PSoC™ 4: MSCLP low-power self-capacitance slider

This code example demonstrates how to use the CAPSENSE™ middleware to detect a finger touch position on a self-capacitance-based slider widget in PSoC™ 4000T device with multi-sense converter low-power (MSCLP) CAPSENSE™ block.

In addition, this code example also explains how to manually tune the self-capacitance-based slider for optimum performance with respect to parameters such as reliability, power consumption, response time, and linearity using the CSD-RM sensing technique and CAPSENSE™ Tuner. Here, capacitive sigma-delta (CSD) represents the self-capacitance sensing technique and RM represents the ratiometric method.

View this README on GitHub.

Provide feedback on this code example.

Requirements

ModusToolbox™ v3.2 or later

Note: This code example version requires ModusToolbox™ version 3.2 or later, and is not backward compatible with v3.1 or older versions.
Board support package (BSP) minimum required version: 3.2.0
Programming language: C
Associated parts: PSoC™ 4000T

Supported toolchains (make variable 'TOOLCHAIN')

GNU Arm® Embedded Compiler v11.3.1 (GCC_ARM) – Default value of TOOLCHAIN
Arm® Compiler v6.16 (ARM)
IAR C/C++ Compiler v9.30.1 (IAR)

Supported kits (make variable 'TARGET')

PSoC™ 4000T CAPSENSE™ Prototyping Kit (CY8CPROTO-040T) - Default TARGET

Hardware setup

This example uses the board's default configuration. See the Kit user guide to ensure that the board is configured correctly to use VDDA at 5 V.

Software setup

See the ModusToolbox™ tools package installation guide for information about installing and configuring the tools package.

This example requires no additional software or tools.

Using the code example

Create the project

The ModusToolbox™ tools package provides the Project Creator as both a GUI tool and a command line tool.

Use Project Creator GUI

Open the Project Creator GUI tool.

There are several ways to do this, including launching it from the dashboard or from inside the Eclipse IDE. For more details, see the Project Creator user guide (locally available at {ModusToolbox™ install directory}/tools_{version}/project-creator/docs/project-creator.pdf).
On the Choose Board Support Package (BSP) page, select a kit supported by this code example. See Supported kits.

Note: To use this code example for a kit not listed here, you may need to update the source files. If the kit does not have the required resources, the application may not work.
On the Select Application page:

a. Select the Applications(s) Root Path and the Target IDE.

Note: Depending on how you open the Project Creator tool, these fields may be pre-selected for you.

b. Select this code example from the list by enabling its check box.

Note: You can narrow the list of displayed examples by typing in the filter box.

c. (Optional) Change the suggested New Application Name and New BSP Name.

d. Click Create to complete the application creation process.

Use Project Creator CLI

The 'project-creator-cli' tool can be used to create applications from a CLI terminal or from within batch files or shell scripts. This tool is available in the {ModusToolbox™ install directory}/tools_{version}/project-creator/ directory.

Use a CLI terminal to invoke the 'project-creator-cli' tool. On Windows, use the command-line 'modus-shell' program provided in the ModusToolbox™ installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ tools. You can access it by typing "modus-shell" in the search box in the Windows menu. In Linux and macOS, you can use any terminal application.

The following example clones the "MSCLP low power CSD slider" application with the desired name "MSCLP_Low_Power_CSD_Slider" configured for the CY8CPROTO-040T BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id CY8CPROTO-040T --app-id mtb-example-psoc4-msclp-low-power-csd-slider --user-app-name MSCLP_Low_Power_CSD_Slider --target-dir "C:/mtb_projects"

The 'project-creator-cli' tool has the following arguments:

Argument	Description	Required/optional
`--board-id`	Defined in the field of the BSP manifest	Required
`--app-id`	Defined in the field of the CE manifest	Required
`--target-dir`	Specify the directory in which the application is to be created if you prefer not to use the default current working directory	Optional
`--user-app-name`	Specify the name of the application if you prefer to have a name other than the example's default name	Optional

Note: The project-creator-cli tool uses the git clone and make getlibs commands to fetch the repository and import the required libraries. For details, see the "Project creator tools" section of the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Open the project

After the project has been created, you can open it in your preferred development environment.

