well for various reasons i kind of like the dual-component approach better. even if the teensy host lib is super solid and the prototyping cost is slightly lower, having the roles split makes it a little more flexible w/r/t component choice for other DIY versions or custom boards.
there just don’t seem to be many MCUs that have dual physical USB interfaces and they are gonna require specific custom libraries like the teensy.
that said, not a big deal to support the same API on both platforms.
for this application in particular, it even seems like 2x samd21 would be sufficient; i wouldn’t really feel the lack of an FPU.
with an m4 on the device role, it seems to naturally open the door to doing more processing / sequencing / synthesis, which begs for more I/O and a whole slew of functional decisions.
OTOH , m4 makes lua integration easier.
next week i’m picking up an assortment of the adafruit Feather boards and adapters so should be able to POC any combination of samd51/samd21. in the meantime i have been poking at a super-minimal eLua build for the M0 using integer math (just the VM and interpreter, no modules.) maybe the timing will line up just right.
i have a couple of teensy 3.6s, but in the wrong part of the country. maybe i will pick up another one.
hm, maybe for next step!