# LTSPICE 74HC library (from Yahoo LTSpice group)

#### djsfantasi

Joined Apr 11, 2010
7,917
I have downloaded the 74HC library from the Yahoo group and can see it in LTSpice, but when I try to use the components, I get the following error? Can anyone tell me what I am doing wrong?

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Joined Jun 1, 2009
499
You didn't include the required subcircuits you just loaded the symbols. You have to include whatever .sub or equivalent file that came with it. Create a new spice directive and use a .include statement that contains the location of the file that has the information
Symbols are just graphics with labels, it doesn't contain the spice information for the actual model that's what the sub circuit is for.

Do you really need to simulate the 74HC series? The behavioral logic models that come with LTSpice simulate incredibly fast and are generally fine as long as you're not working near the edge of speed limits or ultra fine timing.

#### SgtWookie

Joined Jul 17, 2007
22,221
On the LTSpice toolbar, on the far right, click on the .sp icon.

In the box, type:
Rich (BB code):
.inc 74hc.lib
Then click the OK button, and drop the line of text near your .tran statement (it can be anywhere in the schematic, but I usually put .inc statements near the .tran statement.)

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#### djsfantasi

Joined Apr 11, 2010
7,917
Thanks Sgt. That worked!

@sceadwian, I want to use some of the advanced 74hc ICs, such as the universal up/down counter...

Joined Jun 1, 2009
499
<razz> at Wooikie, cause that's the same thing I said to do =)

#### SgtWookie

Joined Jul 17, 2007
22,221
<razz> at Wooikie, cause that's the same thing I said to do =)
Yeah, I know. You 'splained what he needed. I 'splained how to do it though.

#### djsfantasi

Joined Apr 11, 2010
7,917
What Wookie said...

You didn't include the required subcircuits you just loaded the symbols.
Poor communication on my part. This didn't provide me with any new information, as I already understood this part, and I didn't make that clear in my post.

Joined Jun 1, 2009
499
Sorry djs, I have a horrible crippling assumption that everyone I respond to has actually read the help files for the software they're using =) It's easy to forget just how uncommon this actually is.

It's a personal failing of mine I'll likely never gain much ground in combating, I tend to supply to much information and not enough 'how to' then again I learn a little differently than most people.

#### Ron H

Joined Apr 14, 2005
7,014
I think Wookie has a very special knack for understanding the experience level of the person he is attempting to help, not to mention the patience of Job.