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

#define AIN1 6
#define AIN2 5
#define PWMA 4
#define STBY 7

Adafruit_MCP23017 mcp;


void setup()
{
  mcp.begin();

  mcp.pinMode(AIN1, OUTPUT);
  mcp.pinMode(AIN2, OUTPUT);
  pinMode(PWMA, OUTPUT);
  mcp.pinMode(STBY, OUTPUT);
  mcp.digitalWrite(STBY, HIGH);
}


void loop()
{
   mcp.digitalWrite(AIN1, HIGH);
   mcp.digitalWrite(AIN2, LOW);
   analogWrite(PWMA, 255);
}