Microcontroller vs microprocessor (MCU vs MPU)

A microcontroller (MCU) puts a processor core, flash memory, RAM and peripherals (timers, ADCs, communication ports) on one chip. It boots almost instantly, can sleep at very low power, and runs firmware written directly for the hardware or on a small real-time operating system. Most thermostats, sensors, motor controllers and wearables use MCUs.

A microprocessor (MPU), or application processor, has far more computing power and a memory management unit, but needs external RAM and storage and typically runs embedded Linux or another full operating system. It suits rich touchscreens, cameras, complex networking, local AI inference and anything that benefits from existing Linux software.

Where it bites: an MPU design brings a more complex board (high-speed memory routing, more power rails), longer boot times, higher idle power, and an operating system that must be patched for security for the life of the product. Many products pair the two: an MPU for the user interface and connectivity, an MCU for real-time control and safety functions.