RPi-ATX-LCD-Breakout

This board allows you to connect an ATX power supply and a HD44780-comptible LCD screen to your Raspberry Pi (or others with compatible GPIO layout).

While it does have a 40pin GPIO connector, it will also work with older 26-pin variants of the Pi.

The board was created to provide a convenient interface for two Octoprint plugins: PSUControl and LCD-HD44780 (See links on bottom of this page).

The board itself offers a variety of features:

Powering the Pi using +5VSB (standby power)
Switching the PSU on and off using GPIO Pin 12

The GPIO pin can be connected to PS_ON directly, or via a transistor. This is choosable using the three-pin jumper switch.

Alternatively, the PSU can be forced to be on, by using the 2-pin PS_ON jumper.
Connecting a character LCD to the Pi

LCD is wired as follows:

Register Select

15

Enable

16

Data 4

21

Data 5

22

Data 6

23

Data 7

24

Data 0-3 pins are not connected. Read/Write select has been wired to GND, so it's not possible to read data from the LCD screen. Contrast pin is connected to a potentiometer.
Allow connecting of two fans, one 5V, one 12V
Providing screw terminals for GND, +12V, +5VSB and +5V
Providing a USB outlet powered by +5VSB

Note: All pin numbers use BOARD numbering.

Links