STM32G474 died after trying to use two boards in the same computer (Error: ST-LINK error (DEV_TARGET_NOT_HALTED) )

[Mailson97]

Hello, everyone. I was trying to connect two prototypes in my computer: one containing a STM32L475 (connected through a ST-LINK V2) and the other using a STM32G474 (connected through a ST-LINK V3). The STM32CubeIDE warns about multiple ST-LINK connections. I was trying to setup two different workspaces for both projects, when suddenly the STM32G474 died (one LED controlled by the MCU turned off and I wasn't able to communicate with the MCU anymore). I am getting this error:

It could have been a coincidence that this happened when I was trying to connect both MCUs. I was trying to fix this error, but wasn't successful. The BOOT0 pin is being used in other function, so the boot is being defined through the option bytes. The NRST is also floating, I don't know if I need to do something with this pin to recover the MCU. I also tried all the connections and reset modes on the STM32CubeProgrammer, but it didn't work.

[TDK]

If the board was working and then stopped working, it's probably a hardware issue, so I would start there.

Looks like the board is still getting 3.3V, that's good. Looks like computer finds the programmer just fine. Also good.

You say NRST is floating, is it not hooked up to the programmer? NRST should have a 0.1 uF cap on it, probably not the issue here. Can't do a hardware reset if that's not connected, but it should also not be necessary unless you are going into low power modes or reassigning the SWD pins.

Can you measure VCAP voltage?

Can you measure the power draw on the chip? Should be something like 5 mA while in reset. You can also feel the chip to see if it's getting very hot. Lots of current or very hot indicates damage.

Can you share the schematic? Might be other issues.

[Mailson97]

Hi @TDK, thanks for you answer and sorry for the delay responding. NRST wasn't attached to the programmer, only the NJTRST. I replaced the chip and as expected, it worked. Regarding the tests you recommended, I wasn't with the tools to do some of them, but I used a thermal camera to see if the temperature was rising too much and it was OK. In a new prototype version I added an external reset circuit connected to the NRST pin, so now I can reset it through a button. This HALT error happened once again in this new prototype (didn't know yet the reason), but with the button and trough the STM32CubeProgrammer I changed the connection and reset mode and holding the reset button during the initialization I could access the board and erase the whole memory, so It came back to life. The next time this happen I will try to observe probable causes.