Using LogicWorks

Here are some potential solutions to problems that other CS 231 students have encountered with LogicWorks during the previous semesters. Some of these were problems with earlier versions of LogicWorks.

• Accessing LogicWorks
• Show window contents while dragging
• Saving your files
• Printing
• Binary probes show Z, X or C
• Devices don't have the number of inputs you need
• LogicWorks seems to hang
• Moving and resizing LogicWorks windows

In addition, you can check out the LogicWorks 3 FAQ and the LogicWorks 4 FAQ (for anyone who owns the program) maintained by the developer, Capilano Computing.

Accessing LogicWorks

LogicWorks is available in the Windows XP lab in L416 DCL and 406B8 and 406B1 Engineering Hall.

The lab machines were recently upgraded to Windows XP. Passwords are maintained on a campus-wide Active Directory server. If you haven't already, you'll need to go to the Active Directory server to set your password or "unlock" your account. More information about this is available from the labsitters.

If you would like to buy LogicWorks for your home machine, please see the Capilano Computing home page; Windows and Mac versions are available.

Show window contents while dragging

When you start up LogicWorks in Windows XP, you may get an error message that tells you to turn off the "Show window contents while dragging" option. You'll have to right-click in the Windows XP desktop background, select "Properties," choose the "Effects" tab, and unclick "Show window contents while dragging."

Saving your files

You can either save your circuit files to a floppy disk (not recommended) or the CSIL Unix machines file system. For the latter, you will need to "map" the Unix file system to the Windows XP machines. Open "My Computer" and choose "Map Network Drive..." from the "Tools" menu. In the "Folder" drop-down box, type

\\csil-server1\netid

Printing

Getting LogicWorks diagrams to print correctly on one page can be tricky. First, turn on "Show Printed Page Breaks" under the Schematic -> Design Preferences menu, so you can see the page borders in magenta. Then try the Schematic -> Center In Page option. Finally, you can shrink the diagram by using Print Options under the File menu. But don't make the circuit so small that it's unreadable!

One suggestion from a student is to take advantage of the "Pages X to Y" option in the Print dialog box. Make sure that your circuit fits entirely in the first n pages, and then print from Page 1 to n. (Some of the larger assignments might take 2 pages or so.) Otherwise, even though the circuit fits on one sheet, LogicWorks likes to print all the adjacent blank pages.

The printers in the lab cost money. Worse, LogicWorks is only available on those machines, and LogicWorks diagrams can't be saved in any portable format. If you want to print your diagrams elsewhere, your best bet is probably to "Cut" the diagram out of LogicWorks and "Paste" it into another application, such as Word or PowerPoint, which are both available in the lab.

The printers in the EWS labs won't print your circuit immediately after you select "Print". In order to print, go to the desktop and open "Print Job Browser." Select the printer that you sent the job to. You should be able to see the job next to your user name. Highlight it and hit "Print" on the bottom bar to print.

Students have been having trouble getting some EWS machines to print at all, as Logicworks crashes when they try. The only suggestions we have at this time are to either save your file and move to a different machine, talk to the lab operator about it, or if necessary, take a screenshot of your circuit (Alt+PrintScreen) and print the image file.

Binary probes show Z, X or C

When the LogicWorks simulator can't figure out the value of a signal line, the binary probes will output:

• Z if there is nothing connected to that line
• X if it doesn't know what the value should be (e.g., you haven't specified both inputs for an AND gate, and probe the AND output.)
• C if there are two lines with different values connected together

So make sure that all of your wiring is correct. (Checking it is easier if your diagram is neat!) Some common problems that you should look for include:

• Your wires or devices might accidentally overlap one another, in which case it could appear as if two things are connected when they really aren't.
• Make sure the wires are actually connected to the pins of your AND, OR and NOT gates.
• Whenever a wire splits into two branches, there will be a dot at the intersection. If there is no dot, then the line wasn't split.
• If you are naming your signal lines, make sure the names appear in that ugly pink color. If not, then it's just plain text, not a signal name.
• Make sure that you do not assign the same name to two different lines.

You can also use the signal probe tool in the Tool Palette (there's a question mark in it) to see the values on individual lines. This can help you figure out what is properly connected and what isn't.

Devices don't have the number of inputs you need

Most of the basic gates and devices in logic design can be generalized with respect to the number of inputs and outputs. For example, you can have decoders of various sizes, or primitive gates with any number of inputs (theoretically). LogicWorks has a much more limited selection of parts, but there are many ways of dealing with this.

For instance, LogicWorks doesn't have a six-input OR gate (u+v+w+x+y+z). Two alternatives are:

1. Use several smaller gates instead. You might implement the operation as (u+v+w) + (x+y+z) instead, with two 3-input OR gates and one 2-input OR gate.
2. Use a larger gate instead. LogicWorks does provide an eight-input OR gate, and thanks to Boolean algebra we know that u+v+w+x+y+z is the same as u+v+w+x+y+z+0+0.

LogicWorks seems to hang

If your circuit doesn't seem to be running (for example, you can't flip your binary switches or change inputs on the hex keyboards), then make sure that the simulator is running. Select "Simulator" from the Tools menu in the main LogicWorks window, and click Run.

If your entire machine seems to have stopped, then see the section on moving and resizing windows.

Moving and resizing LogicWorks windows

This doesn't appear to be a problem anymore since the lab machines were upgraded with LogicWorks 3.0.3, but just in case it happens to someone: To move or resize LogicWorks windows, you might need to hold down a key (it's usually convenient to use the Shift, Control or Alt keys) as you drag the mouse. If you forget to hold down a key, then your entire machine will appear frozen until you do press something.