Different battery and display (smaller)?

Has anyone managed to use a different battery and a different display panel using the connectors on the mainboard? I am aware that PD and type C display options exist, but that brings downsides. For a project, I need to use a smaller display and a smaller battery, but I don´t want to occupy two typeCs just to start it up. Also, using PD means windows can no longer read the power level nor recognize it´s running from battery.

EDIT: Can I use any 40pin eDP touchscreen?

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Using alternate screens through eDP is a bit of an open question. Here’s what I understand that we know:

  1. The mainboard side eDP connector is a custom pinout, but the screen side eDP is standard. You need to use the Framework eDP cable (or make an adapter).

  2. The mainboard was designed with touch displays in mind, and so the eDP connector has both USB and i2c signals on the connector. I would guess that a USB touchscreen is more likely to “Just Work” than an i2c one, but I don’t know that for sure.

  3. It is totally possible to go from the Framework’s eDP to standard DisplayPort, but because of the custom pinout, the right cable and/or adapter for the job might be difficult to source.

  4. It has been done to plug a regular DisplayPort signal into an off-the-shelf DP-to-eDP adapter and run the internal display standalone, and it Just Worked, which was surprising to all involved including the Framework team.

Here’s what’s unknown:

The power signals on eDP are standard pins, but it’s not known if they’re standard in terms of the power supplied, voltage, etc. It might plug in and just work, or maybe only some work, or maybe only screens with the exact voltage/current expectations and a compatible backlight control will work.

Everyone’s kind of nervous about trying because for the longest time before eDP, every laptop screen was pretty much custom, and it was nearly impossible to use a replacement with even tiny differences, even different revisions of the same panel sometimes.

Edit: Did some searching around, it seems like the few people who try this stuff say “It can work, just plug it in and see if it does, or else return the panel and try again.” As long as the connector is correct, that is.

As for battery… Easier said than done. The pinout is published, but the battery has i2c communications for status and monitoring, and I’m not sure how to replace that or if just hooking up a dumb battery with the same voltage but a smaller capacity would work.

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No, the 40-pin touchscreen-enabled eDP panel pinout is different from the 40-pin high-resolution eDP panel pinout. At least, some kind of pinout-altering adapter would be required, for sure, and you’d still need to get USB from somewhere.

As for the eDP situation, Paul’s summary is apt. I’ll add this - the FrmW-provided backlight voltage should be suited for most panels out there, and 3.3V for panel electronics is standard; the pinout, however, might not be compatible with smaller LCDs, as they tend to be 1080p or lower resolution, and smaller-resolution LCDs tend to be 30-pin, 40-pin for touch-enabled ones.

So Arya, is Paul right about that it “should work” if I use Framework custom 40pin EDP to regular touch 40pin EDP cable? Or the framework cable on the other side is not the touchscreen EDP?

To sum it up, right now we are talking about 3 kinds of 40pin EDP. Framework´s custom pinout 40pin EDP, high resolution 40pin EDP and touchscreen 40pin EDP.

I am dropping the battery idea then, I think there will be enough trouble with the display, so I´ll either use standard FW battery or PD. But as for the display, I really want it to use eDP instead of USB C. I still don´t have motherboard so I don´t hurry anywhere, I will probably wait until someone upgrades and sells their old one, as I don´t want to ruin myself building a project that might not work as intended.

For reference, the mainboard pinouts on Github:

Pin Signal Description
1 BL_POWER 12-17V backlight power
2 BL_POWER
3 BL_POWER
4 NC
5 GND
6 AUXP
7 AUXN
8 GND
9 EDP_TXP_0
10 EDP_TXN_0
11 GND
12 EDP_TXP_1
13 EDP_TXN_1
14 GND
15 EDP_TXP_2
16 EDP_TXN_2
17 GND
18 EDP_TXP_3
19 EDP_TXN_3
20 GND
21 EDP_HPD hotplug
22 BLK_PWM_LCD Backlight PWM
23 BLK_OFF_N Backlight Enable
24 NC
25 NC
26 3V_EDP 3VS
27 3V_EDP
28 3V_EDP
29 3V_TS 3VS for touchscreen
30 3V_TS
31 USB_DP USB
32 USB_DN
33 TS_EN
34 TS_RST
35 TS_INT_N
36 TS_SDA
37 TS_SCL
38 NC
39 GND
40 GND

And this is the pinout for a 40-pin eDP connector, 2-lane DP plus touch panel.

