This code example demonstrates an implementation of capacitive sensors to measure the depth of water-based liquids in nonconductive containers. Mounted on or near the container exterior, these sensors provide accurate, real-time monitoring of liquid fill levels, while also rejecting foam interference and eliminating the need for physical contact with the liquid.
Note: When using the liquid level sensing flex PCB provided with the kit, this code example delivers efficient performance for liquid level detection. However, it provides less efficient and less accurate results for foam rejection due to the thin flex PCB used. For applications that require reliable foam rejection, it is highly recommended to use FR4 PCBs. If flex PCBs must be used, thicker flex PCBs are advised to reduce parasitic capacitance between the active sensors and the shield..
Provide feedback on this code example.
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ModusToolbox™ v3.7 or later
Note: This code example requires ModusToolbox™ v3.7 and is not backward compatible with older versions
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ModusToolbox™ CAPSENSE™ and Multi-Sense Pack for ModusToolbox™ v3.7 or later
Note: This pack contains CAPSENSE™ Configurator, CAPSENSE™ Tuner and Sensor designer tools.
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Board support package (BSP) minimum required version: 3.3.0
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Programming language: C
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Associated parts: PSOC™ 4000T, PSOC™ 4100T Plus
- GNU Arm® Embedded Compiler v11.3.1 (
GCC_ARM) – Default value ofTOOLCHAIN - Arm® Compiler v6.22 (
ARM) - IAR C/C++ Compiler v9.50.2 (
IAR)
- PSOC™ 4000T Multi-Sense Prototyping Kit (
CY8CPROTO-040T-MS) – Default value ofTARGET - PSOC™ 4100T Plus CAPSENSE™ Prototyping Kit (
CY8CPROTO-041TP)
This example uses the board's default configuration. See the kit user guide to configure the required operating voltage on the kit and to setup the VDDA supply voltage, see the Set up the VDDA supply voltage and debug mode in Device Configurator section.
This application is tuned to perform optimally at the default voltage. However, you can observe the basic functionality at other supported voltages.
Note: Some PSOC™ 4 kits ship with KitProg2 installed. ModusToolbox™ 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".
See the ModusToolbox™ tools package installation guide for information about installing and configuring the tools package.
This example requires no additional software or tools.
The ModusToolbox™ tools package provides the Project Creator as both a GUI tool and a command line tool.
Use Project Creator GUI
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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)
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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
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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 CAPSENSE LLS" application with the desired name "MyLLS" configured for the CY8CPROTO-040T-MS BSP into the specified working directory, C:/mtb_projects:
project-creator-cli --board-id CY8CPROTO-040T-MS --app-id mtb-example-psoc4-msclp-lls --user-app-name MyLLS --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 cloneandmake getlibscommands 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).
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).
Arm® Keil® µVision®
Double-click the generated {project-name}.cprj file to launch the Keil® µVision® IDE.
For more details, see the Arm® 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).
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Ensure the board is connected with the liquid level sensing flex PCB
Note: If a custom container is used other than the bottle provided with the kit, the system may need a liquid level factory calibration as mentioned in the Perform liquid level calibration section
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Connect the board to your PC using the provided USB cable through the KitProg3 USB connector
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Program the board using one of the following:
Note: It is essential to completely empty the tank before programming to ensure accurate one-time calibration. See the One-time factory auto-calibration section for further details
Using Eclipse IDE
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Select the application project in the Project Explorer
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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 programcommand 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 -
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After programming, the application starts automatically
Note: After programming, you may see the following error message if debug mode is disabled, see Table 7 of the Debugging section for the default debug configuration in the supported kits. Ignore the error or enable debug mode to solve it
"Error: Error connecting Dp: Cannot read IDR" -
To test the application, observe the LED behavior as shown in Table 1
Table 1. LED indications and status
| Scenario | CY8CPROTO-040T-MS | CY8CPROTO-041TP | LED Status |
|---|---|---|---|
| Tank detected | LED2 | LED2 | ON |
| Liquid Presence detected (60 mm) | LED2 & LED3 | LED2 & LED3 | ON |
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Open CAPSENSE™ Tuner from the IDE Quick Panel of the Eclipse IDE for ModusToolbox™
Or
