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I2C drive strength

Intellectual 480 points

Replies: 4

Views: 1454

Iv'e heard it's possible to change the pins drive strength.

Iv'e had several questions regarding this topic:

1. how exactly is the drive strength changed?

2. does the "pin mode" number sent to PinTypeI2C have any effect/connection to this (I aw different values for the SDA pin in different code examples I found)?

3. are there any negative implications to increasing the drive strength? any guidelines I should pay attention to?

Thanks in advance!

  • Tal,

    Please see below:

    1. how exactly is the drive strength changed?

    The drive strength changes by using this function

    PinConfigSet(ulPin,PIN_STRENGTH_2MA|PIN_STRENGTH_4MA,PIN_TYPE_STD);

    This function is called inside PinTypeI2C().

    2. does the "pin mode" number sent to PinTypeI2C have any effect/connection to this (I aw different values for the SDA pin in different code examples I found)?

    The Pin mode corrosponds to what peripheral you would like that pin to be muxed to. There is a table inside the CC3200 Datasheet that shows what the number should be for I2C.

    http://www.ti.com/lit/ds/symlink/cc3200.pdf

    3. are there any negative implications to increasing the drive strength? any guidelines I should pay attention to?

    The drive strength really just depends on what you are trying to control. the pull up or pull down usually can be a weak pull for Digital signals, and strong if your driving a LED or such device. 

    Let me know if that helps!

    VR

  • In reply to Vincent Rodriguez:

    Vincent - Thank you very much! This clarified the issue for me.
    One small followup - when you mentioned "PinConfigSet" routine, you wrote "PIN_STRENGTH_2MA|PIN_STRENGTH_4MA" as the second argument. The documentation mentions another option - "PIN_STRENGTH_6MA". Was it left out by mistake or is it not really allowed?

  • 12/11/17[LE]>unlock thread
  • In reply to Tal Ben Porath:

    Tal,

    No, it was not left out, you have multiple drive strengths that you can configure.  For more info, please refer to page 498 of http://www.ti.com/lit/ug/swru367c/swru367c.pdf

    Regards,

    VR

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