STM32F103RB Nucleo – Debug fails after programming (“Target is not responding” in ST-LINK GDB Server)

srinathr · ‎2026-04-19

Hello,

I am working with an STM32F103RB Nucleo board. I am able to successfully connect and program the device using ST-LINK, but I am facing an issue during debugging.

The code is downloaded successfully and verified, but when the debugger tries to run (after the 'cont' command), it fails with the following error:

Error in executing 'cont' command
Target is not responding
Failed to read all registers from target

Setup details:
- Board: NUCLEO-F103RB
- ST-LINK Firmware: V2J47M34
- STM32CubeProgrammer: v2.20.0
- Debug Interface: SWD
- Connection Mode: Under Reset
- Reset Mode: Hardware reset
- SWD Frequency: 125 kHz

Observations:
- Programming completes successfully
- Verification is successful
- Issue occurs only when starting execution/debugging

Things I would like help with:
1. What could cause the target to stop responding immediately after programming?
2. Could this be related to clock configuration or incorrect startup code?
3. Are there specific debug settings (reset mode, SWD frequency, etc.) I should modify?

ERROR: -

STMicroelectronics ST-LINK GDB server. Version 7.11.0

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

Waiting for debugger connection...

Debugger connected

Waiting for debugger connection...

Debugger connected

Waiting for debugger connection...

-------------------------------------------------------------------

STM32CubeProgrammer v2.20.0

-------------------------------------------------------------------

Log output file: C:\Users\SRINAT~1.WOR\AppData\Local\Temp\STM32CubeProgrammer_a29124.log

ST-LINK SN : 066DFF495786534867176025

ST-LINK FW : V2J47M34

Board : NUCLEO-F103RB

Voltage : 3.27V

SWD freq : 125 KHz

Connect mode: Under Reset

Reset mode : Hardware reset

Device ID : 0x410

Revision ID : Rev X

Device name : STM32F101/F102/F103 Medium-density

Flash size : 128 KBytes

Device type : MCU

Device CPU : Cortex-M3

BL Version : --

Opening and parsing file: ST-LINK_GDB_server_a29124.srec

Memory Programming ...

File : ST-LINK_GDB_server_a29124.srec

Size : 8.20 KB

Address : 0x08000000

Erasing memory corresponding to segment 0:

Erasing internal memory sectors [0 8]

Download in Progress:

File download complete

Time elapsed during download operation: 00:00:02.645

Verifying...

Time elapsed during verifying operation: 00:00:00.900

Download verified successfully

Error in executing 'cont' command ...

Target is not responding, retrying...

Failed to read all registers from target

Target is not responding, retrying...

Shutting down...

Target is not responding, retrying...

mƎALLEm · ‎2026-04-20

Hello,

Do you have any low power configuration in your program?

See also this post.

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.

srinathr · ‎2026-04-21

it's look like, the power configuration is not low.
and the other problem which I am facing is while I am trying to debug the code I can't.

Error: -

STMicroelectronics ST-LINK GDB server. Version 7.11.0

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

Waiting for debugger connection...

Debugger connected

Waiting for debugger connection...

Debugger connected

Waiting for debugger connection...

-------------------------------------------------------------------

STM32CubeProgrammer v2.20.0

-------------------------------------------------------------------

Log output file: C:\Users\SRINAT~1.WOR\AppData\Local\Temp\STM32CubeProgrammer_a26712.log

ST-LINK SN : 066DFF495786534867176025

ST-LINK FW : V2J47M34

Board : NUCLEO-F103RB

Voltage : 3.26V

SWD freq : 4000 KHz

Connect mode: Under Reset

Reset mode : Hardware reset

Device ID : 0x410

Revision ID : Rev X

Device name : STM32F101/F102/F103 Medium-density

Flash size : 128 KBytes

Device type : MCU

Device CPU : Cortex-M3

BL Version : --

Opening and parsing file: ST-LINK_GDB_server_a26712.srec

Memory Programming ...

File : ST-LINK_GDB_server_a26712.srec

Size : 9.55 KB

Address : 0x08000000

Erasing memory corresponding to segment 0:

Erasing internal memory sectors [0 9]

Download in Progress:

File download complete

Time elapsed during download operation: 00:00:00.782

Verifying...

Time elapsed during verifying operation: 00:00:00.087

Download verified successfully

Target is not responding, retrying...

GdbSession, Lost target connection, Exiting...

Shutting down...

Exit.

mƎALLEm · ‎2026-04-21

Hello;

Sorry I didn't understand your reply.

"but when the debugger tries to run"

You have issue with CubeIDE right?

Why are you showing CubeProgrammer screenshot?

When I asked if you are having low power config it was about your application. So if you have for example in your code you put the device in standby mode you will lose the connection. So there is no relation with CubeProgrammer here ..

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.