ardupilot/libraries/AP_HAL_F4Light/hardware/sd

SD card layer

works via HAL SPI so should be at this level Much faster than old version and supports much more formats

based on:

• Arduino's SD support for STM32F4 (fixed bugs in read() with data size, in open() with "mode==" and so on, twice reduced memory usage and cured Arduinism)
• FatFs SDIO for STM32F1

uses FatFS (c) Chan

formatting from command-line:

mkfs.fat -I -F 12 -M 0xF9 -s 128 /dev/sd*