Petit FAT File System Module

Petit FatFs is a sub-set of FatFs module for tiny 8-bit microcontrollers. It is written in compliance with ANSI C and completely separated from the disk I/O layer. It can be incorporated into the tiny microcontrollers with limited memory even if the RAM size is less than sector size. Also full featured FAT file system module is available here.

Features

Very Small RAM Consumption (44 Bytes Work Area + Certain Stack).
Very Small Code Size (2K-4K bytes).
FAT12, FAT16 and FAT32.
Single Volume and Single File.
Streaming File Read.
File Write Function with Some Restrictions.

Application Interface

Petit FatFs module provides following functions.

pf_mount - Mount a Volume
pf_open - Open a File
pf_read - Read File
pf_write - Write File
pf_lseek - Move read/write Pointer
pf_opendir - Open a Directory
pf_readdir - Read a Directory Item

Disk I/O Interface

Since the Petit FatFs module is completely separated from disk I/O layer, it requires following functions to lower layer to read data from storage device. The low level disk I/O module is not a part of Petit FatFs module and it must be provided by user. The sample drivers are also available in the resources.

disk_initialize - Initialize storage device
disk_readp - Read a partial sector
disk_writep - Divided write to a sector

Resources

The Petit FatFs module is a free software and is opened for education, research and development. You can use, modify and/or redistribute it for personal, non-profit or commercial use without any restriction under your responsibility. For further information, refer to the application note.

Read first: Petit FatFs module application note January 30, 2019
Download: Petit FatFs R0.03a | Updates | Patches May 20, 2021
Download: Sample projects for various platforms January 30, 2019
Download: Previous Releases
Community: FatFs User Forum
FAT32 Specification by Microsoft↗ (The reference document on FAT file system)
How to Use MMC/SDC
Benchmark 3 (ATtiny85/8MHz with MMC via USI)