px_sd.h : SD Card Driver

Description

Driver that communicates with an SD (Secure Digital) Card using SPI.

File(s):

• devices/mem/inc/px_sd.h
• devices/mem/src/px_sd_spi.c

Reference:

• 1. SD Specifications Part 1 Physical Layer Simplified Specification 4.10
• 2. ChaN's How to Use MMC/SDC
• 3. Maxim - SD Media Format Expands the MAXQ2000's Space for Nonvolatile Data Storage

Data Structures
struct	px_sd_cid_t
	CID - Card ID register; Ref 1. Paragraph "5.2 CID Register", page 113. More...
struct	px_sd_csd_t
	CSD - Card Specific Data register; Paragraph "5.3 CSD Register", page 114. More...
union	px_sd_csd_t.ver
struct	px_sd_csd_t.ver.csd_1_0
struct	px_sd_csd_t.ver.csd_2_0

Macros
#define	PX_SD_MAX_SPI_CLOCK_HZ   25000000ul
	Maximum SPI Clock rate. More...
#define	PX_SD_SPI_MODE   PX_SPI_MODE0
	SPI Clock / Data phase. More...
#define	PX_SD_SPI_DATA_ORDER   PX_SPI_DATA_ORDER_MSB
	SPI Data order. More...
#define	PX_SD_SPI_MO_DUMMY_BYTE   0xff
	SPI Master Out dummy byte. More...
#define	PX_SD_BLOCK_SIZE   512ul
	Size of each data block. More...

Functions
void	px_sd_init (px_spi_handle_t *handle)
	Initialise driver. More...
bool	px_sd_reset (void)
	Detect and reset SD card. More...
bool	px_sd_rd_cid (px_sd_cid_t *cid)
	Read Card ID Register. More...
bool	px_sd_rd_csd (px_sd_csd_t *csd)
	Read Card Specific Data. More...
bool	px_sd_get_status (uint16_t *status)
	Read Card Status. More...
uint32_t	px_sd_get_capacity_in_blocks (const px_sd_csd_t *csd)
	Extract and calculate card capacity from Card Specific Data (CSD). More...
bool	px_sd_rd_block (uint8_t *data, uint32_t block_adr)
	Read a data block from the SD card. More...
uint8_t	px_sd_rd_blocks (uint8_t *data, uint32_t block_adr, uint8_t nr_of_blocks)
	Read a number of data blocks from the SD card. More...
bool	px_sd_wr_block (const uint8_t *data, uint32_t block_adr)
	Write a data block to the SD card. More...
uint8_t	px_sd_wr_blocks (const uint8_t *data, uint32_t block_adr, uint8_t nr_of_blocks)
	Write a number of data blocks to the SD card. More...
bool	px_sd_wait_wr_is_finished (void)
	Wait up to 500 ms for write block transaction to finish. More...

---

Data Structure Documentation

px_sd_cid_t

struct px_sd_cid_t

CID - Card ID register; Ref 1. Paragraph "5.2 CID Register", page 113.

Definition at line 68 of file px_sd.h.

Data Fields
uint8_t	mid	Manufacturer ID.
char	oid[2]	OEM/Application ID [2 ASCII chars].
char	pnm[5]	Product name [5 ASCII chars].
uint8_t	prv	BCD Product revision [Major.Minor].
uint32_t	psn	Product serial number
uint8_t	year_hi: 4	Manufacturing date [xYYM].
uint8_t	res1: 4
uint8_t	year_lo: 4	Manufacturing date [xYYM].
uint8_t	month: 4	Manufacturing date [xYYM].
uint8_t	crc7_end_bit

px_sd_csd_t

struct px_sd_csd_t

CSD - Card Specific Data register; Paragraph "5.3 CSD Register", page 114.

Definition at line 83 of file px_sd.h.

