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"no device found" with external target on Nucleo-ST-Link

b.a.
Associate III

Hi,

I just wanted to debug my STM32L412 custom board using my Nucleo-F767 as ST-Link just as I did many times before.

But this time it won't work! Connecting to the board always yields an

Error in initializing ST-LINK device.
Reason: No device found on target.

Connecting to the Nucleo-board works just fine.

Connecting to the custom board worked fine this morning. I could connect to 3 different custom boards, but all of a sudden it stopped working. Same phenomena last Friday. It initially worked well, but after a short while, impossible to connect. Some of the boards, I have used the ST-Link with very often before for much debugging. So the schematic and layout is fine and it worked for many boards of that kind for many weeks/months.

The ST-Link-STM32F103 is getting slightly warm, you can just feel it. But I never paid attention, so that might be normal...

BOOT0 is grounded, nRESET is high and gets pulled low by ST-Link.

I see activity on SCLK and SDIO although the clock does not look very nice to me. But again, since all worked well before, I never checked the signals.

Attached are two "screenshots" from the scope.

Channel 1 = nRESET

Channel 2 = SDIO

Channel 3 = SCLK

01 is the whole "data packet" being transmitted, 02 is a close up to show the strange clock signal.

I also tried STM32CubeProgrammer - no connection possible there as well.

I tried updating ST-Link firmware, downgrading to another version, and back up... reinstall drivers, updating CubeProg from 2.4.0 to 2.5.0, nothing worked so far.

This is a bit frustrating since now I don't knw where to look further...

any ideas?

all help very welcome!

Cheers,

Bob

4 REPLIES 4
TDK
Guru

Try lowering the SWD clock speed.

If you feel a post has answered your question, please click "Accept as Solution".
b.a.
Associate III

went down as low as 5kHz => No STM32 target found :(

b.a.
Associate III

Still cannot connect ST-Link to my board, any more advice?

TDK
Guru

See if the programmer can connect to a known good board.

Measure those same signals with a known good connection and see if they look different.

Check power rail of your custom board.

Post schematic of your custom board and/or check it for proper decoupling caps, power, NRST and BOOT0 connections.

If you feel a post has answered your question, please click "Accept as Solution".