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.
Update: the 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:
Pipeline status:
Repository
├── docs
├── drivers
│ ├── CMSIS
│ └── STM32L4xx_HAL_Driver
├── lib
│ ├── fatfs
│ └── stm32-bootloader
└── projects
├── STM32L476-CustomHw
├── STM32L496-CustomHw
└── STM32L496-Discovery
The docs
folder contains the generated documentation of the bootloader source
code and other documentation-related static files.
The 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. Additionally, the lib
folder contains the FatFs
library as well.
The various demonstrations reside in the projects
folder. Each example project
contains an include
and 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.
This repository contains the following examples.
Microcontroller | Hardware | Project path |
---|---|---|
STM32L476VG | Custom | projects/STM32L476-CustomHw |
STM32L496VG | Custom | projects/STM32L496-CustomHw |
STM32L496AG | 32L496GDISCOVERY | projects/STM32L496-Discovery |
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_Init()
.Bootloader_Erase()
.Bootloader_FlashBegin()
.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.Bootloader_FlashEnd()
.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:
Important notes:
system_stm32xxxx.c
file 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 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 [1].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.
[1] PM0214, “STM32F3 Series, STM32F4 Series, STM32L4 Series and STM32L4+ Series Cortex®-M4 Programming Manual”, http://www.st.com/resource/en/programming_manual/dm00046982.pdf