Field-oriented Control schemes modulate phase currents at high frequency; the feedback loop must be much faster than the motor phases. Until fairly recently, this stuff was the exclusive province of dedicated ICs (Trinamic et al.) and FPGA. Today, FoC can be done in (mostly) software with MCUs.

Fast feedback loops are also necessary in SMPS, another area where precision, low latency MCU peripherals and software are actively displacing traditional approaches.