I found out about this Displayport connector that also lets you plug HDMI into it and was wondering if this would open the possibility for a 2 in 1 expansion card that would both support HDMI and Displayport the link to the connector I found 845-002-217CRL Rego Electronics | Mouser Europe
Anyone think a custom expansion card might be possible here, I’d like to hear someones thoughts on this, especially someone who knows something about the electronic circuitry needed.
It would definitely be very great if we could just have 1 expansion card for both HDMI and Displayport.
I think it is possible, however I have my doubts about the durability, spec compliance, and signal integrity of such a connector. Potentially causing reliability and/or performance limitations.
Just like any other USB-C to HDMI adapter, what @Michael-R is proposing would use DisplayPort over USB-C to get the display signal and then use an active converter chip to translate that into HDMI signals where needed.
That’s how I thought that could work as well, but I see the potential problems and implications with this, for example I wasn’t sure how possibly switching the signal provided to the pins would be.
Still it would be interesting to see someone give it a try and tell us how it goes, if it’s possible.
If not that’s ok as well, as I’m currently not actually in need of such a card and swapping expansion cards isn’t a hard task after all, it seemed like a cool idea that could be practical for others though.
https://www.youtube.com/watch?v=rZpHizpZSPQ saw this video recently and thought it would be a good idea to share it here, i looked around for a bit to see if you could try and just buy the port but couldnt find anything
I saw that too, it’s genius but seems to need more than just a physical port, looks like it needs logic somewhere, doesn’t mean such a module is impossible.
I think this might fail due to the same reason such ports only appearing on niche prototype-ish machines like this: the entity behind HDMI most likely wont allow it since its a proprietary standard. Still would be awesome if there would be a kit to convert DP Cards or the dead DP cards that Framework sells on the Marketplace into this combo port, since this could maybe go around this licensing issue.
The connector is still being sold, with data sheets giving the pinouts and the extra pin 21 which is used to detect whether you have a HDMI or DP cable plugged into it.
Would require some switching circuit and a converter for HDMI and from what I’m told they’re unsure about signal integrity
See my post for the link to the connector and the conversation about the feasability of such a card:
For the full size cables, I think you could probably use some simple logic based on the pins connected and have the card itself function as both HDMI and DP card. When a DP cable is plugged in or present at power on it causes the card to do a disconnect and reconnect presenting as a DP card/pass through and for HDMI, it does the same but as an HDMI card.
With all that, does the framework laptop support the older hdmi alt mode? If so, you could probably do away with the disconnect event if your’re fine with a lower HDMI standard.
Not sure if this approach would be worth adding for a USB C output version, as it might cause issues with docks (and how many devices do USB C HDMI in without DisplayPort support?).
I doubt the framework laptops support hdmi alt mode, we’ll probably need the same logic as the hdmi expansion card for hdmi and then maybe (correct me if I’m wrong) a mux to switch between displayport and hdmi mode depending on what pin 21 of the connector reports?
At least that’s what I assume how it would be done, I have zero clue about designing electronics like this unfortunately and couldn’t find anything about a circuit that can do switching between both hdmi and displayport signals.
Afaik no HDMI alt mode laptops or hardware was ever mass produced.
HDMI alt mode was limited to an outdated version of HDMI when it released and supported less than a third as high bandwidth as DisplayPort alt mode did at the time while also supporting far inferior compression methods (compression helps to take much better advantage of the limited bandwidth, so lacking good compression added insult to injury). So it never really saw any use.