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HDMI receiver(ADV7441A) outputs black pixels during active video period

Question asked by ashwa116 on Oct 13, 2011
Latest reply on Oct 13, 2011 by DaveD

Hello,

 

We are using HDMI Tx(AD9889B) and HDMI Rx(ADV7441A) in our setup.

 

Setup:
In one board(BOARD1) FPGA drives digital RGB, VSYNC, HSYNC, DE, and PCLK to HDMI Tx.
In the other board(BOARD2) the HDMI Rx digitizes data from HDMI channel and outputs digital RGB, VSYNC, HSYNC, DE, and PCLK to FPGA.
The BOARD1 HDMI Tx output is loopbacked to BOARD2 HDMI Rx input.
  We have done HDMI Tx configuration as per attached file(HDMI_Tx_configuration.c) for 1280X720@50fps, and HDMI Rx configuration as per attached file(HDMI_Rx_configuration.c) for 1280X720@50fps.
  We are sending the fixed image from BOARD1 FPGA with timing as per EIA/CEA-861-B.
(VSYNCFP= 9,VSYNCPW= 6, VSYNCBP= 30, HSYNCFP= 440,HSYNCPW= 62, HSYNCBP= 60)

 

Issue:
The expected frame is received in the BOARD2 FPGA. For every ~10secs the display goes black for one or two frame (Flashing effect).
The black pixels are captured by BOARD2 FPGA from HDMI Rx.


The Flashing effect is not seen if the frame is single color(For example Complete RED frame).

And also, the flashing effect is not seen for 720X480@60fps with fixed frame.

 

Note that if we connect the output of BOARD1 HDMI Tx to HD monitor the display is perfectly fine.

 

Please help us to resolve the issue.

 

Thanks and Regards,
Ashwath

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