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Microcontroller Overview

Definition: A microcontroller is a single chip containing at least a CPU, non-volatile memory, volatile memory, a timer and an I/O control unit.

Basically a microcontroller can be described as a computer on a chip. The difference between a microcontroller and a regular PC is that the PC is a general purpose computer while a microcontroller is a computer dedicated to one or just a few tasks.

A microcontroller apart from the above mentioned components usually also include, but not limited to, serial communication capabilities, interrupt controls and analog I/O capabilities. The figure below gives the basic layout of a general AVR microcontroller.
Microcontoller Components.png

Microcontroller (MCU) vs Microprocessor

What is a microcontroller?

A Microcontroller is basically a computer on a chip. It differs form normal desktop or laptop computers in that a microcontroller is an application specific computer that usually runs a single program performing dedicated task(s) while the the later two are general purpose computers that can run numerous programs depending on a users needs. A microcontroller contains on chip CPU, input/output interface, memory, clock, timer, and an assortment of of other peripherals.

A Microprocessor on the other hand is just a CPU one has to add externally memory, clock, input/output interfaces, timer and all other needed peripheral. This is the reason a microprocessor has so many pins.


Advantages of a similar microcontroller vs microprocessor product

  • Product smaller - A microcontroller product has many components on one chip and so is more compact. With a microprocessor product one have to add several other chips and so its bulky.
  • Cheaper - All the components on a microcontroller is manufacturer on a single chip and so is mush cheaper than having to manufacture several chips as is the case for a microprocessor system.
  • AVR Tutorials hopes that this tutorial on microcontroller vs microprocessor systems was beneficial to you and looks for to your continued visits for all your microcontroller tutorial needs.


  • ROM (or flash-based MCU) - CPU can only read, can not write, save user program in ROM
  • RAM - CPU can write or read data, when power lost data also lose


  • 标准51单片机是12T的,就是说12个时钟周期(晶振周期,例如12M的,周期是1/12M,单位秒),机器做一个指令周期,刚好就是1/12M*12=1uS,常见指令例如_nop_就是一个周期,刚好1uS,其他的大多多于一个周期,乘除法更多。所以如果计算指令时间可以这样算。



This category has the following 13 subcategories, out of 13 total.

Pages in category "MCUs"

The following 5 pages are in this category, out of 5 total.