ender3-lcd-arduino

This is a simple tutorial on how to reuse old LCD boards from Ender 3's with a microcontroller such as arduino or teensy

Pinout

The entire board can be controlled via the EXP3 10-pin connector The pinout on the EXP3 is as follows

        ------
BEEPER |10  9 | ENC
   EN1 | 8  7 | LCD_CS0(?)
   EN2   6  5 | LCD_SCK
LCD_CS | 4  3 | LCD_MOSI
   GND | 2  1 | 5V
        ------

Note that pins 6, 8, and 9 are floating when true, so use a pullup resistor to get a clean input

Rotary Encoder + Button

The rotary encoder is standard incremental button/encoder and can be controlled with a library such as Encoder.h The ENC pin (9) is for the built-in encoder button

LCD

The Ender 3 LCD uses an ST7920 128x64 or equivalent driver. A library, such as u8g2, can be used to control this The LCD_SCK (5) is used for clock, LCD_MOSI (3) is used for data In/Out, and LCD_CS (4) is for Chip Select/Register Select