What exactly is embedded? What is a single-chip microcomputer?
9 min read
Anyone who works in computer or electronic information related fields must have heard of embedded and single- chip microcomputers , right?
Many people should know that these two terms are very closely related to hardware systems. As soon as you hear them, it’s easy to think of a circuit board full of chips and pins: lcd display module
However, if you want to ask what is an embedded, what is a single-chip microcomputer, and what is the difference between them, I believe most people can’t explain it clearly.
Today, Xiaozaojun will give you an introduction to popular science and reveal the answers to the above questions. At the same time, I will also introduce to you what the 51 and STM32 that we often hear about are.
what is embedded
First, let’s take a look at what is embedded.
Embedded, generally refers to the embedded system, English called: embedded system. Embedded development is actually the development of embedded systems.
The IEEE (Institute of Electrical and Electronics Engineers) defines an embedded system as: “A device used to control, monitor, or assist in the operation of machines and equipment.”
The domestic academic definition is more specific and easier to understand:
Embedded system is application-centric, based on computer technology, software and hardware can be tailored, and is suitable for special computer systems with strict requirements on function, reliability, cost, size, and power consumption.
Taking the application as the center, it shows that the embedded system has a clear practical purpose. Based on computer technology, it means that it is actually a special kind of computer. Software and hardware can be tailored, indicating that it has strong flexibility and customizability.
Special purpose computer system, “special purpose” corresponds to “general purpose”. Our commonly used personal PCs, laptops, and data center servers can be used for a variety of purposes, which is a “general-purpose computer system”.
What “special purpose” directions are embedded systems used for?
An example is as follows:
- Personal communication and entertainment systems: mobile phones, digital cameras, music players, wearable electronics, PSP game consoles
- Home appliances: digital TV, sweeping robots, smart home appliances
- Office automation: printers, copiers, fax machines
- Medical electronic products: biochemical analyzer, blood analyzer, CT
- Network communication products: communication switching equipment, network equipment (switches, routers, network security)
- Automotive electronics: engine control, safety systems, car navigation and entertainment systems
- Industrial control products: industrial computer, interactive terminal (POS, ATM), security monitoring, data acquisition and transmission, instrumentation
- Military and aerospace products: UAVs, radars, combat robots
In these fields, embedded systems are used. This is just the tip of the iceberg.
It can be said that the embedded system completely surrounds us and affects our work and life all the time.
Embedded system, since it is a computer system, must be inseparable from hardware and software.
A typical architecture of an embedded system is as follows:
Note that the most important is the embedded operating system and embedded microprocessor.
From a hardware point of view, an embedded system is a multi-module system with a processor (CPU) as the core and connected by a bus (Bus):
The following picture is a physical example of an embedded system:
The upper left corner in the middle, S3C2440, is the CPU, the middle is the RAM, and then there are ROM, network card, serial port, power supply and so on. It can be seen that although the embedded system sparrow is small, it has all the internal organs.
What is a single-chip microcomputer
The core of the embedded system is the embedded processor. Embedded processors are generally divided into the following typical types:
- Embedded microcontroller MCU (Micro Control Unit)
MCU integrates ROM/RAM, bus logic, timer/counter, watchdog, I/O, serial port, A/D, D/A, FLASH, etc. Typical representatives are 8051, 8096, C8051F, etc.
- Embedded DSP processor (Digital Signal Processor)
The DSP processor is specially used for signal processing, and the system structure and instruction algorithm are specially designed. Widely used in digital filtering, FFT, spectrum analysis. A typical representative is the TMS320C2000/C5000 series of TI (Texas Instruments).
- Embedded microprocessor MPU (Micro Processor Unit)
MPU evolved from a general-purpose processor with high performance and rich peripheral component interfaces. Typical representatives are AM186/88, 386EX, SC-400, PowerPC, MIPS, ARM series, etc.
In addition, there are embedded system-on-chip SoC (System on Chip) and programmable system-on-chip SoPC (System on a Programmable Chip) .
Our single-chip microcomputer belongs to the first type mentioned above – MCU (embedded microcontroller).
Let’s describe it in detail.
Single chip microcomputer, also known as single-chip microcontroller, is called Single-Chip Microcomputer in English.
It is actually a kind of integrated circuit chip. It uses VLSI technology to put functions such as CPU, RAM, ROM, I/O and interrupt system, timer/counter, etc., into a piece of silicon chip and turn it into an ultra-small computer.
So, isn’t the single-chip microcomputer an embedded system? Don’t worry, let’s look down.
“Microcontroller” is actually an ancient name. In the past, the semiconductor process technology was immature, and different functions could not be integrated into one chip, so there would be multiple chips. Now semiconductor technology has been very developed, so there is no multi-chip computer. However, the name of “MCU” has been extended to this day.
Many college teachers like to emphasize that the single-chip surname is “Single”. In addition to referring to the single-chip microcomputer as just a silicon chip , it also refers to the single-function single-chip microcomputer. It is a single module that completes functions such as operation, logic control, and communication. No matter how powerful it is, the function is still single.
The single-chip microcomputer technology was born in the late 1970s. In the early days, it was 4-bit, and later developed into 8-bit, 16-bit, and 32-bit. It really rose in the 8-bit era. The 8-bit microcontroller has strong functions and is widely used in industrial control, instrumentation, home appliances, automobiles and other fields.
When we study microcontrollers, we often hear two words – 51 microcontroller , STM32 . Let me explain what they are.
51 single-chip microcomputer, in fact, is the collective name of a series of single-chip microcomputers. This series of microcontrollers is compatible with Intel 8031 instruction system. Their ancestor is Intel’s 8004 microcontroller.
