File content as of revision 0:c9c80e03823a:

/* Libraries */
#include "mbed.h"
#include "TextLCD.h"

/* */
#define DELAY_M 50              //Delay before Measuring Voltage at ADC-Pin (TempNow)
#define TEMP_BASEGAIN 0.137931  //Temp which should equal 1mV - changed by TEMP_FACTOR
#define TEMP_OFFSET 0           //Offset of Temperature
#define CTRL_GAIN 10            //TempDifference to PWM-Value Gain
#define TEMP_FACTOR 1.5         //TEMP_BASEGAIN * TEMP_FACTOR = TEMP_GAIN

/*  */
Ticker dispRefresh;
TextLCD lcd (p18, p16, p11, p10, p9, p8); // rs, e, d4-d7
DigitalOut db5(p10);    //Data Pin 5 on LCD, used for Initialization
DigitalOut rw(p17);     //Read-Write Pin on LCD: LOW-->WRITE
PwmOut pHeat(p26);      //Heater-Pin 
AnalogIn adc(p20);      //ADC-Pin 10Bit
PwmOut pSpeaker(p25);   //Piezo-Speaker Pin
InterruptIn rotSw1(p35); //Pin 1 of Rotary Encoder
DigitalIn rotSw2(p33);   //Pin 2 of Rotary Encoder
InterruptIn rotSwB(p30);   //Button of Rotary Encoder
DigitalOut tempCtrlLED(LED1);

/* */
float TempNow = 0;      //Current Temperature Reading
float TempSet = 200;      //Set Temperature   
float pwmVal = 0;       //PWM-Value for Heater-Pin
float adcVal = 0;       //Value of ADC-Reading

/* */
void writeLCD();
void init4BitLCD();
void readTemp();
void calcPWM();
void RotEnc();
void RotBut();

int ticker = 500;
Ticker t;
void tick_1(){
    if(ticker > 0) ticker--;
}

int main() {
    //Initialize
    init4BitLCD();      //Set Display to 4 Bit-Mode
    rw = 0;             // Set Read/Write Pin to Write
    rotSw1.rise(&RotEnc);
    rotSwB.rise(&RotBut);
    pSpeaker.period_ms(2); //Set Speaker Frequency to 500Hz
    //pHeat = 0.1;   
    
    t.attach(&tick_1, 0.001);
    while(1) {
        readTemp();     //Read Temperature              - Done
        calcPWM();      //Calculate PWM-Value           - Done
        pHeat = pwmVal; //Write PWM-Value to Heater     - Done
        if(ticker == 0){
            writeLCD();     //Write To LCD                  - Done
            ticker = 500;
        }
        //Repeat
    }
}

void RotBut()
{tempCtrlLED = !tempCtrlLED;
 if (pSpeaker == 0){pSpeaker = 0.5;}
 else {pSpeaker = 0;}}
 
void RotEnc()
{
    if (rotSw2 == 0){TempSet++;}
    else if (rotSw2 == 1){TempSet--;}
    wait_ms(1);
    }

void calcPWM()
{
    pwmVal = ((TempSet - TempNow) * CTRL_GAIN) / 255; //Calculate PWM-Val.
    if (pwmVal > 1) pwmVal = 1;
    else if (pwmVal < 0) pwmVal = 0;
    }

void readTemp()
{   pHeat = 0;      //Switching Off Heater || Thermoelement --> No VoltageSupply
    wait_ms(DELAY_M);   //Waiting for a bit|| Low-Pass Filter --> Ready State
    adcVal = adc.read();    //Read ADC
    TempNow = adcVal*3300*(TEMP_BASEGAIN * TEMP_FACTOR) + TEMP_OFFSET;   //Calculate current Temperature
    pHeat = pwmVal;     //Re-Activate Heater Pin
    }

void writeLCD()
{   char cHeat;
    if(pwmVal > 0.5){cHeat = 'H';}
    else{cHeat = ' ';}
    lcd.cls();
    lcd.printf("Set: %.0f C   %c\nNow: %.0f C", TempSet, cHeat, TempNow);}
    
void init4BitLCD()
{   db5 = 1; wait_ms(1); lcd.cls();}