4 major misunderstandings in learning 51 single-chip microcomputers

    51 refers to the MCS-51 series of single-chip microcomputers and the CICS instruction set. Developed by Intel, its structure adds instructions such as multiplication (MUL), division (DIV), subtraction (SUBB), comparison (CMP), 16-bit data pointers, Boolean algebra operations, as well as serial communication capabilities and 5 interrupt sources. It has 128 RAM units and 4K ROM. Its representative model is the A series of ATMEL, which is widely used in industry. At present, the domestic 51 single-chip microcomputer market is mainly for domestic products STC series, which are known to be stable and cheap.


    Myth 1: 51 single-chip microcomputer is the basis of learning

    . The sentence "51 single-chip microcomputer is the basis of learning" itself is not wrong. When I was an undergraduate, it was undoubtedly the basis of learning. After all, there were no more advanced microcontrollers available at that time, and there were no more advanced textbooks for reference in China. The level of teachers was also uneven. The 51 microcontroller met such needs. Not only did it have a large number of mature textbooks and examples, but the actual projects at work at that time were also mainly 51 microcontrollers. Therefore, the 51 microcontroller naturally became the basis of learning at that time. You should know that when I was an undergraduate in 2004, it was 10 years ago. According to Moore, the industry is updated every 18 months, and the technology 10 years ago has now been updated 6 generations - this is indeed the case.

    At present, various tutorials for 32-bit Crtex-M series microcontrollers have been popularized, and the difficulty of learning has been continuously reduced. For the company's F series microcontrollers, STMicroelectronics gave away a large number of core boards in the early stage of product promotion. The free core board not only has the popular 32-bit Cortex-M series microcontroller, but also integrates an online debugger on the board. The CD or link that comes with it provides a large number of sample source codes. We only need to install the development environment to directly compile and download debugging. At this point, it is definitely out of date to say that the 51 MCU is the basis of learning.

    Myth 2: The 51 MCU can learn operations.

    The 51 MCU can learn register operations, which is beyond doubt. Let's analyze the deeper reasons. In the programming environment of the MSC-51 MCU, assembly language was initially used as the main programming language. You should know that assembly language is used to directly operate registers, and assembly language cannot do the function calls and calls of C language. If the 51 MCU is said to have the advantage of operating registers, I think it should be said that the 51 MCU operating registers is a kind of helplessness, and it is a multiple-choice question with only one option. Can't

    our current Cortex-M series MCU learn registers? Obviously not. In, the hardware operation mode is the operation of registers, but its implementation can be different. The C language library function package provided by each microprocessor is actually the encapsulation of the instructions for operating registers in the C language environment. Here we use the official ST library function to give an example:

    void USART_Init (USART1, * USART_InitStruct); // Implement the initialization of 1, simple and clear, no comments required.

    I would also like to give an example here to illustrate the steps of register operation, but the operation of registers is too complicated, and I don't want to waste time to sort it out. The

    easy-to-understand C language, the easy-to-port C language and the corresponding hardware platform can complete the hardware operation. With a simple and convenient way, why do we still have to consider the cumbersome and complex assembly language and register operation?

    Myth 3: The cost of 51 microcontrollers

    Low cost is the main factor affecting the application. The main consideration for project establishment is cost, and the main consideration for sales pricing is cost. Only low-cost solutions will have an advantage in the market. However, is the 51 microcontroller really the lowest cost? Not really. Now according to the functional division, the cost of some Cortex-m0 series can also be 3 yuan. Its performance is several times that of the 51 microcontroller, and it is easier to develop and maintain.

    There is another cost: the cost of development difficulty. 51 single-chip microcomputers do not support online debugging. Some problems are not found in the early stage of programming. They will only appear after connecting to the hardware, such as the delay often used in control operations. At this time, the huge advantage of online debugging is reflected. It can easily view the current state of the microprocessor, making the analysis of the problem simple and transparent. Thus, it effectively reduces the difficulty of development, shortens the development cycle, and saves development funds.

    Myth 4:

    Is it easy to get started with 51 single-chip microcomputers? I have reservations about this view. To get started with 51 single-chip microcomputers, I must not only be familiar with the peripherals of this single-chip microcomputer, but also fully understand the meaning of a certain bit of the register. For the clock, the configuration must be well known. This will undoubtedly increase my learning difficulty and familiarity cycle. If we use the library function of a 32-bit single-chip microcomputer, we only need to have the knowledge of C language, understand the API function, and directly look at the meaning of the annotated register. There is no need to understand its underlying hardware implementation, let alone the meaning of a certain specified bit of a register. In this way, my workload is reduced, thereby reducing the difficulty of development. Which one do you think is easier to get started with, the 51 MCU or the 32-bit Cortex core microprocessor?

    Learning is very boring and challenging. Because it is directly connected to the actual hardware, we must not only consider the correctness of the programming, but also the reliability of the hardware. At this time, simple and efficient software writing will indirectly reduce our development difficulty and risk. The 51 MCU is already a thing of the past, and looking forward is the development. It's time to say goodbye to the 51 MCU!