protel dxp tutorial

Protel DXP PCB Layout

Glenn Mercier12/16/2005

PCB Layout Software

There are many PCB Layout software packages available. For this tutorial, I will be using Protel DXP.Protel DXP 2004Orcad LayoutEagle Layout EditorExpress PCBPADS

Introducing Protel DXP 2004

Reasons for Choosing Protel DXPAbundance of learning luides

http://www.altium.com/Community/Support/LearningGuides/

Large footprint library includedExtensive design rule checking (DRC)Integrity testingIntegrated software packageFree Trial Available

Main Screen

Create new PCB Project

The project was created (*.PrjPCB), but needs to be saved, right click and save the project

Save the PCB Project File

Create New Schematic

Now we need to add files to the project. The beginning step is to add a Schematic Document. This is where the schematic drawings we are all familiar with will go. Right click and save the schematic document as before.

Organization

Your screen should now look like this. Notice the branching. The PIC schematic document is located in the project tutorial.

Libraries

There are three forms of librariesSchematic Library- This library contains schematic drawings that we are familiar with from ORCADPCB/Footprint Library- This library contains the actual dimensions and pads for placing the component on the board.Integrated Library- Most manufacturers libraries are integrated, containing both Schematic and PCB libraries.

Adding Libraries

From the design menu, click Add/Remove libraries.

Adding Libraries (Cont.)


Since most of us are using Microchip PIC microcontrollers, add the Microchip library


Each manufacturer usually categorizes their parts for easy selection. Choose the PIC18

Adding Libraries (Cont.)Add the highlighted libraries to the project. These two files are not in a folder, but in the root ‘Library’ folder


From the Library folder, go to the PCB folder, this folder contains PCB footprint libraries.


From the PCB folder, add Chip CapacitorChip ResistorCrystal OscillatorResistor- Axial


You should now have the following libraries installed. Note the top three libraries here are integrated libraries, and the bottom four libraries are PCB libraries

Checkpoint

If you expand the libraries folder, you should see the following. Now that we have added our libraries, we are ready to begin the schematic layout.

Schematic Layout

Double Click on your schematic document from the left navigator menu, and you should see a blank screen on the right

Schematic Layout- Placing Parts

From the ‘Place’menu, click Part.


The ‘Place Part’screen will appear. Click the box in the top right with the […]. This will bring up the ‘Browse Libraries’, which is just a list of a few default libraries and all the libraries we have added to the project.


From the ‘Libraries’drop down box, look for the Microchip Microcontroller library we added earlier.


Choosing the PIC18F452 for our project we see there are three choices in the list. Which one do we choose? Why is there three options for one part?This is where the footprint comes in. Although the PIC18F452 has the same electrical and logic properties, the physical packaging comes in three different forms.

PLCC- 44 PinsQFN- 44 PinsDIP- 40 Pins


Don’t worry if you don’t know what terms like PLCC, QFN, TQFP, DIP mean at the moment. You can look at the Protel layout and it will show you what the footprint differences are.


PIC18F452-E/L : This is a PLCC-44 package. In the bottom left corner you can see the description of the package including dimensions.

Schematic Layout- Placing PartsPIC18F452-E/ML : QFN package. Notice when you highlight a part, Protel shows both the schematic layout (top right) and the PCB layout (bottom right).

Schematic Layout- Placing PartsPIC18F452-E/P : 40 pin DIP package, DIP’sare very good for beginners due to their large size and easy solderability


Which to choose? That’s up to you! But for this tutorial, lets use a DIP package


Once you click ‘ok’ on the part, you’ll be brought back to the ‘place part’ popup menu. This allows you to verify the part you chose

Schematic Layout- Placing PartsYour PIC should now be placed in the schematic document. A very important note is that you need to give this an identifier. If you leave this as ‘U?’ you will get an error. So double click and change the identifier to U1

Schematic Layout- Placing PartsDouble click on the PIC, you will get a Component Properties popup box. Here you can leave notes on the part, change the footprint,change the description, and add a rule for this part. If you click on ‘Edit’in the bottom right, it will show you the PCB footprint for this part

Schematic Layout- Placing PartsWe need power for our circuit, but unlike pspice, we must add a physical way to add power to our device. Add ‘HEADER 2’ from the Miscellaneous Connectors library. As seen from the PCB footprintbelow, this is just two holes in the board where we can connect wires.


