TSI and immunity problems under EN 61000-4-6

[luciano84]

Hi all,

I'm developing with kinetis KL family microcontrollers (KL36 and KL46) using TSI for drive a capacitive keyboard built with ITO technology.

The TSI is influenced under the EN 61000-4-6 immunity test and this cause false touch and release events and wrong behaviour.

I'm using TSI with TSS support (TSS version is 3.1.0) and as I said the target have a capacitive keyboard built with ITO technology.

I'm trying some configurations and under EN 61000-4-6 test the best results are setting "AFID key detector"; setting "AFID key detector" the problems with noise injected are partially resolved, but when I remove the noise the TSI don't detect any other touches.

Has anyone had the same problem and can help me?

Thanks,

Luciano

[mattiadell_oca]

Hi All,

I've just read your posts. I'm having same immunity problems: with a trick I'm able to avoid false touch but for most of the frequency range (2-20Mhz) capacitive touch doesn't work. For "doesn't work" I mean that wjen i put the finger on the pad the touch is not recognized.

In this 3 years have you found a better solution?

I'm using ML05Z32.

Best Regards,

Mattia

[vicentegomez]

Hi Luciano

Have you try to use different Nsamples values?

Also you can perform a recalibration after some times.

I do not know about your hardware, but you can check the application note  AN3863

Have a great day,

Vicente

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[luciano84]

Hi Pedro,

thanks for your reply. For the hardware we have followed the AN3863 that you have suggested me;

I've found a configuration that make me immune to noise (almost at every frequency) but this configuration seems be too strong in non noise condition and the TSI don't work; instead a configuration for non noise condition work very fine, but is not immune to noise.

The TSI parameters (as the presence or not of AFID filter for example) are configurables only setting the macros before build, is correct? Or is possible change it runtime?

There is a feedback from TSI that advise of the presence of noise?

From your experience is possible are completly immune under EN 61000-4-6 with this microcontroller family or with another family that use the same method of measurament?

Best regards,

Luciano