This is a port of ChaN Petit FatFS SD library targeted to low RAM microcontrollers and offers a minimal FAT implementation, with limited write support. For more details see http://elm-chan.org/fsw/ff/00index_p.html
A lot of credits goes to the main contributors to this topic http://forum.43oh.com/topic/1427-petitefs-fatfs-sdcard-usci-code/
Because this library makes use of the SPI library included in Energia it works for both MSP430 and Stellaris launchpads.
With MSP430 I noticed some interference with Serial.print so before every call to the fat library I had to add a small delay. On Stellaris board these are not necessary.
Unzip and copy in Energia\hardware\msp430\libraries or Energia\hardware\lm4f\libraries .
[uPDATE] See post #15 http://forum.43oh.com/topic/3209-energia-library-petit-fatfs-sd-card-library/#entry30031