Generate Mutual Cap Boost Mode Project

Last modified by Microchip on 2023/11/10 11:18


Mutual Capacitance Button

Create a User Board project for Mutualcap technology from Sensors > Button > Technology > Mutualcap from within the QTouch® Configurator. (Refer to the "Generate a QTouch Configurator Project" page for more details.)

QTouch Configurator with all six mutual-cap buttons being added

Sensor Layout View

Screenshot of Configurator with 6 buttons added

Enabling Boost Mode

After configuring the sensors and pins, to enable Boost Mode, select the Boost Mode checkbox.

Screenshot of Configurator with Boost Mode enabled

Pin Selection View

Screenshot of Pin selection in Configurator

The mutual capacitance sensors are grouped down as per the Y-lines. If the total number of sensors for a given Y line is more than four, multiple groups are formed with four X-lines for each group. The group information can be found in touch.h file as illustrated below.

For a given Y line, if the number of sensors is less than four or if the number of sensors is not a multiple of four, virtual sensors named X_NONE are added to the group in that Y-line.

In the above example configuration, Y0 will not have X_NONE and the Y2 group will have two X_NONE as shown below.

Screenshot of Touch.h showing group parameter settings

The acquisition parameters (like filter level, prescaler, CSD, etc) for the group is decided by the maximum values configured for the corresponding Y line.

Node Mapping Information

Screenshot of Touch.c showing Node Mapping

If the number of sensors is not a multiple of four or if each Y line does not have a multiple of four sensors, then the total number of nodes and buttons does not match. Even if everything is multiple of four, the buttons may not be sequentially assigned for a given Y line. So, to map the node to an individual button, an array is created in the touch.c file. The array touch_key_node_mapping_4p in the touch.c file displays the button’s position in the group created.

Data Streamer

The Datastreamer displays only the available buttons in the Sensors tab and not the X_NONEs.

Button data in the Data Streamer display

Additional Group Example

A different Pin arrangement in the Signal Matrix view of Pin Mapping Tab

If the sensors are interchanged as above, the following changes reflect in both touch.h and touch.c file.

Screenshot of Touch.c with new Node Mapping

Screenshot of Touch.h showing new group parameter settings