SD card interfacing in 4-bit mode

[mosgaard2000]

Hi,

I been looking around at the different questions about SD card interfacing, but can't find the solution I am looking for.

I would like to use the nRF52840 to interface to a SD card. Right now it is connected with a 1-wire SPI and the FatFS interface and everything seems to be working. I would like to switch to 4-bit SDIO mode instead, but having trouble finding info about it. Does anybody has an implementation of the 4-bit SDIO - and is it possible to use the QSPI interface on the nRF52840 for this or does it need to be bit-banging?

Also has anybody tried to use the FatFS interface with the QSPI/SDIO interface - I would like to be able to use the File commands in the FatFS.

[ketiljo]

Using a SD card in 4 bit mode will require licensing from the SD card association so you will not find any open software that supports this.