Eclipse IDE

If you opened the Project Creator tool from the included Eclipse IDE, the project will open in Eclipse automatically.

For more details, see the Eclipse IDE for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_ide_user_guide.pdf).

Visual Studio (VS) Code

Launch VS Code manually, and then open the generated {project-name}.code-workspace file located in the project directory.

For more details, see the Visual Studio Code for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_vscode_user_guide.pdf).

Keil µVision

Double-click the generated {project-name}.cprj file to launch the Keil µVision IDE.

For more details, see the Keil µVision for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_uvision_user_guide.pdf).

IAR Embedded Workbench

Open IAR Embedded Workbench manually, and create a new project. Then select the generated {project-name}.ipcf file located in the project directory.

For more details, see the IAR Embedded Workbench for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_iar_user_guide.pdf).

Command line

If you prefer to use the CLI, open the appropriate terminal, and navigate to the project directory. On Windows, use the command-line 'modus-shell' program; on Linux and macOS, you can use any terminal application. From there, you can run various make commands.

For more details, see the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Operation

Connect the board to your PC using the provided USB cable through the KitProg3 USB connector as follows:

Figure 1. Connecting the CY8CPROTO-040T kit with the PC
Program the board using one of the following:
Using Eclipse IDE
1. Select the application project in the Project Explorer.
2. In the Quick Panel, scroll down, and click <Application Name> Program (KitProg3_MiniProg4).
In other IDEs

Follow the instructions in your preferred IDE.
Using CLI

From the terminal, execute the make program command to build and program the application using the default toolchain to the default target. The default toolchain is specified in the application's Makefile but you can override this value manually:
```
make program TOOLCHAIN=<toolchain>
```
Example:
```
make program TOOLCHAIN=GCC_ARM
```
After programming, the application starts automatically.

Note: After programming, you see the following error message if debug mode is disabled. Ignore the error or enable the debug mode to solve this error.
```
"Error: Error connecting Dp: Cannot read IDR"
```
To test the application, slide your finger over the CAPSENSE™ slider and notice that the LED3 turn ON when touched and turn OFF when the finger is lifted. The LED3 brightness increases when the finger is swiped from left to right.
You can also monitor the CAPSENSE™ data using the CAPSENSE™ Tuner application as follows:

Monitor data using CAPSENSE™ Tuner
1. Open CAPSENSE™ Tuner from the tools section in the IDE Quick Panel.
  
  You can also run the CAPSENSE™ Tuner application in standalone mode from {ModusToolbox™ install directory}/ModusToolbox/tools_{version}/capsense-configurator/capsense-tuner. In this case, after opening the application, select File > Open and open the design.cycapsense file of the respective application, which is present in the {Application root directory}/bsps/TARGET_APP_<BSP-NAME>/config/ folder.
  
  See the ModusToolbox™ user guide {locally available at ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf for options to open the CAPSENSE™ Tuner application using the CLI.
2. Ensure that the kit is in CMSIS-DAP bulk mode (KitProg3 status LED is ON and not blinking). See Firmware-loader to learn how to update the firmware and switch modes in KitProg3.
3. In the tuner application, click on the Tuner Communication Setup icon or select Tools > Tuner Communication Setup. In the window, select the I2C checkbox under KitProg3 and configure as follows:
  - I2C address: 8
  - Sub-address: 2 Bytes
  - Speed (kHz): 400
    
    These are the same values set in the EZI2C resource.
Figure 2. Tuner communication setup parameters
Click Connect or select Communication > Connect to establish a connection.

Figure 3. Establish a connection
Click Start or select Communication > Start to start data streaming from the device.

