●The serial port level is same as the power supply voltage.●Input voltage: 3.3V/5V,only requires a set of power supply.
●With built-in level conversion function.
If you use 5.0V MCU to communicate with AT-09, the 5.0V power port provides power, RX TX logic level is 5V.
If it's 3.3V MCU used to communicate with AT-09, the 3.3V power port supplies power, RX TX logic level is 3.3V.
●RX, AT-09 serial receiving port is connected with TXD of MCU.
TX, AT-09 serial transmitter port is connected with RXD of MCU.
GND, negative power supply.
3.3V, 3.3V power supply.
5V, 5V power supply