This library controls the L9110 2 channel motor driver using a soft Pulse Width Modulation.
var gpioController = GpioController.GetDefault();
var speedPinNumber = 18; // input A is used to control speed
var directionPinNumber = 21; // input B is used to control direction
var dutyCycle = 0.5d;
var l9110 = new L9110(gpioController, speedPinNumber, directionPinNumber);
l9110.StartLow(dutyCycle); // input B is low; clockwise
l9110.Stop();
l9110.StartHigh(dutyCycle); // input B is high; anticlockwise
l9110.Stop();