ADV7511 Output issue

Hi,

 Please configure according to the reference script at initially, which is available at https://ez.analog.com/video/w/documents/797/advantiv-eval-adv7612-7511-video-evaluation-board

 And also refer design support files here https://ez.analog.com/video/w/documents/794/adv7511-design-support-files

Thanks,

Poornima

Dear  Poornma,

           We work together use our EVAL-adv7612-7511 do test use one same cable, the phenomenon still exist, and we reffered the demo kie setting the problem has not change. Is there  any other suggestion about this case? Thanks a lot.

Hi,

Please crosscheck the following steps,
 1) change the drive strength on the FPGA outputs.
 2) Remove the parallel termination at the 7511
 3) Can you tweak the phase of the LLC clock in relation to the pixel bus.
The adv7612 has the ability to phase adjust the pixel clock in relation to the pixel bus data.  We had to adjust this to make it work correctly on the reference board.
 4) Also check the LLC trace length versus the data lengths

Please refer https://ez.analog.com/video/f/q-a/8818/adv7511-llc-issue-at-higher-frequencies

Thanks,

Poornima

Dear Poornima,

        And we work with customer do test as your advice, there's no change in terminal sitution. so we try to use another way  to change R_EXT resistor from 887(recommend value ) ohm to 879.9 ohm (parallel 100K ohm) , if we use our finger to touch the resistor the noise point disappear. And if we parallel a capacitor with external resistor(pin28) and use finger to touch it the phenomenon changed.  There's a question that did we can change this R_EXT ? if it does, how to change this value of this external resistor.

      We also tried to use external  PI3HDX412BD（HDMI1.4b 1 to 2Splitter）,and pull up it internal resistor. The probelem has been solved.Does it mean that our 7511's output capability has been enhanced ? 

Hi,
Current Reference Pin: R_EXT
The external reference resistor should be connected between the R_EXT pin and ground with as short a trace as possible.
The external reference resistor must have a value of 887 Ohms (+/-1% tolerance).
It is strongly recommended to avoid running any high-speed AC or noisy signals next to the R_EXT line or close to it.
Specifically it is recommended that no switching signals – such as LRCLK (including vias) be routed close to R_EXT pin (14).
Low-level TMDS switching noise should have minimal impact on R_EXT. Therefore, it is acceptable to place a via for R_EXT near TMDS signals such as TX0+ and TX0-
Please refer ez.analog.com/.../adv7511w-r_ext-value

Thanks,

Poornima