Hello Babar,

Here is a copleted project with circuit diagram, pcb and source code. If you need the explanation you need to buy the book, if you are not able to locate it , let me know I'll scan the document and upload the same.

It uses AT89S8252, can be converted to any MCS -51 uC having an external IIC eeprom.

http://www.elektor-electronics.co.uk/dl/dl.htm

Rgds
Raj Shetgar