Disabling/enabling SPI Pins for SD Card

[Cornel Brülisauer]

I want to save Power by disabling the SD Card. VCC of the card is already regulated with an external MOSFET switch and controlled by a pin of the nRF. The problem now is, that the SPI data lines still power the SD Card. Therefore, I want to disable them. Is this possible, without having to redo the initialisation process of the SD Card? By the initialisation process I mean the following:

	/**
* @brief  SDC block device definition
* */
NRF_BLOCK_DEV_SDC_DEFINE(
    m_block_dev_sdc,
    NRF_BLOCK_DEV_SDC_CONFIG(
            SDC_SECTOR_SIZE,
            APP_SDCARD_CONFIG(SDC_MOSI_PIN, SDC_MISO_PIN, SDC_SCK_PIN, SDC_CS_PIN)
     ),
     NFR_BLOCK_DEV_INFO_CONFIG("Nordic", "SDC", "1.00")
);
static diskio_blkdev_t drives[] = {
      DISKIO_BLOCKDEV_CONFIG(NRF_BLOCKDEV_BASE_ADDR(m_block_dev_sdc, block_dev), NULL)  };

diskio_blockdev_register(drives, ARRAY_SIZE(drives));

NRF_LOG_INFO("Initializing disk 0 (SDC)...\r\n");


for (uint32_t retries = 3; retries && disk_state; --retries)
{
      disk_state = disk_initialize(0);
}
if(disk_state)
{
     NRF_LOG_INFO("Disk initialization failed.\r\n");
     return false;
}

[Cornel Brülisauer]

It is also a mystery to me, why there is still a voltage at the vcc line. But still, I want to disconnect the pins, in order to save power anyhow. But maybe I have to look into my mosfet switch again... I am using the SPI peripheral (SDK 12.3). The disconnect works fine. But now I have problems with enabling it again. I enable the pins like this:

 NRF_SPI1->PSEL.SCK = SDC_SCK_PIN | 0x80000000;
	NRF_SPI1->PSEL.MISO = SDC_MISO_PIN | 0x80000000;
	NRF_SPI1->PSEL.MOSI = SDC_MOSI_PIN | 0x80000000;

Is that correct? If I then use the function:

   if (f_mount(&Fatfs,"/",1) != FR_OK)
  {
		NRF_LOG_INFO("Mount failed.\r\n");
		return;
  }

It gets stuck in the default_wait_func(void) function in the file diskio_blkdev.c and stays there forever. Am I doing something wrong when reconnecting the pin or do I need to initialize the card again (as shown in the first question)?

[Renato Silva]

Did you resolve this problem?

I have a problem in fatfs example (SDK14)

The serial show me the follow error.

<info> app: FATFS example.
<info> app: Initializing disk 0 (SDC)...
<info> app: Capacity: 59400 MB
<info> app: Mounting volume...
<info> app: Mount failed.

[Jørgen Holmefjord]

This is not related to this question, unless you cut VCC to the SD Card. Please post a new question where you described your issue and setup in details.