ADC multi-button

Designing too many matrix buttons will easily occupy too many IO ports. Is there a way to process multiple buttons with one IO port? In fact, there is, that is the ADC button.
The principle of the ADC button is to convert analog signals into digital signals. When a button is pressed, an analog voltage signal will be generated. Connect the high-level end of the button to the IO port with the ADC pin, and connect a corresponding resistor in series before each button.
When each button is pressed, the potential of the pin will change. When different buttons are pressed, the potential collected by the ad is different, so different buttons can be distinguished according to different potentials.
The principle is essentially resistor voltage division. The voltage value is changed by pressing different buttons, and then the ADC pin collects the corresponding voltage, and then a judgment can be made to realize the button function. ![1689424813011.png]