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Cant connect to STM32F103 (Can not connect to target - error)

JSchi.1
Associate

Hello, i just got myself a bare STM32F103VET6 and designed myself a PCB to just make all the pins easy to access on a Breadboard.

Now i just want to connect to the chip via the STLINK V2 (clone) and the STLINK Utility Software.

But every time i get an error that the STLINK Utility is not able to connect to the Chip.

14:04:17 : Can not connect to target!
                  Please select "Connect Under Reset" mode from Target->Settings menu and try again.
                  If you're trying to connect to a low frequency application , please select a lower SWD Frequency mode from Target->Settings menu.
14:04:20 : Internal command error

This is how i have connected the device:

STLINK V2 STM32

3.3V <---> VCC

GND <---> VSS

SWDIO <---> PIN72 (SWDIO)

SWCLK <---> PIN76 (SWCLK)

I tried pulling BOOT0 High and low, and kept it floating, none worked.

I used an Oscilloscope to check if there is signal getting to the pin (checked for broken cable). There is something happening, but the Oscilloscope i have right now is not good enough to see the actual Signal, just that there is a signal.

I tried resetting the chip with pulling the RST Pin low, and erasing the Memory via the STLINK Utility, same error.

I have a small capacitor between VSS and VCC.

I already tried a 2nd STM32 because i thought i might have damaged the chip while soldering. Still same problem.

I am really lost at this point and dont know where to look or what to try.

So i would be really thankfull for any kind of help or input.

2 REPLIES 2
oeliks
Senior

Show PCB and schematic. Try boot0 boot1 low 100k.

Vss+vssa, vdd+vdda. Reset pin - 10k high.

Connect all vdd a, and vss a.​

Reset pin to stlink and flash under reset.​

JSchi.1
Associate

It works!

The problem was that I did not connect VSSA and VDDA.

Now I can connect to the Chip and flash it even without pulling the bootpins low.

Needless to say i feel kinda dumb right now...

Thank you very much you really saved my day.