An example creating a 7400 multi section symbol

PCB123 Schematic Questions and Discussion.

An example creating a 7400 multi section symbol

    by Sal Hernandez » Mon May 14, 2012 9:30 am

Start by opening the Symbol Editor, go to Tools Symbol Editor. Select the Open Symbol button on the tool bar to load an existing symbol. If you do not want to use an existing symbol, you can begin drawing your symbol here. You will draw the body of your symbol in the shaded area provided using the polygon tools. Place you mouse near the edge or at a corner of the shaded area left click and hold, then move your mouse to change the size of the shaded area. The area will always be rectangular and the pins of your symbol will lie along the perimeter of this shape. You can use the Add Pin tool to add each terminal.

Starting with an existing symbol using the Open Symbol tool:

Search for the symbol you would like to start with in Step 1. Select the symbol in Step 2 and then select Load Symbol in Step 3.

If you would like to load an existing symbol to an additional section, use the Add Existing button. You can create a new blank section by selecting the Add New button. Use the Remove button to delete the selected section.

Once a new section is added, you see a tab labeled B and the pin numbers are updated. You can toggle between the tabs to edit each section.

Add section C by selecting Add Existing as described previously. You could also select Add New to create a blank section. Then copy the contents of section B in to the newly created section C. When you copy and paste into the new section you may need to adjust the shaded area to fit correctly around the symbol.

In section C, the copied pins are labeled seven, eight, and nine. In the 7400 pins, 7 and 14 are hidden so you must edit the pin numbers. Select the pins tab to edit the pin numbers.

Change the pin number for section C to eight, nine, and ten. Start by changing pin nine since duplicate pin numbers are not allowed.

Switch back to the Symbol tab and add Section D as described previously. Once you have all four sections of this symbol in place select, the pins tab to edit the pin properties and add the hidden pins.

On the pins tab modify the pin properties as shown below. You will add pin 7 by clicking in the first empty Number field and type a 7. Select the shape Hidden P/G type GND and change the Name. Repeat for pin 14. You can change the Section, Name, Number, Type and Shape of each pin. You can use the drop down menu for Section, Type and Shape. Double click in the Name and Number fields to edit. As you make changes to a pin, you can see the changes in the preview window. As changes are made on the pins tab, you can move pins as needed in the preview window.

After updating the information on the Pin Definitions tab, review each section and use the Save icon to save the symbol. Please save custom symbols to a new library. The libraries included with the PCB123 download should not be used to save your custom parts.

You can now go close the symbol editor and go to the Manage Parts tool to pair your symbol with a footprint and add to the taxonomy.

Click here for a complete series of Printed Circuit Board Layout Training Videos

Sal Hernandez
Software Support Engineer I
Sunstone Circuits
13626 S. Freeman Road
Mulino, OR 97042
Phone: 503-829-9108 x226
Fax: 503-829-5482
Sal Hernandez
Posts: 381
Joined: Wed Jul 06, 2011 12:00 am

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