PSoC™ 6 MCU: littlefs Filesystem

This example uses the Arm® Cortex®-M4 (CM4) CPU of PSoC™ 6 MCU to execute a littlefs filesystem task.

At device reset, the default Cortex-M0+ (CM0+) application enables the CM4 CPU and configures the CM0+ CPU to go to sleep. The CM4 CPU mounts the filesystem on the storage device, reads a 32-bit value from a file, increments the value, writes the value back to the file, and finally prints the value to the UART terminal. You will see the value incrementing after every reset. The storage device can be either an SD card or a QSPI NOR flash.

This example uses the mtb-littlefs middleware library that implements the littlefs-compatible block device drivers for different storage devices such as SD card and NOR flash.

Provide feedback on this code example.

Requirements

• ModusToolbox™ v3.1 or later (tested with v3.1)
• Board support package (BSP) minimum required version: 4.0.0
• Programming language: C
• Associated parts: All PSoC™ 6 MCU parts, AIROC™ CYW20819 Bluetooth® & Bluetooth® LE SoC, AIROC™ CYW43012 Wi-Fi & Bluetooth® combo chip, AIROC™ CYW4343W Wi-Fi & Bluetooth® combo chip, AIROC™ CYW4373 Wi-Fi & Bluetooth® combo chip, AIROC™ CYW43439 Wi-Fi & Bluetooth® combo chip

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™ 62S2 Wi-Fi Bluetooth® Prototyping Kit (CY8CPROTO-062S2-43439) – Default value of TARGET
• PSoC™ 6 Wi-Fi Bluetooth® Prototyping Kit (CY8CPROTO-062-4343W)
• PSoC™ 6 Wi-Fi Bluetooth® Pioneer Kit (CY8CKIT-062-WIFI-BT)
• PSoC™ 6 Bluetooth® LE Pioneer Kit (CY8CKIT-062-BLE)
• PSoC™ 62S1 Wi-Fi Bluetooth® Pioneer Kit (CYW9P62S1-43438EVB-01)
• PSoC™ 62S2 Wi-Fi Bluetooth® Pioneer Kit (CY8CKIT-062S2-43012)
• PSoC™ 62S3 Wi-Fi Bluetooth® Prototyping Kit (CY8CPROTO-062S3-4343W)
• PSoC™ 62S4 Pioneer Kit (CY8CKIT-062S4)
• PSoC™ 62S2 Evaluation Kit (CY8CEVAL-062S2, CY8CEVAL-062S2-LAI-4373M2, CY8CEVAL-062S2-LAI-43439M2, CY8CEVAL-062S2-MUR-43439M2, CY8CEVAL-062S2-MUR-4373EM2, CY8CEVAL-062S2-MUR-4373M2)

Hardware setup

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

Note: The PSoC™ 6 Bluetooth® LE Pioneer Kit (CY8CKIT-062-BLE) and the PSoC™ 6 Wi-Fi Bluetooth® Pioneer Kit (CY8CKIT-062-WIFI-BT) 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".

Software setup

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.

Using the code example

Create the project

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

Use Project Creator GUI

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-psoc6-filesystem-littlefs-freertos" application with the desired name "FilesystemLittlefs" configured for the CY8CPROTO-062S2-43439 BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id CY8CPROTO-062S2-43439 --app-id mtb-example-psoc6-filesystem-littlefs-freertos --user-app-name FilesystemLittlefs --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

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.

The CY8CKIT-062-WIFI-BT, CY8CKIT-062-BLE, CYW9P62S1-43438EVB-01, CY8CPROTO-062S3-4343W and CY8CKIT-062S4 kits does not support SD card as the storage device. By default, the kit is configured to work in the NOR flash as storage device (ensure that the STORAGE_DEVICE_SD_CARD macro in the main.c is set to 0).

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

2. Open a terminal program and select the KitProg3 COM port. Set the serial port parameters to 8N1 and 115200 baud.

3. 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
   

4. After programming, the application starts automatically. Confirm that "Littlefs File System on SD Card and QSPI NOR Flash" is displayed on the UART terminal. When the application is run for the first time, mounting the filesystem might result in error in which case the memory is formatted and then the filesystem is mounted.