Our updated schematic looks as follows. Click the place wire icon from the menu bar up top.

Schematic Layout- Placing PartsBe EXTREMELY CAREFUL when connecting wires. The end of the wire must be on the end of the part, when this happens you will get a red ‘X’, Do not rush through this step, and always verify there is a proper connect.

WRONG!!!!!!

Gray ‘X’ This will not connect the part

Correct

Red ‘X’ This WILL connect the part

Schematic Layout- Adding NetsOn simple projects, it makes sense to run wires making connections, but on larger projects this often makes things verycluttered, difficult to make changes, and often results in errors due to wires crossing. Draw a small wire extending from VSS (GND), and a small wire from the other pin on the pin header (as shown in next slide). Click the ‘NET’ icon in the toolbar and place this text on both lines, labeling them both GND. This is the same exact thing as actually running wires between them. Protel knows that these two pins should be connected.

Schematic Layout- Adding NetsYou should now have the following. Notice the blue dots on pin 12 and pin 11, the dots appear when more there is a connect of more than 2 areas. In the case of the blue dot on the left, this connects pin 12, pin 31, and GND all together.

Schematic Layout- Adding Nets

The usefulness of nets cannot be over emphasized here, it may seem like extra work, but DO IT!!

Allows for cell design of layout, This makes design neat, orderly, easy to troubleshoot.Looks professionalMajor changes such as changing an 8 connection port from port A to B is simple to just move the NETS, rather than rewire 8 different wires.Can create multiple schematic documents (advised), and link nets across schematics

Schematic Layout: No Nets- Hardwired Schematic

Schematic Layout- Using Nets

50RT1

+3.3V PROG

3.3V

330RT3

+5V

VCC

NCNC

IRQDOUT

GNDCLK

+3.3VGNDDIN

CS

J3

SD Breakout

SDCSMOSI

3.3VSDCLK

MOSOSDIRQ

50RT4

LED Test

LEDTEST

S3SW-PB

LOGLOC

VCC

3.3V

1.8V

S4SW-PB

10kRT9

CDISP

12

J5V5V Current Monitor

12

J333.3V Current Monitor

12J181.8V Current Monitor

LED Indicators

Current Monitors/External Power

Button Presses

Jumpers

10kRT10

Reset

1nF

CT3Cap

S2HW-RESET

VCCX

+1.8V

50RT2

1.8V

470RT5

100RT6

Log Loc

3.3V12

JPICPIC

3.3V

VSOURCE = 3.3VVCCX = PIC VCC

NORMAL OPERATION: VCC = VCCX (jumper closed)

PROGRAMMING MODE: VCCX is isolated, therefore the PIC is isolated from the rest of the circuit

VCCX

MCLR

3.3V

12

JBATTBATT Current Monitor

VBATT VS

1nF

CT1Cap

1nF

CT2Cap

11AGND

Aux Power

11A50

Aux Power

11A33

Aux Power

11A18

Aux Power

Schematic Layout- Using Nets

0.1uF

CU1Cap 0.1uF

CU2

ICSP Data

MCLR

DB4DB5DB6DB7

LCDE

VCCX

ICSP CLK

CLKO

CLKI

XTALXT 1 MHz = 15 pfXT/ HS 4 MHz = 15 pfHS 8 MHz = 15-33 pfHS 20MHz= 15-33 pfHS 25MHz= 15-33 pf Higher C increasesstability but increasesstart up time

R11 used in HS modeto avoid overdriving thecrystal.

