File content as of revision 1:26267401354a:

#include "mbed.h"
#include "uLCD_4DGL.h"
#include "rtos.h"
#include "stdio.h"
#include "max31855.h"

uLCD_4DGL uLCD(p9,p10,p11); // serial tx, serial rx, reset pin;
SPI thermoSPI(p5,p6,p7); // setup SPI interface
max31855 max1(thermoSPI, p20); //setup max31855 interface
Mutex lcd_mutex; // mutex to make the lcd lib thread safe
Semaphore four_slots(1); //Activate semaphore
DigitalOut toggle(p30); // toggle for Nichrome wire SSR
DigitalIn up(p19); // User pushbutton up controller
DigitalIn down(p18); // User pushbutton down button controller

int settemp = 75; // initial temperature set
float ftemperature = 0; // float variable for temperature
float ctemperature = 0; // float variable for temperature

// Thread 1: print the elapsed time on line 1 of the uLCD (i.e., HH:MM:SS)
void elapsedtime(void const *args) { //elapsed timer for when program starts
    int s = 00; //seconds
    int m = 00; //minutes 
    int h = 00; //hours
    
    while(true){
        s++; 
        if(s>59){
           s=00;
          m++;
         }
         if(m>59){
           m=00;
           h++;
         }
       four_slots.wait(); // lock screen resource
       //lcd_mutex.lock();
        uLCD.color(0xFFFF00); //set text color
        uLCD.locate(0,0); //col,row location of text
        wait(0.1); 
        uLCD.printf("ET: %2d:%2d:%2d", h,m,s); // display time
        //lcd_mutex.unlock();
        four_slots.release(); //unlock screen resource
        Thread::wait(1000); // update once per secon
    }
}


// Thread 2: print the temperature from the thermocouple - MAX31855 device
void thermoread(void const *args) { //line 2
    while(true){
        if (max1.ready()==1){
            ctemperature = max1.read_temp(); //Get the reading
            ftemperature = (ctemperature)*(9.0/5.0)+32.0;
            four_slots.wait();    
            uLCD.color(0xFFFF00);
            uLCD.locate(0,2); //col,row
            wait(0.1);
            uLCD.printf("Current Temp. F");
            uLCD.locate(0,3); //col,row
            uLCD.printf("%4.2f", ftemperature);
            four_slots.release(); 
        }
    }
}

// Thread 3: read in user input from buttons..
void thermoset (void const *args) { //
    while(true){
        if (up==1){
            settemp += 1;
            four_slots.wait();    
            uLCD.color(0xFFFF00);        
            uLCD.locate(0,5); //col,row
            uLCD.printf("Set Temp. F");
            uLCD.locate(0,6); //col,row
            uLCD.printf("%d",settemp);
            four_slots.release(); 
            wait(.5);
        }
        if (down==1){
            settemp -= 1;
            four_slots.wait();    
            uLCD.color(0xFFFF00);        
            uLCD.locate(0,5); //col,row
            uLCD.printf("Set Temp. F");
            uLCD.locate(0,6); //col,row
            uLCD.printf("%d",settemp);
            four_slots.release();
            wait(.5); 
        }
    }
}


int main() {
    max1.initialise(); //initialize thermocouple IC    
    uLCD.baudrate(3000000); //set LCD baudrate
    Thread t1(elapsedtime); //run elapsed time counter
    Thread t2(thermoread); //read and display temperature from thermocouple
    Thread t3(thermoset); //runs thread that checks to see if user has changed the temperature setpoint
    
    while(1){ //hystersis program
            if(ftemperature < settemp-1){ //condition for 1 degree under
                toggle=1; //turn on ssr for nichrome wire
            }
            if(ftemperature > settemp+1){  //condition for 1 degree over
                toggle=0; //turn off ssr for nichrome wire
            }
            wait(1); //check every 1 second
        }
}