 #define DIGITS 4
 
 // define the bitmasks for characters 0-9
-byte LCD_DIGIT_MASK[] = {
+byte LED_DIGIT_MASK[] = {
   0b00111111,
   0b00000110,
   0b01011011,

  0b01111111,
  0b01101111
};

volatile int number_for_display = 0;   // the number we'll display on the LED unit
volatile byte current_digit = 0;       // 0-3 left to right

void setup() {
  Serial.begin(9600); 
  pinMode(ST_CP_LATCH_PIN, OUTPUT);
  pinMode(SH_CP_CLOCK_PIN, OUTPUT);
  pinMode(DS_DATA_PIN, OUTPUT);

  byte digit_value = (number_for_display / digit_scale) % 10;

  // push the digit to the LED display
  pushSegmentRegister(LED_DIGIT_MASK[digit_value]);
  digitalWrite(DIGIT_BASE_PIN + current_digit, HIGH);
}

