PCB Design Introduction - GUC - Faculty of Information Engineering

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Transcript PCB Design Introduction - GUC - Faculty of Information Engineering

PIC Microcontrollers are very advanced devices used in many embedded systems applications in our daily life applications

1) 2) 3) 4) 5) 6) 40 pins PIC Microcontrollers 16f877a Breadboard for testing / Cupper Plate for PCB Voltage regulator LM7805 4 MHz Crystal Oscillator 40 pins Connector for the PIC Microcontrollers Jumpers 7) 8) Batteries generating DC voltage Capacitors 22u Farrad 9) Resistors 10k ohm 10) LEDs with different colors for testing

Write a C program to flash / blink LEDs

#include < 16f877A.h

> ; #use delay (clock = 1000000 ) #fuses XT , noput void main(void) { while (1) { output_high(PIN_B7); delay_ms( delay_ms( 1000 1000 ); output_low(PIN_B7); ); } }

is used to

mechanically support


electrically connect

electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non conductive substrate. It is also referred to as printed wiring board (PWB) or etched wiring board.

Design is much better and having many advantages 1) Clear design 2) Make design away from short circuits 3) Make inexpensive design 4) Make Highly reliable design 5) Faster design for high volume production

is considered better than the design on bread board and more reliable without jumping wires and extensions that could be a reason for the short circuit (SC), so the bread board could be a way to test the hardware but could not be considered as final implementation

has many steps required for its design 1) Make the schematic and design on EAGLE CADSOFT 2) Print Design on two transparent papers with actual size of design 3) Stick the two papers perfectly together 4) Put it in the UV light machine and vacuum the air everywhere

5) Take it directly to the developer solution and drop it many times inside it till all photoresist will be removed and the patterns of wires appear( from 1 - 2 mins) 6) Then put it inside the etching solution to get rid of all not needed copper and only remains the needed copper for wiring ( from 15 – 20 mins) and at 50 degrees

7) Check under microscope if it contains short circuits (SC) or with Multimeter and if there is any short circuits etch it again till all is gone 8) Then put is again in UV light machine to get rid of all photoresist 9) Make holes required for the design by the drilling machine size 10) Start soldering ICs in its suitable places according to your design

These steps are required reality .. But for simplicity to design PCB and it should be done in hand out your design and you will get it printed and ready for soldering and integrating ICs on it.

Soldering process will be discussed later in details

http://www.cadsoftusa.com/downloads/?language=en Version 5.11 DEMO is available on the download links http://www.pcb-pool.com/ppuk/service_specifications.html

http://www.piclist.com/images/www/hobby_elec/e_eagle20.htm#2 http://www.hcilab.org/resources/boardlayout/eagle-librarydesign.htm

Main menus toolbar Schematic area Toolbox

Main menus toolbar Layout Area Toolbox

It is the package that allows the usage of devices with Pins and holes on the PCB It is the package that allows the usage of Surface Mount Devices on the PCB

1) If it is available for you to use connectors go on 2) Always check DRC while working to know exactly where is your error 3) Always use the name and the value of any element to make your design clear and prepared well for soldering 4) Try to compress the area of your design as possible 5) Make always capacitors between higher and lower Voltage supplies 6) Make the Power signal and ground more thick in the design to be distinguished from wires of signals

7) Use capacitors beside the connectors 8) Make shorter paths and try to lower the number of crossing wires and try first to do your best for fitting your design on one-sided PCB, After than think about the other possibilities because it is more expensive 9) After finishing your design create a ground plane which means anything else except for the signals, power lines will be considered ground 10) Area you will work on will be given in the project document and instructions

1) Adjust working directories for Files, projects and libraries 2) Adding libraries to eagle library 3) Add elements to eagle library from its data sheet with real physical dimensions 4) Printing your design 5) Change elements through layers like texts