1# Azure RTOS LevelX 2 3LevelX 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. 4 5## Getting Started 6 7Azure 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). 8 9See [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/). 10 11## Repository Structure and Usage 12 13### Directory layout 14 15 . 16 ├── cmake # CMakeList files for building the project 17 ├── common # Core LevelX files 18 ├── samples # Sample codes 19 ├── LICENSE.txt # License terms 20 ├── LICENSE-HARDWARE.txt # Licensed hardware from semiconductors 21 ├── CONTRIBUTING.md # Contribution guidance 22 └── SECURITY.md # Microsoft repo security guidance 23 24### Branches & Releases 25 26The 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`. 27 28> 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. 29``` 30/**************************************************************************/ 31/* */ 32/* FUNCTION RELEASE */ 33/* */ 34/* _tx_initialize_low_level Cortex-M23/GNU */ 35/* 6.x */ 36/* AUTHOR */ 37/* */ 38/* Scott Larson, Microsoft Corporation */ 39/* */ 40/* DESCRIPTION */ 41/* */ 42/* This function is responsible for any low-level processor */ 43/* initialization, including setting up interrupt vectors, setting */ 44/* up a periodic timer interrupt source, saving the system stack */ 45/* pointer for use in ISR processing later, and finding the first */ 46/* available RAM memory address for tx_application_define. */ 47/* */ 48/* INPUT */ 49/* */ 50/* None */ 51/* */ 52/* OUTPUT */ 53/* */ 54/* None */ 55/* */ 56/* CALLS */ 57/* */ 58/* None */ 59/* */ 60/* CALLED BY */ 61/* */ 62/* _tx_initialize_kernel_enter ThreadX entry function */ 63/* */ 64/* RELEASE HISTORY */ 65/* */ 66/* DATE NAME DESCRIPTION */ 67/* */ 68/* 09-30-2020 Scott Larson Initial Version 6.1 */ 69/* xx-xx-xxxx Scott Larson Include tx_user.h, */ 70/* resulting in version 6.x */ 71/* */ 72/**************************************************************************/ 73``` 74 75## Component dependencies 76 77The 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. 78 79 80 81> You will have to take the dependency graph above into account when building anything other than ThreadX itself. 82 83### Building and using the library 84 85Instruction 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. 86 871. Install the following tools: 88 89 * [CMake](https://cmake.org/download/) version 3.0 or later 90 * [Arm GNU Toolchain for arm-none-eabi](https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads) 91 * [Ninja](https://ninja-build.org/) 92 931. Build the [ThreadX library](https://github.com/azure-rtos/threadx#building-and-using-the-library) as the dependency. 94 951. Cloning the repo. 96 97 ```bash 98 $ git clone --recursive https://github.com/azure-rtos/levelx.git 99 ``` 100 1011. 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. 102 1031. Building as a static library 104 105 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()`. 106 107 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. 108 109 An example of building the library for Cortex-M4: 110 111 ```bash 112 $ cmake -Bbuild -GNinja -DCMAKE_TOOLCHAIN_FILE=cmake/cortex_m4.cmake . 113 114 $ cmake --build ./build 115 ``` 116 117## Professional support 118 119[Professional support plans](https://azure.microsoft.com/support/options/) are available from Microsoft. For community support and others, see the [Resources](#resources) section below. 120 121## Licensing 122 123License 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. 124 125## Resources 126 127The following are references to additional Azure RTOS resources: 128 129- **Product introduction and white papers**: https://azure.com/rtos 130- **General technical questions**: https://aka.ms/QnA/azure-rtos 131- **Product issues and bugs, or feature requests**: https://github.com/azure-rtos/levelx/issues 132- **Licensing and sales questions**: https://aka.ms/azrtos-license 133- **Product roadmap and support policy**: https://aka.ms/azrtos/lts 134- **Blogs and videos**: http://msiotblog.com and https://aka.ms/iotshow 135- **Azure RTOS TraceX Installer**: https://aka.ms/azrtos-tracex-installer 136 137You 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. 138 139## Security 140 141Azure 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. 142 143## Contribution 144 145Please follow the instructions provided in the [CONTRIBUTING.md](./CONTRIBUTING.md) for the corresponding repository. 146
