problem with SD card, FREERTO, FATFS and SDIO, USB_OTG_FS >> mass_storage_device

[Embedded_Engineer]

I'm working on a project involving the integration of USB functionality for data transfer and data logging on an STM32F407VG microcontroller. The project's objectives include logging data files on an SD card and allowing users to download these files via USB from the SD card. Additionally, users should be able to copy files from their PC to the SD card via USB, all achieved through the STM32F407VG using the SDIO communication protocol.

Specific Questions: <<

USB_OTG_FS Configuration:
How do I configure USB_OTG_FS as a USB Device in STM32CubeMX or other development tools for the STM32F407VG microcontroller?
Are there specific settings or configurations to consider when setting up USB_OTG_FS for this project?

>> Integration with FatFS for SD Card: <<
What are the essential initialization and setup steps for using USB_OTG_FS as a USB Device alongside the FatFS library for SD card communication on the STM32F407VG?
Can you provide guidance on potential conflicts or issues that may arise during this integration, and how to mitigate them?

>> Sample Code and Project Examples: <<
Do you have any sample code snippets or project examples that demonstrate the integration of USB functionality and the use of the FatFS library on an STM32 microcontroller, specifically the STM32F407VG?
Could you recommend reference materials that provide insights into setting up and using these features together?

>>Data Transfer Management:<<
What best practices should I follow to efficiently manage data transfer between USB and the SD card to prevent conflicts, data loss, or data corruption?
Are there specific considerations to be mindful of when handling data transfer between USB and the SD card?

>>Alternative Data Transfer via UART: <<
If USB_OTG_FS implementation doesn't work as intended, I've attempted data transfer from an SD card to another STM32 microcontroller via UART but encountered issues with long data transmission. Can you provide guidance on improving UART data transfer for this project?
Why might I be experiencing data loss when using UART to send data between microcontrollers, and how can I address this issue?

>> Code References and Errors: <<
I've included two code sections related to my project. Are there any specific issues or potential improvements you can identify in these code segments?
Do you have any recommendations or insights regarding debugging or optimizing the code for this project?

For the first problem (Integration of USB_OTG_FS and FatFS for SD Card):

"What I Tried: I attempted to integrate USB functionality for data transfer and data logging on an STM32F407VG micro-controller using USB_OTG_FS and FatFS for SD card communication. I followed the configuration steps for the microcontroller and implemented functions for initialization, read, and write operations on the SD card.

What I Was Expecting: I was expecting to successfully integrate USB_OTG_FS and FatFS to achieve the following:

Allow users to download data files from the SD card via USB.
Enable users to copy files from their PC to the SD card via USB.
Establish seamless communication between USB and SD card using the SDIO protocol.
I expected these functionalities to work cohesively without any issues."

For the second problem (Alternative Data Transfer via UART):

"What I Tried: As an alternative when my initial attempt with USB_OTG_FS didn't yield the expected results, I tried to transfer data from an SD card to another STM32 microcontroller using UART. I implemented code for encoding and transmitting metadata and data between the microcontrollers.

What I Was Expecting: My expectations for this alternative approach were as follows:

Successful transmission of data from one microcontroller to another using UART.
The ability to receive the transmitted data intact on the receiving end.
Logging the received data onto an SD card in the second microcontroller.
However, I encountered issues with long data transmissions and data loss, which were not aligned with my expectations."