2. PIC Microcontroller
2.1 An overview
The PIC (Programmable Interface Controller) line of microcontrollers was originally developed by the semiconductor division of General Instruments Inc. The first PICs were a major improvement over existing microcontroller because they were programmable, high output current, input/output controllers built around a RISC (Reduced Instruction Set Code) architecture. The first PICs ran efficiently at one instruction per internal clock cycle, and the clock cycle was derived from the oscillator divided by 4. Early PICs could run with a high oscillator frequency of 20 MHz. This made them relatively fast for an 8-bit microcontroller, but their main feature was 20 mA of source and sink current capability on each I/O (Input/Output) pin. Typical micros of the time were advertising high I/O currents of only 1 milliampere (mA) source and 1.6 mA sink [5]. 2.2 PIC16F887 Microcontroller