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TCA6424A: Issue with the use of 400 GPIO

David C
Expert 3350 points
Part Number: TCA6424A
Other Parts Discussed in Thread: TCA9555, TCA9535

Hello,

 I was hoping to make use of the TI TCA6424A, but after reading the datasheet more carefully, I noticed that instead of allowing the 7-bit address setting, it really only has one bit that can be toggled, so only two of these can be used in a design.  Am I interpreting that correctly?  Is there some other high pin count GPIO expander that would allow for a wider range of GPIO addressing?

Regards,

David

  • 0
    TI__Mastermind 49040 points
    Hey David,

    "I noticed that instead of allowing the 7-bit address setting, it really only has one bit that can be toggled, so only two of these can be used in a design. Am I interpreting that correctly?"

    -You're interpretation is correct. This device has only two configurable addresses. Though in a design, you could potentially have more if you utilize an I2C switch which corrects issues with address conflicts.

    "Is there some other high pin count GPIO expander that would allow for a wider range of GPIO addressing?"
    -If you do not want to use the I2C switch with the TCA6424A then the next possible solution to to use TCA9555 or TCA9535 however they have a maximum of 16 possible GPIOS versus the TCA6224A. Both these devices do allow for up to 8 configurable addresses.

    Thanks,
    -Bobby