// MCP23017 Example: Slow key press reaction.
//
// Toggle LEDs and detect keypress.
//
// Example code showing slow reaction of 'button' 
// LED to keypress. Leading into why interrupts
// are useful (See next example).
//
// Copyright : John Main
// Free for non commercial use.

#include <Wire.h> 
#include <Adafruit_MCP23017.h> 

#define MCP_LED1 7
#define MCP_INPUTPIN 8
#define MCP_LEDTOG1 11
#define MCP_LEDTOG2 4

Adafruit_MCP23017 mcp;
  
void setup() {  
  mcp.begin();      // Default device address 0

  mcp.pinMode(MCP_LEDTOG1, OUTPUT);  // Toggle LED 1
  mcp.pinMode(MCP_LEDTOG2, OUTPUT);  // Toggle LED 2
  
  mcp.pinMode(MCP_LED1, OUTPUT);     // LED output
  mcp.digitalWrite(MCP_LED1, HIGH);

  mcp.pinMode(MCP_INPUTPIN,INPUT);   // Button i/p to GND
  mcp.pullUp(MCP_INPUTPIN,HIGH);     // Puled high to ~100k
}

// Alternate LEDTOG1 and LEDTOG2.
// Transfer pin input to LED1.
void loop() {

  delay(300);

  mcp.digitalWrite(MCP_LEDTOG1, HIGH);
  mcp.digitalWrite(MCP_LEDTOG2, LOW);

  delay(300);

  mcp.digitalWrite(MCP_LEDTOG1, LOW);
  mcp.digitalWrite(MCP_LEDTOG2, HIGH);
  
  // Transfer input pin state to LED1
  if (mcp.digitalRead(MCP_INPUTPIN)) {
     mcp.digitalWrite(MCP_LED1,HIGH);
  } else {
     mcp.digitalWrite(MCP_LED1,LOW);
  }
  
}

    

/*
 Example 41.2 - Microchip MCP23017 with Arduino
 http://tronixstuff.com/tutorials > chapter 41
 John Boxall | CC by-sa-nc
 */
// pins 15~17 to GND, I2C bus address is 0x20
#include "Wire.h"
byte inputs=0;
void setup()
{
 Serial.begin(9600);
 Wire.begin(); // wake up I2C bus
}
void loop()
{
 Wire.beginTransmission(0x20);
 Wire.write(0x13); // set MCP23017 memory pointer to GPIOB address
 Wire.endTransmission();
 Wire.requestFrom(0x20, 1); // request one byte of data from MCP20317
 inputs=Wire.read(); // store the incoming byte into "inputs"
 if (inputs>0) // if a button was pressed
 {
 Serial.println(inputs, BIN); // display the contents of the GPIOB register in binary
 delay(200); // for debounce
 }
}
    

#include "Adafruit_MCP23017.h"
Adafruit_MCP23017 mcp1;
Adafruit_MCP23017 mcp2;
void setup() {
mcp1.begin(0);
mcp2.begin(1);

mcp1.pinMode(0, INPUT);
mcp1.pinMode(1, OUTPUT);
mcp2.pinMode(1, OUTPUT);
Serial.begin(9600);
pinMode(13, OUTPUT);
}

void loop() {
mcp2.digitalWrite(1, mcp1.digitalRead(0));
digitalWrite(13, mcp1.digitalRead(0));
mcp1.digitalWrite(1, mcp1.digitalRead(0));
if(mcp1.digitalRead(1) == HIGH){
Serial.println("Led whent HIGH");
}
}