Features bluetooth 4 0 module Serial port extraction bluetooth BLE CC2540 CC2541 The bluetooth module has a backplane and the HM 10 module is used on this module 5V power supply or 3 3V power supply The serial port level is the same as the power supply voltage Built in level shifting function Specifications Input voltage 3 3V 5V If a 5 0V MCU is used to communicate with the bluetooth module the 5 0V power port is powered and the RX TX logic level is 5V If a 3 3V MCU is used to communicate with the bluetooth module the 3 3V power port is powered and the RX TX logic level is 3 3V Pin RX the serial port receiving end of the bluetooth module is connected to the TXD of the MCU TX the serial port sender of the bluetooth module is connected to the RXD of the MCU GND ground terminal negative3 3V 3 3V power supply at the power supply5V power supply 5V power supply Package Incleded 3 x AT 09 4 0 BLE Wireless bluetooth Module