About PCF8574T I/O Expander

I have read an article about PCF8574T
Now I would like to know WHAT is the operating principle of PCF8574T ?

If you know , please tell me ,thanks a lot ! :grinning:

I guess https://www.nxp.com/docs/en/data-sheet/PCF8574_PCF8574A.pdf should explain all you want to know.

Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project :wink: See About the Installation & Troubleshooting category.

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It enables you to access an extra 8 GPIO pins via I2C. You can add multiple devices, and configure each with a different address (3 bits variable) so you can have up to 8x8 pins available. Here is the schematic

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Very kind of you!

Thank you very much!