// Two digit Seven Segment Countdown Clock
 
// Define the LED digit patters, from 0 - 9
// Note that these patterns are for common cathode displays
// For common anode displays, change the 1's to 0's and 0's to 1's
// 1 = LED on, 0 = LED off, in this order:
//               Arduino ones pin: 0,1,2,3,4,5,6
//              Arduino tens pin: 7,8,9,10,11,12,13             
byte seven_seg_digits[10][7] = { { 1,1,1,1,1,1,0 },  // = 0
                                 { 0,1,1,0,0,0,0 },  // = 1
                                 { 1,1,0,1,1,0,1 },  // = 2
                                 { 1,1,1,1,0,0,1 },  // = 3
                                 { 0,1,1,0,0,1,1 },  // = 4
                                 { 1,0,1,1,0,1,1 },  // = 5
                                 { 1,0,1,1,1,1,1 },  // = 6
                                 { 1,1,1,0,0,0,0 },  // = 7
                                 { 1,1,1,1,1,1,1 },  // = 8
                                 { 1,1,1,1,0,1,1 }   // = 9
                                 };

byte circular_digits[6][7] = { { 1,0,0,0,0,0,0 },  // = 0
                                { 0,1,0,0,0,0,0 },  // = 1
                                { 0,0,1,0,0,0,0 },  // = 2
                                { 0,0,0,1,0,0,0 },  // = 3
                                { 0,0,0,0,1,0,0 },  // = 4
                                { 0,0,0,0,0,1,0 },  // = 5
                                };

void setup() {
  //set all pins to output mode
  pinMode(0, OUTPUT);
  pinMode(1, OUTPUT);  
  pinMode(2, OUTPUT);   
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(13, OUTPUT);
}

void writeDot(byte dot) {
  digitalWrite(9, dot);
}
    
void sevenSegWrite(byte digit, byte place) {
  byte pin;
  if (place == 1) {
  pin = 0;
  }
  else {
  pin = 7;
  }
  for (byte segCount = 0; segCount < 7; ++segCount) {
    digitalWrite(pin, seven_seg_digits[digit][segCount]);
    ++pin;
  }
}

void circularDigitWrite(byte digit, byte pin){
  for (byte segCount = 0; segCount < 7; ++segCount) {
    digitalWrite(pin, circular_digits[digit][segCount]);
    ++pin;
  }
}

void loop() {
  for (byte count = 60; count > 0; --count) {
   delay(991);
   sevenSegWrite((int)((count-1)/10), 10);
   sevenSegWrite(count-1-((int)((count-1)/10)*10), 1); 
  }
  for (byte count = 6; count > 0; --count) {
    delay(50);
    circularDigitWrite(count-1, 0);
    circularDigitWrite(count-1, 7);
   if (count <= 1) {
    count = 7;
   }
 }
}