Error: No STM32 target found!

[markpow]

I think it is the most popular topic among STM32 programmers who use ST-LINK V2 programming devices.

I have two devices: one is the Lora E5 MIni, and the second is the Lora E5Dev board. Both respond to the AT commands, so I expect they are healthy.

A few days ago, I could access these devices and see their memory. Today, I can't, and I don't know why.

I connected the programmer to the dev board as needed, and I can't connect to this device.

I tried to change settings as the other programmers suggested to achieve connection to such devices but without any success. Programming STM32 controllers using ST-LINK V2 is a kind of magic. It's a horror for me. I can't program my devices.

I upgraded firmware versions several times without any changes.

From the ST-LINK, it looks as expected, I think:

As I wrote above, changes of modes and reset modes gave no change.

So, what is wrong? ST-LINK answers on connection, but why it doesn't see devices connected to it?

[TDK]

It may be worth purchasing a genuine programmer if you want tools you can trust to work. Could be a bad connection on the programmer.

Should be able to connect if you don't modify SWDIO/SWCLK pin functions and the chip is running. Otherwise, starting the chip into bootloader mode will let you connect.

[Pavel A.]

Could it be that somebody else played with these boards? Coworkers or kids? A lightning or power spike, maybe?

If possible, get a new set of hardware. 

[markpow]

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@Pavel A. wrote:

Could it be that somebody else played with these boards? Coworkers or kids? A lightning or power spike, maybe?

If possible, get a new set of hardware. 

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No, no one of them. It's winter in my country now, so lighting isn't expected. 

Yes, I ordered a brand-new programmer from a trusted reseller.

[Tesla DeLorean]

We get thunder-snow in the winter where I am.

Also gets to be very low humity as water falls out of the air, and indoor furnace heat drys the air. Watch for ESD / static discharge issues.

I seem to recall WaveShare doing PCBA for ST, so conceivable they have an agreement/license for ST-LINK/V2

Generally speaking the error comes from a lack of viability in the Target, circuits not powered, and thus non-responsive, or the part has physically locked out debugging. Behaviour with BOOT0=HIGH might be instructive. Connectivity of NRST required for "Connect Under Reset" to be possible.

[markpow]

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@Tesla DeLorean wrote:

Watch for ESD / static discharge issues.

Yes, I think the same now. It could be a static discharge issue. I programmed the last device about two weeks ago, and probably after that, I had this case. Before this case, it worked perfectly. If I recall correctly, there was a warning on the box to avoid static discharge. But is difficult to work still connected to the ground.

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@Tesla DeLorean wrote:

Behaviour with BOOT0=HIGH might be instructive. Connectivity of NRST required for "Connect Under Reset" to be possible.

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VaweShare ST-LINK mini doesn't have an NRST pin. What is the BOOT0=HIGH in this programmer's context?

[markpow]

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@TDK wrote:

Should be able to connect if you don't modify SWDIO/SWCLK pin functions 

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Let me know how to modify the SWDIO/SWCLK pin functions. To be honest, I don't know how.

[Tesla DeLorean]

>>What is the BOOT0=HIGH in this programmer's context?

It's a general STM32 hardware thing, a boot pin, or button, causing the MCU to run a system loader out of ROM vs user code in FLASH, the former being more of a safe-harbour, the latter reconfiguring pins or interfering.