Bootloader via CAN-bus for STM32H743
Bootloader - program of bootloader via CAN-bus without set/reset additional pins of microcontroller
UserProgExample - example of user program with specifics that should be implemented for bootloader compliance
Win_Canloader - windows program for loading user program ( in .bin format) to microcontroller via CAN-bus
This bootloader works only with BANK1 of Flash memory.
Sector0 (0x8000000) - program of bootloader. After reset microcontroller always jumps to this address.
Sector1 (0x8020000) - user config data that can be erased and written by user program.
Sector2 (0x8040000) - user program. Can occupy all remaining sectors in BANK1.
After start running, bootloader waits CAN-messages with determined ID for some delay (default 2 sec). This delay can be set in user config data (Sector1).
After delay bootloader gives control to user program.
By default, bootloader communicates with two CAN-IDs: 0x560 and 0x570. If there are several boards on same CAN-bus, each board should identificate itself by writing its board-id to user config data (Sector1). Bootloader reads board-id and adds this value to CAN-ID expecting for program loading. For example, board-id is 2, so bootloader will wait CAN-messages with CAN-ID 0x562 and 0x572.
Messages with CAN-ID 0x56x are command messages to bootloader.
Messages with CAN-ID 0x57x are messages with program text bytes.
Baudrate of CAN-bus: 500 kbps.
0x8020000 - (uint32) config header: 0x0123fedc
0x8020004 - (uint32) board-id: from 0 to 0xF
0x8020008 - (uint32) delay before jump from bootloader to user program.
Units - milliseconds.
User program should implement some specifics to be compliant with bootloader:
-
Assignation of
Vector Table Offset Registershould be done at the beginning of the user program. -
Change memory areas address in
STM32H743ZITX_FLASH.ld:
FLASH (rx) : ORIGIN = 0x08040000, LENGTH = 1792K
In Keil: Options for target -> Linker -> R/O Base: 0x08040000
- In STM32CubeIDE set checkbox for creating output binary file :
Project-> Properties -> C/C++ Build Settings -> Tool Settings ->
MCU Post build outputs -> Convert to binary file (-O binary)
- Implement features to change user config data.
This windows application is used to download user program to microcontroller.
It works and tested with sysWORKXX USB CAN module1 of SYS TEC electronic
Start CANLoader.exe
Input board-id number. Click button Connect while bootloader program running. Ping with 1 sec period of CAN-message 0x551 starts.
Click Open to select file in .bin format. Then click Update to download user program.