cancel
Showing results for 
Search instead for 
Did you mean: 

PSoC 5, 3 & 1 MCU

MaMi_1205306
Honored Contributor

Hi,

We are designing multiple CAPS buttons with PSoC 5LP.
When auto tuning was performed, only one button is set to be too sensitive than other buttons.

Cp is lower than other buttons because buttons with too high sensitivity are in the vicinity of the device.

And yet,

Resolution of one button: 16 bits
Resolution of other buttons: 13 to 14 bits

Why is such parameter setting done?

pastedImage_0.png

Is it correct to change the above "Sensitivity" parameter and adjust it?

0 Likes
Reply
1 Solution
ShanmathiN_06
Employee

Hi,

I assume that by design (hardware), certain sensors are more sensitive than others.

If the tuning is selected as auto, then the resolution is set for each sensor depending on the sensitivity parameter set in the CapSense customizer GUI.

So, answering to your question, yes, you are correct. You need to adjust the sensitivity according to the finger capacitance.

In other words, if you desire highly sensitive sensors (high resolution), then set the sensitivity value to a lower value and vice-versa.

You could refer to the CapSense component datasheet for more details on the sensitivity parameter. (https://www.cypress.com/documentation/component-datasheets/psoc-3psoc-5lp-capacitive-sensing-capsens... )

I hope this helps.

Thanks,

Shanmathi

View solution in original post

0 Likes
Reply
4 Replies
ShanmathiN_06
Employee

Hi,

I assume that by design (hardware), certain sensors are more sensitive than others.

If the tuning is selected as auto, then the resolution is set for each sensor depending on the sensitivity parameter set in the CapSense customizer GUI.

So, answering to your question, yes, you are correct. You need to adjust the sensitivity according to the finger capacitance.

In other words, if you desire highly sensitive sensors (high resolution), then set the sensitivity value to a lower value and vice-versa.

You could refer to the CapSense component datasheet for more details on the sensitivity parameter. (https://www.cypress.com/documentation/component-datasheets/psoc-3psoc-5lp-capacitive-sensing-capsens... )

I hope this helps.

Thanks,

Shanmathi

View solution in original post

0 Likes
Reply
MaMi_1205306
Honored Contributor

Shanmathi-san,

Thank you for your response.

I understood that fine adjustment is necessary with Sensitivity.

I think that autotuning determines parameters by measuring Cp,
We can not understand why only the closest sensor(with low Cp) is set to higher resolution than others.

Unlike other sensors, it reacts with floating fingers.

I think that the resolution should be set to a low value originally, but do you know the reason why it is set to a high value?

Regards,

Masashi

0 Likes
Reply
ShanmathiN_06
Employee

Hi Masashi-san,

I can understand your thoughts on this.

I speculate that the sensor close to IC is more sensitive to both noise and finger touches, due to lesser Cp. This maybe the reason for lesser SNR (if resolution is less) and auto-tune might have set the resolution to a higher value to increase SNR.

Thanks,

Shanmathi

0 Likes
Reply
MaMi_1205306
Honored Contributor

Shanmathi-san,

I had no understanding that it would be sensitive to noise as well.
I appreciate reasonable explanation.

Regards,

Masashi

0 Likes
Reply