Kunal,

You can download (free) UVI51 from:
ftp://ftp.dte.uvigo.es

Serial port is supported and you can simulate up to 4 micros concurrently. For example, you can use an additional micro to simulate your specific ADC.
UVI51 also simulates several standard peripherals and includes a logic analyzer.

If you decide to use UVI51, I can send you (free, of course) some additional files to break the 500 lines source code limit of the downloadable version.

Alfredo del Rio.