Note that the 51 MCUs are not all Intel products. Including ATMEL (Aidemel), Philips (Philips), Winbond, Dallas (Dallas), Siemens (Siemens), STC (China-made Hongjing) and other companies, there are also many products belonging to the 51 MCU series.
The 51 single-chip microcomputer has been the most mainstream and widely used single-chip microcomputer on the market for a long time, occupying a large market share.
The 51 single-chip microcomputer actually has no technical advantages at present, and it is a very old technology. The reason why its vitality is tenacious, in addition to its popularity, is that Intel has completely opened up the copyright of the 51 core.
Therefore, no matter any unit or individual, you can use the 51 MCU without any scruples, without paying, and without worrying about copyright risks.
In addition, 51 single-chip microcomputer has a solid stock foundation and mass foundation. Many old projects use 51 single-chip microcomputers. Due to cost considerations, sometimes the technology of 51 single-chip microcomputers can only be continued to be upgraded. Moreover, many engineers of the older generation are proficient in 51 single-chip development technology. Therefore, the vitality of the 51 microcontroller can continue.
Let’s look at STM32 again.
STM32 is a general-purpose microcontroller based on the ARM Cortex-M core introduced by STMicroelectronics .
STMicroelectronics is one of the world’s largest semiconductor companies. It was established in June 1987 by the merger of Italy’s SGS Microelectronics and France’s Thomson Semiconductor. In May 1998, SGS-THOMSON Microelectronics changed the company name to STMicroelectronics Limited.
ARM company Xiaozaojun introduced it to you before. It is currently one of the most powerful companies in chip design in the world. It has risen by taking advantage of the rapid development of mobile phone chips and occupies a huge share of the Internet of Things market.
In the field of microcontrollers, ARM’s Cortex-M core has an overwhelming advantage and has become the absolute mainstream. Many semiconductor companies have abandoned their original architecture and switched to ARM-based microcontrollers.
The hardware configuration of STM32 can meet most of the development needs of the Internet of Things. The development tools and related documents are complete, and it has become the first choice for single-chip learning.
The difference between embedded and single chip microcomputer
Having said that, let’s take a look at what is the difference between embedded and microcontroller.
From the previous introduction, the embedded system is a large category, and the single-chip microcomputer 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, the single-chip microcomputer did not include many things, and the hardware difference between the two was more obvious. However, with the rapid advancement of semiconductor technology, various hardware functions can now be incorporated into single-chip microcomputers. Therefore, the hardware distinction between embedded systems and single-chip microcomputers is getting smaller and smaller, and the dividing line is becoming more and more blurred.
Therefore, people tend to differentiate in software.
From the software point of view, the industry often does not have an MMU (memory management unit, memory management unit) in the chip so that it does not support virtual addresses, and can only run streaking or run RTOS (real-time operating system, such as ucos, Huawei LiteOS, RT-Thread, freertos etc.) system, called microcontroller (such as STM32, NXP LPC series, NXP imxRT1052 series, etc.). And the chip’s built-in MMU can support virtual addresses, and can run “advanced” operating systems such as Linux, Vxworks, WinCE, and Android. The system is called embedded.
At some point, the microcontroller itself is powerful enough to be used as an embedded system. Its cost is lower, and it is relatively less difficult to develop and maintain, especially for some more targeted applications. The embedded system has stronger performance in theory and is more widely used, but it has high complexity and is difficult to develop.
The learning value of embedded and single chip microcomputer
Finally, let’s talk about the learning value of embedded and single-chip microcomputer. Is it necessary to learn embedded and single-chip microcomputer?
In recent years, there is a saying that has been widely spread, that is – “software is king”. It is generally believed that the value of software knowledge is far greater than that of hardware, and learning software and engaging in software direction will make it easier to find a job, and find a higher-paying and more promising job.
Embedded and single-chip microcomputers are often classified as “hardware” and are “disgusted” by people. In addition, embedded and single-chip microcomputers are difficult to learn, and the learning cycle is very long, which requires a long “torture”, so more and more people give up this road.
Xiaozaojun thinks this idea is incorrect.
First, embedded and microcontrollers are not purely “hardware” categories. As I said earlier, they are a tight combination of software and hardware.
If you want to learn embedded and single-chip microcomputers, it is not enough to only know hardware knowledge such as digital circuits and microcomputer interfaces. What you need to learn is assembly, C/C++ language, data structure and algorithm knowledge.
Having the ability to combine software and hardware is far more valuable than simply mastering a certain programming language.
Secondly, embedded and single-chip microcomputers have a wide range of application scenarios, and there are project needs and talent needs in various fields.
According to statistics from authoritative departments, there is currently a shortage of 500,000 embedded talents in our country every year. Embedded software development, in particular, is one of the hottest and most sought-after careers in the coming years. A senior embedded engineer with 10 years of work experience can earn an annual salary of around 300,000-500,000 yuan.
Moreover, our country is now vigorously developing the chip industry, which will also drive the employment of embedded talents and improve their treatment.
With the full launch of 5G, the whole society is developing in the direction of “Internet of Everything”. The Internet of Things technology will also usher in unprecedented historical opportunities. Embedded and single-chip technology is an important part of the Internet of Things technology, and will also enter the fast lane of development.
Therefore, although the learning process will be difficult, Xiaozaojun still recommends aspiring young people to pay attention to this track. The more difficult the technology and the more difficult the process, the more conducive to building competition barriers. In the later stage, personal value can be further reflected.
