RGB2HDMI won't work with flat flex cable

[spacebiscuit]

I've setup the RGB2HDMI mod on my Amiga 600. If I plug a mini-hdmi cable to hdmi between the pi zero and my monitor all works fine. But I want to use a flat flex ribbon cable from the pi to the amiga case where the rf modulator is (to be removed). With the ribbon cable however I cannot get any output.

I had assumed the cable was faulty, so I replaced it without success. I then came across this post which reports the same issue:

https://forums.raspberrypi.com/viewtopic.php?t=336732

Also note that in this tutorial Jab Beta reports the same issue believing that a broken clip was the reason for no signal, he plugs the hdmi direct to the pi as a workaround:

[ Show youtube player ]

So I'm wondering if anyone actually has the flat flex cable working? Maybe the issue is mini-hdmi to hdmi? Maybe the emle adpater should be a mini-hdmi rather than a full size adapter?

Any thoughts?

[jbilander]

Hi, it works for me with a short 15cm flat flex one. Did you try and fiddle with the hdmi boost setting?

There is a setting in the config file that can help with cable issues

I have it at default value which is 5 I think.

https://stardot.org.uk/forums/viewto...341298#p341298

[solarmon]

@spacebiscuit

What are the HDMI connectors/adapters and flex cable are you using?

There are different types and variations of the FPV HDMI adapters.

It is important to know what orientation the connectors and adapters are.

For example, on the flex cable - are the connector contacts on the same or opposite sides? And on the HDMI adapters, whether the connectors are 'top' or 'bottom' facing?

EDIT: I have also noticed that certain FPV HDMI adapters have different pinouts, so that is another reason why it may not work, and can be dangerous if the power rails are connected together if you use the wrong adapter.

[spacebiscuit]

Thanks for the replies guys, the hdmi adapter that I am using is slightly different to the adapters I have seen in photos and video tutorials. Noteibly the retaining clip is hinged and pivots down to lock the cable. In the video I have seen the retaining piece pushes into the adapter.

I have the fatter wider adapter also and if I use that I have a signal, the only issue is that it does not fit the 3D printed housing that I have.

The photo below shows the two adapters, the one I need to use is the one on the right. I am inserting the cable with the contacts face up as shown in the photo.



I did read about the config setting but since I had it working with the other adapter I assumed that this is a hardware not software issue?

[solarmon]

Yep, this is the same issue I have come across.

The 'fat' FPV Type A HDMI adapter has a different pinout to the 'slim' FPV Type A HDMI adapter.

The 'fat' FPV Type A HDMI adapter has the contacts on the TOP side, but the 'slim' FPV Type A HDMI adapter has the contacts on the BOTTOM side.

The 'fat' FPV Type HDMI adapter has the same pinout and same TOP side contacts as the Type C mini HDMI you have, that is why it works with that.

I've still to find a combination of adapters that allows me to use a 'slim' Type A FPV HDMI adapter. It's obviously possible, it is just that I haven't found a source for this permutation.

[spacebiscuit]

Stupid question I guess, but if contacts are on the bottom side why doesn't it work when the cable is attached with the silver cable contacts pointing down rather than up?

Failing that would it not just be a matter of just speaking to the seller to request a correct compatible male hdmi adapter for the other end of the ribbon cable?

HNY BTW

[solarmon]

HNY!

If the pinouts are different (totally different, not just flipped/opposite) and don't match, no matter what permutation of cable you have, or flipping of connectors/cables, it will never match. If the power rails get connected (i.e. +5V with GND) then that can cause damage to both ends.

[jbilander]

Probably pinout becomes wrong then.
If you can't find a compatible slimmer one I think it should be fairly easy to make your own PCB in KiCad (with the correct pinout) and use these 20P connectors, they are the same pitch and would fit the Flat Cable fingers.

https://www.aliexpress.com/item/10000000478377.html

[maneus]

If it dosnt work with the white field showing up on top of the cable, try to turn the cable, so the white field is showing down when klipping into the adapters.

That worked for me. I first attached it the wrong way into the adapters, so my monitor noticed a connection, but showed nothing.

[spacebiscuit]

I've spoken to the vendor, I'm going to order their male mini-hdmi connector and cable to ensure compatibility, I'll report my findings once I know and can confirm it works.

[spacebiscuit]

So the new female hdmi connector that the vendor supplied arrived with a new compatible cable and it works perfectly - interestingly the silver contacts on these goes into the slot facing down - the others I tried were the opposite.

This smaller adapter fits perfectly into the 3d printed caddy, i added a dab of super glue on the underside to hopefully keep it firmly in place