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Original question:

TPS25750: TPS25750 can work without EEPROM? Configuration setting can load by external MCU?

TPS25750: EEPROM loading

Choon Shin
Prodigy 140 points
Part Number: TPS25750

Hello,

I accidently connected EEPROM I2C line pull-ups to the local 3.3V instead of TPS25750 LDO_3.3V.

Q1: After powering on the USB power (V3.3_LDO_PD), when I turn on the local 3.3V (V3.3_LOCAL), I don't see any EEPROM loading in I2C line.

    Could you confirm that this is the expected behavior?

Q2: Is it possible to load the EEPROM by sending commands through the I2C port?

Thanks for your support,

Choon Shin.

  • 0
    TI__Mastermind 24245 points

    Hi Choon,

    Q1.

    Yes, this is expected behavior. It looks like you are loading from dead battery mode(where the PD controller is powered from VBUS, not local 3V3) as we see the LDO3V3 go high before the Local 3V3. The PD will try booting from the EEPROM once after loading, and because the I2C pullups were off, it misses the boot.

    In future versions, we definitely recommend tying the I2C pullup resistors for the EEPROM to LDO3V3.

    Q2.

    I'm assuming here you mean load the PD controller with the configuration from the EEPROM.

    If you are familiar with the 4CC Task Detailed Descriptions (Ch. 3 in the TRM). We have an additional command "Gaid" which does a soft reset of the part and can reboot the flash.

    Thanks and Regards,

    Chris 

  • 0 in reply to Christopher Lim1
    Prodigy 140 points

    Hi Chris,

    Thank you for providing a new command "Gaid".

    I tested it and the EEPROM was successfully loaded but a weird I2C packet (0x6B+RW) was monitored on the EEPROM I2C bus.

    I think 0x6B shouldn't be on the EEPROM bus because EEPROM I2C address is 0x50 and no other device is connected. Could you take a look?

    Also, does it start negotiation with the counter PD controller part? This TPS25750 doesn't change the USB power status even though it's expected to source the power to the counter part. If it doesn't start negotiation automatically, is there any commands to initiate the negotiation?

    Below captures were taken after sending "Gaid" to TPS25750.

    Thank you!

    Choon

  • 0 in reply to Choon Shin
    TI__Mastermind 24245 points

    Hi Choon,

    Let me take a look and I'll get back to you by the end of the week.

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    TI__Mastermind 24245 points

    Hi Choon,

    Typically, the 0x6B I2C address is assigned to a Battery charger part(BQ part) when used with the TPS25750. The From the image of the schematic above, it does not look like you have the battery charger part connected to the pins 16,17 and 18 I2C line.

    If you are using the online GUI, make sure to select a configuration without the BQ(battery charger part). That may be causing the issue with the lack of PD negotiation that you mentioned.

    Thanks and Regards,

    Chris