Tema sbmm

#include <LiquidCrystal.h>
#include<math.h>
const int rs = 8, en = 9, d4 = 10, d5 = 11, d6 = 12, d7 = 13;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

int  nrGrade;

void setup(){
  DDRC &= ~0x30;
  DDRD |= 0xFF;
  lcd.begin(16, 2);
  PORTD = 0x00;
  adc_init();

}
void Switch(int b){
   switch(b){
    case 0: PORTD = 0x7E; break;
    case 1: PORTD = 0x30; break;
    case 2: PORTD = 0x6D; break;
    case 3: PORTD = 0x79; break;
    case 4: PORTD = 0x33; break;
    case 5: PORTD = 0x5B; break;
    case 6: PORTD = 0x5F; break;
    case 7: PORTD = 0x70; break;
    case 8: PORTD = 0x7F; break;
    case 9: PORTD = 0x73; break;
  }
 delay(1000);
}

void AfisGrade(){
  PORTD = 0x63;
  delay(1000);
  PORTD = 0x4E;
  delay(1000);

}

void loop(){

  nrGrade =(int) (((unsigned long int)read_adc(5) * 5000 / 1023) - 500) / 10;
  lcd.clear();
  lcd.print(nrGrade);
   delay(1000);
  if(nrGrade < 0){
      PORTD = 0x01;
      delay(1000);
      nrGrade = - nrGrade;

    }

    if(nrGrade < 10) Switch(nrGrade);
    else if (nrGrade < 100){
     Switch(nrGrade / 10);
     Switch(nrGrade % 10);
    }
    else {
     Switch(nrGrade / 100);
     Switch(nrGrade / 10 % 10);
     Switch(nrGrade % 10);
    }

    AfisGrade();
    delay(1000);
    lcd.clear();
    lcd.setCursor(0,0);



}

void adc_init()//adc initialization
{
ADCSRA |= ((1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0));//set division factor between system clock frequency and the input clock to the ADC- 128
ADMUX |= (1 << REFS0);//AVcc with external capacitor at Aref pin
ADCSRA |= (1 << ADEN);//enable ADC
ADCSRA |= (1 << ADSC);//ADC start conversion
}
uint16_t read_adc(uint8_t channel)
{
ADMUX &= 0xF0;//set input AO to A5
ADMUX |= channel;//select chanel AO to A5
ADCSRA |= (1 << ADSC);//start conversion
while(ADCSRA & (1 << ADSC));//wait wile adc conversion are not updated
return ADCW;//read and return voltage
}