Test_I2C_ESP866_PCF8574

  #include <Wire.h>
  //---------------------------
  void setup()
  {
    Wire.begin(2,0);  // ESP8266
    //Wire.begin();  // Arduino
  }
  //---------------------------
  void loop()
  {                                                 // Se PCF8574A mude 38 para 20
    Wire.beginTransmission(0x38);                   // Begin the transmission to PCF8574
    Wire.write(0);                                  // Zera as portas
    Wire.endTransmission();                         // End the Transmission
    delay(1000);                                    // Delay 1 seg
    Wire.beginTransmission(0x38);                   // Begin the transmission to PCF8574
    Wire.write(0xFF);                               // Liga todas portas
    Wire.endTransmission();                         // End the Transmission
    delay(1000);                                    // Delay 1 seg
  }