GitHub hosted

This example demonstrates implementing CapSense buttons and slider for PSoC 6 MCU with Mbed OS.

Download repository: zip

PSoC 6 MCU: CapSense Buttons and Slider

This code example demonstrates implementing CapSense® buttons and slider for PSoC® 6 MCU with Mbed OS using the CapSense Middleware Library. This example features a 5-segment CapSense slider and two CapSense buttons.

Tested with Mbed OS v6.2.1


Note: You do not need to install ModusToolbox to build and run this code example. However, installing it is required when you need to do the following:

  • Debug using the Eclipse IDE for ModusToolbox. See the user guide for details.
  • Customize the default device configuration using any of the Configurator tools
  • Port this code example to a new target that is not listed under the Supported Kits

Supported Toolchains (Mbed CLI argument --toolchain)

Supported Kits (Mbed CLI argument --target)

Hardware Setup

This example uses the board’s default configuration. See the kit user guide to ensure that the board is configured correctly.

Because this example is designed to work at the default operating voltage of the kit, ensure that the power setting jumper when present is configured at the default position. For the kits that support multiple operating voltages, see Operation at Custom Power Supply Voltage to run this example at a non-default voltage.

Note: The PSoC 6 BLE Pioneer Kit (CY8CKIT-062-BLE) and the PSoC 6 WiFi-BT Pioneer Kit (CY8CKIT-062-WIFI-BT) ship with KitProg2 installed. The ModusToolbox software requires KitProg3. Before using this code example, make sure that the board is upgraded to KitProg3. The tool and instructions are available in the Firmware Loader GitHub repository. If you do not upgrade, you will see an error like “unable to find CMSIS-DAP device” or “KitProg firmware is out of date”.

For Mbed OS, the kit must be in DAPLink mode. Refer the KitProg3 User Guide (Documentation tab in the Cypress Programming Solutions web page) for details of how to put the Pioneer Kit into DAPLink mode.

Software Setup

This example requires CapSense Tuner, which is installed as part of ModusToolbox software v2.1. Refer to the ModusToolbox Installation Guide for installation instructions.

Install a terminal emulator if you don’t have one. Instructions in this document use Tera Term.

This example requires no additional software or tools.

Import the Code Example Using Mbed CLI Tool

Mbed CLI commands are used to import the code example and compile. See Working with Mbed CLI web page.

  1. Run the following command:

mbed import

This command first clones the code example repository from GitHub, and then deploys all the libraries. If you wish to perform the deploy process manually, run the following commands:

  1. Clone the GitHub code example repository:

    git clone && cd mbed-os-example-capsense

  2. Deploy the dependent libraries. The library files are identified with .lib extension.

    mbed deploy

  3. Set the current directory as root:

mbed new .


  1. Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.

  2. Program the board.

    mbed compile -m <TARGET> -t <TOOLCHAIN> --flash --sterm

    For example, to build for the target CY8CPROTO_062_4343W with GCC_ARM toolchain, use the following command:

    mbed compile -m CY8CPROTO_062_4343W -t GCC_ARM --flash --sterm

Note: With the --sterm option, Mbed CLI opens a new terminal with 9600-8N1 as the setting after programming completes. Do not use this option if you want to connect using another serial terminal application such as PuTTY or Tera Term.

  1. After programming, the application starts automatically. Confirm that the terminal application displays the message as shown in Figure 1.

Figure 1. Output in UART Terminal

Figure 1

  1. Touch the buttons or the slider to observe the User LED changing its state (ON when touched and OFF when not touched) and the status printed on the serial terminal

Figure 2. Output in UART Terminal When Button or Slider is Touched

Figure 2

  1. You can also monitor the CapSense data using the CapSense Tuner application as follows:

Monitor Data Using CapSense Tuner

  1. Enable the Tuner functionality by configuring the value of the TUNER_ENABLE macro in main. cpp to 1.

  2. Open \/ModusToolbox/tools_2.1/capsense-configurator/capsense-tuner to run the CapSense Tuner application.

  3. Select File > Open and open the design.cycapsense file in the example directory for the respective kit, in \/mbed-os/targets/TARGET_Cypress/TARGET_PSOC6/TARGET_\/COMPONENT_CUSTOM_DESIGN_MODUS/design.cycapsense.

  4. Switch the kit from DAPLink mode to KitProg3 mode. See Firmware-loader to learn on how to update the firmware and switch to KitProg3 mode.

