#include "mbed.h"
//#include <LiquidCrystal.h>
#include "TextLCD.h"
 
//int Htime;              //integer for storing high time
//int Ltime;              //integer for storing low time
//float Ttime;            //integer for storing total time of a cycle
volatile int    hTime;                    //integer for storing high time
volatile int    lTime;                    //integer for storing low time
int             tTime;                    //integer for storing total time of a cycle
float           frequency;                //storing frequency
volatile bool   dataAvailable = false;    //flag to indicate that new data is available
volatile bool   hTimeAvailable = false;   //flag to indicate that new high time is available
volatile bool   riseDetected = false;     //flag to indicate detection of signal rising edge
//LiquidCrystal lcd(A2, A3, A4, 4, 3, 2); // RS, E, D4, D5, D6, D7
TextLCD         lcd(A2, A3, A4, D4, D3, D2, TextLCD::LCD16x2);  // RS, E, D4, D5, D6, D7
/*
void setup()
{
    pinMode(8,INPUT);
    lcd.begin(16, 2);
}
*/
InterruptIn     input(D8);  //signal input pin
Timer           timer;      //timer used for measurement
 
/**
 * @brief   Interrupt Service Routine (ISR)
 * @note    Called on input signal rising edge
 * @param
 * @retval
 */
void onRise()
{
    lTime = timer.read_us();        //read input signal's low time
    timer.reset();                  //reset the timer and start measuring high time
    riseDetected = true;            //flag that signal rising edge was detected
    dataAvailable = hTimeAvailable; //flag that new data is available
    hTimeAvailable = false;         //reset the flag for next use in falling edge ISR
}
 
/**
 * @brief   Interrupt Service Routine (ISR)
 * @note    Called on input signal falling edge
 * @param
 * @retval
 */
void onFall()
{
    if (riseDetected)
    {
        hTime = timer.read_us();    //read input signal's high time
        timer.reset();              //reset the timer and start measuring low time
        riseDetected = false;       //reset the flag for next use in rising edge ISR
        hTimeAvailable = true;      //flag that 'high' time is available
    }
}
 
int main()
{
    //setup();
    input.rise(&onRise);            //attach a function to be called on signal rising edge
    input.fall(&onFall);            //attach a function to be calle on signal falling edge
    lcd.cls();
    lcd.printf("Connect a signal");
    timer.start();
 
    //void loop()
    while (true)
    {
        //check whether a measurement is complete
        if (dataAvailable)
        {
            dataAvailable = false;  //clear the flag for next use in rising edge ISR
            //lcd.clear();
            //lcd.setCursor(0,0);
            //lcd.print("Frequency of signal");
            lcd.cls();
            lcd.printf("Signal frequency");
 
            //hTime=pulseIn(8,HIGH);      //read high time
            //tTime=pulseIn(8,LOW);       //read low time
            tTime = hTime + lTime;
 
            frequency = 1000000 / (float)tTime;
            //lcd.setCursor(0,1);
            //lcd.print(frequency);
            //lcd.print(" Hz");
            lcd.locate(0, 1);
            lcd.printf("%f Hz", frequency);
            //delay(500);
            wait_ms(500);
        }
    }
}