The PIC16F84 device by Microchip is a very basic but useful device. It's the most popular of all the MC devices. The device conatains 2 ports: PORT A and PORT B. PORT A contains 5 Bits and PORT B contains 8 Bits.
|PORT A||0, 1, 2, 3, 4|
|PORT B||0, 1, 2, 3, 4, 5, 6, 7|
The typical "basic" wiring diagram consists of +5 VDC to Vcc and MCLR. Ground is taken to the Vss pin. The OSC 1 and OSC 2 pins are used to connect to the occilation part of the circuit. This can be as simple as a crystal, resonator or even a resistor/capacitor (RC) network. I like to use resonators with built-in caps. This allows for a simple wiring set-up. The outer 2 pins of the resonator go to the OSC1 and OSC 2 pins. The center pin of the resonator goes to ground. When the device has power and is running a program, you can easily reset the device by shorting MCLR to Vss (ground).