I am using OZONE(V2.56i) to debug FreeRTOS on a STM32F437, Compiler GCC (Atollic TrueStudio for STM32 Version: 9.0.0 )




Starting the Programm In the Ozone-Debugger and Pause it(== crtl+F5), i can see the complete List of all FreeRTOS Tasks
and by clicking the Task, i see the assoceated CallStack of the Task.
- OK


BUG:
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The CallStack of one Task disappeares compleatly after some time (Only a Null- Pointer is shown)

This happens exactly after the first use of any FLOAT in this Threat - and stays until the next restart of the System.

Changeing the Code to Integer-Aritmetic (Fixpoint-Integer/ Q31) helps to overcome the Problem - for some time.

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The critical Threat is my GUI-Thread.

I am using emWin. (ST-library version)

when opening a Window, that uses a Circle or ARC (In AA-Mode) the problem is back (- no CallStack shown in OZON ) for this thread (after pausing the thread).
- I suppose there are some trigonometric functions like SIN inside the Draw-Circle(==using floats)


By elininating the Circles, the OZONE works fine, and i have the CallStack.


==> I tried to switch emWin to Software-Floats, but i could not manage.


INFO:
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When using a Breakpoint in the Thread, the Call-Stack is correct shown - the effect only occurs, when pausing the System in the Ozone-Debugger.



I need the pause-functionality in Ozone with the Call-Stack, because the Thread hangs some times (Closed-Loop), and i do not know where --> (No Place to set the Breakpoint)




I would be nice, if i can debug the Threads in Ozone, when Hardware-Supportet Float aritmetic is enabled

During preparing an Example for You, i discovered, that it is the same in Atollic-Debugger.

--> seems to be a Problem with the FreeRTOS awareness of the J-Link, not a Problem of Ozone

Test-Constellation:
1) STM32F429I-DISCO, ST-Link changed to "J-Link On Board" with J-Link Reflash utility to enable FreeRTOS-Awareness
2) CubeMX Project generated Project with 2 aditional Tasks, one calling a Subroutine with a Float
3) Pressing Pause --> You will get the Pictures in the attachement: The CallStack of myTask02/StartTask02 is empty