SD/SDIO/MMC 驱动程序
概述
SD/SDIO/MMC 驱动是一种基于 SDMMC 和 SD SPI 主机驱动的协议级驱动程序,目前已支持 SD 存储器、SDIO 卡和 eMMC 芯片。
SDMMC 主机驱动和 SD SPI 主机驱动(driver/sdmmc/include/driver/sdmmc_host.h 和 driver/spi/include/driver/sdspi_host.h)为以下功能提供 API:
发送命令至从设备
接收和发送数据
处理总线错误
初始化函数及配置函数:
如需初始化和配置 SDMMC 主机,请参阅 SDMMC 主机 API
如需初始化和配置 SD SPI 主机,请参阅 SD SPI 主机 API
本文档中所述的 SDMMC 协议层仅处理 SD 协议相关事项,例如卡初始化和数据传输命令。
协议层通过 sdmmc_host_t
结构体和主机协同工作,该结构体包含指向主机各类函数的指针。
应用示例
ESP-IDF storage/sd_card 目录下提供了 SDMMC 驱动与 FatFs 库组合使用的示例,演示了先初始化卡,然后使用 POSIX 和 C 库 API 向卡读写数据。请参考示例目录下 README.md 文件,查看更多详细信息。
复合卡(存储 + IO)
该驱动程序不支持 SD 复合卡,复合卡会被视为 IO 卡。
线程安全
多数应用程序仅需在一个任务中使用协议层。因此,协议层在 sdmmc_card_t
结构体或在访问 SDMMC 或 SD SPI 主机驱动程序时不使用任何类型的锁。这种锁通常在较高层级实现,例如文件系统驱动程序。
协议层 API
协议层具备 sdmmc_host_t
结构体,此结构体描述了 SD/MMC 主机驱动,列出了其功能,并提供指向驱动程序函数的指针。协议层将卡信息储存于 sdmmc_card_t
结构体中。向 SD/MMC 主机发送命令时,协议层使用 sdmmc_command_t
结构体来描述命令、参数、预期返回值和需传输的数据(如有)。
用于 SD 存储卡的 API
初始化主机,请调用主机驱动函数,例如
sdmmc_host_init()
和sdmmc_host_init_slot()
;初始化卡,请调用
sdmmc_card_init()
,并将参数host
(主机驱动信息)和参数card
(指向sdmmc_card_t
结构体的指针)传递给此函数。函数运行结束后,将会向sdmmc_card_t
结构体填充该卡的信息;读取或写入卡的扇区,请分别调用
sdmmc_read_sectors()
和sdmmc_write_sectors()
,并将参数card
(指向卡信息结构的指针)传递给函数;如果不再使用该卡,请调用主机驱动函数,例如
sdmmc_host_deinit()
,以禁用主机外设,并释放驱动程序分配的资源。
用于 eMMC 芯片的 API
从协议层的角度而言,eMMC 存储芯片与 SD 存储卡相同。尽管 eMMC 是芯片,不具备卡的外形,但由于协议相似 (sdmmc_card_t, sdmmc_card_init),用于 SD 卡的一些概念同样适用于 eMMC 芯片。注意,eMMC 芯片不可通过 SPI 使用,因此它与 SD API 主机驱动不兼容。
如需初始化 eMMC 内存并执行读/写操作,请参照上一章节 SD 卡操作步骤。
用于 SDIO 卡的 API
SDIO 卡初始化和检测过程与 SD 存储卡相同,唯一的区别是 SDIO 模式下数据传输命令不同。
在卡初始化和卡检测(通过运行 sdmmc_card_init()
)期间,驱动仅配置 IO 卡如下寄存器:
I/O 中止 (0x06) 寄存器:在该寄存器中设置 RES 位可重置卡的 IO 部分;
总线接口控制 (0x07) 寄存器:如果主机和插槽配置中启用 4 线模式,则驱动程序会尝试在该寄存器中设置总线宽度字段。如果字段设置成功,则从机支持 4 线模式,主机也切换至 4 线模式;
高速(0x13)寄存器:如果主机配置中启用高速模式,则该寄存器的 SHS 位会被设置。
注意,驱动程序不会在 (1) I/O 使能寄存器和 Int 使能寄存器,及 (2) I/O 块大小中,设置任何位。应用程序可通过调用 sdmmc_io_write_byte()
来设置相关位。
如需卡配置或传输数据,请根据您的具体情况选择下表中的函数:
操作 |
函数读取 |
函数写入 |
---|---|---|
使用 IO_RW_DIRECT (CMD52) 读写单个字节。 |
||
使用 IO_RW_EXTENDED (CMD53) 的字节模式读写多个字节。 |
||
块模式下,使用 IO_RW_EXTENDED (CMD53) 读写数据块。 |
使用 sdmmc_io_enable_int()
函数,应用程序可启用 SDIO 中断。在单线模式下使用 SDIO 时,还需要连接 D1 线来启用 SDIO 中断。
如果您需要应用程序保持等待直至发生 SDIO 中断,请使用 sdmmc_io_wait_int()
函数。
如果您需要与 ESP32 的 SDIO 从设备通信,请使用 ESSL 组件(ESP 串行从设备链接)。请参阅 ESP Serial Slave Link 和 peripherals/sdio/host。
API 参考
Header File
Functions
-
esp_err_t sdmmc_card_init(const sdmmc_host_t *host, sdmmc_card_t *out_card)
Probe and initialize SD/MMC card using given host
备注
Only SD cards (SDSC and SDHC/SDXC) are supported now. Support for MMC/eMMC cards will be added later.
- 参数
host -- pointer to structure defining host controller
out_card -- pointer to structure which will receive information about the card when the function completes
- 返回
ESP_OK on success
One of the error codes from SDMMC host controller
-
void sdmmc_card_print_info(FILE *stream, const sdmmc_card_t *card)
Print information about the card to a stream.
- 参数
stream -- stream obtained using fopen or fdopen
