DSP and all that jazz
It turns out Analog Devices buried their 21xx DSP mcu into motor controller version in a SOIC-28 package.
I trawled the internet and found an archive of the software tools to program and load software onto these toys.
The chip (admc32x and admcf32x) are still available for a couple of dollars a pop, though they are no longer produced.
Moreover, there are more modern turnkey chips out there (see Allegro Microsystems A4960 itself obsolete 😉 so why bother.
Pure arse sentimental value.
I coded on these 21xx and 21xxx chips yonks ago.
Turns out there are about 20 application notes you can grab off the web for these chips that talks about the nuances of motor control.