   Wire.write(0x01);
   Wire.write(0x00);
   Wire.endTransmission();
-//  Wire.beginTransmission(0x20);
-//  //Write '1' to GPB0-GPB3
-//  Wire.write(0x13);
-//  Wire.write(0x0f);
-//  Wire.endTransmission();
 
   //select SDA0 / SCL0
   selectI2cChannels(I2C_CHANNEL_SDSC0);

  Wire.write(0x01);
  Wire.write(0xFE);
  Wire.endTransmission();
  Wire.beginTransmission(0x20);
  Wire.write(0x13);
  Wire.write(0x01);
  Wire.endTransmission();
}

void loop() {
  // put your main code here, to run repeatedly:
  selectI2cChannels(I2C_CHANNEL_SDSC3);
  Wire.beginTransmission(0x20);
  Wire.write(0x13);
  Wire.write(0x00);
  Wire.endTransmission();
  delay(100);
  
  selectI2cChannels(I2C_CHANNEL_SDSC0);
  Wire.beginTransmission(0x20);
  Wire.write(0x13);
  Wire.endTransmission();
  Wire.requestFrom(0x20, 1);
  result = Wire.read();
  if (result & 0x02) {
    Wire.beginTransmission(0x20);
    Wire.write(0x13);
    Wire.write(0x00);
    Wire.endTransmission();
  } else {
    Wire.beginTransmission(0x20);
    Wire.write(0x13);
    Wire.write(0x01);
    Wire.endTransmission();
    delay(100);
    Wire.beginTransmission(0x20);
    Wire.write(0x13);
    Wire.write(0x00);
    Wire.endTransmission();
  }
  
//  Wire.beginTransmission(0x20);
//  Wire.write(0x13);
//  if (ledState == 0x01) {
//    ledState = 0x00;
//  } else {
//    ledState = 0x01;
//  }
//  Wire.write(ledState);
//  Wire.endTransmission();
//  
  selectI2cChannels(I2C_CHANNEL_SDSC3);
  Wire.beginTransmission(0x20);
  Wire.write(0x13);
  Wire.write(0x01);
  Wire.endTransmission();
  delay(100);
  
//  selectI2cChannels(I2C_CHANNEL_SDSC0);
//  Wire.beginTransmission(0x20);
//  Wire.write(0x13);
//  if (ledState == 0x01) {
//    ledState = 0x00;
//  } else {
//    ledState = 0x01;
//  }
//  Wire.write(ledState);
//  Wire.endTransmission();
  
  selectI2cChannels(I2C_CHANNEL_SDSC3);
  Wire.beginTransmission(0x20);
  Wire.write(0x13);
  Wire.write(0x02);
  Wire.endTransmission();
  delay(100);
  
//  selectI2cChannels(I2C_CHANNEL_SDSC0);
//  Wire.beginTransmission(0x20);
//  Wire.write(0x13);
//  if (ledState == 0x01) {
//    ledState = 0x00;
//  } else {
//    ledState = 0x01;
//  }
//  Wire.write(ledState);
//  Wire.endTransmission();
//  
  selectI2cChannels(I2C_CHANNEL_SDSC3);
  Wire.beginTransmission(0x20);
  Wire.write(0x13);
  Wire.write(0x04);
  Wire.endTransmission();
  delay(100);
  
//  selectI2cChannels(I2C_CHANNEL_SDSC0);
//  Wire.beginTransmission(0x20);
//  Wire.write(0x13);
//  if (ledState == 0x01) {
//    ledState = 0x00;
//  } else {
//    ledState = 0x01;
//  }
//  Wire.write(ledState);
//  Wire.endTransmission();
//
  selectI2cChannels(I2C_CHANNEL_SDSC3);
  Wire.beginTransmission(0x20);
  Wire.write(0x13);
  Wire.write(0x08);
  Wire.endTransmission();
  delay(100);

//  selectI2cChannels(I2C_CHANNEL_SDSC0);
//  Wire.beginTransmission(0x20);
//  Wire.write(0x13);
//  if (ledState == 0x01) {
//    ledState = 0x00;
//  } else {
//    ledState = 0x01;
//  }
//  Wire.write(ledState);
//  Wire.endTransmission();
}

void selectI2cChannels(int channels) 

#include <Wire.h>


#define PCA9548ADDR 0x70

