Pinout

Description

• This page lists the pinout of the SB2040-PRO tool board after flashing Klipper firmware. Pin numbers are based on the product schematic.
• UART/CS is the driver communication pin: when using TMC2240, it serves as UART; when using an SPI driver, it serves as chip select CS. The same pin is multiplexed.
• EN is the enable pin. In Klipper configuration, it is typically active low (enable_pin with a ! prefix).

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Interactive Pin Hotspots

The image below uses the product image of FLY-SB2040 Pro 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-SB2040 ProMotor driversHeatersThermistorsFansEndstopsRGB

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

Driver	STEP	DIR	EN	UART/CS	Endstop
DRIVER0	gpio9	gpio10	gpio7	gpio11	-

Power Off Before Operation

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

Heating

Function	Pin
Hotend heater	gpio6

Temperature Sensors

Function	Pin
Hotend thermistor	gpio27
Enclosure thermistor	gpio26

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
Part cooling fan	gpio13
Heatbreak cooling fan	gpio14

Probe and Endstops

Function	Pin
HV-IN / General input	gpio28
X endstop	gpio29
Probe / General input	gpio25

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

RGB

Function	Pin
RGB / Neopixel	gpio12

Accelerometer (SPI)

The accelerometer uses software SPI and requires three separate signal pins to be specified:

Signal	Pin
CS	gpio1
MOSI	gpio3
MISO	gpio2
SCLK	gpio0

PWM

PWM Function	Pin
RGB / Neopixel	gpio12