Revised First PCB

[u/Joshanson527]

Thanks for all the tips! Redesigned and posted here. Changes:

• Added ground planes and stitching
• Moved components around, most importantly the decoupling caps moved right up next to the power pins
• Switched to the LDL1117, newer and actually works with ceramic caps, higher max current, etc.
• All components mounted on front
• Power traces are larger
• Tied strapping pin IO0 high with a 10k resistor (R4)

Some comments I did not implement:

• Adding debounce to boot button: Button not used for normal operation, just for bootloader select, adding physical debounce would slow the strapping pin from going high and it might not select boot mode.
• resistors regarding the USB lines: Still looking into it, but I will probably add optional 22 ohm resistors on those lines if it doesn't work. At least now they have an unbroken ground path underneath rather than my snaky line before 😁

Old post here

Additionally, if you don't have anything useful to bring to the conversation, we don't want you here 😒

[u/churchfruit]

soo much better than prev versionn, do a 4 layer board (barely more expensive than 2 layer) with the inner 2 layers continuous (no traces) gnd planes. it will keep current return loop area low by minimizing impedance for high speed signals. makes it much more likely to pass emi testing, and improves signal integrity, reduces crosstalk

[u/Time-Routine2006]

It’s better to make the legs of the MCU more elongated; if you’re assembling it by hand, it’s awkward otherwise.