Self and Mutual capacitance at the same time

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
GiTr_282596
Level 2
Level 2
10 replies posted 5 replies posted 5 questions asked

Hello everyone,

this case of mine is just to a feasibility / pre-design stage, anyway:

I have a capacitive application involving a trackpad and some single capacitive buttons, to use in a harsh environment.

In order to reduce the population of pins, and to have a smaller tail in the sensing FPC, I was minding to use a mutual-capacitive configuration.

As far as I know the mutual-capacitance is less sensitive to noise with respect to self-capacitance.

My wonder is: in order to get a robust system, is it possible to use the same CSD component to scan the keys with the self-capacitance technique (I will sense the Rows and the Columns, of course) and then switch to mutual-capacitance to identify where the touch is?

And, over all, does this make sense?

Thank you very much in advance

GianLuca

0 Likes
1 Solution
AchimE_41
Employee
Employee
10 sign-ins 5 sign-ins First comment on KBA

Hi GianLuca,

Yes this is possible. Instead of assigning a new pin (dedicated) to the CSD button you have to assign the CSX pin to it in the CapSense config. Or vice versa.

pastedImage_0.png

There are areas where it makes sense to combine both technologies and use both of their strength.

View solution in original post

2 Replies
AchimE_41
Employee
Employee
10 sign-ins 5 sign-ins First comment on KBA

Hi GianLuca,

Yes this is possible. Instead of assigning a new pin (dedicated) to the CSD button you have to assign the CSX pin to it in the CapSense config. Or vice versa.

pastedImage_0.png

There are areas where it makes sense to combine both technologies and use both of their strength.

Oh ok, I see.

Thank you very much aceh!

This solves 🙂

GianLuca

0 Likes