OK - thanks for that.
I’d read the ArduPilot wiki about FETtec.
Maybe with what I’ve learned so far, it will make more sense when I read it again. BTW - there’s a note at the bottom of the wiki that says something about 2M baud and half duplex not being available. Both show up as options in Mission Planner.
You may recall I struggled figuring out how to run the FETtec configurator - using the info on the wiki. I got a helpful reply back from @TeeZee . It’s really something to have to make a hardware implementation of half duplex. Fortunately, it was easy enough to make a harness pig-tail that allows quick hook-up to my USB/serial adapter. I simply incorporated the required diode into the harness. Works great - except that the ESC telemetry port is tied up, and not available for implementing the FETtec protocol.
The documentation and @TeeZee reported that the serial connection for communicating to the ESC requires 2M baud. I found it works fine at 115,200 - and just about any other baud rate I tried. That left me wondering how well this device is documented and understood.
It’s nice to know that the firmware is elegant and concise. But as an implementer, not a developer, that’s not an advantage. Any advantage would stem from operational considerations - i.e. more efficient, more responsive, better telemetry. And as my missions are automated, not FPV, things like latency are less important.
Given the large number of FETtec specific parameters and parameter options, I get the impression that the DEV’s have been pretty enthusiastic about this ESC. I just wish I knew why. My best guess is the thrust has come from people with large high-power aircraft - where there aren’t ESC’s large enough and still support BLHeli_32 to get sinusoidal commutation. Or maybe it’s the FETtech implementation of FOC. But that’s just a guess.