There are a large number of processors in the PICmicro range, each optimized for a particular role. However, they all share the same underlying design, so converting from one processor to another is easy. Some of the PICmicro processors have serial ports, which allow them to communicate directly with other systems.
Some of the PICmicro processors have Analogue to Digital Converters (ADCs) which allow them to measure voltages. Some of the PICmicro processors have Digital to Analogue Converters (DACs) which allow them to produce a particular voltage level under the control of a program. All the PICmicros have a number of Programmable Input Output (PIO) connections which allow them to read digital (on and off) signals.
The PICmicro we are going to use, the PIC 16CF84, provides 13 PIO pins which can be used as inputs or outputs.