SD/SDIO/MMC Driver

[中文]

Overview

The SD/SDIO/MMC driver currently supports SD memory, SDIO cards, and eMMC chips. This is a protocol layer driver (sdmmc/include/sdmmc_cmd.h) which can be implemented by:

Protocol Layer vs Host Layer

The SDMMC protocol layer described in this document handles the specifics of the SD protocol, such as the card initialization flow and variours data transfer command flows. The protocol layer works with the host via the sdmmc_host_t structure. This structure contains pointers to various functions of the host.

Host layer driver(s) implement the protocol layer driver by supporting these functions:

  • Sending commands to slave devices

  • Sending and receiving data

  • Handling error conditions within the bus

SD Host Side Component Architecture

Application Example

An example which combines the SDMMC driver with the FATFS library is provided in the storage/sd_card directory of ESP-IDF examples. This example initializes the card, then writes and reads data from it using POSIX and C library APIs. See README.md file in the example directory for more information.

Combo (Memory + IO) Cards

The driver does not support SD combo cards. Combo cards are treated as IO cards.

Thread Safety

Most applications need to use the protocol layer only in one task. For this reason, the protocol layer does not implement any kind of locking on the sdmmc_card_t structure, or when accessing SDMMC or SD SPI host drivers. Such locking is usually implemented on a higher layer, e.g., in the filesystem driver.

API Reference

Header File

  • components/sdmmc/include/sdmmc_cmd.h

  • This header file can be included with:

    #include "sdmmc_cmd.h"

  • This header file is a part of the API provided by the sdmmc component. To declare that your component depends on sdmmc, add the following to your CMakeLists.txt:

    REQUIRES sdmmc

    or

    PRIV_REQUIRES sdmmc

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

Note

Only SD cards (SDSC and SDHC/SDXC) are supported now. Support for MMC/eMMC cards will be added later.

Parameters

  • host -- pointer to structure defining host controller

  • out_card -- pointer to structure which will receive information about the card when the function completes

Returns

  • 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.

Parameters

  • 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

Parameters

card -- pointer to card information structure previously initialized using sdmmc_card_init

Returns

  • 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

Parameters

  • 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

Returns

  • 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

Parameters

  • 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

Returns

  • 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

Note

When sdmmc_erase_sectors used with cards in SDSPI mode, it was observed that card requires re-init after erase operation.

Parameters

  • 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

Returns

  • 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

Parameters

card -- pointer to card information structure previously initialized using sdmmc_card_init

Returns

  • 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

Parameters

card -- pointer to card information structure previously initialized using sdmmc_card_init

Returns

  • 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

Parameters

card -- pointer to card information structure previously initialized using sdmmc_card_init

Returns

  • 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

Note

Discard command has to precede sanitize operation. To discard, use MMC_DICARD_ARG with sdmmc_erase_sectors argument

Parameters

  • 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.

Returns

  • 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

Parameters

card -- pointer to card information structure previously initialized using sdmmc_card_init

Returns

  • 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)

Parameters

  • 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

Returns

  • 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)

Parameters

  • 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).

Returns

  • 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.

Parameters

  • 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. Aligned to 4 byte boundary unless SDMMC_HOST_FLAG_ALLOC_ALIGNED_BUF flag is set when calling sdmmc_card_init. The flag is mandatory when the buffer is behind the cache.

  • size -- number of bytes to read, 1 to 512.

Returns

  • 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.

Parameters

  • 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. Aligned to 4 byte boundary unless SDMMC_HOST_FLAG_ALLOC_ALIGNED_BUF flag is set when calling sdmmc_card_init. The flag is mandatory when the buffer is behind the cache.

  • size -- number of bytes to write, 1 to 512.

Returns

  • 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.

Parameters

  • 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. Aligned to 4 byte boundary, and also cache line size if the buffer is behind the cache.

  • size -- number of bytes to read, must be divisible by the card block size.

Returns

  • 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.

Parameters

  • 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. Aligned to 4 byte boundary, and also cache line size if the buffer is behind the cache.

  • size -- number of bytes to read, must be divisible by the card block size.

Returns

  • 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

Parameters

card -- pointer to card information structure previously initialized using sdmmc_card_init

Returns

  • 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.

Parameters

  • card -- pointer to card information structure previously initialized using sdmmc_card_init

  • timeout_ticks -- time to wait for the interrupt, in RTOS ticks

Returns

  • 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.

Parameters

  • 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.

Returns

  • 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.

Note

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

Parameters

  • buffer -- Buffer to parse

  • buffer_size -- Size of the buffer.

  • fp -- File pointer to print to, set to NULL to print to stdout.

Returns

  • 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

  • components/esp_driver_sdmmc/include/driver/sdmmc_types.h

  • This header file can be included with:

    #include "driver/sdmmc_types.h"

  • This header file is a part of the API provided by the esp_driver_sdmmc component. To declare that your component depends on esp_driver_sdmmc, add the following to your CMakeLists.txt:

    REQUIRES esp_driver_sdmmc

    or

    PRIV_REQUIRES esp_driver_sdmmc

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