   Figure 1. First time mounting of littlefs

   

5. Now, press the reset button on the kit and observe that the boot_count is incremented.

   Figure 2. Boot count incremented after reset

   

6. If you press the User button on the kit, the memory will be formatted and the boot_count will be reset. You can press the reset button to increment the boot_count again.

   Figure 3. Formatting on user button press

   

7. By default, the application uses the QSPI NOR flash as the storage device. To change the storage device to the SD card, set the value of the macro STORAGE_DEVICE_SD_CARD in main.c to 1 and then build the application and program the kit.

Debugging

You can debug the example to step through the code.

In Eclipse IDE

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

Add the below Note for relevant CEs only, like PSoC 6 MCU based. Remove this note for others.

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 other IDEs

Follow the instructions in your preferred IDE.

Design and implementation

Resources and settings

Table 1. Application resources

Resource	Alias/object	Purpose
UART (HAL)	cy_retarget_io_uart_obj	UART HAL object used by retarget-io for debug UART port
GPIO (HAL)	CYBSP_USER_BTN	User button
SDHC (HAL)	sdhc_obj	Communication with the SD card
QSPI (HAL)	qspi_obj	Communication with the QSPI NOR flash

This example uses the littlefs filesystem API to perform simple file open/read/write operations and to retain a 32-bit data in non-volatile storage devices such as SD card and NOR flash. This example relies on the mtb-littlefs library that implements the block device drivers for use with littlefs.

This example uses the NOR flash as storage device by default. You can change it to the SD card by setting the value of STORAGE_DEVICE_SD_CARD to 1 in main.c. In this example, CM4 runs a FreeRTOS task that does the following:

1. Mounts the filesystem. If mounting fails, formats the storage device and mounts again.
2. Opens a file, reads a 32-bit data, increments the value, writes the data into the file, and closes the file
3. Displays the incremented data on the UART terminal
4. Waits for user action
5. If the User button is pressed, formats the storage device

This example sets COMPONENTS=RTOS_AWARE in the Makefile so that the low-level drivers such as the SDHC HAL enables RTOS-related features. For example, SDHC HAL waits on a semaphore until a read transfer completes. This example also sets DEFINES=LFS_THREADSAFE to enable thread-safety in a multi-threaded environment.

Related resources

Resources	Links
Application notes	AN228571 – Getting started with PSoC™ 6 MCU on ModusToolbox™ AN215656 – PSoC™ 6 MCU: Dual-CPU system design AN221774 – Getting started with PSoC™ 6 MCU on PSoC™ Creator AN210781 – Getting Started with PSoC™ 6 MCU with Bluetooth® Low Energy connectivity on PSoC™ Creator
Code examples	Using ModusToolbox™ on GitHub
Device documentation	PSoC™ 6 MCU datasheets PSoC™ 6 technical reference manuals
Development kits	Select your kits from the Evaluation board finder.
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	littlefs – littlefs filesystem mtb-littlefs – Block device drivers for littlefs capsense – CAPSENSE™ library and documents psoc6-middleware – Links to all PSoC™ 6 MCU 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.

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.

For PSoC™ 6 MCU devices, see How to design with PSoC™ 6 MCU - KBA223067 in the Infineon Developer community.

Document history

Document title: CE232816 - PSoC™ 6 MCU: littlefs Filesystem

Version	Description of change
1.0.0	New code example
2.0.0	Major update to support ModusToolbox™ v3.0. This version is not backward compatible with previous versions of ModusToolbox™
2.1.0	Updated to support ModusToolbox™ v3.1 and added support for CY8CPROTO-062S2-43439, CY8CEVAL-062S2-MUR-4373M2, CY8CEVAL-062S2-MUR-4373EM2

All referenced product or service names and trademarks are the property of their respective owners.

The Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc., and any use of such marks by Infineon is under license.

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