nRF52840 SDK16 - USB MSC Example - What is happenning when the external flash memory get full?

RE: nRF52840 SDK16 - USB MSC Example - What is happenning when the external flash memory get full?

ovrebekk — Thu, 21 Jan 2021 09:41:48 GMT

I'm happy I could help Nikos. Thanks for sharing the documentation reference, that makes it pretty clear 🙂

RE: nRF52840 SDK16 - USB MSC Example - What is happenning when the external flash memory get full?

Nikosant03 — Fri, 15 Jan 2021 12:44:57 GMT

Thank you for your effort ovrebekk,

Just for reference, I've just found that your procedure to check full disk also described here

RE: nRF52840 SDK16 - USB MSC Example - What is happenning when the external flash memory get full?

ovrebekk — Fri, 15 Jan 2021 12:07:24 GMT

Hi Nikos

I did some testing to see what would happen, and it seems you don't get an error, but you will see that you are not able to write more bytes into the file.

UINT buffer_length = 64;
UINT bytes_written;
ff_result = f_write(&file, data_write_buffer, buffer_length, &bytes_written);
if(bytes_written < buffer_length || ff_result != FR_OK)
{
    NRF_LOG_ERROR("File write error: bytes %i, result %i");
}

If the f_write function reports less bytes written than you ask for it means there is no more room for data on the drive.

Best regards
Torbjørn

RE: nRF52840 SDK16 - USB MSC Example - What is happenning when the external flash memory get full?

Nikosant03 — Thu, 14 Jan 2021 16:54:16 GMT

Hi ovrebekk and thank you for your responce,

[quote userid="2116" url="~/f/nordic-q-a/70444/nrf52840-sdk16---usb-msc-example---what-is-happenning-when-the-external-flash-memory-get-full/289276#289276"]At some point you will not be able to create any more to files, and the file interface will return an error. [/quote]

Do you know what error it will return? I have to handle this error

RE: nRF52840 SDK16 - USB MSC Example - What is happenning when the external flash memory get full?

ovrebekk — Thu, 14 Jan 2021 15:47:01 GMT

Hi Nick

1. The fatfs file system library used in the USB MSC example uses fat32, which has a file size limit of 4GB.

2. At some point you will not be able to create any more to files, and the file interface will return an error.

Best regards
Torbjørn