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Sync signal of VIP Clocked Video Input

Altera_Forum
Honored Contributor II
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Hey guys, 

 

Just one quick question about the sync signals of Clocked Video Input megacore: 

 

The manual said vid_h_sync should be set to 1 when video is in horizontal synchronization period. But what is the horizontal synchronization period here? Is it Front porch, Back porch, Sync pulse or Active Sample? Thanks very much!
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Altera_Forum
Honored Contributor II
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vid_h_sync is only referring to the horizontal synchronization period and not the blanking period. 

 

If you read the section on Separate Synchronization Format it hints that vid_h_sync is strictly the horizontal synchronization period, and does not include the blanking periods. This can be seen further through the timing diagram, where the h_sync pulse is asserted between the two vid_datavalid sections. The vid_datavalid indicating active picture period. 

 

The documentation could be more explicit on this.
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Altera_Forum
Honored Contributor II
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Thanks for your reply. I have just gone over the manual. Just to double confirm: 

the horizontal data flow is: H front porch -> H Sync -> H back porch -> pixel data, and then repeat itself. 

 

h_sync is asserted during "H Sync" only; and vid_datavalid is asserted during "pixel data" only. Is that correct?  

 

Thanks very much! 

 

 

 

 

--- Quote Start ---  

vid_h_sync is only referring to the horizontal synchronization period and not the blanking period.
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Altera_Forum
Honored Contributor II
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That is correct. The h_sync signal is not asserted during the front porch or back porch periods of the horizontal blanking period, and the vid_datavalid is asserted during the active picture time.

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Altera_Forum
Honored Contributor II
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Did you get this running? I am running into a issue trying to create a test pattern into the Clocked Video Input. The clocked video input is set to 800x600. What is the front porch and back porch settings and sync timing you used? 

 

Thanks
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Altera_Forum
Honored Contributor II
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I was using 640x480, and I got it working. 

The timing info I used comes from the link below:  

http://tinyvga.com/vga-timing 

 

The key is that either "Sync pulse" or "Sync pulse + Front porch + Back porch" should be set as blank period. Sorry I forgot which setting I was using. But you should be able to figure it out after trying both. :o
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