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Schmitt Buffer/Trigger with Encoder and buttons - Inverting...

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elcrni:
hi all,

In a middle of a PCB design and wanted to make things proper with my buttons and rotary encoder. So apart from RC filter, i would also like to include Schmitt Triger for a proper signal of the encoder and buttons.
After researching the matter for a bit, i am still a little confused on "inverting" Schmitt Triger.

My schematic looks like this, except i use 10k resistors and 1uF tantalum caps:



So a few questions:

1. I would like to convert (end debounce) signal from encoder and buttons, so i was thinking of getting this one:
74HC14D
However, this one says "inverter", and i am aware that i can also get inverted signal output, but here i need non inverted signal. So the question is, would this one work for my case?
2. If i do have inverted signal, would that mean simply swapping the contacts on the switch to work as non inverting?
3. 74HC14 has 6 IN/OUT pins, can i use 2 pins for encoder and remaining 4 for 4 buttons? All on one IC? Or is it better to separate for whatever reason?
4. I can use 74HC14 for mechanical toggle switches as well? I see no reason why not.

Many thanks in advance,
Alek

Zero999:
There are non-inverting Schmitt trigger ICs such as the, 74HC2G17 and 74HC7014, or use two 74HC14 in series to get non-inverting.

Is this going to a microcontroller? If so, check it has Schmitt trigger inputs, then you don't need the 74HC14. Another thing to consider is doing the de-bouncing in software, so no additional components are required.

elcrni:
Thanks Zero999,

Yes, the signal is going to Arduino Mega, i am not sure it has Schmitt input as such.
Also, i would like to avoid software debouncing as my code is decoding radio signals so i would like to keep it as light as possible.

Many thanks,
Alek

P.S. i can use both encoder and switches on the same 74HC14 IC at the same time?

elcrni:
also, if i am using inverting Schmitt IC, i could simply tell in the code that HIGH is LOW and vice versa?

I have found this one though:
https://www.mouser.at/ProductDetail/771-HC7014D112

Many thanks,
Alek

MarkF:
It's really not going to matter if the encoder lines are inverted or not.
Just so you do the same to BOTH lines.

You could invert them back in either software or hardware if you like.

The bigger issue I see it that you're not using a RC filter.
Just the capacitor.
The problem is that the encoder switches will present a short across the capacitors when they close.
Creating a non-current limited discharge.  Thus, reducing the life of the encoder contacts.
Use the full RC filtering as shown in some datasheets (i.e. PEC11 encoder datasheet for example).


Edit:
  Also 1uF capacitors are pretty large (slowing down the rotation response.
  I've found 10nF to 47nF range the best choice with the 10K resistors.

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