How to disable the ST-LINK from STM32MP157-DK1?

[JMart.13]

Hi everyone, hope everything is OK.

We are trying to use the STM32MP157-DK1 board for a project, but we notices that the ST-LINK included in the board consumes current even if we are not using it. There is a way to disable the ST-LINK by software? or do we have to modify hardware? We are using the board with openSTLinux as the operating system built with the YOCTO project.

Thanks for your answers.

[PatrickF]

Hi,

populating SB18 with a 0 ohm will keep the embedded ST-Link in reset, thus reducing it's consumption to minimum . Other option could be to remove SB21. In both cases, there will be no way to debug nor use USB Virtual Comm port thru CN11.

No ways to disable it by SW.

Development boards are not power optimized, so, you might not reach best possible low power consumption due to design choice (e.g. board component supply directly on VDD, DDR3L with VTT terminations, etc...) and system components (such as STLINK, LED, pull-up, pull-down, etc...).

Maybe look at this post : https://community.st.com/s/question/0D53W00000lzCWVSA2/power-management-with-stm32mp15x-and-openampttyechowakeup-example

Regards.

[JMart.13]

Hi @PatrickF​ thanks for the answer.

previously we considered removing the D1 to power off completely the ST-LINK but we didn't want to modify the hardware. Removing D1 causes any problem? or is better to put a 0 ohm on SB18 or removing SB21.

Thanks.

[PatrickF]

0 ohm on SB18 has no side effects, but will not completely remove STLINK power consumption.

Removing D1 or SB21 might need to remove SB22 as the un-powered STLINK might drop the NRST to low level.

Btw, some non-tested options, if you are eager to do some tricky wiring.

It might be possible to connect SB18 to PWR_ON with a diode (K on PRW_ON side) to automatically maintain STLINK in reset during Standby mode (similar to SB18).

Another option might be to connect INH pin of U34 to PWR_ON du disable STLINK supply (similar to D1 or SB21).

But I repeat, this is not tested, some drawback might occur.

Note that as per license agreement, development board are not suitable for building a product (e.g. boards are not resalable and ST does not guarantee long term availability).

Unless you are just prototyping/evaluating, if you are not willing to build your own PCB, you could probably find more suitable modules on 3rd party vendors (e.g. partners, but not limited to).

Regards.