Recommended · for advanced
No USB? No problem. (33c3)
Why people recommend it
A conference talk on implementing USB entirely in software on a small ARM microcontroller, cited when people ask about USB without dedicated hardware.
Watch for: Deep firmware detail, not a beginner topic
In their words
Interesting 33c3 video explaining as well:
INL on electronics.stackexchange.com, Jan 2017. CC BY-SA.