Bluetooth-pin interface: (PIN to PIN space: standard 2.54mm) 1. STATUS: Bluetooth status output sustained high level indicates that the data link has been established. Microcontroller IO port can be connected to query the status of Bluetooth ; It is not essential to connected STATUS 2. VCC: power connector 5V. (Must be connected) 3. GND: negative power (Must be connected) 4.TXD: data output interface you need to connect the microcontroller data input interface; Generally the name of MCU IO is RX or RXD. 5. RXD: data reception interface you need to connect the microcontroller data transmission interface; Generally the name single-chip IO is TX or TXD. 6. MCLR: Clear the pairing function of main module; Generally connect to one of microcontroller IO; Microcontroller outputs a 500ms low level then output high level to clear the Bluetooth host pairing information