Bootloader startup time on STM32L4R

[Ben Freudberg]

This is mostly a post to help people who try to google this later since I couldn't find anything. If you look at AN2606 table 197, it lists the minimum startup time for the bootloader on a bunch of different STM32 microcontrollers. For some reason, just two MCUs have "NA" listed including the chip I'm currently working with - the STM32L4R. So if anyone is wondering, my testing has shown that it takes ~90ms from reset/powerup to when the chip will ACK the 0x7F message on USART.

I am curious though, does anyone know why no time is listed for these chips?

[Imen.D]

Hello @Ben Freudberg ,

Thank you for bringing this to our attention.

I will check that and comeback to you soon with update.

[Imen.D]

Hi @Ben Freudberg ,

After an internal cross-check with the Bootloader team, we confirm this is a missing.

An internal ticket number 190555 is submitted in order to fix this.

(PS: This internal ticket number 190555 is only for reference, not available outside of ST)

Thank you again for having reported the point.

[Imen.D]

Hello @Ben Freudberg ,

A new version of AN2606 is now available to add the minimum startup time for the bootloader for STM32L4P5xx /Q5xx - STM32L4Rxx/4Sxx.