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 start CAPSENSE™ Tuner using the CLI
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Ensure the status LED is on and not blinking, which indicates that the onboard KitProg3 is in CMSIS-DAP bulk mode. See Firmware-loader to learn how to update the firmware and switch modes in KitProg3
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In the Tuner application, select Tools > Tuner Communication setupor click on the Tuner Communication Setup icon
In the window that appears, 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
Figure 1. Tuner communication setup parameters
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Select Communication > Connect or click the Connect icon to establish a connection
Figure 2. Establish connection
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Select Communication > Start or Click the Start icon to start streaming data from the device
Figure 3. 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
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Set the Read mode as Synchronized. Navigate to the Widget View tab and observe the needle in the Liquid_Level_Sensor_FR widget changing as you pour or remove water in the container
Figure 4. Widget view of the CAPSENSE™ Tuner
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Add a layer of foam on top of the liquid, facilitated by a surfactant, and observe how the liquid level remains unaffected by the foam, as reported by the Liquid_Level_Sensor_FR widget. This demonstrates the system's ability to reject foam and maintain accurate liquid level sensing
Figure 5. Widget view of CAPSENSE™ Tuner
Note: The level in the Liquid_Level_Sensor changes due to the foam as it is a normal liquid level sensor and does not incorporate the foam rejection capability
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View the raw counts of the liquid level sensors through the Graph View tab. The normal liquid level and foam-rejected liquid level can be observed in the position window
Figure 6. Liquid level sensor position
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Switch to the SNR Measurement tab and verify that the SNR is above 20:1 by performing the following steps:
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Select the Liquid_Level_0_Sns0 sensor under the Liquid_Level_0 widget and click Acquire Noise, as shown in Figure 7. Repeat the same (Acquire Noise) for all sensors under the Liquid_Level_0 widget
Figure 7. CAPSENSE™ Tuner - SNR measurement: Acquire noise
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Fill the tank to the maximum level, Select the Liquid_Level_0_Sns0 sensor under the Liquid_Level_0 widget, and click Acquire Signal, as shown in Figure 8 and wait for the SNR measurement to complete. Repeat the same (Acquire Signal) for all the sensors under the Liquid_Level_0 widget
Figure 8. CAPSENSE™ Tuner - SNR measurement: Acquire Signal
Ensure the SNR is above 20:1
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Create a custom BSP for your board
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Create a custom BSP for your board for any device by following the steps given in ModusToolbox™ BSP Assistant user guide. This code example is created for the CY8C4046LQI-T452 device
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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
Note: See the "Selecting CAPSENSE™ hardware parameters" section in AN85951 – PSOC™ 4 and PSOC™ 6 MCU CAPSENSE™ design guide to learn the considerations for selecting each parameter value.
The tuning flow of the Liquid level sensing widget is shown in Figure 9.
Figure 9. Tuning flow of liquid level sensor
Perform the following steps to tune the liquid level sensing widget:
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Connect the board to your PC using the provided USB cable through the KitProg3 USB connector
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Launch the Device Configurator tool
Launch it in the Eclipse IDE for ModusToolbox™ from the Quick Panel
Or
Launch it 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
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Enable the CAPSENSE™ channel in the Device Configurator tool, as shown in Figure 10:
Figure 10. Enable CAPSENSE™ in Device Configurator
Save the changes and close the window
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Launch the CAPSENSE™ Configurator tool
Launch it in Eclipse IDE for ModusToolbox™ through the "CAPSENSE™" peripheral setting in the Device Configurator or directly from the IDE Quick Panel
Or
Launch it in standalone mode through {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 present in the {Application root directory}/bsps/TARGET_APP_<BSP-NAME>/config folder
See the ModusToolbox™ CAPSENSE™ Configurator user guide for step-by-step instructions on how to configure and launch CAPSENSE™ in ModusToolbox™
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In the Basic tab, configure a Liquid Level Sensing widget as a CSD RM (self-capacitance). The Liquid Level sensing widget comprises a number of sensing elements called segments. The widget uses the data from each segment to calculate the liquid level
Figure 11. CAPSENSE™ Configurator - Basic tab
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Set the following in the Advanced > General tab:
Table 2. Widget details
Parameter Setting Description CAPSENSE™ IMO clock frequency (MHz) 46 IMO clock frequency Modulator clock divider 1 Set to obtain the optimum modulator clock frequency Number of init sub-conversions 3 Set to ensure proper initialization of CAPSENSE™ Enable CIC2 hardware filter TRUE Enabling CIC2 filter helps in higher SNR
