This code example demonstrates the low-power analog features of PSoC™ 6 MCU using an OpAmp and SAR ADC. This example is supported only for the device such as CY8C62x4 which has an OpAmp and SAR ADC capable of operating in System Deep Sleep mode. The analog components - OpAmp and SAR ADC - are configured to operate when the system is in Deep Sleep mode.
In this example, the SAR ADC samples the input voltage provided at pin P9.0. When the number of samples in the FIFO becomes equal to the preconfigured number of samples, an interrupt is raised; the system switches to normal mode. The acquired data is moved from the FIFO to a buffer using DMA. When the specified number of samples are collected in the buffer, they are averaged and displayed on the UART.
Provide feedback on this code example.
- ModusToolbox™ software v3.0 or later (tested with v3.0)
- Board support package (BSP) minimum required version: 4.0.0
- Programming language: C
- Associated parts: All CY8C62x4 parts
- GNU Arm® embedded compiler v10.3.1 (
GCC_ARM) - Default value ofTOOLCHAIN - Arm® compiler v6.16 (
ARM) - IAR C/C++ compiler v9.30.1 (
IAR)
- PSoC™ 62S4 pioneer kit (
CY8CKIT-062S4)
This example uses the board's default configuration. See the kit user guide to ensure that the board is configured correctly.
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.
Create the project and open it using one of the following:
In Eclipse IDE for ModusToolbox™ software
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Click the New Application link in the Quick Panel (or, use File > New > ModusToolbox™ Application). This launches the Project Creator tool.
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Pick a kit supported by the code example from the list shown in the Project Creator - Choose Board Support Package (BSP) dialog.
When you select a supported kit, the example is reconfigured automatically to work with the kit. To work with a different supported kit later, use the Library Manager to choose the BSP for the supported kit. You can use the Library Manager to select or update the BSP and firmware libraries used in this application. To access the Library Manager, click the link from the Quick Panel.
You can also just start the application creation process again and select a different kit.
If you want to use the application 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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In the Project Creator - Select Application dialog, choose the example by enabling the checkbox.
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(Optional) Change the suggested New Application Name.
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The Application(s) Root Path defaults to the Eclipse workspace which is usually the desired location for the application. If you want to store the application in a different location, you can change the Application(s) Root Path value. Applications that share libraries should be in the same root path.
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Click Create to complete the application creation process.
For more details, see the Eclipse IDE for ModusToolbox™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mt_ide_user_guide.pdf).
In command-line interface (CLI)
ModusToolbox™ software provides the Project Creator as both a GUI tool and the command line tool, "project-creator-cli". The 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™ software 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™ software installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ software 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 "project-creator-cli" tool has the following arguments:
| Argument | Description | Required/optional |
|---|---|---|
--board-id |
Defined in the <id> field of the BSP manifest |
Required |
--app-id |
Defined in the <id> 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 |
The following example clones the "mtb-example-psoc6-low-power-analog-front-end" application with the desired name "LowPowerAnalog" configured for the CY8CKIT-062-WIFI-BT BSP into the specified working directory, C:/mtb_projects:
project-creator-cli --board-id CY8CKIT-062-WIFI-BT --app-id mtb-example-psoc6-low-power-analog-front-end --user-app-name LowPowerAnalog --target-dir "C:/mtb_projects"
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™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mtb_user_guide.pdf).
To work with a different supported kit later, use the Library Manager to choose the BSP for the supported kit. You can invoke the Library Manager GUI tool from the terminal using make library-manager command or use the Library Manager CLI tool "library-manager-cli" to change the BSP.
