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TCA9539: TCA9539RTWR output status

Lisa Xu
Intellectual 505 points
Part Number: TCA9539

Tool/software:

Dear TI Team:

I just want to check IO expander_TCA9539RTWR output status.

When one Port of TCA9539RTWR is set to output, it will have 3 status: High,low, and High impedance, Right?

Best Regards

Lisa

  • +1
    Guru 294720 points

    A pin that is configured as output will drive either high or low.
    If you want a high-impedance pin, you have to configure it as input.

  • 0
    TI__Mastermind 36463 points

    Hi Lisa,

    I agree with Clemens here. Please see his response on the output state. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    Intellectual 505 points

    Hi Tyler,Clemens:

    Got your points.mostly IC  just has two status when set to output, but I saw some will support high impedance(high & low mosfet both off).

    And check from the block diagram of TCA9539RTWR, I assume it will also have status with both Q1 & Q2 off when set to output.

    BR

    Lisa

  • 0 in reply to Lisa Xu
    Guru 294720 points

    When the pin is configured as input, the configuration register's Q output is high and /Q is low, so Q1 and Q2 are off.

  • +1 in reply to Lisa Xu
    TI__Mastermind 36463 points

    Hi Lisa,

    When the I/O pin is configured to be an OUTPUT, either Q1 or Q2 will be turned ON depending on the values in the output port register (0x02 & 0x03). 

    If you desire the I/O pin to have Q1 and Q2 disable, configure the I/O pin to be a high-z input through the configuration registers (0x06 & 0x07).

    Regards,

    Tyler