[arduino code examples for B4]-02 Read digital input ports state

Code:
/*

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

 *

 * Description:

 * This Arduino program reads the state of a 16-channel PCF8574 I/O expander

 * and prints the state of all input pins to the Serial Monitor. The state of 

 * each pin is represented as a bit in a 8-bit value, where each bit corresponds 

 * to an input pin. The program prints the input state in binary format.

 *

 * Pin Definitions:

 * - SDA: GPIO 21

 * - SCL: GPIO 22

 * - PCF8575 I2C Address: 0x24

 */



#include "Arduino.h"

#include "PCF8574.h"



// Define I2C pins

#define I2C_SDA 8  // Define SDA pin

#define I2C_SCL 18  // Define SCL pin



// Set I2C address

PCF8574 pcf8574_IN1(0x24); // The I2C address of the PCF8575



void setup() {

    Serial.begin(115200);



    // Initialize I2C communication

    Wire.begin(I2C_SDA, I2C_SCL); // Initialize I2C with defined SDA and SCL pins



    pcf8574_IN1.pinMode(P0, INPUT);

    pcf8574_IN1.pinMode(P1, INPUT);

    pcf8574_IN1.pinMode(P2, INPUT);

    pcf8574_IN1.pinMode(P3, INPUT);



    pcf8574_IN1.begin(); // Initialize the PCF8575



    Serial.println("KinCony F4 4 channel input state 0:ON  1:OFF");

}



void loop() {

    uint16_t state = 0;



    // Read the state of each pin (assuming 16 pins)

    for (int pin = 0; pin < 4; pin++) {

        if (pcf8574_IN1.digitalRead(pin)) {

            state |= (1 << pin); // Set the bit for the active pin

        }

    }



    Serial.print("Input state: ");

    Serial.println(state, BIN); // Print the state of inputs in binary



    delay(500); // Delay 500ms

}