PSoC™ 4: CY8CPROTO-040T demo

This code example demonstrates an implementation of a low-power application including recommended power states and transitions, tuning parameter adjustments, and the method of tuning. This example uses a self-capacitance-based button, a mutual-capacitance-based button, and a self-capacitance-based slider in multi sense CAPSENSE™ low-power (MSCLP - 5th-generation low-power CAPSENSE™) to demonstrate different considerations to implement a low-power design.

View this README on GitHub.

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Requirements

• ModusToolbox™ v3.2 or later

Note: This code example version requires ModusToolbox™ v3.2 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 VDD 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 both as a GUI tool and a command line tool.

Use Project Creator GUI

1. 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).

2. 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.

3. 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 "mtb-example-cy8cproto-040t-demo" application with the desired name "CY8CPROTO_040T_demo" 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-cy8cproto-040t-demo --user-app-name CY8CPROTO_040T_demo --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

1. Connect the USB cable between the CY8CPROTO-040T Kit and the PC, as shown in Figure 1.

   Figure 1. Connecting the CY8CPROTO-040T Kit with the PC

   

2. 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
   

3. After programming, the application starts automatically.

Note: After programming, you will see the following error message if the Debug mode is disabled. This can be ignored, or enabling debug will solve this error.

"Error: Error connecting Dp: Cannot read IDR"

4. Touch any of the sensors with your finger; LEDs turn ON, indicating the activation of different CAPSENSE™ sensors.

   Table 1. LED states for different sensors

   Sensor touched	LED indication
   CSD button	LED 2 turns ON
   CSX button	LED 2 turns ON
   CSD slider	LED 3 brightness changes based on touch position

   
   

   Both LEDs will be OFF when none of the sensors are touched.

5. Verify that the application is transitioning to different power modes based on the user input conditions as follows:

   If there is no user activity for a certain time (ACTIVE_MODE_TIMEOUT_SEC = 10 s), the application transitions to Active-low Refresh rate (ALR) mode. Here, the refresh rate is reduced to 32 Hz.

   Further non-activity for a certain time (ALR_MODE_TIMEOUT_SEC = 5 s) transitions the application to the lowest-power mode, called the Wake-on-Touch (WoT) mode, which scans the low-power widget at a low refresh rate (16 Hz).

   Figure 2. Low-power mode state machine

   

Monitor data using CAPSENSE™ Tuner

1. Open the CAPSENSE™ Tuner from the Tools section in the IDE Quick Panel.

   You can also run the CAPSENSE™ tuner application standalone from {ModusToolbox™ install directory}/ModusToolbox/tools_{version}/capsense-configurator/capsense-tuner. In this case, after opening the application, select File > Open and then 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 status LED is ON and not blinking; this indicates that the onboard KitProg3 is in CMSIS-DAP Bulk mode. See the 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 as shown in Figure 3.

   Figure 3. Tuner communication setup

   

   Select I2C under KitProg3 and configure it as follows:

   • I2C address: 8
   • Sub-address: 2 bytes
   • Speed (kHz): 400

   These are the same values set in the EZI2C resource as shown in Figure 4.

   Figure 4. Tuner Communication Setup parameters

   

4. Click Connect or select Communication > Connect to establish a connection.

   Figure 5. Establish connection

   

5. Click Start or select Communication > Start to begin data streaming from the device.

   Figure 6. Start Tuner communication

   

   The Widget/Sensor Parameters tab is updated with the parameters configured in the CAPSENSE™ Configurator window. The tuner displays the data from the sensor in the Widget View and Graph View tabs.

6. Set the Read mode to Synchronized mode. Navigate to the Widget view tab and notice that the touched widget is highlighted in blue as shown in Figure 7.

   Figure 7. Widget view of the CAPSENSE™ Tuner

   

7. Go to the Graph View tab to view the raw count, baseline, difference count, and status of each sensor. To view the sensor data for the buttons, select Button_Sns0 or Button1_Rx0 under Button0 and Button1, respectively (see Figure 8 and Figure 9). To view the slider sensor data, select LinearSlider0_Sns0 under LinearSlider0 (see Figure 10).

   Figure 8. Graph view of the CAPSENSE™ Tuner for the CSD button

   

   Figure 9. Graph view of the CAPSENSE™ Tuner for the CSX button

   

   Figure 10. Graph view of the CAPSENSE™ Tuner for the CSD slider

   

8. Observe that the low-power widget sensor (LowPower0_Sns0) raw count is plotted after the device completes the full frame scan (or detects a touch) in WoT mode and moves to Active/ALR mode.

   Figure 11. Graph view of the CAPSENSE™ Tuner for the low-power widget

   

9. The tuning procedure, using the CAPSENSE™ Tuner for specific widgets is explained in the corresponding code examples mentioned in the Tuning parameters section.

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. See the Kit user guide to set the preferred operating voltage and refer to the section Setup the VDDA supply voltage and Debug mode.

The functionalities of this application is optimally tuned for 5 V. Observe that the basic functionalities work across other voltages.

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

Measure current at different power modes

1. 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)
   

2. Disable the self-test library from the CAPSENSE™ configurator as shown in Figure 12.

   Figure 12. Disable self-test library

   

3. Disable the Debug mode (if enabled). By default, it is disabled. See Setup the VDDA supply voltage and debug mode to enable. Enabling Debug mode keeps the SWD pins active in all device power modes and even during Deep Sleep. This leads to increase in power consumption.

4. 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 Figure 13.

   Figure 13. Power analyzer connection

   

5. Use "Keysight BenchVue Advanced Power Control and Analysis" software to control the power analyzer device through the PC.

6. Select the Current Measure option from the Instrument Control setup. Select and turn ON the output channel, as shown in Figure 14.

