Formatting a SD-Card with the nRF52840

[Casper Kronborg Pedersen]

Hi DevZone,

Does anyone have any experience with performing a SD-Card format with the nRF52840. This is to avoid removing the SD-Card from the hardware when a format is required.

I have been looking through the FatFS example from the Nordic SDK version 15.3. Below is the local location on my PC:

C:\SDK\nRF5_SDK_15.3.0_59ac345\examples\peripheral\fatfs\pca10056\blank\ses

This example uses the FatFS from ChaN (2014) and I have found the format IOCTL command at this location:

C:\SDK\nRF5_SDK_15.3.0_59ac345\external\fatfs\src\diskio.h (Line 59)

It seems like the user has to define their own disk format function to be attached to this command as it is not included in the nRF block device driver IOCTL function:

C:\SDK\nRF5_SDK_15.3.0_59ac345\components\libraries\block_dev\sdc\nrf_block_dev_sdc.c (line 336)

Has anyone done this successfully?

Br. Casper

[Simonr]

Updates from a few colleagues:

When accessing the memory module on the nRF52840DK over QSPI should definitely let you format an SD card, regardless of what's in the memory.

You can also use the f_mkfs() function to format the drive. This function  is documented here.

Best regards,

Simon

[Casper Kronborg Pedersen]

Hi Simonr,

The SD-card is connected with normal SPI just like the example in SDK 15.3

Is it possible to format the SD-card regardless of what is in the memory with normal SPI? (MOSI, MISO, CLK, CS)

I will experiment with the f_mkfs function, thank you :)

Br. Casper

[Casper Kronborg Pedersen]

Hi Simonr,

The f_mkfs function works on an SD-Card with normal SPI, even when the card has not been mounted.

I am using the FAT32 filesystem and I selected that option for the f_mkfs function as well as letting the allocation unit be the default value (input a 0 to the function). 

Thank you for your answers they were very helpful.

Br. Casper