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TCA9536: Unused pin

cafain
Mastermind 6365 points
Part Number: TCA9536

Hi staff

Handling of unused pins.

Currently unused pins are open. Is there any recommended connection method such as wiring unused pins to the ground?

Unused pins are P1 and P2. (We are considering whether P3 is unnecessary.)

The setting is Configuration (0x03), the port P0 used is set as input (1), and the others are set as output (0).

best regards

cafain

  • 0
    Guru 243120 points

    Unused outputs should be left open. Unused inputs must not float, but this is prevented by the integrated pull-up resistors, which are enabled by default.

  • +1 in reply to Clemens Ladisch
    TI__Mastermind 47895 points

    Thanks Clemens!

    Hi Cafain,

    Keep in mind that because the pull-up enable configuration is shared between all pins, this means that if the pull-ups are disabled for the used pins, the unused pins need to be configured as outputs to avoid true floating inputs. If the pull-ups are to be left enabled, it would be fine to leave the unused pins floating. If you don't want to worry about any of these states, it would also be possible to include external pull-ups on these unused pins. 

    Let us know if you have any more questions.

    Regards,
    Eric Schott