Open Source FAT File System

M3S-TFAT-Tiny (TFAT) is a FAT file system that only requires a small amount of memory.


Renesas has a robust portfolio of MCUs, including the V850 Family, which are suitable for use in applications such as single-function home appliances and compact industrial equipment, where the incorporation of more sophisticated functionality or the newest technology, with a negligible increase in cost, is desired. To support such development activities, Renesas offers software libraries with only the essential features for application, at low cost.

Use TFAT in any device incorporating a target microcontroller for functions such as accumulating measured or archived data, or rewriting a stored program via memory card. Although TFAT is a FAT file system, and PC data exchange capability enable analysis and management of data by a PC application.

TFAT supports various types of memory devices. The supplied sample programs include sample software for reading/writing files to MultiMediaCard on the CPU board which comes with the Renesas Starter Kit. It also allows you to read/write files to SD Memory Card and USB Flash drive.

Release Information

Target Device Software Name Version/Release date Status
SH-2A M3S-TFAT-Tiny for the SH-2A Latest Version: V.2.00 Release01
Released: December 20, 2013
V850 M3S-TFAT-Tiny for the V850 Family Latest Version: V.2.00 Release01
Released: December 20, 2013

Upgrade Details

Operating Environment

Related Application Notes

*The Application Notes and Sample Code of TFAT for the MCUs are available. Please download from the Sample Code tab for this page.


  • Compact design tailored for embedded systems
  • Realizable using the internal memory of the microcontroller
  • Approx. 5.8KB ROM and approx. 900B RAM (for the RX Family)
  • OS is unnecessary


  • File system software (binary format library)
  • Sample program that supports Renesas integrated development environment.
  • Library function user's manual and other documents in a complete set

Modular Composition

Modular Composition



Function name



Mounts a volume


Opens a file


Closes a file


Reads from a file


Writes to a file


Moves the file pointer


Truncates a file


Flushes the cache


Opens a directory


Reads a directory


Gets free area


Gets file status


Makes a directory


Deletes a file or a directory


Changes properties of a file or a directory


Changes time property of a file or a directory


Renames or moves a file or a directory


Initializes a drive (Note1)


Reads from a drive (Note1)


Writes to a drive (Note1)


Controls drive I/O (Note1)


Gets drive status (Note1)


Gets date and time


The functions need to be created on the customer side as suitable for the hardware used. The TFAT library is not designed for use with a specific piece of hardware and therefore does not include these functions (drivers).



Operating Environment

M3S-TFAT-Tiny for the SH-2A

Target Device SH-2A
Applicable Compiler C/C++ Compiler Package for SuperH Family V.9.04 Release 01 or later
Occupied ROM Size Approx. 8.4KB
Occupied RAM Size Approx. 0.5KB *including the stack

M3S-TFAT-Tiny for the V850 Family

Target Device V850 Family
IDE CubeSuite+ V1.01.01 or later
Applicable Compiler CubeSuite+ V850 compiler CX V1.21 or later
Occupied ROM Size Approx. 8.5KB
Occupied RAM Size Approx. 0.3KB *including the stack




Examples of application field:

  • Data preservation and data logging in various types of equipment
    • Preservation of number of revolutions, temperature and other data in industrial equipment
    • Preservation of a history of operations and settings alteration for remote equipment failure diagnostic
  • Preservation of personal information in health equipment and similar other equipment used individually
    • Preservation of heart rate and blood pressure data in health equipment
    • Preservation of physical exercise data in training equipment
  • Updating of programs and data in various types of equipment
    • Flash memory rewriting with programs or data stored in a memory card in places where equipment is installed

Development Tools Support

Title Description
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e-learning Information for studying and learning about microcontrollers and microprocessors.
FAQ Frequently asked questions and useful hints for development.
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Tool News Tool release information and other important information.
Operating Environment Information on system requirements and operating environment for the latest version of the tools.
Information on Discontinued Products A list of Renesas software and tools that have been discontinued and are no longer being offered for new projects.
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