I am currently working on a senior design project that is using a microcontroller hooked to a keypad. The keypad is using a bcd encoder 74147 chip. I am reading in the 4bit number into input ports A0-A3. Im reading the number in, placing the number in W and using a debounce routine. My problem is I need to accept 4 user inputs one at a time and store them one at a time. I know how to get to the debounce routine but after that I dont know how to store the number(say digit_1) and when the next input comes in store that in another location(say digit_2).

I have seen some other rountines that use a matrix keypad setup. This is my first major project so I could be doing this completely wrong but at this point I would like to keep going in the direction.