ATmega328PB with integrated Qtouch vs. Qtouch support via library

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I'm about to start my first project involving touch sensing, I've noticed that the only non-SAM device that has hardware support for touch is the ATmega328PB (according to Atmel's website). As one might expect it's not the perfect candidate for my application but I can not find a comparison between it and the all-software Qtouch support which is offered for virtually any AVR.

 

I'm mainly interested in response time, debugging capability through Studio, RAM & code space usage and CPU load. 

If someone has some experience or knowledge about these - do share. Thanks!

Last Edited: Sun. Oct 1, 2017 - 04:34 PM
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There is also ATmega324PB (if you can get your hands on it). It was quite a while ago when I used an all-software library. I didn't like it. Therefore, if I had to do it again, I would try to pick a micro with PTC. Don't remember RAM & code space usage ... I think the PTC one eats more code space. But maybe that is because I used a more recent and therefore, more bloated, version. I didn't use any special debugging features, therefore, no comment there. CPU load - one of the things I remember about the all-software library is that in some cases it would get stuck in a call for a really long time, like hundredth of milliseconds. Didn't see anything like that with the PTC version.

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ATMEGA328PB is nice, but use the QFN package (look at availability on octopart).

 

When in the dark remember-the future looks brighter than ever.

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Why QFN?

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Did you look at octopart?  The TQFP  has not been avail since around June...but they will be returning by December.  There are a couple of suppliers (about 2 or 3 out of 12) with QFN parts in stock today.

Someone layed out their board to accept either style (QFN footprint inside TQPFP).

When in the dark remember-the future looks brighter than ever.

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I've checked for ATMEGA328PB stock and no one has them in TQFP package. Digikey lead is 10 weeks. I don't know if I want to get involved with such a device. It's a shame that Atmel does not incorporate the touch hardware into more Mega & Xmega devices. Having just a couple of devices does not help with popularity for the platform.