#include "mbed.h"
#include "FastPWM.h"

Serial pc(USBTX, USBRX); // tx, rx

FastPWM fastSquareWave(p26);

double T = .005;
double pWidth = .0025;
double changeFactor = .001;
double smallChangeFactor = .0000001;
double largeChangeFactor = .01;

double origT = .005;
double origPWidth = .5 * origT;

int main() {

    fastSquareWave.period(T);
    fastSquareWave.pulsewidth(pWidth);  
    
    pc.printf("Press 'u' to turn LED1 brightness up, 'd' to turn it down\n");
 
    while(1) {
        char c = pc.getc();
        
        // standard change factor
        if((c == 'u')) 
        {
            T -= changeFactor;
            pWidth = .5 * T;
        }
        if((c == 'd')) 
        {
            T += changeFactor;
            pWidth = .5 * T;
        }
        
        // small change factor
        if((c == 'q'))
        {
            T -= smallChangeFactor;
            pWidth = .5 * T;
        }
        if((c == 'w'))
        {
            T += smallChangeFactor;
            pWidth = .5 * T;
        }
        
        // large change factor
        if((c == 'e'))
        {
            T -= largeChangeFactor;
            pWidth = .5 * T;
        }
        if((c == 'r'))
        {
            T += largeChangeFactor;
            pWidth = .5 * T;
        }    
        
        if(T < 0.001)
        {
            pc.printf("Too low, use larger change factor\n");
            T = origT;
            pWidth = origPWidth;
        }     
        
        double currentFreq = 1 / T;
        pc.printf("Current Frequency: %f Period: %f\n", currentFreq, T);
        
        fastSquareWave.period(T);
        fastSquareWave.pulsewidth(pWidth);          
 
    }       
}