EE499 1998

In DOS, go to the subdirectory where your Orcad system is set up.
Enter cd ORCAD which brings you to the orcad directory.
Enter mkdir ABC where ABC (or what ever you want to call your design) will be the subdirectory AND the prefix of all your orcad design files. If you know what you are doing, you will copy a previous design and rename all file prefixes to ABC (must match the subdirectory name). This is what ORCAD refers to as a "design." If you don't know what you are doing, then just create the directory ABC.
Type Orcad and enter. Click and execute Design Management Tools (DMT).
Use the mouse to select the "design" in the left column and the schematic in the right column. This is where you can copy an old design and rename it into a new design. Try copying the tutor design to ABC if you want to try this. "Copy design" is at the bottom of the page and follow the instructions. Then exit the DMT
Renter the DMT but click on "configure ESP" instead of execute. Change the startup design to ABC and exit back to the main Orcad page.

Schematic Design Tool (SDT, version 1.20)

Initiate SDT: Use the mouse and click once on SDT. A window will open. Select execute.

NOTE: ORCAD menu windows are somewhat unique but make sense once you are familiar with them. The left mouse button, or enter, opens them. The right mouse button, or Esc key, closes a menu and will move you down the menu tree towards the original menu. You can access the menu options with a single letter (i.e., the upper case letter in each item), arrow keys to select, mouse to select and left mouse button to click or enter key to initiate.

Initiate Draft: Click on Draft. A screen will open. If your configuration should be set up for a default ABC.sch file to open, you will see that or you will need to open a file.

Open a schematic document: From the main menu, select quit...initialize. Enter the name of the file at the prompt and enter. You should see your schematic.

Getting and Placing a Part: From the main menu, you can either select get if you know the name of your part, or you can select library. Assume you want a library part, let's start by browsing. Select library...browse...all parts where you will see a listing of libraries. Select the library you think the part is in and forward through the parts. Select "get" to grab the part you want or right mouse button to return to the main screen. If you cannot find the part in the libraries, you will probably want to load different libraries in the SDT configuration (see Default library files). Worst case, you will need to create a library item (see manual). Having gotten the part, use the mouse to position your part and left button to place. Once all of that part type have been placed, use right mouse button to return to main menu.

Re-selecting a part for placement: Move the mouse arrow to touch the part you want to reposition. Open main menu and select block...move...begin...end...place. During this sequence, you will be able to move the part. Also, there will be an opportunity to rotate and mirror the part symbol. You can also use block to enclose several parts at once, by moving the mouse arrow between the begin and end selection.

Routing a wire: Use Place...wire...begin (click & drag to secure end point)...end (or new if you want to position another wire). A wire has two ends and possibly one corner but you can create complicated wire paths by clicking the "begin" once more for each corner you want to fix. DO NOT connect more than one wire to any location. DO NOT connect a wire to the center of another wire. Instead, place a junction and bring wires into it. Do not put a junction in the middle of a wire, it won't connect.

WARNING: DO NOT connect part leads directly together because the PCB layout will not be able to route any distance between the parts, it needs a wire connection.

Saving your schematic: From main menu select quit...update (or write). For a new file, enter name at prompt.

Quitting draft: From main menu select quit...abandon edits.

Annotate Schematic:After the schematic draft process you are ready to prepare your schematic for PCB layout. From here, all the programs should know that you are working on the ABC design. Annotation numbers your components. Once annotate is run you should see your chip numbers in the draft environment.

Update Field Contents: Use module "value" or field 8 which you configure in "local configuration" from Update Field Contents. You will also need to find a set of empty field slots in "configure schematic tools" and put an "8" in the "module value combine." Under draft, you can select edit to view the parameters for each component. You can manually set the part value, the reference number is set when you get the part from the library, the module number is set when you annotate. There are multiple fields that can contain module types. You can manually set the field type or you can automatically "stuff" the fields using aliases. Examples of aliasing can be found in *.stf files. You can find these files by the DOS command "dir *.stf /s" which will search for them. The module types are listed in PCBLIB.LST and MODULE.LST which can be read with an ascii editor. You can find MODULE.LST by using the DOS search command "dir module.lst /s." If you form a stuff file then you can configure "Update Field Contents" to use that file for the stuffing process. Try making your own stuff file, ABC.STF in subdirectory ABC. You may want to go back to draft and verify all components have been stuffed using the edit command. Example values are ck05 for small capacitors.

