Single chip microcomputer, single chip microcomputer. Overall, he is a chip. But he is a special chip because he does not implement separate logic functions. He integrated an integrated computer system onto the chip. This computer system includes an arithmetic unit, a controller, a memory, an input device, and an output device.
In fact, the learning of single-chip microcomputers is not too different from the learning of computers. Includes arithmetic, controller, memory, and learning of input and output devices.
Operator
The arithmetic unit is composed of arithmetic components - arithmetic logic unit (alu), accumulator, calculator and other components.
Controller
The difficulty in learning lies in the operations related to the instructions. The controller consists of a program counter, an instruction register, an instruction decoder, a timing generator and an operation controller.
The development process of the microcontroller:The development process mentioned here is not from the task analysis mentioned in the general book. We assume that the hardware has been designed and manufactured. The following is the work of writing software. Before writing software, first determine some constants and addresses. In fact, these constants and addresses have been directly or indirectly determined during the design phase. For example, when a device's connection is designed, its address is determined. When the function of the device is determined, its control word is determined. Then use a text editor (such as EDIT, CCED, etc.) to write the software, after writing, compile the source program file with the compiler, check the error, until there is no syntax error, in addition to the very simple program, the general application of the simulation machine to the software Debug until the program runs correctly. Once the operation is correct, you can write a slice (cure the program in EPROM). After the source program is compiled, an object file with the extension HEX is generated. The general programmer can recognize the file in this format, and can write the file by simply loading the file.
Development language choiceAt present, many people do not recognize assembly language. It can be said that mastering programming with C language MCU is very important and can greatly improve the efficiency of development. However, beginners may not understand the assembly language of the single-chip microcomputer, but must understand the specific performance and characteristics of the single-chip microcomputer, otherwise it is relatively deadly in the field of single-chip microcomputer. If you do not consider the hardware resources of the microcontroller, use C to program in KEIL, the result can only be a problem can not be solved! To be sure, the best C-language MCU engineers are programmers who come out of the compilation, because the C language of the MCU is a high-level language, but it is different from VC++ on a desktop PC. The hardware resources of the MCU are not very powerful. Different from the high-level languages ​​such as VC and VB, we write programs on the desktop PC. After all, the hardware of the desktop computer is very powerful, so we can ignore the problem of hardware resources. There is also a C language programming in MCU programming, which is convenient for people to read, but the execution efficiency is 10% to 20% lower than the assembly language, so the language used to write the program depends on the specific occasion. In general, MCU programming requires flexible use of assembly language and C language, so that the powerful functions of the MCU are presented to the user with the highest efficiency.
Commonly used microcontroller typesSTC microcontroller
STC's MCU is mainly based on the 8051 core. It is a new generation of enhanced MCU. The instruction code is fully compatible with the traditional 8051. It is 8~12 times faster, with ADC, 4-way PWM, dual serial port, global unique ID number, good encryption. Strong anti-interference.
PIC microcontroller:
It is a product of MICROCHIP company. Its outstanding features are small size, low power consumption, reduced instruction set, good anti-interference, high reliability, strong analog interface, good code confidentiality, and most chips have compatible. FLASH program memory chip.
EMC microcontroller:
It is a product of Taiwan Yilong Company. A large part of it is compatible with PIC 8-bit MCU, and the resources of compatible products are relatively more than PIC. The price is cheap, there are many series available, but the anti-interference is poor.
ATMEL MCU (51 MCU):
ATMEl's 8-bit MCU has two series of AT89 and AT90. AT89 series is 8-bit Flash MCU, compatible with 8051 series MCU, static clock mode; AT90 series MCU is enhanced RISC structure, full static working mode, internal load online The microcontroller for programming Flash is also called AVR microcontroller.
PHLIPIS 51LPC series MCU (51 MCU):
PHILIPS's single-chip microcomputer is based on the 80C51 core microcontroller, embedded with power-down detection, analog and on-chip RC oscillator, which makes 51LPC meet many aspects in high-integration, low-cost, low-power application design. Performance requirements.
HOLTEK microcontroller:
Taiwan's Shengyang Semiconductor's single-chip microcomputers are cheaper and have more types, but they are less resistant to interference and are suitable for consumer products.
TI company microcontroller (51 single chip):
Texas Instruments offers two series of general-purpose MCUs, TMS370 and MSP430. The TMS370 series MCUs are 8-bit CMOS MCUs with multiple memory modes and multiple peripheral interface modes for complex real-time control applications. MSP430 series MCUs are ultra-low A 16-bit low-power microcontroller with high power consumption and high functional integration is especially suitable for applications requiring low power consumption.
Song Han MCU (SONIX):
It is a single chip of Taiwan Songhan Company, most of which are 8-bit machines. Some of them are compatible with PIC 8-bit MCUs. The price is cheap, the system clock is divided by more options, and there is internal noise filtering of the internal vibration of the PMW ADC. Disadvantages RAM space is too small, anti-interference is better.
Samsung MCU
Samsung MCU has KS51 and KS57 series 4-bit MCU, KS86 and KS88 series 8-bit MCU, KS17 series 16-bit MCU and KS32 series 32-bit MCU, Samsung also produces ARM MCU for ARM, common S344b0 and so on. Samsung MCU is an OTP-type ISP in-chip programming function.
SST microcontroller
The SST89 series of single-chip microcomputers introduced by American SST Company are standard 51 series single-chip microcomputers, including SST89E/V52RD2, SST89E/V54RD2, SST89E/V58RD2, SST89E/V554RC, SST89E/V564RD and so on. It is compatible with the 8052 series microcontrollers. Provide system online programming (ISP function). The internal flash erasing times are more than 10,000 times, and the program save time can reach 100 years.
There are still many excellent MCU manufacturers that do not collect here. Each enterprise has its own characteristics. Everyone chooses the MCU according to their needs. Under the premise of fully realizing the function, the pursuit of low price is certainly not the best. Actually, choose MCU. It is inseparable from the developer's application habits and development experience.
MCU and embedded system:Embedded systems are derived from embedded applications of computers. Early embedded systems were various electronic systems that were modified into general-purpose computers and embedded in the object system, such as ship autopilots, turbine monitoring systems, and so on. The embedded system is firstly a computer system. Secondly, it is embedded in the object system, and realizes the data acquisition, processing, status display, output control and other functions required by the object in the object system. Because it is embedded in the object system, the embedded system A computer does not have the independent form and function of a computer. The MCU is completely designed according to the requirements of the embedded system, so the MCU is the most typical embedded system. The early MCUs were just computer-on-chip integrations designed according to embedded application technology requirements, hence the name MCU. Subsequently, the MCU has continuously enhanced its control functions and peripheral interface functions to meet the requirements of embedded applications, especially the prominent control functions. Therefore, the MCU has been called the Microcontroller Unit (MCU).
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