Wow - A lot changed since the first time I looked at this! There was less to clean up, too.
Updated versions in [/url]https://drive.google.com/drive/u/0/folders/0B6dMB5dovDUZYzhjY2M1NmEtZmI2NC00MDZkLTliODMtOWYzNjQyZmViNWEy[/url]
A couple design comments:
- Using an SMT reset switch might be advantageous, and cheaper to assemble.
- Does your micro-SD socket allow traces underneath the socket? Some don't...
"Review" comments:
- A lot of what I did was "centering" traces leaving the ARM SMTs. There are "issues" with routing grid vs IC grid, and a lot of them had little tiny diagonal trace segments causing the traces to be off-center. Most were barely noticeable, and I don't know if any were "dangerous", but they're all centered now.
- I increased the power trace clearance to 10mil and did a DRC check to ensure that all the traces/vias conformed EXCEPT for the ARM itself (whose pins are not 10mil apart!)
- This was mostly accomplished by shifting GND vias a tiny bit toward the center of their flood areas. I eliminated a couple gnd vias for not having any relevant flood on one side or the other, and being otherwise difficult to get to conform.
- You probably want most of the Vias tented. Do this by modifying the "limit" parameter of the "masks" DRC panel. In my version I set it to 0.5mm (so all vias 0.5mm or less will not have solder mask holes.)
I'd say ditch the Arduino "dog ear styling" and go with plain rounded corners, like we did for "Freeduino", but that's just me being style-less 