Create netlist: Select "create netlist" and click local configuration. There are 3 configuration files, INET, ILINK and IFORM,respectively. All of these should be toggled on. INET and ILINK should already have their local configurations automatically set. IFORM should have FEDIT.EXE selected in its configuration file. Initiate "Create netlist" and watch for errors. Your bound to make mistakes and if it is your first time, you have little chance of not getting errors here. You may gain confidence by trying the whole process with two capacitors tied in parallel. The good news is that if you generate a net list then there is a good chance that you have all your problems solved. However, some may leak through and you may spot them when you double check all your connections in PCB layout

To layout: Toggle all local configuration options to "off." Simply use this option to go straight to the PCB layout.

Default library files: under construction.

PCB layout

Under construction

PCB Production

1. Make negatives:

There are three types of negatives that you can make. The best is to take a positive, from a laser printer (don't use postscript because distortions may occur, use pcl and check your artwork for size distortion), to lithographer and have them make negatives using a photographic process. Your blacks will be completely opaque this way. The second way is to use a laser printer to print the negatives directly onto transparencies. Your blacks may not be as dark as you like and it is printer dependent. Our experience is the Lexmark and IBM printers seem to have more opaque blacks then do other printers such as HPs. Another way is to make your negatives on paper. We have had only one person successful at this approach but his results were excellent. If you use a laser printer to make negatives, you may have to mirror the images in order to get the emulsion to be against the board surface. Make sure your negatives have clear holes in the middle of all vias and pads (i.e., center punches for drilling).
Lines are opaque and space is transparent.
Top side should have emulsion down toward surface of board.
Bottom side should have emulsion up toward surface of board.
Attach one side to an "L" piece that is the same thickness as PCB. Then use the light table to accurately position and tape down the other side. Leave a half inch of space around edge.

2. Prepare raw PCB material:

Cut pieces and leave about a half inch around edge.
Peel off plastic covering on all surfaces and let dry in the dark for about 10 to 15 minutes. This apparently helps.

3. Expose PCB photo-resist to UV light:

Insert PCB into "L" piece/negatives.
Expose to 5 UV lamp system for 1.5 minutes per side. Don't shift PCB/"L" when flipping sides. You may have to let the board cool a few minutes because we have noticed the exposure changes due to heat.
Peel back negatives, if sticky use a plastic credit card type material, and remove PCB.

4. Develope PCB:

Run preheated (i.e., let warm up for about 20 minutes) developer on PCB until circuit lines are completely distinguishable from one another (i.e., start with 1.5 minutes but it will very with developer age, more than 10 minutes then mix new developer). If they are connected then do not try etching because the copper bridge will be very difficult to cut. As a last resort, if your lines are starting to come off, you can scrape bridges away to expose copper for etching.
Rinse in water rinse tank.

5. Etch PCB:

Etch until all copper is removed such that there are no copper bridges between lines. Check first couple minutes. If more than 15 minutes then you will want to add new etchant or mix new batch.
Rinse in water rinse tank.
Run PCB through roller system to dry.

6. Strip/Drill PCB:

If all center punch holes are etched then strip photoresist with stripper. Then drill. If center punches did not etch then drill first, then strip.
Cut excess PCB material from edges.

7. Mount components on PCB:

Mount vias.
Mount surface mount parts. Small items can be tacked with super glue then soldered with heat gun.
Mount pinned parts but be smart about it if you are doing double sided. That is, make sure your solder iron can access desired locations from the top.

FAQs