40.3 Block Diagram
![](GUID-F530ABE6-0AFD-4038-A706-6355005BFF5B-low.png)
A mutual capacitance sensor is formed between two I/O lines - an X electrode for transmitting and Y electrode for sensing. The mutual capacitance between the X and Y electrode is measured by the peripheral touch controller.
![](GUID-4C5C1D6C-DAD2-4A1F-AF8B-E4C2649C1CB5-low.png)
![](GUID-78E697E1-5AD6-4DF1-B3CB-D7B0F4E4A153-low.png)
A self capacitance sensor is connected to a single pin on the peripheral touch controller through the Y electrode for sensing the signal. The sense electrode capacitance is measured by the peripheral touch controller.
![](GUID-D7BAC669-91AB-4D2B-A7AC-DDB445D24C58-low.png)
For more information about designing the touch sensor, refer to Buttons, Sliders and Wheels Touch Sensor Design Guide.