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DS90UH925Q-Q1: Enabling INTB: Is there a way to configure register C6 from a remote deserializer via the BCC?

Part Number: DS90UH925Q-Q1

I have an application that requires 24 bit color.  I would like to use the INTB pin as a control output on the 925 to reflect the input on the 926 INTB_IN.  The datasheet shows this is a normal function, however attempts to write register C6 via the 926 deserializer using the BCC appear to not set any bits in the register.  All registers above 0xA0 appear return 0x00 when read including the HDCP TX ID (FX) register set.  Are these registers restricted to local access only?    I can read and write the configuration registers in the 0x0X range and communicate with the External Video interface via I2C so this isn't a basic question of the BCC functioning.

Please note that parts I am testing with are from a design released in 2015. 

  • Hi Craig,

    Could you please confirm if you have the link established between serializer and deserializer? I will also check on my side as well.

    Aaron

  • Yes the link establishes and I can configure both the 925 & 926 to enable video and Audio through an I2C  master on the 926.  The issue appears to be that TI placed the INTB interrupt pin configuration register in the HDCP register address range (since it contains interrupts for HDCP as well).  From another E2E post TI commented that the HDCP registers in the 925 are not accessible from the 926.  This is a shame as I just needed one GPO to allow triggering a master reset on a watchdog IC that would in turn provide a timed reset to the remote video interface and also clear the 925 INTB pin back to Hi-Z.  I believe the only solution will be to use a single GPIO of an 8 bit I2C port expander.

    Please confirm there is no way to configure the INTB pin to follow INTB_IN using a register outside of the HDCP address space.

  • Hi Craig,

    The INTB registers can be only accessed locally.

    Aaron