Supplying voltage on VBAT pin on STM32F469I-DISCO

NKieg.1 · ‎2021-03-19

Hi everyone, I am currently working on a project working on a STM32F469I-DISCO. I would like to be able to use the embedded RTC as well as the backup SRAM. I have seen on the schematic that the VBAT pin is tied up to the 3.3V. Is there a way to still supply voltage to the VBAT pin (through the 3.3V for exemple) ?

Thank you.

waclawek.jan · ‎2021-03-19

Looking at gerbers of rev.C, it appears that the VBAT track is on bottom, appears to be quite well accessible.

If this is a one-off and you have some skills with cutting/joining PCB tracks (i.e. the usual techniques used to fix botched prototypes which are otherwise OK), it could be cut and brought out to some suitable point.

JW

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waclawek.jan · ‎2021-03-19

Unfortunately, no.

The more dense DISCO boards are unfortunately not very well designed with respect to general usability. ST's strategy moved from DISCO boards as a vehicle for having joy through experimentation, towards Nuclei as barebone board, and Discos being shiny but single-purpose boards.

As I've said too many times, ST does not understand the reason of the STM32's success.

JW

NKieg.1 · ‎2021-03-19

That's too bad ... My company wanted to avoid designing our own board but it may be something to think about then ...

waclawek.jan · ‎2021-03-19

Looking at gerbers of rev.C, it appears that the VBAT track is on bottom, appears to be quite well accessible.

If this is a one-off and you have some skills with cutting/joining PCB tracks (i.e. the usual techniques used to fix botched prototypes which are otherwise OK), it could be cut and brought out to some suitable point.

JW

NKieg.1 · ‎2021-03-19

Thank you a lot for your input. Unfortunately, this would not be a one off as we plan to use this board for a project which will be commercialized

Peter BENSCH · ‎2021-03-19

The use in a commercial product is not permitted anyway, see the Evaluation Board Terms Of Use:

The Evaluation Board shall not be, in any case, directly or indirectly assembled as a part in any production of Yours as it is solely developed to serve evaluation and testing purposes and has no direct function and is not a finished product.

Regards

/Peter

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NKieg.1 · ‎2021-03-19

Ow, I wasn't aware of that ... Guess we will have to design our own board and then the VBAT will be accessible!

Peter BENSCH · ‎2021-03-19

No problem. It seldom happens that the Terms of Use are read. 😀

Good luck!

When your question is answered, please close this topic by choosing Select as Best for the favourite answer. This will help other users find that answer faster.

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.