The "library-manager-cli" tool has the following arguments:
| Argument | Description | Required/optional |
|---|---|---|
--add-bsp-name |
Name of the BSP that should be added to the application | Required |
--set-active-bsp |
Name of the BSP that should be as active BSP for the application | Required |
--add-bsp-version |
Specify the version of the BSP that should be added to the application if you do not wish to use the latest from manifest | Optional |
--add-bsp-location |
Specify the location of the BSP (local/shared) if you prefer to add the BSP in a shared path | Optional |
Following example adds the CY8CPROTO-062-4343W BSP to the already created application and makes it the active BSP for the app:
library-manager-cli --project "C:/mtb_projects/MyHelloWorld" --add-bsp-name CY8CPROTO-062-4343W --add-bsp-version "latest-v4.X" --add-bsp-location "local"
library-manager-cli --project "C:/mtb_projects/MyHelloWorld" --set-active-bsp APP_CY8CPROTO-062-4343W
In third-party IDEs
Use one of the following options:
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Use the standalone Project Creator tool:
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Launch Project Creator from the Windows Start menu or from {ModusToolbox™ software install directory}/tools_{version}/project-creator/project-creator.exe.
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In the initial Choose Board Support Package screen, select the BSP, and click Next.
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In the Select Application screen, select the appropriate IDE from the Target IDE drop-down menu.
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Click Create and follow the instructions printed in the bottom pane to import or open the exported project in the respective IDE.
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Use command-line interface (CLI):
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Follow the instructions from the In command-line interface (CLI) section to create the application.
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Export the application to a supported IDE using the
make <ide>command. -
Follow the instructions displayed in the terminal to create or import the application as an IDE project.
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For a list of supported IDEs and more details, see the "Exporting to IDEs" section of the ModusToolbox™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mtb_user_guide.pdf).
If using a PSoC™ 64 "Secure" MCU kit (like CY8CKIT-064B0S2-4343W), the PSoC™ 64 device must be provisioned with keys and policies before being programmed. Follow the instructions in the "Secure Boot" SDK user guide to provision the device. If the kit is already provisioned, copy-paste the keys and policy folder to the application folder.
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Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.
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Open a terminal program and select the KitProg3 COM port. Set the serial port parameters to 8N1 and 115200 baud.
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Program the board using one of the following:
Using Eclipse IDE for ModusToolbox™ software
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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).
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. Ensure that the average of input voltage is displayed on the UART terminal.
Figure 1. Terminal output on program startup
You can debug the example to step through the code. In the 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™ software user guide.
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.
In this example, the analog components (OpAmp and SAR ADC) are configured to operate when the system is in Deep Sleep mode to make this example consume extremely low power. The OpAmp is configured as a voltage follower and its output is connected to the SAR ADC.
In Deep Sleep mode, the CPU and the rest of the peripherals are turned OFF, the SAR ADC and OpAmp continue to scan the inputs and load the results into the FIFO. The scan is initiated by the timer configured to trigger the SAR ADC every 5 ms. The interrupt from the FIFO wakes up the CPU when the number of samples in the FIFO is equal to the preconfigured value. In this case, it is 40 samples. With a timer period of 5 ms, the CPU is woken up every 200 ms (40 x 5 ms).
When an interrupt from the FIFO wakes up the CPU, the DMA transfers the raw data in the FIFO to the local buffer. Every 200 samples, i.e., every 1 second, the data in the local buffer is converted to the millivolt-equivalent, averaged, and sent to the UART terminal.
All the hardware configuration described above is done using the device configurator. The configuration is saved in a custom design.modus file in the application. In the firmware, the hardware is accessed using the peripheral driver library (PDL) rather than the higher-level hardware abstraction library (HAL) because of advanced features such as Deep Sleep operation of the SAR ADCs (with the availability of the timer and the low-power oscillator), which are not available in other PSoC™ 6 MCU devices. This example uses the Deep Sleep operation of the SAR ADC.
Figure 2. Flowchart
Figure 3. Timing diagram and current calculation
The current consumed by the PSoC™ 6 MCU device can be measured on the kit at the appropriate header. See the kit user guide for details. The bench current measurement for different states of the firmware is shown in Table 1.
Table 1. Current measurement
| State | Average current |
|---|---|
| Analog resources configured but SAR ADC conversion not started. Device is put to System Deep Sleep mode. | 7.4 uA |
| Normal operation | 75 uA |
This code example uses a custom configuration defined in the design.modus file located in COMPONENT_CUSTOM_DESIGN_MODUS. There is a sub-folder for each board supported. The components used in this example are one SAR ADC, one CTBm, DMA, and Timer.
