Pin Mapping

Note

• This page lists the pin mapping of the FLY-E3 Ultra motherboard after flashing Klipper firmware. The pin numbers are based on the motherboard schematic.
• UART/CS is the driver communication pin: when using TMC2209, it functions as UART; when using SPI drivers such as TMC5160, it functions as chip select CS. The same pin is multiplexed.
• EN is the enable pin. In Klipper configuration, it is typically active-low (prefixed with ! 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 Ultra provides 5 driver ports:

Driver	STEP	DIR	EN	UART/CS	DIAG
DRIVER0	PC13	PC0	PC15	PC14	-
DRIVER1	PE3	PE2	PE5	PE4	PD12
DRIVER2	PD1	PD0	PE1	PE0	PB10
DRIVER3	PA15	PD7	PC2	PA8	PC4
DRIVER4	PD4	PD3	PD6	PD5	-

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 system is powered on.

DIAG and Sensorless Homing

In the table, rows where the corresponding driver DIAG is not - indicate that the driver's DIAG signal is connected to the corresponding input port on the main controller. When enabling sensorless homing, configure diag_pin directly according to the table. The corresponding input port will be occupied by the DIAG signal; do not connect mechanical or optical endstops to it simultaneously. Drivers without a listed DIAG correspondence cannot be used for sensorless homing directly as per the table.

Endstops and Probe

Function	Pin	Corresponding Driver DIAG
Endstop Port 0 / IO0	PD12	DRIVER1
Endstop Port 1 / IO1	PB10	DRIVER2
Endstop Port 2 / IO2	PC4	DRIVER3
Probe	PC5	-

Heating

Function	Pin
Heated Bed Heating	PA0
Heater Port 0	PA2
Heater Port 1	PC6

Temperature Sensors

Function	Pin
Heated Bed Thermistor	PA3
Thermistor Port 0	PA4
Thermistor Port 1	PA1

Supported Thermistor Types

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

List of built-in sensor_type options directly supported by Klipper and their applicable scenarios: Thermistor Configuration Guide

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	PD15
Fan Port 1	PD14
Fan Port 2	PB6
Fan Port 3	PB7

PWM

The FLY-E3 Ultra provides 5 PWM outputs, which can be used for servos, fan speed control, etc.:

Pin	Notes
PB0	Servo / BLTouch Control
PD10	PWE-DE
PB1	LASER
PD11	PS-ON
PB11	RGB / Neopixel

BL-Touch

Function	Pin
Servo Signal	PB0
Probe Signal	PC5

RGB

Function	Pin
RGB / Neopixel	PB11

EXP Interface

EXP Configuration Reminder

• The EXP headers are commonly used for screens such as the Mini12864 or for expanding peripherals.
• If a pin is already occupied by SPI, UART, endstop, fan, or other functions, do not reconfigure it for EXP peripherals.

EXP1

Function	Pin
EXP1_1	PE11
EXP1_2	PE12
EXP1_3	PA14
EXP1_4	PE6
EXP1_5	PE9
EXP1_6	PE10
EXP1_7	PE7
EXP1_8	PE8
EXP1_9	GND
EXP1_10	5V

EXP2

Function	Pin
EXP2_1	PB4
EXP2_2	PB3
EXP2_3	PA10
EXP2_4	PB2
EXP2_5	PA9
EXP2_6	PB5
EXP2_7	PA13
EXP2_8	RST
EXP2_9	GND
EXP2_10	NC