ST-LINK V3 is not working

[MTURAN]

Hello,

I have two STLINK-V3 programming devices. But I can't program or debug. When I try to connect to my device with STM32CubeProgrammer, I get the errors "Unable to get core ID" and "No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication". Can you help?

[Tesla DeLorean]

Review your circuits and connections, this generally indicates a LACK OF VIABILITY

So consider POWER, common grounding, that the ST-LINK expect you to provide VTarget to match your chosen voltage. Check voltage observed at VCAP pins/capacitors. Check level of NRST. Check VDDA, analogue supplies required regardless of ADC/DAC usage.

If the H7 had worked, and has now stopped responding, make sure your LDO / SMPS / VOS setting in software match the hardware you have built. You will need to power cycle with BOOT0 pin HIGH until you can connect, and erase your broken firmware.

Present your context more completely

[MTURAN]

There is no problem with my circuit and connections. Because I can connect and program with STLINK-V2. I was able to program with STLINK-V3 before, but now I can't connect.

[tjaekel]

We have seen sometimes similar issue: all was working fine, flashed and running a new FW and suddenly not able to connect with debugger again.

Try to use a different "Mode", e.g. "Under reset" or "Power down". Connecting with mode set as "Power down" was working in our case. On some MCUs running a long time, we saw issues that the FW "was lost" (entire flash was empty, no idea why).

As  Tesla DeLorean has mentioned: debugger needs two signals: VDD - used to monitor (not providing power) the target voltage and a pin on debug header which goes to GND (often with 100R). These signals are used by the ST-Link debugger in order to realize if debugger is connected to a target board and what is the target voltage. If something is wrong on these signals, the ST-LINK will complain about not seeing the target. But these signals seem to be OK in your case (it was working, V2 works).

I assume, your FW flashed and running might affect the capability to let debugger connect (e.g. debug pins disabled, MCU goes into low power modes, ...). Try with changing the "Mode".

If all this fails still:
use the BOOT0 pin: change it to high so that the internal bootloader is activated. Now you you could to flash (not debug) the FW, e.g. via USB (or UART). Suggestion: keep a working (simple) MCU FW to flash it in BOOT1 mode and to recover the board.
Maybe, in this boot mode the ST-LINK will connect now.

My suggestion: if this happens and you can bring debugger alive again - check first (before flashing a new FW) what is the content of the internal flash memory: does it have lost also all the previous content? (curious to know if somebody else sees issue that the FW is ripped out and MCU can run "crazy")

[Tesla DeLorean]

Sorry, not completely familiar of your situation from the initial post.

Does the ST-LINK/V3 work properly elsewhere on different boards/computers, or have you broken/damaged it?