Post Go back to editing

ADV7613 Internal EDID RAM & Program

Category: Hardware
Product Number: ADV7613

Hello

1. What's the internal ram size? (DS does not mention it.)

2. I want to program EDID. Can it program in internal EDID RAM directly? Or, it always needs outside EEPROM?  

   If it can be programed in internal EDID RAM, connect program tool with DDC_SDA& DDC_SCL. Does it need pull low other pin?



updated with New ask a question form
[edited by: GenevaCooper at 1:49 PM (GMT -4) on 23 Sep 2022]
  • Hi,

      Please find the below comments,

    1. What's the internal ram size? (DS does not mention it.)

                Internal E-EDID memory of legacy HDMI part can store 256 bytes (i.e RAM SIZE: Internal E-EDID memory can store only upto 256 bytes) .

    Generally, a legacy HDMI system will have only two EDID blocks(256 bytes) and will only use segment 0. The first EDID block is always a base EDID structure defined in VESA EDID specifications and the second EDID block is usually the CEA extension defined in the CEA-861D specification So in general, HDMI devices expect both blocks (all 256 bytes) to be populated.

     2. I want to program EDID. Can it program in internal EDID RAM directly? Or, it always needs outside EEPROM ?  

            Please note you can use either internal EDID or External EDID at a time and its not possible to use both Internal & External EDID. So if the internal E-EDID RAM is enabled for one specific port and an external E-EDID storage device must not be connected on the DDC bus of that port.

    If it can be programed in internal EDID RAM, connect program tool with DDC_SDA& DDC_SCL. Does it need pull low other pin?

       In order to program the internal memory, the external master device should connected to the system's I2C bus.(i.e External processor/controller's/Aardvark I2C lines should connected to Internal EDID Memory) .

       So we can program the Internal/External memory via the Blackfin or if you have a I2C interface like Aardvark you can program the memory directly.

       As Per the HDMI spec, the HDMI Source/Transmitter knows to read the sink/receiver's E-EDID after it detects that HPD is high.

    Note: DDC or Display Data Channel describes the protocol and physical path used by the source and display to communicate. It is typically assigned to a pin or pins on the interface, and carries the EDID/HDCP.

    Source should use the DDC to read the EDID data from Sink devices. If incase the DDC lines are not connected then source can send any specific format without knowing the Sink capability (i.e DDC signals are not connected to the HDMI receive connector, it means that the source device will not be able to read your board's EDID).

    Please refer this FAQ for more information about EDID and its terminologies,

      EDID: Extended Display Identification Data - Documents - Video - EngineerZone (analog.com)

    Thanks,

    Poornima