#include<avr/io.h> //standard AVR header
#include<util/delay.h> //delay header
#include<avr/interrupt.h> //interrupt header

#define F_CPU 12000000

#define KEY_PRT PORTB//keyboard PORT
#define KEY_DDR DDRB//keyboard DDR
#define KEY_PIN PINB//keyboard PIN

#define LCD_DPRT PORTD //LCD DATA PORT
#define LCD_DDDR DDRD //LCD DATA DDR
#define LCD_DPIN PIND //LCD DATA PIN
#define LCD_CPRT PORTC// LCD COMMANDS PORT
#define LCD_CDDR DDRC//LCD COMMANDS DDR
#define LCD_CPIN PINC//LCD COMMANDS PIN
#define LCD_RS 0 //LCD RS
#define LCD_RW 1 //LCD RW
#define LCD_EN 7 //LCD EN

void lcdinit(void);
void lcd_gotoxy(unsigned char,unsigned char );
void lcdprint(char*);
void lcdcommand(unsigned char);
void delay_us(unsigned int);
void delay_ms(unsigned int );
void lcddata(unsigned char);
unsigned char keypadcall(void);

unsigned char keypad[4][4]={'A','3','2','1',//keypad declaration as a 4x4 matrix
'B','6','5','4',
'C','9','8','7',
'D','#','0','*'};

void main(void)
{
int ADCH_temp,x,y,a,b,c,d,e,ADC_temp=0,i;
DDRA=0b00000110; //PINA1 and PINA2 are outputs and the rest of the pins of PORTA are inputs
ADCSRA=0X87; //make ADC enable and select clk/128*
ADMUX=0XE0; //2.56Vref ,single ended channel ADC0,data will be left justified
sei(); //enable interrupt
lcdinit(); //LCD initialisation function
lcd_gotoxy(1,1); //LCD cursor positioning function
lcdprint("set temp="); //LCD print function
delay_us(1000); //wait
a= keypadcall(); //keypad call for the first digit of temperature
b= keypadcall(); //keypad call for the second digit of temperature
c=atoi(&a); //conversion from character to integer
d=atoi(&b); //conversion from character to integer
e=10*c+d; //the set temp entered finally converted to integer form

while(1) //stay here forever

{ ADC_temp=0;
for(i=0;i<16;i++) //do the ADC conversion 16 times to improve the accuracy
{
ADCSRA|=(1<<ADSC); //start conversion
while((ADCSRA&(1<<ADIF))==0); //wait for end of conversion,ADIF flag set
ADCH_temp=ADCH; //the variable holds the current temperature
ADC_temp+=ADCH_temp; //accumulate results(16 samples)
}
ADC_temp=ADC_temp>>4; //average the 16 samples
x=ADC_temp/10+48; //required to convert the temperature(first digit)

to ascii(decimal) value in order to display it on LCD

y=ADC_temp%10+48; //required to convert the temperature(second digit) to

ascii(decimal) value in order to display it on LCD

lcd_gotoxy(1,2);
lcddata(x); //pass the ascii value of first digit in order to display it on the LCD
lcddata(y); //pass the ascii value of second digit in order to display it on the LCD
lcdprint("deg celcius");
delay_us(1000); //wait
if(ADC_temp<=(e-2)) //if current temp is 2 degree celsius less than the set temperature
PORTC=PORTC|0b01000000; //turn on the heater connected to PORTA6
if(ADC_temp==e) //if current temp is equal to the set temperature
{
PORTC=PORTC&0b00000000; //turn off the heater
PORTA=PORTA&0b00000000; //turn off the fan
}
if (ADC_temp>=(e+2)) //if current temp is 2 degree celsius more than the set temperature
PORTA=PORTA|0b00000100; //turn on the fan


