FAT test
fat32 test2
fat32 test3
fat32 test4
fat32 test5
fat32 test6
fat32 test6
fat32 test6
fat32 test
fat32 test
pwm test
fat32 test
config PLL clock to 84MHZ and complete pwm for sample rate 42000HZ sin wave
fat32 via spi can read and write txt
add mount command
add unmount command
prepare to merge
Merge branch 'fat'

Conflicts:
	Makefile
	src/shell.c