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ADV7612 EVM - Internal E-EDID Option

Question asked by on Nov 20, 2015
Latest reply on Nov 29, 2015 by GuenterL



I have one query regarding the assertion of Hot Plug Detect (HPD) on ADV7612 EVM when internal E-EDID RAM option is used.


I understand that when the HDMI source is connected with the EVM powered OFF, the HPD to the source will be held low (not asserted) by the MOSFET circuit.


When the EVM is powered ON with the HDMI source connected, the ADV7612 will pull HPD low for 1s and then HPD will be asserted (pulled high) by the 1K pull-up resistor to 5V HDMI power signal.


This is because the HPA_AUTO_INT_EDID[1:0] = 01 (default) which implies HPD to the source will be asserted high following programmable delay(default = 1s)  after part detects an HDMI cable plug on that port. 


However at this time, the E-EDID information is not available as the internal RAM is not yet configured. This violates the HDMI specifications which state that "HDMI sink shall not assert high voltage level on the HPD pin when E-EDID is not available for reading".


Please confirm if my analysis is correct. If so, how can the internal E-EDID option of ADV7612 be used without violating the HDMI specifications.