OLI (Open LCD Interface)

Open Source interface to connect LCD's (5" and 7") to any Board/Micro-controller using HDMI and SPI

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OLI is an open source solution for using an LCD (5 inch and 7 inch) with both HDMI and SPI with almost any board or microcontroller. The objective of this project is to create a tool that is flexible and that allows the use of a single LCD instead of having to have a different LCDs for each development board. This solution could be used for example by an arduino board and raspberry pi.

OLI consists of two parts, a main board with the LCD, power circuitry, GPIO interface to a microcontroller and a connector to attach a video module board that has the HDMI (yellow board) video controller or the SPI (red board) video controller. The other part of OLI are the individual video controllers, the design is made such as you can remove the HDMI video controller and connect the SPI and vice versa to adapt the LCD to the development board / microcontroller that you are using.

  • 1 × Base Board for LCD PCB with power circuits, LCD connector, Video module connector
  • 1 × SPI video module (red board) SPI to LCD graphics processor board, based on RA8875
  • 1 × HDMI video module (yellow board) HDMI decoder pcb with touch to USB chip

  • 7 inch and 4.3 inch boards ready

    Joe Mendia05/30/2016 at 21:55 0 comments

    I have been a bit busy these days but I managed to solder the base board for the 7 inch LCD and another 5 inch base board for further testing. One good thing about this project is that the base board for the 5 inch LCD can be used with a 4.3 inch LCD with no modifications at all.

    Here you can see the 7 inch being used with a Raspberry Pi Zero, the Arduino was wired for other test and left there.

    Here for a size comparison I show you all the LCD's I have tested, the top one being used by the Raspberry Pi zero is the 5 inch with the HDMI module (yellow board), the 7 inch is on the left used by the arduino and the one on the right is the 4.3 inch used with the arduino. The two LCDs connected to the arduinos have the SPI module on the back (red board).

    Next I show you here a small side by side test run with the 3 LCD's working together, the touch screen is working with the SPI video module (red board) but not yet with the HDMI board, that is one of the next steps. If you see the detail picture of the yellow board, you will see some missing components that are there to translate the touch screen to USB.

    I found some image quality issues with the 7 inch base board, I think the length of the H_SYNC, V_SYNC and color lines is the problem. With the SPI video module this is not an issue because the frequency is much smaller than with the HDMI, a detail to take care for the next version of the base boards.

  • OLI first test

    Joe Mendia05/25/2016 at 18:59 0 comments

    Here I show you a test using the first OLI board with a 5 inch LCD using an Arduino UNO and a Raspbery Pi Zero

  • Origin and explaination of the OLI

    Joe Mendia05/24/2016 at 23:03 0 comments

    Here I explain the OLI in detail

  • Base boards for 4.3", 5" and 7" Screens

    Joe Mendia05/15/2016 at 18:32 0 comments

    Once the proof of concept of OLI worked was time to separate the circuits for 40 pin LCD's (4.3 and 5 inch) and 50 pins LCD (7 inch). The initial base board had the power circuitry for both types of LCD's. Now with these new PCB boards the power circuits are separated and now will be possible to test individual sizes of LCD's with the diferent video modules (SPI module and HDMI).

    LEFT:PCB for 40 pin LCD's, RIGHT: PCB for 50pin LCD's, TOP: 5 inch LCD

    The next step this week will be to populate the boards and start making tests!

  • OLI proof of concept

    Joe Mendia04/26/2016 at 16:54 0 comments

    After clearing the idea of OLI and in order to proof the concept I designed the first base board to be used to test the modular design behind the OLI.

    Here is the first board with the power circuitry soldered by hand.

    This board was made in order to generate the different voltages (3.3V, 4V, 10.4V, 16V, 24V and -7V) needed by the 7" LCD and to break the 24 RGB signal to a connector to attach the video modules.

    For the video signals, two PCBs were also made, the yellow one is a HDMI decoder based on the TFP401A and the red one is based on the RA8875.

    The test of the yellow one with the base board can be seen here:

    The HDMI signal is from my laptop showing an image, the quality is quite good. Based on this tests I have concluded that the concept is feasible and will have to refine the base board design.

    Here you can see a video testing the 5" LCD with a HD Video from youtube. The 40p connector to the LCD in the main board has a fault and the colors are not nice so I have connected it to the 50p interface of the base board and it works great.

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HecatronsWorkshop wrote 05/28/2016 at 21:30 point

Is the LCD interface LVDS? What I'd really like to see is an HDMI or SPI Input but then that converted to eDisplayPort for a retina LCD (spare ipad retina screens from ebay)

  Are you sure? yes | no

Joe Mendia wrote 05/28/2016 at 14:00 point

This one works good with HDMI boards but you can not display data to the LCD using an arduino or a teensy for example. The arduino chip on the watterott board is for writing the EDID and the touch interface

  Are you sure? yes | no

x893 wrote 05/28/2016 at 14:18 point

Yes, i wait board on RA8876 or RA8877 (currently use RA8875) for 14"-15" panels from old notebooks. May be you know chips to split HDMI signal to some panels ? For example - for computer HDMI looks as 960x800 pixels and connect two panels (RGB/LVDS) with 800x480. Or split RGB signals to 2 panels (or 4 :))

  Are you sure? yes | no

Joe Mendia wrote 05/28/2016 at 17:49 point

I think for that you need an FPGA

  Are you sure? yes | no

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