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BT.656 -> ADV7390/1 -> VGA?

Question asked by bytejammer on May 24, 2012
Latest reply on Jun 22, 2012 by tommyo

Can the ADV7390/1 output progressive analog VGA (640 x 480) from an 8-bit BT.656 input?

 

The VGA timing standard I'd like to use can be found here.

 

From reading the ADV7390 datasheet, it seems the closest setup script to achieve VGA output  is provided in Table 109. 8-Bit 525p YCrCb In (EAV/SAV), RGB Out. Using that data as a basis, I think the following settings may work:

 

Register 0x01:

Select ED/HD-DDR input with a CLKIN frequency of 25.175MHz (VGA pixel clock) -OR- perhaps ED input mode with input clock = 50.35MHz (25.175MHz x 2).

 

Register 0x02:

No sync on RGB, select RGB component outputs, output ED/HD syncs on HSYNC# and VSYNC# pins (sync signals are required at VGA receiver).

 

Register 0x30:

Use embedded EAV/SAV codes for ED/HD input sync format, select 525p at 59.94Hz

 

Register 0x33: 8-bit ED/HD input format

 

Using these settings I believe I could achieve the VGA output horizontal timing by controlling where/when the EAV/SAV codes are inserted in the BT.656 input stream. Is there any reason why this wouldn't work with ADV7390?

 

Thanks.

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