As far as I know, there were 4-bit microcontrollers in the early days. Anyway, I never used a 4-bit microcontroller, and later it developed to 8-bit, 16-bit, 32-bit. At present, the most commonly used is 8 digits.
Just like a computer.
Complex instruction set and reduced instruction set.
Von Neumann structure.
Commonly used 5 1, AVR, ARM
Now mobile phones and everything are ARM.
There are some others.
Such as PIC, MSP430 and so on
What types of microcontrollers are there? Microcontroller is a simple chip computer, which is slower than computer CPU, low in power consumption, convenient to use, and does not need a fan to meet general purposes.
1, 8-bit 805 1 core: 89c51/89c52/89c53/89c54/89c58; There is also a new suffix 89C5 1RD, RC series with ISP.
2 16 bit series: AVR microcontroller of atmel, MSP430 series of TI and STM32 series of ST.
3. 32-bit ARM7 and ARM9 series: 920T and 926EJ-S, such as Samsung's S3C2410/2440; STM32W 103/ 107 series of ST, etc.
4. There are many cores close to the ARM9 series.
What are the models of mcs-5 1 microcontrollers? MCS-5 1 series microcontrollers mainly include 803 1, 805 1, 875 1 and other general products, and their main functions are as follows: 8-bit CPU byte program storage (ROM).
128 byte data storage (RAM)
32 input/output port lines
1 1 1 instructions, most of which are unit tuple instructions.
2 1 special register
2 programmable timers/counters
5 interrupt sources, 2 priorities
Full duplex serial communication port
The addressing space of the external data memory is 64kB.
The addressing space of the external program memory is 64kB.
Logical operation bit addressing function
Dual in-line 40-pin DIP package and +5V single power supply.
What are the models and series of microcontroller IC? Under normal circumstances, there is an IC before a program, so there is no way to choose a microcontroller according to the program. It depends on what environment and model of microcontroller your program is written in, otherwise the program will not be downloaded, and even if it is downloaded, it may not run.
What types of microcontrollers are there? They are divided into 8 bits, 16 bits and 32 bits according to data bits.
By manufacturer, atmel, nxp, st, ti, intel, Winbond, stc, Philips, moto roller and so on.
According to the processing speed, it is divided into low speed and high speed.
There are other sub-methods, and the above example is only a part!
What types of microcontrollers are there? A complete computer system integrated on a chip. Although most of its functions are integrated on a small chip, it has most of the components needed by a complete computer: CPU, memory, internal and external bus systems, and most of them will have external memory at present. At the same time, peripheral devices such as communication interface, timer and real-time clock are integrated. Nowadays, the most powerful microcontroller system can even integrate sound, video, network and complex input and output systems on one chip.
Microcontrollers are also called microcontrollers because they were first used in the field of industrial control. Microcontroller is developed from special processor, and there is only CPU in the chip. The earliest design concept was to integrate a large number of peripheral devices and CPU into one chip, making the computer system smaller and easier to integrate into complex and strict control equipment. Intel's Z80 is the first processor designed according to this idea. Since then, the development of microcontrollers and dedicated processors has gone their separate ways.
Early microcontrollers were all 8-bit or 4-bit. The most successful is INTEL's 803 1, which has won great praise because of its simplicity, reliability and good performance. Since then, MCS5 1 series microcontroller system has been developed on 803 1. The single chip microcomputer system based on this system is still widely used. With the improvement of industrial control requirements, 16-bit microcontroller began to appear, but it has not been widely used because of its unsatisfactory cost performance. With the great development of consumer electronic products after 1990s, the microcontroller technology has been greatly improved. With the wide application of INTEL i960 series, especially the later ARM series, 32-bit microcontroller quickly replaced the high-order position of 16-bit microcontroller and entered the mainstream market. The efficiency of the traditional 8-bit microcontroller has also been improved rapidly, and the processing capacity has been improved by hundreds of times compared with that in the 1980s. At present, the main frequency of the high-end 32-bit microcontroller has exceeded 300MHz, and the efficiency is catching up with the special processor in the mid-1990s. However, the ex-factory price of ordinary models has been reduced to 1 USD, and the top-end models are only1USD. Contemporary microcontroller systems are no longer only developed and used in bare metal environment, and a large number of dedicated embedded operating systems are widely used in all series of microcontrollers. In the high-order microcontroller, which is the core processing of palmtop computers and mobile phones, special Windows and Linux operating systems can even be directly used.
