Read/Write file into eMMC using Fatfs on STM32H750B-dk

[Prajyot1]

Hello,
I am working on a project using the STM32H750B-DK board with an eMMC storage device, interfaced via the SDMMC1 peripheral and the FatFs library for file operations. However, I am unable to read or write files to the eMMC.

I have implemented the drivers and example code from `~\STM32Cube_FW_H7_V1.12.1\Projects\STM32H745I-DISCO\Applications\FatFs\FatFs_Shared_Device` and `~\STM32Cube_FW_H7_V1.12.1\Drivers\BSP\STM32H750B-DK`, but we are still unable to create files or perform read/write operations on the eMMC (4GB).

I am sharing my project zip file. Any guidance on adjustments or in configuration can be a big help.
Thank You.

[Andrew Neil]

What tests/investigations/debugging have you done to find where/why it's failing ?

Does it build cleanly - ie, with no errors and no warnings?

[Prajyot1]

@Andrew Neil 
Yes , we have build the project without errors.

i have customize diskio.c for eMMC
Action: Modified diskio.c to interface with the STM32H750B-DK’s SDMMC peripheral using the HAL MMC driver.
In diskio.c , implemented the required functions (disk_initialize, disk_status, disk_read, disk_write, disk_ioctl) to call HAL functions from stm32h7xx_hal_mmc.c.

while  debugging:

fres = f_mkfs("", FM_ANY, 0, workBuffer, sizeof(workBuffer));
 if (fres != FR_OK) {
    printf("f_mkfs failed: %d\n", fres);
    }

 i got fres = FR_DISK_ERR.

[Andrew Neil]

---

@Prajyot1 wrote:

 i got fres = FR_DISK_ERR.

---

So have you looked-up what that error code means?

Have you stepped into f_mks() to see where & why it fails?

[Prajyot1]

yes, i stepped int f_mks()  , got to know that
if (disk_write(pdrv, buf, b_vol, 1) != RES_OK) return FR_DISK_ERR; /* Write it to the VBR sector */
returning FR_DISK_ERR. function in diskio.c are not properly initialize causing failure. In that i need help..

[Prajyot1 · Accepted solution]

UPDATE:
i was able to create files or perform read/write operations on the eMMC (4GB) using `~\STM32Cube_FW_H7_V1.12.1\Projects\STM32H745I-DISCO\Applications\FatFs\FatFs_Shared_Device` and `~\STM32Cube_FW_H7_V1.12.1\Drivers\BSP\STM32H750B-DK`. the low level i/o implementation was wrong.

[Andrew Neil]

Great.

If that's resolved your issue, then please mark that post as the solution.

See: https://community.st.com/t5/community-guidelines/help-others-to-solve-their-issues/ta-p/575256

[Andrew Neil]

@Prajyot1 Thanks for marking the solution.

Your new question has been split to a new thread: STM32H750B-dk: access eMMC through USB OTG.

Please keep to one question per thread.