Electrical – Generic ST-Link V2 Not Resetting Target


I bought a generic ST Link online, hooked it up to my target correctly (using SWDIO, SWCLK, GND, and RST), and tried to Target => Connect in the STM32 ST-LINK Utility, and got an error connecting (Can not connect to target). I know that this works on my target board, because with using an STM32 Discovery kit as an SWD programmer works without an issue. I've read a handful of other question on the site, and this one convinced me to trying to manually engage the reset before an operation and I have gotten a response by doing that, but it's pretty much useless if that's what's required.

So what's the deal with these programmers? Do they have crappy reset drivers or what? Feels pretty much useless to me if a manual / externally-timed reset is required. Are there known workarounds, or should I just buy Discovery boards just to use them as programmers?

Best Answer

I had the same problem! If you take a look at the PCB you see the NRST signal is messed up, meaning it is not connected to PB0 of the stm32F103 MCU in the programmer - instead it is connected to the "other side"(interestingly to a totally mirrored position of the MCU).

What I have done:

Removed the resistor R18 which connects the NRST connector pin to the wrong pin on the MCU. Then with a simple resistor 10R-100R I connected to NRST connector pin to the PB0 of the MCU (number 18 of the QFP 48).

After all, it woks just fine, for Trace support the SWO pin should be wired too You have to follow: https://lujji.github.io/blog/stlink-clone-trace/