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Visitor bretmmyers
Registered: ‎03-05-2012

Atlys: Problems using HDMI Type-D port JA as Input

Hey all,


Summery: On Atlys, HDMI Data Transfer JA → J3 has green and blue syncing up but not red. Why?


I'm working on a grad school project involving, among other things, high bandwidth data transfer from Atlys board to Atlys board over the HDMI ports. I've run, read and studied XAPP495, along with relevant parts of XAPP460, XAPP1064, UG381, UG382 and a host of forum posts and websites. The HDMI source is mostly modules from XAPP460 and XAPP495.


I'm really stuck and need help. I'm trying to use JA as an input with a signal sent from J2. JA's RX_DE is never going high. The clock is being acquired, as I can see from the pclk running. RX_Red, RX_Green and RX_Blue are all using different instantiations of the same module. RX_Green and RX_Blue are receiving the correct control codes and data (examined in both 8b and 10b, sampled immediately after the toggle after the serdes that assigns rawword to rawdata). RX_Red seems to be receiving junk (no data or control codes) and the junk is not random (the same words repeat). It is not an inverse of the data that is being received from green or blue. I do have 50 ohm resistors functioning as pull ups to Vcc. I have tested the same .bit's on multiple boards and can replicate the problem (and patterns received).


I don't think that the bits could be shifted unless it were shifted by +6 bits. For example, the top 8 bits of 10B on red may read 0111 1111, while green and blue would both read 0000 0001. I can find more and less extreme examples.


The code works fine when I run (Output → Input) J2 → J1, J2 → J3, JA → J1, JA → J3. I'm out of ideas. Any suggestions? Has anyone else had success in using the JA port as an input?


Thank you.

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Scholar joelby
Registered: ‎10-05-2010

Re: Atlys: Problems using HDMI Type-D port JA as Input

I'm afraid I haven't tried to do anything like this. Does the XAPP495 dvi_demo video switcher design allow you to successfully transfer video from JA to J3, though?

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