Using Nucleo 144 as debugger/programmer for another board

[bramble]

Hi,

I read (here) that it's possible to use a Nucelo board's in-built ST-Link Vn debugger to program/debug a custom STM32 board. However, I have a doubt about this.

Please can anyone tell me whether such an approach is possible? I have available two Nucleo's: STM32F429 and STM32H755, and if either can be used to debug my custom H755 board that would be very good.

Advice about how to connect boards would be much appreciated.

Purchasing a debugger is obviously an option, but I don't like spending money.

Thanks

[Mike_ST]

Hello,

Please check the User Manual of the Nucleo-F429:

UM1974 

section 6.3.4

[bramble · Accepted solution]

Hi @Mike_ST ,

Ah, fantastic. I feel silly for not having checked the RM first, I should have learnt to always check there.

Anyway, many thanks for your very speedy response - this is definitely a nice feature to have available.

[Andrew Neil]

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@bramble wrote:

I read (here) that it's possible to use a Nucelo board's in-built ST-Link Vn debugger to program/debug a custom STM32 board. However, I have a doubt about this.

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This is true of the Nucleo-64 &-144 boards which have the break-off ST-Link section.

But it seems that some newer ones don't have this - and don't make it easy to use the onboard ST-Link with external targets.

As @Mike_ST said, how to do it will be in the UM for those boards which support it.

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@bramble wrote:

I have available two Nucleo's: STM32F429 and STM32H755,

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The Nucleo-F429 does have the break-off ST-Link:

The Nucleo-H775 does not have it:

[Mike_ST]

Maybe it is not needed to break the PCB, removing the IDD jumper to disable the stm32 might be enough.

Never tried myself.

[Andrew Neil]

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@Mike_ST wrote:

removing the IDD jumper to disable the stm32 might be enough.

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But that still leaves the onboard target microcontroller connected to the NRST, SWD, etc lines ...

The thing that's lacking on these "new" Nucleos is the facility to disconnect the onboard target from the ST-Link.

Maybe holding the onboard target in reset would be sufficient?

There was a thread on this recently: as someone said there, it should be possible - but not easy.

In these cases, I think the price of a separate ST-Link becomes worthwhile...

[Andrew Neil]

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@Andrew Neil wrote:
someone said there, it should be possible - but not easy.

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So "possible but not easy" was the key search term!

It was said by @TDK here:

https://community.st.com/t5/stm32-mcus-boards-and-hardware/stm32h7-nucleo-144-boards-mb1364-for-programming-external-board/m-p/798277/highlight/true#M25557 

See the rest of the thread for a description of how to do it...