AT Mode Configuration Guide

How to enter into AT mode

The DF-Bluetooth V3 module has two switches on the module.

• The NO.1 switch is used to set the LINK-LED on/off for power saving.(1 for off, ON for on)
• The NO.2 switch is used to turn on/off AT mode of the Bluetooth module (On->Enter; 2->Exit)
  • In AT mode
  • In Functional mode

So if you turn the NO.2 switch on, you can use the AT mode to set the Bluetooth module, e.g. name, baud rate, master/slave mode etc.

Hardware Preparation

• TEL0010 USB to TTL Converter x1
• TEL0026 Bluetooth module x1

Software Preparation

• Download and install the CoolTerm: Click to download CoolTerm

Note: you can also use Arduino IDE serial monitor.

Steps

Part 1: Ready to go

1. Plug the Bluetooth module into the USB to TTL module;
2. Turn on the AT mode switch of the Bluetooth module;
3. Connect the USB to TTL module to your computer;
4. Install the driver for the USB to Serial module if it can't be recognized.

Part 2: Setting

After connecting the module to computer, we can use CoolTerm software to talk with Bluetooth module.

1. Click Connection --> Choose Options to set several parameters in CoolTerm.
2. Set Serial Port
   1. Port: the port number can be got from the Device Manager of the computer
   2. Baudrate: 38400
   3. Data Bits: 8
   4. Parity : none
   5. Stop Bits: 1
3. Set Terminal
   1. Terminal Mode: Line Mode
   2. Key Emulation: CR+LF

Part 3: Setting

Now use the CoolTerm to send AT commands to the Bluetooth Module and see what information the Bluetooth will answer to the computer.

For example:

• Input: at

• Return: OK

• Input: at+name=DFRobot

• Return: OK

• Input: at+name?

• Return: +name: DFRobot OK

• Input: at+role=0

• Return: OK

• Input: at+role?

• Return: +role:0 OK

• AT+PSWD?

• +PSWD:1234 OK

• AT+ORGL (Restore the default setting:)

• Return: OK

• AT+UART=115200,0,0 Return: OK

• Param1: baud rate (bits/s) 4800/ 9600/ 19200/ 38400/ 57600/ 115200/ 230400/ 460800/ 912600/ 1382400

• Param2: stop bit , 0- 1 bit/ 1- 2 bits

• Param3: parity bit, 0- None/ 1- Odd/ 2- Even

• AT+RESET

• Return: OK

• Default setting
  1. Device class: 0
  2. Inquiry code: 0x009e8b33
  3. Device mode: Slave mode
  4. Binding mode: SPP
  5. Serial port: 38400 bits/s; 1 stop bit, no parity (In datasheet, it said the default baud rate is 9600 which is wrong.)
  6. Pairing code: “1234”
  7. Device name: “HHW-SPP-1800-2

Note: More AT command can be obtained from the Datasheet.

Part 4: Exit AT mode

Please turn the AT mode switch off and then repower the Bluetooth module.