FATFS working on MXIC MX25R6435F but not on S25FS128S

[MichielSch]

Hello,

We have integrated the FATFS example as shown in the usbd_msc example project into our own firmware application. It works perfectly on the nRF52840dk and when we modify our own hardware with the MX25R6435F chip it also runs fine on our own hardware. Meaning I can mount the filesystem, list the filesystem contents, create files, read files and modify the files.

However when we try to run it on our hardware with S25FS128S (which is the flash chip we use in production) we can only (seemingly) write the filesystem and mount it. When we try to create new files they do seem to get written (the lower level qspi functions are being called) but the filesystem itself does not get updated.

We looked on the devzone and found these examples: https://devzone.nordicsemi.com/f/nordic-q-a/50534/qspi-block-device-issue-with-s25fs-flash-part  and https://devzone.nordicsemi.com/f/nordic-q-a/56928/qspi-32bit-addressing-mode but I was not able to get the FS to behave properly. I am however able to use the memory in both 24 and 32bit addressing mode and get similar behavior.

This are the flash_params we used: static const nrf_serial_flash_params_t m_sflash_params[] = {
    {    /*S25FS128S*/
        .read_id = { 0x01, 0x20, 0x18 },
        .capabilities = 0x00,
        .size = 16 * 1024 * 1024,
        .erase_size = 4 * 1024,
        .program_size = 256,
    }
};

The chip ID is being read just fine.

How can it be that i seem to be able to read and write the FS itself but I'm not able to add files, let alone modify them. We are running on sdk 15.2 with softdevice 140 btw. 

Looking forward to your reply,

Best regards,

Michiel

[MichielSch]

Hi,

I found another piece of information that might be interesting to consider.

On the website of the manufacturer of the flash I found (I could share the link if you deem this appropriate):

By default, the S25FS128S flash device comes with hybrid sectors (the first sector of 64KB divided into 9 sectors (8 sectors of 4KB and one 32KB sector).  All remaining sectors are uniform (64KB each).

When you use the Control Center application from the FX3 SDK, the internal programming utility (CyBootProgrammer.img) assumes uniform sector size for the flash device; this leads to corrupted data in the first sector, which is a hybrid sector.

To prevent this, configure the flash device to use uniform sectors of 64KB each by modifying the Configuration Register 3 (CR3NV) – see Figure 1.

Figure 1. Configuration Register 3 (CR3NV): Address = 0x00000004

     

To configure the flash with uniform 64KB sectors, write ‘1’ to CR3NV[3] and ‘0’ to CR3NV[1] using the  WRAR 71h command (write 0x08 into the CR3NV register). After updating this register, use the default Control Center application to load the firmware image to the flash.

Could it be that these so called "hybrid sectors" are confusing the file system implementation? I would assume the implementation expects uniform sectors? I am currently trying to modify the settings of the memory chip.

Best regards,

Michiel