This directory contains the ChibiOS/RT "official" bindings with the lwIP TCP/IP stack: http://savannah.nongnu.org/projects/lwip In order to use FatFS within ChibiOS/RT project, unzip FatFS under ./ext/lwip-1.4.0 then include $(CHIBIOS)/os/various/lwip_bindings/lwip.mk in your makefile.