A microcontroller is a special chip designed to control various electronic devices. You can read about them on nerdytechy.com blog. Microcontrollers first appeared in the same year as general-purpose microprocessors (1971).
Microcontrollers' developers came up with a witty idea - to combine the processor, memory, ROM, and peripherals inside a single case that looks like a regular chip. Since then, the production of microcontrollers annually is often higher than the production of processors, and the need for them does not decrease.
Dozens of companies produce microcontrollers, and not only modern 32-bit microcontrollers are made, but also 16, and even 8-bit ones (like i8051 and analogs). You will often find almost identical models within each family, differing in CPU speed and memory capacity.
The point is that microcontrollers are used mainly in embedded systems, in toys, machines, in mass home appliances, in-home automation - where you do not need CPU power but rather a balance between price and sufficient functionality.
That's why the oldest types of microcontrollers are still on the go - they can do a lot: from the automatic door opening and lawn irrigation to integration into a smart home system. There are also more powerful microcontrollers, capable of performing hundreds of millions of operations per second and bounded to the teeth with peripherals. They have the appropriate tasks. Thus, the developer first evaluates the task, and then chooses the appropriate "iron" for it.
To date, there are more than 200 modifications of microcontrollers compatible with i8051, produced by two dozen companies, and a large number of other types of microcontrollers. The 8-bit PIC microcontrollers by Microchip Technology and AVR by Atmel, 16-bit MSP430 by TI, and 32-bit microcontrollers by ARM Limited, which is being developed by ARM and sells licenses to other companies for their production, are very popular among developers.
The microcontroller is characterized by many parameters, as it is both a complex software-controlled device and an electronic device (chip). The prefix "micro" in the microcontroller's name means that it is made using microelectronic technology.
During operation, the microcontroller reads commands from memory or input port and executes them. What each command means is determined by the microcontroller command system. The command system is embedded in the microcontroller's architecture, and the execution of the command code is expressed in the internal elements of the microchip of certain micro-operations.
Microcontrollers allow you to control various electronic and electrical devices flexibly. Some microcontrollers models are so powerful that they can directly switch relays (for example, on Christmas tree garlands).
Microcontrollers usually do not work alone but are sealed in a circuit where, in addition to it, the screens, keyboard inputs, various sensors, etc., are connected.
Microcontroller software can attract the attention of those who love to "chase bits," as the memory in microcontrollers is usually from 2 to 128 KB. If less, you have to write on the assembler or Forth, if possible, use unique versions of Basick, Pascal. Still, mostly C. Before finally programming the microcontroller, it is tested in emulators - software or hardware.
There may be a question: the microprocessor and the microcontroller are just different names of the same device, or are they still other things?
A microprocessor is the central device of any computer, made by integrated technology. The name itself indicates that it is where the computational processes take place. To make it a computer, even if it is not very modern and powerful (remember amateur constructions of Radio-86 or Sinclair), it must be supplemented with external devices. First of all, it is RAM and input ports for the information output.
The microcontroller has a processor, RAM, program memory inside itself, and besides a whole set of peripheral devices, which turn the processor into a fully functional computer. In the old Soviet terminology, such devices were called Single Crystal Microcomputers. But Soviet computing equipment, as we know, has reached a dead-end, and with it, the OMEM.
Foreign computing equipment did not stand still, so OMEVM became known as controllers. Controllers proved to be very suitable for controlling various equipment, even not very complicated.