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Linux/PCA9535: PCA9535 GPIO configure

Leif Tai
Prodigy 20 points
Part Number: PCA9535

Tool/software: Linux

Hi

PCA9535 is 16-bit I/O expander, if GPIO no using, can I configure to input pull down?

Thanks.

Leif

  • 0
    TI__Guru 62920 points
    Hi Leif,

    If a port is unused, it can be configured as an input and then pulled high or low externally (e.g., using a resistor). Or, the unused port could be configured as an output (either at a high level or low level). There is no way to configure an input to pull up or down internally, though.

    Regards,
    Max
  • 0 in reply to Miguel Robertson
    Prodigy 20 points

    Hi Max

    If our Software no configured unused port, what is their default status ? floating....?

  • 0 in reply to Leif Tai
    TI__Guru 62920 points
    Leif,

    The default configuration is for each port to be configured as a high-impedance input. You can see the power-up default settings summarized in Table 3 of the datasheet. In your system, you could either pull these unused input ports high or low or re-configure them as outputs. Before they are configured as outputs, though, you may see higher supply current if the ports are left floating.

    Max