20pF

CU3

Cap

20pF

CU4

Cap

CLKO

CLKI

10kRU2

VPP/MCLR 1

+5V 2

GND 3

DATA 4

CLK 5

ICSP

ICSP Port

MCLR

0.1uFCU5

Cap

VCCX

ICSP CLK

ICSP Data

LEDTEST

LCDRSGND

VDD 71

RD0/AD0/PSP072

RE7/AD15/CCP2/P2A 73RE6/AD14/P1B 74RE5/AD13/P1C 75RE4/AD12/P3B 76RE3/AD11/P3C 77RE2/AD10/CS/P2B 78

RH0/A16 79

RH1/A17 80

RH2/A18 1

RH3/A19 2

RE1/AD9/WR/P2C 3RE0/AD8/RD/P2D 4

RG0/CCP3/P3A 5

RG1/TX2/CK2 6

RG2/RX2/DT2 7

RG3/CCP4/P3D 8

RG5/MCLR/VPP 9RG4/CCP5/P1D 10

VSS11 VDD 12

RF7/SS 13RF6/AN11 14RF5/AN10/CVREF 15RF4/AN9 16RF3/AN8 17RF2/AN7/C1OUT 18

RH7/AN15/P1B 19

RH6/AN14/P1C 20

RH5/AN13/P3B 21

RH4/AN12/P3C 22

RF1/AN6/C2OUT 23RF0/AN5 24

AVDD 25AVSS26

RA3/AN3/VREF+27 RA2/AN2/VREF-28 RA1/AN129 RA0/AN030

VSS31 VDD 32

RA5/AN4/LVDIN33 RA4/T0CKI34

RC1/T1OSI/CCP2/P2A35 RC0/T1OSO/T13CKI36

RC6/TX1/CK137

RC7/RX1/DT138

RJ4/BA0 39

RJ5/CE 40

RJ6/LB 41

RJ7/UB 42

RC2/CCP1/P1A43

RC3/SCK/SCL44

RC4/SDI/SDA45

RC5/SDO46

RB7/KBI3/PGD47

VDD 48

OSC1/CLKI49

OSC2/CLKO/RA650

VSS51

RB6/KBI2/PGC52 RB5/KBI1/PGM53 RB4/KBI054 RB3/INT3/CCP2/P2A55 RB2/INT256 RB1/INT157 RB0/INT058

RJ3/WRH 59

RJ2/WRL 60

RJ1/OE 61

RJ0/ALE 62

RD7/AD7/PSP763 RD6/AD6/PSP664 RD5/AD5/PSP565 RD4/AD4/PSP466 RD3/AD3/PSP367 RD2/AD2/PSP268 RD1/AD1/PSP169

VSS70

UPIC18LF8722

PIC18LF8722-I/PT

GPSTXAGPSRXA

10kRU1

ALFATRS

ALFATCTSALFATRTS

ALFATTXALFATRX

12

XTAL114.7456 MHz

GPSRXBGPSTXBGPSTMGPSRS

GPIOAGPIOBGPIOCGPIODGPIOEGPIOFGPIOGGPIOH

LOGLOC

18VON

DS1820

CDISP

33VON

5VON5VOFF

For Normal Operation5VON - high5VOFF - low18VON- high33VON- high

GPS General I/O Pins

GPS Functional Pins

User ModificationPins

LCD Data

ALFATPort

ALFAT-STDALFAT-STD***HIGH- STD MODELOW- EXTENDED MODE

1-Wire Temp Sensor

0.1uF

CU8Cap

Set as Outputs

100

RU4

100pF

CU7Cap

100pF

CU6Cap

PGD - limits slope of edges, attenuates high freq components100*100pf = 10uS time constant (much less than programmer frequency)

PGC- 100pF reduces Z at high frequencies, which reduces crosstalk

100

RU3

BUSBSELBENBBSTAT1BSTAT2

Creating Custom Parts

Sometimes a part will be required and no library associated with it. For this, we need to make both a schematic and a PCB footprint for the part.

Lets assume we wish to build a part where we will take test measurements from such as voltage levels.


From the file menu, create a new schematic library, and a new PCB library. Save these libraries under a name you will remember.


Select/Highlight the schematic library you just created and click ‘SCH Library’ in the bottom corner of the project menu


This shows information about the schematic library and a list of the parts inside the library. Click the ADD button to add a new part.


