Heh, I wrote a USB stack for PICs in assembler way back and... yeah, I wouldn't recommend that :-) (the official stack was written in C, but I refused to use C

Heh, I wrote a USB stack for PICs in assembler way back and... yeah, I wouldn't recommend that :-) (the official stack was written in C, but I refused to use C compilers for PICs at the time because they were expensive and terrible; things got better with SDCC, but oh god C18 was bad - thankfully C works very nicely on AVRs). But yes, mixing asm and C should be a lot easier and well documented. The repo I linked is a simple example of how to do it stand-alone, without any libs or Arduino anything, but... yeah. This isn't exactly an Arduino problem; the "template project" issue is pretty common across the embedded industry. But for something as popular as Arduino not to have done a better job is unfortunate.