Creating a multi part component with different symbols per unit

The component I want to create is a MC14572 which has 4 inverters, 1 NAND and 1 NOR gate in a single package.

Is there a way to create this as a component so I can use the gates individually, or is my only option to lump them together in a single part? At the moment I can add or remove different pins to an individual part, but if I change the lines etc it affects all parts.


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Yes. There is a multi-unit option. Like anything it has a learning curve. There is a setting for making things appear in one part only that you have to pay attention too. Otherwise, you end up making a change on one thing and it affects them all. I didn’t find it intuitive at first.

I think you have to choose the multi unit part at the initial setup screen. Been a few months since I’ve done it so I don’t exactly remember the steps.

You might choose something like an opamp that is multi unit as a guide line or just change it to suit your needs and rename it.

Just for fun, I created a symbol using a symgen script.

MC14572.lib (2.2 KB)
MC14572.dcm (168 Bytes)

mc14572.htm (178.7 KB)

Firstly, thanks Bobc for the part, at least I can get on with my schematic now :+1:

I should’ve said, I’m OK with creating multi-part components in general. It’s just making the individual parts different that I can’t seem to find a way to do. The only component property that could allow this as far as I can see is “All units are not interchangeable” but that doesn’t seem to make a difference - if I create a gate in Unit A the same gate is present for all the other units. If switch to Unit B and add or remove a line for example, the change affects all the others.

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It is a little tricky. Each pin or graphic has a property “Common to all units in component”. When you place a pin, you can set it in the dialog. For graphics, you need to edit the properties after placing it. I think the property defaults to whatever you last selected.


Ah that’s the bit I was missing, thank you.

Whether I check or un-check the box that says “common to all units in symbol” it does not seem to make a difference - the pin appears in both symbols. When I add a pin to one symbol it gets added to the other. This is not what I want to happen, and I don’t see a way to make the pins in each schematic separate, other than this checkbox which appears not to work. Is this a bug?

Don’t know what version you are using, but here is a direct link to the tutorial for making a symbol from scratch in the FAQ for multi-unit symbols. This example has 3 gates, one with different pin-count and geometry.

Hopefully this tutorial shows you the small, insignificant step that you forgot that makes all the difference in the world. :wink: