Using a geometric series to control many LEDs

Projects Programming
11

If you split the value in two bytes, you can assign the first byte directly to PORTD 0...7 and the second to PORTB 4-5:

void set_outputs (int value)
  {
  PORTD = value&255;
  PORTB &= ~((value>>8)<<4);
  PORTB |= (value>>8)<<4;
  }

Connect LEDs to B5, B4, D7, D6, D5, D4, D3, D2, D1, D0 (for 1024 conditions from 0 to 1023 you need only 10 outputs).