Circuit Design: Know It All

Chapter 34

Microcontroller Toolbox

Stuart Ball

This chapter contains some miscellaneous topics that pull together multiple concepts from preceding chapters.

34.1 Microcontroller Supply and Reference

In many cases, you can minimize the effects that supply voltage can have by referencing your analog inputs to the supply voltage. Figure 34.1A shows a thermistor connected to an analog input and using a pull-up to a precision reference voltage. At first glance, it might appear that this is a very accurate design because the precision reference gives a repeatable voltage versus temperature at the analog input. The problem with this design is that the microcontroller is measuring the temperature using the supply voltage as a reference, so the overall accuracy ...