There are several types of single chip microcomputers

Microcontrollers (microcontrollers) is a kind of integrated circuit chip, which is a small and perfect microcomputer system composed of a small and perfect microcomputer system composed of a silicon wafer that uses ultra-large-scale integrated circuit technology to integrate the best processor CPU, random access RAM, read-only memory ROM, a variety of IO ports and interrupt systems, timer counters and other functions (which may also include display drive circuits, pulse width modulation circuits, analog multiplexers, AD converters and other circuits) into a silicon wafer.

According to the development of single-chip microcomputer, from different angles, single-chip microcomputer can be roughly divided into general-purpose special type, bus type, non-bus type and industrial control type household appliance type.

1. General-purpose and special-purpose type. This is distinguished by the scope of application of microcontrollers. For example, the 80C51 general-purpose microcontroller is not designed for a specific purpose; The special microcontroller is designed and produced for a class of products or even a certain product, for example, in order to meet the requirements of electronic thermometers, the temperature measurement control circuit with ADC interface and other functions is integrated in the chip.

2. Bus type Non-bus type. This is differentiated by whether microcontrollers provide parallel buses. The bus-type single-chip microcomputer is generally provided with a parallel address bus, a data bus, a control bus, these pins are used to expand the parallel peripheral devices can be connected with the single-chip microcomputer through the serial port, in addition, many single-chip microcomputers have integrated the required peripheral devices and peripheral interfaces, so in many cases can not expand the bus in parallel, greatly reduce the packaging cost and chip volume, this kind of single-chip microcomputer is called non-bus single-chip microcomputer.

3. Industrial control type household appliance type. This is based on the general application field of microcontrollers. Generally speaking, the industrial control type has a large addressing range and strong computing power; Most of the single-chip microcomputers used for home appliances are special-purpose, usually small packages, low **, and high integration of peripheral devices and peripheral interfaces.

Obviously, the above classification is not unique and strict. For example, the 80C51 single-chip microcomputer is both general-purpose and bus, and can also be used for industrial control.

According to the bus, there are: 8-bit machine, 16-bit machine, 32-bit machine, 64-bit machine.

The development of single-chip microcomputer has gone through 4-bit, 8-bit, 16-bit and 32-bit stages. 8-bit single-chip microcomputer is widely used in industrial control, intelligent interface, instrumentation and other fields due to its strong function, 8-bit single-chip microcomputer still occupies the mainstream position in medium and small-scale applications, representing the development direction of single-chip microcomputer, and plays an increasingly important role in the field of single-chip microcomputer application.

In the early 80s, Intel introduced the 8-bit MCS-51 series of microcontrollers. The logic components of the MCS-51 microcontroller include an 8-bit CPU with on-chip oscillator, 80514B mask ROM, 87514kbePROM, and 8031 ROM-less.

Special function register SFR128BRAM, timer counter T0 and T1, parallel IO interface: P0, P1, P2, P3; Serial interface: txd, rxd; Interrupt system: int0, int1.