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DS90UB947-Q1: GPIO1 can not be controlled

Rocky Chen
Expert 8810 points
Part Number: DS90UB947-Q1

Hello,

During prototype debug, it was found GPIO1 of 947 can not be configured. The pin was always locked at logic low.

We set 0x0e with value 0x33, to set both GPIO1 and GPIO2 as input, and then pass through to 948 side as output. GPIO2 channel succeed, and GPIO1 failed.

We read back 0x1c of 947, its value is 0x04, which shows GPIO2 is configured as input as we expected, but GPIO1 not. 

What happens on GPIO1 of 947? What is the reason that make it can not be configured as input?

Thanks!

  • 0
    TI__Genius 10475 points
    Hello, this has been assigned for the local Apps person to take a look at and respond to.
  • 0 in reply to Palaniappan Manickam
    TI__Mastermind 30515 points
    Rocky,
    the register 0x0c indicates the GPI pin status, it means the input at GPIO1 pin is low in your case.
    To make UB947/948 remote GPIO work correctly, please refer to page19 in d/s. In your case, as UB947's GPIO is enabled with forward channel, you should secure UB948's register 0x1E[3:0] must be configured as 0'b 0011. thanks.

    best regards,
    Steven
  • 0 in reply to Steven(Shenzhen) Shi
    TI__Expert 8810 points

    Hi Steven,

    Yes, as I said, we configured GPIO1 and GPIO2 both as forward channel, but only GPIO2 works, GPIO1 failed. The phenomenon is GPIO1 of 947 out of control, with logic 0 locked. We verified the SOC's output to GPIO1 of 947 is logic 1, but the GPIO1 pin seems internally locked to 0.

    The commend we used is just followed page 19 of 947, 0x0E of 947 is 0x33, 0x1E of 948 is 0x55. It does not make sense why GPIO2 works and GPIO1 does not.

    Is there any other configuration we missed? We noticed GPIO1 of 948 is functional shared with SWC, we tried some tuning in 948 side, but no effect. 

    Can you please help think see any other clues?

    Thanks!

    Rocky

     

  • 0 in reply to Rocky Chen
    TI__Mastermind 30515 points
    Rocky,
    it does not matter with the shared pin "SWC". Have you met this issue in all boards? can you share the sch., and dump all registers to check?

    best regards,
    Steven
  • 0 in reply to Steven(Shenzhen) Shi
    TI__Expert 8810 points
    Hi Steven,


    Finally, we found this issue is related with Mode Sel0/1 settings. With 5 of ModeSel0, 2 of ModeSel1, this issue can be reproduced in 947 EVM. After change ModeSel1 to 1, then issue disappeared in both EVM and prototype, GPIO1 can be configured.

    However, looks the #1 and #2 of ModeSel1 are same impact, they both set MAPSEL and COAX with 0. So we wonder to know how to explain this well? Can you please verify this?



    Thanks!

    Rocky
  • 0 in reply to Rocky Chen
    TI__Mastermind 30515 points
    Rocky,
    the modesel1 setting is verified as your lab test, you can set the modesel1 to 1 for correct operation.
    but please be noted that: in setting in modesel1 to 2, the register 0x1c is correct when GPIO1 of UB947 is set at high voltage.

    best regards,
    Steven