Pinout

Note

• This page lists the pinout of the FLY-RPFMEX mainboard after flashing Klipper firmware. Pin numbers are based on the mainboard schematic.
• UART is the TMC2209 driver communication pin.
• EN is the enable pin. In Klipper configuration, it is usually 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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Interactive Pin Hotspots

The image below uses the product image of FLY-RPFMEX and the same hotspot data. Use the device-type filters to show only compatible connectors; click a hotspot to see which devices it accepts, common Klipper configuration options, and notes. Hover to see the connector name and pins; always verify the silkscreen and connector positions against the physical board and schematic.

Filter by deviceClick a device type to show only connectors that support it; click again to clear the filter.

FLY-RPFMEXMotor driversThermistorsFansEndstopsProbe

Hover to see the pin; click a hotspot to view compatible devices and configs. Pins can be copied from the detail panel, except for driver connectors.

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Driver Pins

The FLY-RPFMEX provides 4 driver ports:

Driver	STEP	DIR	EN	UART	DIAG
DRIVER0	gpio6	gpio5	gpio9	gpio7	gpio8
DRIVER1	gpio1	gpio0	gpio4	gpio2	gpio3
DRIVER2	gpio22	gpio21	gpio25	gpio23	gpio24
DRIVER3	gpio17	gpio16	gpio20	gpio18	gpio19

DIAG and Sensorless Homing

The DIAG signals of DRIVER0–3 are independently and directly connected to the main MCU GPIOs. When using sensorless homing, configure diag_pin directly according to the DIAG pin in the driver table:

Driver	DIAG / diag_pin
DRIVER0	gpio8
DRIVER1	gpio3
DRIVER2	gpio24
DRIVER3	gpio19

These DIAG pins are not the regular endstop ports in the "Endstops" table below. Enabling sensorless homing will not occupy the standard endstop inputs gpio27, gpio28, gpio29.

Endstops and Temperature Multiplexing

Function	Pin	Notes
Endstop / ADC Shared Port 1	gpio27	Shared with Thermistor Port 1
Endstop / ADC Shared Port 2	gpio28	Shared with Thermistor Port 2
Endstop / ADC Shared Port 3	gpio29	Shared with Thermistor Port 3

For wiring of micro switches, optical endstops, proximity sensors, and TAP, see: Endstop Wiring Guide

Temperature Sensors

Function	Pin	Notes
Thermistor Port 1	gpio27	Shared with Endstop / ADC Shared Port 1
Thermistor Port 2	gpio28	Shared with Endstop / ADC Shared Port 2
Thermistor Port 3	gpio29	Shared with Endstop / ADC Shared Port 3

Power Off Operation

Before starting, completely turn off the printer and disconnect the power supply. Do not plug or unplug wiring harnesses, organize interface wiring, or touch terminals while the system is powered on.

Interface Multiplexing

gpio27, gpio28, and gpio29 support both general-purpose input and ADC sampling functions, but can only be used for one purpose at a time. After configuring them as thermistor inputs, do not configure the same interface as a mechanical endstop or other input. On the left side of the interface diagram, from top to bottom, the pins are gpio29, gpio28, gpio27. Please verify according to the actual wiring order.

Supported Thermistor Types

The thermistor ports support NTC thermistors (100K) by default, with sensor_type recommended as Generic 3950; they also support 2-wire PT1000, configured by setting sensor_type to PT1000.

List of sensor_type options that can be directly connected internally by Klipper and their applicable scenarios: Thermistor Configuration Method

K-type thermocouples, 3-wire PT100, etc., require additional signal conditioning chips and cannot be connected directly to the thermistor ports.

Fans

Function	Pin	Notes
Fan 0	gpio11	Controllable output
Fan 1	gpio12	Controllable output
Fan 2	-	Always-on power port, not controlled by MCU

General Purpose Input

Function	Pin	Notes
HV-IN / General Purpose Input	gpio10	Input port, not used as RGB output

PWM

PWM	Pin	Notes
PWM0	gpio11	Fan 0
PWM1	gpio12	Fan 1

Screen / EXP Notes

Interface Notes

The FLY-RPFMEX does not provide standard EXP1 / EXP2 12864 pin headers. Please use the driver, endstop, temperature, fan, and general-purpose input interfaces listed on this page. Do not apply the EXP1 / EXP2 pinout tables from other mainboards.