  5. In the Tuner application, click Tuner Communication Setup or select Tools > Tuner Communication Setup. In the window that appears, select the I2C checkbox under KitProg3 and configure as follows:

  • I2C Address: 8
  • Sub-address: 2-Bytes
  • Speed (kHz): 400
  1. Click Connect or select Communication > Connect.

  2. Click Start or select Communication > Start.

Under the Widget View tab, you can see the corresponding widgets highlighted in blue colour when you touch the button or slider. You can also view the sensor data in the Graph View tab. For example, to view the sensor data for Button 0, select Button0_Rx0 under Button0.

Figure 3 shows the CapSense Tuner displaying the status of CapSense touch on Button0 and LinearSlider0.

Figure 3. CapSense Tuner Showing Touch Data

See the ModusToolbox CapSense Tuner Guide (Help > View Help) for more information.


You can debug the example to step through the code. In the IDE, use the \ 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.

Follow the steps from Eclipse IDE for ModusToolbox User Guide to export the Mbed OS code example and import it into Eclipse IDE for ModusToolbox for programming and debugging.

Mbed OS also supports debugging using any IDE that supports GDB. See Arm Mbed documentation.

Note: (Only while debugging) On the CM4 CPU, some code in main() may execute before the debugger halts at the beginning of main(). This means that some code executes twice - once before the debugger stops execution, and again after the debugger resets the program counter to the beginning of main(). See KBA231071 to learn about this and for the workaround.

Design and Implementation

In this project, PSoC 6 MCU scans a self-capacitance (CSD) based, 5-element CapSense slider and two mutual capacitance (CSX) CapSense buttons for user input. The project uses the CapSense middleware; see ModusToolbox User Guide for details on selecting the middleware. See AN85951 – PSoC 4 and PSoC 6 MCU CapSense Design Guide for more details of CapSense features and usage.

This example turns the user LED ON when any of the widgets is touched, and OFF when none of them are touched, and prints the button status and slider position over the serial port.

The application uses an EZI2C HAL interface for communicating with the CapSense Tuner. This example uses the following RTOS objects and runs a thread for periodic CapSense scan apart from the main() thread.

Semaphore: The scan loop calls acquire() to acquire a semaphore while initiating the scan. In the subsequent loops, the program waits to acquire the semaphore before initiating the next scan and processes the touch information. The semaphore is released at the end of the scan callback.

EventQueue: The dispatcher of the EventQueue is run inside a thread to periodically scan the sensors.

The ModusToolbox CapSense Configurator Tool Guide describes step-by-step instructions on how to launch and use CapSense Configurator in ModusToolbox. This tool can be launched in Eclipse IDE for ModusToolbox from the CSD personality, as well as in stand-alone mode.

Operation at a Custom Power Supply Voltage

Table 1 lists the power supply voltages supported by each kit along with the default operating voltage.

Table 1. Operating Voltages Supported by the Kits

Kit Supported Operating Voltages Default Operating Voltage
CY8CPROTO-062-4343W 3.3 V / 1.8 V 3.3 V
CY8CKIT-062-BLE 3.3 V / 1.8 V 3.3 V
CY8CKIT-062-WIFI-BT 3.3 V / 1.8 V 3.3 V
CY8CKIT-062S2-43012 3.3 V / 1.8 V 3.3 V
CYW9P62S1-43438EVB-01 3.3 V Only 3.3 V
CYW9P62S1-43012EVB-01 1.8 V Only 1.8 V
CY8CPROTO-062S3-4343W 3.3 V / 1.8 V 3.3 V

For the kits that support multiple operating voltages, do the following to work at a custom power supply, such as 1.8 V:

  1. Open //ModusToolbox/tools_2.1/device-configurator/device-configurator to run the Device Configurator tool.

  2. Select File > Open. Navigate to and open design.modus file for the respective kit: \/mbed-os/targets/TARGET_Cypress/TARGET_PSOC6/TARGET_\/COMPONENT_CUSTOM_DESIGN_MODUS/design.modus.

  3. Update the operating conditions as shown in Figure 4 and select File > Save.

Figure 4. Power Settings to Work with 1.8 V

  1. Change the jumper/switch setting as listed in Table 2.

Table 2. Jumper/Switch Position for 1.8 V Operation

| Kit                   | Jumper/Switch Position         |
| CY8CPROTO-062-4343W   | J3 (1-2)                       |
| CY8CKIT-062-BLE       | SW5 (1-2)                      |
| CY8CKIT-062-WIFI-BT   | SW5 (1-2)                      |
| CY8CKIT-062S2-43012   | J14 (1-2)                      |
| CYW9P62S1-43438EVB-01 | J14 (1-2)                      |
| CYW9P62S1-43012EVB-01 | J14 (1-2)                      |
| CY8CPROTO-062S3-4343W | J3 (1-2)                       |
  1. Re-build and program the application to evaluate the application at the new power setting.

