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Original question:

HD3SS3220: MODE can't be change by MODE_SELECT in attached state

HD3SS3220: Changing MODE_SELECT with a PORT Resistor Connected to GND

Marc Ledesma
Prodigy 20 points
Part Number: HD3SS3220

Tool/software:

Hi Team,

We have several devices that we no longer have access to, but we want to modify their configuration mode.

Currently, the device has a 4K7 resistor connecting the PORT pin to GND, meaning it operates as UFP (Device only). The question is whether modifying the 2 MODE_SELECT bits in the General Control Register would allow configuring the device as DRP (Dual Role), and if so, whether any prior registers need to be configured.

Regards,


Marc Ledesma

  • 0
    TI__Mastermind 26310 points

    Hi Marc,

    The MODE_SELECT pins can be changed, so long as the device is not in the ATTACHED state, and that the ADDR pin is set to I2C mode. If it is in an attached state, or if the ADDR pin is not set to I2C mode, then it can not be changed.

    Otherwise, I don't believe any registers have to be written to prior to this. You could disable UFP accessory support, but I don't think its a requirement:

    Please let me know if you have any other questions.

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Prodigy 20 points

    Hi Ryan,

    First of all, thank you for your response. The question arises because, in my opinion, the datasheet is somewhat ambiguous about when and how the configuration modes can be set. Let me explain:

    In section 7.3.1, it is stated that the DFP mode can only be configured through registers when the PORT pin is floating, which seems to imply that if we have a resistor installed, we cannot configure this mode.

    In section 7.3.2, there is no mention that the PORT must be floating. Therefore, we understand that regardless of whether a resistor is present or not, we should be able to configure the device in this mode.

    In section 7.3.3, it is stated that the device can be configured in DRP mode "when" the pin is floating, which seems to suggest that this mode can only be set when the pin is floating.

    I would also like to confirm whether, in the first sentences of sections 7.3.1 and 7.3.2, when it says "DFP only" and "UFP only," it refers to the DFP-only and UFP-only modes, rather than implying that the modes DFP/UFP can "only" be configured in those specific cases.

    Best regards,

    Marc Ledesma

  • 0 in reply to Marc Ledesma
    TI__Mastermind 26310 points

    Hi Marc,

    The resistor on the PORT pin should set the initial settings for the register in I2C mode, but after that, modifying the register should change the bits accordingly. Any resistors on the PORT pins should only set the default, and should not stop the value from changing if ADDR is set accordingly.

    Marc Ledesma said:
    I would also like to confirm whether, in the first sentences of sections 7.3.1 and 7.3.2, when it says "DFP only" and "UFP only," it refers to the DFP-only and UFP-only modes, rather than implying that the modes DFP/UFP can "only" be configured in those specific cases.

    This wording here is just meant to indicate it will only support DFP or only support UFP when set accordingly. It does not mean it can only be set via the resistor on the PORT pin.

    Please let me know if you have any other questions.

    Thanks,

    Ryan