Overview

HC-05 module is an easy to use Bluetooth SPP (Serial Port Protocol) module, designed for transparent wireless serial connection setup.

Specification

• Bluetooth module HC-05

• Operating Supply Voltage : +3.6V ~ +5V

• Version : Bluetooth V2.0 protocol standards

• Interface : UART(3.3V Level) - VCC, GND, TX, RX

• Modes : Master or Slave (use AT Command to select)

• Default setting : Slave mode, baud rate: 9600bps, password: 1234

Pin Definitions

• VCC : Connect to DC3.6V ~ 5V

• GND : Connect to ground

• TXD : Connect to MCU's RXD (3.3V level)

• RXD : Connect to MCU's TXD (3.3V level)

• KEY(input) : Use to set AT command mode('H') or
  automatic binding transparent data mode('L')

• LED(output) : Pairing status indication. 'H' for pairing sucess; 'L' not yet pairing.

On Board LED Indication

1. During power up, set KEY to 'H', LED show slow blinking(1Hz), module go into AT Command mode, default baudrate is 38400bps.

2. During power up, set KEY to 'L' or floating, LED show blinking(2Hz), module is waiting for pairing. If set KEY to 'H', module will go into AT Command mode.

3. After pairing sucess, LED show double blinking(0.5Hz).