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Associate III
Mar 31, 2026 9:45 AM UTC
Solved

STM32F407 Breakpoint crossed-out

When i try to add breakpoint, there is a cross sign on breakpoint symbol. So even if the code works, breakpoint never works.

I try to add __asm("BKPT 0"); but it also did not work.

 

I am not sure what is the problem.

My CubeID version is: 

Version: 2.1.1

Build: 28236_20260312_0043 (UTC)

Andrew Neil
Andrew NeilBest answer
Super User
Mar 31, 2026 10:32 AM UTC

CubeIDE is built on Eclipse, so it's often useful to search the internet using "Eclipse" rather than "CubeIDE" as a keyword.

eg, googling "eclipse crossed-out breakpoint" found this - does that help?

 

(other internet search engines are available)

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.

8 replies

Andrew Neil
Super User
Mar 31, 2026 9:52 AM UTC

Are you trying to place a breakpoint where there is no actual code?

Please show a screenshot of what you're seeing.

 

Please give details of your board, and what debug probe you're using - see: How to write your question to maximize your chances to find a solution

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.
Associate III
Mar 31, 2026 9:55 AM UTC

break point.jpg

Andrew Neil
Super User
Mar 31, 2026 10:00 AM UTC

You didn't answer the other question:

Please give details of your board, and what debug probe you're using

 

Are you able to single-step that code?

Can you place breakpoints elsewhere?

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.
Associate III
Mar 31, 2026 10:08 AM UTC

My board is STM32F407 discovery. I connect my board with USB-cable. For UART, i use TTL converter. I did not do single-step. When UART gets data (LED_ON) command from hercules, with my setup program must stop. But LED becomes on but program did not stop at the line which is on screenshot. I did not use specific probe or any kind of tool. My setup is basic.

Andrew Neil
Super User
Mar 31, 2026 10:17 AM UTC

@tensaisakuragi06 wrote:

 I did not do single-step..


Please try it - does it work ?

Also please try setting breakpoints elsewhere - do they work ?

 


@tensaisakuragi06 wrote:

 I did not use specific probe or any kind of tool. 


The STM32F407 discovery board has a built-in ST-Link

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.
Associate III
Mar 31, 2026 10:20 AM UTC

Whenever i add breakpoint it displays a cross symbol on it. Videos on internet, other ppl breakpoints doesnt not have a cross symbol on it. I try step-by-step, putting different lines of codes, inside the uart interrupt, outside the interrupt, inside the main etc. Breakpoint is not active. I made search about it but can not solve it yet.

Andrew Neil
Andrew NeilBest answer
Super User
Mar 31, 2026 10:32 AM UTC

CubeIDE is built on Eclipse, so it's often useful to search the internet using "Eclipse" rather than "CubeIDE" as a keyword.

eg, googling "eclipse crossed-out breakpoint" found this - does that help?

 

(other internet search engines are available)

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.
Associate III
Mar 31, 2026 10:40 AM UTC

Thank you. I try to figure out for 1 day. On ..flow forum, they mention  a settting which is Run> Skip all Breakpoint. In my setting this is selected. But i am sure i did not select it.