#include <PCF8574.h>

PCF8574 pcf20(0x27);

void setup() {
  Serial.begin(115200);
  delay(500);
//  Serial.print("PCF8574_LIB_VERSION:\t");
//  Serial.println(PCF8574_LIB_VERSION);

  if (!pcf20.begin()) {
    Serial.println("Chip not responding.");
  }

  if (!pcf20.isConnected()) {
    Serial.println("could not initialize... => not connected");
    while (1);
  }

  for (uint8_t i = 0; i < 3; i++) {
    pcf20.write8(255);
    delay(100);
    pcf20.write8(0);
    delay(200);
  }
  delay(800);
/*
    pcf20.write(0, 1);
      delay(300);
    pcf20.write(2, 1);
      delay(300);
    pcf20.write(7, 1);
    delay(2000);
    pcf20.write(0, 0);
      delay(300);
    pcf20.write(2, 0);
      delay(300);
    pcf20.write(7, 0);
    delay(2000);
*/
  pcf20.write(0, 1);
  delay(125);
}

void loop() {

  for (int i = 0; i < 7; i++) {
    pcf20.shiftLeft();
    delay(125);
  }

  for (int i = 0; i < 7; i++) {
    pcf20.shiftRight();
    delay(125);
  }
  delay(1);
}