Block diagram and operating principle of a microcomputer

The microprocessor is the basic component of the microcomputer. The ancestor of the microcomputer was the computer. This device was implemented in various techniques, which has been made available by the development of electronic components over time. The introduction of semiconductors and integrated circuits resulted in a rapid development of electronics, and with it computers. The core of a computer is the processor. The implementation of the processor in the integrated circuit is precisely the microprocessor.

Block diagram and operation of the microcomputer

The basic idea behind the operation of a computer was developed by the mathematician von Neumann in the interwar period. The structure proposed by him is called the three-bus structure. Modern microcomputers are also made in this structure. The essential component of a microcomputer is MP microprocessor. It is a sequential logic that requires a CLK clock signal for its operation (Clock). The remaining blocks of the microcomputer are ROM, RAM and input / output circuits (WE/WY).

Block diagram of a microcomputer

ROM memory

ROM memory (Read Only Memory) usually includes the program, according to which the microprocessor operates or at least starts its operation. Therefore, this memory is often referred to as program memory. The program is a record of subsequent instructions executed by the microprocessor. Instructions are binary words and should be part of the microprocessor instruction set. The microprocessor instruction set defines the so-called. order list.


RAM (Random Access Memory) it is designed to hold both input data, interim results, and the end results of microprocessor operation (calculations). In this way, it is used in simple microcomputers used for control and working according to a static program. Such microcomputers are made in the form of an integrated circuit and are called microcontrollers. Universal computers, intended for the implementation of various programs - such as microcomputers PCs (Persona! Computer) they also use RAM to save the program. While microcontrollers are satisfied with a small amount of RAM, then microcomputers should have as much of it as possible.

I / O systems

I / O systems provide communication with the environment. They can be used to input data and programs, as well as to present the results of microcomputer operation or control of external devices. For input / output systems via the so-called. external devices are connected to the interface.

Data bus

Data bus it is used to transmit orders (from the program memory to the microprocessor) and data. In order to obtain the highest possible speed of the microcomputer's operation, this bus is implemented in a parallel form. Each transmitted bit of a node has a line (line). The number of data lines depends on the capabilities of the microprocessor. Bus width (number of data lines) is a multiple of a number 8. This enables the transfer of byte states (I Trouble = 8 bits).

Address bus

Address bus wskazuje blok mikrokomputera, with which the microprocessor intends to cooperate. It is also a parallel bus. The number of address lines depends on the capabilities of the microprocessor. Only the microprocessor issues the addresses. DMA transmission (with direct memory access), when the memory addresses are issued by a special chip, the so-called. DMA driver.