Objective
In the projects leading up to this one, we've been using the 'V' in the AVR® symbol as our touch button. To demonstrate the Adjacent Key Suppression™ feature, we need more than one touch sensor. In this project, we will configure two additional touch buttons (the 'A' and the 'R' in the AVR logo on the ATmega328PB Xplained Mini) and observe the touch status when AKS is disabled. We will then add all three sensors to a single AKS group and observe the results.
This tutorial builds on the Intro to PTC and Analyze Touch Data Using QTouch® Analyzer projects. Make sure you've completed those before continuing with this hands-on exercise.
Materials
Hardware Tools
| Tool | About | Purchase |
|---|---|---|
 ATmega328PB Xplained Mini
Evaluation Kit |
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Software Tools
| Tool | About | Installers |
Installation
Instructions |
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|---|---|---|---|---|---|
| Windows | Linux | Mac OSX | |||
 Atmel® Studio
Integrated Development Environment |
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Procedure
1
Stop Reading
If you've just completed the Changing the Detect Hysteresis project, you should click on Stop Reading.
2
Open the QTouch Project Builder
In the Solution Explorer window, double-click on the .qtdgn file. Note that you may have named your project differently.
3
Add Button
Click on the Button icon
In the Add Sensors dialogue box, set the 'Number of Button' to 2 and click Add.
You'll see that two more buttons are added to the QTouch kit canvas.
4
Assign Pins
In the Project Builder Workflow window, click on the 'Pin Selection' tab.
| A | PE2 | Y6 |
| V | PE3 | Y7 |
| R | PC3 | Y3 |
Ensure that the order of pin assignments is similar to the one below. This would ensure that sensor numbering of your project is similar to the one followed in this tutorial.
5
Generate Project
Go to the 'Project Generation' section and click Generate Project.
6
Build and Program
Build the solution.
Program the application by clicking on the 'Start Without Debugging' icon.
7
QTouch Analyzer
Open the QTouch Analyzer window by clicking on the icon as shown below.
In the QTouch Analyzer window, click ReConnect.
Click on Start Reading.
Use the 'Tabular View' to observe touch delta and state.
8
Touch Two Buttons
Touch the sensors so that contact is made with more than one sensor simultaneously as shown below.
9
Detect State
Multiple sensors are reported to be in detect state.
AKS Grouping
For the next part of this lab, we are now going to add all three sensors to a single AKS group and observe the difference in touch status.
10
Stop Reading
In the QTouch Analyzer window, click on Stop Reading.
11
Open the QTouch Project Builder
In the Solution Explorer window, double click on the .qtdgn file.
12
Change Button Settings
Select 'Button0' on the QTouch kit canvas and click on the setting icon.
Set the 'AKS Group' setting to AKS_Group_1.
13
Set AKS Group for Button1 and Button2
Similarly, set the 'AKS Group' as AKS_Group_1 for the rest of the buttons (Button1 and Button2).
14
Generate Project
Go to the 'Project Generation' section and click Generate Project.
15
Build and Program
Build the solution.
Program the application by clicking on the 'Start Without Debugging' icon.
16
QTouch Analyzer
Open QTouch Analyzer.
In the QTouch Analyzer window, click ReConnect.
Click on Start Reading.
Use the 'Tabular View' to observe touch delta and state.
17
Touch Two Buttons
Touch the sensors so that contact is made with more than one sensor simultaneously as shown below.
18
Touch Detect
Although multiple sensors may have a delta greater than their respective detect threshold, only one sensor will report touch detection.
When a group of sensors is in the same AKS group, only the sensor with the strongest delta will report detection. Using this parameter is important in designs where the sensors are close together or configured for high sensitivity as it will avoid multiple sensors to report a touch detection simultaneously.
Results
You have now learned how to configure the AKS parameter in a QTouch Project.