Click on the place rectangle for our part. Keep in mind this is what we will see on our schematic

Creating Custom PartsNow click the ‘Place Pin’. If we choose to have test points that include VDDGNDMCLRB.0

We will need 4 pins, add these now


Double clicking on the pins allows you to change the pin number (important) and label the purpose of the pin

Creating Custom PartsClick on the part in the schematic listing on the left. It is up to you to leave comments, description, and designators for the part. Notice the pin listing in the bottom left. In this example:Pin1 = VDDPin2 = GNDPin3 = !MCLRPin4 = B.0

It is very important to remember this order for when we create the footprint


Our schematic part is now complete, click the Project in the bottom left corner to get back to the main project listing. This bottom toolbar will be used a lot.


Notice that there is a red page next to the schematic library (Schlib1.SchLib) we just created. This means there have been changes to the document and it needs to be saved.


Now we need to create the PCB footprint for our part. As we did for the schematic library, highlight the PCB library we created and then click the PCB library tab at the bottom. This expands the library and shows all the components inside the library

Creating Custom PartsProtel can either work in mm units, or in mils.1” = 1000 mils = 25.4mm1mm = 39.4 milsMost datasheets are given in millimeters, but for practice, we will use mils. Pressing ‘Q’ will toggle the units between mm and milsMake sure mils are the unit in the bottom left corner.

Creating Custom PartsThe first thing we will do is orient the footprint at the origin. For this;Draw a line (shown

below)Change the start coordinates to X=0, Y=0End coordinates X=400, Y=0Check to make sure units are listed as mils, if not, go to the previous slide


The line you created will probably disappear, it has simply moved off the visible grid. If this happens, click the ‘fit document’option. This will automatically zoom in on the line we created.

Creating Custom PartsDouble click on the line, and change the layer to ‘Top Overlay’. We are simply using this line as a box that will hold our pinsTop Layer= Copper Trace (Red)Top Overlay= Legend (Yellow)It is very important to use the right layer

Creating Custom PartsSingle click on the line to select it, click Ctrl-C to copy the line and then place the line anywhere.Again, open up the dimensions and make the starting point X=0, Y=200

and the ending pointX=400, Y=200You should have the following on the right at this point


Continue the same procedure as before, but use the following points for two linesStart: X=0, Y=200: End: X=0, Y=0Start: X=400, Y=200: End: X=400, Y=0

This will complete the box. You can also just draw a line and change the layer to top overlay, but it is good habit to be as precise as possible when dealing with PCB footprints.


Click the ‘Place Pad’ icon as shown below and place a single pad.

Creating Custom PartsDouble click the pad, and notice the hole dimensions. Make the hole size 35 mils. Many PCB Manufacturers have a limitation on the ‘Annular Ring’ size, the annual ring is the diameter of the pad – diameter of the hole divided by 2. EX: If the annular ring minimum is 7.5 mils, and the hole size is 35 mils, the pad size must be a minimum of 50 x 50 mils

Creating Custom PartsNotice the designator = 0, this number will correspond with the pin numbers we chose in the schematic part we made for this. Also there is an option for multi-layer, this means there is a hole through the board. For surface mount parts, this will need to be changed to TOP LAYER (again it will be color coded red).


Change the designators as shown below, this corresponds to the pin numbers we chose earlier. Notice how the holes are not aligned in any manner.


Hold down shift and single click each hole, they should all be selected now. Right click on any of the holes, and click ‘align’for custom alignment options.

Creating Custom PartsAnother way is to pull up the first pad, notice the X and Y coordinates.Pad 1: X=50, Y=130Pad 2: X=150, Y=130Pad 3: X=250, Y=130Pad 4: X=350, Y=130

This method is preferred because it makes it easier to align strange components (such as the footprint for an SD Flash Card)


Now we need to label the pads, click the ‘Place String’ icon


Make the following changes to the text:

Layer = Top OverlayHeight = 40 milWidth = 7 milRotation (change if desired)

NOTE: Mirrored text is for placing text on the back of the PCB


Our spacing and text choices do not allow us to place the text horizontal, so we must resize the box and rotate the text.


