I2CSupported. SDA & SCL pads on front side. Used for magnetometer, sonar, etc.
LED PadUsed for WS2812 LED controlled by Betaflight firmware.
BuzzerBZ+ and BZ- pad used for 5V Buzzer
[A]. Press and hold BOOT button and power the FC on at the same time will force the FC to enter DFU mode, this is for firmware flashing when the FC gets bricked.
[B]. When the FC is powered on and in standby mode, the BOOT button can be used to controller the LED strips connected to LED1-LED4 connectors on the bottom side. By default, short-press the BOOT button to cycle the LED displaying mode. Long-press the BOOT button to switch between SpeedyBee-LED mode and BF-LED mode. Under BF-LED mode, all the LED1-LED4 strips will be controlled by Betaflight firmware.
RSSI InputSupported. Named as RS on the front side.