parallel expansion of the bus can be avoided

Single chip microcomputer is an important branch field of computer development. According to the current development situation, single chip microcomputer can be roughly divided into general-purpose / special-purpose type, bus type / non bus type and industrial control type / home appliance type from different angles. 1. General purpose type / special purpose type are distinguished according to the scope of application of single chip microcomputer. For example, 80C51 is a general-purpose MCU, which is not designed for a special way; Special single chip microcomputer is designed and produced for a class of products or even a certain product. For example, in order to meet the requirements of electronic thermometer, it integrates the temperature measurement and control circuit with ADC interface and other functions in the chip. 2. Bus type / non bus type is distinguished by whether the single chip microcomputer provides parallel bus. Bus type single-chip computers are generally equipped with parallel address bus, data bus and control bus. These pins are used to expand parallel peripheral devices, which can be connected with single-chip computers through serial ports. In addition, many single-chip computers have integrated the required peripheral devices and peripheral interfaces into one piece. Therefore, in many cases, parallel expansion of the bus can be avoided, greatly reducing the packaging cost and chip volume, This kind of single chip microcomputer is called non bus single chip microcomputer. 3. Control type / home appliance type are distinguished according to the roughly applied fields of single chip microcomputer. Generally speaking, the industrial control type has a large addressing range and strong computing ability; Single chip computers used in household appliances are mostly special-purpose, usually small package, low price, and high integration of peripheral devices and peripheral interfaces. Obviously, the above classification is not unique and strict. For example, 80C51 single chip microcomputer is both general-purpose and bus type, and it can also be used for industrial control.