Write operation using FileX and LevelX on NOR flash is getting very slow at random

[gmandal]

Hi,

I am using W25Q64JV NOR flash of size 8MB on ST STM32U5A9ZJ board. On the flash I have created a file system using LevelX and FileX. I have enabled fault tolerant option in FileX. I am writing 128bytes of data every 500ms to a file. Initially the write operation is taking around 70-80 ms, however after some time (after around 3000 writes) the write operation occasionally is taking around 3-4 seconds. This is after every few writes. Following is the fx_media_format parameters I have used                                

status = fx_media_format( &flashMedia,
                          fx_stm32_levelx_nor_driver,
                          reinterpret_cast<VOID *>(LX_NOR_OSPI_DRIVER_ID),
                          reinterpret_cast<UCHAR *>(mediaMemory), sizeof(mediaMemory),
                          "FLASH_DISK", 
                          1,                             // Number of FATs
                          32,                            // Directory Entries
                          0,                             // Hidden sectors
                          (0x800000 - 0x10000)/ 0x10000, // Total sectors minus one
                          512,                           // Sector size
                          8,                             // Sectors per cluster
                          1,                             // Heads 1 
);

Could anyone please  let me know what I might to improve the performance? My goal is to complete the write operation of 128 bytes under 100ms in any circumstances. Thanks in advance.

Goutam

---

Edited to apply source code formatting - please see How to insert source code for future reference.

[LCE]

> (after around 3000 writes)

Do you or LevelX / FileX take care of wear leveling?

If you're doing your tests a few times you easily reach > 100k writes, and most flash memories getting problems from then on.

So check the flash's datasheet!

[Ozone]

Probably the code erases flash sectors as needed, once a write access crosses over into the next sector.
This sector erase can take dozens or hundreds of milliseconds, and is temperature and wear-dependant.