+Keyboard LEDs & state of keys(Register2)
+ This register hold current state of three LEDs and nine keys.
+ The state of LEDs can be changed by sending Listen command.
+
+ 1514 . . . . . . 7 6 5 . 3 2 1 0
+ | | | | | | | | | | | | | | | +- LED1(NumLock)
+ | | | | | | | | | | | | | | +--- LED2(CapsLock)
+ | | | | | | | | | | | | | +----- LED3(ScrollLock)
+ | | | | | | | | | | +-+-+------- Reserved
+ | | | | | | | | | +------------- ScrollLock
+ | | | | | | | | +--------------- NumLock
+ | | | | | | | +----------------- Apple/Command
+ | | | | | | +------------------- Option
+ | | | | | +--------------------- Shift
+ | | | | +----------------------- Control
+ | | | +------------------------- Reset/Power
+ | | +--------------------------- CapsLock
+ | +----------------------------- Delete
+ +------------------------------- Reserved
+