[arduino code examples for T16M]-01 Turn ON/OFF OUTPUT by 9555 chip

Code:
/*

 * Made by KinCony IoT: https://www.kincony.com

 *

 * This program controls a 16-channel relay board via an XL9555

 * I/O expander using the PCA95x5 library.

 *

 * It sequentially turns ON all 16 relays, then sequentially

 * turns them OFF, repeating continuously.

 *

 * Pin Definitions:

 * - SDA: GPIO 11

 * - SCL: GPIO 12

 *

 * I2C Address:

 * - XL9555: 0x25

 *

 * Relay Logic:

 * - LOW  = ON

 * - HIGH = OFF

 *

 * Switching Interval:

 * - 200 milliseconds

 */



#include <Wire.h>

#include <PCA95x5.h>



#define I2C_SDA_PIN  11

#define I2C_SCL_PIN  12

#define I2C_ADDRESS  0x25

#define DELAY_TIME   200

#define RELAY_COUNT  16



// Use the PCA9555 driver for the XL9555 I/O expander.

PCA9555 relayIO;



void setup() {

  // Initialize serial communication.

  Serial.begin(115200);



  // Initialize I2C: SDA = GPIO11, SCL = GPIO12, clock = 100 kHz.

  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN, 100000);



  Serial.println("XL9555 Relay Control: Starting...");



  // Attach the XL9555 to the I2C bus.

  relayIO.attach(Wire, I2C_ADDRESS);



  // Disable input polarity inversion.

  relayIO.polarity(PCA95x5::Polarity::ORIGINAL_ALL);



  // Preload all output latches HIGH before enabling outputs.

  // HIGH keeps the active-low relays OFF.

  relayIO.write(PCA95x5::Level::H_ALL);



  // Configure all 16 ports as outputs.

  relayIO.direction(PCA95x5::Direction::OUT_ALL);



  delay(50);



  Serial.println("All relays initialized to OFF.");

}



void loop() {

  // Sequentially turn ON relays 1-16.

  for (int i = 0; i < RELAY_COUNT; i++) {

    relayIO.write(

      (PCA95x5::Port::Port)i,

      PCA95x5::Level::L

    );



    Serial.print("Relay ");

    Serial.print(i + 1);

    Serial.println(" ON");



    delay(DELAY_TIME);

  }



  // Sequentially turn OFF relays 1-16.

  for (int i = 0; i < RELAY_COUNT; i++) {

    relayIO.write(

      (PCA95x5::Port::Port)i,

      PCA95x5::Level::H

    );



    Serial.print("Relay ");

    Serial.print(i + 1);

    Serial.println(" OFF");



    delay(DELAY_TIME);

  }

}