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Pinout

Note
  • This page lists the pinout of the FLY-E3 V2 mainboard after flashing Klipper firmware. Pin numbers are based on the mainboard schematic.
  • UART/CS is the driver communication pin: used as UART with TMC2209, or as chip select CS with 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:

DriverSTEPDIRENUART/CSDIAG
DRIVER0PE5PC0PC1PC15PE7
DRIVER1PE4PC13PC14PB6PE8
DRIVER2PE1PB7PE3PD7PE9
DRIVER3PE2PD5PD6PD4NC
DRIVER4PE0PD1PD3PD0NC
Power Off Before Operation

Before starting, completely shut down the printer and disconnect the power supply. Do not plug or unplug wiring harnesses, rearrange interface cable routing, or touch terminals while the power is on.

DIAG and Sensorless Homing

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

  • DRIVER0–2: The DIAG signal is directly connected to the corresponding endstop input port on the main controller (DRIVERn → endstop port n). There are no DIAG jumper pins on the board, and the DIAG signal is always sent to the main controller. 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: The DIAG signal is not routed to the endstop ports, so sensorless homing cannot be configured according to the table.

Once sensorless homing is enabled, the corresponding endstop port is occupied by the DIAG signal. Do not connect mechanical or optical endstop switches to it simultaneously.

SPI Bus​

SPI drivers such as the TMC5160 use the mainboard's hardware SPI bus. Simply configure spi_bus: spi3 in the configuration; no need to configure MOSI/MISO/SCLK pins separately:

[tmc5160 stepper_x]
spi_bus: spi3
cs_pin: corresponding driver's UART/CS pin

Detailed explanation of software SPI and SPI speed, etc.：SPI Configuration Guide

Endstops and Probe​

FunctionPinCorresponding Driver DIAG
Endstop Port 0 / IO0PE7DRIVER0
Endstop Port 1 / IO1PE8DRIVER1
Endstop Port 2 / IO2PE9DRIVER2
ProbePC2-

Heating​

FunctionPin
Heater Port 0PC6
Heater Port 1PC7
Heater Port 2PB0

Temperature Sensors​

FunctionPin
Thermistor Port 0PC4
Thermistor Port 1PB1
Supported Thermistor Types

The thermistor ports support NTC thermistors (100K) by default. It is recommended to configure sensor_type as 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 conversion chips and cannot be directly connected to the thermistor ports.

Fans​

FunctionPin
Fan Port 0PA0
Fan Port 1PA1
Fan Port 2PA2
Fan Port 3PA3

PWM​

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

PinRemarks
PE6Servo / BLTouch control

BL-Touch​

FunctionPin
Servo SignalPE6
Probe SignalPC2
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