Figure 4. Start tuner communication

The tuner displays the data from the sensor in the Widget View, Graph View, and Touchpad View tabs.
Set Read mode to Synchronized mode. Under the Widget View tab, you can see the LinearSlider0 widget highlighted in Blue when you touch it, as shown in Figure 5.

Figure 5. Widget view of the CAPSENSE™ Tuner
You can view the raw count, baseline, difference count, status for each sensor, and slider position in the Graph View tab. For example, to view the sensor data for LinearSlider0, select LinearSlider0_Sns0 under LinearSlider0.

Figure 6. Graph View tab of the CAPSENSE™ Tuner
See the Widget/Sensor Parameters section in the CAPSENSE™ Tuner window. The configuration parameters for each slider sensor element calculated by the CAPSENSE™ resource are displayed, as shown in Figure 6.
Verify that the SNR is greater than 5:1 and the signal count is above 50 by following the steps given in Stage 3: Obtain noise and crossover point.

Non-reporting of false touches and the linearity of the position graph indicate proper tuning.

Note: Refer to the PSoC™ 4: MSCLP low-power CSD button to observe the power state transitions, indicated by changing the blinking rate of a LED. The Code Example also explains the scan time and process time measurements.

Operation at other voltages

CY8CPROTO-040T kit supports operating voltages of 1.8 V, 3.3 V, and 5 V. Refer to the Kit user guide to set the preferred operating voltage and refer to section setup the VDDA supply voltage and Debug mode.

This application functionalities are optimally tuned for 5 V. However, basic functionalities works on other voltages.

For better performance, it is recommended to tune the application for the preferred voltages.

Tuning procedure

Create a custom BSP for your board

Create a custom BSP for your board having any device, by following the steps given in ModusToolbox™ BSP Assistant user guide. This code example was created for the device "CY8C4046LQI-T452".
Open the design.modus file from the {Application root directory}/bsps/TARGET_APP_<BSP-NAME>/config/ folder obtained in the previous step and enable CAPSENSE™ to get the design.cycapsense file. CAPSENSE™ configuration can then be started from scratch as explained below.

The following steps explain the tuning procedure.

Note: See the section "Selecting CAPSENSE™ hardware parameters" in the PSoC™ 4 and PSoC™ 6 MCU CAPSENSE™ design guide to learn about the considerations for selecting each parameter value.

Figure 7. CSD slider widget tuning flow

Do the following to tune the slider widget:

Stage 1: Set the initial hardware parameters
Stage 2: Set the Sense clock frequency
Stage 3: Obtain noise and crossover point
Stage 4: Fine-tune sensitivity to improve SNR
Stage 5: Tune threshold parameters

Stage 1: Set the initial hardware parameters

Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.
Launch the Device Configurator tool.

You can launch the Device Configurator in Eclipse IDE for ModusToolbox™ from the Tools section in the IDE Quick Panel or in standalone mode from {ModusToolbox™ install directory}/ModusToolbox/tools_{version}/device-configurator/device-configurator. In this case, after opening the application, select File > Open and open the design.modus file of the respective application, located in the {Application root directory}/bsps/TARGET_APP_<BSP-NAME>/config/ folder.
In the PSoC™ 4000T Prototyping Kit, the slider pins are connected to CAPSENSE™ channel (MSCLP 0). Therefore, make sure that you enable CAPSENSE™ channel in the Device Configurator, as shown in Figure 8.

Figure 8. Enable MSCLP channel in the Device Configurator

Save the changes and close the window.
Launch the CAPSENSE™ Configurator tool.

You can launch the CAPSENSE™ Configurator tool in the Eclipse IDE for ModusToolbox™ from the CAPSENSE™ peripheral setting in the Device Configurator or directly from the Tools section in the IDE Quick Panel. You can also launch it in standalone mode from {ModusToolbox™ install directory}/ModusToolbox/tools_{version}/capsense-configurator/capsense-configurator. In this case, after opening the application, select File > Open and open the design.cycapsense file of the respective application, located in the {Application root directory}/bsps/TARGET_APP_<BSP-NAME>/config/ folder.

