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DS90UB947-Q1: Enable GPIO outputs on deserializer on link detection

Brent Sink
Prodigy 20 points
Part Number: DS90UB947-Q1
Other Parts Discussed in Thread: DS90UB948-Q1

Tool/software:

Hello,

I have a custom board using the DS90UB947-Q1 serializer which is connected to the DS90UB948-Q1 deserializer.  My OS is Linux, and I can set the outputs on the deserializer by using the registers.  However, upon power loss of the deserializer, the register values are lost and when the deserializer is powered again and a link is established, the outputs remain off because the register settings are no longer there.

Is there a way for the serializer to set the outputs on the deserializer so that when the link is established the outputs automatically get set?  Or do I just need to constantly monitor the link status of the serializer and be prepared to set the deserializer registers whenever it comes online?  For these particular deserializer outputs I do not have physical inputs on the serializer to drive them from the MCU, thus I must rely on setting the outputs from the registers.

EDIT: I see that GPIO_0, GPIO_1, GPIO_2, and GPIO_3 all have a "Remove Enable" bit to "Enable GPIO control from remote Serializer.".  It looks like this bit is not applicable to GPIO_4 - 8.  Do I need to use GPIO_0 - 3 if I want the output to be set automatically?

Thank you!

  • 0
    TI__Mastermind 33415 points

    Hi Brent,

    Once the deserializer loses power, any register settings will be lost since the registers are volatile memory. The system controller will need to monitor for loss of lock and reprogram the appropriate 948 registers once the link is restored.

    Only GPIO0-3 and D_GPIO0-3 are capable of sending signals from one side of the link to the other. The remote GPIO control option enables the GPIO on the 948 to forward signals it receives on the 947 GPIO input.

    Best,

    Jack