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DS90UB928Q-Q1: can DS90UB928Q-Q1 generate "VDD_EN" and "BKLT_EN" for LCD panel by itself? thx!

Part Number: DS90UB928Q-Q1

Hi Madam/Sir,

Fig.1 is our current display diagram. it consists of Intel SoC,  DS90UB929, DS90UB928 and LCD panel.

we met LCD panel sequence problem since there is no VDD_EN and BKLT_EN from HDMI and we cannot pass it to LCD panel thru GPIO of DS90UB929/928.

Fig.1

we wounded if there is any way to extract "VDD_EN" and "BKLT_EN" from HDMI and pass it to LCD panel thru GPIO of DS90UB929/928? like to Fig.2 or others.

please kindly share us your thought or comment. Thanks a lot.

Fig.2

Regards,

Eric Li

  • Hi Eric,

    How are the control signals being sent over HDMI? Is it using the DDC?

    Can the SoC not send the VDD_EN and BKLT_EN signals over its GPO pins? This would let us send the signals over the 929 GPIO. 

    Regards,

    Jack

  • Hi Jack,

    Thanks for your support.

    the SoC does not have VDD_EN and BKLT_EN signals for its HDMI interface.

    is there any way to split extract "VDD_EN" and "BKLT_EN" from HDMI, DDC or DATA?

    if there is, we can send the signals over 929 GPIO.

    Regards,

    Eric Li

  • Hi Eric,

    On the 929, only the audio can be extracted from the HDMI signal. The DDC channel is only used for reading the EDID. I will consult the team on whether the CEC can be used for extracting control information to the GPIO.

    the SoC does not have VDD_EN and BKLT_EN signals for its HDMI interface.

    So can the SoC not send out these signals on the non-HDMI interface pins? Have you already contacted the SoC vendor to see if they can route these signals onto non-HDMI pins?

    Regards,

    Jack

  • Hi Eric,

    The HDMI interface on the UB929 cannot extract control information from the HDMI input. My recommendation for the VDD_EN and BKLT_EN signals is to either use the GPIO interface on the UB929 or the I2C bus on the 929 to send over these signals.

    Regards,

    Jack