16F84 Pin Diagram

Zoltan Padrah edited this page Aug 22, 2012 · 1 revision
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We will go through each pin, explaining what each is used for,

Table of Contents

RA0 To RA4

RA is a bidirectional port. That is, it can be configured as an input or an output.The number following RA is the bit number (0 to 4). So, we have one 5-bit directional port where each bit can be configured as Input or Output.

RB0 To RB7

RB is a second bidirectional port. It behaves in exactly the same way as RA, except there are 8 - bits involved.


These are the power supply pins. VDD is the positive supply, and VSS is the negative supply, or 0V. The maximum supply voltage that you can use is 6V, and the minimum is 2V.


These pins is where we connect an external clock, so that the microcontroller has some kind of timing.


This pin is used to erase the memory locations inside the PIC (i.e. when we want to re-program it). In normal use it is connected to the positive supply rail.


This is an input pin which can be monitored. If the pin goes high, we can cause the program to restart, stop or any other single function we desire. We won’t be using this one much.Ex:Interrupt is used in the case of keypad scanning. When one of the key is pressed the interrupt pin will go high, then the microcontrollers will pause the current program, and it will execute a program to determined the key pressed.


This is another clock input, which operates an internal timer. It operates in isolation to the main clock. Again, we won’t be using this one much either.