// 74HC165 Pins
const int PL = 7;     // Parallel load pin (active LOW)
const int CP = 8;     // Clock pin
const int QH = 9;     // Serial out

// 74HC595 Pins
const int DS = 6;     // Serial in
const int SH_CP = 5;  // Shift register clock
const int ST_CP = 4;  // Storage register clock (latch)

const int numChips = 2;  // Number of 165s and 595s

void setup() {
  // Set up pins
  pinMode(PL, OUTPUT);
  pinMode(CP, OUTPUT);
  pinMode(QH, INPUT);

  pinMode(DS, OUTPUT);
  pinMode(SH_CP, OUTPUT);
  pinMode(ST_CP, OUTPUT);

  // Start serial communication
  Serial.begin(9600);
  Serial.println("System initialized.");
}

void loop() {
  byte inputBytes[numChips];

  // Load parallel inputs from 74HC165
  digitalWrite(PL, LOW);
  delayMicroseconds(5);
  digitalWrite(PL, HIGH);

  // Read bytes from 74HC165
Serial.print("Read from 74HC165: ");
for (int i = 0; i < numChips; i++) {
  inputBytes[i] = shiftIn(QH, CP, MSBFIRST);
  Serial.print("0b");
  for (int bit = 7; bit >= 0; bit--) {
    Serial.print((inputBytes[i] >> bit) & 1);
  }
  Serial.print(" ");
}
Serial.println();
  /*
  Serial.print("Read from 74HC165: ");
  for (int i = 0; i < numChips; i++) {
    inputBytes[i] = shiftIn(QH, CP, MSBFIRST);
    Serial.print("0b");
    Serial.print(inputBytes[i], BIN);
    Serial.print(" ");
  }
  Serial.println();*/

  // Send to 74HC595
  digitalWrite(ST_CP, LOW);
  Serial.print("Writing to 74HC595: ");
  for (int i = numChips - 1; i >= 0; i--) {
    shiftOut(DS, SH_CP, MSBFIRST, inputBytes[i]);
    Serial.print("0b");
    Serial.print(inputBytes[i], BIN);
    Serial.print(" ");
  }
  digitalWrite(ST_CP, HIGH);
  Serial.println();
  Serial.println("----");

  delay(1000); // Adjustable delay for debugging
}