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.

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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