• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Subscribers 35 subscribers
  • Views 652 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65982: Reading 0x28 register reporting 0x0F as byte count instead of 0x11.

Gary Chambers
Prodigy 130 points

Part Number: TPS65982

We are trying to power off a TPS65982, or as an alternate set it as sink only, to stop powering external devices using register 0x28. When we refer to SLVUAN1A the register 0x28 is meant to return 0x11 bytes, but our device states 0x0F bytes. This may be due to an out of date PDC firmware revision but we currently have no easy method to update our products in field.

Is it possible to get the original document SLVUAN1, details of register 0x28 describing the differences (0x0F instead of the current 0x11).

  • 0
    TI__Genius 16370 points
    Gary,

    Which firmware version are you using?

    Two bytes (16/PP_5V0_OCTimeout and 17/PP_HV_OCTimeout) were added to 0x28 from 1.11.01 onwards - All the other bit-field definitions remain the same. Meaning, if you are using an older version of the firmware, the 15 bytes returned by the device shall be interpreted as Byte1-Byte-15 of 0x28 as defined in www.ti.com/.../slvuan1a.pdf

    Thanks & Regards,
    Praneet
  • 0 in reply to Praneet Kumar
    Prodigy 130 points

    Hi Praneet,

    OK, thanks for clearing that up. Our device is reporting Firmware 1.11.00 (in hex).

    It seems we cannot disable the port with this Firmware revision when writing to 0x28 bits 2:0 of byte 1. Is there anyway we can disable the TPS device with this firmware revision? Or at least set it up in away that it does not provide any external power (i.e. set it as sink only).

    Regards

    Gary

  • 0 in reply to Gary Chambers
    TI__Genius 16370 points
    Gary, Did you write a '7' to Bit:2-0 of 0x28, and it didn't disable the port? That should have worked - Can you do a 'Gaid' after the write to 0x28, and share your observations.

    Thanks & Regards,
    Praneet
  • 0 in reply to Praneet Kumar
    Prodigy 60 points

    Yes, we wrote 7 to those bits. This disables port on the 1.11.5 firmware but not on 1.11.0. Gaid command resets the device on both

  • 0 in reply to ALEXANDER FEINMAN
    TI__Genius 16370 points
    My bad - 'Gaid' would as well re-initializes the register content.

    1.11.0 is a very old firmware version. The changes that are added in the subsequent versions of the firmware to allow updating the configuration registers while in a PD contract cannot unfortunately be back ported to 1.11.0 - While I would recommend an upgrade to the latest patch (v1.12.07), please consider moving to an intermediate version meeting your requirement.

    Thanks & Regards,
    Praneet
  • 0 in reply to Praneet Kumar
    Prodigy 60 points
    Praneet,
    Yes, we know we can do this in newer revisions. The issue at hand was that the units currently in the field do not have the ability to turn off the port and updating the firmware in the field is not supported on these older units. If we update to at least 1.11.5 (or newer), the issue goes away. I was hoping there was some workaround for 1.11.0
  • 0 in reply to ALEXANDER FEINMAN
    TI__Genius 16370 points
    Alexander,

    Unfortunately, there's no workaround. Some fixes might have been added to the later versions of the firmware to solve this problem, but we can't unfortunately back port those fixes - Moreover, that would be a patch change which you wouldn't anyway be able to use 'coz of the limitation of upgrading your units in field.

    Please let me know if I can be of any other help here.

    Thanks & Regards,
    Praneet