FDC2214EVM: Mutual capacitance and Self capacitance

Ryoji Itoh

Part Number: FDC2214EVM
Other Parts Discussed in Thread: FDC2214

Please tell us whether mutual capacity is worked by using GUI.
I would appreciate it if you could answer based on the following two points.

・ Is it possible to change the self capacity and mutual capacity by changing the register in GUI?
・ Is the initial setting the mutual capacity method?

Best regards,
Ryoji Ito

over 5 years ago

0 Kristin Jones93 over 5 years ago

TI__Genius 17440 points

Hello Ryoji,

Are you referring to mutual capacitance and self capacitance as described in the "Design" section of this Wikipedia article on capacitive sensing? The article states, "There are two types of capacitive sensing system: mutual capacitance,^[5] where the object (finger, conductive stylus) alters the mutual coupling between row and column electrodes, which are scanned sequentially;^[6] and self- or absolute capacitance where the object (such as a finger) loads the sensor or increases the parasitic capacitance to ground." For this definition, the FDC2214 measures self capacitance. There is no way to change this.

Please note that what the FDC2214 really measures the resonant frequency of the LC tank sensor, and the change in capacitance can be derived from the measured change in sensor frequency. The sensor capacitance is not directly measured.

Best Regards,

Sensors

Sensors forum

FDC2214EVM: Mutual capacitance and Self capacitance