Series resistor when using weak pull-up

[Sharky]

The touchpad that is connected to the board have 1.5 metre of cable.

I have only used the capacitors and the serie resistors for products that needed
to have an approval.

But if I understand you right you also mean that the software debouncing will do the job.
I think that I will just try to make the board without capacitors and serie resistors on the input's and see what happen when it goes to approval.

Sharky

[mister_e]

So in this case don't use the internal weak up. Use 1K-4.7 K instead. Safer.

It's a long debate...'to use or not to use internal pull-up?'

[Sharky]

I have used pull-ups up to 100 K without problems.

I know that you don't like weak pull-ups I remember from one of my other thread's, but I would really like do know what the problem about them should be?

Because I really can see myself save some space on my PCB if I use the WPU's
but if it is to risky I will of course not use them, I would just like to know why I
should not use them!

I have read that Melanie often use them even in industrial applications and I must admit that a lady that have a catsuit gives even a Shark some respect!

Sharky

[sayzer]

...and who is being the Shark here, I really wonder?


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[mister_e]

so you should know a part of the story. I had some issue in car application, after i switch for external one i nerver ever had issue... this is why.

BUT if it works for you... use it.

Also, don't forget, if the unit is not always powered.... there's no pull-up, those pins comes 'floating' ...

But i'm from the old school. I have my own fear that some don't have.