AP08113
Capacitive-Touch Color Wheel Implementation
Modifying Color Wheel Software Code
Application Note
12
V1.0, 2010-08
4
Modifying Color Wheel Software Code
The Color Wheel software example code can be accessed and modified by the user with DAvE-Bench - Infineon’s
free tool chain. The user can modify the user-defined parameters (as described in
Section 4.1
), the timing, code
flow, enabling/disabling modules, and interrupts handling for example, as required for a specific application. The
Color Wheel software example code can be downloaded together with this application note.
4.1
User-Defined Parameters
There are 6 parameters which the user can modify for the Touch-Wheel Library based on their application board
and usage. The respective values and description are listed in
Table 3
.
The threshold value can be reduced to increase sensitivity, and the filter gain value can be reduced to allow a
faster response time. The user can modify the user-defined parameters to match their application. The estimated
compensation values for Wheel1 and Wheel2 can be obtained by calling Touch-Wheel Library function as
described in
Section 3.2.2
.
4.2
DAvE-Bench Tool
The Infineon’s free tools DAvE and DAvE-Bench are used to generate and compile the code for Color Wheel
application. The user should follow the procedure shown below and in
Figure 5
, when using DAvE-Bench to
modify and compile the code.
Procedure to modify Color Wheel Application software code:
•
Download and install DAvE-Bench (
www.infineon.com/dave-bench
)
•
Define a workspace for DAvE-Bench
•
Click “File” -> “Import” -> “XC800” -> “Existing Project”
•
Select the desired folder where the project exists (RGB_Wheel folder)
•
Default: Tick option - copy project into workspace (Future changes will be reflected at the project in the
workspace, while original copy remain unchanged)
•
Click “Finish” to import the project
•
Modify the software code
•
Click “Project” -> “Build Active Project” to compile the code
•
Check the status of compilation on “Console” box
•
If compilation is not successful, the bugs are listed in the “Problems” box
•
Once hex file is generated, download the hex file using DAvE-Bench (XC800_FLOAD), described further in
Chapter 5
.
Table 3
User-Defined Parameters for Color Wheel Software Code
Parameter
Current Value Description
COMPENSATION_WHEEL2
-11
Compensation value for Wheel2 due to environment
COMPENSATION_WHEEL1
-11
Compensation value for Wheel1 due to environment
AMPLITUDE_THRESHOLD
0x400
Threshold value for amplitude. Above threshold value is
considered as touch on the touch-wheel
AMPLITUDE_FILTER_GAIN
5
Filter gain value for amplitude
AMPLITUDE_START_VALUE
0x240
Start value for amplitude during initialization/start-up
TSVAL_SUBTRACTION
3
To wake up the device via centre button
Subtraction value to determine the threshold level.
Current TSVAL > (Saved TSVAL - SUBTRACTION)
means the centre button is detected as “no touch” - device
remains in Power Down Mode
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