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Eclipse ThreadX LevelX

LevelX provides NAND and NOR flash wear leveling facilities to embedded applications. Since both NAND and NOR flash memory can only be erased a finite number of times, it’s critical to distribute the flash memory use evenly. This is typically called wear leveling and is the purpose behind LevelX. LevelX presents to the user an array of logical sectors that are mapped to physical flash memory inside of LevelX. Applications may use LevelX in conjunction with FileX or may read/write logical sectors directly. LevelX is designed for fault tolerance. Flash updates are performed in a multiple-step process that can be interrupted in each step. LevelX automatically recovers to the optimal state during the next operation.

Getting Started

LevelX as part of Eclipse ThreadX has been integrated to the semiconductor's SDKs and development environment. You can develop using the tools of choice from STMicroelectronics, NXP, Renesas and Microchip.

See Overview of Eclipse ThreadX LevelX for the high-level overview.

Repository Structure and Usage

Directory layout

.
├── cmake                   # CMakeList files for building the project
├── common                  # Core LevelX files
├── samples                 # Sample codes
├── LICENSE.txt             # License terms
├── LICENSE-HARDWARE.txt    # Licensed hardware from semiconductors
├── CONTRIBUTING.md         # Contribution guidance
└── SECURITY.md             # Repo security guidance

Branches & Releases

The master branch has the most recent code with all new features and bug fixes. It does not represent the latest General Availability (GA) release of the library. Each official release (preview or GA) will be tagged to mark the commit and push it into the Github releases tab, e.g. v6.2-rel.

When you see xx-xx-xxxx, 6.x or x.x in function header, this means the file is not officially released yet. They will be updated in the next release. See example below.

/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _tx_initialize_low_level                          Cortex-M23/GNU    */
/*                                                           6.x          */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Scott Larson, Microsoft Corporation                                 */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function is responsible for any low-level processor            */
/*    initialization, including setting up interrupt vectors, setting     */
/*    up a periodic timer interrupt source, saving the system stack       */
/*    pointer for use in ISR processing later, and finding the first      */
/*    available RAM memory address for tx_application_define.             */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    _tx_initialize_kernel_enter           ThreadX entry function        */
/*                                                                        */
/*  RELEASE HISTORY                                                       */
/*                                                                        */
/*    DATE              NAME                      DESCRIPTION             */
/*                                                                        */
/*  09-30-2020      Scott Larson            Initial Version 6.1           */
/*  xx-xx-xxxx      Scott Larson            Include tx_user.h,            */
/*                                            resulting in version 6.x    */
/*                                                                        */
/**************************************************************************/ 

Component dependencies

The main components of Eclipse ThreadX are each provided in their own repository, but there are dependencies between them, as shown in the following graph. This is important to understand when setting up your builds.

dependency graph

You will have to take the dependency graph above into account when building anything other than ThreadX itself.

Building and using the library

Instruction for building the LevelX as static library using Arm GNU Toolchain and CMake. If you are using toolchain and IDE from semiconductor, you might follow its own instructions to use Eclipse ThreadX components as explained in the Getting Started section.

  1. Install the following tools:

  2. Build the ThreadX library as the dependency.

  3. Cloning the repo.

    $ git clone --recursive https://github.com/eclipse-threadx/levelx.git
  4. Define the features and addons you need in lx_user.h and build together with the component source code. You can refer to lx_user_sample.h as an example.

  5. Building as a static library

    Each component of Eclipse ThreadX comes with a composable CMake-based build system that supports many different MCUs and host systems. Integrating any of these components into your device app code is as simple as adding a git submodule and then including it in your build using the CMake add_subdirectory().

    While the typical usage pattern is to include LevelX into your device code source tree to be built & linked with your code, you can compile this project as a standalone static library to confirm your build is set up correctly.

    An example of building the library for Cortex-M4:

    $ cmake -Bbuild -GNinja -DCMAKE_TOOLCHAIN_FILE=cmake/cortex_m4.cmake .
    
    $ cmake --build ./build

Licensing

License terms for using Eclipse ThreadX are defined in the LICENSE.txt file of this repo. Please refer to this file for all definitive licensing information for all content, incl. the history of this repo.

Resources

The following are references to additional Eclipse ThreadX resources:

You can also check previous questions or ask new ones on StackOverflow using the threadx and levelx tags.

Security

Eclipse ThreadX provides OEMs with components to secure communication and to create code and data isolation using underlying MCU/MPU hardware protection mechanisms. It is ultimately the responsibility of the device builder to ensure the device fully meets the evolving security requirements associated with its specific use case.

Contribution

Please follow the instructions provided in the CONTRIBUTING.md for the corresponding repository.