See the ModusToolbox™ CAPSENSE™ Configurator tool guide for step-by-step instructions on how to configure and launch CAPSENSE™ in ModusToolbox™.
In the Basic tab, note that the slider 'LinearSlider0' is configured with CSD RM (self-cap) Sensing mode. A low power widget 'LowPower0' is also configured to scan in the Wake-on-Touch (WOT) mode.

Figure 9. CAPSENSE™ Configurator - Basic tab
Go to Advanced > General tab and do the following:
1. Select CAPSENSE™ IMO clock frequency as 46 MHz.
2. Set Modulator clock divider to '1' to obtain the maximum available modulator clock frequency as recommended in the PSoC™ 4 and PSoC™ 6 MCU CAPSENSE™ design guide.
  
  Note: The modulator clock frequency can be set to 46,000 kHz after changing the CAPSENSE™ IMO clock frequency to 46 MHz, because the modulator clock is derived from the CAPSENSE™ IMO clock. In the CAPSENSE™ IMO clock frequency drop-down list, select 46 MHz.
3. Number of init sub-conversions is set based on the hint shown when you hover over the edit box. Retain the default value.
4. It is recommended to Enable IIR filter (first order) and set the IIR filter raw count coefficient to '128' when the CIC2 filter is enabled. You can enable the filters later depending on the signal-to-noise ratio (SNR) requirements in Stage 4: Fine-tune sensitivity to improve SNR.
  
  Note: Filters are used to reduce the peak-to-peak noise. Using filters will result in a longer scan time.
  
  Figure 10. CAPSENSE™ Configurator – General settings
  
  Note: Each tab has a Restore Defaults button to restore the parameters of that tab to their default values.
Go to the CSD Settings tab and make the following changes:
- Set Inactive sensor connection as Shield
  
  Inactive sensors connected to Shield provide better performance in terms of SNR and refresh rate (as the use of shield results in a reduction of sensor Cp) and can also be used if your design requires liquid tolerance.
- Set Shield mode to Active
  
  MSCLP provides active and passive shielding. Active shielding is preferred for high-performance applications. Before enabling this option, ensure that the design has shield electrodes.
- Set Total shield count as 5
  
  This is equal to the number of shield electrodes in your design. It is zero when only the inactive sensors are shielded.
- Select Enable CDAC auto-calibration and Enable compensation CDAC
  
  This helps in achieving the required CDAC calibration levels for all sensors in the widget while maintaining the same sensitivity across the sensor elements. Set this to 70% for this application not to reach the saturation level on a touch event.
- Select Enable CDAC dither
  
  This helps in removing flat-spots by adding white noise that moves the conversion point around the flat-spot region.
Figure 11. CAPSENSE™ Configurator – Advanced CSD settings
Go to the Widget Details tab. Select LinearSlider0 from the left pane, and then set the following:
1. Maximum postion : Set to 100.
2. Sense clock divider: Retain the default value (will be set in Stage 2: Set the sense clock frequency).
3. Clock source: Direct
  
  Note: Spread Spectrum Clock (SSC) or PRS clock can be used as a clock source to deal with EMI/EMC issues.
4. Number of sub-conversions: 12
  
  12 is an appropriate starting point to ensure a fast scan time and sufficient signal. This value will be adjusted as required in Stage 4: Fine-tune sensitivity to improve SNR.
5. Finger threshold: 20
  
  Finger threshold is initially set to a low value, allowing to track the finger movement during tuning.
6. Noise threshold: 10
7. Negative noise threshold: 10
8. Hysteresis: 5
These values reduce the influence of the baseline on the sensor signal, which helps to get the true difference count. Retain the default values for all other threshold parameters; these parameters are set in Stage 5: Tune threshold parameters.

