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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

VIP, Interlacer BETA, 480i

QII 9.0 SP2

I have a a clipped image that is 720 x 480p @60Hz, RGB, that I have feeding the Interlacer and then Clocked Video out. My task is to generate "480i". I have the CVO configured as follows:

Interlaced

F0 Sample Count = 720

F0 Line Count = 240

F1 Sample Count = 720

F1 Line Count = 240

HFP = 16

HSync = 62

HBlank = 138

VFP = 2

VSync = 3

VBlank = 19

F0VFP = 3

F0VSync = 3

F0VBlank = 20

APLine = 21

FRising = 264

FFalling = 1

My first question is what should the Pixel Clock frequency be when reading out of CVO? In my past dealings with "480i" I've used 27MHz. When I use 27MHz here my Vsyncs look correct at 16.67ms but I get 525 lines in between the VSyncs and the line rate is 31.6us. If I lower the Pixel Clock to 13.5MHz the Horzontal period looks correct - 63us - but now my vertical period is too wide at 33.3ms.

So it looks like the Interlacer or the interlace function on the CVO is not working. I wanted to at least try to find out if anyone else has done this so I can get the clock correct.

I have not looked at the control packets yet to see what's going on the there - that's next I suppose.

If anyone has any ideas I'd appreciate them - thanks.

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    I have this working now. FYI the pixel clock rate when clocking the data out of the CVO for 480i and 576i is 13.5MHz. The part I was stuck on was getting the CVO registers correct. If they're not just right the output is total garbage.