40pin eDP (Framework/4Lane) to 30pin eDP(2 lane)

Creators & Developers Mainboard
#1

Hi,

I have been doing a bit of research in to this and I am super doubtful this is possible, primarily because there are no existing adapter boards that do this… and if it were possible you would expect there to be. What is super frustrating is how many LVDS/HMDI/DP to eDP adapter type boards there are, but this seems to be missing.

I would basically like to attempt to drive an LCD that is 2 lane 30pin eDP from the motherboard. Now that you can get the cable from Framework connecting a third party 40-pin display should be relatively trivial (so long as it adheres to the standards).

From the pinouts on the 30/2 and 40/4 eDP connectors it looks like you should be able to just wire up the 30pin to the correct lanes in the 40 pin - but I can find no reference of anyone doing so online.

So I’m just making this topic to see if anyone here who is a little more familiar with the standards can weigh in as to why this isn’t possible, or if there are any other solutions (short of using a separate driver board - which is my current solution, but it dumps unwanted heat into the enclosure I’m making and takes up far too much space)

Edit: Also, if anyone has the datasheet for the 13" Framework panel (NE135FBM-N41.pdf) I would love to have a look, it’s a paid download on Panelook which is a shame.

Managed to get some credits on Panelook with my business email, downloaded the datasheet which I have shared here:
https://drive.google.com/drive/folders/1BMfjR-PTisAMooNburfTxSmL2k8WWXbI?usp=sharing

edit: So… short of the knowledge as to why this probably wont work I went ahead and designed an adapter on EasyEDA and ordered some boards. I have a couple of ‘spare’ displays from this ongoing project so if I fry one it’s not going to be the end of the world.

I fully expect someone is going to come in and tell me that I just wasted the time/money/effort in doing so, but what can I say… I’m inpatient :joy:

5 Likes
#2

There’s nothing I can think of that would prevent it from working.

2 Likes
#3

Now you’re getting me all excited!

1 Like
#4

Ive been poking through similar topics myself as well, the biggest issue with using a premade 40 pin to 30 pin adapters is that apparently, there are two different 40 pin edp connectors, one for high res screens (what framework uses) and one for touch screen enabled screens. Apparently from what I’ve read, the two arent pin compatible

it really blows my mind how loosey goosey a lot of EE “standards” are

#5

Yea I had read that… However the info I had read was that Framework were actually using the video+touch pinout, but that they just didn’t connect the touch.

But either way the total guess that I’m going on here is that both types of 40-pin have the relevant pin outs for a 1080 screen, so by connecting those and just leaving the ‘extra’ ones unconnected maybe it will work…

Who knows. I have my main board now and my adapter board from jlcpcb should be here in a few days. So we will find out if I kill a screen. I don’t even want to think about killing the main board :see_no_evil:

#6

Just want to check, you used the display side connector pinout, correct?
Display side: https://github.com/FrameworkComputer/Framework-Laptop-13/tree/main/Display#pinout
Motherboard side: https://github.com/FrameworkComputer/Framework-Laptop-13/tree/main/Mainboard#display-interface

#7

Yes indeed, actually just used the datasheet I found above for the pin out to the panel, but same difference.