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Posted by alexanderbaev on January 16, 2015

Dear friends. I have the following problem – my program ends in the HardFaultHandler. I use STM32F429i-discovery board. On the first place I took the demo project (CORTEXM4FSTM32F407ZG-SK). I substituted several files and managed to run the kernel. Then I changed something (I really do not remember what) – and the problem occurred. I tried to do everything from scratch – nothing changed. Then I took template project presented by ST and added I suppose all necessary files for FreeRTOS (again from the ST package). All the code works properly before vTaskStartScheduler(); (I just display test string on the lcd). I tried to use the code by Joseph Yiu and it helped me to determine the place in which the program goes to the HardFault. It is in the file – portcm4.c

portBASETYPE xPortStartScheduler( void ) { /* Make PendSV and SysTick the lowest priority interrupts. */ *(portNVICSYSPRI2) |= portNVICPENDSVPRI; *(portNVICSYSPRI2) |= portNVICSYSTICK_PRI;

/* Start the timer that generates the tick ISR.  Interrupts are disabled
here already. */

/* Initialise the critical nesting count ready for the first task. */
uxCriticalNesting = 0;

/* Ensure the VFP is enabled - it should be anyway. */

/* Lazy save always. */

/* Start the first task. */

/* Should not get here! */
return 0;


After stepping through return 0 – program goes to the HardFault. In the disassembly window returne 0 is represented by the following: MOVS R0, #0 POP {R1, PC}

The value in the register R1 (again thanks to Joseph Yiu program) which then is loaded to PC points to the empty region (B55F38B9) – if I determined correctly it is 512 MB Block 5 FMC.

What should I check next?

PS: Demo project of ST with FreeRTOS works great, but it has much more then I need, and when I tried to remove certain parts I finished with compilation problems. PPS. In the current project I had to add the following to the main.c module to pass the compilation: void EndIdleMonitor(void) { }

void StartIdleMonitor(void) { }

void vApplicationTickHook(void) { }

void vApplicationMallocFailedHook(void) { }

void vApplicationIdleHook(void) { }


Posted by rtel on January 16, 2015

You code should not return from the call to vPortStartFirstTask(); (the clue is on the next line, where the comment says "should not get here").

vPortStartFirstTask() calls SVC 0, and I am guessing your problem is related to not have an SVC handler installed.

Normally FreeRTOS uses vPortSVCHandler() as the SVC handler, which can be mapped to its CMSIS name using a #define as described on this page: http://www.freertos.org/FAQHelp.html

What is installed as the SVC handler? It might be an ST handler that needs to chain with the FreeRTOS handler, but I think you can just install the FreeRTOS handler outright.



Posted by alexanderbaev on January 16, 2015

Thank you for the quick respond. The problem was exactly as you explained. What I did: 1) I added #define vPortSVCHandler SVCHandler #define xPortPendSVHandler PendSVHandler #define xPortSysTickHandler SysTickHandler to the FreeRTOSConfig.h file 2) Commented PendSVHandler, SysTickHandler, and SVCHandler in the stm32f4xx_it.c file. Did I do right?


Posted by rtel on January 16, 2015

Provided none of the ST libraries are relying on those handlers then that is fine.


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