There was a 24 MHz 16-bit microcontroller out in 1985 or so: The Fairchild 9445 https://www.cpushack.com/2017/11/14/cpu-of-the-day-fairchild-f9445-the-microfla

There was a 24 MHz 16-bit microcontroller out in 1985 or so: The Fairchild 9445 https://www.cpushack.com/2017/11/14/cpu-of-the-day-fairchild-f9445-the-microflame-flames-out/ https://www.cpushack.com/2017/11/14/cpu-of-the-day-fairchild... It ran the Nova 4 instruction set. We were using it for a cutting-edge project: and all Digital Radio receiver, for EVLF communications to submarines in the 16 kHz range.