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DS90UB949-Q1: pairing with 948

Bart
Expert 6460 points
Part Number: DS90UB949-Q1
Other Parts Discussed in Thread: DS90UB948-Q1

Team,

we are using the DS90UB949-Q1 and DS90UB948-Q1 ser/des pair to drive some displays in our device.

We are using BIST function on the DS90UB948-Q1 deserializer to check the FPD-Link quality and status during the device operation. After the BIST routine we check the status of the error register (BIST_ERROR_COUNT Register) to check if any errors occurred. However, for additional redundancy, we would also like to check the status of the PASS pin to separately confirm no errors were detected.

The host processor is on the serializer side of things so we need to transfer the PASS pin status via FPD-Link. My question is the following:

Do we need to connect the PASS pin to a separate GPIO and read the corresponding GPIO on the serializer, or can we link the PASS pin to the corresponding GPIO on the deserializer directly if PASS is not configured as GPIO?

Thank you.

 

  • 0
    TI__Mastermind 37370 points

    Hi Bart,

    I don't think it is necessary to connect the pass pin to the GPIO pin. If you are established the linked and locked, then you should be able to read the status of the pass pin via back channel.

    Aaron

  • 0 in reply to Aaron Heng
    TI__Expert 6460 points

    Hi Aaron,

    thanks for the feedback. We are investigating this. 

    Can you provide more detailed information how to read PASS via backchannel? That would help us debug this faster.

    Thanks.

  • 0 in reply to Bart
    TI__Mastermind 37370 points

    Hi Bart,

    The PASS pin can not be read from the serializer side. It is only available for local on the deserializer side. The PASS pin toggle whenever there is an error where CRC error keep track of this. So, if you want, you can access to this via remote register from the serializer side. If you want to monitor the PASS pin from the serializer side, then you configure the serializer and deserializer device via back channel connecting the PASS pin to GPIOx.

    Hope this helps. Let me know if you have further questions.

    Aaron