#define DP_0 2
#define DP_1 3
#define DP_2 4
#define DP_3 5
#define AR 6
#define CR 7

#define STANDBY 0
#define READ 1
#define WRITE 2


char count = 0;
char delayAmount = 100;
char textToSent[]  = "Hallo vom Arduino Nano!";

char mode;

char getScreenCode(char c) {
  if (c >= 32 && c <= 63) {
    return c;
  } else if (c == 64) {
    return 0;
  } else if (c >= 65 && c <= 90) {
    return c;
  } else if (c == 91 || c == 93) {
    return c - 64;
  } else if (c == 95) {
    return 111;
  } else if (c >= 97 && c <= 122) {
    return c - 96;
  } else if (c == 124) {
    return 93;
  } else {
    return 63;
  }
}

void initMode(char mode) {

  switch (mode) {
    case WRITE:
      pinMode(DP_0, OUTPUT);
      pinMode(DP_1, OUTPUT);
      pinMode(DP_2, OUTPUT);
      pinMode(DP_3, OUTPUT);
      break;
    case STANDBY:
    default:
      pinMode(DP_0, INPUT);
      pinMode(DP_1, INPUT);
      pinMode(DP_2, INPUT);
      pinMode(DP_3, INPUT);
  }

  pinMode(AR, OUTPUT);
  pinMode(CR, INPUT);

  digitalWrite(DP_0, LOW);
  digitalWrite(DP_1, LOW);
  digitalWrite(DP_2, LOW);
  digitalWrite(DP_3, LOW);
  digitalWrite(AR, LOW);
  digitalWrite(CR, LOW);

}

void setup() {
  delay(2000);
  mode = STANDBY;
  initMode(mode);

  Serial.begin(9600);
  
}

void send4Bit(char c) {

  for (char i = 3; i >= 0; i--) {
    char d = c >> i & 1;
    Serial.print(d, DEC);
  }

  for (char i = 0; i < 4; i++) {
    char d = c >> i & 1;
    digitalWrite(i+2, d);
  }
  Serial.print(" ");
  digitalWrite(AR, HIGH);

  while (digitalRead(CR) == LOW) {}

  while (digitalRead(CR) == HIGH) {}
  digitalWrite(AR, LOW);

  //delay(500);
}

void sendByte(char a, char byte) {
  char upper = byte >> 4;
  char lower = byte & 0b00001111;


  Serial.print(a);
  Serial.print(" ");
  Serial.print(a, DEC);
  Serial.print(" ");
  Serial.print(byte, DEC);
  Serial.print(" ");
  send4Bit(upper);
  send4Bit(lower);
}

void startWrite() {
  Serial.print("start\n");
  mode = WRITE;
  initMode(mode);
  digitalWrite(AR, LOW);

  int i = 0;
  char c, sc;
  do {
    c = textToSent[i];
    sc = getScreenCode(c);
    i++;
    sendByte(c, sc);
    //Serial.print(c, DEC);
  } while (c != 0);

  Serial.print("\n");

  for (char i = 2; i < 8; i++) {
    digitalWrite(i, LOW);
  }

  mode = STANDBY;
}

void loop() {

  if (mode == WRITE) {

  } else if (mode == READ) {
    
  } else {
    startWrite();    
  }

  Serial.print("\nAAAAAAAA\n");

  delay(20000);

}