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ST-link V2 Connection error.

Associate II

How do I solve this error? "Error: No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication"

I use SWD. I made the cable for SWD communication. The cable is connecting ST-LINK V2 between board. 

Yesterday, well, was connected to STM32CubeProgrammer.

But today it wasn't connected suddenly.....

I did everything I could by exploring the STM32 community.

Changed ST-LINK V2, the cable, reset mode, etc......

I saw massage what "ST-LINK error (DEV_TARGET_CMD_ERR)" in hardware rest mode.

But I don't solve this error.

Please help me....

ST Employee

@CSand Well, that is a question of expectations, as well as understanding what STMicroelectronics intended with this. First of all, as can be read in the Terms of Use, all NUCLEO are purely evaluation boards and are not authorised for use in production systems (usually nobody reads this, but have a look at RESTRICTIONS AND WARNINGS). Since STMicroelectronics is no longer quite a newcomer, such legal clarifications are simply necessary.

But if you find the format of the NUCLEO-64, which is intended as the base board for X-NUCLEO and was historically the first to appear, too large and unwieldy, why don't you take a look at variants of the NUCLEO-32?

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Peter, You may missed some part of my post ...
We have Nucleo-G431 and F303, they are both Nucleo-32.

We are providing customized solutions for production check-points where quantities are small. We rearly  have 5 projects the same - is this called production?

A solution is to develope own PCB board but that is not efficient at these quatities. And there is the same risk - will ST keep these chips compatible for how long? 

So we are using existing solution that is used by many and just fits as best for our needs.

Anyways - you just seem to justify to me why ST cannot help us anymore... .



ST Employee

@CSand indeed I haven't actually read everything in the thread, but you haven't used a complete and unambiguous description either. There are in fact

So I had to choose a variant.

Regarding your quantities: I repeat the statement from the Terms of Use:

[...] The Evaluation Board shall not be, in any case, directly or indirectly assembled as a part in any production of Yours as it is solely developed to serve evaluation an d testing purposes and has no direct function and is not a finished product.
If the Evaluation Board is incorporated in an evaluation system, the evaluation system may be used by You solely for Your evaluation and testing purposes. Such evaluation system may not be offered for sale or lease or sold, leased or otherwise distributed for commercial purposes and must be accompanied by a conspicuous notice as follows: “This device is not, and may not be, offered for sale or lease, or sold or leased or otherwise distributed for commercial purposes”. [...]

Even if you only sell 5 units of such products/systems/whateveryoucallit, you are legally in breach of these Terms of Use. Whether this will be prosecuted is another question. As the saying goes: where there is no plaintiff, there is no judge.

Developing our own circuit board would certainly be the optimal solution. However, there is exactly zero risk for such small quantities:

  1. firstly, there is a rolling commitment for product longevity for the STM32, which checks every spring whether each individual family can be extended for a further 10 years, which has so far been the case with only one exception (STM32L1)
  2. secondly, you can still keep a packaging unit (1500 or 2400) in stock shortly before the end of these 10 years, which will last for a correspondingly long time

Have I now explained why ST can still help you?


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Hi Peter, thanks for clarifying all details.

But as you told, ST not producing Bluepills for years now, we would not interfier with your wornings and restrictions - right?

In any case after long internal discussion we found a local pcb supplier that can develop and deliver for us a "production" board using genuine STM32F103 and would be delivering these boards for initial evaluation quite soon. 

In the meantime they helped and populate for us some Bluepill pcb's with chips from ST so we can continue what we do.

Thanks and Regards,


@CSand In fact, the Blue Pills are not from ST, nor does ST have anything to do with them. Also, ST's recommendations were not taken into account during their development and, on top of that, counterfeit STM32F103s have been used for several years.
ST could care less about all this, but unfortunately misguided users keep coming to the community and complaining about problems with Blue Pills.

To come back to your question: correct, since ST has nothing to do with the Blue Pills, the restrictions of the ST tools do not apply and you can do whatever the manufacturer allows you to do with it.

Good luck!

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