// Rushan Perera
// 74HC595 Shift Register to drive 7 Segments and Digit control
// 14.03.2025
// Version 1.50
//-------------------------------------------------------------- 1584 bytes /121 bytes [Flash-1.54KB /RAM-0.12KB]
#define DATA_PIN 8            // Data out pin
#define CLOCKPIN 7            // Clock out pin
#define LATCHPIN 4            // Latch pin
#define TIME     200          // For Loop delay Time

bool DPT = 0;                 // For decimal point toggle
byte del_count;               // Delay count for decimal point blink (keep value between 05-10) 

void setup() {
  pinMode(DATA_PIN,1);        // Set as output
  pinMode(CLOCKPIN,1);        // Set as output
  pinMode(LATCHPIN,1);        // Set as output
}

void loop() {
  int i;
                              // Shift_V2_Segment(Value,Segment,Decimal Point On/Off);  (Shift Value To Segment)
  for(i = 0; i < TIME; i++){                            
    Shift_V2_Segment(1,1,0);  // Show value 1 in segment 1
    Shift_V2_Segment(2,2,0);  // Show value 2 in segment 2 
    Shift_V2_Segment(3,3,0);  // Show value 3 in segment 3
    Shift_V2_Segment(4,4,2);  // Show value 4 in segment 4 
    delay(1);
  }
  for(i = 0; i < TIME; i++){   
    Shift_V2_Segment(5,1,0);    // Show value 5 in segment 5
    Shift_V2_Segment(6,2,1);    // Show value 6 in segment 6 with decimal point
    Shift_V2_Segment(7,3,0);    // Show value 7 in segment 7
    Shift_V2_Segment(8,4,0);    // Show value 8 in segment 8
    delay(1);
  } 
  for(i = 0; i < TIME; i++){  
    Shift_V2_Segment(9,1,0);    // Show value 9 in segment 1
    Shift_V2_Segment(0,2,0);    // Show value 0 in segment 2 
    Shift_V2_Segment(10,3,2);   // Show blank in segment 3 and blink its decimal point
    delay(1);
  }       
}

//-------------------------------------------------------------- Sub Functions

void Shift_V2_Segment(byte number, byte digit, byte dp){  
//-------------------------------------------------- Put Value to LEDs
 
char Segment[11][8] = {       // MSB 1st 0->>7
  {0,0,1,1,1,1,1,1},  //0
  {0,0,0,0,0,1,1,0},  //1
  {0,1,0,1,1,0,1,1},  //2
  {0,1,0,0,1,1,1,1},  //3
  {0,1,1,0,0,1,1,0},  //4
  {0,1,1,0,1,1,0,1},  //5
  {0,1,1,1,1,1,0,1},  //6
  {0,0,0,0,0,1,1,1},  //7
  {0,1,1,1,1,1,1,1},  //8
  {0,1,1,0,1,1,1,1},  //9
  {0,0,0,0,0,0,0,0},  // Blank -> Number 10 shows blank 
  };

  for (byte i = 0; i < 8; i++){  
   digitalWrite(DATA_PIN,Segment[number][i]);
   if (dp==1 && i==0){digitalWrite(DATA_PIN,1);}   // Turn ON decimal point 
   else if (dp==2 && i==0){                         
    del_count++;
    if (del_count == 8){
      DPT = !DPT, digitalWrite(DATA_PIN,DPT), del_count = 0;  // Toggle the decimal point
    }
   }  
   Clock();
  } 
//-------------------------------------------------- Select Segment
  
char Digits[4][8] = {
  {0,0,0,0,1,1,1,0},  // Segment 1
  {0,0,0,0,1,1,0,1},  // Segment 2
  {0,0,0,0,1,0,1,1},  // Segment 3
  {0,0,0,0,0,1,1,1},  // Segment 4
  };
  
  for (byte j = 0; j < 8; j++){  
   digitalWrite(DATA_PIN,Digits[digit-1][j]);
   Clock();
  }
   Latch(); 

   delay(5);
//-------------------------------------------------- Segment Off

  for (byte i = 0; i < 8; i++){  
   digitalWrite(DATA_PIN,0);  
   Clock();
  } 
  
  for (byte i = 0; i < 8; i++){  
   digitalWrite(DATA_PIN,1);
   Clock();
  }
   Latch();      
} 

//------------------------------------------------------------------ Clock Pulse

void Clock(){
  delayMicroseconds(100);
  digitalWrite(CLOCKPIN,1),  delayMicroseconds(50), digitalWrite(CLOCKPIN,0);  
}
//------------------------------------------------------------------ Latch Pulse

void Latch(){
  digitalWrite(LATCHPIN,1), delayMicroseconds(50), digitalWrite(LATCHPIN,0), delayMicroseconds(50);   
}