Resources and Settings

Table 1. Application Resources

Resource Alias/Object Purpose
Capsense (Middleware) cy_capsense_context CapSense middleware instance
EZI2C (HAL) sEzI2C Slave EZI2C object used to tune CapSense

Related Resources

Application Notes
AN228571 – Getting Started with PSoC 6 MCU on ModusToolbox Describes PSoC 6 MCU devices and how to build your first application with ModusToolbox
AN221774 – Getting Started with PSoC 6 MCU on PSoC Creator Describes PSoC 6 MCU devices and how to build your first application with PSoC Creator
AN210781 – Getting Started with PSoC 6 MCU with Bluetooth Low Energy (BLE) Connectivity on PSoC Creator Describes PSoC 6 MCU with BLE Connectivity devices and how to build your first application with PSoC Creator
AN215656 – PSoC 6 MCU: Dual-CPU System Design Describes the dual-CPU architecture in PSoC 6 MCU, and shows how to build a simple dual-CPU design
AN85951 – PSoC 4 and PSoC 6 MCU CapSense Design Guide The PSoC 4 and PSoC 6 MCU CapSense Design Guide shows how to design capacitive touch sensing applications with the PSoC 4, PSoC 6 families of devices
Code Examples
Using ModusToolbox Using PSoC Creator
Device Documentation
PSoC 6 MCU Datasheets PSoC 6 Technical Reference Manuals
Development Kits Buy at
CY8CKIT-062-BLE PSoC 6 BLE Pioneer Kit CY8CKIT-062-WiFi-BT PSoC 6 WiFi-BT Pioneer Kit
CY8CPROTO-063-BLE PSoC 6 BLE Prototyping Kit CY8CPROTO-062-4343W PSoC 6 Wi-Fi BT Prototyping Kit
CY8CKIT-062S2-43012 PSoC 62S2 Wi-Fi BT Pioneer Kit CY8CPROTO-062S3-4343W PSoC 62S3 Wi-Fi BT Prototyping Kit
CYW9P62S1-43438EVB-01 PSoC 62S1 Wi-Fi BT Pioneer Kit CYW9P62S1-43012EVB-01 PSoC 62S1 Wi-Fi BT Pioneer Kit
PSoC 6 Peripheral Driver Library (PDL) and docs psoc6pdl on GitHub
Cypress Hardware Abstraction Layer (HAL) Library and docs psoc6hal on GitHub
Retarget IO - A utility library to retarget the standard input/output (STDIO) messages to a UART port retarget-io on GitHub
CapSense® library and docs capsense on GitHub
Links to all PSoC 6 MCU Middleware psoc6-middleware on GitHub
Eclipse IDE for ModusToolbox The cross-platform, Eclipse-based IDE for IoT designers that supports application configuration and development targeting converged MCU and wireless systems.
PSoC Creator™ The Cypress IDE for PSoC and FM0+ MCU development.

Other Resources

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

For PSoC 6 MCU devices, see How to Design with PSoC 6 MCU - KBA223067 in the Cypress community.

Document History

Document Title: CE226594 - PSoC 6 MCU CapSense Buttons and Slider

Version Description of Change
1.0.0 Initial release.
Tested with mbed-os v5.11.4 and CapSense middleware v1.2
1.1.0 Minor update.
Tested with mbed-os v5.13.1 and CapSense middleware v2.0
1.2.0 Updated to work with CapSense Tuner in ModusToolbox 1.1
Tested with mbed-os v5.14 and CapSense middleware v2.0
1.3.0 Updated to work with CapSense Tuner in ModusToolbox 2.0
Tested with mbed-os v5.14.1 and CapSense middleware v2.0
Updated Monitor data using CapSense Tuner section
Added Operation at custom power supply section
Added Design and Implementation section
1.4.0 Readme updates.
Re-structured custom TARGET folders
Added support for CYW9P62S1-43438EVB-01 and CYW9P62S1-43012EVB-01
Added deep sleep callbacks for supporting tickless operation
Tested with mbed-os v5.15.1 and CapSense middleware v2.0
This update is not backward compatible with Mbed OS versions < 5.15.1
2.0.0 Updated to Mbed OS 6.2.
Major code changes - Updated to use EzI2C HAL for CapSense Tuner interface

All other trademarks or registered trademarks referenced herein are the property of their respective owners.


