Fatfs example does not work with every sd card?

[Michal]

Hi, I am working on application where I need to store some bigger files. I chose to use sdcard, but I get weird behaviour. Some sd cards, this looks like totaly random ones are working and other are not with fatfs on nrf52. I was trying few cards with fatfs example from SDK and one was working while all other seems to hang up at disk_initialization:

 0> <info> app: FATFS example.
 0> <info> app: Initializing disk 0 (SDC)...
 0> <info> spi: Init
 0> <info> spi: Function: nrf_drv_spi_init, error code: NRF_SUCCESS.
 0> <info> spi: Transfer tx_len:1, rx_len:10.
 0> <info> spi: Function: spim_xfer, error code: NRF_SUCCESS.
 0> <info> spi: Transfer completed rx_len:10.
 0> <info> spi: Transfer tx_len:6, rx_len:15.
 0> <info> spi: Function: spim_xfer, error code: NRF_SUCCESS.
 0> <info> spi: Transfer completed rx_len:15.
 0> <info> spi: Transfer tx_len:6, rx_len:15.

I tried making changes as suggested here: https://devzone.nordicsemi.com/f/nordic-q-a/25951/sd-card-example-not-working-fine but it wont help. I can work with that few are not working but it looks like most of them is not working. Is there recommended sdcard size/type/manufacturer to be used with nrf52?

Regards,

Michał

[Martin Lesund]

Hi Michał,

Could you provide some more information (size/type/manufacturer)  about the the SD cards. 
Which one works and which one doesn't work?

What SDK version do you use on the nRF52 DK ?

Do you have any additional information that could be helpfull so it can be reproduced for someone else?

[Michal]

Hi Martin,

Is there any chance that in fatfs port there is used CMD1 from fatfs ? https://stackoverflow.com/questions/8080718/sdhc-microsd-card-and-spi-initialization - I found it might be a problem for SDHC cards when used too early.

[Jakub Rzeszutko]

Hi Michał,

What are your test results with Arduino? Just curious.

So far I did not have a problem with this library. If example "hangs" I gues you are ending in some wait loop in function DSTATUS disk_initialize(BYTE drv).  May you please verify that with a debugger?

[Michal]

For Arduino the same card was the only one working so possible it something with the shield that I am using, I will try to eliminate hardware problem.

I debugged code yesterday and it looks like it went through initilization returning BUSY but for some reason it didnt print all logs (not deferred mode) leaving me with wrong impression that it hangs. From debugging I noticed that in app_sdcard I got too many retries at sending ACMD41. Shouldnt that command be preceded with CMD55 ?

[Turbo J]

The low-level diskio_* functions know to send the CMD55 before all ACMD* commands, so CMD55 won't show up in logs unless one monitors SPI directly.

[Michal]

Thanks Turbo J, indeed in app_sdcard in lines 320-330 there is check for ACMD and prefix to every of these commands... Honestly that is a pitty I was hoping there is bug somewhere here.