card -- card information structure initialized using sdmmc_card_init
-
esp_err_t sdmmc_get_status(sdmmc_card_t *card)
Get status of SD/MMC card
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
- 返回
ESP_OK on success
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_write_sectors(sdmmc_card_t *card, const void *src, size_t start_sector, size_t sector_count)
Write given number of sectors to SD/MMC card
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
src -- pointer to data buffer to read data from; data size must be equal to sector_count * card->csd.sector_size
start_sector -- sector where to start writing
sector_count -- number of sectors to write
- 返回
ESP_OK on success or sector_count equal to 0
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_read_sectors(sdmmc_card_t *card, void *dst, size_t start_sector, size_t sector_count)
Read given number of sectors from the SD/MMC card
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
dst -- pointer to data buffer to write into; buffer size must be at least sector_count * card->csd.sector_size
start_sector -- sector where to start reading
sector_count -- number of sectors to read
- 返回
ESP_OK on success or sector_count equal to 0
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_erase_sectors(sdmmc_card_t *card, size_t start_sector, size_t sector_count, sdmmc_erase_arg_t arg)
Erase given number of sectors from the SD/MMC card
备注
When sdmmc_erase_sectors used with cards in SDSPI mode, it was observed that card requires re-init after erase operation.
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
start_sector -- sector where to start erase
sector_count -- number of sectors to erase
arg -- erase command (CMD38) argument
- 返回
ESP_OK on success or sector_count equal to 0
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_can_discard(sdmmc_card_t *card)
Check if SD/MMC card supports discard
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
- 返回
ESP_OK if supported by the card/device
ESP_FAIL if not supported by the card/device
-
esp_err_t sdmmc_can_trim(sdmmc_card_t *card)
Check if SD/MMC card supports trim
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
- 返回
ESP_OK if supported by the card/device
ESP_FAIL if not supported by the card/device
-
esp_err_t sdmmc_mmc_can_sanitize(sdmmc_card_t *card)
Check if SD/MMC card supports sanitize
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
- 返回
ESP_OK if supported by the card/device
ESP_FAIL if not supported by the card/device
-
esp_err_t sdmmc_mmc_sanitize(sdmmc_card_t *card, uint32_t timeout_ms)
Sanitize the data that was unmapped by a Discard command
备注
Discard command has to precede sanitize operation. To discard, use MMC_DICARD_ARG with sdmmc_erase_sectors argument
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
timeout_ms -- timeout value in milliseconds required to sanitize the selected range of sectors.
