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ADV7511W : CGMS-A

Question asked by tomoto Employee on Jul 31, 2018
Latest reply on Aug 15, 2018 by tomoto

Hi

I understand ADV7511W HDMI Audio Sample Packets use IEC60958 format which comes from SPDIF or InfoFrame(I2S). PG 4.4.3 Audio Sample Packets

 

Q1) CGMS-A is defined in CEA spec and carried over IEC60958 format.

       In case ADV7511W audio mode was set to SPDIF mode, is the CGMS-A data(2bit) from SPDIF reflected to ADV7511W's HDMI channel status automatically as stated in the PG? 

Q2) ADV7511W I2S mode use resister map for HDMI channel status setting as described in the PG

       Table 62 I2S Channel Status ADV7511W Register Map Location or Fixed Value 

      40 CGMS-A 0
      41 CGMS-A 0

     It looks CGMS-A[40:41] is fixed to 00b, but could you explain the background why we set these bits to 00b?

 

My question above is how to deal with CGMS-A data on HDMI link.

CGMS is for legacy Analog TV copy protection, I'm wondering no need to care?

Please advise if there is a critial usecase of CGMS.

 

Regards,

Tomoto

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