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

[hmolesworth]

The default SPI settings use standard drive for the SCK and MOSI pins; it's perhaps worth checking whether they simply need to be set to high drive (typically required only at higher clock frequencies). Offhand I don't know whether the FATFS example already does that, but most examples do not. Here's an example, must be set after SPI initialise (or change within SPI init):

    nrf_gpio_cfg(SCK_PIN,
                 NRF_GPIO_PIN_DIR_OUTPUT,
                 NRF_GPIO_PIN_INPUT_DISCONNECT,
                 NRF_GPIO_PIN_NOPULL,
                 NRF_GPIO_PIN_H0H1,       // Require High Drive low/high level
                 NRF_GPIO_PIN_NOSENSE);

[Goose]

Did it require external pull-up resistors?