| Pin | Name | Function |
|---|---|---|
| 1 | EN/KEY | Pull HIGH to enter AT command mode; floating/LOW = data mode |
| 2 | VCC | Power supply, 3.3-5V |
| 3 | GND | Ground |
| 4 | TXD | Transmit - connect to microcontroller RX |
| 5 | RXD | Receive - connect to microcontroller TX (use a voltage divider from 5V) |
| 6 | STATE | Goes HIGH when paired/connected |
Summary
Serial (SPP) Bluetooth module for wireless UART communication. Can act as master or slave, making it a simple way to add wireless control or telemetry to Arduino-class boards.
- Operating voltage: 3.3V - 5V (logic is 3.3V, needs level shifting on RX for 5V MCUs)
- Default baud rate: 9600bps (data mode), 38400bps (AT command mode)
- Range: ~10m (class 2)
- Mode: Master or Slave (set via AT commands)