# Wear levelling example This example demonstrates how to use wear levelling library and FATFS library to store files in a partition inside SPI flash. Example does the following steps: 1. Use an "all-in-one" `esp_vfs_fat_spiflash_mount` function to: - find a partition in SPI flash, - initialize wear levelling library using this partition - mount FAT filesystem using FATFS library (and format the filesystem, if the filesystem can not be mounted), - register FAT filesystem in VFS, enabling C standard library and POSIX functions to be used. 2. Create a file using `fopen` and write to it using `fprintf`. 3. Open file for reading, read back the line, and print it to the terminal. ## Example output Here is an typical example console output. ``` I (280) example: Mounting FAT filesystem W (440) vfs_fat_spiflash: f_mount failed (13) I (440) vfs_fat_spiflash: Formatting FATFS partition, allocation unit size=4096 I (660) vfs_fat_spiflash: Mounting again I (660) example: Opening file I (910) example: File written I (910) example: Reading file I (920) example: Read from file: 'written using ESP-IDF v3.1-dev-171-gf9ad17eee-dirty' I (920) example: Unmounting FAT filesystem I (1000) example: Done ```