- Creating Device Symbols
This tutorial will show you how to use the symbol editor tool to create your own device symbols.
Creating a New Library
library files hold collections of device symbols along with associated
pin function information, default attribute values, and
internal-circuit definitions. A single library can contain from one to
thousands of part definitions, as suits your application.
- Using the right mouse button, click on the Parts Palette. Select the New Lib command in the pop-up menu.
- Create a new library called mylib.clf in the LogicWorks directory or any other convenient location.
Creating a Device Symbol
- Click on the New Document()
button in the toolbar. Then select Device Symbol and click the OK
button. A new device symbol editor window and the associated toolbars
symbol editor window contains a drawing area for your symbol, plus a
toolbar and a Pin Name List. The toolbar includes standard drawing
tools as well as special items for normal and bus pin placement.
Setting Pin Name Visibility
default, the symbol editor displays the name of each pin next to the
pin stub. For this example, we want to turn this off. To do this:
Setting items in the Properties command with no objects selected sets the default properties when future objects are created.
- Make sure no graphic items are selected in the drawing area, and then select the Properties command in the Objects menu.
- Click on the Pin tab, and turn off the Visible switch in the Pin Name area.
- Click the OK button.
Drawing the Symbol
The position of the symbol in this window is not important.
- Click on the polygon () tool in the toolbar.
a symbol similar to the one shown in the next diagram by clicking once
at each corner point and then double-clicking to terminate the polygon.
Note: The crossbar portion of the pin tool appears only during placement and dragging, for alignment purposes.
- Select the pin () tool.
- Place input pins on the symbol by clicking at the position shown in the next diagram.
- Select the pin () tool.
- Place an output pin as shown:
Entering Pin Names and Numbers
the pin graphics on the symbol causes pin names to be added
automatically to the pin list. In this section, we will enter more
meaningful names and add pin numbers.
- Double-click on the PIN1 item in the pin list. This will open the name for editing.
- Type the new name INA, and then press the Enter key.
- Click in the Pin Number box and type 2:
- Similarly, select the PIN2 item, enter the pin number 3, and change the name to INB.
- Enter the part name LM741 or any other desired name.
on the mylib.clf library(create it if it does not exist with New Lib)
in the list in order to select the destination.
- Close the symbol editor window
- If mylib.clf is not already selected, select it in the library drop-down list in the Parts Palette.
- Drag the newly created part, and place a copy of it in the schematic. The result should appear as follows:
Autocreating a Symbol
For standard types of rectangular symbols, the Autocreate feature will generate a symbol for you in seconds.
- Click on the New Document () button in the toolbar, and then double-click on Device Symbol.
- Select the Auto Create Symbol command in the Options Menu.
- Make sure that the Show Pin Names on Symbol switch is on.
- In the Left Pin box, type the text D7..0(9..2),,,CLK(1):
entry D7..0 will generate a set of eight pins named D7, D6,etc. (9..2)
refers to the corresponding pin numbers. The three commas indicate that
we want extra space between these pins. Finally, CLK(1) creates a
single pin called CLK with pin number 1. The pin numbers can be omitted
, if desired.
The autogenerated symbol should now display the pins and pin numbers entered previously.
- In the Right Pins Box, type the text Q7..0(12..19).
- In the Name box in the centre, type ALS374, or any other desired symbol name.
- If it is not already, turn on the Show Pin Names on the Symbol switch.
- Click the generate button.
These items can be edited using the drawing tools and Pin Info box, if desired.
The symbol can now be placed in a schematic in the usual manner.
- Save the new part to the mylib.clf library as described earlier.
- Close the symbol editor window.