TABLE OF CONTENTS By J.W. Bruce
This chapter discusses a few of the many different analog-to-digital converter (ADC), digital-to-analog converter (DAC) architectures, and the advantages and disadvantages of each. The PIC18's successive approximation ADC and a serial DAC are covered and example applications are explained.
After reading this chapter, you will be able to:
Select the appropriate ADC and DAC architecture based on the application requirements.
Implement a simple data acquisition system using the PIC18's analog to digital converter.
Construct a parallel R-2R resistor ladder flash DAC using the PIC18.
Implement a PIC18 to I 2C serial DAC interface.
Construct a simple three-function waveform generator with the PIC18.
As predicted by Moore's Law in 1964 [1], digital computing power has exponentially increased at ever smaller, incremental costs. For example, as we've seen in the previous chapters, the PIC18 has the capability of replacing several chips. With this increase of computing power, many applications usually accomplished with analog circuitry have found a new lease on life in the digital realm. However, the real world still is and will always continue to be a fundamentally analog place. To bring the digital processing of the PIC18 and its benefits to bear on real-world applications, the analog signal of interest must be translated into a format the PIC18 can understand. This is the function of the analog-to-digital converter (ADC). After processing by the PIC18, the resulting digital stream of information must be returned to its analog form by a...