Interesting. It looks like the FW eDP is four-lane. After Googling around a bit, it looks to me like a DP source can have a scaleable link and can swap between 1, 2, and 4 lanes, but that depends on the design of the DP source. Since the source in this case would be… the Intel GPU’s display controller? I’m pretty sure that’s a good and full-featured design, since Intel is the main public source of DisplayPort design documents (as opposed to the member-only standards documents from VESA).

… Yes, the source is flexible, and the sink (i.e. the screen) communicates what it is capable of, and they negotiate a link. It seems to be a hardware (or at least firmware) design choice.

Hm. Upon information and belief, yes, the DP link does negotiate the number of lanes to connect.

Okay, so given all that, it looks like the Framework eDP plug is extremely full-featured, but perhaps with a bit lower current capacity because of the reduced pin count. I looked at a random LG 17" display panel, and the voltages on all of the pins look right…

Well, personally, I’m ready to try plugging in a screen. I don’t have one handy, but I would.

E: Oh, there is one difference: standard eDP touch screen interface is 5V power, and it looks like the FW connector is 3V. So check datasheets before plugging any old panel.

Framework has an eDP cable that goes from the mainboard to the panel. The custom pinout eDP connector is on the mainboard side, to be clear.

Such cable isn’t available at the moment, sadly. The only cable we currently have available is the stock one, which is framework custom to regular high-res 40pin eDP cable. Getting such cables built tends to be a tad expensive, at that, even though doable.

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OSHPark does flex PCBs, might not be too hard to create adapters…

So if I understand it correctly, there is no way to plug 40pin EDP touchscreen from some other laptop into framework laptop because the mainboard side is custom pinout and the cable, even if I manage to source one, is 40pin hi-res and not touch.

As I read through this thread, the conclusion is a custom pinout on motherboard, using FW cable ends in a standard 40 pin eDP, although there are different 40 pin eDP screens that get dived into 3 sections:

  1. lower resolutions but include touch
  2. higher resolutions without touch
  3. higher resolutions with touch - BUT this might be a higher pin count?

I see remarks above that the 40pin eDP is a high res version correct Arya?
I also see remarks the motherboard custom cable was designed for touch, but then the 40pin eDP could therefore contain both hi-res and touch? hmmmm… not sure on that?
I also see remarks the lanes for hi-res are all there and dependent on the intel driver?
I also see a remark the touch voltage of some panels is 5v but FW is 3v?
And while everyone is discussing it nobody has actually plugged in a different display? I would make my own lids if I could find a panel with a wider gamut of colors!
And the final question, although there may be lanes and wires ready on the motherboard, the FW cable may not include tough or high res additional eDP lanes?

yes, and to make it clear - this is the case for every single laptop out there. The mainboard side connector&pinout on all laptops is always custom, there’s no standard. The only part standardized is the panel-side connector type and pinout.

The standard Framework cable only carries 40-pin hi-res signals, no touch.

not at the moment. Better way to put it - we haven’t found a way yet :wink:

I haven’t seen evidence of such panels. The high-res-with-touch panels I’ve seen, have touch on a separate connector and use high-res 40-pin eDP pinout. Please do share if you found something (would love to put it here!), but as far as I’m aware, such panels don’t exist. So, 2 types of 40-pin eDP panel connectors, not 3.

Yes, the Framework eDP cable uses the high-res eDP pinout.

The FrmW eDP cable only carries high-speed data lanes to the 40-pin high-res panel connector, and doesn’t carry touch signals. It does carry all the lanes available - that is, 4 of them.

On the mainboard-side custom connector, there’s provisions for both high-res eDP (4-lane) and touch. The touch signals on the mainboard-side connector aren’t used in anything we’re aware of, except research from someone on Discord that I don’t currently have link for.

BTW, the mainboard-side connector happens to also be 40-pin! Confusing! I suggest we just call it the “mainboard-side connector”, omitting pin amount to avoid mixing it up with panel-side 40-pin connectors.

