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[ADV7390] The input digital data during blanking area is inserted to the CVBS output.

Question asked by Tamu on Sep 30, 2015
Latest reply on Nov 12, 2015 by Tamu

Hello,

 

I have some questions about ADV7390.

 

Question 1:
When "SD CGMS on even/odd fields" (0x99[6:5]) is "11" (enable) and "SD VBI data" (0x83[4]) = 0 (disable), the CGMS data inserts to the analog output CVBS from ADV7390.
(The datasheet on page 52 says "If CGMS is enabled and VBI is disabled, the CGMS data is, nevertheless, available at the output.".)
The CGMS data are set to "SD CGMS" registers (0x9A and 0x9B), so I think digital input during blanking area is not inserted the analog output CVBS.
Is this true?
Or do digital inputs during blanking area affect the analog output without depending on the settings of registers 0x99[6:5] and 0x83[4]?

 

Question 2:
When "SD CGMS on even/odd fields" (0x99[6:5]) is "11" (enable) and "SD VBI data" (0x83[4]) = 0 (disable), dark green image can be seen during blanking area on the customer's board.
When "SD CGMS on even/odd fields" (0x99[6:5]) is "00" (disable) and "SD VBI data" (0x83[4]) = 0 (disable), dark green image can also be seen during blanking area.
Please refer attached file "150930_V7390_Wrong_VBI_output_rev02.pptx".
The input digital data YCbCr is all 0 (= dark green image) during blanking area, so we think it can be inserted to the CVBS output.

Does ADV7390 have any register for not outputting digital data during blanking?
Do we have to set black image (Y=0x10, CbCr=0x80) during blanking?

 

Thank you!
Best regards.

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