Understanding the similarities and differences between MCU and CPU in one article

I believe many people still don't know what a single-chip microcomputer is . They also don't know what the role of a single-chip microcomputer is. A single-chip microcomputer is abbreviated as a single-chip microcontroller. It is not a chip that completes a certain logical function, but a computer system integrated into a chip, which is equivalent to a microcomputer, because it was first used in the field of industrial control. The single-chip microcomputer is developed from a dedicated processor with only a CPU in the chip. The earliest design concept was to make the computer system smaller and easier to integrate into complex and demanding control devices by integrating a large number of peripherals and CPUs into one chip. Intel's Z80 was the first processor designed according to this idea. Since then, the development of single-chip microcomputers and dedicated processors has gone their separate ways.

The picture comes from the Internet

As we all know, our computers are mainly composed of a central processing unit (CPU) (for calculation and control), random access memory (RAM) (data storage), memory (ROM) (program storage), and input/output devices (I/O) (serial port, parallel output port, etc.). Installed on a printed circuit board called a motherboard, it is our personal computer.

It is easy to understand the MCU by considering it as a whole and dividing it into four parts. After these things (CPU, hard disk, memory, motherboard, etc.) are made with integrated blocks, it looks like the following figure:

Standalone

It becomes the "single chip microcomputer" we are going to learn. Inside the single chip, CPU, hard disk, memory, motherboard, etc. are other names.

1) CPU (Central Processing Unit). It is the core component of the microcontroller, including the arithmetic unit and the controller. The arithmetic unit is the arithmetic logic unit (ALU), which performs arithmetic and logical operations. The controller is generally composed of an instruction register, an instruction decoder, a timing circuit, and a control circuit. Its function is to complete instruction fetching, decode instructions into various micro-operations, and execute instructions, while controlling the various components of the computer to work in an orderly manner.

CPU internal diagram

2) The memory in the computer is called data storage in the microcontroller, also called random access memory. It is represented by RAM (Random Access Memery). Its function is to store intermediate results of calculations, temporary storage and buffering of data, flag bits, etc. Its characteristic is that data will be lost after power failure.

Program Memory

3) The hard disk in the computer is called program memory, also called read-only memory in the single-chip microcomputer. It is represented by ROM (Read only memory). Its function is similar to that of the hard disk, and it is used to store user programs. Its characteristics are: data will not be lost after power failure.

4) Input/output device I/O "motherboard", in the microcontroller, is called I/O (input and output device), of course it also includes serial port, parallel port, timer, chronometer and so on.

The application fields of single-chip microcomputers are very wide, such as intelligent instruments, real-time industrial control, communication equipment, navigation systems, household appliances, etc. Once a variety of products use single-chip microcomputers, they can play a role in upgrading the products. The adjective "intelligent" is often added before the product name, such as intelligent washing machines. Therefore, the study, development and application of single-chip microcomputers will create a group of scientists and engineers in computer application and intelligent control.