Unable to understand TSC connections in STM32WB

[GShai]

Hi Sir/Madam,

The Sensor Capacitor (Cx) is not connected in the below mentioned. Can you please provide clarity on the Cx connection with MCU.

1. While configuring the shielding in TSC using STM32CubeMX, it is asking to configure Cs(Sampling Capacitor) in the same group. In the above mentioned figure, i didn't find. If it is need to be connected, please provide a reference. Its really helps me a lot
2. Is RsShield connected in parallel to the all the touch keys?

Please find the STM32CubeMx image regarding 1st point.

Thanks & Regards,

[OlivierR]

Regarding 1, you just need to select an IO for Sampling capacitor.

Regarding 2, No Rshield is between the Shield IO (G1_IO1 in your case) and the copper shield.

Rgds

[OlivierR · Accepted solution]

Find an example based on 6 sensors + shield

A) Regarding the STM32CubeMx project:

B) Regarding schematics:

C) Regarding application

ioc, main.c and interrupt files are attached.

[GShai]

Hi SIr/Madam,

Greeting of the day,

In the above reply, i understand these points.

1. G1_IO3 is configured as Shielding (as per the CubeMx image) , G1_IO4 is configured as Sampling. The CsShield is connected the G1_IO4.
2. Cx(Sensor Capacitor) is not required in this design.
3. RsShield is connected to G1_IO3(configured as Shielding as per the CubeMx image) ,whereas RsShield is connected to the all the keys in parallel from the bottom layer.

It will be really helpful for me if give me clarity on this.

Thanks & Regards,

[OlivierR]

1. yes
2. Cx, or sensor capacitance not capacitor. This is not a real component. Cx represent sensor capacitance with respect to the ground: Conductive (Copper), dielectric (FR4), .... Usually few pF.
3. The shield is never connected to keys.

Find a schematics bellow from layout point of view:

[gousebasha shaik]

Thank you,

I will go forward with these inputs.

Thank you very much for your valuable efforts.