A microcontroller (also known as a microcontrol unit (MCU) )is a microprocessor chip designed for application-specific control processing, operating at a frequency (1MHz to 200 MHz) and consuming less power than the CPU/MPU of PCs and mobile phones. Today's MCUs are system-on-chips (SoCs), integrating a variety of functional modules and interfaces on a single chip, including memory, I/O ports, clocks, A/D conversion, PWM, etc., as well as SPI, I2C, ISP and other data transmission interfaces.

According to the number of bits, MCUs can be divided into 4-bit, 8-bit, 16-bit, 32-bit and 64-bit microprocessors, and now 32-bit MCUs have become mainstream and are gradually replacing the applications and markets dominated by 8/16-bit MCUs in the past. If divided according to the instruction set architecture (ISA), MCU types include 8051, Arm, MIPS, RISC-V, POWER and other microprocessors. MCUs based on Arm Cortex-M series core IP have become the mainstream of the 32-bit MCU market, and in recent years, open source RISC-V microprocessors have also become popular, especially in the emerging field of Internet of Things.