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)
40 pins PIC Microcontrollers 16f877a
2)
Breadboard for testing / Cupper Plate for PCB
3)
Voltage regulator LM7805
4)
4 MHz Crystal Oscillator
5)
40 pins Connector for the PIC Microcontrollers
6)
Jumpers
7)
Batteries generating DC voltage
8)
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(1000);
output_low(PIN_B7);
delay_ms(1000);
}
}
is used to mechanically support and electrically connect
electronic components using conductive pathways, tracks or
signal traces etched from copper sheets laminated onto a nonconductive 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)
2)
3)
4)
Make the schematic and design on EAGLE CADSOFT
Print Design on two transparent papers with actual size of design
Stick the two papers perfectly together
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 to design PCB and it should be done in
reality .. But for simplicity 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