#include <avr/io.h>

#define F_CPU 8000000UL // 8 MHz

#include <util/delay.h>

#include <math.h>

#include <avr/interrupt.h>

#include <avr/signal.h>

#define N 600 //number of sample for calculate the average value of the temperature

#define MAX_INIT 100000 //number of sample to find the maximun at the begininnig of the pulse

#define perc 0.6 //percentual for threshold

#define perc2 0.3 //percentual for threshold2

#define N_average 1 //how many frequency pulse values to make an average

#define N_reset 1 //number of dislayed values before come back to pulse initialization

//void _delay_ms (double __ms)

//void _delay_us (double __us) included in delay.h

int EXIT;

char MODE;

int freq_prev;

void set_pin(){

//at the beginning of the program the direction (and other functions)

//of pins is setted

DDRA=0x00; //port A input ADC

DDRB=0xff;

DDRC=0xc0;

DDRD=0xf2;

}

void write_pin(char letter, unsigned long numb, char value){

// usefull function for writing only one pin in a port without

// modifying the other pins value

//read the port, copy the value, modify pin and set again the register

char x; //x is a mask

x=(1 << numb);

switch (letter){

case 'A':

if (value == 1 ){

PORTA |= x; }

else{

x=~x;

PORTA &= x;}

break;

case 'B':

if (value == 1 ){

PORTB |= x; }

else{

x=~x;

PORTB &= x;}

break;

case 'C':

if (value == 1 ){

PORTC |= x; }

else{

x=~x;

PORTC &= x;}

break;

case 'D':

if (value == 1 ){

PORTD |= x; }

else{

x=~x;

PORTD &= x;}

break;

}

}

void write_data_LCD(char data) //enable signal and send data to DBx

{ PORTB=data; }

// Function that configures the LCD to receive instructions

void set_write_IR() { //set RS and RW for those operation

write_pin('D',PD4,0); //RS=0

write_pin('D',PD5,0); //RW=0

}

// Function that configures the LCD to receive data

void set_write_DR(){

write_pin('D',PD4,1); //RS=1

write_pin('D',PD5,0); //RW=0

}

void enable(){ //set E=1 of LCD

write_pin('D',PD6,1);

}

void disable(){ //E=0 of LCD

write_pin('D',PD6,0);

}

void initial_LCD(){

enable();

set_write_IR();

write_data_LCD(0x38); //function set -> 8bit mode

disable();

enable();

_delay_us (40);

write_data_LCD(0x01); //clear display

disable();

enable();

_delay_ms (2);

write_data_LCD(0x02); //cursor home

disable();

enable();

_delay_ms (2);

write_data_LCD(0x0c); //display on/off -> on, no cursor, no blinking

disable();

enable();

_delay_us (40);

}

void clear_LCD(){

set_write_IR();

write_data_LCD(0x01); //clear display

disable();

enable();

_delay_ms (50);

}

void next_line_LCD(){

set_write_IR();

write_data_LCD(0b11000000); //cursor shifted to the start of the second line

disable();

enable();

_delay_us (400);

}

//function take a character and write on LCD

void write_char(char letter){

char t;

switch (letter){

case '0':

t=0x30;

break;

case '1':

t=0x31;

break;

case '2':

t=0x32;

break;

case '3':

t=0x33;

break;

case '4':

t=0x34;

break;

case '5':

t=0x35;

break;

case '6':

t=0x36;

break;

case '7':

t=0x37;

break;

case '8':

t=0x38;

break;

case '9':

t=0x39;

break;

case '-': // The "-" symbol will be considered a white space

t=0x20;

break;

case 'A':

t=0x41;

break;

case 'B':

t=0x42;

break;

case 'C':

t=0x43;

break;

case 'D':

t=0x44;

break;

case 'E':

t=0x45;

break;

case 'F':

t=0x46;

break;

case 'G':

t=0x47;

break;

case 'H':

t=0x48;

