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.
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.
## Documentation
## Getting Started
Documentation for this library can be found here: https://github.com/azure-rtos/levelx/releases/download/v6.0_rel/Azure_RTOS_LevelX_User_Guide.pdf
Azure RTOS LevelX as part of Azure RTOS has been integrated to the semiconductor's SDKs and development environment. You can develop using the tools of choice from [STMicroelectronics](https://www.st.com/content/st_com/en/campaigns/x-cube-azrtos-azure-rtos-stm32.html), [NXP](https://www.nxp.com/design/software/embedded-software/azure-rtos-for-nxp-microcontrollers:AZURE-RTOS), [Renesas](https://github.com/renesas/azure-rtos) and [Microchip](https://mu.microchip.com/get-started-simplifying-your-iot-design-with-azure-rtos).
# Understanding inter-component dependencies
See [Overview of Azure RTOS LevelX](https://learn.microsoft.com/azure/rtos/levelx/overview-levelx) for the high-level overview, and all documentation and APIs can be found in: [Azure RTOS LevelX documentation](https://learn.microsoft.com/azure/rtos/levelx/).
The main components of Azure RTOS are each provided in their own repository, but there are dependencies between them--shown in the following graph--that are important to understand when setting up your builds.
## 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 # Microsoft 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`.
## Component dependencies
The main components of Azure RTOS 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.
# Building and using the library
> You will have to take the dependency graph above into account when building anything other than ThreadX itself.
## Prerequisites
### Building and using the library
Install the following tools:
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 Azure RTOS components as explained in the [Getting Started](#getting-started) section.
* [CMake](https://cmake.org/download/) version 3.0 or later
* [GCC compilers for arm-none-eabi](https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads)
* [Ninja](https://ninja-build.org/)
1. Install the following tools:
## Cloning the repo
* [CMake](https://cmake.org/download/) version 3.0 or later
* [Arm GNU Toolchain for arm-none-eabi](https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads)
1. Build the [ThreadX library](https://github.com/azure-rtos/threadx#building-and-using-the-library) as the dependency.
## Building as a static library
1. Cloning the repo.
Each component of Azure RTOS comes with a composible 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 command `add_subdirectory()`.
While the typical usage pattern is to include threadx 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.
1. 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`](https://github.com/azure-rtos/levelx/blob/master/common/inc/lx_user_sample.h) as an example.
Each component of Azure RTOS 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()`.
NOTE: You will have to take the dependency graph above into account when building anything other than threadx itself.
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.
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.
$ cmake --build ./build
```
## Releases
## Professional support
Each official release (preview or GA) will be tagged to mark the commit and push it into the Github releases tab, e.g. `v6.0-rel`.
[Professional support plans](https://azure.microsoft.com/support/options/) are available from Microsoft. For community support and others, see the [Resources](#resources) section below.
## Directory layout
## Licensing
```
- cmake
- common
- inc
- src
- samples
```
License terms for using Azure RTOS are defined in the LICENSE.txt file of this repo. Please refer to this file for all definitive licensing information. No additional license fees are required for deploying Azure RTOS on hardware defined in the [LICENSED-HARDWARE.txt](./LICENSED-HARDWARE.txt) file. If you are using hardware not listed in the file or having licensing questions in general, please contact Microsoft directly at https://aka.ms/azrtos-license.
# Security
## Resources
The following are references to additional Azure RTOS resources:
- **Product introduction and white papers**: https://azure.com/rtos
You can also check [previous questions](https://stackoverflow.com/questions/tagged/azure-rtos+levelx) or ask new ones on StackOverflow using the `azure-rtos` and `levelx` tags.
## Security
Azure RTOS 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.
# Licensing
## Contribution
License terms for using Azure RTOS are defined in the LICENSE.txt file of this repo. Please refer to this file for all definitive licensing information. No additional license fees are required for deploying Azure RTOS on hardware defined in the LICENSED-HARDWARE.txt file. If you are using hardware not defined in the LICENSED-HARDWARE.txt file or have licensing questions in general, please contact Microsoft directly at https://azure-rtos.ms-iot-contact.com/
# Contribution, feedback, issues, and professional support
If you encounter any bugs, have suggestions for new features, or if you would like to become an active contributor to this project, please follow the instructions provided in the contribution guideline for the corresponding repo.
For basic support, click Issues in the command bar or post a question to [Stack Overflow](http://stackoverflow.com/questions/tagged/azure-rtos+threadx) using the `threadx` and `azure-rtos` tags.
Professional support plans (https://azure.microsoft.com/en-us/support/options/) are available from Microsoft.
# Additional Resources
The following are references to additional Azure RTOS and Azure IoT in general:
| | |
|---|---|
| Azure RTOS Documenation and Guides: | https://docs.microsoft.com/azure/rtos |
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Tiejun Zhou