This application note describes a method for implementing analog to digital (A/D) conversion on the PIC16C5X series of microcontrollers. The converter requires only five external components and is software and hardware configurable for conversion resolutions from 6-bits up to 10-bits and conversion times of 250ms or longer. The method is usable for both voltage and current conversion and uses a software calibration technique that compensates for time and temperature drift as well as component errors. PIC16C5X microcontrollers are ideal for simple analog applications because: