Without operating system, some low-level COS supporting multi-task appeared in the early days. But in essence, the application of COS still needs to deal with the underlying hardware. When more complex and expensive single-chip computers appear, it is possible to make application development completely independent of the bottom layer and its version, which is with the help of the operating system. A few professional bottom-level developers support a large number of application developers, which greatly reduces the technical and knowledge requirements. Developing applications only requires understanding the underlying application development interface. It has greatly accelerated the progress of application development and expanded the population who can develop applications.
Single-chip microcomputer is an integrated circuit chip, which is a small and perfect microcomputer system formed by integrating the functions of central processing unit (CPU), random access memory (RAM), read-only memory (ROM), various I/O ports, interrupt system, timer/counter, etc. (possibly including display drive circuit, pulse width modulation circuit, analog multiplexer, A/D converter, etc.) on a silicon chip by using VLSI technology. From the 1980s, from the then 4-bit and 8-bit single-chip microcomputer to the present 300M-meter high-speed single-chip microcomputer.
Single-chip microcomputer, also known as single-chip microcontroller, is not a chip to complete a certain logical function, but to integrate a computer system into a chip. It is equivalent to a microcomputer. Compared with computers, single-chip computers just lack I/O equipment. 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.
Single-chip microcomputer has been widely used, such as intelligent instruments, real-time industrial control, communication equipment, navigation systems, household appliances and so on. Once the single-chip microcomputer is used in various products, the products can be upgraded.