RAID_ZERO:
Now i want to do this using software interrupts.
This doesn't strike me as a sensible thing to want.
If you are determined, I believe it is possible to configure the ADC so that it will perform repeated conversions and generate an interrupt each time one completes; I suppose it would be possible to implement an interrupt handler to do whatever processing you wanted to the result, and call additional handler functions when thresholds were crossed etc. I highly doubt that this is a sensible thing to do in your project, though.