Data Fields
uint8_t	reserved1: 6
uint8_t	csd_structure: 2	CSD structure version 1.0 or 2.0.
uint8_t	taac	data read access-time-1
uint8_t	nsac	data read access-time-2 in CLK cycles (NSAC*100)
uint8_t	tran_speed	max. data transfer rate
uint8_t	ccc_hi	card command classes
uint8_t	read_bl_len: 4	max. read data block length
uint8_t	ccc_lo: 4	card command classes
union px_sd_csd_t.ver	ver
uint8_t	write_bl_len_hi: 2	max. write data block length
uint8_t	r2w_factor: 3	write speed factor
uint8_t	reserved3: 2
uint8_t	wp_grp_enable: 1	write protect group enable
uint8_t	reserved4: 5
uint8_t	write_partial: 1	partial blocks for write allowed
uint8_t	write_bl_len_low: 2	max. write data block length
uint8_t	reserved5: 2
uint8_t	file_format: 2	File format.
uint8_t	tmp_write_protect: 1	temporary write protection
uint8_t	perm_write_protect: 1	permanent write protection
uint8_t	copy: 1	copy flag
uint8_t	file_format_grp: 1	File format.
uint8_t	crc7_end_bit	CRC.

px_sd_csd_t.ver

union px_sd_csd_t.ver

Definition at line 100 of file px_sd.h.

px_sd_csd_t.ver.csd_1_0

struct px_sd_csd_t.ver.csd_1_0

Definition at line 102 of file px_sd.h.

Data Fields
uint8_t	c_size_hi: 2	device size
uint8_t	reserved2: 2
uint8_t	dsr_imp: 1	DSR implemented.
uint8_t	read_blk_misalign: 1	read block misalignment
uint8_t	write_blk_misalign: 1	write block misalignment
uint8_t	read_bl_partial: 1	partial blocks for read allowed
uint8_t	c_size_mid	device size
uint8_t	vdd_r_curr_max: 3	max. read current at VDD max
uint8_t	vdd_r_curr_min: 3	max. read current at VDD min
uint8_t	c_size_lo: 2	device size
uint8_t	c_size_mult_hi: 2	device size multiplier
uint8_t	vdd_w_cur_max: 3	max. write current at VDD max
uint8_t	vdd_w_curr_min: 3	max. write current at VDD min
uint8_t	sector_size_hi: 6	erase sector size
uint8_t	erase_blk_en: 1	erase single block enable
uint8_t	c_size_mult_lo: 1	device size multiplier
uint8_t	wp_grp_size: 7	write protect group size
uint8_t	sector_size_lo: 1	erase sector size

px_sd_csd_t.ver.csd_2_0

struct px_sd_csd_t.ver.csd_2_0

Definition at line 130 of file px_sd.h.

Data Fields
uint8_t	reserved2: 4
uint8_t	dsr_imp: 1	DSR implemented.
uint8_t	read_blk_misalign: 1	read block misalignment
uint8_t	write_blk_misalign: 1	write block misalignment
uint8_t	read_bl_partial: 1	partial blocks for read allowed
uint8_t	c_size_hi: 6	device size
uint8_t	reserved3: 2
uint8_t	c_size_mid: 8	device size
uint8_t	c_size_lo: 8	device size
uint8_t	sector_size_hi: 6	erase sector size
uint8_t	erase_blk_en: 1	erase single block enable
uint8_t	reserved4: 1
uint8_t	wp_grp_size: 7	write protect group size
uint8_t	sector_size_lo: 1	erase sector size

Macro Definition Documentation

PX_SD_MAX_SPI_CLOCK_HZ

#define PX_SD_MAX_SPI_CLOCK_HZ   25000000ul

Maximum SPI Clock rate.

Definition at line 47 of file px_sd.h.

PX_SD_SPI_MODE

#define PX_SD_SPI_MODE   PX_SPI_MODE0

SPI Clock / Data phase.

Definition at line 49 of file px_sd.h.

PX_SD_SPI_DATA_ORDER

#define PX_SD_SPI_DATA_ORDER   PX_SPI_DATA_ORDER_MSB

SPI Data order.

Definition at line 51 of file px_sd.h.

PX_SD_SPI_MO_DUMMY_BYTE

#define PX_SD_SPI_MO_DUMMY_BYTE   0xff

SPI Master Out dummy byte.

Definition at line 53 of file px_sd.h.

PX_SD_BLOCK_SIZE

#define PX_SD_BLOCK_SIZE   512ul

Size of each data block.

Definition at line 56 of file px_sd.h.

Function Documentation

px_sd_init()

void px_sd_init

(

px_spi_handle_t *

handle

)

Initialise driver.

