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Add 32 Buttons With Just 2 Pins With MCP23017 Expander

March 19, 2026June 1, 2020 by ElectroBrandon

I need about 40 buttons for my synth project.  I’m trying to run the entire synth with a single STM32 Blue Pill.  I’ve already shown how I can run 256 LEDs with 3 pins LINK IT HERE.  Since the MCP23017 is I2C, I could possibly run 128 buttons on 2 pins.  For now, I’m just … Read more

Categories Electronics, Programming Tags button, expander, MCP23017

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