Like you would any other vendor! See who has what you want/need. How much they want for it. What their reputation is. etc.
Then, see who *else* has "something that you can *tweek*" to do the same job -- possibly better/worse -- and repeat the process.
Finally, make a "value judgement" on all of the candidates that fall through the above process.
selling the
Atmel has more
I don't think you will find "the same part" from any two vendors. The ARM world is like the "stereo" (HiFi) business of ages past (modern parallel would be multimedia): you bought a turntable from vendor A, the *stylus* for that turntable from vendor B, the (phono) preamp from vendor C, amplifier from vendor D, speakers from vendor E, etc. Until you got the "system" that fit your price/performance/ego.
With ARM, each vendor *packages* various "components" (referencing the above analogy) into an MCU. So, the processing power of the "core", amount of memory (and flavors thereof) included/supported, other peripherals onboard, etc. varies.
In theory, you can find The Ideal MCU for your application -- but, chances are, it is only sold by *one* vendor (though the various components inside it may appear in a smattering of offerings from other vendors... though not in the exact same configuration).
shocking.
I dunno... google doesn't tell me which *car* is "right" for me, either! Amazing!
That's a value judgement. Do you want to establish a relationship with
*one* company? (there are pros and cons, of course) Do you want to tailor your solutions to your problems (or pick the closest fit from the offerings of that *one* company)?That's why they call it "Engineering" instead of "shopping for shoes"...
--don