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TCAL6416: Hiz mode

Fred Cheng
Expert 5970 points
Part Number: TCAL6416


Hi team,

 

we know TCAL6416 has push-pull and some output can support open drain,

but we also want to know does the push-pull stay in HiZ  or LOW when there's no input command perceived ?

  • 0
    TI__Guru 54928 points

    Hi Fred,

    Once a I/O pin is configured as an OUTPUT through the configuration register, it outputs a HIGH or LOW logic level depending on the output port register value. 

    If you want high-z, then convert the I/O to an INPUT through the configuration register. This makes the pin a true high-z CMOS input. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    TI__Expert 5970 points

    Hi Tyler,

    so there’s no three state output option for push-pull?

    since we are considering the possibility when open-drain  output number more than 7, and if we wonder if push-pull output with external pull resistor can be open drain, that’s  why we want to know if output can be Hiz.

  • 0 in reply to Fred Cheng
    TI__Guru 54928 points

    Hi Fred,

    If a Pxx pin is configured to OUTPUT, it only has two states, drive HIGH or drive LOW. There is no tri-state on a pin that is configured to OUTPUT. 

    To get a tri-state on the Pxx pin, configure the OUTPUT back to a CMOS high-z input with a external pull-up or pull-down resistor, or configure the internal PU/PD resistors through the registers. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    TI__Expert 5970 points

    Hi tyler,

    so you mean set Hiz input with external pull-up as steady state or default , and change command to turn it to LOW when needed?

  • 0 in reply to Fred Cheng
    TI__Guru 54928 points

    Hi Fred,

    I will respond later today. 

    Regards,

    Tyler

  • 0 in reply to Fred Cheng
    TI__Guru 54928 points

    Hi Fred,

    Fred Cheng said:
    so you mean set Hiz input with external pull-up as steady state or default , and change command to turn it to LOW when needed?

    What you described here is similar to an open-drain output. 

    Set high-z INPUT with external pull-up as steady state. (this is the logic high through the PU resistor to VCC).

    Change command to turn it to OUTPUT LOW - this converts the I/O to an OUTPUT, and pulls it LOW. 

    Regards,

    Tyler