Strange thing, my FPGA HDMI output cannot work with cheap chinese HDMI Extender

Started by September 22, 2018
I bought HDMI extender over optical fiber for $125, from Alibaba.

HDMI Extender works well when Source is my laptop, but when source is my FPGA
board,there is a problem.
I enabled  TMDS, HPD, DDC, 5+, ground as in Hamsterwork's project  , it doesnot
works,I dont know why? Who had the same situation ? What to do ?

Alibaba seller know nothing about this, but they always tell me they manufacturer,
and cannot help me, i think just reseller sit there, and there no technical
support.
On Saturday, September 22, 2018 at 11:09:02 AM UTC-4, abi...@gmail.com wrote:
> I bought HDMI extender over optical fiber for $125, from Alibaba. > > HDMI Extender works well when Source is my laptop, but when source is my FPGA
board,there is a problem.
> I enabled TMDS, HPD, DDC, 5+, ground as in Hamsterwork's project , it doesnot
works,I dont know why? Who had the same situation ? What to do ?
> > Alibaba seller know nothing about this, but they always tell me they manufacturer,
and cannot help me, i think just reseller sit there, and there no technical support. Yeah, you got that right! I've written to Ali and eBay vendors for more info on a product and the response is nearly always that the info is in the listing... even when it is not. The vendors are probably like what we in the US call "fulfillment centers". All they do is post the listings and ship the products. A couple of times I've returned items explaining that they don't work right in some way and the vendor has asked for details to feedback to the factory, but I think this was more so they could get a refund. In one case it was a laptop battery that was slightly oversized so it wouldn't fit properly into the laptop without forcing. At $50 I expected them to ask me to return it, but no, they just wanted details so they could get their refund from the factory. Rick C.
On Saturday, September 22, 2018 at 11:09:02 AM UTC-4, abi...@gmail.com wrote:
> I bought HDMI extender over optical fiber for $125, from Alibaba. > > HDMI Extender works well when Source is my laptop, but when source is my FPGA
board,there is a problem.
> I enabled TMDS, HPD, DDC, 5+, ground as in Hamsterwork's project , it doesnot
works,I dont know why? Who had the same situation ? What to do ?
> > Alibaba seller know nothing about this, but they always tell me they manufacturer,
and cannot help me, i think just reseller sit there, and there no technical support. I meant to ask, does your FPGA work with the target without the extender? I assume you've checked this. If so, I'd say ask for a refund and try to find a name brand extender even if it's three times the price. If your FPGA design works with this then the cause of the problem is obvious. Rick C.
abirov@gmail.com wrote:
> I bought HDMI extender over optical fiber for $125, from Alibaba. > > HDMI Extender works well when Source is my laptop, but when source is my > FPGA board,there is a problem. I enabled TMDS, HPD, DDC, 5+, ground as in > Hamsterwork's project , it doesnot works,I dont know why? Who had the > same situation ? What to do ?
It might not support EDID, or might not safely transmit it over a long distance. Result is that the source can't detect what resolution to send. You can either disable EDID in your project, or use an EDID emulator: https://www.aliexpress.com/item/FUERAN-HDMI-Pass-Through-EDID-Emulator-for-use-with-video-splitters-Switches-and-Extenders/32814829516.html? (no idea if that particular one is any good) - with those, there's a way to 'train' them where you plug in the display directly and teach it the EDID, which the emulator replays when it's at the far end of the extender and the EDID can't be read. Alternatively just send a fixed resolution like 640x480 without trying to detect what the far end wants. Theo
Thank you guys, especially thanx to  Theo Markettos! in 480P it works.

I want it work on 1080p, could someone help to find it ?
Thank you guys, especially thanx to  Theo Markettos! in 480P it works.

I want it work on 1080p, could someone help to find  VHDL code for DDC  ? 
abirov@gmail.com wrote:
> Thank you guys, especially thanx to Theo Markettos! in 480P it works. > > I want it work on 1080p, could someone help to find it ?
So just try sending 1080p without trying to probe the EDID? If you need timings, 'cvt' is a handy tool to generate standard modes: (you can look up what each column means) $ cvt 1920 1080 # 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync Theo
On Tuesday, September 25, 2018 at 6:18:54 PM UTC+6, Theo Markettos wrote:
> abirov@gmail.com wrote: > > Thank you guys, especially thanx to Theo Markettos! in 480P it works. > > > > I want it work on 1080p, could someone help to find it ? > > So just try sending 1080p without trying to probe the EDID? > > If you need timings, 'cvt' is a handy tool to generate standard modes: > (you can look up what each column means) > > $ cvt 1920 1080 > # 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz > Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120
-hsync +vsync
> >
Cannot transmit 1080p but with 150MHZ, cannot generate 1080p with 173MHZ HDMI