Hello,
We are using STM32U375xx/85xx MCUs and want to implement firmware update over UART using another MCU (ESP32-S3) in out application.
The ESP32 will send the .bin firmware to the STM32 without using any ST utility (e.g., CubeProgrammer).
From the STM32 AN2606 bootloader document, I understand that normally BOOT0/BOOT1 pins must be set to enter System Memory.
Question 1 — Entering Bootloader via Software
We want to enter the system bootloader purely by software, without toggling hardware BOOT pins.
How can this be done on the STM32U3 series?
Question 2 — Flashing Over UART from ESP32
Could someone provide the correct sequence for flashing a .bin into STM32U375/85 using the UART bootloader protocol?
(ESP32 will send the commands directly — no STM32CubeProgrammer involved.)
Steps I am looking for:
entering bootloader
UART initialization
bootloader command sequence (GET, GETID, ERASE, WRITE, GO)
any STM32U3-specific notes
Thanks in advance for any guidance.