Microcontrollers are more suitable for embedded systems than dedicated processors, so they get the most applications. In fact, microcontrollers are the largest number of computers in the world. Almost all electronic and mechanical products used in modern human life will be integrated with microcontrollers. Mobile phones, telephones, calculators, household appliances, electronic toys, palmtop computers and mice are all equipped with 1-2 microcontrollers. There will be many microcontrollers in personal computers. Cars are generally equipped with more than 40 microcontrollers, and even hundreds of microcontrollers may work at the same time in complex industrial control systems! The number of microcontrollers not only far exceeds the sum of PC and other calculations, but also exceeds the number of human beings.
Introduction of microcontroller
[Edit this paragraph]
Microcontroller, also known as single-chip microcontroller, is not a chip that completes some logical function, but integrates a computer system into a chip. To sum up: the chip becomes a computer. It is small in size, light in weight and cheap, which provides convenient conditions for learning, application and development. At the same time, learning to use single chip microcomputer is the best choice to understand the principle and structure of computer.
Microcontrollers also use modules with similar functions to computers, such as CPU, memory, parallel bus and storage devices with the same functions as hard disks. The difference is that the performance of these components is much weaker than that of our computer, but the price is also low, generally not more than 10 yuan ... It is enough to do some uncomplicated work such as controlling electrical appliances. We now use automatic drum washing machine, exhaust hood, VCD and other household appliances can see it! ..... is mainly used as the core component of the control part.
It is an online real-time control computer. Online control is field control, which requires strong anti-interference ability and low cost, which is also the main difference from offline computers (such as home PC).
The microcontroller is programmable and can be modified. Different functions, especially some special and unique functions, are realized by different programs, which other devices need to make great efforts to do, while other devices are difficult to do. If a function that is not very complicated is solved by pure hardware such as 74 series developed by the United States in the 1950s or CD4000 series in the 1960s, the circuit must be a large PCB! But if you use a series of microcontrollers that were successfully put on the market in the 1970s, the result will be very different! Just because the single chip microcomputer can realize high wisdom, high efficiency and high reliability through the program you wrote!
Because microcontroller is sensitive to cost, the dominant software at present is the lowest assembly language, which is the lowest language except binary machine code. If it's so low-level, why use it? Many advanced languages have reached the level of visual programming. Why not use them? The reason is very simple, that is, the microcontroller does not have a CPU like a home computer, nor does it have a mass storage device like a hard disk. Even if there is only one button, a small program written in a visual high-level language will reach the size of tens of K! It's nothing for the hard disk of home PC, but it's unacceptable for microcontroller. Microcontrollers must have a high utilization rate of hardware resources, so assembly is still widely used although it is primitive. Similarly, if the operating system and application software on the supercomputer are executed on the home PC, the home PC can't bear it.
It can be said that the 20th century spanned three "electricity" eras, namely, the electrical era, the electronic era and the computer era. However, this kind of computer usually refers to a personal computer, or PC for short. It consists of a host, a keyboard, a display, etc. There is another kind of computer that most people are not familiar with. This kind of computer is a microcontroller (also called microcontroller) that endows all kinds of machines with wisdom. As the name implies, the smallest system of this computer can complete simple operation and control with only one integrated circuit. Because of its small size, it is usually hidden in the "belly" of the controlled machine. It acts like a human brain in the whole device. If something goes wrong with it, the whole equipment will be paralyzed. Now, this microcontroller has been widely used, such as intelligent instruments, real-time industrial control, communication equipment, navigation systems, household appliances and so on. Once the microcontroller is used in various products, the product can be upgraded, and the adjective "smart" is often used before the product name, such as smart washing machine. At present, the products made by technicians or other amateur electronic developers in some factories are either too complicated in circuit or too simple in function and easy to be copied. The reason may be that the product does not use microcontroller or other programmable logic devices.
Application field of microcontroller
[Edit this paragraph]
At present, microcontrollers have penetrated into every field of our lives, and it is almost difficult to find out which field has no traces of microcontrollers. Missile navigation device, control of various instruments on the plane, computer network communication and data transmission, real-time control and data processing of industrial automation process, various intelligent IC cards widely used, safety guarantee system of civilian luxury cars, control of video recorders, cameras, automatic washing machines, program-controlled toys, electronic pets, etc. , these are inseparable from the microcontroller. Not to mention robots, intelligent instruments and medical devices in the field of automatic control. Therefore, the research, development and application of microcontroller will bring up a group of scientists and engineers in computer application and intelligent control.
