keyPAD AND lcd INTERFACE.

Dear all.

I am using Below circuit for interfacing Lcd and keypad. http://www.freetronics.com/pages/16x2-lcd-shield-quickstart-guide#.Uv9jb87pegI. Basically i completed above code and seems working fine. Now plan to build algorithms such that i configure data like date , time, latitude, longitude . after Modifying Display Date and time On screen with Desired angle calculation. Desired angle might Refer to motor Encoder output0-5v converted 0-360 degree.Now i Need Suggestion On Building the code. The Algorithms Steps. I can modify @ any instant. If change time Desired angle has to change accordingly. After changing It show date and time with angle Desired position.

Any one Here to help it out