TFP401: TFP401 have additional 1 error line in the start of a frame

Jason Shen

Intellectual 1965 points

Part Number: TFP401

Dears

We have a case is use the HDMI to RGB convertor, the resolution is 1280 * 800, and input is using the AC coupling. Currently we have an error line and we have done two test.

1. with a dark screen, there have a noise line in the screen left.

2. with a image, there have a noise line in the screen left, and the image have 1 line shift to right.

So seemed the TFP401 have add one line for the display, and is there some solution in this case?

Thanks

Jun Shen

over 3 years ago

0 Brian Zhou over 3 years ago

TI__Guru*** 146195 points

Jun:

Can you send schematic for review?

Regards

brian

0 Brian Zhou over 3 years ago in reply to Brian Zhou

TI__Guru*** 146195 points

0 David (ASIC) Liu over 3 years ago in reply to Brian Zhou

TI__Guru**** 177396 points

Hi,

The TFP401 is designed to work with a DC-coupled input, why are you designing a AC-coupled input?

Thanks

David

0 Jason Shen over 3 years ago in reply to David (ASIC) Liu

TI__Intellectual 1965 points

Hi David

Thanks for the help, and before customer have some use case used the AC coupling. currently have find the root cause of the DE signal, the DE signal have 2 cycle ahead than normal. if customer delay the DE signal of 2 CLK cycle, the error line will be removed.

The DE signal is generated by our chip, so customer want to know how our device generate the DE signal? and which parameter will have impact on when the DE signal active?

Thanks

Jun Shen

0 David (ASIC) Liu over 3 years ago in reply to Jason Shen

TI__Guru**** 177396 points

Jun

The TFP401A discriminates between valid pixel TMDS characters and control TMDS characters to determine the state of active display versus blanking, i.e., the state of DE.

Thanks

David

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TFP401: TFP401 have additional 1 error line in the start of a frame