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AD9889B and 1080p60 problem

Hello,

I am using an AD9889B,sucessfully transmitting 720p60 and 480p60 signals.

Now I tried to transmit 1080p60.

AD9889B corrently recognizes the mode that I send to it by reading these registers(R0x3D=0x10,R0x41=0xF8,R0x42=0x10,all circuits powered up and Hot plug active),but the display is black.I've tried many diffrent displays(samsung and others),all displays are black.

I modify R0xA2 and R0xA3 to 0X87,and change the timing sequence following EIA-CEA-861-D(verified with a scope),and using videoclock of 148.5MHz,but it's not working.

I've tried 1280*768 60Hz too,the videoclock of 108MHz,the display is sign good and black from time to time.

I am not using HDCP.

Any other regiter must be modfied?

many thanks

Tom

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  • Hi Tom,

    You will find scripts for many modes on the Design Support Files page of ADV7441A-- ver 2.0 scripts use the AD9889B as the HDMI TX.  The bottom part of each script are the settings for AD9889B for each particular configuration.

    If your VCLK is out of specification, it won't matter if your power supply is noisy or not.  It still won't work. The maxumum allowed power supply noise is 50mv peak to peak-- it's in the data sheet.

    Dave

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  • Hi Tom,

    You will find scripts for many modes on the Design Support Files page of ADV7441A-- ver 2.0 scripts use the AD9889B as the HDMI TX.  The bottom part of each script are the settings for AD9889B for each particular configuration.

    If your VCLK is out of specification, it won't matter if your power supply is noisy or not.  It still won't work. The maxumum allowed power supply noise is 50mv peak to peak-- it's in the data sheet.

    Dave

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