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:
0:4611f6cf2413
Child:
2:0f644d6045cf
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Mar 08 17:31:37 2018 +0000
@@ -0,0 +1,223 @@
+/*
+ * 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.u-blox.com";
+
+// Echo server port (same for TCP and UDP)
+const int port = 7;
+
+Mutex PrintMutex;
+Thread dot_thread;
+
+#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