A microcontroller is a single chip microcomputer that integrates the main parts of a microcomputer on a chip. The microcontroller was born in the middle of 1970s. After 20 years of development, its cost is becoming lower and its performance is more and more powerful, which makes its application everywhere and in all fields. STM32F446RCT7 microcontrollers are frequently employed in the manufacturing and robotics industries. With the advent of these essential electrical components, the sector has undergone tremendous growth. Easybom is a platform that offer many information about the electronic products, such as microcontrollers, transsitors, semiconductors, and so on.
For example, motor control, bar code reader / scanners, consumer electronics, game devices, telephone, HVAC, building safety and access control, industrial control and automation, and white household appliances (washing machines, microwave ovens). Well, according to wiki, a microcontroller (or MCU for microcontroller unit) is a small computer on a single integrated circuit. In modern terminology, it is similar to, but less sophisticated than, a system on a chip or SoC; an SoC may include a microcontroller as one of its components.
A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Program memory in the form of ferroelectric RAM, NOR flash or OTP ROM is also often included on chip, as well as a small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications consisting of various discrete chips.
Microcontrollers are used in automatically controlled products and devices, such as automobile engine control systems, implantable medical devices, remote controls, office machines, appliances, power tools, toys and other embedded systems. By reducing the size and cost compared to a design that uses a separate microprocessor, memory, and input/output devices, microcontrollers make it economical to digitally control even more devices and processes. Mixed signal microcontrollers are common, integrating analog components needed to control non-digital electronic systems.
- The reliability is good. Because all kinds of functional components of micro controller are integrated on a chip, especially memory is integrated into the chip, the wiring is short, the data are mostly transferred inside the chip, it is not easy to be subjected to external interference, enhance the anti-interference ability, and make the system run more reliably. Therefore, the reliability is obviously superior to the general general CPU system.
- Strong control function. In order to meet the requirements of industrial control, the instruction system of general microcontrollers has a wealth of conditional branching transfer instructions, logical operation and bit processing function of I/O port. In general, the logic control function and running speed of the microcontroller are higher than the CPU of the same level.
- Easy to expand. There are many three buses and parallel, serial input / output pins for extension, and it is easy to form a computer application system of various sizes.
- There is no monitoring program or system management software in the general microcontroller, and the development needs the corresponding simulation system.
The micro controller has been widely used in various fields, such as household appliances, office equipment, measurement and control system, intelligent instrument, communication system and mechanical and electrical industry. With the advent of cheap microcontroller, its application will be more and more extensive.
- Mechatronics products. The combination of micro controller and traditional mechanical products makes the structure of traditional mechanical products simplified, intelligent control, and the human-machine interface is more friendly, forming a new generation of mechanical and electrical integration products. Such as micro controller controlled knitting machine, CNC machine tool and so on.
- Intelligent instrument and instrument. With the transformation of micro controller measurement and control instrument of the original, promoted the instrument to digital, intelligent, multi-functional, integrated and flexible development, make the instrument with automatic range selection, automatic error correction, self diagnosis, data protection and other functions. The measuring, processing and controlling functions of the instrument set, which is composed of the micro controller, endow the measuring instrument and instrument with a new look.
- Measurement and control system. A variety of industrial control systems, adaptive control systems, data acquisition systems, such as automatic control of electroplating production line, are made up of microcontrollers.
- Intelligent computer peripherals. Microcontrollers are used, such as plotter and hard disk drive. The needle printer is controlled by two microcontrollers. The keyboard of a microcomputer is controlled by a microcontroller.
- Intelligent sensor. The combination of the micro controller and the sensor constitutes the intelligent sensor, which can easily realize the nonlinear correction.
- Commonication systems
Microcontroller vs Microprocessor
The differences ofMicrocontroller and microprocessor are mainly concentrated in three aspects：hardware structure, application field and instruction set feature.
The microprocessor is a single-chip CPU, and the microcontroller integrates CPU and other circuits in an integrated circuit chip, forming a complete microcomputer system. In addition to CPU, the microcontroller also includes RAM, ROM, a serial interface, a parallel interface, a timer, and an interrupt scheduling circuit. These are integrated on an integrated circuit. Although the capacity of the RAM on chip is smaller than the ordinary microcomputer system, this does not limit the use of the microcontroller. It can be learned from the back that the application of the microcontroller is very wide.
An important feature of the microcontroller is the built – in interrupt system. As a control oriented device, the microcontroller often responds to external excitation (interruption) in real time. A micro controller must perform a fast context switch and hang one process to execute another process to respond to an “event”. For example, opening the door of a microwave oven is an event, and this event will trigger an interruption in a product based on the microcontroller. Microprocessor can also have strong interrupt function, but usually requires external components to cooperate, and microcontrollers integrate all the circuits necessary to process interrupts on the chip.
Microprocessors are usually used as CPU in a microcomputer system. Its design is aimed at such an application, which is also the advantage of the microprocessor. However, microcontrollers are usually used for control – oriented applications. Its system design seeks miniaturization and reduces the number of components as much as possible. In the past, these applications often need to be implemented with dozens or even hundreds of digital integrated circuits. The use of microcontroller can reduce the number of components.
Only one microcontroller, a few external components and control programs stored in ROM can achieve the same function. Microcontroller is suitable for occasions where input and output devices are controlled by very few components, and microprocessor is suitable for information processing in computer system.
Instruction Set Feature
Because of the different applications, the instruction set of microcontrollers and microprocessors is also different. The instruction set of the microprocessor enhanced the processing function to enable it to have powerful addressing modes and instructions suitable for operating large-scale data. The instructions of a microprocessor can operate on half bytes, bytes, words, or even double words. By using address pointers and address offsets, the microprocessor provides an access mode that can access a large number of data. Self augmented and self subtraction patterns make it easy to access data in byte, word, or double word units. In addition, the microprocessor has other features, such as the failure to use privileged instructions in the user’s program.
The instruction set of the microcontroller is applicable to the input / output control. Many input / output interfaces are single / bit. For example, the electromagnet controls the switch of the motor, and the electromagnet is controlled by a 1 – bit output port. The microcontroller has instructions for setting and clearing units, and also performs other bit oriented operations, such as logical and / or XOR operations on bits, jumping based on flag bits, etc. Few microprocessors have these powerful bit operation capabilities, because when designing microprocessors, designers only consider byte or larger units to operate data.
In terms of device control and monitoring (possibly through a 1 bit interface), the microcontroller has special internal circuits and instructions for input / output, timing and external interrupt priority assignment. In general, microprocessors need to cooperate with additional circuits (serial interface chips, interrupt controllers, timers, etc.) to perform the same task. However, simple processing capacity, the microcontroller will never reach the microprocessor level (in the same condition), because a large part of the integrated circuit microcontroller chip for the realization of other on-chip functions, at the cost of sacrifice part processing ability.
Because the resource on the microchip is very tight, its instructions must be very streamlined, and most of the instructions are shorter than 1 bytes. The design principle of control program is usually that the program can be loaded on the chip ROM, because even adding 1 external ROM will significantly improve the hardware cost of the product. The basic feature of the instruction set of the microcontroller is the simplification of the coding scheme. Microprocessors do not have such features, because their powerful addressing mode makes instruction coding short.