inconsistent watchdog reset

[Roshan]

Hi all,

I am practicing the Secure boot using SBSFU using the stm32L476 development board. I have implemented a code for the SBSFU, but it is giving a warning

WARNING: A Reboot has been triggered by a Watchdog reset!

      INFO: Last execution detected error was: Watchdog error.

= [EXCPT] WATCHDOG RESET FAULT!

and I define the key for the 0x0000AAAAu, but it gets restarted inconsistently,

for example, as first it will restart in 10 cycles of execution and next it will restart in 100 executions and again in 20 cycles like that, is there any reason behind this. I am really new to the SBSFU.

Thanks.

[Roshan]

Hi @Jocelyn RICARD​ 

Thank you for your valuable time, I will do it. furthermore, I found out that I work in a noisy environment and that could also lead to this problem.

furthermore, I have a question, for the firmware update we are normally using the Blue push button to get open the YModem protocol, for that can't I use another pin, is it so how can I map it.

[Jocelyn RICARD]

Hi Roshan,

the triggering of update is 100% up to your implementation.

SBSFU is an example code that is supposed to be adapted to your constraints.

First, the update can be done either by application (in case of 2 image) or by the bootloader internal loader, or by a standalone loader (specific application launched by SBSFU).

If you want to use the loader embedded in SBSFU, you can trigger this by an GPIO or even "logically" from your application.

By logically, I mean use a way to communicate to SBSFU that on next reset it will switch to update mode.

This can be done for instance using a specific RAM or backup SRAM location that is filled with a magic by application.

At next reset SBSFU detects this magic value and starts the update.

Such mechanism is provided in the STM32WB example

Best regards

Jocelyn