30-pin eDP connector and Laptop LCD Panel

[WZ9V]

Can the 30-pin eDP connector be used for a 1920x1080 Laptop LCD using a 30-pin eDP?

[technicrat]

Hi,
that is a good question. I'm interested too.

I found Displays like: https://www.sdv-elektronik.de/lp156wf4- ... splay-matt
But i need to know if this is working

Thanks

[technicrat]

Hi,
that was a good question. I'm interested too.
But i need to know if this is working

I have found Displays like this:
https://www.sdv-elektronik.de/lp156wf4-spl1-15-6-slim-edp-ips-full-hd-display-matt

Thanks

[v8dave]

You can do this but you will have to use a custom kernel to set the timing of the display.

If you want touch, you'll also need to add a driver for this if the touch controller is not one supported by the kernel.

You'll also need to know the LVDS bit allocation applied to each channel for your chosen LCD. It is likely 24 bit as that is most common so will be spread across 3 LVDS channels with the remaining timing signals on the 4th channel.

[technicrat]

In my opinion, it is a heavy task to build the own custom kernel.
especially if you want to use android on the T4.

I suspect that most display manufacturers are not interested to corporate with us and get us details about the display and their time rates.
So it's sounds like a try and error session.

Is there a guide to build a new kernel for the oreo android image for T4?

for my project the displayframe uses an 3M micro touch controller and has an option listed for a mainline kernel.

thanks a lot

[TamiDuke]

Hi..most laptop screens use a 30-pin eDP connection. The back of screen has PCB assembly configured like that, to connect such type of connectors. If you would like to use this for one of your projects, you need a controller board for that specific screen. This will give you an HDMI input - which you can use with your Raspberry Pi 3 HDMI output.

[technicrat]

Hi TamiDuke,

why should I use a hdmi controller to connect a Display with the nanopc.
That would mean that the eDP interface is useless.

The way is to connect the Display over eDP without Controllers. The advantages are that I have no external power supply and no special controller.

Interesting is how to adjust the software so that the display works correctly on the eDP connection

thanks

[v8dave]

The file to which you need for the LCD timing is /kernel/drivers/gpu/drm/panel/panel-friendlyelec.c under the android source.

In here you can find the LCD timing for the HD702E

The eDP panel doesn't appear to use the normal 1-wire for touch or LED backlight control and instead is over I2C with GPIO for interrupt and reset. Backlight is via a GPIO for on/off and another with PWM.

I've still to find the setup for the eDP output itself.

What this means is that you could develop your own PCB to interface from the T4 eDP connector to your LCD and make changes to the kernel timing. Bit of work but it should be possible if you have the PCB and coding skills.