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ADV212 with 576p @ 25Hz

Question asked by James.H on Oct 7, 2014
Latest reply on Oct 10, 2014 by James.H

Hello,

 

We're trying to use the ADV212 in encode mode using VDATA[11:4] and JDATA bus. Our PLD is de-interlacing BT.656 video and passing frames of video (576p, YUV 4:2:2, 8-bits per sample) with embedded syncs to the ADV212 at 25Hz (27MHz VCLK).

 

We have previously managed to get the device working in Raw Video Mode and outputting data on JDATA, but unfortunately the output was not suitable to our application and so we have switched from Raw Video Mode to inserting EAV/SAV embedded syncs instead. However, we are currently unable to get any output on JDATA.

 

SCOM[3:0] goes through the usual start-up cycle of 1-7 and then halts on 7, so we believe the device firmware is being loaded correctly and that it is either a) Not accepting the video format we're sending in to it, or b) Our register settings have incorrectly setup the device for the expected video. However, we are currently unable to probe SCOM[3:0] directly and are instead using reads of indirect register 0xFFFF1404, therefore there is a possibility that we have missed an initial cycle of compression before the device gets stuck at 7.

 

To the best of our knowledge the video is correctly presented and clocked into the device, and our register settings seem sensible, so we wondered if anyone could offer any advice on gotchas when using this mode, and to see if any of our register values appear incorrect. For example - does this mode require both embedded syncs and discrete syncs to work correctly? Is 25Hz progressive  acceptable to the device or does it make assumptions on frame rate?

 

For the indirect registers we read out the reset values and check them against those presented in the User Guide, before writing our own values and then reading them back to confirm that they match, so we have reasonable confidence that the register values are being written correctly.

 

I have attached our register settings along with our defined input video dimensions.

 

Many thanks for any help you can offer.

 

Regards,

 

James

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