Pinout

Note

• This page lists the pinout of the FLY-E3 V2 motherboard after flashing Klipper firmware. Pin numbers are subject to the motherboard schematic.
• UART/CS is the driver communication pin: used as UART with TMC2209, or as chip select CS when using SPI drivers such as TMC5160. The same pin is multiplexed.
• EN is the enable pin. In Klipper configuration, it is typically active-low (with ! prefix in enable_pin).
• DIAG is the driver diagnostic signal pin. When using sensorless homing, configure the corresponding diag_pin according to the table below.

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Driver Pins

The FLY-E3 V2 provides 5 driver ports:

Driver	STEP	DIR	EN	UART/CS	DIAG
DRIVER0	PE5	PC0	PC1	PC15	PE7
DRIVER1	PE4	PC13	PC14	PB6	PE8
DRIVER2	PE1	PB7	PE3	PD7	PE9
DRIVER3	PE2	PD5	PD6	PD4	NC
DRIVER4	PE0	PD1	PD3	PD0	NC

Power Off Before Operation

Before starting, completely shut down the printer and disconnect the power supply. Do not plug or unplug cables, organize wiring, or touch terminals while the power is on.

DIAG and Sensorless Homing

When using sensorless homing, the driver chip outputs a stall detection signal through the DIAG pin. Klipper needs to read this signal via the corresponding input port. The mapping between DIAG and endstop ports on this motherboard is as follows:

• DRIVER0–2: The DIAG signal is directly connected to the corresponding endstop input port on the MCU (DRIVERn → Endstop port n). There are no DIAG jumper pins on the board, and the DIAG signal is always sent to the MCU. When enabling sensorless homing, simply configure the corresponding endstop port pin as diag_pin. Do not connect a physical endstop switch to that endstop port.
• DRIVER3 / DRIVER4: DIAG is not routed to an endstop port, so sensorless homing cannot be configured directly according to the table.

Once sensorless homing is enabled, the corresponding endstop port is occupied by the DIAG signal. Do not connect a mechanical or optical endstop switch to it at the same time.

SPI Bus

SPI drivers such as the TMC5160 use the motherboard's hardware SPI bus. In the configuration, simply set spi_bus: spi3 — there is no need to configure MOSI/MISO/SCLK pins separately:

[tmc5160 stepper_x]
spi_bus: spi3
cs_pin: UART/CS pin of the corresponding driver

Detailed information on software SPI and SPI speed: SPI Configuration Method

Endstops and Probe

Function	Pin	Corresponding Driver DIAG
Endstop port 0 / IO0	PE7	DRIVER0
Endstop port 1 / IO1	PE8	DRIVER1
Endstop port 2 / IO2	PE9	DRIVER2
Probe	PC2	-

Heating

Function	Pin
Heater port 0	PC6
Heater port 1	PC7
Heater port 2	PB0

Temperature Sensors

Function	Pin
Thermistor port 0	PC4
Thermistor port 1	PB1

Supported Thermistor Types

The thermistor ports support NTC thermistors (100K) by default. It is recommended to set sensor_type to Generic 3950.

List of built-in sensor_type options directly compatible with Klipper and their applicable scenarios: Thermistor Configuration Method

K-type thermocouples, PT100, etc., require additional signal conversion chips and cannot be connected directly to the thermistor ports.

Fans

Function	Pin
Fan port 0	PA0
Fan port 1	PA1
Fan port 2	PA2
Fan port 3	PA3

PWM

The FLY-E3 V2 provides 1 PWM output, which can be used for servos, fan speed control, etc.:

Pin	Note
PE6	Servo / BLTouch control

BL-Touch

Function	Pin
Servo signal	PE6
Probe signal	PC2

EXP Interface

EXP Configuration Reminder

• The EXP headers are commonly used for Mini12864 displays or other expansion peripherals.
• If a pin is already used by SPI, UART, endstop, fan, or other functions, do not configure it again in the EXP peripheral.

EXP1

Function	Pin
EXP1_1	PD10
EXP1_2	PA9
EXP1_3	PA8
EXP1_4	PA10
EXP1_5	PE15
EXP1_6	PE14
EXP1_7	PA14
EXP1_8	PA13
EXP1_9	GND
EXP1_10	5V

EXP2

Function	Pin
EXP2_1	PA6
EXP2_2	PA5
EXP2_3	PB11
EXP2_4	PA4
EXP2_5	PB10
EXP2_6	PA7
EXP2_7	PE13
EXP2_8	RST
EXP2_9	GND
EXP2_10	NC