Showing results for 
Search instead for 
Did you mean: 
Honored Contributor I

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: 



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.
0 Kudos
1 Reply
Honored Contributor I

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.