Figure 12. CAPSENSE™ Configurator – Widget Details settings
Go to the Scan Configuration tab to select the pins, the scan slots, and do the following:

Figure 13. Scan Configuration tab
1. Configure pins for the electrodes using the drop-down menu.
2. Configure the scan slots using the Auto-assign Slots option.
  
  The summary section in the Scan configuration tab shows five scan slots (for five sensors). Each sensor is allotted a scan slot based on the slot number.
3. Check the notice list for warnings or errors.
  
  Note: Enable the Notice List from the View menu if the notice list is not visible.
Click Save to apply the settings.

Stage 2: Set the sense clock frequency

The sense clock is derived from the modulator clock using a clock-divider and is used to scan the sensor by driving the CAPSENSE™ switched capacitor circuits. Both the clock source and clock divider are configurable. The sense clock divider should be configured such that the pulse width of the sense clock is long enough to allow the sensor capacitance to charge and discharge completely. This is verified by observing the charging and discharging waveforms of the sensor using an oscilloscope and an active probe. The sensors should be probed close to the electrode and not at the sense pins or the series resistor.

See Figure 14 and Figure 15 for waveforms observed on the shield. Figure 14 shows proper charging when the sense clock frequency is correctly tuned. The pulse width is at least 5 Tau, i.e., the voltage is reaching at least 99.3% of the required voltage at the end of each phase. Figure 15 shows incomplete settling (charging/discharging).

Figure 14. Proper charge cycle of a sensor

Figure 15. Improper charge cycle of a sensor

Program the board and launch CAPSENSE™ Tuner.
See the charging waveform of the sensor as described earlier.
If the charging is incomplete, increase the sense clock divider. This can be done in CAPSENSE™ Tuner by selecting the sensor and editing the sense clock divider parameter in the Widget/Sensor Parameters panel.

Note: The sense clock divider should be divisible by 4. This ensures that all four scan phases have equal durations.

After editing the value, click the Apply to Device button and observe the waveform again. Repeat this until complete settling is observed.
Click the Apply to Project button to save the configuration to your project.

Figure 16. Sense clock divider setting
Repeat this process for all the sensors and the Shield. Each sensor may require a different sense clock divider value to charge/discharge completely. But all the sensors that are in the same scan slot need to have the same sense clock source, sense clock divider, and number of sub-conversions. Therefore, take the largest sense clock divider in a given scan slot and apply it to all the other sensors that share that slot.

Stage 3: Obtain noise and crossover point

Program the board.
Launch the CAPSENSE™ Tuner to monitor the CAPSENSE™ data and for CAPSENSE™ parameter tuning and SNR measurement.

See the CAPSENSE™ Tuner guide for step-by-step instructions on how to launch and configure the CAPSENSE™ Tuner in ModusToolbox™.
Capture and note the peak-to-peak noise of each segment of the slider.
1. From the Widget Explorer section, select a sensor (for example, LinearSlider0_Sns0).
2. Go to the SNR Measurement tab and click Acquire Noise to capture peak-to-peak noise, as shown in Figure 17.
Figure 17. Noise obtained on the SNR Measurement tab in Tuner window
1. Repeat Steps 1 and 2 for all the sensors to capture peak-to-peak noise.
  
  Table 3. Peak-to-peak noise obtained for each segment
  
  Slider segment Peak-to-peak noise (CY8CPROTO-040T)
  
  SNS0 39
  
  SNS1 46
  
  SNS2 48
  
  SNS3 41
  
  SNS4 40

Use a grounded metal finger and swipe it slowly at a constant speed from the start to the end of the slider.
1. Go to the Graph View tab to view a graph similar to Figure 19.
2. Get the upper crossover point (UCP) and lower crossover point (LCP), as shown in Figure 19.
  
  Figure 18. Difference count (delta) vs. finger position
Sensor signal values at points a, b, c, and d are expected to be at approximately the same level. If the values are slightly different, consider the lowest value as the UCP.

