const char digitPatterns[10] = {
  0b00111111, 
  0b00000110, 
  0b01011011, 
  0b01001111, 
  0b01100110, 
  0b01101101, 
  0b01111101, 
  0b00000111, 
  0b01111111, 
  0b01101111  
};

void setup() {
  volatile char *direction_f = (char*)0x30;
  volatile char *output_f = (char*)0x31;
  volatile char *direction_k = (char*)0x107;
  volatile char *input_k = (char*)0x106;

 
  *direction_f = 0xff;  
  *direction_k = 0x00;  

  int count = 0;  
  *output_f = digitPatterns[count];  

  while (1) {
    
    volatile int trace = *input_k;

    
    if (trace & 0x01) {
      int display = 1;  
      while (display) {
        for (int j = 0; j <= 9; j++) {
          if (trace & 0x02) {  
            *output_f = 0x00;  
            display = 0;  
            break;  
          }
          *output_f = digitPatterns[j];
          delayLoop();
        }
       
      }
    } else {
      *output_f = digitPatterns[0];  
  }
}
}
void delayLoop() {
  for (volatile long long j = 0; j < 100000; j++);
}