Hi, I have a school project where I need to make a working vault-door by reading out a 12 button display, with 3 inputs and 4 outputs. The columns are put in series, and the rows are put in series as well. All the column-pins are inputs with a pull up resistor. So, when nothing is pressed, all three…

12-keypad reading with 7 pins, I'm confused

LarryD October 6, 2021, 4:21pm 3

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