Keep EDID data ADV748X only with 5V via HDMI connector

Dear Sir/Madam,

Can I keep ADV748X EDID data in EDID RAM if system only provides 5V power via HDMI connector, and the other power are all power down? 

If I can't keep those data with HDMI 5V, how would you suggest me to do in order to pass HDMI certification item (Test ID 8-1) which requires that EDID can be read after powering down for general case.

Thanks very much!

Henry

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  • Hi,

    The data in the EDID will not be maintained in the EDID RAM if the supplies to the ADV748x are not provided. Please see Section 5.3.1.4 in the Hardware Manual:

    The E-EDID/repeater controller is reset when the DVDD supplies go low or when hdcp_rept_edid_reset is set high. When the E-EDID/repeater controller reboots, it performs the following tasks:

    • Clears the internal E-EDID and Key Selection Vector (KSV) RAM (refer to Section 5.3.8.2)
    • Computes a checksum

    Test ID 8-1 in the CTS spec states that after powering down the Sink DUT and still applying the 5V signal on the HDMI connector, the EDID should be read if the sink asserts HPD. The ADV748x will not assert HPD if the supplies are not provided to it. So the EDID will not be read when the Sink is powered off.

    Best Regards,

    Jeyasudha.M

Reply
  • Hi,

    The data in the EDID will not be maintained in the EDID RAM if the supplies to the ADV748x are not provided. Please see Section 5.3.1.4 in the Hardware Manual:

    The E-EDID/repeater controller is reset when the DVDD supplies go low or when hdcp_rept_edid_reset is set high. When the E-EDID/repeater controller reboots, it performs the following tasks:

    • Clears the internal E-EDID and Key Selection Vector (KSV) RAM (refer to Section 5.3.8.2)
    • Computes a checksum

    Test ID 8-1 in the CTS spec states that after powering down the Sink DUT and still applying the 5V signal on the HDMI connector, the EDID should be read if the sink asserts HPD. The ADV748x will not assert HPD if the supplies are not provided to it. So the EDID will not be read when the Sink is powered off.

    Best Regards,

    Jeyasudha.M

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