What you need is a simple DELAY and LOOK-UP TABLE program. Plenty of help available on both all over the net. It'll all be over in one loop if you use the hardware timers (and since you won't be using them for anything else, why not?!)

Use the 89c51 (with EEPROM Flash memory) It will reduce the number of external chips, cost less and is more than secure enough for such non-critical applications.

For the code, look at the 8051 programming tutorial section of this site. It is really very good, an easy to learn.

kundi