Using app_sdcard & fatfs with FreeRTOS

[Steve]

Hello everyone!

I want to use the app_sdcard to read/write with fatfs on a uSD card in my app which is based on FreeRTOS. While i was implementing this library, i saw that it use the protothread library.

Can i use protothread along with FreeRTOS? Is there another way around? 

Thank you!

[bjorn-spockeli]

Hi Steve, 

according to http://dunkels.com/adam/pt/ it should be possible to use protothreads together with an OS. However, I have never tried to integrate protothread in a FreeRTOS project. My suggestion would be to try to add it and if you run into any issues then you can post the issue here for assistance/help.

Best regards

Bjørn

[Steve]

Hi bjorn-spockeli,

I have tried to initialize the SD card within the Task that'll be responsible to read/write to the card but i ran into some hardfault after the initialization was done. Moving the init before starting the scheduler remove the hardfault. 

Now, I get the log "Disk initialization failed." with disk_state=1. Is it because i'm using a microSDHC and not a microSD? (i read a post about app_sdcard not being able to initialize SDHC nor SDXC but i lost the link)

The fatfs exemple worked with a SD but not with a SDHC/XC.

I'm using the SDK 15.3.0

[bjorn-spockeli]

I found this: https://devzone.nordicsemi.com/f/nordic-q-a/34401/fatfs-example-does-not-work-with-every-sd-card. It seems that for some SD cars one has to set the GPIO pins used by the SPI to high drive. 

Best regards

Bjørn

[Steve]

Thank you so much!

I changed in the sdk_config the "NRF_SPI_DRV_MISO_PULLUP_CFG" to 3 (pullup) and it worked well but i didn't find the define for the MOSI configuration.

Now I need to make my app read/write within a task and not before the scheduler start.

[bjorn-spockeli]

I think the MOSI pin is configured using nrf_gpio_cfg_output() which set the following configuration

__STATIC_INLINE void nrf_gpio_cfg_output(uint32_t pin_number)
{
    nrf_gpio_cfg(
        pin_number,
        NRF_GPIO_PIN_DIR_OUTPUT,
        NRF_GPIO_PIN_INPUT_DISCONNECT,
        NRF_GPIO_PIN_NOPULL,
        NRF_GPIO_PIN_S0S1,
        NRF_GPIO_PIN_NOSENSE);
}

You can replace the nrf_gpio_cfg_output() function with nrf_gpio_cfg() to set a higher drive, pull config etc..