Qtouch charge share delay value?

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I'm going through the app note for the touch solutions and on page 6 it says the following:

"The value of Rs should typically be within the range of 1kΩ to 10kΩ. If Rs is increased the value of Charge Share Delay (CSD) will need to be increased appropriately to ensure complete charging of Cx"

Which is fine, however next line says:

"Increase Rs in steps up to 100kΩ to improve performance in noisy environments. In extreme cases higher values of Rs, going up to 1MΩ may be required."

 

OK so if the value should range between 1 and 255 for a full scale of 1k to 10k, what happens for larger values? Does the application really requires the value to be around max as R approaches 100k?

How does the cap value fit into this?

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Qtouch is a bit of a dark art.  I used to have a QT600 and gave that away to Johan I think.  NOwadays you can buy touch IC's with all this figured out already.

 

At the risk of getting tossed outta here, I dare say I used a competitors product a couple of times and used their touch sense input capabilities and it was remarkably pleasant to get going.

 

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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Without going against "the family", how is the MTCH102?

I'm talking reliability and easy of designing for without too many iterations?

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slow_rider wrote:
Without going against "the family", how is the MTCH102?

 

I could not tell you as I have not used them.  But they have an evaluation kit that might be worth a try at $30usd.  I did not get to deep into the documentation though

 

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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Thanks. I just ordered one from Arrow. Wish they had some more written information about DM160229 on MC's website.