/*************************************************** 
  This is a library for our I2C LED Backpacks

  Designed specifically to work with the Adafruit LED Matrix backpacks 
  ----> http://www.adafruit.com/products/872
  ----> http://www.adafruit.com/products/871
  ----> http://www.adafruit.com/products/870

  These displays use I2C to communicate, 2 pins are required to 
  interface. There are multiple selectable I2C addresses. For backpacks
  with 2 Address Select pins: 0x70, 0x71, 0x72 or 0x73. For backpacks
  with 3 Address Select pins: 0x70 thru 0x77

  Adafruit invests time and resources providing this open source code, 
  please support Adafruit and open-source hardware by purchasing 
  products from Adafruit!

  Written by Limor Fried/Ladyada for Adafruit Industries.  
  BSD license, all text above must be included in any redistribution
 ****************************************************/

#include <Wire.h>
#include "Adafruit_LEDBackpack.h"
#include "Adafruit_GFX.h"

#ifndef _BV
  #define _BV(bit) (1<<(bit))
#endif


Adafruit_LEDBackpack matrix = Adafruit_LEDBackpack();

uint8_t counter = 0;

void setup() {
  Serial.begin(9600);
  Serial.println("HT16K33 test");
  
  matrix.begin(0x70);  // pass in the address
}

void loop() {
  // paint one LED per row. The HT16K33 internal memory looks like
  // a 8x16 bit matrix (8 rows, 16 columns)
  for (uint8_t i=0; i<8; i++) {
    // draw a diagonal row of pixels
    matrix.displaybuffer[i] = _BV((counter+i) % 16) | _BV((counter+i+8) % 16)  ;
  }
  // write the changes we just made to the display
  matrix.writeDisplay();
  delay(100);

  counter++;
  if (counter >= 16) counter = 0;  
}
