fatfs::Esp32SdmmcIO Class Reference

Accessing an SD card via the ESP32 SDMMC interface using low-level API. More...

#include <Esp32SdmmcIO.h>

Inheritance diagram for fatfs::Esp32SdmmcIO:

Collaboration diagram for fatfs::Esp32SdmmcIO:

Public Member Functions
	Esp32SdmmcIO ()
	Default constructor - card must be initialized with begin()
	Esp32SdmmcIO (bool mode1bit, int max_freq_khz=SDMMC_FREQ_DEFAULT)
	Constructor with bus mode and frequency.
	Esp32SdmmcIO (bool mode1bit, int max_freq_khz, const sdmmc_host_t &host_cfg, const sdmmc_slot_config_t &slot_cfg)
	Constructor with custom host and slot configuration.
	~Esp32SdmmcIO ()
	Destructor - cleanup resources.
bool	begin (bool mode1bit=false, int max_freq_khz=SDMMC_FREQ_DEFAULT)
	Initialize the SDMMC interface and mount the SD card.
bool	begin (bool mode1bit, int max_freq_khz, sdmmc_host_t host_cfg, sdmmc_slot_config_t slot_cfg)
	Initialize with custom host and slot configuration.
void	end ()
	End SDMMC interface and unmount SD card.
DSTATUS	disk_initialize (BYTE drv) override
	Initialize disk drive.
DSTATUS	disk_status (BYTE drv) override
	Get disk status.
DRESULT	disk_read (BYTE drv, BYTE *buff, LBA_t sector, UINT count) override
	Read sector(s)
DRESULT	disk_write (BYTE drv, const BYTE *buff, LBA_t sector, UINT count) override
	Write sector(s)
DRESULT	disk_ioctl (BYTE drv, ioctl_cmd_t cmd, void *buff) override
	Miscellaneous drive controls.
uint64_t	cardSize () const
	Get the card size in bytes.
uint8_t	cardType () const
	Get the card type flags.
uint64_t	totalSectors () const
	Get the total number of sectors.
sdmmc_card_t *	getCard ()
	Get pointer to the card structure (for advanced use)
bool	isMMC () const
	Check if card is MMC.
uint32_t	getFreqKHz () const
	Get card frequency in kHz.
virtual FRESULT	mount (FatFs &fs)
	mount the file system - implementation at end of header to avoid recursive include
virtual FRESULT	un_mount (FatFs &fs)
	unmount the file system - implementation at end of header to avoid recursive include

Public Attributes
FATFS	fatfs

Protected Attributes
volatile DSTATUS	stat = STA_NOINIT
	Physical drive status.
BYTE	CardType = 0
	Card type flags.
sdmmc_card_t *	card
	Pointer to card structure.
sdmmc_host_t	host_config
	Host configuration.
sdmmc_slot_config_t	slot_config
	Slot configuration.
bool	auto_init
	Whether to auto-init on first use.
bool	init_mode1bit
	Stored 1-bit mode setting.
int	init_max_freq_khz
	Stored max frequency setting.

Detailed Description

Accessing an SD card via the ESP32 SDMMC interface using low-level API.

This driver uses the ESP32's built-in SDMMC controller for high-speed SD card access via the ESP-IDF low-level driver API. It supports both 1-bit and 4-bit bus modes with custom pin configuration.

Example usage:

#include "fatfs.h"
using namespace fatfs;
 
// Method 1: Default constructor + begin()
Esp32SdmmcIO driver1;
FatFs fs1;
 
void setup() {
  if (!driver1.begin(false, SDMMC_FREQ_DEFAULT)) {
    Serial.println("Card Mount Failed");
    return;
  }
  driver1.mount(fs1);
}
 
// Method 2: Constructor with config (auto-init on mount)
Esp32SdmmcIO driver2(false, SDMMC_FREQ_DEFAULT);  // 4-bit, 20MHz
FatFs fs2;
 
void setup() {
  // Card initializes automatically when mounting
  driver2.mount(fs2);
}

Constructor & Destructor Documentation

Esp32SdmmcIO() [1/2]

fatfs::Esp32SdmmcIO::Esp32SdmmcIO ( bool  mode1bit, int  max_freq_khz = SDMMC_FREQ_DEFAULT  )

inline

Constructor with bus mode and frequency.

Parameters

mode1bit	Use 1-bit mode (true) or 4-bit mode (false, default)
max_freq_khz	Maximum frequency in kHz (default: SDMMC_FREQ_DEFAULT)

Note: Card initialization is deferred until disk_initialize() is called, or you can call begin() explicitly.

Esp32SdmmcIO() [2/2]

fatfs::Esp32SdmmcIO::Esp32SdmmcIO ( bool  mode1bit, int  max_freq_khz, const sdmmc_host_t &  host_cfg, const sdmmc_slot_config_t &  slot_cfg  )

inline

Constructor with custom host and slot configuration.