break;

case 'I':

t=0x49;

break;

case 'J':

t=0x4a;

break;

case 'K':

t=0x4b;

break;

case 'L':

t=0x4c;

break;

case 'M':

t=0x4d;

break;

case 'N':

t=0x4e;

break;

case 'O':

t=0x4f;

break;

case 'P':

t=0x50;

break;

case 'Q':

t=0x51;

break;

case 'R':

t=0x52;

break;

case 'S':

t=0x53;

break;

case 'T':

t=0x54;

break;

case 'U':

t=0x55;

break;

case 'V':

t=0x56;

break;

case 'W':

t=0x57;

break;

case 'X':

t=0x58;

break;

case 'Y':

t=0x59;

break;

case 'Z':

t=0x5a;

break;

case 'a':

t=0x61;

break;

case 'b':

t=0x62;

break;

case 'c':

t=0x63;

break;

case 'd':

t=0x64;

break;

case 'e':

t=0x65;

break;

case 'f':

t=0x66;

break;

case 'g':

t=0x67;

break;

case 'h':

t=0x68;

break;

case 'i':

t=0x69;

break;

case 'j':

t=0x6a;

break;

case 'k':

t=0x6b;

break;

case 'l':

t=0x6c;

break;

case 'm':

t=0x6d;

break;

case 'n':

t=0x6e;

break;

case 'o':

t=0x6f;

break;

case 'p':

t=0x70;

break;

case 'q':

t=0x71;

break;

case 'r':

t=0x72;

break;

case 's':

t=0x73;

break;

case 't':

t=0x74;

break;

case 'u':

t=0x75;

break;

case 'v':

t=0x76;

break;

case 'w':

t=0x77;

break;

case 'x':

t=0x78;

break;

case 'y':

t=0x79;

break;

case 'z':

t=0x7a;

break;

case ':':

t=0x3a;

break;

case '?':

t=0x3f;

break;

case '.':

t=0x2E;

break;

}

write_data_LCD(t);

disable();

enable();

_delay_us (40);

}

void write_initial_screen(){

set_write_IR(); //entry mode of this text

write_data_LCD(0x06);

disable();

enable();

_delay_us(40);

set_write_DR(); //write Select Measurment

write_char('S');

write_char('e');

write_char('l');

write_char('e');

write_char('c');

write_char('t');

write_char('-');

write_char('M');

write_char('e');

write_char('a');

write_char('s');

write_char('u');

write_char('r');

write_char('e');

next_line_LCD();

set_write_DR(); //write Select Measurment

write_char('1');

write_char('T');

write_char('e');

write_char('m');

write_char('p');

write_char('-');

write_char('-');

write_char('-');

write_char('2');

write_char('P');

write_char('u');

write_char('l');

write_char('s');

write_char('e');

}

void write_temp_screen(){

set_write_IR(); //entry mode of this text

write_data_LCD(0x06);

disable();

enable();

_delay_us(40);

set_write_DR();

write_char('T');

write_char('e');

write_char('m');

write_char('p');

_delay_ms (500);

}

void write_pulse_screen(){

set_write_IR(); //entry mode of this text

write_data_LCD(0x06);

disable();

enable();

_delay_us(40);

set_write_DR();

write_char('P');

write_char('u');

write_char('l');

write_char('s');

write_char('e');

_delay_ms (500);

}

//function used when the heart rate value is not correct

void write_error_screen(){

set_write_IR(); //entry mode of this text

write_data_LCD(0x06);

disable();

enable();

_delay_us(40);

set_write_DR();

write_char('W');

write_char('a');

write_char('i');

write_char('t');

write_char(' ');

write_char(' ');

}

int buttom(){

//it is a function that returns 1 if you press the button 1 and returns

//2 if you press the button 2. wait until one buttom is released.