Now we must link the schematic part with the PCB part we just made. Click the ‘project’ tab in the bottom left corner and open the schematic library again. Double click the component you made to bring up the component properties page.


From the component properties page, click the ‘add’ in the bottom right corner. We are adding the footprint to this schematic, so select footprint and click ok.


From the PCB Model popup box, click ‘browse’


Select your custom footprint/pcb library from the list

Creating Custom PartsSelect the footprint desired from the library. Since this is the first footprint we have created there is only one in the list. Click ok when done


This should bring you back to the model page, where you can verify the footprint choice you made


In the schematic editor, we can now verify that there is a PCB footprint associated with this schematic, and verify that the pins on the schematic match the pins on the footprint we created.

Schematic Editing

Click the ‘project’ tab in the bottom left corner and go back to the schematic layout. Add the new part to the schematic. Note that the footprint is present and the pins match the schematic drawing.

Schematic Editing

Make the following changes to the schematic

PCB Layout Editor

Our schematic drawing is now complete, now we want to transfer this to a PCB. Be sure to be careful to associate all parts with the proper footprints, and verified each footprint before even beginning to think about PCB layout.

PCB Layout Editor

Click the ‘files’tab in the bottom left corner, and minimize some of the arrows until you can see the PCB Board Wizard. Click on the wizard.

PCB Layout Editor

After an introduction to the wizard screen, and choosing your default units, you will get to the following screen. Choose ‘custom’ for now.

PCB Layout EditorChoose the dimensions of the board, remembering that 1000 mils = 1”. Choose rectangular shape, as other shapes are very costly. Leave the other options as default.

PCB Layout Editor

Choose signal layers = 2, Power planes = 0 Most projects can be done with these settings.

PCB Layout Editor

Vias are holes that electrically connect different physical layers together. Select Thruhole Viasonly. Blind and Buried vias are for multi layer boards and usually very expensive.

PCB Layout Editor

Choose the following options. Number of tracks between adjacent pads is simply a rule for the auto router. To keep costs low, make sure to put components on only one side of the board.

PCB Layout Editor

Board Manufacturers will always clearly state the minimum track size, via size, and clearance. Most board houses can easily fabricate the settings to the right. Note the annular ring size of 7.5 mils

PCB Layout EditorYou should now see the following: the new PCB is listed under “Free documents”, click and drag this into your project file, and save with an appropriate name.

PCB Layout Editor

Right click in the PCB Layout editor, and go to board options as shown below.

PCB Layout Editor

Change the following options:

Uncheck Display sheetVisible Grid Markers = Dots

PCB Layout EditorYour PCB document should now be under your project directory. Notice the pink trace around the outside of the board, this is the keep away layer. Only items inside this pink box will be fabricated.

PCB Layout EditorFrom the schematic editor, go to ‘Design’ and then click ‘update PCB Document in xxx.PcbDoc’. This will import your schematic into the PCB Editor

PCB Layout EditorThe Engineering Change Order box will open. This shows a list of added components and nets that are being imported into the PCB Document. Click Validate.

PCB Layout EditorAfter validating, if no errors are found, click execute, you will see green arrows if everything was successfully imported into the PCB document. If you forgot to include a footprint, or if different components have the same identifier, you will get an error.

PCB Layout Editor

After executing, close the box and you will see all your footprints neatly aligned outside of your PCB board.

PCB Layout EditorYou can click and drag your components onto the board, delete the ‘sheet’ it was resting on, and your layout should look similar to this. The thin gray lines are called a ‘rats nest’. It shows which holes are to be connected to each other but there is no actual connect there yet. The PCB editor knows this from your schematic drawing.

PCB Layout Editor

Notice the tabs in the bottom, right now the top layer is selected. This means that the top layer is the active layer, and any changes will occur on the top layer.

PCB Layout Editor

It is common practice to run traces on each layer of the board orthogonally. If you choose to route the top layer horizontally, then route the bottom layer vertically. This may seem like more work than it’s worth, but on complicated circuits it makes routing a lot easier. This method also limits distributed capacitance across layers.Avoid angles that are 90 degrees or lessKeeps traces are large as possible for physical robustness, and decreased parasitic resistance.

