The pins used in the diagram are just examples, it's the pins in the code you want to go by. Then again, you could always changes those too, but as long as you know which pin is what (clk,data,reset and busy) you can code it to work on any combination of arduino pins. Just note, if you plan on using the serial monitor, don't have anything in digital pins 0 & 1 , otherwise you may get incorrect results.