[hardware] What are the ascii values of up down left right?

Really the answer to this question depends on what operating system and programming language you are using. There is no "ASCII code" per se. The operating system detects you hit an arrow key and triggers an event that programs can capture. For example, on modern Windows machines, you would get a WM_KEYUP or WM_KEYDOWN event. It passes a 16-bit value usually to determine which key was pushed.