SPI SD Card driver

Driver for reading and writing SD Cards using the SPI. More...

Detailed Description

Driver for reading and writing SD Cards using the SPI.

Files
file	sdcard_spi.h
	Public interface for the sdcard_spi driver.
file	sdcard_spi_internal.h
	Interface for issuing commands on sd-cards via SPI.
file	sdcard_spi_params.h
	Default parameters for sdcard_spi driver.

Data Structures
struct	cid_t
	CID register see section 5.2 in SD-Spec v5.00. More...
struct	csd_v1_t
	CSD register with csd structure version 1.0 see section 5.3.2 in SD-Spec v5.00. More...
struct	csd_v2_t
	CSD register with csd structure version 2.0 see section 5.3.3 in SD-Spec v5.00. More...
union	csd_t
	CSD register (see section 5.3 in SD-Spec v5.00) More...
struct	sd_status_t
	SD status register (see section 4.10.2 in SD-Spec v5.00) More...
struct	sdcard_spi_params_t
	sdcard_spi device params More...
struct	sdcard_spi_t
	Device descriptor for sdcard_spi. More...

Macros
#define	SD_HC_BLOCK_SIZE   (512)
	size of a single block on SDHC cards
#define	SDCARD_SPI_INIT_ERROR   (-1)
	returned on failed init
#define	SDCARD_SPI_OK   (0)
	returned on successful init
#define	SD_SIZE_OF_OID   2
	OID (OEM/application ID field in CID reg)
#define	SD_SIZE_OF_PNM   5
	PNM (product name field in CID reg)

Enumerations
enum	sd_version_t { SD_V2 , SD_V1 , MMC_V3 , SD_UNKNOWN }
	version type of SD-card More...
enum	sd_rw_response_t {   SD_RW_OK = 0 , SD_RW_NO_TOKEN , SD_RW_TIMEOUT , SD_RW_RX_TX_ERROR ,   SD_RW_WRITE_ERROR , SD_RW_CRC_MISMATCH , SD_RW_NOT_SUPPORTED }
	sdcard_spi r/w-operation return values More...

Functions
int	sdcard_spi_init (sdcard_spi_t *card, const sdcard_spi_params_t *params)
	Initializes the sd-card with the given parameters in sdcard_spi_t structure.
int	sdcard_spi_read_blocks (sdcard_spi_t *card, uint32_t blockaddr, void *data, uint16_t blocksize, uint16_t nblocks, sd_rw_response_t *state)
	Reads data blocks (usually multiples of 512 Bytes) from card to buffer.
int	sdcard_spi_write_blocks (sdcard_spi_t *card, uint32_t blockaddr, const void *data, uint16_t blocksize, uint16_t nblocks, sd_rw_response_t *state)
	Writes data blocks (usually multiples of 512 Bytes) from buffer to card.
uint64_t	sdcard_spi_get_capacity (sdcard_spi_t *card)
	Gets the capacity of the card.

Macro Definition Documentation

SD_HC_BLOCK_SIZE

#define SD_HC_BLOCK_SIZE   (512)

size of a single block on SDHC cards

Definition at line 33 of file sdcard_spi.h.

SD_SIZE_OF_OID

#define SD_SIZE_OF_OID   2

OID (OEM/application ID field in CID reg)

Definition at line 37 of file sdcard_spi.h.

SD_SIZE_OF_PNM

#define SD_SIZE_OF_PNM   5

PNM (product name field in CID reg)

Definition at line 38 of file sdcard_spi.h.

SDCARD_SPI_INIT_ERROR

#define SDCARD_SPI_INIT_ERROR   (-1)

returned on failed init

Definition at line 34 of file sdcard_spi.h.

SDCARD_SPI_OK

#define SDCARD_SPI_OK   (0)

returned on successful init

Definition at line 35 of file sdcard_spi.h.

