LIN: Audio input, connected to the left channel of the headphones.
RIN: Audio input, connected to the right channel of the headphones.
Vin: The power supply voltage is 3-5VDC.
3V0: This is the regulator interface, connected to 3.3V, if you need 100mA of 3 volts, you can use this adjustment to adjust the voltage.
CS: Select pin for spi mode. The i2c address is determined. When connected high (default), the i2c address is 0x63. If grounded or shorted, the i2c address is 0x11.
SCL: Clock pin, connected to the microcontroller.
SDA: Data pin, connected to the microcontroller.
GPIO: Can be used to flash the LED, the initial state has been set, 3V output.
1 X CJMCU-4713 SI4713 Stereo FM Transmitter Module