Sensor signal values at points q, r, and s are expected to be at approximately the same level. If the values are slightly different, consider the lowest value as the LCP.
```
**Figure 19. Sensor signal (difference counts) displayed in the Graph View tab**
```
Note: In this example, for tuning, a 6 mm metal finger is used.

Stage 4: Fine-tune sensitivity to improve SNR

The CAPSENSE™ system may be required to work reliably in adverse conditions such as a noisy environment. Tune the slider segments with SNR greater than 5:1 to avoid triggering false touches and ensure that all intended touches are registered in these adverse conditions.

Ensure that all UCPs meet at least 5:1 SNR (using Equation 1) and all LCPs are greater than twice the peak-to-peak noise for all slider segments.

In the CAPSENSE™ Tuner window, increase the Number of sub-conversions (located in Widget Hardware Parameters > Widget/Sensor Parameters section) by 10 until you achieve at least 5:1 SNR.

Equation 1. SNR equation
Update the number of sub-conversions.
1. Update the number of sub-conversions (Nsub) directly in the Widget/Sensor parameters tab of the CAPSENSE™ Tuner.
2. CY8CPROTO-040T has an in-built CIC2 filter which increases the resolution for the same scan time. See AN234231 - Achieving lowest-power capacitive sensing with PSoC™ 4000T for detailed information on the CIC2 filter.
3. Current consumption is directly proportional to the number of sub-conversions; therefore, decrease the number of sub-conversions to achieve lower current consumption.
After changing the Number of sub-conversions, click Apply to Device to send the setting to the device. The change is reflected in the graphs.

Note: The Apply to Device option is enabled only when the Number of sub-conversions is changed.

Note: Decrease the IIR filter coefficient if 5:1 SNR is not being achieved even with maximum Nsub.

Stage 5: Tune threshold parameters

After confirming that your design meets the timing parameters and the SNR is greater than 5:1, set the threshold parameters as follows:

Set the recommended threshold values for the Slider widget using the LCP and UCP obtained in Stage 4: Fine-tune sensitivity to improve SNR:

Finger Threshold = 80% of UCP
Noise Threshold = Minimum (twice the peak-to-peak noise, LCP)
Negative Noise Threshold = Minimum (twice the peak-to-peak noise, LCP)
Low Baseline Reset = Default value of '30'
Hysteresis = 10% of UCP
ON Debounce = Default value of '3'

Table 4. Software tuning parameters

Parameter	CY8CPROTO-040T
Number of sub-conversions	16
Finger threshold	528
Noise threshold	48
Negative noise threshold	48
Low baseline reset	30
Hysteresis	66
ON debounce	3

Tuning parameters

This code example has the tuning flow explained for the CSD slider widget. See CE238886 PSoC™ 4: MSCLP Low Power CSD Button for tuning the low-power widget.

Apply the settings to the firmware

Click Apply to Device and Apply to Project in the CAPSENSE™ Tuner window to apply the settings to the device and project, respectively. Close the tuner.

Figure 20. Apply to project

The change is updated in the design.cycapsense file and reflected in the CAPSENSE™ Configurator.

Measure current at different power modes

Disable the run-time measurement, serial LED, and tuner macros to measure the current used for CAPSENSE™ sensing in each power mode in main.c, and disable the self-test library from the CAPSENSE™ Configurator as follows:
```
   #define ENABLE_RUN_TIME_MEASUREMENT      (0u)
   
   #define ENABLE_PWM_LED                   (0u)

   #define ENABLE_TUNER                     (0u)
```
Figure 25. Disable self-test library
To evaluate the low-power feature of the device, connect the kit to a Power Analyzer (for example, KEYSIGHT - N6705C) using a current measure header, as shown in the following figure:

Figure 22. Power analyzer connection
Use "Keysight BenchVue Advanced Power Control and Analysis" software to control the power analyzer device through the PC.
Select the Current Measure option from the Instrument Control setup. Then, select and turn ON the output channel, as shown in the following figure:

Figure 23. Current measurement setup
Capture the data using the Data logger option from the tool. The average current consumption is measured using cursors on each power mode, as shown in the following figure.