Figure 12. CAPSENSE™ Configurator - General settings
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Go to the CSD Settings tab and make the following changes:
Table 3. Scan settings
Parameter CY8CPROTO-040T-MS Description Inactive sensor connection Shield Connects the inactive sensors (configured sensors that have not been scanned in a given scan slot) to the driven shield Shield mode Active The driven shield is a signal that replicates the sensor-switching signal. It helps reduce the sensor parasitic capacitance Total shield count 2 Selects the number of shield electrodes used in the design. Most designs work with one dedicated shield electrode, but some designs require multiple dedicated shield electrodes to ease the PCB layout routing or minimize the PCB area used for the shield layer Raw count calibration level (%) 40 If the sensor raw count saturates (equals maximum raw count) on water covering the sensor, reduce the raw count calibration level (%). This prevents raw count saturation
Figure 13. CAPSENSE™ Configurator - Advanced CSD settings
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Go to the Widget Details tab
Select the LiquidLevel0 from the left pane and set the following:
Table 4. Initial widget parameter setting LiquidLevel0
Parameter Setting Description Enable foam rejection true This is to enable the Foam Rejection Widget for the Foam Rejection functionality Enable tank removal detection true This is to identify if the physical tank connected to the device has been removed or is not present Maximum level 120 Set this value to a multiple of the total depth of the tank. For example, this project uses a 12 cm tank. Therefore, the value may be 120, 240, or 1200; however, this project has used 120, for every 1 count, 1 mm is measured Sense clock divider Default Value is set in Stage 2: Set sense clock frequency Clock source Direct Direct clock is a constant frequency sense clock source. When you choose this option, the sensor pin switches with a constant frequency Number of sub-conversions 60 Good starting point to ensure a fast scan time and sufficient signal. This value has to be adjusted as required in Stage 3: Fine-tune for required SNR Reference CDAC mode Auto Set it to Auto for initial auto-calibration Reference CDAC boost Disable Not required Fine CDAC mode Auto Set it to Auto for initial auto-calibration Compensation CDAC mode Auto Set it to Auto for initial auto-calibration Compensation CDAC divider mode Auto Set it to Auto for initial auto-calibration CDAC dither mode Disable Not required IIR filter False Not required Median filter True Essential to remove sudden spikes in the level measurement due to calculation errors Average filter True Removes periodic noises like noise from AC mains Jitter filter True Removes toggling of the position data
Figure 14. CAPSENSE™ Configurator - Liquid Level Sensor widget details
Select the LiquidLevel0_FR from the left pane and set the following:
Table 5. Initial widget parameter setting LiquidLevel0_FR
Parameter Setting Description Foam correction coefficient 64 To compensate for the foam correction level. To accurately calculate this value, follow the steps mentioned in the "Foam rejection coefficient calculation" section of AN239805 – Liquid-level sensing with PSOC™ 4 CAPSENSE™ Maximum level Same as LiquidLevel0 widget – Sense clock divider Same as LiquidLevel0 widget – Clock source Same as LiquidLevel0 widget – Number of sub-conversions 2X of LiquidLevel0 General guidance is to set the number of sub-conversions to twice the number of sub-conversions for the base widget Reference CDAC mode Auto Set it to Auto for initial auto-calibration Reference CDAC boost Disable Not required Fine CDAC mode Auto Set it to Auto for initial auto-calibration Compensation CDAC mode Auto Set it to Auto for initial auto-calibration Compensation CDAC divider mode Auto Set it to Auto for initial auto-calibration CDAC dither mode Disable Not required IIR filter False Not required Median filter True Essential to remove sudden spikes in the level measurement due to calculation errors Average filter True Removes periodic noise like noise from AC mains Jitter filter True Removes toggling of the position data
Figure 15. CAPSENSE™ Configurator - Liquid Level Foam Rejection widget details
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Go to the Scan Configuration tab to select the pins and scan slots. Configure the pins for electrodes using the drop down menu
Ensure that the bottom-most sensor is considered as Sensor 0 (Sns0) and the top-most sensor is considered as Sensor N (SnsN)
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The electrodes for the liquid level foam rejection widget LiquidLevel0_FR are the same as that of the liquid level widget LiquidLevel0, so the sensor electrodes of LiquidLevel0 are simply ganged to LiquidLevel0_FR widget's sensor electrodes
Figure 16. CAPSENSE™ Configurator – Scan Configuration tab
The sense clock is derived from the modulator clock using a sense 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 so that the pulse width of the sense clock is long enough to let the sensor capacitance 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 17 and Figure 18 for waveforms observed on the sensors. Figure 17 shows the proper charging when the sense clock frequency is correctly tuned. Adjust the sense clock divider so the voltage reaches at least 99.3% of VDDD in Phase 1, or VDDD/2 in Phase 0, as Figure 18 shows.
