What is a microcontroller?
First, let’s understand what exactly a microcontroller is. The core of an embedded system is the embedded processor. Embedded processors can generally be divided into the following types.
Embedded Microcontroller MCU (Micro Control Unit)
Embedded DSP Processor (Digital Signal Processor)
Embedded Microprocessor MPU (Micro Processor Unit)
Embedded System-on-Chip (SoC)
Programmable System on Chip SoPC (System on a Programmable Chip)
Our microcontrollers belong to embedded microcontroller MCU (Micro Control Unit). MCU internal integration ROM/RAM, bus logic, timing/counter, watchdog, I/O, serial port, A/D, D/A, FLASH, etc.. Typical representatives such as 8051, 8096, C8051F, etc. Microcontroller is a chip (Chip) integrated with the CPU, SRAM, Flash and other modules needed to implement a microcomputer system on a Chip, so it is called Single Chip Microcomputer, that is, a single chip. It is actually a kind of integrated circuit chip, which is a super large-scale integrated circuit technology, the CPU, RAM, ROM, input/output and interrupt system, timer/counter and other functions are stuffed into a silicon chip to turn it into an ultra-small computer. In that case, the microcontroller is not an embedded system? Don’t worry, let’s read on.
The term “microcontroller” is actually an old name. In that era, the semiconductor process is still in its infancy, the integration capacity is very poor, often a CPU chip, SRAM a chip, Flash a chip, the need for interrupts, then there must be a special chip to deal with interrupts, so a complete available computer system is a lot of chips (Chip) to do on a PCB board composition. Different functions can not be done into a chip (Chip), so there will be a multi-chip machine. Now semiconductor technology has long been very advanced, so there is no multi-chip machine. However, the name “microcontroller” has been used until now. Microcontroller technology was born in the late 1970’s. In the early days, it was 4-bit, and later developed into 8-bit, 16-bit, and 32-bit. It really rose to prominence in the 8-bit era. 8-bit microcontrollers are very powerful and are widely used in industrial control, instrumentation, home appliances, automobiles and other fields. When we study microcontrollers, we often hear a word – 51 microcontroller. Let’s find out what it really is.
51 microcontroller, in fact, is the collective name of a series of microcontrollers. This series of microcontrollers, compatible with the Intel 8031 instruction system. Their originator, the Intel (Intel) 8004 microcontroller. Note that the 51 microcontrollers are not all products of Intel. Including ATMEL (Edmel), Philips (Philips), Huabang, Dallas (Dallas), Siemens (Siemens), STC (domestic macrochip) and other companies, there are also many products belong to the 51 microcontroller series. ATMEL company’s 51 microcontroller, AT89C51 which is a 51 microcontroller development board, the middle of that chip is 51 microcontroller.
51 microcontroller was once the most mainstream and widely used microcontroller on the market for a long time, occupying a large market share. 51 microcontroller is actually placed in the present without technical advantages, is a very old technology. The reason for its tenacity, in addition to its former popularity, is that Intel has completely opened up the copyright of the 51 core. Therefore, no matter any unit or individual, they can use 51 microcontroller without any fear, without paying and without worrying about the risk of copyright, so many schools are also using this. In addition, 51 microcontroller has a strong stock base and mass base. Many old projects are using the 51 microcontroller, for cost reasons, sometimes only continue to follow the 51 microcontroller technology to upgrade. Moreover, many of the older generation of engineers are proficient in 51 microcontroller development technology. Therefore, the vitality of the 51 microcontroller to continue.
What is embedded?
An embedded system is a dedicated computer system that is used as part of a device or equipment. Usually, an embedded system is an embedded processor control board where the control program is stored in ROM. In fact, all devices with digital interfaces, such as watches, microwave ovens, VCRs, cars, etc., use embedded systems. Some embedded systems also contain operating systems, but most embedded systems implement the entire control logic from a single program. Defined from the application object, embedded system is the synthesis of software and hardware, can also cover mechanical and other ancillary devices. Domestic generally agreed definition of embedded system is: application-centered, based on computer technology, hardware and software can be cut, adapt to the application system on the function, reliability, cost, volume, power consumption and other strict requirements of the special computer system. Embedded systems are specifically used in which “special” direction? The following are some examples.
Office automation: printers, copiers, fax machines
Military and aerospace products: drones, radar, combat robots
Home appliance products: digital TV, sweeping robot, smart home appliance
Medical electronics products: biochemical analyzers, blood analyzers, CT
Automotive electronics products: engine control, security systems, car navigation and entertainment systems
Network communication products: communication type switching equipment, network equipment (switches, routers, network security)
Communication and entertainment: cell phones, digital cameras, music players, wearable electronics, PSP game consoles
Industrial control products: industrial control machines, interactive terminals (POS, ATM), security monitoring, data acquisition and transmission, instrumentation
All of the above-mentioned fields use embedded systems. This is only the tip of the iceberg. It can be said that the embedded system is completely integrated into us and affects our work and life all the time.
