Raspberry Pi Assembly Language Programming

Abstract

Digital integrated circuits such as microprocessors recognize signals with two voltage levels representing either a one or a zero, but to be useful they often have to process and generate analog signals with many different levels. Analog interfaces are used for this purpose and they fall into two main categories; a digital-to-analog converter, d-to-a, turns digital information from the processor into an analog output signal with many levels, and an analog-to-digital converter, or a-to-d, senses, analog-input signals and turns them into digital information suitable for the microprocessor. Usually, analog converters are separate integrated circuits but some microprocessors have built-in analog converters. Analog interfaces, the subject of this tutorial, use a number of bits to sense or produce a signal with many possible voltage levels.