There seem to be a mismatch in the STM32H747 documentation: The 176 pin version should have an VDDDSI pin, but it's missing in the pin definition and in the pinout. Is it a typo?

[AHoll.2]

According to the STM32H747xI/G datasheet, the STM32H747IG has a VCAPDSI pin, but no VDDDSI pin at all.

I'm sure i get something wrong here, because without VDDDSI pin, the VCAPDSI pin would be a miraculous source of energy! ;)

But seriously: do i have to connect an external LDO to the VDD12DSI pins? Or does the DSI regulator get its energy from an undocumented internal power routing in the 176 pin version?

Thanks a lot in advance!

Al

BTW: the pins 158 and 159 are swapped in the pinout (STM32H747xI/G datasheet)!

[Imen.D]

Hello @AHoll.2​ and welcome to the Community :)

VCAPDSI  VDDDSI pin is internally connected to VDD. So, I advise you to use a capa.

I will raise this point internally to request adding a note in the doc.

VCAPDSI pin must be externally connected to VDD12DSI pin to supply the DSI PHY (no internal connection).

> BTW: the pins 158 and 159 are swapped in the pinout (STM32H747xI/G datasheet)!

 I confirm this typo, and I request the correction (Ticket 114066) in the coming releases of the STM32H747xI/G datasheet.

(Ticket 114066: This is an internal tracking number and is not accessible or usable by customers)

Thanks for your contribution.

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

Imen

[AHoll.2]

Hi Imen,

thank you for you nice response. The DSI regulator makes more sense to me now.

Just to clarify:

I guess, it's not the VCAPDSI pin that is internally directly connected to some VDD pin,

but to be precise, it's the non-external VDDDSI signal that is internally connected to some VDD pin, right?

That would explain, where the DSI regulator gets its energy from.

Please confirm.

Also, i guess, it's not sufficient just to put a decoupling capacitor to the VCAPDSI pin, as somewhat implied by your answer,

but i still will have to connect VCAPDSI to the VDD12DSI pins, in order for the whole thing to make sense, right?

Please confirm.

(or is there another non-documented internal connection here?)

Thanks a lot in advance! :)

Albert

[Imen.D · Accepted solution]

Yes, VDDDSI is internally connected to VDD. Not the VCAPDSI.

VCAPDSI pin must be externally connected to VDD12DSI pin to supply the DSI PHY (no internal connection).

Thanks

Imen

[AHoll.2]

How i'm happy. Thank you very much!

BR, Albert