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DS90UH949-Q1EVM: We cannnot initilize HDMI with local EEPROM

Jose Machado
Prodigy 10 points
Part Number: DS90UH949-Q1EVM

Hello,

We have programmed an EEPROM with all EDID data.

The EEPROM is pluggen in U3. MODE_0 is 5 and MODE_1 is 1.

HDMI is already connected before powe-up the DS90Ux949EVM. After power-up the DS90Ux949EVM , we can see the image correctly for abaut 1 second and then image the image disapear.

If we power-up the DS90Ux949EVM and after that we connect the HDMI we do not see any image.

In both cases, if we press the S4 PDB then we can seen the image and it is stable and does not disapear.

What can we do to initialize correctly the image with the EDID from the local EEPROM? Can we send a I2C command?

Many thanks, Jose

  • 0
    TI__Mastermind 29605 points

    Hi Jose

    Thanks for the details! Please see my input below.

    You mention that your mode_0 is 5 ? This 949 device has only 4 setting options for mode_sel0 - Can you please clarify ?

    As far as setting up an external Local EDID - Please note:

    1. For external local EDID, you must set EDID_SEL = 1
    2. The communication of the EDID will occur directly between the HDMI source and the EEPROM on the DDC bus for that mode.
    3. The 949 is not involved in the EDID transaction at all for that configuration.
    4. You must place an EEPROM on the DDC bus socket on the EVM and you must have flashed the EDID into the EEPROM already.
    5. Also the EEPROM device must have the 8 bit I2C address of 0xA0 so that the HDMI source will recognize it. 
    6. Also note that for the HDMI exchange to start, HPD must be high from the 949. For HPD to be high, the 949 must detect a downstream DES connection so you need to have the 949 EVM connected to a DES EVM with a proper link. 
    7. Lastly, since you mention that PDB reset fixes the issue, this could be a EDID mode issue since PDB resets all the registers to default, it could indicate that your initialization script could be causing this behavior

     

    Lastly, it's always recommended to double check section 9.1 (Power-Up Requirements and PDB Pin) in the datasheet to ensure the power-supply ramp and PDB delay timing requirements are met per datasheet recommendations.

    Regards,

    Fadi A.