Bug unable to fix as going to unknown function 0x00000978..

RE: Bug unable to fix as going to unknown function 0x00000978..

bjorn-spockeli — Tue, 27 Aug 2019 08:20:45 GMT

Hi Arpitha,

happy to hear that you found the cause of the issue.

Best regards

Bjørn

RE: Bug unable to fix as going to unknown function 0x00000978..

ARPITHA CHANDRASHEKAR — Mon, 19 Aug 2019 08:48:12 GMT

Hi ,

Issue seems to be resolved as it was nrf_delay was blocking call and hence was going to unknown function. we have replaced it with non blocking delay.

Regards

Arpitha M C

RE: Bug unable to fix as going to unknown function 0x00000978..

ARPITHA CHANDRASHEKAR — Wed, 14 Aug 2019 09:34:47 GMT

Hi sir,

I have added logging statements to the code. Not much help. Can I know how to use Hard Fault library ? I included iar file related to Hard Fault and Hard Fault Implementation.c. Wanted to know where this this function to be called to check cause of hard fault.

Regards

Arpitha M C

RE: Bug unable to fix as going to unknown function 0x00000978..

bjorn-spockeli — Wed, 14 Aug 2019 09:22:58 GMT

Then my only suggestion would be to add logging statments to your code and use the log output to narrow down the function calls/routines that might cause the issue.

Best regards

Bjørn

RE: Bug unable to fix as going to unknown function 0x00000978..

ARPITHA CHANDRASHEKAR — Wed, 14 Aug 2019 05:23:05 GMT

Hi Sir,

I opened debugging by disabling MemManage break point. I have opened break points window there Memmanage break point gets highlighted, but I am unable to find out further to know root case of this exception.

Regards

Arpitha M C

RE: Bug unable to fix as going to unknown function 0x00000978..

bjorn-spockeli — Tue, 13 Aug 2019 11:28:00 GMT

It could be that the program have entered the hardfault exception handler inside the MBR. It's normally forwarded to the main application, but will get trapped if breakpoint on hardfault is enabled in SES. Make sure you have this breakpoint disabled in the breakpoints view.

Breakpoints window. Start a debug session and use Ctrl+Alt+b to open view.

This should ensure that the hardfault exception is forwarded to the application. Then you try to use the HardFault handling library to determine the cause of the Hardfault.

RE: Bug unable to fix as going to unknown function 0x00000978..

ARPITHA CHANDRASHEKAR — Tue, 13 Aug 2019 09:49:39 GMT

Hi,

Unfortunately I am not able to find out from which function its entering this mem manager. I have attached snap of program. It hits break point at Mem manage. However, I am able to see from IAR where it is entering. But again, IAR keeps running unlike segger which goes to unknown function but when paused it would have hit Hard Fault handler. So, in this case how do I be able to debug?

Regards

Arpitha M C

RE: Bug unable to fix as going to unknown function 0x00000978..

bjorn-spockeli — Tue, 13 Aug 2019 08:18:43 GMT

According to the Cortex M4 Devices Generic User Guide, found here

A MemManage fault is an exception that occurs because of a memory protection related fault. The the fixed memory protection constraints determines this fault, for both instruction and data memory transactions. This fault is always used to abort instruction accesses to Execute Never (XN) memory regions.

So this means that your application is likely writing to a protected region. Are you able to indentify the last function call prior to entering the MemManage handler?

RE: Bug unable to fix as going to unknown function 0x00000978..

ARPITHA CHANDRASHEKAR — Tue, 13 Aug 2019 05:21:41 GMT

Hi ,

Soft device version number is s140, 6.1.0. Also, i can see break point is getting hit at MemManage, is this issue with memory management. How can i read more about break points to see issue of memory management.

Regards

Arpitha M C.

RE: Bug unable to fix as going to unknown function 0x00000978..

bjorn-spockeli — Thu, 08 Aug 2019 12:22:43 GMT

[quote userid="82382" url="~/f/nordic-q-a/50769/bug-unable-to-fix-as-going-to-unknown-function-0x00000978"]1. What is the difference between debug and release mode?[/quote]

The only difference between debug and release mode is that Release mode optimizes the code for size and adds the NDEBUG definition to the preprocessor definitions. Debug mode does not use any optimization and adds the following preprocessor definitions DEBUG and DEBUG_NRF

[quote userid="82382" url="~/f/nordic-q-a/50769/bug-unable-to-fix-as-going-to-unknown-function-0x00000978"]2. What is the difference between segger and IAR?[/quote]

There are many differences, but i guess the main one is that Segger Embedded Studio uses the GCC compiler, while IAR has its own compiler.

[quote userid="82382" url="~/f/nordic-q-a/50769/bug-unable-to-fix-as-going-to-unknown-function-0x00000978"]3. I am unable to see stack frame , list of functions how it landed up to this unknown function? How will I check from which function this issue is happening ? [/quote]

The address 0x00000978 is located in the MBR, which is distributed together with the SoftDevice, see the Memory resource map and usage, as a precompiled binary.

This means that there are no debug symbols and debug information for the debugger, you're just able to see the disassembly.

If you provide me with the SoftDevice version number, then I can check what code that is placed at 0x00000978 in the MBR.

Best regards

Bjørn