- 返回
ESP_OK on success
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_full_erase(sdmmc_card_t *card)
Erase complete SD/MMC card
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
- 返回
ESP_OK on success
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_io_read_byte(sdmmc_card_t *card, uint32_t function, uint32_t reg, uint8_t *out_byte)
Read one byte from an SDIO card using IO_RW_DIRECT (CMD52)
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
function -- IO function number
reg -- byte address within IO function
out_byte -- [out] output, receives the value read from the card
- 返回
ESP_OK on success
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_io_write_byte(sdmmc_card_t *card, uint32_t function, uint32_t reg, uint8_t in_byte, uint8_t *out_byte)
Write one byte to an SDIO card using IO_RW_DIRECT (CMD52)
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
function -- IO function number
reg -- byte address within IO function
in_byte -- value to be written
out_byte -- [out] if not NULL, receives new byte value read from the card (read-after-write).
- 返回
ESP_OK on success
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_io_read_bytes(sdmmc_card_t *card, uint32_t function, uint32_t addr, void *dst, size_t size)
Read multiple bytes from an SDIO card using IO_RW_EXTENDED (CMD53)
This function performs read operation using CMD53 in byte mode. For block mode, see sdmmc_io_read_blocks.
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
function -- IO function number
addr -- byte address within IO function where reading starts
dst -- buffer which receives the data read from card
size -- number of bytes to read
- 返回
ESP_OK on success
ESP_ERR_INVALID_SIZE if size exceeds 512 bytes
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_io_write_bytes(sdmmc_card_t *card, uint32_t function, uint32_t addr, const void *src, size_t size)
Write multiple bytes to an SDIO card using IO_RW_EXTENDED (CMD53)
This function performs write operation using CMD53 in byte mode. For block mode, see sdmmc_io_write_blocks.
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
function -- IO function number
addr -- byte address within IO function where writing starts
src -- data to be written
size -- number of bytes to write
- 返回
ESP_OK on success
ESP_ERR_INVALID_SIZE if size exceeds 512 bytes
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_io_read_blocks(sdmmc_card_t *card, uint32_t function, uint32_t addr, void *dst, size_t size)
Read blocks of data from an SDIO card using IO_RW_EXTENDED (CMD53)
This function performs read operation using CMD53 in block mode. For byte mode, see sdmmc_io_read_bytes.
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
function -- IO function number
addr -- byte address within IO function where writing starts
dst -- buffer which receives the data read from card
size -- number of bytes to read, must be divisible by the card block size.
- 返回
ESP_OK on success
ESP_ERR_INVALID_SIZE if size is not divisible by 512 bytes
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_io_write_blocks(sdmmc_card_t *card, uint32_t function, uint32_t addr, const void *src, size_t size)
Write blocks of data to an SDIO card using IO_RW_EXTENDED (CMD53)
This function performs write operation using CMD53 in block mode. For byte mode, see sdmmc_io_write_bytes.
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
function -- IO function number
addr -- byte address within IO function where writing starts
src -- data to be written
size -- number of bytes to read, must be divisible by the card block size.
- 返回
ESP_OK on success
ESP_ERR_INVALID_SIZE if size is not divisible by 512 bytes
One of the error codes from SDMMC host controller
-
esp_err_t sdmmc_io_enable_int(sdmmc_card_t *card)
Enable SDIO interrupt in the SDMMC host
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
- 返回
ESP_OK on success
ESP_ERR_NOT_SUPPORTED if the host controller does not support IO interrupts
-
esp_err_t sdmmc_io_wait_int(sdmmc_card_t *card, TickType_t timeout_ticks)
Block until an SDIO interrupt is received
Slave uses D1 line to signal interrupt condition to the host. This function can be used to wait for the interrupt.
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
timeout_ticks -- time to wait for the interrupt, in RTOS ticks
- 返回
ESP_OK if the interrupt is received
ESP_ERR_NOT_SUPPORTED if the host controller does not support IO interrupts
ESP_ERR_TIMEOUT if the interrupt does not happen in timeout_ticks
-
esp_err_t sdmmc_io_get_cis_data(sdmmc_card_t *card, uint8_t *out_buffer, size_t buffer_size, size_t *inout_cis_size)
Get the data of CIS region of an SDIO card.
You may provide a buffer not sufficient to store all the CIS data. In this case, this function stores as much data into your buffer as possible. Also, this function will try to get and return the size required for you.
