English Name: Single Chip Microcomputer &; Embedded system means that the system can complete a function alone, and single chip microcomputer is only part of this purpose. Embedded system means that a microprocessor is "embedded" into the actual application system to form an embedded system, which can be divided into hardware part and software part.
The hardware part is mainly realized in the following ways:
1. It is composed of mpu as the core, such as arm.
2. With mcu as the core, there are various single-chip computers, which mainly integrate the processor and the memory on one chip.
3. With dsp as the core, it is mainly used to process voice and graphics.
4. It is what people call sop.
In the software part, some have embedded operating system and some don't. This is mainly determined by the size of the system. 1. Embedded application in microcomputer era
Electronic digital computer was born in 1946. In the long historical process since then, computers have always been large and expensive equipment to realize numerical calculation in special computer rooms. It was not until the advent of microprocessors in the 1970s that computers experienced historic changes. Microprocessor-based microcomputers are rapidly coming out of the computer room because of their small size, low price and high reliability. Microcomputer based on high-speed numerical calculation ability has aroused the interest of control professionals, and it is required to embed microcomputer into the object system to realize intelligent control of the object system. For example, after electrical and mechanical strengthening, a microcomputer is equipped with various peripheral interface circuits and installed on a large ship to form an autopilot or marine engine condition monitoring system. In this way, the computer lost its original form and general computer functions. In order to be different from the original general computer system, the computer is embedded into the object system to realize the intelligent control of the object system, which is called embedded computer system. Therefore, the embedded system was born in the microcomputer era, and the embedded essence of the embedded system is to embed a computer into an object system, which are the basic starting points for understanding the embedded system.
2. Two branches of modern computer technology.
Because the embedded computer system should be embedded into the object system to realize intelligent control of the object, it has completely different technical requirements and development direction from the general computer system. The technical requirement of general computer system is high-speed and massive numerical calculation; The development direction of technology is the infinite improvement of bus speed and the infinite expansion of storage capacity. The technical requirement of embedded computer system is the intelligent control ability of the object; The development direction of technology is embedded performance, control ability and control reliability closely related to the object system.
In the early days, people reluctantly reformed the general computer system to realize embedded applications in large-scale equipment. However, for many object systems (such as household appliances, instrumentation, industrial control units, etc.). ), it is impossible to embed into general computer system, and the technical development direction of embedded system and general computer system is completely different. Therefore, it is necessary to develop general computer system and embedded computer system respectively, which has formed two branches of the development of modern computer technology.
If the appearance of microcomputer makes the computer enter the stage of modern computer development, then the birth of embedded computer system marks that the computer has entered the era of parallel development of general computer system and embedded computer system, which led to the high-speed development of computers at the end of the 20th century.
3. Milestones in the development of the two branches
The specialized development between general-purpose computer system and embedded computer system led to the rapid development of computer technology in the late 20th century and early 20th century. The computer professional field concentrates on developing the software and hardware technology of general computer system, regardless of the embedded application requirements, and the general microprocessor changes rapidly from 286, 386 and 486 to Pentium series; The operating system has rapidly expanded the computer's file processing ability based on high-speed and massive data, making the general computer system enter a perfect stage.
Embedded computer system has embarked on a completely different road, which is the road of single chip development. It mobilized the original manufacturers and professionals in the traditional electronic system field, took over the embedded system originated from the computer field, and undertook the historical task of developing and popularizing the embedded system, so that the traditional electronic system quickly developed into the era of intelligent modern electronic system.
Therefore, the milestone significance of the two branches of modern computer technology development lies in that it not only forms a specialized division of labor in computer development, but also extends the task of developing computer technology to the traditional electronic system field, making computers a powerful tool for human society to enter the era of comprehensive intelligence. 1. Single chip microcomputer pioneered the independent development of embedded systems.
Although the embedded system originated from the era of microcomputer, the size, price and reliability of microcomputer can not meet the embedded application requirements of most target systems, so the embedded system must take the road of independent development. This road is a chip road. The computer is made on one chip, thus creating the era of single chip microcomputer for independent development of embedded systems.
When exploring the development path of single chip microcomputer, there have been two modes, namely "σ mode" and "innovation mode". "σ mode" is essentially a general-purpose computer direct chip mode, which cuts the basic units in the general-purpose computer system and integrates them on a chip to form a single chip; "Innovation Mode" designs a brand-new architecture, microprocessor, instruction system, bus mode and management mode according to the requirements of embedded applications. MCS-48 and MCS-5 1 of Intel Corporation are monolithic embedded systems (monolithic microcomputers) developed according to innovative modes. MCS-5 1 is an integrated embedded system based on MCS-48. History has proved that "innovation mode" is the correct way for independent development of embedded systems, and the architecture of MCS-5 1 has therefore become a typical architecture of monolithic embedded systems.
2. The development history of single chip microcomputer technology
Single-chip microcomputer was born in the late 1970s and has gone through three stages: SCM, MCU and SoC.
1.SCM is the stage of single chip microcomputer, which mainly seeks the best architecture of embedded system in the form of single chip microcomputer. The success of "innovation mode" has laid a completely different development path between single chip microcomputer and general computer. Intel has made great contributions to the independent development of embedded systems.
2.MCU is the stage of microcontroller unit, and its main technical development direction is to continuously expand various peripheral circuits and interface circuits that meet the requirements of the target system and highlight its intelligent control ability in embedded applications. The fields it involves are all related to the object system, so the important task of developing MCU inevitably falls on the electrical and electronic technology manufacturers. From this point of view, Intel's gradual fading out of MCU also has its objective factors. In the development of MCU, the most famous manufacturer is Philips.
By virtue of its great advantages in embedded applications, Philips has rapidly developed MCS-5 1 from single chip microcomputer to microcontroller. Therefore, when we review the development path of embedded systems, don't forget the historical achievements of Intel and Philips.
3. Single-chip microcomputer is the independent development path of embedded system, and the important factor to develop to MCU stage is to seek the biggest solution of application system on chip; Therefore, the development of dedicated single-chip microcomputer naturally forms the trend of SoC. With the development of microelectronic technology, ic design and EDA tools, the design of single chip microcomputer application system based on SoC will have great development. Therefore, the understanding of MCU can be extended from MCU and MCU to MCU application system.