Figure 17. Proper charge cycle of a sensor
Figure 18. Improper charge cycle of a sensor
To set the proper sense clock frequency:
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Program the board and launch CAPSENSE™ Tuner
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Observe the charging waveform of the sensor and shield as described earlier
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If the charging is incomplete, increase the sense clock divider. Do this in CAPSENSE™ Tuner by selecting the widget 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 you observe complete settling > - Using a passive probe will add an additional parasitic capacitance of around 15 pF; therefore, it should be considered while tuning
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Click Apply to Project to save the configuration to your project
Figure 19. Sense clock divider setting
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Repeat this process for all the sensors and the shield. Each sensor may require a different sense clock divider value to charge or discharge completely. But all the sensors under the same widget need to have the same sense clock source, sense clock divider, and number of sub-conversions. Therefore, consider the largest sense clock divider required by the sensor for that widget
Note: Typically, shields require a high sense clock divider. Because this project utilizes a shield, obtain the required sense clock divider for the shield. If it is higher than the liquid level sensor widget, set the same sense clock divider for the liquid level sensor widget as well
Table 6. Sense clock divider settings obtained for supported kits
Parameter CY8CPROTO-040T-MS CY8CPROTO-041TP Sense clock divider 128 128
The sensor must provide a large signal for the processing function to accurately calculate the liquid level. Liquid level sensing systems perform best with signal-to-noise ratio (SNR) values 10 or higher. The sensitivity can be increased by increasing the number of sub-conversions and noise can be decreased by enabling available filters. This section demonstrates using CAPSENSE™ Tuner and Configurator to measure and adjust the SNR.
Follow these steps for optimizing these parameters:
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Measure the SNR as mentioned in Step 9 of the Operation section
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If the SNR is less than 20:1, increase the number of sub-conversions. Edit the number of sub-conversions (Nsub) directly in the Widget/Sensor parameters tab of the CAPSENSE™ Tuner and click on Apply to Device
Note: Number of sub-conversion should be >= 8
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Repeat steps 1 and 2 until the Measured SNR is greater than 20:1
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If the system is noisy (>40% of signal), enable filters
Enable the IIR filter for noise reduction
To enable and configure filters available in the system:
a. Open CAPSENSE™ Configurator from ModusToolbox™ Quick Panel and select the appropriate filter
Figure 20. Filter settings in CAPSENSE™ Configurator
Note: Add the filter based on the type of noise in your measurements. See ModusToolbox™ CAPSENSE™ Configurator user guide for details
b. Click Save and close CAPSENSE™ Configurator. Program the device to update the filter settings
Note: Increasing the number of sub-conversions and enabling filters increases the scan time, which in turn reduces sensor responsiveness and increases power consumption. Therefore, the number of sub-conversions and filter configuration must be optimized to achieve a balance between SNR, power, and refresh rate
After completing the sensor tuning procedure for the expected SNR as mentioned in Stage 3: Fine-tune for required SNR, perform the liquid level calibration to train the system for level measurement.
This code example is pre-calibrated to be used with the standard liquid level sensing kit, offering a calibration range of 120 mm and a resolution of 1 mm.
For a detailed procedure on the liquid level calibration, see the Liquid-level calibration procedure section of AN239805 – Liquid-level sensing with PSOC™ 4 CAPSENSE™.
This feature detects if a physical tank is connected to the device or removed – it is enabled in this code example.
For more details on this feature, see the Tank Removal Detection section of AN239805 – Liquid-level sensing with PSOC™ 4 CAPSENSE™.
The liquid presence detection feature reports the presence of a liquid, based on a pre-configured threshold. This feature can be enabled using either the Liquid Level widget or the Liquid Presence widget;Figure 21 shows the Liquid Presence widget view in CAPSENSE™ Tuner.
Figure 21. Liquid presence widget view of the CAPSENSE™ Tuner
For more details on this feature, including compatible widgets and threshold configuration guidelines see the Liquid Presence detection section of the Liquid-level sensing with PSOC™ 4 CAPSENSE™.
The CAPSENSE™-based liquid-level sensing system uses frozen CDAC values, which can vary across devices and sensing setups. This impacts the level measurement accuracy. To account for these variations, use this one-time factory auto-calibration.
This helps to improve measurement accuracy by handling part-to-part variations and minor mechanical variations on sensor placement.
This code example has this one-time factory auto-calibration feature enabled at the application level. It will get calibrated during the first power on after flashing and values are stored in EEPROM.
Note: It is essential to completely empty the tank attached.
