MikroElektronika MIKROE-3409, Analog Key Click for KMR221

Analog Key Click is an analog keyboard on a Click board™. It contains six tactile pushbuttons, used to select one of six different voltage levels. The idea behind this click is very simple: six resistors form a voltage divider. The resistors are connected in series between the VCC and the GND. Each button selects one of the six middle taps, allowing six different voltage levels to be selected. The voltage is available at the AN pin of the mikroBUS™, which is additionally protected by an operational amplifier, configured as a buffer. This allows both protection and a proper impedance at the analog input pin of the microcontroller.