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ADV7842 configuration when there is no HDMI 5V signal.

Question asked by raymondcarter Employee on Nov 20, 2013

Hi All,

 

Our recommendation is to always have 5V connected to RXA_5V/RXB_5V of the ADV7842.

 

In the event where there is no 5V connected or sources which do not supply 5V the following can be carried out to process the signal.

 

The customer needs to ensure that the system provides a Hot Plug high level back to the connected device.

The ADV7842 cannot  drive back the HP signal. ( HP pin on ADV7842 is open drain design.)

 

The following I2C writes should be carried out.

HDMI Map Register 0x48-> 0x40  Disable cable detect reset.

HDMI Map Register 0x69-> 0xA3  Manual Hot Plug Control

HDMI Map Register 0x45-> 0x00  Enabling clocking when 5V detect signal.

 

 

Rgds,

Ray

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