sample program

DigiKeyboard.cpp

#include "DigiKeyboard.h"
#include <avr/pgmspace.h>

const uint8_t RTC[] PROGMEM = "Recruit Technologies Co., Ltd. ";
const uint8_t ATL[] PROGMEM = "Advanced Technology Lab. ";

#define KEY_ENTER 0x28
#define KEY_CAPSLOCK 0x39
// https://gist.github.com/MightyPork/6da26e382a7ad91b5496ee55fdc73db2

void println(const uint8_t *s) {
  uint8_t a, i;
  i = 0;
  do {
    a = pgm_read_byte(s + i++);
    DigiKeyboard.write(a);
  } while (a);
  DigiKeyboard.sendKeyStroke(KEY_ENTER);
}

void setup() {
  DigiKeyboard.sendKeyStroke(0);
  pinMode(1, OUTPUT);
}

void loop() {
  println(RTC);
  println(ATL);
  delay(500);
  DigiKeyboard.sendKeyStroke(KEY_CAPSLOCK, MOD_SHIFT_LEFT);
}