PCB Layout Editor

Click the icon to interactively route components as shown in the diagram. Once you click on a net in the circuit, it will highlight that net to show where the connects need to go. The VDD connection was made here, and there are four pins that need this connection.

PCB Layout Editor

Run the VDD trace from P2 horizontally and then place a VIA on the end of the line.

PCB Layout Editor

Click the ‘bottom layer’ tab in the bottom, and then draw a trace vertically towards the connect pin. This trace will be in blue to indicate it is located on the bottom of the board.

PCB Layout Editor

One connection has now been made. Since P1 are both through hole connections, we can let this trace connect on the bottom of the board.

PCB Layout Editor

Route the rest of the traces. Note that the top layer traces are horizontal and the bottom layer traces are vertical.

PCB Layout Editor

Click the Rules option under the Design menu.

PCB Layout EditorHere you can spend time changing rules to manufacturers specifications. If you are unsure what a rule means, usually there is a diagram which gives an idea of the meaning.

PCB Layout Editor

Now the physical layout is complete, and it is time to run a design rule check on the layout. This checks all the rules you made. Start the DRC

PCB Layout Editor

Uncheck the ‘Create Report File’, and leave the rest of the options default.

PCB Layout Editor

When the DRC is done, a message box will pop open and report any violations. When it is blank, like in the picture, there are no DRC errors.

PCB Layout EditorGround and Power are critical to the circuit. For too many reasons to mention here, you can add polygon pours, which are slabs of copper, to create a large ground area. This helps ensure that the ground layer has the same potential across the circuit. Click on the polygon pour icon at the top of the screen.

PCB Layout EditorMake the following changes to the polygon pour. We want to connect this pour to the GND node, on the top layer of the board, and also remove dead copper. Select ‘OK’ and then click the four corner points you want for the pour.

PCB Layout EditorThe polygon should look similar to the picture on the right. Notice in the bottom picture, you can see that the polygon is connected to the GND node, but never contacts the VDD node.

PCB Layout Editor

Perform the same procedure on the bottom of the board, but this time connect it to VDD.

PCB Layout EditorPolygon Pours should be added at the end of design. On large projects, these can be very memory intensive to display. Shelving polygon pours keeps them present, but just doesn’t display them on the screen.

PCB Layout Editor

From the ‘view’menu, click ‘Board in 3D’ to see approximately what your finished board will look like

PCB Layout Editor

From the 3D Viewer, nodes can also be highlighted, in this example, VDD nodes are shown in red.

PCB Layout Editor

Displayed is a 3D view of the bottom of the board, also with VDD node highlighted.

Creating Gerber Files

Once the PCB layout is complete, the board manufacturer needs to know all the details of the board. Since there are many different PCB layout editors, a standard called ‘Gerber Files’ was created which is the format all PCB editors export to. The Gerber files are also usually very small and portable in size. From the Gerber files, and drill files, the manufacturer has enough knowledge to create your PCB board.

Gerber Files

From the file menu in the PCB editor, click fabrication outputs and then Gerber files.

Gerber Files

The ‘Gerber Setup’ will then open. The dialog box does a good job explaining the options.

Gerber Files

Under the Layers tab, any box that is checked will be created in a Gerber file. Check with the manufacturer, even if a layer is unused in your diagram, some manufacturers will still require the blank Gerber file for it.

Gerber Files

Check the following boxes under Drill Drawing Plots.

Gerber Files

Make sure Embedded apertures are selected from the list.

Gerber Files

If the Gerber files are successfully created, CAMtastic will open showing the files. Click the Camtastic tab in the bottom left and you can view layers independently.

Gerber Files

Now we need to export the Gerber files, follow the list shown below.

Gerber Files

Make sure to leave RS-274-X set like in the diagram to the right, then click ‘ok’

Gerber Files

You should get the last confirmation on the Gerber export. Export to a blank directory so you don’t forget to include any when you send them for fabrication

Finished Product

When all this is done, you will end up with a finished product.

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