STM32G0B1 bootloader problem on USART3

[MVanb.1]

After running the first production boards we discovers that the software update doesn't always work. There is main MPU that updates the ST MCU with internal bootloader using USART3. With some boards the update doesn't work.

• option bits are set use bootsel0 ping
• update with USART3 doesn not work
• hardware change to USART1 done => the update works
• clear MCU flash with J-link + power cycle => the update works once!

[Rim LANDOLSI]

Hello @MVanb.1​ ,

At first, let me thank you for reporting this issue.

The STM32G0B1xx bootloader is activated by applying Pattern 11 and for USART3 you can only use PC10 and PC11 pins. I advise you to refer at this AN2606 "STM32 microcontroller system memory boot mode" .

I hope this help you!

Thank you,

Rim.

[waclawek.jan]

Check, if during attemt to enter the bootloader you don't have activity on any other bootloader-related pin.

JW