The analog components used in this example are SAR ADC(SAR0) and OpAmp(CTBM0) which are available under the Peripherals tab in the device configurator. Because the OpAmp is configured to operate in Deep Sleep mode, the Deep Sleep clock and low-power oscillator are also enabled. The timer is used as the trigger for SAR ADC and configured to operate at 200 Hz, so the SAR ADC is triggered every 5 ms. The analog reference block (AREF) is configured to enable all voltages and current generators in Deep Sleep mode.
Figure 4. Enabling analog components in device configurator
In programmable analog resources, the OpAmp reference current is configured to the lowest option of 100 nA. The Deep Sleep option is enabled for the OpAmp.
Figure 5. Enabling OpAmp Deep Sleep operation
The OpAmp is configured for low power and the connections are configured for unity gain configuration. It acts as an input buffer.
Figure 6. OpAmp voltage follower configuration
The OpAmp includes a charge pump to get rail-to-rail input. When the OpAmp configured for operation in System Deep Sleep mode, to get the rail-to-rail input, the pump clock source should be set to Deep Sleep clock.
Figure 7. OpAmp charge pump clock configuration
The input to the SAR ADC is configured to be the output of the OpAmp, and the clock source is set to the Deep Sleep clock. In this example, only one channel of the SAR ADC is used. The SAR ADC is configured as single-ended where the reference voltage VDDA gives the input range of 0V to VDDA and input sampling is set to unsigned. Therefore, the input voltage range is 0 V - 3.3 V. The FIFO is configured to hold 40 samples, exceeding which an interrupt is raised, which triggers a DMA transfer. This is configured with the EOS trigger output option.
Figure 8. SAR ADC configuration
The DMA is configured to transfer 40 samples to a local buffer on every FIFO interrupt from the SAR ADC.
Figure 9. DMA configuration
Table 2. Application resources
| Resource | Alias/object | Purpose |
|---|---|---|
| SAR (PDL) | SAR | SAR driver to measure sensor voltages |
| SYSANALOG (PDL) | PASS | SYSANALOG driver for AREF, timer and Deep Sleep clock configuration |
| CTB (PDL) | CTBM | OpAmp for input buffer |
| DMA (PDL) | DMA | Data transfer |
| UART (HAL) | cy_retarget_io_uart_obj | UART HAL object used by retarget-io for debug UART port |
| Resources | Links |
|---|---|
| Application notes | AN228571 – Getting started with PSoC™ 6 MCU on ModusToolbox™ software AN215656 – PSoC™ 6 MCU: Dual-CPU system design AN85951 – PSoC™ 4 and PSoC™ 6 MCU CAPSENSE™ design guide |
| Code examples | Using ModusToolbox™ software on GitHub Using PSoC™ Creator |
| Device documentation | PSoC™ 6 MCU datasheets PSoC™ 6 technical reference manuals |
| Development kits | Select your kits from the evaluation board finder page. |
| Libraries on GitHub | mtb-pdl-cat1 – PSoC™ 6 peripheral driver library (PDL) mtb-hal-cat1 – Hardware abstraction layer (HAL) library retarget-io – Utility library to retarget STDIO messages to a UART port |
| Middleware on GitHub | capsense – CAPSENSE™ library and documents psoc6-middleware – Links to all PSoC™ 6 MCU middleware |
| Tools | [Eclipse IDE for ModusToolbox™ software]https://www.infineon.com/modustoolbox) – ModusToolbox™ software is a collection of easy-to-use software and tools enabling rapid development with Infineon MCUs, covering applications from embedded sense and control to wireless and cloud-connected systems using AIROC™ Wi-Fi and Bluetooth® connectivity devices. |
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.
For PSoC™ 6 MCU devices, see How to design with PSoC™ 6 MCU - KBA223067 in the Infineon Developer community.
Document title: CE230700 - PSoC™ 6 MCU: Low-power analog front-end using OpAmp and SAR ADC
| Version | Description of change |
|---|---|
| 1.0.0 | New code example |
| 1.1.0 | Updated to support v2.X CY8CKIT-062S4 BSP |
| 2.0.0 | Major update to support ModusToolbox™ v3.0. This version is not backward compatible with previous versions of ModusToolbox™. Updated to support v4.X BSP |
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