Parameters

handle

SPI handle to use for SPI slave device

Definition at line 325 of file px_sd.c.

px_sd_reset()

bool px_sd_reset

(

void

)

Detect and reset SD card.

Return values

true	SD card detected and reset to known state
false	SD card not detected or not supported

Definition at line 331 of file px_sd.c.

px_sd_rd_cid()

bool px_sd_rd_cid

(

px_sd_cid_t *

cid

)

Read Card ID Register.

Parameters

cid	Structure to store data

Return values

true	Card ID register succesfully read
false	Error while trying to read Card ID register

Definition at line 514 of file px_sd.c.

px_sd_rd_csd()

bool px_sd_rd_csd

(

px_sd_csd_t *

csd

)

Read Card Specific Data.

Parameters

csd	Structure to store data

Return values

true	Card Specific Data succesfully read
false	Error while trying to read Card Specific Data

Definition at line 539 of file px_sd.c.

px_sd_get_status()

bool px_sd_get_status

(

uint16_t *

status

)

Read Card Status.

Parameters

status

Variable to store card status in

Return values

true	Card Status succesfully read
false	Error while trying to read Card Status

Definition at line 571 of file px_sd.c.

px_sd_get_capacity_in_blocks()

uint32_t px_sd_get_capacity_in_blocks

(

const px_sd_csd_t *

csd

)

Extract and calculate card capacity from Card Specific Data (CSD).

Parameters

csd	Card Specific Data

Returns

uint32_t Card capacity in number of blocks (see PX_SD_BLOCK_SIZE)

Definition at line 593 of file px_sd.c.

px_sd_rd_block()

bool px_sd_rd_block	(	uint8_t *	data,
		uint32_t	block_adr
	)

Read a data block from the SD card.

The data block size is PX_SD_BLOCK_SIZE and the specified array must be big enough to accept the whole data block.

Parameters

data	Pointer to array where data block must be stored
block_adr	Address of block to read.

Return values

true	Data block succcesfully read
false	Error while trying to read data block

Definition at line 652 of file px_sd.c.

px_sd_rd_blocks()

uint8_t px_sd_rd_blocks	(	uint8_t *	data,
		uint32_t	block_adr,
		uint8_t	nr_of_blocks
	)

Read a number of data blocks from the SD card.

The data block size is PX_SD_BLOCK_SIZE and the specified array must be big enough to accept (nr_of_blocks x PX_SD_BLOCK_SIZE).

Parameters

data	Pointer to array where data blocks must be stored
block_adr	Address of start block to read
nr_of_blocks	Number of blocks to read

Returns

uint8_t Number of blocks succesfully read

Definition at line 685 of file px_sd.c.

px_sd_wr_block()

bool px_sd_wr_block	(	const uint8_t *	data,
		uint32_t	block_adr
	)

Write a data block to the SD card.

The data block size is PX_SD_BLOCK_SIZE and the specified array must contain the whole data block. Poll px_sd_wait_write_finished() to find out when write operation has finished, e.g. before powering down SD card.

Parameters

data	Pointer to array containing data block content to be written
block_adr	Address of block to write.

Return values

true	Data block succcesfully written
false	Error while trying to write data block

Definition at line 743 of file px_sd.c.

px_sd_wr_blocks()

uint8_t px_sd_wr_blocks	(	const uint8_t *	data,
		uint32_t	block_adr,
		uint8_t	nr_of_blocks
	)

Write a number of data blocks to the SD card.

The data block size is PX_SD_BLOCK_SIZE and the specified array must contain (nr_of_blocks x PX_SD_BLOCK_SIZE). Poll px_sd_wait_write_finished() to find out when write operation has finished, e.g. before powering down SD card.

Parameters

data	Pointer to array containing content to be written
block_adr	Address of start block to write.
nr_of_blocks	Number of blocks to write

Returns

uint8_t Number of blocks succesfully written

Definition at line 779 of file px_sd.c.

px_sd_wait_wr_is_finished()

bool px_sd_wait_wr_is_finished

(

void

)

Wait up to 500 ms for write block transaction to finish.

Return values

true	Write operation finished
false	Timed-out waiting for SD card to be ready

Definition at line 858 of file px_sd.c.