input_pcf_analog_isolate

#include "PCF8574.h"
PCF8574 pcf8574(0x20);
byte IN1 = P3;
byte IN2 = P2;
byte IN3 = P1;
byte IN4 = P0;
byte LED = 15;
bool stateLed = 0;
unsigned long cur_time, old_time;
void setup() {
  // put your setup code here, to run once:
  delay(100);
  Serial.begin(115200);
  pinMode(LED, OUTPUT);
  pcf8574.pinMode(IN1, INPUT);
  pcf8574.pinMode(IN2, INPUT);
  pcf8574.pinMode(IN3, INPUT);
  pcf8574.pinMode(IN4, INPUT);
  Serial.print("Init pcf8574...");
  if (pcf8574.begin()) {
    Serial.println("OK");
  } else {
    Serial.println("KO");
  }
  delay(100);
}

void loop() {
  // put your main code here, to run repeatedly:
  cur_time = millis();
  if(cur_time - old_time >= 3000){
    stateLed = !stateLed;
    digitalWrite(LED,stateLed);
    Serial.print(pcf8574.digitalRead(IN1));
    Serial.print(pcf8574.digitalRead(IN2));
    Serial.print(pcf8574.digitalRead(IN3));
    Serial.println(pcf8574.digitalRead(IN4));
    old_time = millis();
  }
}