Configure the BLE through AT command

Last revision 2026/01/14

This article is a detailed guide on configuring BLE modules through AT commands, with step-by-step instructions for firmware versions 1.8 and earlier, utilizing the Arduino IDE and serial monitor for effective Bluetooth communication.

Configure the BLE through AT command

Version 1.8 or later

The AT Mode Switch becomes useless at Firmware version V1.8 or later.

1. Open the Arduino IDE.

2. Select the correct serial port in Menu->Tool->Serial port

3. Open the Serial monitor (on the upper right of the IDE windows)

4. Select the "No line ending"(①) and 115200 baud(②) in the two pull-down menu

5. Type "+++"(③) like this and press send button(④)

6. If the AT Command Mode is successfully Entered , you will receive "Enter AT Mode"(⑤) from it.

Fig1: +++ enter the AT CMD Mode

7. Select the "Both NL & CR"(①) and 115200 baud(②) in the two pull-down menu

8. Type or copy the AT command in the dialog(③) like this and press send button(④)

9. If the BLE is successfully configured , you will receive "OK"(⑤) from it.

Fig1: enter the AT command,remember selectting the Both NL & CR

10. If received "ERROR CMD" instead, try sending it again or you should check whether the command is correct or not.

11. ''' USE “AT+EXIT” to exit AT Mode '''

Version 1.7 or before

1. Turn the on-board switch to "AT" and AT command mode will be entered.

2. We need a serial monitor for configuring the BLE in this part. There're lots of good tools like putty,CoolTerm and Arduino serial monitor. In this case, we choose the Arduino Serial monitor, which is easy to use.

3. Select the correct serial port in Menu->Tool->Serial port

4. Open the Serial monitor (on the upper right of the IDE windows)

Fig1: Coolterm setting

5. Select the "Both NL & CR"(①) and 115200 baud(②) in the two pull-down menu

6. Type or copy the AT command in the dialog(③) like this and press send button(④)

7. If the BLE is successfully configured , you will receive "OK"(⑤) from it.

8. If received "ERROR CMD" instead, try sending it again or you should check whether the command is correct or not.

9. Turn the switch to "NORM", entering the normal mode

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