For details on one-time auto-calibration, see the One-time factory auto-calibration section of AN239805 – Liquid-level sensing with PSOC™ 4 CAPSENSE™.
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.
To enable the debug option, see the Setup VDDA and debug mode in Device Configurator section. To achieve lower power consumption, it is recommended to disable it when not debugging.
See Table 7 for the default debug configuration in the supported kits.
Table 7. Debug mode option status
| Kit | Debug mode |
|---|---|
| CY8CPROTO-040T-MS | Enabled |
| CY8CPROTO-041TP | Enabled |
The project uses CAPSENSE™ middleware; see the 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.
See AN239805 – Liquid-level sensing with PSOC™ 4 CAPSENSE™ for complete details on how to create a liquid level sensing system using CAPSENSE™. It also discusses how to design the liquid level sensors.
This code example uses a liquid level sensing widget along with its liquid level sensing foam rejection sub-widget to accurately measure the liquid level in the bottle as provided with the Liquid Level Sensing Kit. The Liquid level sensing foam rejection sub-widget provides accurate liquid level measurements while rejecting foam interference.
Figure 22. Liquid level sensor widget
Figure 23. Liquid level sensor foam rejection sub-widget
The design also has an EZI2C peripheral. The EZI2C slave peripheral is used to monitor the information of a sensor's raw and processed data on a PC using the CAPSENSE™ Tuner available in the Eclipse IDE for ModusToolbox™ via I2C communication.
The firmware scans the liquid level sensing widget and the liquid level sensing foam rejection sub-widget indefinitely. The scan results are then processed and sent to the CAPSENSE™ Tuner via the EZI2C bus. The level then can be seen under the Position window of the CAPSENSE™ Tuner.
Note: In the current project, the liquid level sensing widget and the liquid level sensing foam rejection sub-widget are scanned separately and needs to be scanned separately; they will not work if scanned together by calling
Cy_CapSense_ScanAllWidgetsdue to architectural limitations. This will get resolved in upcoming releases.
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Open Device Configurator tool from the Quick Panel of the Eclipse for ModusToolbox™
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Go to the System tab. Select the Power resource and set the VDDA value under Operating conditions as shown in Figure 24
Figure 24. Setting the VDDA supply in the System tab of Device Configurator
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By default, the debug mode is disabled for this application to reduce power consumption. Enable the debug mode to enable the SWD pins, as shown in Figure 25:
Figure 25. Enable Debug mode in the System tab of Device Configurator
Figure 26. EZI2C settings
Table 8. Application resources
| Resource | Alias/object | Purpose |
|---|---|---|
| SCB (EZI2C) (PDL) | CYBSP_EZI2C | EZI2C slave driver to communicate with CAPSENSE™ Tuner |
| CAPSENSE™ (MSCLP0) | CYBSP_MSCLP0 | CAPSENSE™ driver to interact with the MSCLP hardware and interface the CAPSENSE™ sensors |
Figure 27. Firmware flowchart
| Resources | Links |
|---|---|
| Application notes | AN79953 – Getting started with PSOC™ 4 AN85951 – PSOC™ 4 and PSOC™ 6 MCU CAPSENSE™ design guide AN239805 – Liquid-level sensing with PSOC™ 4 CAPSENSE™ AN234231 – PSOC™ 4 CAPSENSE™ ultra-low-power capacitive sensing techniques AN92239 – Proximity sensing with CAPSENSE™ |
| 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) |
| Middleware on GitHub | capsense – CAPSENSE™ library and documents psoc4-middleware – Links to all PSOC™ 4 middleware |
| 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. |
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 title: CE240535 – PSOC™ 4: MSCLP CAPSENSE™ liquid level sensing
| Version | Description of change |
|---|---|
| 1.0.0 | New code example |
| 2.0.0 | Major update to support ModusToolbox™ v3.3. This version is not backward compatible with previous versions of ModusToolbox™ |
| 2.1.0 | Removed foam rejection calibration process |
| 3.0.0 | Added support for CY8CPROTO-041TP Prototyping Kit. Major update to support ModusToolbox™ v3.5. This version is not backward compatible with previous versions of ModusToolbox™ |
| 4.0.0 | Added one-time auto-calibration feature Major update to support ModusToolbox™ v3.6. This version is not backward compatible with previous versions of ModusToolbox™ |
| 5.0.0 | Added tank removal detection and liquid level presence feature Major update to support ModusToolbox™ v3.7. This version is not backward compatible with previous versions of ModusToolbox™ |
| 6.0.0 | Middleware version updated |
All referenced product or service names and trademarks are the property of their respective owners.
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