Yes on the former, idk what you mean on the latter.

Yes, for some, it seems that 5V is used as touch voltage. Regardless, this is the smallest of our problems at the moment, and is easy to work around.

Sure, find a 40-pin high-res (touch-less or with touch on different connector) panel and plug it in. Perhaps, check if the pinout’s matching, but it’s standardized enough that it ought to.

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Nuts, I was all excited to draw up an adapter board today but there’s no PCB-mounted mating connector for the eDP connector on the Framework mainboard. Until we can buy the cable separate from the panel, I think the panel may be the only screen we can practically attach, regardless of what could work in theory.

yep. That said, we’re looking for other options still - there ought to be a way around having to buy a cable separately somehow!

I think I saw a high-res panel with touch through a single 40-pin connector a couple of months ago (was it called touch-on-cell technology?), but the size of the panel was definitely not framework-compatible.

I’m very interested! do you recall which laptop the panel was for?

BTW, high-res => higher than 1080p, as a rule of thumb, I’ve always seen 768p use 1 lane and 1080p use 2 lanes, everything beyond that seems to go with 4. “Seen” and “seems” because my experience, while broad, is still limited. For instance, if a display does 5.4GHz lanes as opposed to the usual 2.7GHz (including the Framework panel), it could do >1080p over two lanes. There could be displays that have 5.4GHz support, it’s just that I haven’t encountered one yet.

Unfortunately, no.

I came across the listing by chance, searching for some completely unrelated spare parts for a microwave on ebay, aliexpress or other marketplace. It was shown as one of those intriguing “similar/related items” that makes you wonder how an algorithm could have connected those things. But mentioning on-cell (or in-cell?) touch 40 pin made me curious enough to click on the link.
As far as I remember, the panel was listed only under its panel model number (without mentioning a compatible laptop model or manufacturer) as new and only available for pre-order at the moment (not yet delivered? sold-out? wrong location?), it was larger than 14 inch (15.6 inch maybe?), had a “standard”-sized eDP 40 pin connector, 16:9 (or maybe 16:10) format, was LCD not OLED. The description mentioned a (for me) rather odd resolution higher than FullHD but less than 2560 × … and asked you to contact the seller with the complete model number (+ revision) of your laptop before ordering.

A later search for smaller panels with on-/in-cell touch revealed a number of “standard” 40-pin panels with a resolution of 1366 × 768 and some 1920 × 1080 panels with “narrow” 40-pin connectors.

Edit: I’ve found one discontinued UHD model with - according to panelook.com - on-cell touch and 4-lane 40-pin eDP connector that might have been used for a Dell 15 Inspiron 7559 (pictures don’t show an additional digitizer cable or connector at least). However, that’s not the one I stumbled upon 2 months ago.

Thanks Arya. I wasn’t aware touch was sometimes a separate connector. So when Framework says their laptops have touch functionality to be brought out later, that means not in the eDP connector correct?

What this does mean is that we can swap the display for different ones that may have a wider color gamut. I’m most interested in something that gets closer to adobe RGB or DCIp3. The 3000x2000 OLED looks interesting, does OLED cause any issues since most other screens are IPS? Power supply requirements might be in question for what framework supplies.

@Arya I found this panel on panelook.com and from the photos it seems to have only one 40-pin eDP connector and touchescreen support.

Going through panelook’s filters, there are no 3:2 hi-rez panels with touch support (using eDP port).

You do have the Microsoft Surface Laptops which do have 3:2 screens with ~1440p resolution and touchscreen but I do not know what connectors they use. Removing the eDP requirement from panelook still gives me no results…

I’ve also looked at other Microsoft Surface panels on eBay but they seem to use a 40-pin eDP connector for the actual display and 2 other connectors for presumably touch and (maybe) stylus.

Yes, if you are trying to get touch enabled, then you need to sort out how to get that part of the cable into a usb input I’m guessing. It is my understanding the eDP 40pin cable on the FrameWork does not support touch. It requires a separate connector from the eDP. So don’t get tricked into a 1080p screen with touch and an eDP 40 pin cable because that won’t work.