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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Driver Pins

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

Heating

Function	Pin
Hotend heater	gpio6

Temperature Sensors

Function	Pin
Hotend thermistor	gpio27
Enclosure thermistor	gpio26

Supported Thermistor Types

The thermistor port supports NTC thermistors (100K) by default. It is recommended to configure the 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 and PT100 require additional signal conversion chips and cannot be connected directly to the thermistor port.

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

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