Hard Fault with FreeRTOS+FatFS on STM32

[Thomas Jespersen]

Posted on December 08, 2012 at 20:25

Hi all.

I have never really been the RTOS guy but I have decided to give it a try now, especially because of the need of a proper IP stack with Socket integration.

So I decided to get the FreeRTOS example with the lwIP stack provided by ST running on my STM32-E407 from Olimex, that contains an STM32F407ZGT6.

After successfully adding the FatFS library I was able to both get Ethernet and SD card working great.

But then I started making my LCD library and got that working, but when I tried my BMP writing routine, which repeatedly fetches 512 bytes (fills a buffer) from a file the application reads and displays two full buffers but then goes into a Hard Fault.

I have tried getting most information out of this Hard Fault exception as possible which can be seen below:

[Hard fault handler - all numbers in hex]

R0 = 20001158

R1 = 1eaf00b4

R2 = 80031a5

R3 = 80031a5

R12 = 20000cac

LR [R14] = a5a5a5a5  subroutine call return address

PC [R15] = fffffffd  program counter

PSR = 80078c2

BFAR = 1eaf00b4

CFSR = 8200

HFSR = 40000000

DFSR = 1

AFSR = 0

SCB_SHCSR = 400

I am using the pvPortMalloc(512) to get a pointer to the required 512 bytes buffer, but that didn't fix the problem.

You can download the CoIDE project (IDE for GCC compiler) and have a look for yourself: 

http://www.tkjelectronics.dk/uploads/TheBlastFootball_FreeRTOS_HardFault.zip

I really hope that someone can bring me some suggestions.

Best Regards

Thomas Jespersen

#freertos #fatfs #lwip #hardfault

[Thomas Jespersen]

Posted on December 08, 2012 at 22:19

I have found the solution to this problem, which is due to me being new in this RTOS field.

When creating the thread which executes the BMP LCD write function I didn't make the stack for this thread large enough to hold the buffer.

The stack was only set to 256 bytes, where the buffer itself takes 512!

By increasing the size to 1024 bytes the program works perfectly.

xTaskCreate(UserGUI, ''UserGUI'', 1024, NULL, GUI_TASK_PRIO, NULL);

Regards Thomas