Apparently it does have built in UART and capable of RS232 etc, but for a apparent trivial status of two signals, seems a little overkill, especially considering the amount of I/O?
M.
Well. Perhaps the other hurdle, or useful bit of advise to the OP would be to use a more modern solution.
Look at more recent microcontrollers, or perhaps a good starting point for him would be an arduino. http://playground.arduino.cc/Learning/OneWire
Sometimes an employer will assign a "simple" task to a new hire, just to see what he is capable of doing on his own. Perhaps this ancient μP is part of a product, and they just want @Pradip Nepali to become familiar with its operation. Sort of a sink-or-swim situation. Who knows? But the nature of the questions reveals a lot about what he doesn't know, and virtually nothing about what he does know (if anything) about programming and using micro-processors. This is, after all is said, a software problem that can be "easily" solved once he either (1) learns how to program or (2) finds someone who will program for him. I am betting that he chooses door #2 and moves on up into project management.