VDD12DSI pins in STM32H747BIT6

ikessimoPerdigo · ‎2025-03-24

Hello everyone,

I am working on a system based on the STM32H747BIT6 MCU and do not plan to use the DSI interface. I have searched through various forums but still have some doubts about the proper power pin configuration when DSI is not in use. Here is what I have so far:

VSSDSI: Connected to GND
VCAPDSI: Connected to VDD12DSI (capacitor not required)
VDD12DSI: Uncertain about the correct connection. I would like to avoid using an LDO to step down from 3.3V to 1.2V

Does anyone have experience with this setup or any recommendations on the best approach for VDD12DSI?

Thanks in advance.

mƎALLEm · ‎2025-03-24

Hello,

The same configuration as for STM32F777:

No need for external regulator. You need just to connect VDD12DSI to VCAPDSI.

Hope that answers your question.

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mƎALLEm · ‎2025-03-24

Hello,

The same configuration as for STM32F777:

No need for external regulator. You need just to connect VDD12DSI to VCAPDSI.

Hope that answers your question.

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.

TDK · ‎2025-03-24

Please see answers in this thread:

Solved: Can DSI pins on STM32H747 be left unconnected if n... - STMicroelectronics Community

If you feel a post has answered your question, please click "Accept as Solution".

ikessimoPerdigo · ‎2025-03-24

Thank you for your answers!

splee99 · ‎2025-05-17

Hi,

I'm still confused about the details. The reference manual says to connect VDDDSI to the global VDD. Then after connecting VDD12DSI and VCAPDSI, should I connect those to VDD global? That sounds little weird to connect the (1.2V?) to my global 3.3V VDD.

TDK · ‎2025-05-18

No, you should not connect VDD12DSI and VDD. Why would you? They are clearly disconnected in the figure and there is no text instructing you to connect them.

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splee99 · ‎2025-05-24

Hi,

Thanks for the clarification. Then I have a follow up question. I'm using STM32H757 with LTDC enabled to drive the TFT LCD in parallel interface. I also use the touchGFX package for the touch screen. The configuration tool automatically enabled the DSIHOST. I'm not sure what happens here. I'm using parallel interface for LCD and I still need the DSI?