWorking) {
-        _at.cmd_start("AT+NSOCL=0");
-        _at.cmd_stop_read_resp();
-
-        if (socket->proto == NSAPI_UDP) {
-            _at.cmd_start("AT+NSOCR=DGRAM,17,");
-        } else if (socket->proto == NSAPI_TCP) {
-            _at.cmd_start("AT+NSOCR=STREAM,6,");
-        }
-        _at.write_int(socket->localAddress.get_port());
-        _at.write_int(1);
-        _at.cmd_stop();
-        _at.resp_start();
-        sock_id = _at.read_int();
-        _at.resp_stop();
-
-        socketOpenWorking = (_at.get_last_error() == NSAPI_ERROR_OK);
-    }
-
-    if (!socketOpenWorking || (sock_id == -1)) {
-        tr_error("Socket create failed!");
-        return NSAPI_ERROR_NO_SOCKET;
-    }
-
-    // Check for duplicate socket id delivered by modem
-    for (int i = 0; i < TPB23_SOCKET_MAX; i++) {
-        CellularSocket *sock = _socket[i];
-        if (sock && sock->created && sock->id == sock_id) {
-            tr_error("Duplicate socket index: %d created:%d, sock_id: %d", i, sock->created, sock_id);
-            return NSAPI_ERROR_NO_SOCKET;
-        }
-    }
-
-    tr_info("Socket create id: %d", sock_id);
-
-    socket->id = sock_id;
-    socket->created = true;
-
-    return NSAPI_ERROR_OK;
-}
-
-nsapi_size_or_error_t SERCOMM_TPB23_CellularStack::socket_sendto_impl(CellularSocket *socket, const SocketAddress &address,
-                                                                     const void *data, nsapi_size_t size)
-{
-    int sent_len = 0;
-
-    if (size > PACKET_SIZE_MAX) {
-        return NSAPI_ERROR_PARAMETER;
-    }
-
-    char *hexstr = new char[size * 2 + 1];
-    int hexlen = char_str_to_hex_str((const char *)data, size, hexstr);
-    // NULL terminated for write_string
-    hexstr[hexlen] = 0;
-
-    if (socket->proto == NSAPI_UDP) {
-        _at.cmd_start("AT+NSOST=");
-        _at.write_int(socket->id);
-        _at.write_string(address.get_ip_address(), false);
-        _at.write_int(address.get_port());
-        _at.write_int(size);
-    } else if (socket->proto == NSAPI_TCP) {
-        _at.cmd_start("AT+NSOSD=");
-        _at.write_int(socket->id);
-        _at.write_int(size);
-    } else {
-        delete [] hexstr;
-        return NSAPI_ERROR_PARAMETER;
-    }
-
-    _at.write_string(hexstr, false);
-    _at.cmd_stop();
-    _at.resp_start();
-    // skip socket id
-    _at.skip_param();
-    sent_len = _at.read_int();
-    _at.resp_stop();
-
-    delete [] hexstr;
-
-    if (_at.get_last_error() == NSAPI_ERROR_OK) {
-        return sent_len;
-    }
-
-    return _at.get_last_error();
-}
-
-nsapi_size_or_error_t SERCOMM_TPB23_CellularStack::socket_recvfrom_impl(CellularSocket *socket, SocketAddress *address,
-                                                                       void *buffer, nsapi_size_t size)
-{
-    nsapi_size_or_error_t recv_len = 0;
-    int port;
-    char ip_address[NSAPI_IP_SIZE];
-
-    _at.cmd_start("AT+NSORF=");
-    _at.write_int(socket->id);
-    _at.write_int(size <= PACKET_SIZE_MAX ? size : PACKET_SIZE_MAX);
-    _at.cmd_stop();
-    _at.resp_start();
-    // receiving socket id
-    _at.skip_param();
-    _at.read_string(ip_address, sizeof(ip_address));
-    port = _at.read_int();
-    recv_len = _at.read_int();
-    int hexlen = _at.read_hex_string((char *)buffer, size);
-    // remaining length
-    _at.skip_param();
-    _at.resp_stop();
-
-    if (!recv_len || (recv_len == -1) || (_at.get_last_error() != NSAPI_ERROR_OK)) {
-        return NSAPI_ERROR_WOULD_BLOCK;
-    }
-
-    if (address) {
-        address->set_ip_address(ip_address);
-        address->set_port(port);
-    }
-
-    if (recv_len != hexlen) {
-        tr_error("Not received as much data as expected. Should receive: %d bytes, received: %d bytes", recv_len, hexlen);
-    }
-    return recv_len;
-}