#define SHIFT_DATA 2
#define SHIFT_CLK 3
#define SHIFT_LATCH 4
#define EEPROM_D0 5
#define EEPROM_D7 12
#define EEPROM_WE 13

#define NONE 0
#define READ INPUT
#define WRITE OUTPUT

int mode = NONE;

void setup() {
  pinMode(SHIFT_DATA, OUTPUT);
  pinMode(SHIFT_CLK, OUTPUT);
  pinMode(SHIFT_LATCH, OUTPUT);
  pinMode(EEPROM_WE, OUTPUT);

  digitalWrite(SHIFT_DATA, LOW);
  digitalWrite(SHIFT_CLK, LOW);
  digitalWrite(SHIFT_LATCH, LOW);digitalWrite(EEPROM_WE, HIGH);


  writeEEPROM(0, 0);

  for (int i = 0; i < 2048; i++) {
    writeEEPROM(i, i);
    delay(50);
  }
}

void writeEEPROM(int address, int data) {
  for (int pin = EEPROM_D0; pin <= EEPROM_D7; pin++) {
    pinMode(pin, OUTPUT);
  }
  setAddress(address, false);
  for (int pin = EEPROM_D0; pin <= EEPROM_D7; pin++) {
    digitalWrite(pin, data & 0x01);
    data = data >> 1;
  }

  digitalWrite(EEPROM_WE, LOW);
  delayMicroseconds(1);
  digitalWrite(EEPROM_WE, HIGH);
}

byte readEEPROM(int address) {
  for (int pin = EEPROM_D0; pin <= EEPROM_D7; pin++) {
    pinMode(pin, INPUT);
  }
  setAddress(address, true);
  byte data = 0;
  for (int pin = EEPROM_D7; pin >= EEPROM_D0; pin--) {
    data = (data << 1) + digitalRead(pin);
  }
  return data;
}

void setAddress(int address, bool outputEnable) {
  shiftOut(SHIFT_DATA, SHIFT_CLK, MSBFIRST, (address >> 8) | (outputEnable ? 0x00 : 0x80));
  shiftOut(SHIFT_DATA, SHIFT_CLK, MSBFIRST, address);

  digitalWrite(SHIFT_LATCH, 0);
  digitalWrite(SHIFT_LATCH, 1);
  digitalWrite(SHIFT_LATCH, 0);
}

// the loop function runs over and over again forever
void loop() {
  for (int i = 0; i < 2048; i++) {
    readEEPROM(i);
    delay(50);
  }
}