Updated FAQ (markdown)

FAQ.md

@@ -170,3 +170,11 @@ http://deskthority.net/workshop-f7/tmk-keyboard-firmware-collection-t4478-60.htm
 In Windows check `Allow this device to wake the computer` setting in Power **Management property** tab of **Device Manager**. Also check BIOS setting.
 
 Pressing any key during sleep should wake host.
+
+
+## Using Arduino?
+**Note that Arduino pin naming is different from actual chip.** For example, Arduino pin `D0` is not `PD0`. Check circuit with its schematics yourself.
+http://arduino.cc/en/uploads/Main/arduino-leonardo-schematic_3b.pdf
+http://arduino.cc/en/uploads/Main/arduino-micro-schematic.pdf
+
+Arduino leonardo and micro have ATMega32U4 and can be used for TMK, though Arduino bootloader may be a problem.