[SD Card] Sharing SPI pins sdcard

[gsalazar]

Hi,

I'm trying to use the nrf52832 with a sdcard application in SDK_13. I based my code on the example provided and managed to get the sd card working without any problems.

However I am now trying to get the another SPI slave working sharing the MOSI, MISO and CLK lines of the SD card without any success. I already manage the chip select pins manually before every call to the sdcard and the other spi slave however it still does not work.

I commented out the APP_ERROR_CHECK since the spi might already be initialized err_code = nrf_drv_spi_init(&m_spi, &spi_cfg, spi_handler, NULL); /*APP_ERROR_CHECK(err_code);*/

Does anyone have any idea on how to make it work? Is it possible using the SDK?

Here is an excerpt of the code which contains the main steps used:

nrf_gpio_cfg_output(cs_sdcard);
nrf_gpio_pin_write(cs_sdcard, HIGH);

nrf_gpio_cfg_output(cs_slave2);
nrf_gpio_pin_write(cs_slave2, HIGH);

/* Desired sector size and pins to configure */
m_block_dev_sdc.sdc_bdev_config.block_size = SDC_SECTOR_SIZE;
m_block_dev_sdc.sdc_bdev_config.sdc_config.mosi_pin = SPI_MOSI;
m_block_dev_sdc.sdc_bdev_config.sdc_config.miso_pin = SPI_MISO;
m_block_dev_sdc.sdc_bdev_config.sdc_config.sck_pin = SPI_SCLK;


/* Initialize SDcard block device work structure */
m_block_dev_sdc.p_work = &this->m_block_dev_sdc_work;
m_block_dev_sdc.block_dev.p_ops = (const nrf_block_dev_s::nrf_block_dev_ops_s*)&nrf_block_device_sdc_ops;

/* Initialize structure to registers a drive */
drive.config.p_block_device = &m_block_dev_sdc.block_dev;
drive.config.wait_func = NULL;
drive.last_result = NRF_BLOCK_DEV_RESULT_SUCCESS;
drive.state = STA_NOINIT;
drive.busy = false;

/* Registers a drive */
diskio_blockdev_register(&drive, NUMBER_OF_DRIVES);

/* Pointer to the file system object to be registered */
static FATFS filesys;

FRESULT mount_result;

nrf_gpio_pin_write(cs_sdcard, LOW);

/* Mounting volume */
mount_result = f_mount(&filesys, DEFAULT_DRIVE, MOUNT_IMMEDIATELY_OPT);

nrf_gpio_pin_write(cs_sdcard, HIGH);

nrf_gpio_pin_write(cs_sdcard, LOW);

/* Creating a partition */
f_fdisk(PHYSICAL_DRIVE, plist, &work);

/* Creating FAT32 file system */
create_fs_result = f_mkfs(DEFAULT_DRIVE, FM_FAT32, DEFAULT_ALLOCATION_UNIT_SIZE, work, sizeof(work));

nrf_gpio_pin_write(cs_sdcard, HIGH);

nrf_gpio_pin_write(cs_sdcard, LOW);

create_sign_result = f_open(&file1, FILE_SIGN_NAME, FA_CREATE_ALWAYS);

nrf_gpio_pin_write(cs_sdcard, HIGH);

/* This does not work */
nrf_gpio_pin_write(cs_slave2, LOW);

nrf_drv_spi_transfer(&spi_instance, register, size_register, NULL, 0);

nrf_gpio_pin_write(cs_slave2, HIGH);

Thanks

Edit: Added excerpt of code

[MartinBL]

If you don't uncomment APP_ERROR_CHECK() does the function return an error so you end up in an error handler? Here is a short guide on how to use return codes.

Have you tried to un-initialize the SPI driver with nrf_drv_spi_uninit() before you re-initialize it?

[gsalazar]

Yes, it returns it is already initialized and ends up in a error handler and restarts the microcontroller. If I initialize the SD card first and then the other slave the problem remains.

I have not tried un-initializing but I tried only initializing it once, via the SD card, to no avail.

[MartinBL]

nrf_drv_spi_init() will always return an error and not change your SPI configurations if you call it more than once in your application. That is unless you call nrf_drv_spi_uninit() between each call to nrf_drv_spi_init(). When you say "only initializing it once", does it mean that you only call nrf_drv_spi_init() once and it still returns an error?

[gsalazar]

If I only call it once it does not return error. However I cannot use the second slave that I have on the bus since the spi instance will have the spi_handler as defined in the app_sdcard.c and throw the APP_ERROR_CHECK(NRF_ERROR_INTERNAL); in line 979.

My main goal is being able to use 2 spi slaves in the same bus being a sd card on of them

[gsalazar]

Do you know if it is possible to use the SD card and another SPI slave using the same pins? Without using the spi_handler available in the app_sdcard.c