Storage

SDMMC/SDSPI

SD card frequency on SDMMC/SDSPI interface can be now configured through sdmmc_host_t.max_freq_khz to a specific value, not only SDMMC_FREQ_PROBING (400 kHz), SDMMC_FREQ_DEFAULT (20 MHz), or SDMMC_FREQ_HIGHSPEED (40 MHz). Previously, in case you have specified a custom frequency other than any of the above-mentioned values, the closest lower-or-equal one was selected anyway.

Now, the underlaying drivers calculate the nearest fitting value, given by available frequency dividers instead of an enumeration item selection. This could cause troubles in communication with your SD card without a change of the existing application code.If you encounter such an issue, please, keep trying different frequencies around your desired value unless you find the one working well. To check the frequency value calculated and actually applied, use void sdmmc_card_print_info(FILE* stream, const sdmmc_card_t* card) function.

FatFs

FatFs is now updated to v0.14. As a result, the function signature of f_mkfs() has changed. The new signature is FRESULT f_mkfs (const TCHAR* path, const MKFS_PARM* opt, void* work, UINT len); which uses MKFS_PARM struct as a second argument.

Partition Table

The partition table generator no longer supports misaligned partitions. When generating a partition table, ESP-IDF only accepts partitions with offsets that align to 4 KB. This change only affects generating new partition tables. Reading and writing to already existing partitions remains unchanged.

VFS

The esp_vfs_semihost_register() function signature is changed as follows:

  • The new signature is esp_err_t esp_vfs_semihost_register(const char* base_path);

  • The host_path parameter of the old signature no longer exists. Instead, the OpenOCD command ESP_SEMIHOST_BASEDIR should be used to set the full path on the host.

Function Signature Changes

The following functions now return esp_err_t instead of void or nvs_iterator_t. Previously, when parameters were invalid or when something goes wrong internally, these functions would assert() or return a nullptr. With an esp_err_t returned, you can get better error reporting.

Because the esp_err_t return type changes, the usage patterns of nvs_entry_find() and nvs_entry_next() become different. Both functions now modify iterators via parameters instead of returning an iterator.

The old programming pattern to iterate over an NVS partition was as follows:

nvs_iterator_t it = nvs_entry_find(<nvs_partition_name>, <namespace>, NVS_TYPE_ANY);
while (it != NULL) {
        nvs_entry_info_t info;
        nvs_entry_info(it, &info);
        it = nvs_entry_next(it);
        printf("key '%s', type '%d'", info.key, info.type);
};

The new programming pattern to iterate over an NVS partition is now:

nvs_iterator_t it = nullptr;
esp_err_t res = nvs_entry_find(<nvs_partition_name>, <namespace>, NVS_TYPE_ANY, &it);
while(res == ESP_OK) {
    nvs_entry_info_t info;
    nvs_entry_info(it, &info); // Can omit error check if parameters are guaranteed to be non-NULL
    printf("key '%s', type '%d'", info.key, info.type);
    res = nvs_entry_next(&it);
}
nvs_release_iterator(it);

Iterator Validity

Note that because the function signature changes, if there is a parameter error, you may get an invalid iterator from nvs_entry_find(). Hence, it is important to initialize the iterator to NULL before using nvs_entry_find(), so that you can avoid complex error checking before calling nvs_release_iterator(). A good example is the programming pattern above.

Removed SDSPI Deprecated API

Structure sdspi_slot_config_t and function sdspi_host_init_slot() are removed, and replaced by structure sdspi_device_config_t and function sdspi_host_init_device() respectively.

ROM SPI Flash

In versions before v5.0, ROM SPI flash functions were included via esp32**/rom/spi_flash.h. Thus, code written to support different ESP chips might be filled with ROM headers of different targets. Furthermore, not all of the APIs could be used on all ESP chips.

Now, the common APIs are extracted to esp_rom_spiflash.h. Although it is not a breaking change, you are strongly recommended to only use the functions from this header (i.e., prefixed with esp_rom_spiflash and included by esp_rom_spiflash.h) for better cross-compatibility between ESP chips.

To make ROM SPI flash APIs clearer, the following functions are also renamed:

  • esp_rom_spiflash_lock() to esp_rom_spiflash_set_bp()

  • esp_rom_spiflash_unlock() to esp_rom_spiflash_clear_bp()

SPI Flash Driver

The esp_flash_speed_t enum type is now deprecated. Instead, you may now directly pass the real clock frequency value to the flash configuration structure. The following example demonstrates how to configure a flash frequency of 80MHz:

esp_flash_spi_device_config_t dev_cfg = {
    // Other members
    .freq_mhz = 80,
    // Other members
};

Legacy SPI Flash Driver

To make SPI flash drivers more stable, the legacy SPI flash driver is removed from v5.0. The legacy SPI flash driver refers to default spi_flash driver since v3.0, and the SPI flash driver with configuration option CONFIG_SPI_FLASH_USE_LEGACY_IMPL enabled since v4.0. The major breaking change here is that the legacy spi_flash driver is no longer supported from v5.0. Therefore, the legacy driver APIs and the CONFIG_SPI_FLASH_USE_LEGACY_IMPL configuration option are both removed. Please use the new spi_flash driver’s APIs instead.

Removed items

Replacement

spi_flash_erase_sector()

esp_flash_erase_region()

spi_flash_erase_range()

esp_flash_erase_region()

spi_flash_write()

esp_flash_write()

spi_flash_read()

esp_flash_read()

spi_flash_write_encrypted()

esp_flash_write_encrypted()

spi_flash_read_encrypted()

esp_flash_read_encrypted()

Note

New functions with prefix esp_flash accept an additional esp_flash_t* parameter. You can simply set it to NULL. This will make the function to run the main flash (esp_flash_default_chip).

The esp_spi_flash.h header is deprecated as system functions are no longer public. To use flash memory mapping APIs, you may include spi_flash_mmap.h instead.