esp-idf/examples/storage/fatfs/bdl_wl

Supported Targets	ESP32	ESP32-C2	ESP32-C3	ESP32-C5	ESP32-C6	ESP32-C61	ESP32-H2	ESP32-H21	ESP32-H4	ESP32-P4	ESP32-S2	ESP32-S3	ESP32-S31

FatFS over BDL (Block Device Layer) - Wear-Levelling Stack

This example demonstrates mounting a FAT filesystem using the Block Device Layer (BDL) interface instead of the legacy wl_handle_t-based API.

BDL Stack

The BDL stack constructed in this example:

  FatFS (VFS + POSIX API)
       |
  diskio_bdl    (generic BDL diskio adapter)
       |
  WL BDL        (wear-levelling, via wl_get_blockdev())
       |
  Partition BDL (flash partition, via esp_partition_get_blockdev())
       |
  SPI Flash     (physical storage)

The key advantage of BDL is that the same diskio_bdl adapter works with any BDL device. You can swap the bottom of the stack (e.g., use sdmmc_get_blockdev() for an SD card) without changing the FatFS integration code.

How to use example

Build and flash

idf.py -p PORT flash monitor

(To exit the serial monitor, type Ctrl-].)

Example output

I (321) example: Creating partition BDL for 'storage' partition
I (331) example:   Partition BDL: disk_size=1048576, erase_size=4096
I (331) example: Creating WL BDL on top of partition BDL
I (341) example:   WL BDL: disk_size=...., erase_size=4096
I (341) example: Mounting FAT filesystem via BDL
I (741) example: Filesystem mounted
I (741) example: Opening file
I (841) example: File written
I (841) example: Reading file
I (841) example: Read from file: 'Hello from FatFS over BDL!'
I (841) example: Unmounting FAT filesystem
I (941) example: Releasing BDL devices
I (941) example: Done