Measuring the voltage on a resistor of a voltage divider. We use the pin GPIO17 for applying a \(3.3 V\)  tension to the series of three equal resistors, so that a \(1.1 V\)  voltage is expected between the two terminals of each resistor. We choose the resistor connected to GND and we connect the other terminal of the resistor to the channel CH0 of the ADC converter.