1 - Microcomputer bus systems

Abstract

Microcomputer memories consist of a large number of individual storage locations. Each storage location contains a memory cell that is capable of storing a single binary digit. The construction of a typical memory cell is similar to that used for the bistable or flip-flop circuit. When a microprocessor transfers data to and from memory, it is important that only one storage location is selected at any given time. Each location is assigned a unique identifying label called an address. Selection of one particular location within memory is achieved by applying the correct address to the memory address input lines. Microcomputer memories make use of binary addresses because this reduces the number of address lines necessary for a given size of memory. To enable selection of a single location to take place, the binary address that is applied to a memory must first be decoded. To minimize the amount of interconnecting wiring in a microcomputer, a bus structure is used in which groups of parallel conductors, called busses, are used to convey the information from one part of the system to another.