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AD9889 video noise on the display

I got the AD9889 HDMI transmitter working, but I see noise on the display. I generate a color bar as a source image, I see a couple of verticle noise striped on some of the colors. If I wiggle the HDMI cable the noise changes.

I started playing with the register settings and first I noticed that the set provided on the web doesn't work. It also does not match the programming guide documentation. One example is register 0x98. The documentation says must write a 7 to this register. The example code says write 178. But I only got a display working by writing a 170. Registet 0xAF also affects the noise on the display. A value of 6 works best, while a value of 4 makes the video break up once in a while. And last but not lease, I had to increase the drive strength registers 0xA2 and 0xA3 to 255 to minimize the noise on the display.

My resolution is 1280x1024, 108MHz clock, 60Hz frame.

Can someone provide me a register settings that work for this resolution that is different than the one available from the web?

I'm attaching the register setting programming that gives me the best results. This is a read back from all registers.

Thanks,
Ed.

best_settings.txt.zip
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  • Yes, the AD9889B. No, I don't have an evaluation board. Could you send me schematics/layout pcb file for the evaluation board. I'm also using a micro-hdmi connector, so the layout had to go through vias from the chip to the connector. Do you think that could be the issue? But there's no other way to connect the chip to the micro connector, only through vias.

    Did you have a chance to take a look at the register setting I attached to the message?

    Thanks,

    Ed.

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  • Yes, the AD9889B. No, I don't have an evaluation board. Could you send me schematics/layout pcb file for the evaluation board. I'm also using a micro-hdmi connector, so the layout had to go through vias from the chip to the connector. Do you think that could be the issue? But there's no other way to connect the chip to the micro connector, only through vias.

    Did you have a chance to take a look at the register setting I attached to the message?

    Thanks,

    Ed.

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