Embedded system, since it is a computer system, it is certainly inseparable from the hardware and software. A typical architecture of an embedded system is as follows.
The most important thing here is the embedded operating system and the embedded microprocessor.
From the hardware point of view, an embedded system is a multi-module system with a processor (CPU) as the core and relying on a bus (Bus) for connection.
In fact, it is not difficult to see that it is the same way as a personal PC. A microcontroller is clearly defined as a computer system on a single chip (chip). And although different microcontrollers have different configurations, different performance, different manufacturers, and even different instruction sets and development methods, but they are all complete computer systems on a single chip, this definition is not wrong. Embedded is an unclear definition, and there is no very clear definition of the word “embedded”. He is also not a definite “thing” name, like microcontroller.
Is a microcontroller embedded?
So is a microcontroller embedded or not? Simply put: yes. Because many embedded products are embedded in the computer system is a microcontroller, for example, the control board embedded in the air conditioner is actually a microcontroller at its core. In fact, most of the embedded computer systems in home appliances are microcontrollers. Because the microcontroller is simple and cheap enough and enough, so the use of a single-chip computer is the most cost-effective and suitable. And now the largest number of single-chip computer shipments in the field of home appliances, of course, the future of IOT class applications will become more and more, will become a large incremental market for single-chip computer.
Embedded in the broad and narrow sense
The concept of embedded is actually very generalized, and people who speak the word embedded now may not want to express the same meaning. The concept of embedded we talked about above is the original definition of embedded, which is called embedded in a broad sense. And the narrow sense of embedded, in fact, is “embedded linux system” for short. This narrow sense of embedded initially refers to the embedded computer system running the linux system. Later, it also includes the computer running other embedded systems (such as WinCE, Vxworks, Android, etc.) of the same level as linux. After reading the above introduction you will know whether microcontroller is embedded or not, in fact, the connection between the two is very deep, in short, whether you are ready to learn embedded or microcontroller, you have to think about it before making a decision.
Embedded and microcontroller difference
Speaking of which, let’s see, what is the difference between embedded and microcontroller. From the introduction of the previous article, embedded system is a big category, microcontroller is one of the important subcategories. An embedded system is like a complete computer, while a microcontroller is more like a computer without peripherals. In the past, microcontrollers did not include much, and the hardware difference between the two was more obvious. However, with the rapid advancement of semiconductor technology, various hardware functions can now be made into a microcontroller. Therefore, the hardware difference between embedded system and microcontroller is getting smaller and smaller, and the dividing line is getting blurred. Thus, people tend to make the distinction in software. From the software, the industry often does not bring MMU (memory management unit, memory management unit) in the chip and thus does not support virtual address, can only run bare or RTOS (real-time operating system, such as ucos, Huawei LiteOS, RT-Thread, freertos, etc.) system, called a microcontroller (such as STM32, NXP LPC series, NXP imxRT1052 series, etc.). At the same time, the chip comes with MMU can support virtual address, can run Linux, Vxworks, WinCE, Android and other “advanced” operating system system, called embedded. At some point, the microcontroller itself is powerful enough to be used as an embedded system. It is cheaper and relatively less difficult to develop and maintain, especially for some more targeted applications. Embedded systems, on the other hand, are theoretically more powerful and more widely used, but are more complex and difficult to develop.
Why learn embedded and microcontroller
Today I also just give you a brief introduction to microcontroller and embedded and their relationship and differences, although embedded systems have been more than 30 years of history, but in fact has been hidden in the background, since the Internet of Things rose to the national strategy, embedded systems also gradually from the background to the foreground. Embedded and microcontroller is not pure “hardware” class direction. If you want to learn embedded and microcontroller, only know digital circuit and microcomputer interface such hardware knowledge is not enough, you need to learn more, is assembly, C/C++ language, data structure and algorithm knowledge. Having the ability to combine hardware and software is far more valuable than simply mastering a certain program development language. Secondly, embedded and microcontroller have a wide range of application scenarios, and there are project needs and talent demands in various fields. And our country is now vigorously developing chip industry, which will also drive the employment of embedded talents and improve the treatment. With the deepening of 5G construction, the whole society is changing to the direction of “Internet of Everything”. IOT technology will also usher in unprecedented historical opportunities. Embedded and microcontroller technology is an important part of IoT technology, and will also enter the era of rapid development. The more difficult the technology, the more painful the process, the more conducive to building a competitive barrier. Many students in the university are keen to learn various programming languages, often neglecting this piece, it can be said that in the embedded development of this piece of talent our country is still relatively short. Therefore, I think it is very worthwhile to invest time to learn the skills of embedded development.
