#include <Wire.h>  // Include the Wire library for I2C communication

#define PCA9555_ADDR 0x20  // I2C address of PCA9555

void setup() {
  Wire.begin();  // Initialize I2C communication
}

void loop() {
  // Example: Set all pins of PCA9555 as outputs
  Wire.beginTransmission(PCA9555_ADDR);
  Wire.write(0x06);  // Configuration register address
  Wire.write(0x00);  // Set all pins as outputs
  Wire.endTransmission();

  // Example: Set output states of PCA9555
  Wire.beginTransmission(PCA9555_ADDR);
  Wire.write(0x02);  // Output register address
  Wire.write(0xFF);  // Set all pins to high
  Wire.endTransmission();

  delay(1000);  // Wait for 1 second

  // Example: Turn off all outputs
  Wire.beginTransmission(PCA9555_ADDR);
  Wire.write(0x02);  // Output register address
  Wire.write(0x00);  // Set all pins to low
  Wire.endTransmission();

  delay(1000);  // Wait for 1 second
}