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TPS65987EVM: 10G-EXPANSION-EVM no DP video

Laurence Symonds
Intellectual 545 points
Part Number: TPS65987EVM
Other Parts Discussed in Thread: TPS65987

Hi

I am having an issue with my TPS65987EVM with 10G-EXPANSION-EVM sink board. I have previously had this setup working so I'm not sure what has changed but now when I try and output DP video from my laptop, nothing happens.

I think it is related to the HPD but am a little confused. On the hardware everything seems fine. The HPD LED is on and the monitor is switched on. However when I look at the debug registers, it shows the DP HPD is low and the PD log seems to exit alt-mode after transmitting that the HPD is low.

I have check continuity between the LED transistor gate and the HPD pin on the TPS65987 in case the Samtec connector had been damaged, but that is fine. Would this be a setting issue or is it a hardware issue?

Thanks

  • 0
    TI__Genius 12700 points

    Hi Laurence, 

    Do you remember configuring any changes to the settings after you had this setup working? If not, it may be hardware related or they may have been some external damage. Could you send you project configuration file and the log file as well so that I can see the individual messages in detail to see if there's any problems in the process? The HPD bit will go high after the PD controller receives a IRQ_HPD attention message which may not have happened causing the low HPD signal so I would need to verify this in the PD logs.

    Thank you,

    Hari

  • 0 in reply to Hari Patel1
    Intellectual 545 points

    Hi Hari

    Thanks for the reply.

    No I don't think I have changed settings from when it worked OK. I have attached pjt file and the analyser log. I am using a Cypress CY4500 device and EZ-PD software. You might need this software to view the log.

    As a test, in the IO config, I tried mapping GPIO3 (HPD) as a mapped cable orientation event, the same as GPIO1 which is connected to the flip LED. With no DP cable attached, in theory this should light the HPD LED on the 10G-EXPANSION-EVM when the USBC cable is in reverse orientation, similar to the flip LED, but nothing happened. I probed the voltage at the pin on the IC and it was 0V.

    So my suspicion is that it is hardware related, but apart from this pin I haven't noticed any other perculiarities from the IC. This seems like a strange thing to happen to the hardware.

    Is there a way to negotiated a DP connection without the HPD pin? As in use software to override the actual state of the pin?

    Many thanks

    USB PD log and pjt.zip