Figure 24. Current measurement
After reset, the application transitions to low-power state if there is no user activity (for example, button touch detection) to reduce the power consumption, as shown in the following figure.

Figure 25. Power mode transition – no user activity
If there is a touch detection while in low-power state, the application transitions to Active mode with the highest refresh rate as follows:

Table 5. Measured current for different modes

Power mode Refresh rate (Hz) Current consumption (µA)

Active 128 122

Active low-refresh rate
(ALR) 32 32

Wake-on-touch
(WoT) 16 3.8

Note: The earlier WoT current was measured on a kit with 1.7 µA Deep Sleep current. If the kit has a Deep Sleep current of 2.5 µA (typical), the WoT current is expected to be ~4.6 µA.

Debugging

You can debug the example to step through the code.

In Eclipse IDE

Use the <Application Name> Debug (KitProg3_MiniProg4) configuration in the Quick Panel. For details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ user guide.

In other IDEs

Follow the instructions in your preferred IDE.

Design and implementation

The project contains a slider widget configured in CSD-RM sensing mode. See the Tuning procedure section for step-by-step instructions to configure the other settings of the CAPSENSE™ Configurator.

The project uses the CAPSENSE™ middleware (see ModusToolbox™ user guide for more details on selecting a middleware). See AN85951 – PSoC™ 4 and PSoC™ 6 MCU CAPSENSE™ design guide for more details on CAPSENSE™ features and usage.

The ModusToolbox™ provides a GUI-based tuner application for debugging and tuning the CAPSENSE™ system. The CAPSENSE™ Tuner application works with EZI2C and UART communication interfaces. This project has an SCB block configured in EZI2C mode to establish communication with the onboard KitProg, which in turn enables reading the CAPSENSE™ raw data by the CAPSENSE™ Tuner.

The CAPSENSE™ data structure that contains the CAPSENSE™ raw data is exposed to the CAPSENSE™ Tuner by setting up the I2C communication data buffer with the CAPSENSE™ data structure. This enables the tuner to access the CAPSENSE™ raw data for tuning and debugging CAPSENSE™.

The successful tuning of the slider is indicated by the LED3 in the Prototyping Kit; the LED3 brightness increases when the finger is swiped from left to right.

The PWM pin is used for controlling brightness, and ON or OFF operation of the LED3.

Steps to set up the VDDA supply voltage in Device Configurator

Open Device Configurator from the Quick Panel.
Go to the System tab. Select the Power resource and set the VDDA value under Operating Conditions, as shown in Figure 26.

Figure 26. Setting the VDDA supply in the system tab of Device Configurator
By default, Debug mode is disabled for this application to reduce power consumption. Enable Debug mode to enable SWD pins as follows:

Figure 27. Enable Debug mode in the System tab of Device Configurator

Resources and settings

Figure 28. EZI2C settings

Figure 29. PWM settings

Table 6. Application resources

Resource	Alias/object	Purpose
SCB (EZI2C) (PDL)	CYBSP_EZI2C	EZI2C slave driver to communicate with CAPSENSE™ Tuner
CAPSENSE™	CYBSP_MSC	CAPSENSE™ driver to interact with the MSCLP hardware and interface the CAPSENSE™ sensors
Digital pin	CYBSP_PWM	To show the slider operation

