Hex digits through a 74HC595 (pins 11, 8 and 12), on an Arduino Uno

// A 74HC595 drives one seven-segment digit: 0 to 9, then A to F.
//
//   74HC595 DS -> pin 11    SH_CP -> pin 8    ST_CP -> pin 12
//   74HC595 VCC and MR -> 5V      GND and OE -> GND
//   Q0 to Q6 -> segments a to g, Q7 -> the dot
//   the display's common cathode -> 220 ohm -> GND
//
// shiftOut() sends a byte one bit at a time on DS, with a pulse on SH_CP for
// each bit; a pulse on ST_CP then copies all eight to the outputs at once.
// With MSBFIRST and segment a in the lowest bit, bit 0 ends up on Q0.

const int DS = 11;
const int SHCP = 8;
const int STCP = 12;

//                      gfedcba
const byte HEX_DIGITS[16] = {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07,
                             0x7F, 0x6F, 0x77, 0x7C, 0x39, 0x5E, 0x79, 0x71};
const char SYMBOLS[] = "0123456789ABCDEF";

void setup() {
  pinMode(DS, OUTPUT);
  pinMode(SHCP, OUTPUT);
  pinMode(STCP, OUTPUT);
  Serial.begin(9600);
  Serial.println("Mokxi Uno: 74HC595 on pins 11, 8 and 12");
}

void loop() {
  for (int i = 0; i < 16; i++) {
    digitalWrite(STCP, LOW);
    shiftOut(DS, SHCP, MSBFIRST, HEX_DIGITS[i]);
    digitalWrite(STCP, HIGH);
    Serial.println(SYMBOLS[i]);
    delay(1000);
  }
}