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AT command is used to communicate with a communication device, such as a modem or a Wi-Fi module. Mbed OS has ATCmdParser class to implement functionality to send and receive AT commands to the devices capable of using AT commands.
Some NuMaker-IoT boards have Wi-Fi modules, which are controlled by AT commands based on the ESP8266 chip.
- NuMaker-IoT-M467
- NuMaker-IoT-M487
- NuMaker-IoT-M263A
- NuMaker-M2354
- NuMaker-PFM-M2351
You need an Mbed OS account to use Mbed tools, please register one if you don't have it.
https://os.mbed.com
Then download and install Mbed Studio which is a offline IDE tool provided by Arm for developing Mbed OS applications.
https://os.mbed.com/studio
Run Mbed Studio, and import example code to create a new project.
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Fill the example link to "URL" https://github.com/ARMmbed/mbed-os-snippet-AT_CmdParser
Then click "Add Program"
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"Active program" should be "mbed-os-snippet-at_cmdparser". If not, please select it.
Then select NuMaker-IoT-M467 to "Target" on the pull down menu.
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Click "main.cpp" to show the source code. BufferSerial object is the UART port connected to Wi-Fi module. Declare a ATCmdParser object with the BufferSerial object. Send a get version command “AT+GMR” to the ESP8266 Wi-Fi module to get version number. Receive and parse the response string to get the version field.
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Modify UART pins connect to Wi-Fi module. Here lists Wi-Fi module pins (Tx, Rx) for NuMaker boards:
- NuMaker-IoT-M467 : PC_1, PC_0
- NuMaker-IoT-M487 : PH_8, PH_9
- NuMaker-IoT-M263A : PC_7, PC_6
- NuMaker-M2354 : PC_7, PC_6
And the code at line 36 has a little bug so we have to fix it. The correct code should be
Code: Select all
if (_parser->recv(“SDK version:%d”, &version) && _parser->recv(“OK”))
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Click hammer to build code.
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While building the code, let's check NuMaker board, please make sure that no.1 & 2 are ON and no.3 & 4 are OFF of ICESW2 on Nu-Link2-ME. Then plug its USB to PC. You will find a NuMicro MCU drive on PC.
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When build is completed, you get the binary firmware file "mbed-os-snippet-at_cmdparser.bin" in "C:\Users\YOUR-ACCOUNT\Mbed Programs\mbed-os-snippet-at_cmdparser\BUILD\NUMAKER_IOT_M467\ARMC6" folder. Just copy the binary firmware to NuMicro MCU drive.
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Mbed Studio automatically open a terminal when a Mbed Enabled board detected. Or you can use other terminal tool to open Nu-Link2-Me virtual COM port and select the baud rate to 9600.
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You can press RESET button on NuMaker-IoT-M467 board to restart firmware. Then the running information shows on terminal.
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This is a simple way to use Mbed OS's ATCmdParser class library to control a AT Command module on NuMaker boards. If you have any problems, please contact us SalesSupport@nuvoton.com