Parameters

mode1bit	Use 1-bit mode (true) or 4-bit mode (false)
max_freq_khz	Maximum frequency in kHz
host_cfg	Host configuration (from SDMMC_HOST_DEFAULT())
slot_cfg	Slot configuration (from SDMMC_SLOT_CONFIG_DEFAULT())

Note: Card initialization is deferred until disk_initialize() is called, or you can call begin() explicitly.

Member Function Documentation

begin() [1/2]

bool fatfs::Esp32SdmmcIO::begin ( bool  mode1bit, int  max_freq_khz, sdmmc_host_t  host_cfg, sdmmc_slot_config_t  slot_cfg  )

inline

Initialize with custom host and slot configuration.

Parameters

mode1bit	Use 1-bit mode (true) or 4-bit mode (false)
max_freq_khz	Maximum frequency in kHz
host_cfg	Host configuration (from SDMMC_HOST_DEFAULT())
slot_cfg	Slot configuration (from SDMMC_SLOT_CONFIG_DEFAULT())

Returns

true if initialization succeeded, false otherwise

begin() [2/2]

bool fatfs::Esp32SdmmcIO::begin ( bool  mode1bit = false, int  max_freq_khz = SDMMC_FREQ_DEFAULT  )

inline

Initialize the SDMMC interface and mount the SD card.

Parameters

mode1bit	Use 1-bit mode (true) or 4-bit mode (false, default)
max_freq_khz	Maximum frequency in kHz (default: SDMMC_FREQ_DEFAULT)

Returns

true if initialization succeeded, false otherwise

cardSize()

uint64_t fatfs::Esp32SdmmcIO::cardSize ( ) const

inline

Get the card size in bytes.

Returns

Card size in bytes

cardType()

uint8_t fatfs::Esp32SdmmcIO::cardType ( ) const

inline

Get the card type flags.

Returns

Card type flags (CT_MMC, CT_SD1, CT_SD2, CT_BLOCK)

disk_initialize()

DSTATUS fatfs::Esp32SdmmcIO::disk_initialize ( BYTE  drv )

inlineoverridevirtual

Initialize disk drive.

Parameters

drv	Physical drive number (0)

Returns

Disk status

Reimplemented from fatfs::BaseIO.

disk_ioctl()

DRESULT fatfs::Esp32SdmmcIO::disk_ioctl ( BYTE  drv, ioctl_cmd_t  cmd, void *  buff  )

inlineoverridevirtual

Miscellaneous drive controls.

Parameters

drv	Physical drive number (0)
cmd	Control command code
buff	Pointer to the control data

Returns

Result code

Reimplemented from fatfs::BaseIO.

disk_read()

DRESULT fatfs::Esp32SdmmcIO::disk_read ( BYTE  drv, BYTE *  buff, LBA_t  sector, UINT  count  )

inlineoverridevirtual

Read sector(s)

Parameters

drv	Physical drive number (0)
buff	Pointer to the data buffer to store read data
sector	Start sector number (LBA)
count	Number of sectors to read (1..128)

Returns

Result code

Reimplemented from fatfs::BaseIO.

disk_status()

DSTATUS fatfs::Esp32SdmmcIO::disk_status ( BYTE  drv )

inlineoverridevirtual

Get disk status.

Parameters

drv	Physical drive number (0)

Returns

Disk status

Reimplemented from fatfs::BaseIO.

disk_write()

DRESULT fatfs::Esp32SdmmcIO::disk_write ( BYTE  drv, const BYTE *  buff, LBA_t  sector, UINT  count  )

inlineoverridevirtual

Write sector(s)

Parameters

drv	Physical drive number (0)
buff	Pointer to the data to write
sector	Start sector number (LBA)
count	Number of sectors to write (1..128)

Returns

Result code

Reimplemented from fatfs::BaseIO.

getCard()

sdmmc_card_t * fatfs::Esp32SdmmcIO::getCard ( )

inline

Get pointer to the card structure (for advanced use)

Returns

Pointer to sdmmc_card_t or nullptr if not initialized

getFreqKHz()

uint32_t fatfs::Esp32SdmmcIO::getFreqKHz ( ) const

inline

Get card frequency in kHz.

Returns

Card operating frequency in kHz

isMMC()

bool fatfs::Esp32SdmmcIO::isMMC ( ) const

inline

Check if card is MMC.

Returns

true if MMC card, false if SD card

mount()

FRESULT fatfs::IO::mount ( FatFs &  fs )

inlinevirtualinherited

mount the file system - implementation at end of header to avoid recursive include

Reimplemented in fatfs::MultiIO, and fatfs::RamIO.

totalSectors()

uint64_t fatfs::Esp32SdmmcIO::totalSectors ( ) const

inline

Get the total number of sectors.

Returns

Total sectors (0 if not initialized)

un_mount()

FRESULT fatfs::IO::un_mount ( FatFs &  fs )

inlinevirtualinherited

unmount the file system - implementation at end of header to avoid recursive include

Reimplemented in fatfs::MultiIO.

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The documentation for this class was generated from the following file:

• src/driver/Esp32SdmmcIO.h