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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.)
Adding Libraries (Cont.)
Since most of us are using Microchip PIC microcontrollers, add the Microchip library
Adding Libraries (Cont.)
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
Adding Libraries (Cont.)
From the Library folder, go to the PCB folder, this folder contains PCB footprint libraries.
Adding Libraries (Cont.)
From the PCB folder, add Chip CapacitorChip ResistorCrystal OscillatorResistor- Axial
Adding Libraries (Cont.)
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.
Schematic Layout- Placing Parts
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.
Schematic Layout- Placing Parts
From the ‘Libraries’drop down box, look for the Microchip Microcontroller library we added earlier.
Schematic Layout- Placing Parts
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
Schematic Layout- Placing Parts
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.
Schematic Layout- Placing Parts
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
Schematic Layout- Placing Parts
Which to choose? That’s up to you! But for this tutorial, lets use a DIP package
Schematic Layout- Placing Parts
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.
Schematic Layout- Placing Parts
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.
Creating Custom Parts
From the file menu, create a new schematic library, and a new PCB library. Save these libraries under a name you will remember.
Creating Custom Parts
Select/Highlight the schematic library you just created and click ‘SCH Library’ in the bottom corner of the project menu
Creating Custom Parts
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.
Creating Custom Parts
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
Creating Custom Parts
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
Creating Custom Parts
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.
Creating Custom Parts
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.
Creating Custom Parts
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
Creating Custom Parts
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
Creating Custom Parts
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.
Creating Custom Parts
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).
Creating Custom Parts
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.
Creating Custom Parts
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)
Creating Custom Parts
Now we need to label the pads, click the ‘Place String’ icon
Creating Custom Parts
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
Creating Custom Parts
Our spacing and text choices do not allow us to place the text horizontal, so we must resize the box and rotate the text.
Creating Custom Parts
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.
Creating Custom Parts
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.
Creating Custom Parts
From the PCB Model popup box, click ‘browse’
Creating Custom Parts
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
Creating Custom Parts
This should bring you back to the model page, where you can verify the footprint choice you made
Creating Custom Parts
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.