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Topic: Quick question about using a simple toggle switch (Read 250 times) previous topic - next topic

Jimmy60

I want to enable selecting between two different modes in my project. Basically one is a long period and the other is shorter. I want to use a simple spst switch on a digital pin with the internal pullup resistors. This works well because it will keep the correct mode even if reset.

I have a slight concern about leaving the switch on all the time. Is that a potential problem?

I think it's probably a non-issue but I'm experienced enough to know that assuming things is less reliable than checking with people who know better.


retrolefty


I want to enable selecting between two different modes in my project. Basically one is a long period and the other is shorter. I want to use a simple spst switch on a digital pin with the internal pullup resistors. This works well because it will keep the correct mode even if reset.

I have a slight concern about leaving the switch on all the time. Is that a potential problem?

I think it's probably a non-issue but I'm experienced enough to know that assuming things is less reliable than checking with people who know better.

It's a non-issue, just microamps flow if the switch is closed with the internal pull-up enabled, and no current flow if the switch is open.

Lefty



DVDdoug

That's no problem at all!

With the switch on and the input pulled to ground, there is a small current through the internal pull-up resistor.

Of course if the switch is on 90% of the time, you can reverse your logic  and make "off" the "normal" condition.    But as far as reliability, it doesn't matter.

Jimmy60

Thanks guys. That's what I thought but now it isn't an assumption.

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