This book describes the design and characterisation of interface circuits for the dirct connection of sensors with a time-based output signal to a microcontroller.The topics analysed are (a) the performance of microcontrollers in timing signals, (b) the susceptibility of IC quasi-digital sensors to supply voltage changes and (c) the performanceof direct modulating sensor-to-microcontroller interfaces based on measuring the charging/discharging time of na RC circuit.The authors analyse the features and limitations of these interface circuits, and offer design rules and guidelines for improving their performance.This book interestes designers of microcontrollers and IC sensors, which can apply the theoretical models developed herein to predict and reduce the effects of power supply interference. It also interests electronic circuit designers, which can apply the test circuits, measurement methods and design rules to their own designs. Finally, the book being the result of doctoral thesis, it may inspire other researchers to engage in gaining further insight in some of the topics considered, and help them in learning a systematic approach to hypothesis formulation and testing