Memories

Abstract

Memories are large arrays of registers arranged so that each register can be accessed (written to or read from) using relatively few control and data lines. The penalty to be paid for having a small number of signal lines is that only a few registers (memory cells) can be accessed simultaneously. The principle advantage of memories is that many memory cells can be placed inside one integrated circuit. For example, a 16kbit memory organized as 2k (2048 to be precise) eight-bit words occupies only slightly more space than one eight-bit register. Each of the 2048 (2¹¹) words has a unique address (position) inside the memory and can be selected by applying this address in the form of an 11-bit binary word to the memory address lines. Data can then be written to or read from the selected word on eight data lines.