Newbie staring into the deep end of the pool w/ Cvpcb

Schematic Association (CvPCB)
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I am a newbie to kicad. I am trying to teach myself to make a single-sided through-hole PCB.

I am using this version of kicad:
Version 4.0.7+dfsg1-1-bpo9+1,release build
wxWidgets 3.0.2 Unicode and Boost 1.62.0
Platform: Linux4.16.0-0.bpo.2-amd64 x86_64, 64bit

In order to learn the kicad application programs and workflow needed to draw a schematic, assign footprints, and then layout the PCB, I followed
0yvind Nydal Dahl’s kicad video “Quickstart Intro to Kicad - Design a board in 5 minutes” at https://www.youtube.com/watch?reload=9&v=l9b_6WLemmg

It worked! The 3D-viewer is very, very nice. A great way to double-check that I laid out the PCB properly!

Next, I am starting to wonder if I can use kicad to do useful work – okay, honestly if I can teach myself to use it, so I started a new project to create a board using a 8-pin DIP 555 timer IC.

I went through the same steps outlined in 0yvind Nydal Dahl’s tutorial, and am having difficulty using Cvpcb to assign footprints to the 555 timer IC. I got footprints associated with all the other components, mainly passives and a relay.

I found that Kicad libraries are stored at /usr/share/kicad/library/
This linear library should have both the symbol and the footprint for the 555 timer IC i am using in my second circuit.

$ ls /usr/share/kicad/library/linear*
/usr/share/kicad/library/linear.dcm /usr/share/kicad/library/linear.lib

However, this library is not showing up in Cvpcb. What must I do in order to use the existing 555 footprint ? The 555 timer IC component appeared fine with all its eight pins in eeschema. But it’s a no-show in Cvpcb. I am using Cvpcb in the tabular input way as Dahl showed in his video.

I know there must be a one-to-one correspondence between each component in
my schematic and a kicad footprint file that matches in pin count and has a land pattern that corresponds to the physical component (which I can verify by pressing the [ View selected footprint ] button once I get a footprint file in the left-hand column).

But I don’t know why the standard 555 footprint isn’t showing up in Cvpcb ?

Can anybody guide me in making this footprint work?

I googled similar Cvpcb footprint issues but soon found myself looking into the deep-end of the pool – where I don’t belong!

Also, is there a way to save the Cvpcb footprint associations I have already made, so I don’t have to redo them in case my computer powers down unexpectedly?

Russ

2

My guess is you have the filter settings of cvpcb wrong. Have a look at this FAQ entry: How can i assign a footprint to a symbol?

What do you mean with standard 555 footprint. The 555 comes in many shapes and sizes (DIP, SOIC and even QFN/DFN)

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Hi Rene,

The 8-pin DIP through-hole package, commonly called" LM555"

$ grep -i 555 /usr/share/kicad/library/linear.lib

LM555

DEF LM555 U 0 20 Y Y 1 F N
F1 “LM555” 100 350 50 H V L CNN
ALIAS ICM7555 LMC555xM LMC555xMM LMC555xN TLC555CD TLC555CP TLC555CPS NA555 NE555 SE555 SA555

LMC555xTP

DEF LMC555xTP U 0 20 Y Y 1 F N
F1 “LMC555xTP” 100 350 50 H V L CNN

TLC555CPW

DEF TLC555CPW U 0 20 Y Y 1 F N
F1 “TLC555CPW” 100 350 50 H V L CNN
This shows me where the 555 is in the “linear” library. I just don’t know how to get Cvpcb to
“load” the associated footprint(s) that already exist for this IC so that I can see it.

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The linear library is a symbol library! you might need a refresher in what the difference between symbols and footprints is: What is the difference between footprints and symbols?

If you want a DIP package then you need to look in the Housings_DIP footprint library (in v5 it is called Package_DIP. The symbols in v5 also have a higher probability of having the correct footprint pre assigned. If this is a new project i would suggest you at least use the backport library to make future transfer to v5 easier. This would need manual installation however.)

You should still read the FAQ article i posted above.

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OOPS! My computer crashed due to an unrelated issue w/ the window manager in KDE Plasma.
After restarting it, however, I see all my associations for this new project in
Cvpcb are still there, except for the 555. Good!

Rene_Poschl, I read your two suggested pages, “What is the difference between footprints and symbols?”
and the FAQ entry, “How can i assign a footprint to a symbol?” Thank you.

If you want a DIP package then you need to look in the Housings_DIP footprint library (in v5 it is called Package_DIP. The symbols in v5 also have a higher probability of having the correct footprint pre assigned. If this is a new project i would suggest you at least use the backport library to make future transfer to v5 easier. This would need manual installation however.)

Yes, that is it! Thank you so much for clarifying that for me, Rene_Poschl. Now I understand, and have found the 8-pin land pattern (AKA footprint) I was looking for. Very good.

Thank you for taking time to help me. You have been a tremendous help, and I appreciate it.

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The Footprint does contain the land pattern. It can also include other information as well, including information on non-mechanical layers.

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