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TCA9555: TCA9555 At power On Pin as a Input.

Jithin potu
Prodigy 30 points
Part Number: TCA9555
Other Parts Discussed in Thread: TCA9535

Dear Sir,

I used TCA9555 Io Expander IC. At power on condition all pin as a input work but voltage available in IO pin? 

as per schematic Io port pull-up 100kohms though VCC.  

  • 0
    Guru 294230 points

    Yes; the datasheet says:

    The TCA9555 is identical to the TCA9535, except for the inclusion of the internal I/O pull-up resistor, which pulls the I/O to a default high when configured as an input and undriven.

  • 0
    TI__Mastermind 36353 points

    Jithin,

    TCA9555 will power up with p-ports configured to inputs, but each input will be pulled HIGH to VCC through the 100kohm pull-up resistor. 

    Regards,

    Tyler