Microcontrollers are widely used in the fields of instruments, household appliances, medical instruments, aerospace, intelligent management of special equipment and process control, which can be roughly divided into the following categories:
The Application of 1. in Intelligent Instruments
Microcontrollers have the advantages of small size, low power consumption, strong control function, flexible expansion kit, miniaturization and convenient use, and are widely used in instruments and meters. Combined with different types of sensors, they can measure physical quantities such as voltage, power, frequency, humidity, temperature, flow, speed, thickness, angle, length, hardness, elements and pressure. Using microcontroller to control the instrument is digital, intelligent and miniaturized, and its function is more powerful than using electronic or digital circuits. Such as precision measuring equipment (power meter, oscilloscope, various analyzers).
2. Application in industrial control
Microcontrollers can be used to form various control systems and data acquisition systems. For example, intelligent management of factory assembly lines, intelligent control of elevators, various alarm systems and computer networking form a secondary control system.
3. Application in household appliances
It can be said that the current household appliances are basically controlled by microcontrollers, from rice cookers, washing machines, refrigerators, air conditioners, color TVs and other audio-visual equipment to electronic scales.
4. Application in computer network and communication field.
Modern microcontrollers generally have communication interfaces, which can communicate with computers conveniently, providing excellent material conditions for the application between computer networks and communication equipment. At present, the communication equipment has basically realized the intelligent control of the microcontroller, from mobile phones, telephones, small program-controlled exchanges, building automatic communication call systems, train wireless communication, to mobile phones, trunking mobile communication, radios, etc., which can be seen everywhere in daily work.
5. The application of microcontroller in the field of medical devices.
Microcontrollers are also widely used in medical equipment, such as medical ventilators, various analyzers, monitors, ultrasonic diagnostic instruments and sickbed call systems.
In addition, microcontrollers are also widely used in industry and commerce, finance, scientific research, education, national defense and aerospace.
Six important parts of learning should be learned.
[Edit this paragraph]
Six important parts in the study of single chip microcomputer.
1. bus: As we all know, circuits are always composed of elements connected by wires. In analog circuits, connection is not a problem, because devices are generally in serial relationship, and there are not many connections between devices, but the computer circuits are different. It takes the microprocessor as the core, and all devices must be connected to the microprocessor, so the work between devices must be coordinated with each other, so a lot of connections are needed. If there are separate wires between the microprocessor and the device like analog circuits, the number of wires will be amazing. Therefore, the concept of bus is introduced into microprocessor, and all devices share wires. All eight data lines of all devices are connected to eight common lines, which means that all devices are connected in parallel, but this is not enough. If two devices send data at the same time, one is 0 and the other is 1. This situation is not allowed, so it needs to be controlled by the control line to make the equipment work in time sharing, and only one equipment can transmit data at any time (multiple equipment can receive it at the same time). The data line of the equipment is also called data bus, and all the control lines of the equipment are called control bus. There are storage units in the internal or external memory and other devices of the microcontroller, and these storage units can only be used if they are assigned addresses. Of course, the assigned address is also given in the form of electrical signals. Because there are many memory cells, there are also many lines for address allocation, which is called address bus.
2. Information, address and instruction: The reason why these three are put together is that they are all the same in essence-numbers, or a string of' 0' and'1'. In other words, addresses and instructions are also data. Instruction: a number designated by the designer of the microcontroller chip, which has a strict one-to-one correspondence with our commonly used instruction mnemonics and cannot be changed by the developer of the microcontroller. Address: it is the basis for finding internal and external memory cells and input/output ports of the microcontroller. The address value of the internal unit has been specified by the chip designer and cannot be changed. The external unit can be decided by the microcontroller developer, but some address units are necessary (see the execution process of the program for details). Data: This is an object processed by a microprocessor, which is different in various application circuits. Generally speaking, the processed data may have the following situations:
1? Address (such as MOV DPTR, # 1000H), that is, address 1000H, will be sent to DPTR.
2? Mode word or control word (such as MOV·TMOD, #3), 3 is the control word.
3? Constants (such as MOV TH0, # 10H) 10H are timing constants.
4? Actual output value (for example, P 1 is connected with colored lights, if the lights are all on, execute the instruction: MOV P 1, # 0fh, if the lights are all dark, execute the instruction: MOV P 1, #00H), where 0fh and 00H are the actual output values. Another example is the font code for LED, which is also the actual output value.
