The Ender 3 display is based on the open Reprap screen design, but includes a header called EXP3 that allows for communication with a single cable. This header communicates with the display over SPI, but the documentation I could find online was sparse and conflicting. I verified the pinout and created this graphic to document this header’s pinout.

This display uses the ST7920 controller. The arduino library u8g2 has support for it.

Graphic explaining the pinout. Textual pinout below

Text Documentation for Accessibility

The notch on the display board is on the top. Pins are left to right.

Ground Chip Select Knob Rotation Knob Rotation 2 Beeper
5V Data Clock Unknown Button

SPI Pins

  • Chip Select
  • Data
  • Clock

Digital Buttons

  • Knob Rotation 1
  • Knob Rotation 2
  • Button