   Figure 14. Current measurement setup

   

7. 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 Figure 15.

   Figure 15. Current measurement

   

8. After reset, the application transitions to a low-power state if there is no button touch detection, in order to reduce power consumption, as shown in Figure 16.

   Figure 16. Power mode transition - no user activity

   

9. If there is touch detection while in low-power state, the application transitions to Active mode with the highest refresh rate as shown in Table 2.

   Table 2. Measured current for different modes

   Power mode	Refresh rate (Hz)	Current consumption (µA)
   Active	128	148
   Active-low refresh rate (ALR)	32	39
   Wake-on-Touch (WoT)	16	3.9

   
   

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 ~4.7 µA.

Tuning procedure

Create custom BSP for your board

1. Follow the steps shown in ModusToolbox™ BSP Assistant user guide to create a custom BSP for your board having any device. In this code example, it is created for the CY8C4046LQI-T452 device.

2. Open the design.modus file from {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 follows.

Note: See the section "Selecting CAPSENSE™ hardware parameters" in AN85951 – PSoC™ 4 design guide to learn about the considerations for selecting each parameter value. In addition, see the section "Low-power Widget parameters" in AN234231 – Achieving lowest power capacitive sensing with PSoC™ 4000T for more details about the considerations for parameter values specific to low-power widgets.

Figure 17. Low-power widget tuning flow

Tuning parameters

This code example has the optimum tuning parameters for all the sensors. See the following code examples that describe the tuning procedure for different sensors:

1. CE238886 for tuning the low-power widget and self-capacitance button

2. CE238820 for mutual-capacitance button tuning procedure

3. CE238818 for self-capacitance slider tuning procedure

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 more 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 design has a ratiometric implementation of the following sensors:

1. One Wake-on-Touch widget (2 elements), also called "Low-power Widget"
2. One self-capacitance button widget (1 element)
3. One mutual-capacitance button widget (2 elements)
4. One slider widget (5 elements)

Following are the two LEDs used in this project:

• LED 2 shows the button touch status: It turns ON when touched and turns OFF when the finger is lifted.
• LED 3 shows the slider touch status: It's brightness changes based on the finger touch position.

There are three power states defined for this project:

• Active mode

• Active-low refresh rate (ALR) mode

• Wake-on-Touch (WoT) mode

After reset, the device is in Active mode, and scans the regular CAPSENSE™ widgets with a high refresh rate (128 Hz). If user activity is detected in any other mode, the device is transferred to Active mode to provide the best user interface experience. This mode has the highest power consumption; therefore, the design should reduce the time spent in Active mode.

If there is no user activity for a certain period of time (ACTIVE_MODE_TIMEOUT_SEC = 10 s), the application transitions to ALR mode. Here, the refresh rate is reduced to 32 Hz; and hence this mode acts as an intermediate state before moving to the lowest-power mode (WoT mode). This mode can also be used for periodically updating the baselines of sensors while there is no user activity for a long time.

Further non-activity for a certain time span (ALR_MODE_TIMEOUT_SEC = 5 s) transitions the application to the lowest-power mode, called the Wake-on-Touch mode, which scans the low-power widget at a low refresh rate (16 Hz) and processes the results without CPU intervention.

Note: An internal low-power timer (MSCLP timer) is available in CAPSENSE™ MSCLP hardware to set the refresh rate for each power mode as follows:

• For Active and ALR modes: Use the Cy_CapSense_ConfigureMsclpTimer() function
• For WoT mode: Use the Wake-on-Touch scan interval in CAPSENSE™ configurator

Different power modes and transition conditions for a typical use case are shown in Figure 18.

Figure 18. State machine showing different power states of the device

The project uses the CAPSENSE™ middleware (see ModusToolbox™ user guide for more details on selecting a middleware). See AN85951 – PSoC™ 4 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 using the CAPSENSE™ Tuner. See EZI2C Peripheral settings.

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™.

Set up the VDDA supply voltage and Debug mode in Device Configurator

1. Open Device Configurator from the Quick Panel.

2. Go to the System tab, select the Power resource, and set the VDDA value under Operating conditions as shown in Figure 19.

   Figure 19. Setting the VDDA supply in System tab of Device Configurator

   

3. By default, the Debug mode is disabled for this application to reduce power consumption. Enable the Debug mode to enable SWD pins as shown in Figure 20.

   Figure 20. Enable the Debug mode in the System tab of Device Configurator

   

Resources and settings

Figure 21. EZI2C settings

Figure 22. PWM settings

Table 7. Application resources

Resource	Alias/object	Purpose
SCB (I2C) (PDL)	CYBSP_EZI2C	EZI2C slave driver to communicate with CAPSENSE™ Tuner
SCB (SPI) (PDL)	CYBSP_MASTER_SPI	SPI master driver to control serial LEDs
CAPSENSE™	CYBSP_MSC	CAPSENSE™ driver to interact with the MSC hardware and interface the CAPSENSE™ sensors
Digital pin	CYBSP_PWM	To show the slider operation

Firmware flow

Figure 23. Firmware flowchart

Related resources

Resources	Links
Application notes	AN79953 – Getting started with PSoC™ 4 AN234231 – PSoC™ 4 – Achieving lowest-power capacitive sensing with PSoC™ 4000T AN85951 – PSoC™ 4 design guide
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-pdl-cat2 – PSoC™ 4 Peripheral Driver Library (PDL) mtb-hal-cat2 – Hardware Abstraction Layer (HAL) library
Middleware on GitHub	capsense – CAPSENSE™ library and documents
Tools	ModusToolbox™ – ModusToolbox™ software 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: CE238817 – PSoC™ 4: CY8CPROTO-040T demo

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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