Segger EMBEDDED STUDIO debugger breaks at random lines

[Learner]

Hello

I am running this version of SES

SEGGER Embedded Studio for ARM

Release 5.34a  Build 2021011401.44914

Nordic Edition

Windows x64

When I run my program in Segger it keeps stopping at these two particular lines. I do not understand why it is breaking because there are no breakpoints set. I deleted all of them.

It seems as if there are two 'hidden' breakpoints at these two lines. The Breakpoints window shows none.

Can someone please help?

Kind regards

Mohamed

[Karl Ylvisaker]

Hello Mohamed,

Could you specify which two lines you are referring to?
Is it the NRF_BREAKPOINT_COND you are referring to?

Could you also make sure to have DEBUG defined in your preprocessor defines, like shown in the included image?

This will make the logger output a detailed error message whenever a non-NRF_SUCCESS error code is passed to an APP_ERROR_CHECK.

Best regards,
Karl

[Learner]

Hi Karl,

I am not sure what NRF_BREAKPOINT_COND is. But just before this problem started showing up I tried to set a data breakpoint breaking when a variable is set to a particular value. I thought it di not work because I could not see any breakpoint in the Breakpoints window in SES. Could it be that this data breakpoint is actually set but not showing up?

Kind regards

Mohamed Belaroussi

[Learner]

Good Morning Karl,

Thank you for your help.

Karl Ylvisaker said:

Data breakpoints have a certain latency so the program will stop a few instructions after the actual variable is updated.

I think I found that my program never stopped and I thought you also confirmed this in your previous message. So, putting extra dummy instructions will not help. 

Did you see you program stopping few instructions after the actual variable was updated?

Kind regards

Mohamed 

[Karl Ylvisaker]

Hello again, Mohamed

Thank you for your patience with this.

Learner said:

Did you see you program stopping few instructions after the actual variable was updated?

Yes, I see the program stopping a few instructions after the data breakpoint condition was met. You will need to make sure that the variable is a global one, so they have a fixed address instead of being on the stack.

I have included a simple demonstration of this made for the nRF52840 DK with the nRF Connect v1.6.1 toolchain. Place it in \v1.6.1\zephyr\samples\basic\ and see if it works.
Please run this and see if you see the breakpoint triggering when the tester_variable is equal to 5.

Best regards,
Karl

5126.blinky_databreakpoint.zip

[Learner]

Thank you Karl,

I don't have access to an nRF52840DK.

Will the example run on nRF52833DK?

Kind regards

Mohamed

[Karl Ylvisaker]

Yes, you should be able to run it just fine on a nRF52833 DK, just change the build target in the Open NCS SDK project prompt. Remember to select the Clean build directory option before opening.
It might be that the breakpoint is not already there for the nRF52833 DK build, but then you can add it yourself following my prior instructions. Just set the expression to be tester_value == 5 or similar, you should also use set it as a hardware breakpoint.
Let me know if you encounter any issues with it.

Best regards,
Karl

[Learner]

Thank you Karl.

Karl Ylvisaker said:

You will need to make sure that the variable is a global one, so they have a fixed address instead of being on the stack.

So, are you saying Data breakpoints work only on global variables?

Kind regards

Mohamed

[Karl Ylvisaker]

No, but for testing purposes you should make them global.
For the general case you will need the variable to have a fixed address in memory (which global variables do) so that it can be watched.

Best regards,
Karl