Just out of curiosity; not that I know anything about microprocessor chips, what’s the difference between these two? Big difference in cost or capability? I can see a size difference but was wondering if there are other advantages to one over the other? Nope, not wanting to design hardware ,just wondering.
Thanks
Top
STM32F401 which is an 64 pin ARM Cortex M4 running at 84MHz, 512kb Flash and 96kb ram
Bottom
ATSAMD21 which us an 48 pin ARM Cortex M0 running at 48MHz, 256kb Flash and 32kb ram
Cortex M4’s have more goodies in them - extra pins just mean…extra pins 
STM’s in my humble opinion are the ducks nuts and are the ones all the cool kids use these days 
Top one can run C# and visual basic, with full debugging in visual studio… And many other things.
The other one can barely do the basics
