Understanding MCU vs MPU

Many people have doubt about MCU and MCU, What are different between MCU and MPU?

MCU (Microcontroller Unit, uC)

MCU or Microcontroller, consist of 2 word are Micro and Controller, it mean small controller, small computer which inside microcontroller are Processor, memory, peripheral ADC, Timer, USART, USART or complex module such as AES module.

MCU Advantages

  • Cheap Price
  • MCU use Embedded on Chip Flash memory, fast boot, very low startup time
  • Real time application, very low interrupt latency
  • Low power

MCU disadvantages

  • limit size of Flash memory, now maximum size of MCU flash on market is 2Mbytes
  • not suitable for Operation System application because low memory and slow processor, Linux or Android OS need processor speed 300~400 DMIPS but MCU cortex M4 has speed 150 DMIPS.


MPU (Microprocessor Unit, uP)

Microprocessor is processor, which has instruction set on IC. If we would like to use Microprocessor we have to connect Microprocessor with other peripheral such as External memory, Microprocessor cannot work standalone.

MPU Advantages

  • Fast speed processor, example ARM Cortex-A5 MPU has speed up to 850 DMIPS
  • Can upgrade memory from Mbytes to Gbytes

MPU disadvantages

  • Application on MPU may respond slower than MCU because MPU use external memory, which has to connect to external device.
  • It has to connect many external devices so MPU board will larger than MCU board


When use MCU and MPU

Both are has Advantage and Disadvantage. Which depend on your application, you have to tradeoff it.

For example, MCU application needs Time-sensitive application such as Motor control, Safety critical, Robot, pick and place.

For MPU application need full OS application, which use large memory such as GUI interface, touch screen HMIs, High-speed communication Gigabit Ethernet, Plug and Play hardware.