#include <SoftwareSerial.h>

const int dataInPin = 4;
const int clockPin = 2;
const int latchPin = 3;
const int dataOutPin = 5;
int bit;
byte data = 0;

const int numBits = 8;
byte RAM[] = {0B00000001,0B00000010,0B00000100,0B00001000};

SoftwareSerial Serial(PB0, PB1);

void store(){
  digitalWrite(clockPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(clockPin, LOW);
  delayMicroseconds(10);
}

void shiftWrite(int desiredPin, boolean desiredState){
  bitWrite(data,desiredPin,desiredState);
  shiftOut(dataOutPin, clockPin, MSBFIRST, data);
  digitalWrite(latchPin, HIGH); 
  digitalWrite(latchPin, LOW); 
}

void setup() {
  Serial.begin(9600);
  pinMode(dataInPin, INPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
}

void loop() {
  digitalWrite(latchPin, LOW);
  digitalWrite(latchPin, HIGH);

  Serial.print("Bits: ");
  for (int i = 0; i < numBits; i++) {
    bit = digitalRead(dataInPin);
    if (bit == HIGH) {
      Serial.print("1");
    } else {
      Serial.print("0");
    }
    store();
  }

  Serial.println();
  delay(1000);
  if(bit == 00000001){ 
      int index = RAM[0]; 
      shiftWrite(index, 1);   
  }
  bit = 0;
}