Micro-SD on STM32H7A3: f_mount returns "FR_NO_FILESYSTEM"

[GS1]

I have a new project on an STM32H7A3 processor with a  microSDHC Card. We want to read/write files with FatFS.

In another project with STM32H7A3 we have SDHC Cards working perfectly.

Code is created with the latest release of CubeMX 6.5.0 and HAL V: 1.10.0.

In the new project we had to use microSD card for reduced space reasons. 

With the microSD the call to fmount returns "FR_NO_FILESYSTEM". But on the PC the card is readable and has one folder installed.

I stepped through the source code and fount that the "find_volume" routine returns FR_NO_FILESYSTEM due to "fmt=3" .

Currently we have no idea for a possible solution. The pins are working and pin connection is checked, data is sent/received on the MISO/MOSI lines.

Clockspeed was 25 MHz, reducing to 20 and 16.6 MHz did not solve the problem.

USE_SD_TRANSCEIVER = 0.

Has anybody an idea where to look at further?

Is there any futher switch necessary to specify "micro"SDHC cards instead of SDHC?

Thank you for any comments.

BR GS

[crackl1ng]

Hi

What kind of Micro SD-Card are you using? Do you have it formatted correctly? . Your error code usually means, that the sd-card cannot be initialized due to wrong formatting. Try formatting to FAT/FAT32. If you've got another Micro SD card, give it a try. Also try a non-HC one, if you have got one laying around.

Kind regards and good luck

[GS1]

Card is a brand new 32 GB SDHC SanDisk card, which I formatted with FAT32. The other card (16 GB SDHC) did not work either. I don't have a NON-HC in house.

Thank you for your suggestions anyway.

[Tesla DeLorean]

Most SDHC, SDXC in micro and full-size all behave materially the same. Use 512-byte block numbering unlike the sub-4GB cards of yore that used byte level addressing. All microSD cards should be rated to at least 50 MHz.

So using SDMMC (1-bit) or SPI ?

Validate your read/write implementation in DISKIO, if this doesn't retrieve data properly nothing built on top is going to work either.

On H7 be conscious of DMA and cache coherency issues/management.

Polled mode should be impervious to that, but slower.

I'd expect FATFS/SDMMC demo code to be in the Applications directories for the 7A3/7B3 DISCO/DK/EVAL boards. Should port, should be configurable for 1-bit mode.

[GS1 · Accepted solution]

Hi,

Now I got it to work: By disabling the call to SCB_EnableDCache.

With DCache is enabled and even activated chache handling before DMA access the SD card read/write routines don't work.

I am not an expert on the cache handling and therefore I leave it this way with deactivated DCache for now.

Thank you for your hints on these aspects!!! As always: Very much welcome!

BR GS

[Piranha]

> I am not an expert on the cache handling and therefore I leave it this way with deactivated DCache for now.

Here is an instruction on how to do it properly:

https://community.st.com/s/question/0D53W00000oXSzySAG/different-cache-behavior-between-stm32h7-and-stm32f7