ArduinoShiftRegisters.ino

// ArduinoShiftRegisters.ino
//
// for use at http://falstad.com/circuit/avr8js/
//
//
#define  DUR       50LU
#define  dataPin   8
#define  clockPin  9
#define  ActiveHi  true

int pass;

inline void clk() {
  digitalWrite(clockPin, ActiveHi ? HIGH : LOW);
  delayMicroseconds(DUR);
  digitalWrite(clockPin, (!ActiveHi) ? HIGH : LOW);
  delayMicroseconds(DUR);
}

inline void shift_bit(bool const val) {
  digitalWrite(dataPin, val ? HIGH : LOW);
  delayMicroseconds(DUR);
 clk();
}

inline void shift_byte(uint8_t const val) {
  for (register int8_t i=0; i < 8; i++) {
    uint8_t bit = (val >> i) & 0x01;
    shift_bit(bit);
  }
}

inline void clear() {
  Serial.print("clearing..");
  for (int i=0; i < 7; i++) {
    shift_byte(0);
  }
  Serial.println("finished");
}

void setup() {
  Serial.begin(115200);

  // add external voltage (Javascript) with name "pin n" to access output pins
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);

  digitalWrite(clockPin, (!ActiveHi) ? HIGH : LOW);
  delayMicroseconds(DUR);

  clear();
}

void loop() {
  Serial.print("Pass ");
  Serial.println(++pass);

  shift_byte(0x3A);   // 'o'
  shift_byte(0x2A);   // 'n'
  shift_byte(0x20);   // 'i'
  shift_byte(0x38);   // 'u'
  shift_byte(0x7A);   // 'd'
  shift_byte(0x0A);   // 'r'
  shift_byte(0xEF);   // 'A'

  delay(10);
  clear();
  // delay(50);
}