Generate Mutual Cap Parallel Acquisition Project

1

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.)

MutualcapButton.png

2

Sensor Layout View

SensorLayout.png

3

Enabling Parallel Acquisition

After configuring the sensors and pins, to enable the parallel acquisition, select the ‘Enable Parallel Acquisition for Improved SNR’ checkbox.

ParallelAcquisition.png

4

Pin Selection View

PinSelection.png

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.

TouchHeaderFile.png

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

5

Node Mapping Information

NodeMapping.png

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.

6

Data Streamer

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

DataStreamer.png

Additional Group Example

GroupExample.png

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

TouchC.png
TouchH.png
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