Expansion Port

Pin 1 is in the bottom-left corner. Pin 2 is in the upper-left corner.

Pin	Name	RegisterName	Function	VoltageLevel	Comment
1	5V			5V	5V Rail on FC, PDB includes supply
2	GND
3	3V3			3.3V	3V Rail on FC + PDB, FC includes supply
4	D12	PB_4	SPI3_MISO	3.3V
5	A4	PA_5	DAC
6	D11	PB_5	SPI3_MOSI	3.3V
7	A3	PA_4	DAC	3.3V	Differential Pressure Sensor (MPXV5004G) Input
8	D10	PA_11	SPI3_CS	3.3V	PDB ATmega Chip Select
9	A0	PA_0
10	D9	PA_8	PWM1/1
11	D13	PB_3	SPI3_SCK	3.3V
12	D2	PA_12
13	D5	PB_6	I2C1_SCL	5V	FC main I2C Bus Clock, Sensors, Mission Critical
14	D1	PA_9	PWM1/2
15	D4	PB_7	I2C1_SDA	5V	FC main I2C Bus Data, Sensors, Mission Critical
16	!RST		RESET	3.3V	FC Reset, Mission Critical

NOTE: In PDB2/FC4 I2C is on 3.3V logic level