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RepRap Touch TFT LCD (mini Pronterface style)

Control your RepRap 3D printer with a touch

Another LCD for Marlin firmware?
Yes, my Melzi board is equipped with a atmega1284P, the only free pins (with 2 extruders) are TX1 and RX1.
This is perfect for a serial LCD like 4D-Systems uLCD-32PT. or uLCD-32PTU


  • Work in standalone mode, no PC is required
  • Intuitive Touch Interface, no external button is required
  • Graphical interface “Pronterface” style
  • Show SD card file content, print the selected file,Pause/Resume.
  • Move X,Y,Z axis with a touch
  • Show Temperature and Target Temp up to two Extruder
  • Extrude/Reverse Filament functionality (Settings mm and mm/min)
  • Set HotEnd Target Temp
  • Set Bed Target Temp
  • Zprobe and Z offset functionality
  • Wav Sound to notify the end of print with a built-in speaker
  • Only two pin for communication (TX1,RX1) ,perfect for Melzi/Sanguino board
  • Works with a few changes to the Marlin firmware

This project is no longer supported, is not recommended in the latest versions of Marlin or new machine.

Manage Extruder & Bed

Through a Slider, or two incremental buttons can be set :

  • Teperature of the two extruders
  • Bed temperature
  • Length of filament to Extrude/Reverse
  • Extruder Feedrate

Manage SD Card

Through the SD-card menu you can select a file to be printed, stop or resume printing.

Manage Z offset

The Z-menu allows you to enter an offset to calibrate the Z-home.
A button Z-Probe was inserted to allow you to probing the bed where the firmware allows it.

This case is only compatible with the uLCD-32PT

many users have adapted for the uLCD-32PTU models:

RepRapPro version:

Prusa i3 version:

MendelMax version:

Marlin firmware modification

This LCD works in standalone mode, it has an internal PICASO microcontroller.
The entire Graphics interface is not managed by Marlin Firmware but the PICASO micro.
My PICASO firmware send commands through the GCODE protocol to RepRap main board.
The communication is done by a second serial port.

The main microSD that contains the gcode file is managed by the RepRap motherboard. Gcode file is parsed by the RepRap motherboard and not the display firmware!

A few changes are necessary for the Marlin firmware.
I added the LCD support code to my reprappro Marlin branch:

git clone git://

uLCD-32PT Firmware

The firmware to upload into the PICASO microcontroller is located in my github repo:

git clone git://

Upload the firmware on uLCD-32PT

This procedure shows how to compile and upload firmware on Picaso uLCD-32PT or uLCD-32PTU
Unfortunately, the 4D-Systems development environment only Windows supports. :(

What you need to start?

  • a 4D-Systems Display uLCD-32PT or uLCD-32PTU
  • a microSD card for display formatted with FAT16 (256Mb is fine)
  • a FTDI usb to serial converter (or equivalent)

Upload the Firmware

  1. Download and install the 4D Workshop4 IDE Tool.
  2. Connect your LCD using the FTDI cable to the PC.
  3. Copy the entire contents of the directory CopyToSD in the microSD.
    This is a precompiled image control database, if there are no changes to the graphical interface you can use these precompiled files.
  4. Plug the microSD in the Display.
  5. Open the 4D Workshop software and set the Display Serial port.
  6. In the option tab, select FLASH destination ( otherwise the displays return error 8)
  7. In the workshop open the file Main.4dg located in the root directory of my project, press the Compile & Download button.

At the end of the upload the mini pronterface graphical interface appears in the display.
The display is ready to work!

if the Graphical interface does not appear correctly, the problem can be caused by microSD.
Try to reformat or use the 4D-Systems Removable Media Partition Edit Tool


, 2014/01/06 01:06

no, only the 4D-Systems uLCD-32PT or uLCD-32PTU display is compatible.

, 2013/10/15 21:36


is this possible with three Extruders?? I think the proplem would be to “show” the three Extruder temperatures?

thanks for help


, 2013/12/04 20:47

Same question as Tobias: does anyone have an experience with a three colour mendel? How about the connection, since a couple of the connectors are used already to drive the slaveboard?

, 2014/01/06 01:04

Mendel 3 colors is not ompatible. The serial port required for the display is occupied by the slave multi extruder board .

, 2014/02/18 17:05


I would like to know the schematic connection of the LCD that I want to connect to a rambo.


, 2014/02/18 17:03


I would like to know the schematic connection of the LCD that I want to connect to a rambo.


, 2014/04/21 15:03


The sketch appears to be too large for Melzi, 82322 bytes (of a 63488 byte maximum).

Perhaps I'm doing somethings wrong?


, 2014/04/21 20:42


I'm receiving an error where the sketch (~83k) seems to be too large for the melzi (~65k).

Am I doing something wrong?



, 2014/06/10 17:09

Once you load the firmware to de Picasso controller, connect the tx and rx to the ramps and that is all?

i mean, it's neccesary modify the marlin firmware?

Sorry for my english!

, 2014/07/23 21:12

Why do say you display is not compatible with latest marlin and new machines?

, 2014/10/06 00:03

PLEASE NOTE, all hard links above may no longer work as they are out of date.

To download the Workshop4 IDE, please navigate to the 4D Systems website and the Workshop4 Product Page:

Direct Download for the latest version of the IDE:

Most other documents listed above are easily found on the Workshop4 Product Page.

I have emailed the site owner already and asked him to update, but no response yet.

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reprap/lcd4d.txt · Last modified: 2014/06/18 22:59 by marcoantonini