No device found on target. After some succesfull uploads

assjo · ‎2025-05-06

Hi,

I am working with a custom board with the STM32L431CCU6 mcu. The bord consist of the mcu and 2 i2c units and one SPI.

The board also has pin headers for BOOT0, SWDIO and SWCLK.

Sory for paint...

I am using the CubeIDE and a ST-LINK V2for programming the board and have successfully programed Blink on it. This was not problem free however since my coputer sometimes did not recognised the ST-LINK and sometimes failed to upload. Unfortuanatli I do not remember those errors in details.

After succesfully uploading a program for i2c communication I could not program the board any more. The error i receive from the IDE is:

STMicroelectronics ST-LINK GDB server. Version 7.9.0
Copyright (c) 2024, STMicroelectronics. All rights reserved.

Starting server with the following options:
        Persistent Mode            : Disabled
        Logging Level              : 1
        Listen Port Number         : 61234
        Status Refresh Delay       : 15s
        Verbose Mode               : Disabled
        SWD Debug                  : Enabled
        InitWhile                  : Enabled

Target no device found

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

After a while of plugging the link in and out and trying to press boot and desperatly trying whatever I could, I tried a second board. This was a new board with a new ship but same problem. I tried using the ST-LINK of a NUCLEO board, same problem. Different computer, same problem. Cube programmer, same problem(? different errormessage: Error: Unable to get core ID, Error: No STM32 target found!) I am all out of ideas and no other post seems to solve my problem. Any ideas?

Andrew Neil · ‎2025-05-06

First, is it a genuine ST-Link?

https://community.st.com/t5/stm32-mcus/how-to-recognize-a-genuine-st-link-v2-versus-a-cloned-one/ta-p/49471

Note that breadboards are notoriously prone to unreliable connections - which can certainly mess-up your debugger connection.

Rather than route NRST via a breadboard, let the ST-Link control it and use connect under hardware reset.

@assjo wrote:
my coputer sometimes did not recognised the ST-LINK

You mean the ST-Link didn't even appear in Device Manager (or equivalent).

That suggests a USB connection problem between the computer & the ST-Link.

On resolving debugger connection issues:

https://community.st.com/t5/stm32-mcus/how-to-solve-connection-errors-when-connecting-and-programming/tac-p/786977

https://community.st.com/t5/stm32-mcus/how-to-solve-debugger-connection-issues/ta-p/49693

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

View solution in original post

Andrew Neil · ‎2025-05-06