char flag = 0;

char input;

while (flag==0){

input = PINC&0x01 ;

if (input== 0x00 ){

_delay_ms(200);

while (input== 0x00){input = PINC&0x01 ;}; //contrilling if the last bit is equal to 0

flag = 1; }

else {input = PINC&0x02 ;

if (input== 0x00 ){ //contrilling if the last bit is equal to 1

_delay_ms(200);

while (input== 0x00){input = PINC&0x02 ;};

flag = 2; }}

}

return flag;

}

//start the adc convertion

void start_conv(){

char t;

t= (1<<ADSC);

ADCSRA|=t;

}

//this show in the LCD a number between 0 to 1024 in a int variable

//It's necessary to convert the decimal number to different characters in order to be displayed

void send_int(int a, char meas){

char t1,t2,t3,t4,t5,t6;

t1 = a%10;

t2 = (a/10)%10;

t3 = (a/100)%10;

t4 = (a/1000)%10;

t5 = (a/10000)%10;

t6 = (a/100000)%10;

char p;

// start of the code necessary to do the serial communication

//send type of measure

while ((UCSRA & (1 << UDRE)) == 0) {}; //do nothing until buffer is empty

UDR = meas+0x30;

//send data

p=t6+0x30;

while ((UCSRA & (1 << UDRE)) == 0) {};

UDR = p;

p=t5+0x30;

while ((UCSRA & (1 << UDRE)) == 0) {};

UDR = p;

p=t4+0x30;

while ((UCSRA & (1 << UDRE)) == 0) {};

UDR = p;

p=t3+0x30;

while ((UCSRA & (1 << UDRE)) == 0) {};

UDR = p;

p=t2+0x30;

while ((UCSRA & (1 << UDRE)) == 0) {};

UDR = p;

p=t1+0x30;

while ((UCSRA & (1 << UDRE)) == 0) {};

UDR = p;

}

void write_int_LCD(int a ){

int t1,t2,t3,t4,t5,t6;

t1 = a%10;

t2 = (a/10)%10;

t3 = (a/100)%10;

t4 = (a/1000)%10;

t5 = (a/10000)%10;

t6 = (a/100000)%10;

char p;

p = t6;

if (p!= 0){

p+=0x30;

write_data_LCD(p);

disable();

enable();

_delay_us (40);

}

p = t5;

p+=0x30;

write_data_LCD(p);

disable();

enable();

_delay_us (40);

p = t4;

p+=0x30;

write_data_LCD(p);

disable();

enable();

_delay_us (40);

p = t3;

p+=0x30;

write_data_LCD(p);

disable();

enable();

_delay_us (40);

p = t2;

p+=0x30;

write_data_LCD(p);

disable();

enable();

_delay_us (40);

write_char('.'); //decimal dot

p = t1;

p+=0x30;

write_data_LCD(p);

disable();

enable();

_delay_us (40);

}

//simple procedure for temperature measure. single shot acquisistion

//This function will collect the temperature data and make the average

int temp_measure(){

char t;

int HVAL,LVAL, prova, i;

double temp;

long int sum;

sum=0;

for(i=0;i<N;i++) { // N is declared in the beginning of the file to easy reconfiguration

ADMUX = 0xc0;

ADCSRA =0b10000000;//BIT 3 INTERRUPT DISABLE

start_conv();

t=0;

while (t==0) {t = (ADCSRA & 0x10);};

LVAL = ADCL;

HVAL = ADCH & 0x03; //only for security (not needed)

LVAL = (HVAL*256)+LVAL; //HVAL is shifted 8 bits to get the total value of 10 bits.

temp = LVAL*(2.56/(1024))*1000; // Vref=2,56V , 2^10 bits , 1000=100(10mV per degree)*10(one decimal digit)

sum += temp; //average

_delay_us(311);

};

prova = sum/N;

// prova contain the value of temperature that will be show in the LCD

// the temp value is obtained by a mean of N sample of the sensor

// insert here any data elaboration of this value before showing

write_int_LCD(prova);

return prova;

