It was a friday morning, between 8 and 10h when we (Alberto and me) were trying to do a PI practice. We were programming the card we use there so that it sent a key over the USB when a button was pressed in the same card. The problem was that we were sending a key and right after a backspace while waiting a bit so the user could see it.

We made it in the polling function so it was called continuously. When we changed the time that the timer was waiting, the program stopped working because the key was pushed too much time and too many chars appeared. When we showed that to the teacher he looked at it and asked us: Where do you initialize to 0 the buffer in the loop?

There was no loop, we used the polling function.