full_adder_project_paul_youtube.ino

//Follow  Project Paul on YouTube: https://www.youtube.com/c/frugalteq

#include <LiquidCrystal_I2C.h>
#include <Wire.h>

int carry = 10;
int sum2 = 9;
int sum1 = 8;
int sum2val = 0;
int sum1val = 0;
int carval = 0;
int pins = 0;



LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);  // Set the LCD I2C address

void setup() 
{
  Serial.begin(9600);
  // set up the LCD's number of columns and rows: 
  lcd.begin(16,2);
  pinMode(carry, INPUT);
  pinMode(sum1, INPUT);
  pinMode(sum2, INPUT);

}

void loop() 
{
  sum1val = digitalRead(sum1);
  sum2val = digitalRead(sum2);
  carval = digitalRead(carry);
  
  pins = PINB & 0x7; //reads port registers 8 - 13 INPUT state

  lcd.setCursor(0, 0);

//SWITCH/CASE

  switch (pins) {

   case 0:
   sum1val = 0;
   sum2val = 0;
   carval = 0;
   lcd.print("0");
   break;
   
   case 1:
   sum1val = 1;
   sum2val = 0;
   carval = 0;
   lcd.print("1");
   break;
   
   case 2:
   sum1val = 0;
   sum2val = 1;
   carval = 0;
   lcd.print("2");
   break;
   
   case 3: 
   sum1val = 1;
   sum2val = 1;
   carval = 0;
   lcd.print("3");
   break;
   
   case 4: 
   sum1val = 0;
   sum2val = 0;
   carval = 1;
   lcd.print("4");
   break;
   
   case 5: 
   sum1val = 1;
   sum2val = 0;
   carval = 1;
   lcd.print("5");
   break;
   
   case 6: 
   sum1val = 0;
   sum2val = 1;
   carval = 1;
   lcd.print("6");
   break;
   
   }

//END SWITCH 

//Can use if/else instead of switch/case
/*
   if ((sum1val == 0) && (sum2val == 0) && (carval == 0))
   {
   lcd.print("0");
   }
   else if ((sum1val == 1) && (sum2val == 0) && (carval == 0))  
   {
   lcd.print("1");
   }
   else if ((sum1val == 0) && (sum2val == 1) && (carval == 0))
   {
   lcd.print("2");
   }
   else if ((sum1val == 1) && (sum2val == 1) && (carval == 0))
   {
   lcd.print("3");
   }
   else if ((sum1val == 0) && (sum2val == 0) && (carval == 1))
   {
   lcd.print("4");
   }
   else if ((sum1val == 1) && (sum2val == 0) && (carval == 1))
   {
   lcd.print("5");
   }
   else if ((sum1val == 0) && (sum2val == 1) && (carval == 1))
   {
   lcd.print("6");
   }
   */
   
  delay(100);
  lcd.clear();
}