I have connect hardware I use to Arduino in order to use Arudino sound shield.
I've connect it using 4 GPIO cables. I've also wrote small application that set the respected lines to 0 or 1 based on number between 0-15 and wrote Arduino app that read those lines and reassemble them into single number.
Everything works great but now I need to pass a number between 1 and 400
I'll try to see if I have 9 free GPIO ports to connect to, but if I don't I need to pass the number using the exist 4 cables.
Does anyone have any suggestion of how to pass the numbers. The major problem is that my hardware and the Arduino share no timing so I need a protocol that will be reliable enough, and not to slow.