xt_usb: read data on falling edge soft/hard reset

See https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-XT-Keyboard-Protocol
- read data on falling edge of clock
- add soft reset and hard reset

converter/xt_usb/Makefile

@@ -11,7 +11,9 @@ TMK_DIR = ../../tmk_core
 TARGET_DIR = .
 
 # project specific files
-SRC =	matrix.c \
+SRC =	protocol/xt_interrupt.c \
+	protocol/xt_io_avr.c \
+	matrix.c \
 	led.c
 
 ifdef KEYMAP
@@ -61,7 +63,7 @@ ARCH = AVR8
 F_USB = $(F_CPU)
 
 # Interrupt driven control endpoint task(+60)
-#OPT_DEFS += -DINTERRUPT_CONTROL_ENDPOINT
+OPT_DEFS += -DINTERRUPT_CONTROL_ENDPOINT
 
 
 # Boot Section Size in *bytes*
@@ -71,6 +73,7 @@ F_USB = $(F_CPU)
 #   LUFA bootloader  4096
 #   USBaspLoader     2048
 OPT_DEFS += -DBOOTLOADER_SIZE=512
+#OPT_DEFS += -DBOOTLOADER_SIZE=4096
 
 
 # Build Options
@@ -84,11 +87,6 @@ COMMAND_ENABLE = yes    # Commands for debug and configuration
 NKRO_ENABLE = yes	# USB Nkey Rollover
 
 
-# XT/2 Options
-#
-XT_USE_INT = yes	# uses external interrupt for falling edge of PS/2 clock pin
-
-
 # Optimize size but this may cause error "relocation truncated to fit"
 #EXTRALDFLAGS = -Wl,--relax