Knowing the nature of address and instruction, it is not difficult to understand why the program will deviate and execute the data as an instruction.
Third, the use of the second function of P0, P2 and P3: Beginners are often confused about the use of the second function of P0, P2 and P3. They think there should be a switching process, or an instruction, between the second function and the original function. In fact, the second function of each port is completely automatic and does not require instruction conversion. For example, P3.6 and P3.7 are WR and RD signals respectively. When microprocessors are externally connected to RAM or have external I/O ports, they are used as secondary functions and cannot be used as general I/O ports. As long as the microprocessor executes the MOVX instruction, it will send corresponding signals from P3.6 or P3.7 without prior instruction. In fact, "can't be used as a general I/O port" is not "can't" but "won't" use it as a general I/O port. You can arrange a SETB P3.7 instruction in the instruction. When the microcontroller executes this instruction, it will also make P3.7 high, but the user will not do so, because this usually leads to system crash.
4. Program execution process: After the microcontroller is powered on, the value in the program counter (PC) in 805 1 is' 0000', so the program is always executed from the' 0000' unit, which means that the' 0000' unit must exist in the rom of the system, and there must be a storage in the' 0000' unit.
5. Stack: Stack is an area for storing data. This area itself is nothing special, but it is part of the internal RAM. What is special is the way it stores and accesses data, that is, the so-called' first in, last out, last in, first out'. The stack has special data transmission instructions, namely' push' and' pop', and a special unit, namely the stack index SP. SP automatically adds 1 (based on the original value), and automatically subtracts 1 (based on the original value) every time the POP instruction is executed. Since the value in SP can be changed by instruction, the stack can be set in the specified storage unit as long as the value of SP is changed at the beginning of the program. For example, at the beginning of a program, a stack can be set in a cell starting from the memory cell 60H by using the MOSP #5FH instruction. Generally, there is always an instruction to set the stack index at the beginning of the program, because the initial value of SP is 07H at the start, which makes the stack start from 08H, and the area from 08H to 1FH is the second, third and fourth working register areas of 803 1, which will cause data confusion if it is used frequently. When different authors write programs, the initialization stack instructions are not exactly the same, which is the habit of the authors. Setting the stack area does not mean that the area becomes a special memory, but it can still be used as a common memory area, but programmers generally do not use it as a common memory.
6. Development process of microcontroller: The development process mentioned here does not start with task analysis as mentioned in the general book. We assume that the hardware has been designed and manufactured, and the following is the work of writing software. Before writing software, we must first determine some constants and addresses. In fact, these constants and addresses have been determined directly or indirectly in the design stage. For example, when the connection of a device is designed, its address is determined, and when the function of the device is determined, its control word is also determined. Then use a text EDITor (such as edit, CCED, etc. ) to write software. After writing, compile the source file with a compiler and check for errors until there are no grammatical errors. Except for very simple programs, the simulator is generally used to debug the software until the program is executed correctly. After the execution is correct, you can write the program (solidify the program in EPROM). After the source program is compiled, a target file with the extension HEX will be generated. Ordinary programmers can recognize this file format and call this file to write a film. Here, in order to give you an understanding of the whole process, give an example:
Organization 0000H
LJMP start
ORG 040H
Start:
MOV SP, # 5FH build a stack.
Cycle:
Nototherwiseprovided(for) unless otherwise specified.
LJMP cycle; ring
End; end
Microcontroller learning
[Edit this paragraph]
At present, many people don't recognize combinatorial languages. It can be said that it is very important to master the C language programming of single chip microcomputer, which can greatly improve the efficiency of development. But beginners don't need to know the assembly language of microcontroller, but they must know the specific performance and characteristics of microcontroller, otherwise it will be fatal in the field of microcontroller. If you don't consider the hardware resources of the microcontroller, you can only use C programming in KEIL, and the result can only be a problem that cannot be solved! To be sure, the best C language microcontroller engineer is an assembled programmer. Although the C language of microcontroller is a high-level language, it is different from VC++ of desktop computers and personal computers. The hardware resources of microcontroller are not very strong, which is different from writing programs in high-level languages such as VC and VB on desktop PC. After all, the hardware of desktop computers is very strong, so the problem of hardware resources can be ignored.
Taking 805 1 microcontroller as an example, the pins and related functions of microcontroller are explained.