}

//configuration of the interruption (for resetting)

void set_interrupt(){

char x; //x is a mask

x = 0x03;

MCUCR |= x; //int0 generates intererrupt on rising edge

x=0x40;

GICR |= x; //interrupt int0 enable

}

void enable_interrupt()

{

char x; //x is a mask

x = 0x80;

x= ~x;

GIFR &= x;

x = 0x80;

SREG |= x;

}

void disable_interrupt()

{

char x; //x is a mask

x = 0x80;

x= ~x;

SREG &= x;

}

//Routine of the interruption which changes the flag of resetting

SIGNAL (SIG_INTERRUPT0){

EXIT = 1;

}

//Main calculation of the pulse measurement

void pulse_measure_1(){

char t,above,b;

int HVAL,LVAL, max,min;

long int i;

long int j;

int time;

double freq;

double sum;

int k=0;

int thres,thres2;

ADMUX = 0b01000001; //channel1 selected, Aref

ADCSRA =0b10000000; //enable ADC

TCCR1B=0; //timer off

TCNT1 =0; // Reset timer value

start_conv();

t=0;

while (t==0) {t = (ADCSRA & 0x10);}; //check if sample is ready

LVAL = ADCL;

HVAL = ADCH & 0x03;

LVAL = (HVAL*256)+LVAL;

max = LVAL;

min = LVAL;

//We check the maximun and minimum during a little bit more than a period

for (i=0;i<MAX_INIT;i++)

{

start_conv();

t=0;

while (t==0) {t = (ADCSRA & 0x10);}; //check if sample is ready

LVAL = ADCL;

HVAL = ADCH & 0x03;

LVAL = (HVAL*256)+LVAL;

if(LVAL<min) min= LVAL;

if (LVAL>max) max=LVAL;

}

//calculation of the thresholds with those previous values

thres = min + ((max-min)*perc);

thres2 = min + ((max-min)*perc2);

//code necessary to enter correctly in the correct case of above (1 or 0)

above=2;

while(above!=0){

start_conv();

t=0;

while (t==0) {t = (ADCSRA & 0x10);}; //check if sample is ready

LVAL = ADCL;

HVAL = ADCH & 0x03;

LVAL = (HVAL*256)+LVAL;

// We are above or below the threshold?

if (LVAL>thres) above=1;

if (LVAL<thres2) above=0;

}

sum=0;

while(1){

j=0;

while(j<N_average){

if(MODE==1){

if((UCSRA & (1 << RXC)) != 0) { //if something received send the data

b=UDR;

send_int(freq_prev, 2); }

}

// Check the interrupt flag and jump outside the function if it's necessary

if (EXIT==1) {

goto RESET;}

start_conv();

t=0;

while (t==0) {t = (ADCSRA & 0x10);}; //check if sample is ready

LVAL = ADCL;

LVAL = (ADCH*256)+LVAL;

//structure of state diagram distinguish the above and below case

switch(above)

{

case 0: {

if (LVAL>thres) {

// timer() capability start;

TCCR1B=0; //timer off

time = TCNT1; //collect the value of the timer

TCNT1 =0; //reset the timer

TCCR1B |= ((1 << CS10) | (1 << CS12)); //timer on

if (time!=0) {

if(((UCSRA & (1 << RXC)) != 0)) { //if something received send the data

send_int(freq, '2'); }

freq = (4915200)/time; //4915200=8MHz (ferquency)*60(minute)*10(decimal)

sum += freq,

j++;

}

// timer() capability finish;

above=1;

}

break;

}

case 1: {

if (LVAL<thres2) { above=0;

}

}

}

}

next_line_LCD();

set_write_DR();

freq=sum/N_average;

if ((freq<500)|(freq>2000)) write_error_screen(); //Range of correct pulse between 50 and 200 ppm

else {write_int_LCD(freq);

freq_prev=freq;

