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PCA9535: Initial Output to Low

Intellectual 2660 points

Replies: 6

Views: 65

Part Number: PCA9535

Hi E2E,

Good day!

Is there a way to set the initial state of the PCA9535 output to low?

Best regards,

Franz

  • Only by setting the configuration over I²C, or by adding pull-down resistors.

  • Hi Franz,

    The device doesn't have NVM (non-volatile memory) therefore in order to set the output low, you must write to the device every time you power it up (like Clemens pointed out), otherwise if you just need to weakly bias the pin to low you could use a pulldown resistor.

    -Bobby

  • In reply to BOBBY:

    Hi Clemens and Bobby,

    Thank you for your suggestions. This is well noted.

    Best regards,

    Franz

  • In reply to Franz Figueroa32:

    Hi Bobby,

    Just a follow-up question. As my customer's concern is that when the IO is configured as output, it has an initial state of high. Is it possible to configure the IO state to low before configuring it as output?

    Best regards.

    Franz

  • In reply to Franz Figueroa32:

    Clear the bits in the Output Port registers (2 and 3) before clearing the corresponding bits in the Configuration registers (6 and 7).

  • In reply to Franz Figueroa32:

    Hi Franz,

    I saw your email, as Clemen's has pointed out. The answer is yes. Set the output register values you want first after power up then set the configuration register to be an output.

    -Bobby

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