#include <Arduino.h>
#include <SPI.h>

#define LATCH_PIN 5   // STCP (Latch clock) pin on 74HC595
#define DATA_PIN 23   // DS (MOSI) pin on 74HC595 (MOSI)
#define CLOCK_PIN 18  // SHCP (SCK) pin on 74HC595 (SCK)


void updateShiftRegister(byte data);

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  pinMode(LATCH_PIN, OUTPUT);

  // Initialize SPI with the correct pins
  SPI.begin(CLOCK_PIN, -1, DATA_PIN, -1);  // Initialize SPI with SCK and MOSI

  // Turn all LEDs off initially
  updateShiftRegister(0x00);  // All LEDs OFF
}

byte data1 = 0xC3;
byte data2 = 0x3C;
byte data3 = 0xAA;

void loop() {
  // // Pattern 1: Turn LEDs on one by one
  // byte data = 0x00;  // All LEDs initially OFF
  // for (int i = 0; i < 8; i++) {
  //   data |= 1 << i;  // Turn on one LED at a time
  //   updateShiftRegister(data);
  //   delay(200);  // 200ms delay between LEDs
  // }
  // delay(1000);

  // // Pattern 2: Turn LEDs off one by one
  // byte currentState = 0xFF;  // All LEDs initially ON
  // for (int i = 0; i < 8; i++) {
  //   currentState &= ~(1 << i);  // Turn off one LED at a time
  //   updateShiftRegister(currentState);
  //   delay(200);  // 200ms delay between LEDs
  // }
  // delay(1000);

  // Pattern 3: 50% ON, 50% OFF (First Half ON, Second Half OFF)
  // Send the byte of data via SPI
  SPI.beginTransaction(SPISettings(10000000, MSBFIRST, SPI_MODE0));  // Configure SPI speed
  SPI.transfer(data1);
  // SPI.transfer(data2);
  // SPI.transfer(data3);
  SPI.endTransaction();

  // Latch high to set the output of the shift register
  digitalWrite(LATCH_PIN, LOW);
  digitalWrite(LATCH_PIN, HIGH);
  data1 ^= 0xFF;
  data2 ^= 0xFF;
  data3 ^= 0xFF;
  delay(500);  // 500ms delay
}

// Function to update the 74HC595 shift register using SPI
void updateShiftRegister(byte data) {
  // Latch low to begin transmitting data
  digitalWrite(LATCH_PIN, LOW);

  // Send the byte of data via SPI
  SPI.beginTransaction(SPISettings(10000000, MSBFIRST, SPI_MODE0));  // Configure SPI speed
  SPI.transfer(data);
  SPI.endTransaction();

  // Latch high to set the output of the shift register
  digitalWrite(LATCH_PIN, HIGH);
}