PIC 16F84 - Beginner's Guide

The microcontroller PIC16F84 can be considered a very little but complete computer, build on an unique 18 pin integrated circuit.

Featured with program memory, user ram, internal peripherals and I/O ports, this microcontroller can send and receive signals and perform some logical operations.

Requires a power supply from 3 to 5.5V, and a supply current of only 2mA.

Externally, this microcontroller appears like a common IC TTL or CMOS, but internally we can find all the components of a microprocessor system:

• a CPU, Central Processor Unit, for executing program instruction
• a PROM memory (Programmable Read Only Memory) for the program storage in permanent mode (not volatile)
• a RAM memory, useful to work with program variables (volatile)
• a series of I/O ports, to drive actuators or leds
• a number of useful devices like timers, clock generators etc.

The PIC16F84 is an intermediate device of the large PIC family (You can find all PIC products at the Microchip website).

The 16F84 has a FLASH EEPROM memory for the program storage, Electrically Erasable Programmable Read Only Memory, who lets the designer to write programs in this device up to 10,000 times, and make possible the on-board programming.

It offers 13 pins on 18 totals for I/O, distributed on one principal "RB" with 8 ports, and the second "RA" with five I/O lines.

14 Vdd = power supply
5 Vss = power supply
4, 16, 17 = PIC oscillator and Reset
all the others are for I/O