Creating Device Symbols and Libraries

Creating a New Library

• Right-click on the Parts palette’s parts list and select the “New Lib” command from the pop-up menu.
• Create a new library called “MyLib.clf” in the Libs directory.

Device library files hold collections of part symbols along with associated pin function information, default attribute values and external circuit references. A single library can contain from one to thousands of part definitions, to suit your needs.

Creating a Device Symbol

• Select New from the File menu
• In the “New” dialog select “Device Symbol”.

The Device Editor window contains a drawing area for your symbol, a tool palette and a pin list. The tool palette includes standard drawing tools plus special items for normal, inverted and bus pin placement.

• Click on the polygon () tool in the tool palette.
• Draw a symbol similar to the one shown (Note: double click on the last point to terminate polygon drawing).

• Select the () pin tool.
• Place input pins on the symbol by clicking at the positions shown.
• Select the () pin tool.
• Place an output pin as shown.

Note: The crossbar portion of the T pin tool only appears during placement and dragging for alignment purposes

• Return to the pointer () tool.
• Select the Part Attributes command from the Options menu. (Note: there will be no attributes in the list if there is no active design).
• Select the Part field in the list.
• Enter the value “LM741”.
• Select the Package field in the list.
• Enter the value “NAT8DPN” or other package code.
• Click the Done button.

These attribute values will appear as the defaults when this part is used on a schematic. If desired, these values can be overridden for each individual device.

Entering Pin Names and Numbers

• Double Click on the PIN1 item in the pin list and then type in the name “INA”.
• Click in the “Pin Number” text box and enter 2
• Double Click on the PIN2 item in the pin list and then type in the name “INB”.
• Click in the “Pin Number” text box and enter 3
• Double Click on the PIN3 item in the pin list and then type in the name “OUT”.
• Click in the “Pin Number” text box and enter 6
• Select “Output” in the Pin Function drop-down menu.

We have now entered default values for the pin numbers. These can be edited on the schematic for individual pins, if desired.

Saving and Using the Part

• Select the Save As command from the File menu.
• Enter the part name “LM741” or any other desired name.
• Click on the “MyLib.clf” library in the list to select a destination and press “Save”.
• Close the Device Editor.

If it is not already selected, select the “MyLib.clf” library in the drop-down library list in the Parts palette.

• If it is not already selected, select the “MyLib.clf” library in the drop-down library list in the Parts palette.
• Double-click on the newly-created part and place one in the schematic.

Auto-Creating a Symbol

For standard types of rectangular symbols, the Auto Create feature will generate a symbol for you in seconds.

• Select New from the File menu.
• In the “New” dialog select “Device Symbol”.
• Select the “Auto Create Symbol” command from the Options menu.
• In the Name box, enter “ALS374”, or any other desired symbol name.
• In the “Left Pins” box, enter the text “D7..0(9..2),,,CLK(1)”.

“D7..0” will generate a set of 8 pins named D7, D6, etc. “(9..2)” are the corresponding pin numbers. The three commas indicate that we want extra space between these pins. “CLK(1)” creates a single pin called CLK with pin number 1. The pin numbers can be omitted, if desired.

• In the “Right Pins” box, enter the text “Q7..0(12..19)”.
• Click on the Generate button.

The auto-generated symbol should now display the pins and pin numbers entered above. These items can be edited using the drawing tools and Pin Info dialog, if desired.

• Select the Save Part As item in the file menu and save the new part to the “MyLib.clf” library.
• Close the Device Editor window.

This completes the tutorial section “Device Symbol Editing”.