Author Topic: design check in Kicad  (Read 1886 times)

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Offline Wawavoun

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design check in Kicad
« on: July 26, 2021, 05:03:21 pm »
Hello there !

I start to learn Kicad since one week and I have discover a very very good tool !
It is perfectly usable after a very short reading of a tutorial. So I like them !

Now my question :
I frequently use ic's with logic gates (74LS etc...).
In the schematics is there a way to check if some ic's are not powered (for example if I forgot the E part of a 74ls00) ?
Is there a way to know if some parts of some ic's are not in use (and then sometime inputs need to be grounded) ? 

If have made tests and the 'standard check' in schematics is not watchful about that...

At the moment I check that in pcbnew but it is not very comfortable and it is unsure...

Many thanks, regards.
Philippe
« Last Edit: July 26, 2021, 05:20:45 pm by Wawavoun »
 

Online retiredfeline

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Re: design check in Kicad
« Reply #1 on: July 26, 2021, 10:03:52 pm »
If you do an ERC in eeschema it should complain if the power pin is not driven. This is providing the symbol had given the power pin the Power In attribute which should be the case with the library symbols.
 

Offline mf_ibfeew

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Re: design check in Kicad
« Reply #2 on: July 26, 2021, 11:31:49 pm »
>If you do an ERC in eeschema it should complain if the power pin is not driven.
>This is providing the symbol had given the power pin the Power In attribute which should be the case with the library symbols.
The problem is not the unconnected power pin (as you write the ERC will detect this), the problem is a "forgotten" unit of a multi-part-symbol, especially a forgotten power unit.

@ Wawavoun:
I have also found this problem (with the actual version Kicad 5.99) and I also found no good solution.

I quick search on the gitlab-bugtracker showed that other users already placed an feature-request for ERC-enhancing (#1922/#8535), so this check for unused units (of multi-unit-symbols) might be implemented in the future.
 

Online ebastler

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Re: design check in Kicad
« Reply #3 on: July 27, 2021, 05:31:16 pm »
Ouch, I had not realized that the ERC does not check for this! Must have got lucky and never forgotten a power "gate" so far.

This is quite annoying, since it overlooks an error which is somewhat easy to make, and will result in a non-working PCB. (Well, at least it will typically be fixable with bodge wires...) Too bad that this apparently did not make the cut for 6.0, given that the problem persists in 5.99.
 
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