© Cypress Semiconductor Corporation, 2020. This document is the property of Cypress Semiconductor Corporation and its subsidiaries (“Cypress”). This document, including any software or firmware included or referenced in this document (“Software”), is owned by Cypress under the intellectual property laws and treaties of the United States and other countries worldwide. Cypress reserves all rights under such laws and treaties and does not, except as specifically stated in this paragraph, grant any license under its patents, copyrights, trademarks, or other intellectual property rights. If the Software is not accompanied by a license agreement and you do not otherwise have a written agreement with Cypress governing the use of the Software, then Cypress hereby grants you a personal, non-exclusive, nontransferable license (without the right to sublicense) (1) under its copyright rights in the Software (a) for Software provided in source code form, to modify and reproduce the Software solely for use with Cypress hardware products, only internally within your organization, and (b) to distribute the Software in binary code form externally to end users (either directly or indirectly through resellers and distributors), solely for use on Cypress hardware product units, and (2) under those claims of Cypress’s patents that are infringed by the Software (as provided by Cypress, unmodified) to make, use, distribute, and import the Software solely for use with Cypress hardware products. Any other use, reproduction, modification, translation, or compilation of the Software is prohibited.
TO THE EXTENT PERMITTED BY APPLICABLE LAW, CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS DOCUMENT OR ANY SOFTWARE OR ACCOMPANYING HARDWARE, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. No computing device can be absolutely secure. Therefore, despite security measures implemented in Cypress hardware or software products, Cypress shall have no liability arising out of any security breach, such as unauthorized access to or use of a Cypress product. CYPRESS DOES NOT REPRESENT, WARRANT, OR GUARANTEE THAT CYPRESS PRODUCTS, OR SYSTEMS CREATED USING CYPRESS PRODUCTS, WILL BE FREE FROM CORRUPTION, ATTACK, VIRUSES, INTERFERENCE, HACKING, DATA LOSS OR THEFT, OR OTHER SECURITY INTRUSION (collectively, “Security Breach”). Cypress disclaims any liability relating to any Security Breach, and you shall and hereby do release Cypress from any claim, damage, or other liability arising from any Security Breach. In addition, the products described in these materials may contain design defects or errors known as errata which may cause the product to deviate from published specifications. To the extent permitted by applicable law, Cypress reserves the right to make changes to this document without further notice. Cypress does not assume any liability arising out of the application or use of any product or circuit described in this document. Any information provided in this document, including any sample design information or programming code, is provided only for reference purposes. It is the responsibility of the user of this document to properly design, program, and test the functionality and safety of any application made of this information and any resulting product. “High-Risk Device” means any device or system whose failure could cause personal injury, death, or property damage. Examples of High-Risk Devices are weapons, nuclear installations, surgical implants, and other medical devices. “Critical Component” means any component of a High-Risk Device whose failure to perform can be reasonably expected to cause, directly or indirectly, the failure of the High-Risk Device, or to affect its safety or effectiveness. Cypress is not liable, in whole or in part, and you shall and hereby do release Cypress from any claim, damage, or other liability arising from any use of a Cypress product as a Critical Component in a High-Risk Device. You shall indemnify and hold Cypress, its directors, officers, employees, agents, affiliates, distributors, and assigns harmless from and against all claims, costs, damages, and expenses, arising out of any claim, including claims for product liability, personal injury or death, or property damage arising from any use of a Cypress product as a Critical Component in a High-Risk Device. Cypress products are not intended or authorized for use as a Critical Component in any High-Risk Device except to the limited extent that (i) Cypress’s published data sheet for the product explicitly states Cypress has qualified the product for use in a specific High-Risk Device, or (ii) Cypress has given you advance written authorization to use the product as a Critical Component in the specific High-Risk Device and you have signed a separate indemnification agreement.
Cypress, the Cypress logo, Spansion, the Spansion logo, and combinations thereof, WICED, PSoC, CapSense, EZ-USB, F-RAM, and Traveo are trademarks or registered trademarks of Cypress in the United States and other countries. For a more complete list of Cypress trademarks, visit Other names and brands may be claimed as property of their respective owners.