Microcontroller pin diagram
According to the pin function, these 40 pins can be roughly divided into four categories: power supply, clock, control and I/O pins.
1. Power supply:
(1) VCC chip power supply, connected to+5v;
(2)VSS- grounding terminal;
Note: Generally, the pin current of microcontroller is 0v or 5v when tested by multimeter, which is the standard TTL level. However, sometimes when the microcontroller program works, the test result is not this value, but between 0v and 5v. In fact, this is because the multimeter does not respond so quickly, and the pin current of the microcontroller is still kept at 0v or 5v at a certain moment.
Clock: XTAL 1, xtal 2- the inverting input and output of the crystal oscillator circuit.
3. Control line: There are four control lines.
(1) ale/Prog: data latch enable/on-chip EPROM programming pulse.
① ALE function: used to latch the low-order 8-bit address sent by P0 port.
② PROG function: For the chip with built-in EPROM, when programming EPROM, the programming pulse is input to this pin.
⑵ PSEN: external ROM read strobe signal.
⑶ RST/VPD: reset/standby power supply.
① RST (reset) function: reset signal input.
② VPD function: When the V power supply fails, turn on the standby power supply.
⑷ EA/Vpp: internal and external ROM selection/on-chip EPROM programming power supply.
① EA function: internal and external ROM selection terminals.
② Vpp function: In the process of programming EPROM, the programming power Vpp is added to the chip with EPROM inside.
Input-output line
80c51* * has four 8-bit parallel I/O ports: P0, P 1, P2, P3 and ***32 pins.
P3 port also has a second function, which is used for special signal input/output and control signals (belonging to the control bus).
What types of microcontroller chips are there? HOLTEK microcontroller: Shengyang semiconductor microcontroller in Taiwan Province Province, which is cheap and has many kinds, but it has poor anti-interference and is suitable for consumer products.
TI company microcontroller (5 1 microcontroller): Texas Instruments provides two series of general microcontrollers, TMS370 and MSP430. TMS370 series microcontroller is an 8-bit CMOS microcontroller with multiple storage modes and multiple peripheral interface modes, which is suitable for complex real-time control occasions. MSP430 series microcontrollers are 16-bit low-power microcontrollers with ultra-low power consumption and high functional integration, which are especially suitable for occasions requiring low power consumption.
EMC microcontroller: It is a product of Taiwan Province Yilong Company, and a large part of it is compatible with PIC 8-bit microcontroller. The resources of compatible products are relatively more than PIC's, and the price is cheaper. There are many series to choose from, but the anti-interference performance is poor.
ATMEl microcontroller (5 1 microcontroller): ATMEL's 8-bit microcontroller has two series: AT89 and AT90. AT89 series is an 8-bit Flash microcontroller, which is compatible with 805 1 series microcontrollers and has a static clock mode. AT90 series microcontroller, also known as AVR microcontroller, is an enhanced RISC structure, fully static working mode and programmable flash memory on internal load line.
PHLIPIS 5 1PLC Series Microcontroller (5 1 Microcontroller): Based on 80C5 1 core, Philips' microcontroller is embedded with power failure detection, analog and on-chip RC oscillator, which makes 5 1LPC meet various performance requirements in application design with high integration, low cost and low power consumption.
STC microcontroller: The microcontroller of STC Company is mainly based on 805 1 core, which is a new generation of enhanced microcontroller. The instruction code is completely compatible with the traditional 805 1, which is 8~ 12 times faster, with ADC, 4-way PWM, dual serial port, unique ID number in the world, good encryption and strong anti-interference.
PIC MCU: It is a product of MICROCHIP company. Its outstanding features are small size, low power consumption, simplified instruction set, good anti-interference, high reliability, strong analog interface and good code confidentiality. Most chips have their own compatible flash program storage chips.
At present, microcontrollers have penetrated into every field of our lives, and it is almost difficult to find out which field has no traces of microcontrollers. In the field of voice chip, microcontroller and voice chip are integrated into a microcontroller voice chip.
What are the low-power microcontrollers? It is not enough to just focus on the power consumption of the microcontroller. To truly make a low-power product, we must solve it from the design, and pretend to be dead if we can save energy. Don't be fooled by the banner of "lowest power consumption" played by microcontroller manufacturers.
If the MCU learning board is used to learn MCU, it is suggested to start with the 5 1 series.
Development depends on your functional requirements. There are too many kinds of microcontrollers.