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M
matteverze
Associate III
December 19, 2024
Solved

stm32wb5mm-dk external 5V power supply

  • December 19, 2024
  • 1 reply
  • 1185 views

Hi, I developed an application using the stm32wb5mm-dk. Everything works until I try to use an external 5V power supply. In fact, I change the position of JP2 on position 7-8 (to select 5V EXT) and I soldered SB4. However, when I supply the board through CN8, LD2 is on, JP1 is at 3.3V but the application on the STM32WB seems not to being run. If I provide power also through the USB STLK, it seems to start running. Is there any other JP or SB to adjust for extenal 5V supply?

Thanks.

 

Best answer by matteverze

Yes, of course. I found a work around. Instead of using the yellow path, I follow the green one, which powers also the ST link. This works.

matteverze_0-1734615230507.png

It seems that if the STLINK is not powered, it push the reset down. This can be a board design issue. 

Thanks

1 reply

M
matteverzeAuthor
Associate III
December 19, 2024

I can add that I verify that the pin NRST goes down when the STLINK is not powered.

Andrew Neil
Andrew Neil
Super User
December 19, 2024
@matteverze wrote:

the pin NRST goes down when the STLINK is not powered.

So that will be holding your target in reset.

Presumably, there's a jumper or solder-bridge to disconnect that?

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
M
matteverzeAuthor
Associate III
December 19, 2024

Hi, from the schematic (https://www.st.com/resource/en/schematic_pack/mb1292-wb5mm-d01-schematic.pdf) NRST is only connected to the STLINK and to the reset push button. No other information is given. Maybe is the STLINK (which is not powered) that pulls down the reset. Seems very strange

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