}


}

void lcdinit()
{
LCD_DDDR= 0XFF;
LCD_CDDR= 0XFF;
LCD_CPRT &=~(1<<LCD_EN); //LCD_EN=0
delay_us(2000);//wait for init
lcdcommand(0X38); //init LCD 2 line, 5X7 matrix
lcdcommand(0x0E); //display on,cursor on
lcdcommand(0X01); //clear LCD
delay_us(2000);//wait
lcdcommand(0X06); //shift cursor right
}

void lcdcommand(unsigned char cmnd)
{
LCD_DPRT=cmnd; //send cmnd to data port
LCD_CPRT&=~(1<<LCD_RS); //RS=0 for command
LCD_CPRT&=~(1<<LCD_RW); //RW=0 for write
LCD_CPRT|=(1<<LCD_EN); //EN=1 for H-to-L pulse
delay_us(1); //wait to make enable wide
LCD_CPRT&=~(1<<LCD_EN); //EN=0 for H-to-L pulse
delay_us(100); //wait to make enable wide

}


void delay_us(unsigned int d)//delay in micro secs
{
_delay_us(d);
}

void delay_ms(unsigned int d)/*delay in milli secs*/
{

_delay_ms(d);
}


void lcd_gotoxy(unsigned char x,unsigned char y)
{

unsigned char firstcharadr[]={0x80,0xC0,0x94,0xD4};
lcdcommand(firstcharadr[y-1]+x-1);
delay_us(100);
}

void lcdprint(char *str)
{

unsigned char i=0;
while(str[i]!=0)
{
lcddata(str[i]);
i++;
}

}

void lcddata(unsigned char data)
{
LCD_DPRT=data; //send data to data port
LCD_CPRT|=(1<<LCD_RS); //RS=1 for data
LCD_CPRT&=~(1<<LCD_RW); //RW=0 for write
LCD_CPRT|=(1<<LCD_EN); //EN=1 for H-to-L pulse
delay_us(1); //wait to make enable wide
LCD_CPRT&=~(1<<LCD_EN); //EN=0 for H-to-L pulse
delay_us(100); //wait to make enable wide
}

unsigned char keypadcall(void)
{
unsigned char colloc,rowloc;
//keyboard routine.this sends the ASCII code for the pressed key to PORTB
KEY_DDR=0XF0;
KEY_PRT=0XFF;
while(1) //repeat forever
{do
{
KEY_PRT &=0X0F; //ground all rows at once
colloc=(KEY_PIN&0X0F); //read columns
}while(colloc!=0X0F); //check until all keys released

do
{
do
{ delay_ms(20); //call delay
colloc=(KEY_PIN&0X0F); //see if any key is pressed
} while (colloc==0X0F); //keep checking for key press

delay_ms(20); //call delay for debounce
colloc=(KEY_PIN&0X0F); //read columns
} while (colloc==0X0F); //wait for key press

while(1)

{KEY_PRT=0XEF;//ground rows
colloc=(KEY_PIN&0X0F); //read all the columns
if(colloc!=0X0F) //col detected
{
rowloc=0; //save row loc
break; //exit while loop
}


KEY_PRT=0XDF; //ground row1
colloc=(KEY_PIN&0X0F); //read the columns
if(colloc!=0X0F) //col detected
{
rowloc=1; //save row loc
break; //exit while loop
}

KEY_PRT=0XBF; //ground row 2
colloc=(KEY_PIN&0X0F); //read the columns
if(colloc!=0X0F) //col detected
{
rowloc=2; //save row loc
break; //exit while loop
}

KEY_PRT=0X7F; //ground row 3
colloc=(KEY_PIN&0X0F); //read the columns
rowloc=3; //save row loc
break;//exit while loop
}
//check column and send the result for display on LCD,
// also return the value to main function in order to convert the character into integer
if (colloc==0X0E)
{lcddata(keypad[rowloc][0]);
return(keypad[rowloc][0]);
}

else if (colloc==0x0D)
{lcddata(keypad[rowloc][1]);
return(keypad[rowloc][1]);
}

else if (colloc==0X0B)
{lcddata(keypad[rowloc][2]);
return(keypad[rowloc][2]);
}
else
{lcddata(keypad[rowloc][3]);
return(keypad[rowloc][3]);
}

break;//exit while loop
}



}