Awesome project and writeup!
Looking forward to seeing your progress.
How did you reverse engineer the pinout? Did you watch the signals live in the original system or were you able to do it just from the digitizerd board?
To reverse engeneer the pinout I measured each pin with an osciliscope while the digitizer board was in the origonal system. I also measured the pins on the original system without the board connected in order to figure out what signals were sent by the computer to the board and what pins needed a pullup resistor. I do not think I could have figured out the pinout without the original system.
Furthermore, the modifications I made to the frameworks APCI table in order to get the OS to recognize the digitizer were only possible beacuse I could extract and decompile the APCI table from the origonal system.
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Thanks!
Out of interest, what are your plans re form factor? Do you plan to design a custom chassis?
I personally would be quite happy even with a pen-and-touch screen in the original framework clamshell form factor. I looked around for screens that would fit (13.5" 3:2) and there are not many. Originally I thought HP Dragonfly G3/4 would be good but they seem to not support pen input. The only ones I found so far that are 13.5" 3:2 (did not check the exact dimensions yet) are:
- HP Dragonfly Folio G3
- HP Spectre x360 14-EA (and possibly other submodels)
Another annoying thing is that most commonly you can buy laptop touchscreens without digitizer board, or you can get a whole laptop / whole lid, but then the display is often hard to separate from the lid (in 2-in-1s often glued in place and hard to remove without breaking it)…
Finding a touchscreen display that would work with the existing chassis would be awesome!
I am planing to make a 15in sized 2 in 1 with a custom chassis from machined aluminum and 3d printed parts. For ports I am planing to place usb-c hubs between the motherboard and outside edge.
I also ran into the issue of very few display options and lenovo was one of the only brand that I could find replacement displays without buying the whole lid.
For this project [Project&Inquiry] Framework 2-in-1 there is interest in finding a 13in touchscreen display that can be made to work with the framework so you might want to keep an eye on that as well.
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Also re disabling trackpad. Trackpad and touchscreen did not work together when sharing an interrupt line? Or you disabled it right away and did not even try that? Because in my experience, often it is possible to have two I2C devices sharing an interrupt line (albeit my experience is with much simpler devices such as GPIO expanders).
I never tried having them share an interrupt in software as I found that the trackpad its self actively drives the interrupt line high as well as low and because of that the interrupt pin on the touchscreen controller would only bring the voltage on the pin down ~2.5v when active which was not low enough to cause an interrupt. I though about putting a nor gate between the trackpad and the motherboard to allow for both to use the same interrupt but I got the interrupt pin on the eDP connector working first so I never explored that further.
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Sure, makes sense. I was wondering whether one could do this without messing around with the eDP cable (either using the existing one for a 40pin screen or buying an off-the-shelf 40-to-30 pin adapter) but this makes it seem more complicated.
If you can find a substitute for, or emulate, or don’t need the reset pin on the eDP connector you may be able to make it work without messing with the edp connector as there is another exposed interrupt pin on the camera connector that is used for the ambient light sensor. You probably have to disable the sensor if you assign it to the touch screen but it could be an option
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I had been looking into that. But from the block diagram at the beginning it seems that the ALS I2C is connected to the EC only (so I presume the same would be true for the interrupt)…
Maybe a custom eDP adapter will be the easiest way in the end. There also seems to be another USB2 on the eDP that one could break out and use for something else internally…
That makes sense, I forgot that the EC has its own i2c capabilities.
I think that an eDP breakout is likely the way to go and I recently finished the design for and ordered one that passes through the display signals to a noarmal eDP connector and breaks out all the touch signals to test pads.
I haven’t received it yet so I have no idea if it works but once I receive it, solder it together, and hopefully get it working, I will make a fourm post about it and finally get around to making a github repo
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The display and touch screen work!
This is the first PCB I have actually seen through to production so I am extremely excited that it worked on the first revision. I was worried that soldering the connector for the cable that goes to the framework motherboard was going to be nearly impossible after seeing it in real life (usb-c cable for scale).
Fortunately, with some #4 mesh solder paste, a hot plate from ebay, and a fair bit of patience when applying the paste and aligning the part, it soldered correctly on the first try.
With it soldered together I connected it to the motherboard, trackpad, and display. To my amazement, the display powered on and worked perfectly first time. I am extremely glad it all worked and I think I have used up all my good luck with how well it went.
I also finally made a GitHub repo and put the PCB files and dsdt files there.
The next step is to get the i2c port on the motherboards display connector working. So far Thomas_Makin and I have put in a bit of work and it appears that the eDP i2c connector goes to the embedded controller so it will not be a trivial problem to solve.
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Hello,
I’m working on a similar project using a display that has a wacom digitizer, it uses the same style 10 pin connector for the I2C interface, I was wondering if you found what these connectors are and if they’re available in a generic variety. As far as I can tell they’re made by I-PEX but I haven’t been able to find much in the way of premade cables that could easily be purchased for use in a project like this.
I was not able to identify the exact connector used but premade cables exist. If you search “lenovo samos flex5-15 cable” on ebay you will find cables like this one that fit the connector on the digitizer. I just cut the other side off and soldered the wires to my PCB but I assume that finding a connector that fits the other side would not be that difficult.
Thank you for this! One further question though, how wide is the 10 pin connector on this cable? I ask because on my digitizer, it uses a smaller 10 pin connector, and has a short extension cable that terminates with the same style 10 pin connector, but in a larger size.
The smaller size I need is about 6mm from edge to edge which includes the black plastic on either side bordering the pins. The larger size is 7mm from edge to edge.
Also perhaps this is the style of connector? CABLINE V 20345-010T-32R 20346-010T-32R 0.5 mm pitch, Horizontal mating type micro-coaxial connector
I have been unable to find these sold as components though unfortunately, seems you have to order the cables custom made.
I measure 6.44 mm on the pins that slides in and 7.21mm on the plastic arround them so I think it is the larger version unfortunately.
the connectors you found do look right to me but i also ran into the problem of very few premade cables avalible. You could search ebay for the laptop you have followed by “touchscreen cable” and see if anything shows up but becides that I dont know how to get cables for these connectors.
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Oh actually it looks like it’s the same connector, I measured with my calipers and got 6.39mm at the same point you did, the larger one measured 7.48mm at the same point.
What’s odd to me though is the difference in used pins compared to the pinout you found:
My particular display is from a Panasonic Toughpad FZ-G1 that was made sometime around 2014 based on the dates on the other components on the display.
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Hi!
I was thinking of a similar project, since im going to go studying soon and wanted a laptop in the form factor of MS surface laptop studio, but the reviews are mediocre and ive had bad experience with surface devices in the past and i really want a framework laptop instead.
I was just about to ditch the idea since it might be too complicated electronically but after seeing this post and seeing how recent it is, I cant stop thinking of it!
I immediately signed up to the forum and I’d be down to ordering a framework laptop and the display panel just for this project to maybe help design a case for it in the style of the MS surface laptop studio (which, in my opinion, is more convinient to switch between laptop mode and tablet mode).
I’d love to colaborate and make it a real thing!
I would love to collaborate on building out the project. There is [Project&Inquiry] Framework 2-in-1 that you might be interested in as well.
I’m going in another direction. trying to make a 17" 2in1 tablet/cyberdeck in a pelican 1490 case. I took the screen out of an inspirion 9700 4k 16:10 17". I just need to get the touchscreen working.