MCUs

MCU stands for microcontroller unit, an integrated circuit designed to control a specific task or system. A typical MCU combines a processor core, on-chip memory (Flash or ROM for code, RAM for data), and a variety of peripherals on a single chip. It is intended for embedded applications requiring deterministic timing, small form factors, and low power consumption. MCUs are distinguished from general-purpose microprocessors by their integration of memory and peripherals and by their emphasis on low power and real-time performance.

Most MCU cores are 8-, 16-, or 32-bit, with 32-bit Cortex-M, AVR, PIC, MSP430, Renesas RL78, and 8051 families common in contemporary devices. On-chip flash memory stores firmware; SRAM holds runtime data; and peripherals include timers, counters, analog-to-digital converters, digital-to-analog converters, and communication interfaces such as UART/USART, SPI, I2C, CAN, USB, and often Ethernet or wireless radio interfaces. Some MCUs include security features, safety mechanisms, and multiple power modes to extend battery life.

Compared with microprocessors, MCUs generally run from on-chip memory, operate at lower clock rates, and are designed for real-time control with predictable latency. They may run simple real-time operating systems or run firmware without an OS.

Applications span consumer electronics, automotive controls, industrial automation, IoT sensors, medical devices, and appliances. Development typically uses C or C++, with vendor-provided software development kits and hardware abstraction layers; debugging and programming tools vary by vendor, with common IDEs and compilers supporting multiple MCU families.

Notable MCU families include ARM Cortex-M based STM32, NXP LPC, Microchip PIC, Atmel AVR (now Microchip), TI MSP430, Renesas RA/RL78 and a growing line based on RISC-V.