FatFS f_write does not work

[Mohammad A]

Posted on September 09, 2017 at 00:21

Function f_write doesn't work correctly to write on SD card. Actually it calls a series of other function and one of them is HAL_SD_WriteBlocks which puts the mcu into

Default_Handler:

Infinite_Loop: b Infinite_Loop

This is the code I have used to write a test string into a file:

 FATFS fs;
 FIL file;
 uint8_t string[]='string';
 UINT counter;
 if(f_mount(&fs,SD_Path,1)==FR_OK){
 if(f_open(&file,'root_f1',FA_WRITE|FA_CREATE_ALWAYS)==FR_OK){
 f_write(&file,string,(UINT)sizeof(string),&counter);
 }
 }
 f_close(&file);
 f_mount(NULL,'0:',1);�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?

I have tried enabling and disabling every interrupts or DMA, changing sd clock, bus width. Does not make difference.

This is while reading from the SD Card works.

CubeMX ver: 4.0

CubeF7 ver: 1.7.0

MCU: STM32F746

#bug #stm32 #f

[Gabriele Caletti]

Posted on September 14, 2017 at 16:28

I agree, I'm not sure it's a HAL issue. What I'm saying is that with the new HAL, the SDIO/FatFS seem to be less stable than before. In my case, with the following 2 changes the writing to the SD card works fine:

• set the compiler optimization off, i.e. -O0
• at SD card initialization comment out the step to move to a 4-bit data bus, i.e. HAL_SD_ConfigWideBusOperation(&uSdHandle, SDIO_BUS_WIDE_4B)

In my opinion, those changes as well as the ones reported by other users should not impact the SD wrinting functionality. This is why I have a bad feeling about the robustness of the HAL/FatFS combination.

[Tesla DeLorean]

Posted on September 14, 2017 at 16:40

Consider if your stack is large enough for the structures you are allocating on it. Does it fault if it is a static auto/local variable? How big is the stack, and how much of it is being used.

Look specifically at what is faulting, the CPU is capable of generating a lot of useful information about how/why it ended up there, a while(1) loop isn't going to be very informative.

[Mohammad A · Accepted solution]

Posted on September 14, 2017 at 20:23

Merci !!! That was really helpful. I have placed FIL and FATFS outside of main function and as global and now it works!

Of course in my case, I had to place both of these declarations as global, not just FIL .