[quote user="rahul singh"] cant i design a circuit on the software verify it..[/quote]
In theory yes - but your modeling, simulating & anticipating any/all "normal complications" - bit beyond most mortals. (and far beyond - this reporter)
Your project bundles a motor, multiple sensors, power components, a battery - and an MCU. Risk-Reward should rise in your consideration - doing this all on "paper" - or "in your head" - minus strongly suggested Eval Board(s) - generates a risk-coefficient far in excess of any, (hoped for) "rapid reward."
Real world events/measures/findings quickly reveal via a properly chosen - and routed/harnessed Eval board. Read any vendor's "errata" - do you think all of it was gleaned rapidly - and strictly via simulation? (SW)
Focusing on your objective - the combination/marriage of low-level analog adjacent to power components (i.e. single board solution) - often proves challenging. Separate boards enable you to better isolate these confounding tasks - and may provide a "standard" for your later, single board design to attempt to match. (absent - should you launch via single board...)
