Qtouch Reference value following signal value

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I am running into an issue where my sliders reference values follow the corresponding signal values, thus I get no touch delta and no slider position.

I am running an ATMega328PB with PTC.

Any ideas? I am scratching my head on this one. 

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Perhaps the same like my problem:

https://community.atmel.com/forum...

Did you set maxonduration? Could you check if the error appeared after recalibration because of maxonduration?

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Hi Schwarz, 

 

I had kept Max on Duration at the default of 0, I just now tried 20 and 255 and it does not change anything. 

 

I am curious to know if anything has changed in terms of Qtouch project wizard or the default PTC settings in the last few months, my boards were working correctly in October 2016. 

 

 

 

schwarz wrote:

Perhaps the same like my problem:

https://community.atmel.com/forum...

Did you set maxonduration? Could you check if the error appeared after recalibration because of maxonduration?

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I'm having a similar issue with the AT42QT2120.  Working with individual keys (0-9) in comms mode using the atmega32u4. Keys 10 and 11 are designated as outputs for controlling LEDs.

 

Things that work fine:

--pressing any key by itself

--pressing any combination of keys simultaneously that doesn't include pressing key0

 

However, if a key (let's call it keyX for simplicity) is pressed simultaneously with key0, the reference value for keyX seems to follow keyX's signal value until key0 is no longer pressed (also worth noting key0's reference value also follows its signal value).  At that point, the reference value for keyX remains constant until either key0 is pressed again (at which point the reference value follows the signal value again), or a recalibration call is made.

 

Couple other things worth noting:

Once the reference value starts following the signal value, the key tends to stay in a detect state regardless of if the signal value is above or below the reference value.  The exception to this rule is if the reference value goes below 7000 or so, at which point that key will behave normally (though its reference value will no longer change with drift and such).

 

I contacted Digikey about the issue and they said they have no errata documentation for that chip.  Haven't gotten a hold of atmel directly yet.

 

Any help is very welcome :P

Last Edited: Tue. May 16, 2017 - 11:54 PM
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Hi, I think your issue might be related to saturation: I found the following FAQ when looking for a solution to our problem: https://microchip.secure.force.c...
It's on the Microchip website as they now own Atmel

 

By the way, it would be appreciated if anyone has some input for our issue: https://community.atmel.com/foru...

Cheers!