Enumeration Type Documentation

sd_rw_response_t

enum sd_rw_response_t

sdcard_spi r/w-operation return values

Enumerator
SD_RW_OK	no error
SD_RW_NO_TOKEN	no token was received (on block read)
SD_RW_TIMEOUT	cmd timed out (not-busy-state wasn't entered)
SD_RW_RX_TX_ERROR	error while performing SPI read/write
SD_RW_WRITE_ERROR	data-packet response indicates error
SD_RW_CRC_MISMATCH	CRC-mismatch of received data.
SD_RW_NOT_SUPPORTED	operation not supported on used card

Definition at line 162 of file sdcard_spi.h.

sd_version_t

enum sd_version_t

version type of SD-card

Enumerator
SD_V2	SD version 2
SD_V1	SD version 1
MMC_V3	MMC version 3.
SD_UNKNOWN	SD-version unknown.

Definition at line 152 of file sdcard_spi.h.

Function Documentation

sdcard_spi_get_capacity()

uint64_t sdcard_spi_get_capacity

(

sdcard_spi_t *

card

)

Gets the capacity of the card.

Parameters

[in]

card

Initialized sd-card struct

Returns

capacity of the card in bytes

sdcard_spi_init()

int sdcard_spi_init	(	sdcard_spi_t *	card,
		const sdcard_spi_params_t *	params
	)

Initializes the sd-card with the given parameters in sdcard_spi_t structure.

The init procedure also takes care of initializing the spi peripheral to master mode and performing all necessary steps to set the sd-card to spi-mode. Reading the CID and CSD registers is also done within this routine and their values are copied to the given sdcard_spi_t struct.

Parameters

[out]	card	the device descriptor
[in]	params	parameters for this device (pins and spi device are initialized by this driver)

Returns

0 if the card could be initialized successfully

false if an error occurred while initializing the card

sdcard_spi_read_blocks()

int sdcard_spi_read_blocks	(	sdcard_spi_t *	card,
		uint32_t	blockaddr,
		void *	data,
		uint16_t	blocksize,
		uint16_t	nblocks,
		sd_rw_response_t *	state
	)

Reads data blocks (usually multiples of 512 Bytes) from card to buffer.

Parameters

[in]	card	Initialized sd-card struct
[in]	blockaddr	Start address to read from. Independent of the actual addressing scheme of the used card the address needs to be given as block address (e.g. 0, 1, 2... NOT: 0, 512... ). The driver takes care of mapping to byte addressing if needed.
[out]	data	Buffer to store the read data in. The user is responsible for providing a suitable buffer size.
[in]	blocksize	Size of data blocks. For now only 512 byte blocks are supported because only older (SDSC) cards support variable blocksizes anyway. With SDHC/SDXC-cards this is always fixed to 512 bytes. SDSC cards are automatically forced to use 512 byte as blocksize by the init procedure.
[in]	nblocks	Number of blocks to read
[out]	state	Contains information about the error state if something went wrong (if return value is lower than nblocks).

Returns

number of successfully read blocks (0 if no block was read).

sdcard_spi_write_blocks()

int sdcard_spi_write_blocks	(	sdcard_spi_t *	card,
		uint32_t	blockaddr,
		const void *	data,
		uint16_t	blocksize,
		uint16_t	nblocks,
		sd_rw_response_t *	state
	)

Writes data blocks (usually multiples of 512 Bytes) from buffer to card.

Parameters

[in]	card	Initialized sd-card struct
[in]	blockaddr	Start address to read from. Independent of the actual addressing scheme of the used card the address needs to be given as block address (e.g. 0, 1, 2... NOT: 0, 512... ). The driver takes care of mapping to byte addressing if needed.
[out]	data	Buffer that contains the data to be sent.
[in]	blocksize	Size of data blocks. For now only 512 byte blocks are supported because only older (SDSC) cards support variable blocksizes anyway. With SDHC/SDXC-cards this is always fixed to 512 bytes. SDSC cards are automatically forced to use 512 byte as blocksize by the init procedure.
[in]	nblocks	Number of blocks to write
[out]	state	Contains information about the error state if something went wrong (if return value is lower than nblocks).

Returns

number of successfully written blocks (0 if no block was written).