File content as of revision 0:0af5376a3506:

#include "mbed.h"
#include "math.h"

DigitalIn button1(D8);
AnalogIn potMeterIn(A1);

float motor1DirectionPin;
float motor1MagnitudePin;
float referenceVelocity;  // in rad/s

float GetReferenceVelocity()
{
    // Returns reference velocity in rad/s. 
    // Positive value means clockwise rotation.
    const float maxVelocity=8.4; // in rad/s of course!    
    
    if (button1)   
        {
        // Clockwise rotation      
        referenceVelocity = potMeterIn * maxVelocity;
        } 
        else 
        {
        // Counterclockwise rotation       
        referenceVelocity = -1*potMeterIn * maxVelocity;  
        }
    return referenceVelocity;
}


void SetMotor1(float motorValue)
{
    // Given -1<=motorValue<=1, this sets the PWM and direction
    // bits for motor 1. Positive value makes motor rotating
    // clockwise. motorValues outside range are truncated to
    // within range
    if (motorValue >=0) motor1DirectionPin=1;
        else motor1DirectionPin=0;
    if (fabs(motorValue)>1) motor1MagnitudePin = 1;
        else motor1MagnitudePin = fabs(motorValue);

}
float FeedForwardControl(float referenceVelocity)
{
    // very simple linear feed-forward control
    const float MotorGain=8.4; // unit: (rad/s) / PWM
    float motorValue = referenceVelocity / MotorGain;
    return motorValue;
}
        
void MeasureAndControl(void)
{
    // This function measures the potmeter position, extracts a
    // reference velocity from it, and controls the motor with 
    // a simple FeedForward controller. Call this from a Ticker.
    float referenceVelocity = GetReferenceVelocity();
    float motorValue = FeedForwardControl(referenceVelocity);
    SetMotor1(motorValue);
}

int main()
{
    while (true) 
    {
    GetReferenceVelocity();
    FeedForwardControl(referenceVelocity);
    MeasureAndControl();
    printf("%f", referenceVelocity);
    
    }
}