- 参数
card -- pointer to card information structure previously initialized using sdmmc_card_init
out_buffer -- Output buffer of the CIS data
buffer_size -- Size of the buffer.
inout_cis_size -- Mandatory, pointer to a size, input and output.
input: Limitation of maximum searching range, should be 0 or larger than buffer_size. The function searches for CIS_CODE_END until this range. Set to 0 to search infinitely.
output: The size required to store all the CIS data, if CIS_CODE_END is found.
- 返回
ESP_OK: on success
ESP_ERR_INVALID_RESPONSE: if the card does not (correctly) support CIS.
ESP_ERR_INVALID_SIZE: CIS_CODE_END found, but buffer_size is less than required size, which is stored in the inout_cis_size then.
ESP_ERR_NOT_FOUND: if the CIS_CODE_END not found. Increase input value of inout_cis_size or set it to 0, if you still want to search for the end; output value of inout_cis_size is invalid in this case.
and other error code return from sdmmc_io_read_bytes
-
esp_err_t sdmmc_io_print_cis_info(uint8_t *buffer, size_t buffer_size, FILE *fp)
Parse and print the CIS information of an SDIO card.
备注
Not all the CIS codes and all kinds of tuples are supported. If you see some unresolved code, you can add the parsing of these code in sdmmc_io.c and contribute to the IDF through the Github repository.
using sdmmc_card_init
- 参数
buffer -- Buffer to parse
buffer_size -- Size of the buffer.
fp -- File pointer to print to, set to NULL to print to stdout.
- 返回
ESP_OK: on success
ESP_ERR_NOT_SUPPORTED: if the value from the card is not supported to be parsed.
ESP_ERR_INVALID_SIZE: if the CIS size fields are not correct.
Header File
Structures
-
struct sdmmc_csd_t
Decoded values from SD card Card Specific Data register
-
struct sdmmc_cid_t
Decoded values from SD card Card IDentification register
-
struct sdmmc_scr_t
Decoded values from SD Configuration Register Note: When new member is added, update reserved bits accordingly
Public Members
-
uint32_t sd_spec
SD Physical layer specification version, reported by card
-
uint32_t erase_mem_state
data state on card after erase whether 0 or 1 (card vendor dependent)
-
uint32_t bus_width
bus widths supported by card: BIT(0) — 1-bit bus, BIT(2) — 4-bit bus
-
uint32_t reserved
reserved for future expansion
-
uint32_t rsvd_mnf
reserved for manufacturer usage
-
uint32_t sd_spec
-
struct sdmmc_ssr_t
Decoded values from SD Status Register Note: When new member is added, update reserved bits accordingly
Public Members
-
uint32_t alloc_unit_kb
Allocation unit of the card, in multiples of kB (1024 bytes)
-
uint32_t erase_size_au
Erase size for the purpose of timeout calculation, in multiples of allocation unit
-
uint32_t cur_bus_width
SD current bus width
-
uint32_t discard_support
SD discard feature support
-
uint32_t fule_support
SD FULE (Full User Area Logical Erase) feature support
-
uint32_t erase_timeout
Timeout (in seconds) for erase of a single allocation unit
-
uint32_t erase_offset
Constant timeout offset (in seconds) for any erase operation
-
uint32_t reserved
reserved for future expansion
-
uint32_t alloc_unit_kb
-
struct sdmmc_ext_csd_t
Decoded values of Extended Card Specific Data
-
struct sdmmc_switch_func_rsp_t
SD SWITCH_FUNC response buffer
Public Members
-
uint32_t data[512 / 8 / sizeof(uint32_t)]
response data
-
uint32_t data[512 / 8 / sizeof(uint32_t)]
-
struct sdmmc_command_t
SD/MMC command information
Public Members
-
uint32_t opcode
SD or MMC command index
-
uint32_t arg
SD/MMC command argument
-
sdmmc_response_t response
response buffer
-
void *data
buffer to send or read into
-
size_t datalen
length of data buffer
-
size_t blklen
block length
-
int flags
see below
-
uint32_t timeout_ms
response timeout, in milliseconds
-
uint32_t opcode
-
struct sdmmc_host_t
SD/MMC Host description
This structure defines properties of SD/MMC host and functions of SD/MMC host which can be used by upper layers.