Firmware flow

Figure 30. Firmware flowchart

Related resources

Resources	Links
Application notes	AN79953 – Getting started with PSoC™ 4 AN85951 – PSoC™ 4 and PSoC™ 6 MCU CAPSENSE™ design guide AN234231 - Achieving lowest-power capacitive sensing with PSoC™ 4000T
Code examples	Using ModusToolbox™ on GitHub
Device documentation	PSoC™ 4 datasheets PSoC™ 4 technical reference manuals
Development kits	Select your kits from the Evaluation board finder.
Libraries on GitHub	mtb-hal-cat2 – Hardware Abstraction Layer (HAL) library
Middleware on GitHub	CAPSENSE™ Middleware Library – CAPSENSE™ library and documents
Tools	ModusToolbox™ – ModusToolbox™ is a collection of easy-to-use libraries and tools enabling rapid development with Infineon MCUs for applications ranging from wireless and cloud-connected systems, edge AI/ML, embedded sense and control, to wired USB connectivity using PSoC™ Industrial/IoT MCUs, AIROC™ Wi-Fi and Bluetooth® connectivity devices, XMC™ Industrial MCUs, and EZ-USB™/EZ-PD™ wired connectivity controllers. ModusToolbox™ incorporates a comprehensive set of BSPs, HAL, libraries, configuration tools, and provides support for industry-standard IDEs to fast-track your embedded application development.

Other resources

Infineon provides a wealth of data at www.infineon.com to help you select the right device, and quickly and effectively integrate it into your design.

Document history

Document title: CE238818 - PSoC™ 4: MSCLP low power self-capacitance slider

Version	Description of change
1.0.0	New code example.
2.0.0	Major update to support ModusToolbox™ v3.2 and CAPSENSE™ Middleware v5.0. This version is not backward compatible with previous versions of ModusToolbox™

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Name		Name	Last commit message	Last commit date
Latest commit History 2 Commits
deps		deps
images		images
templates/TARGET_CY8CPROTO-040T/config		templates/TARGET_CY8CPROTO-040T/config
.cyignore		.cyignore
.gitignore		.gitignore
LICENSE		LICENSE
Makefile		Makefile
README.md		README.md
main.c		main.c

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PSoC™ 4: MSCLP low-power self-capacitance slider

Requirements

Supported toolchains (make variable 'TOOLCHAIN')

Supported kits (make variable 'TARGET')

Hardware setup

Software setup

Using the code example

Create the project

Open the project

Operation

Operation at other voltages

Tuning procedure

Stage 1: Set the initial hardware parameters

Stage 2: Set the sense clock frequency

Stage 3: Obtain noise and crossover point

Stage 4: Fine-tune sensitivity to improve SNR

Stage 5: Tune threshold parameters

Tuning parameters

Apply the settings to the firmware

Measure current at different power modes

Debugging

Design and implementation

Steps to set up the VDDA supply voltage in Device Configurator

Resources and settings

Firmware flow

Related resources

Other resources

Document history

About

Releases

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Languages

Power mode	Refresh rate (Hz)	Current consumption (µA)
Active	128	122
Active low-refresh rate (ALR)	32	32
Wake-on-touch (WoT)	16	3.8

Slider segment	Peak-to-peak noise (CY8CPROTO-040T)
SNS0	39
SNS1	46
SNS2	48
SNS3	41
SNS4	40

License

Infineon/mtb-example-psoc4-msclp-low-power-csd-slider

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PSoC™ 4: MSCLP low-power self-capacitance slider

Requirements

Supported toolchains (make variable 'TOOLCHAIN')

Supported kits (make variable 'TARGET')

Hardware setup

Software setup

Using the code example

Create the project

Open the project

Operation

Operation at other voltages

Tuning procedure

Stage 1: Set the initial hardware parameters

Stage 2: Set the sense clock frequency

Stage 3: Obtain noise and crossover point

Stage 4: Fine-tune sensitivity to improve SNR

Stage 5: Tune threshold parameters

Tuning parameters

Apply the settings to the firmware

Measure current at different power modes

Debugging

Design and implementation

Steps to set up the VDDA supply voltage in Device Configurator

Resources and settings

Firmware flow

Related resources

Other resources

Document history

About

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