MCO Clock issue in ST-link firmware V2.J37.M26

[zzolio]

I am experiencing a bug in the ST-Link FW V2.J37.M26

setup

Nucleo-F446RE power from E5V

it takes a long time to "boot" or start to execute code. some code will never start running. the problem goes away if the ST-Link is power from USB before E5V is turn on

I have captured the problem on the scope. The MCO clock from ST-Link stops for about 2sek when power from E5V.

Nucleo-F446RE power from E5V ST-Link FW V2.J37.M26

Blu E5V

Yellow T_NRST

Pink MCO

Nucleo-F446RE power from USB ST-Link FW V2.J37.M26

Blu E5V

Yellow T_NRST

Pink MCO

Nucleo-F446RE power from E5V ST-Link FW V2.J34.M25

Blu E5V

Yellow T_NRST

Pink MCO

Note the the time division is different

The following FW versions are bug free

V2.J33.M25

V2.J34.M25

V2.J35.M26

I am curious

Why have ST chosen to gennerat the clock from the ST-Link MCU?

Best regards

Martin

[Tesla DeLorean]

>>I am curious. Why have ST chosen to generate the clock from the ST-Link MCU?

To save a crystal in the design.

You can add one if you want, or equally chose to use the HSI source rather than the HSE

[RConf.1]

I have a Nucleo-F207ZG board and I am facing the same problem: if you power the board from E5V or VIN, MCO starts to oscillate after approx 2 seconds when NRST signal is already high. Because of this wrong start-up sequence, most of codes will never start to run. The only solution is to manually reset the board after 2 seconds from power-up.

This problem doesn't happen if you power the board from the USB connector of the ST-LINK.

In addition to the original post, also the following FW versions have this bug:

V2.37.27

V2.38.27

Please, let us know if you implement a solution in the future ST-LINK firmware releases.

Thanks.

Regards,

Riccardo

[ASevi.1]

Good day, do you know of any link to download the st-link with firmware V2.J34.M25 or V2.J35.M26? Greetings.

[Tesla DeLorean]

https://community.st.com/s/question/0D53W00001pIyDkSAK/good-day-do-you-know-of-any-link-to-download-the-stlink-with-firmware-v2j34m25-or-v2j35m26-either-of-the-2-they-are-not-available-on-the-official-page-greetings

[Jonny802]

Hi Tesla, if I choose to use the HSI source instead of HSE, will I avoid taking the clock from the ST-Link board? How should I do it? If I decide to remove the ST-link board by separating it from the F429 nucleo-144  board will I loose the clock signal?    Thank you very much.    Where can I learn this easily?