Public Members
-
uint32_t flags
flags defining host properties
-
int slot
slot number, to be passed to host functions
-
int max_freq_khz
max frequency supported by the host
-
float io_voltage
I/O voltage used by the controller (voltage switching is not supported)
-
size_t (*get_bus_width)(int slot)
host function to get bus width
-
esp_err_t (*set_cclk_always_on)(int slot, bool cclk_always_on)
host function to set whether the clock is always enabled
-
esp_err_t (*do_transaction)(int slot, sdmmc_command_t *cmdinfo)
host function to do a transaction
-
esp_err_t (*io_int_wait)(int slot, TickType_t timeout_ticks)
Host function to wait for SDIO interrupt line to be active
-
int command_timeout_ms
timeout, in milliseconds, of a single command. Set to 0 to use the default value.
-
uint32_t flags
-
struct sdmmc_card_t
SD/MMC card information structure
Public Members
-
sdmmc_host_t host
Host with which the card is associated
-
uint32_t ocr
OCR (Operation Conditions Register) value
-
sdmmc_cid_t cid
decoded CID (Card IDentification) register value
-
sdmmc_response_t raw_cid
raw CID of MMC card to be decoded after the CSD is fetched in the data transfer mode
-
sdmmc_csd_t csd
decoded CSD (Card-Specific Data) register value
-
sdmmc_scr_t scr
decoded SCR (SD card Configuration Register) value
-
sdmmc_ssr_t ssr
decoded SSR (SD Status Register) value
-
sdmmc_ext_csd_t ext_csd
decoded EXT_CSD (Extended Card Specific Data) register value
-
uint16_t rca
RCA (Relative Card Address)
-
uint16_t max_freq_khz
Maximum frequency, in kHz, supported by the card
-
int real_freq_khz
Real working frequency, in kHz, configured on the host controller
-
uint32_t is_mem
Bit indicates if the card is a memory card
-
uint32_t is_sdio
Bit indicates if the card is an IO card
-
uint32_t is_mmc
Bit indicates if the card is MMC
-
uint32_t num_io_functions
If is_sdio is 1, contains the number of IO functions on the card
-
uint32_t log_bus_width
log2(bus width supported by card)
-
uint32_t is_ddr
Card supports DDR mode
-
uint32_t reserved
Reserved for future expansion
-
sdmmc_host_t host
Macros
-
SDMMC_HOST_FLAG_1BIT
host supports 1-line SD and MMC protocol
-
SDMMC_HOST_FLAG_4BIT
host supports 4-line SD and MMC protocol
-
SDMMC_HOST_FLAG_8BIT
host supports 8-line MMC protocol
-
SDMMC_HOST_FLAG_SPI
host supports SPI protocol
-
SDMMC_HOST_FLAG_DDR
host supports DDR mode for SD/MMC
-
SDMMC_HOST_FLAG_DEINIT_ARG
host
deinit
function called with the slot argument
-
SDMMC_FREQ_DEFAULT
SD/MMC Default speed (limited by clock divider)
-
SDMMC_FREQ_HIGHSPEED
SD High speed (limited by clock divider)
-
SDMMC_FREQ_PROBING
SD/MMC probing speed
-
SDMMC_FREQ_52M
MMC 52MHz speed
-
SDMMC_FREQ_26M
MMC 26MHz speed
Type Definitions
-
typedef uint32_t sdmmc_response_t[4]
SD/MMC command response buffer
Enumerations
-
enum sdmmc_erase_arg_t
SD/MMC erase command(38) arguments SD: ERASE: Erase the write blocks, physical/hard erase.
DISCARD: Card may deallocate the discarded blocks partially or completely. After discard operation the previously written data may be partially or fully read by the host depending on card implementation.
MMC: ERASE: Does TRIM, applies erase operation to write blocks instead of Erase Group.
DISCARD: The Discard function allows the host to identify data that is no longer required so that the device can erase the data if necessary during background erase events. Applies to write blocks instead of Erase Group After discard operation, the original data may be remained partially or fully accessible to the host dependent on device.
Values:
-
enumerator SDMMC_ERASE_ARG
Erase operation on SD, Trim operation on MMC
-
enumerator SDMMC_DISCARD_ARG
Discard operation for SD/MMC
-
enumerator SDMMC_ERASE_ARG