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AD725 issues

Question asked by HankZ on Aug 26, 2013
Latest reply on Sep 6, 2013 by DaveD

We have an ongoing project which is using ivy bridge + QM77 platform + AD725. The system equipped with on TVOUT(NTSC) by extract analog signal from standard VGA output. Following picture is the result of display.



Unfortunately, I checked the datasheet as following description. It look like “noninterlaced” and “interlaced” mode is the first problem to me. How do I check and modify the “internal register” to make it work? Do you have any similar application or customer that are using the same platform?


Displaying VGA Output on a TV


The AD725 can be used to convert the analog RGB output from a personal computer’s VGA card to the NTSC or PAL television standards. To accomplish this it is important to understand that the AD725 requires interlaced RGB video and clock rates that are consistent with those required by the television standards.


In most computers the default output is a noninterlaced RGB signal at a frame rate higher than used by either NTSC or PAL. Most VGA controllers support a wide variety of output modes that are controlled by altering the contents of internal Registers  It is best to consult with the VGA controller manufacturer to determine the exact configuration required to provide an interlaced output at 60 Hz (50 Hz for PAL)


I saw there is a tool to make the resolution and display mode fit in the standard of NTSC from your website. Do you have any kind of the tools that can help me to test the functionality of AD725.