Released: May, 2017 | Updated: June, 2020
Customizable Bootloader for STM32 microcontrollers. This project includes demonstrations for various hardware how to perform in-application-programming of a firmware located on external SD card with FAT32 file system.
Each example uses the same bootloader library located in the
lib/stm32-bootloader folder. The examples are located in the
projects folder and they come with a separate, dedicated README file with description related to that specific implementation.
STM32L496-Discovery example supports compiling and building the project with the GNU Arm Embedded Toolchain (ARM GCC) out-of-the-box, in addition to IAR EWARM. Check out the project README for further information.
Please refer to https://akospasztor.github.io/stm32-bootloader for complete documentation of the bootloader library source code.
Read more, clone or fork the project at my GitHub repository:
Repository ├── docs ├── drivers │ ├── CMSIS │ └── STM32L4xx_HAL_Driver ├── lib │ ├── fatfs │ └── stm32-bootloader └── projects ├── STM32L476-CustomHw ├── STM32L496-CustomHw └── STM32L496-Discovery
docs folder contains the generated documentation of the bootloader source code and other documentation-related static files.
drivers folder contains the CMSIS (Cortex Microcontroller Software Interface Standard) as well as the HAL (Hardware Abstraction Layer) drivers from ST.
The bootloader source code and corresponding header file can be found in
lib/stm32-bootloader folder of the repository. Additionally, the
lib folder contains the FatFs library as well.
The various demonstrations reside in the
projects folder. Each example project contains an
source folder where the header and source files are located respectively. The compiler and SDK-specific files are located in their respective subfolders. Furthermore, every example project has a dedicated README file explaining its functionality in detail.
The GitHub project repository contains the following examples. Each example has its own README file with detailed description located in the project repository.
The bootloader can be easily customized and tailored to the required hardware and environment, i.e. to perform firmware updates over various interfaces or even to implement over-the-air (OTA) updates if the hardware incorporates wireless communication modules. In order to perform successful in-application-programming, the following sequence has to be kept:
Bootloader_FlashNext()function. The programming procedure requires 8 bytes of data (double word) to be programmed at once into the flash. This function automatically increases the address where the data is being written.
The application image has to be in binary format. If the checksum verification is enabled, the binary must include the checksum value at the end of the image. When creating the application image, the checksum has to be calculated over the entire image (except the checksum area) with the following parameters:
system_stm32xxxx.cfile by default. This has to be either disabled (the bootloader can be configured to perform the vector table relocation before the jump) or manually set the the vector table offset register (VTOR) to the appropriate offset value which is the start address of the application space. For more information, please refer to .
The bootloader can be widely configured in the
bootloader.h file. The file includes detailed comments and descriptions related to the configurable parameters and definitions.
 PM0214, "STM32F3 Series, STM32F4 Series, STM32L4 Series and STM32L4+ Series Cortex®-M4 Programming Manual", http://www.st.com/resource/en/programming_manual/dm00046982.pdf