demo.ino

#include "L9110.h"

L9110 bridge;

void setup() 
{
    // Begin the bride, setting pins. Pins must be 4 of A0, A1, A4, A5, A6, A7, D0 and D1
    bridge.begin(A0,A1,D0,D1);
}

void loop() 
{
    // Speed up A
    for(int i = 0; i < 100; i += 20)
    {
        bridge.setSpeed('A', i);
        delay (2000);
    }
    
    // Slow down A
    for(int i = 100; i > 0; i -= 20)
    {
        bridge.setSpeed('A', i);
        delay (2000);
    }
    
    // Speed up B
    for(int i = 0; i < 100; i += 20)
    {
        bridge.setSpeed('B', i);
        delay (2000);
    }
    
    // Slow down B
    for(int i = 100; i > 0; i -= 20)
    {
        bridge.setSpeed('B', i);
        delay (2000);
    }
}

L9110.cpp

#include "L9110.h"
#include "spark_wiring.h"

///////////////////////////////////////////
/// Public
//////////////////////////////////////////

/// Constructor
L9110::L9110() { }

/// Destructor
L9110::~L9110() { }

/// Begin
void L9110::begin(int fwdPinA, int bwdPinA, int fwdPinB, int bwdPinB)
{
    _fwdPinA = fwdPinA; 
    _bwdPinA = bwdPinA;
    
    _fwdPinB = fwdPinB; 
    _bwdPinB = bwdPinB;
    
    _initMotor(_fwdPinA, _bwdPinA);
    _initMotor(_fwdPinB, _bwdPinB);
}

/// Set motor speed from -100 to + 100
void L9110::setSpeed(char motor, int speed)
{
    if(motor == 'A')
    {
        _setMotorSpeed(_fwdPinA, _bwdPinA, speed);
    }
    else if (motor == 'B')
    {
        _setMotorSpeed(_fwdPinB, _bwdPinB, speed);
    }
}

/// Stop a motor
void L9110::stop(char motor)
{
    setSpeed(motor, 0);
}

///////////////////////////////////////////
/// Private
//////////////////////////////////////////

/// Initialize motor pins
void L9110::_initMotor(int fwdPin, int bwdPin)
{
    //Set control pins to be outputs
    pinMode(fwdPin, OUTPUT); 
    pinMode(bwdPin, OUTPUT);
  
    //set motoR to run at (0/255 = 0)% duty cycle (stopped)
    digitalWrite(fwdPin, 0); 
    digitalWrite(bwdPin, 0);
}

/// Set motor speed from -100 to + 100
void L9110::_setMotorSpeed(int fwdPin, int bwdPin, int speed)
{
    int throttle = map(abs(speed),0,100,0,255);
    
    if(speed > 0)
    {
        analogWrite(fwdPin, throttle);
        digitalWrite(bwdPin, 0);
    }
    else if(speed < 0)
    {
        digitalWrite(fwdPin, 0);
        analogWrite(bwdPin, throttle);
    }
    else
    {
        digitalWrite(fwdPin, 0);
        digitalWrite(bwdPin, 0);
    }
}

L9110.h

#ifndef L9110_h
#define L9110_h

class L9110
{
  public:
    L9110();
    ~L9110();

    void begin(int fwdPinA, int bwdPinA, int fwdPinB, int bwdPinB);

    void setSpeed(char motor, int speed); // Set the speed of a selected motor, range: -100 to +100
    void stop(char motor);

  private:
    int _motoSpeedA;
    int _motoSpeedB;
    
    int _fwdPinA;
    int _bwdPinA;
    int _fwdPinB;
    int _bwdPinB;
    
    void _initMotor(int fwdPin, int bwdPin);
    void _setMotorSpeed(int fwdPin, int bwdPin, int speed);
};
#endif