Ublox Modem Interface

This content relates to a deprecated version of Mbed

Mbed 2 is now deprecated. For the latest version please see the Mbed OS documentation.

Networking

  1. Introduction
  2. Socket API
  3. Protocols and APIs
  4. Ethernet Interface
  5. u-blox modem interface

u-blox is a leading provider of GSM and CDMA modems. LISA-U2 (GSM) and LISA-C200 (CDMA) can be easily connected to a mbed board using the UbloxUSBModem library (below), making it possible to connect your mbed device to the Internet from almost anywhere in the world.

Hardware Setup

Currently, the LISA-U2 and LISA-C200 can be connected to a LPC1768 mbed using the USB controller inside the LPC1768 in host mode (more details here).

Hello World

This example application uses the UbloxUSBModem and the HTTPClient interface, enabling the mbed to fetch a URL over HTTP, and print the contents.

There are various other "hello world" programs that demonstrate SMS, Socket and Websocket interfaces. See "Resources" section below.

You'll notice that this "Hello World" program is a little more complex that others, as we're using the mbed RTOS to manage the memory and processing resources/requirement of the USB Modem driver and the TCP/IP stack.

Import program
UbloxModemHTTPClientTest - main.cpp

00001 #include "UbloxUSBGSMModem.h"
00002 #include "UbloxUSBCDMAModem.h"
00003 #include "httptest.h"
00004 
00005 #if !defined(MODEM_UBLOX_GSM) && !defined(MODEM_UBLOX_CDMA)
00006 #warning No modem defined, using GSM by default
00007 #define MODEM_UBLOX_GSM
00008 #endif
00009 
00010 #ifndef MODEM_APN
00011 #warning APN not specified, using "internet"
00012 #define MODEM_APN "internet"
00013 #endif
00014 
00015 #ifndef MODEM_USERNAME
00016 #warning username not specified
00017 #define MODEM_USERNAME NULL
00018 #endif
00019 
00020 #ifndef MODEM_PASSWORD
00021 #warning password not specified
00022 #define MODEM_PASSWORD NULL
00023 #endif
00024 
00025 int main()
00026 {
00027 #ifdef MODEM_UBLOX_GSM
00028     UbloxUSBGSMModem modem;
00029 #else
00030     UbloxUSBCDMAModem modem(p18, true, 1);
00031 #endif
00032     httptest(modem, MODEM_APN, MODEM_USERNAME, MODEM_PASSWORD);
00033     while (true);
00034 }
00035

Import program
UbloxModemHTTPClientTest - httptest.cpp

00001 #include "mbed.h"
00002 #include "CellularModem.h"
00003 #include "HTTPClient.h"
00004 #include "httptest.h"
00005 
00006 int httptest(CellularModem& modem, const char* apn, const char* username, const char* password)
00007 {    
00008     printf("Connecting...\n");
00009     
00010     HTTPClient http;
00011     char str[512];
00012 
00013     modem.power(true);
00014     Thread::wait(1000);
00015     int ret = modem.connect(apn, username, password);
00016     if(ret)
00017     {
00018       printf("Could not connect\n");
00019       return false;
00020     }
00021     
00022     //GET data
00023     printf("Trying to fetch page...\n");
00024     ret = http.get("http://mbed.org/media/uploads/donatien/hello.txt", str, 128);
00025     if (!ret)
00026     {
00027       printf("Page fetched successfully - read %d characters\n", strlen(str));
00028       printf("Result: %s\n", str);
00029     }
00030     else
00031     {
00032       printf("Error - ret = %d - HTTP return code = %d\n", ret, http.getHTTPResponseCode());
00033       modem.disconnect();
00034       return false;
00035     }
00036     
00037     //POST data
00038     HTTPMap map;
00039     HTTPText text(str, 512);
00040     map.put("Hello", "World");
00041     map.put("test", "1234");
00042     printf("Trying to post data...\n");
00043     ret = http.post("http://httpbin.org/post", map, &text);
00044     if (!ret)
00045     {
00046       printf("Executed POST successfully - read %d characters\n", strlen(str));
00047       printf("Result: %s\n", str);
00048     }
00049     else
00050     {
00051       printf("Error - ret = %d - HTTP return code = %d\n", ret, http.getHTTPResponseCode());
00052       modem.disconnect();
00053       return false;
00054     }
00055     
00056     modem.disconnect();
00057     return true;
00058 }

Library

Import libraryUbloxUSBModem

u-blox USB modems (GSM and CDMA)

Last commit 04 Mar 2014 by mbed official

Resources and references

Network APN

To connect to the internet you must establish a PPP connection. You can then use BSD Sockets or any high-level component (HTTP Client, NTP Client).

To establish this connection, one single function is used:

int ret = modem.connect("internet");

internet is the APN that you need to provide to establish a data connection. Change it to the relevant value if your SIM is different.

The variable, "ret", allows you to check whether the connection was successful or not (0 on success, a negative value on error).

Please note that the "connect" command can take a few minutes to complete in worst case scenarios, as it initializes the modem and then waits for network registration.

Other Examples

Import programUbloxModemSMSTest

u-blox modem SMS test

Last commit 03 Jun 2014 by mbed official

Import programUbloxModemWebsocketTest

u-blox modem Websockets client test

Last commit 31 Oct 2013 by mbed official

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