}

sum=0;

if (k<N_reset) k++;

else {

k=0;

goto RESET;}

} //close while(1)

RESET:

TCCR1B=0; //timer off

TCNT1 =0; // Reset timer value

sum=0;

} //close function

void write_initial_screen_0(){

set_write_IR(); //entry mode of this text

write_data_LCD(0x06);

disable();

enable();

_delay_us(40);

set_write_DR(); // Show in the Screen PC Connected Press one for yes and Two for no

write_char('P');

write_char('C');

write_char('-');

write_char('C');

write_char('o');

write_char('n');

write_char('n');

write_char('e');

write_char('c');

write_char('t');

write_char('e');

write_char('d');

write_char('?');

next_line_LCD();

set_write_DR();

write_char('1');

write_char('Y');

write_char('e');

write_char('s');

write_char('-');

write_char('-');

write_char('-');

write_char('-');

write_char('2');

write_char('N');

write_char('o');

}

void main(void)

{

int a,b, measure;

b=0;

set_pin();

initial_LCD();

START: //starting point after reset

{EXIT=0;

MODE=0; //MODE=1 if we want to connect to PC

freq_prev=0;

disable_interrupt();

set_interrupt();

clear_LCD();

write_initial_screen_0();

MODE=buttom(); //choose if the PC is connected

if (MODE==1){

enable_interrupt();

clear_LCD();

set_write_IR(); //entry mode of this text

write_data_LCD(0x06);

disable();

enable();

_delay_us(40);

set_write_DR();

write_char('W');

write_char('a');

write_char('i');

write_char('t');

write_char('i');

write_char('n');

write_char('g');

write_char('-');

write_char('P');

write_char('C');

//enable serial communication and setting parameters

UCSRB |= (1 << RXEN) | (1 << TXEN);

UCSRC |= (1 << URSEL) | (1 << UCSZ0) | (1 << UCSZ1);

UBRRH = 0x00;;

UBRRL = 0x33; //=51 (9600bps at 8MHz) look table on datasheet

_delay_ms(1000);

//receive 1 from PC to start the communication

do{

while((UCSRA & (1 << RXC)) == 0) {

enable(); //is for the RESET

if (EXIT==1) {goto START;}};

b=UDR;

write_char(b);

//until a 1 is received indicating the PC is ready the program cannot go on

}while(b!='1');

b=0;

_delay_us(100);

//send a byte to the PC

while ((UCSRA & (1 << UDRE)) == 0) {}; //do nothing until buffer is empty

UDR = 0x33;

clear_LCD();

set_write_IR(); //entry mode of this text

write_data_LCD(0x06);

disable();

enable();

_delay_us(40);

set_write_DR();

write_char('P');

write_char('C');

write_char('-');

write_char('M');

write_char('o');

write_char('d');

write_char('e');

write_char('-');

write_char('O');

write_char('N');

_delay_ms(1000); //to have enough time to visualize the written before

}

clear_LCD();

_delay_ms(1000);

write_initial_screen();

a = buttom(); //from this point we wait for the preassure of the button

enable_interrupt();

switch (a) { //type of measurament

case 1:

_delay_ms(500);

clear_LCD();

write_temp_screen();

//the measurement of the temperature is continously running

while(1){

if (EXIT==1) { //exit point for resetting the device

goto START;}

next_line_LCD();

set_write_DR();

measure = temp_measure(); //temperature is calculated and displayed

if(MODE==1){ //if PC is connected

//if something is received from the PC the device send the temp data back

if((UCSRA & (1 << RXC)) != 0) {

b=UDR;

send_int(measure, 1); } //the 1 indicates temperature measure

_delay_ms(1000);

}

_delay_ms(400);

}

break;

case 2: clear_LCD();

write_pulse_screen();

//pulse measurement is continuosly running

while(1){

if (EXIT==1) {

goto START; }

pulse_measure_1();

}

break;

default: write_char('X'); //only for debugging

}

}

}