ERC Warnings

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Bildschirmfoto 2024-04-24 um 21.15.29
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Hi to all!¨
There is another issue where I need your help. The ERC is showing 10 warnings. (see picture) Is tis critical for making the PCB becaus electrically I tested it and phisically it works on the breadboard.

your help is very appreciated.

best

Werni

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It’s only a warning.
If your circuit is sound, connecting tristate to output is no problem. But it’s very unusual. You should check your dircuit again, something’s no right.

Edit: your circuit is OK. I just noticed the hardwired direction signal (pin 1).

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ERC doesn’t understand circuits to find that you use bi-directional HC245 buffer permanently directed to one direction. It only sees that HC245 bi-directional pin is connected with always output pin pin so when bi-directional will be switched to this direction there will be conflict. May be it would be better to use one direction 3-state buffer (I don’t remember digital ICs symbols to suggest one).

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I’d go one step further than @Piotr.

The term “tri-state” can only be used on an “output” pin.
The Kicad library has no idea how this IC is to be connected in a circuit (because it can be bi-directional and tri-state), so all the data pins have been labeled as tri-state outputs.

Theoretically, in this case, the user should re-name all the A pins to “inputs” (because they are exclusively used as inputs) to satisfy ERC, but, the quick-fix (as others have suggested) is to ignore the warning. :grinning:

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Hi and thanks for your quick response i’m so thankful!
the best was to change the HC245 to a HC541 one direction buffer and it’s anyway better as I need it only in one direction.

best Werni

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