/*
 * PCF8575 GPIO Port Expand
 * Inverted led test: all led is connected with anodo to the IC
 *
 * PCF8575    ----- WeMos
 * A0         ----- GRD
 * A1         ----- GRD
 * A2         ----- GRD
 * VSS        ----- GRD
 * VDD        ----- 5V/3.3V
 * SDA        ----- GPIO_4(PullUp)
 * SCL        ----- GPIO_5(PullUp)
 *
 * P0     ----------------- LED0
 * P1     ----------------- LED1
 * P2     ----------------- LED2
 * P3     ----------------- LED3
 * P4     ----------------- LED4
 * P5     ----------------- LED5
 * P6     ----------------- LED6
 * P7     ----------------- LED7
 * P8     ----------------- LED8
 * P9     ----------------- LED9
 * P10     ----------------- LED10
 * P11     ----------------- LED11
 * P12     ----------------- LED12
 * P13     ----------------- LED13
 * P14     ----------------- LED14
 * P15     ----------------- LED15
 *
 */

#include "Arduino.h"
#include "PCF8575.h"  // https://github.com/xreef/PCF8575_library

// Set i2c address
PCF8575 pcf8575(0x20);

void setup()
{
  Serial.begin(9600);

  // Set pinMode to OUTPUT
  for(int i=0;i<16;i++) {
    pcf8575.pinMode(i, OUTPUT);
  }
  for(int i=0;i<16;i++) {
	  pcf8575.digitalWrite(i, HIGH);
  }

  pcf8575.begin();
}

void loop()
{
  static int pin = 0;
  pcf8575.digitalWrite(pin, LOW);
  delay(1000);
  pcf8575.digitalWrite(pin, HIGH);
  delay(1000);
  pin++;
  if (pin > 15) pin = 0;
}