add initial files from teensy's usb_keyboard_debug.

6 files changed, 1782 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000000..26403c75ad
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,614 @@
+# Hey Emacs, this is a -*- makefile -*-
+#----------------------------------------------------------------------------
+# WinAVR Makefile Template written by Eric B. Weddington, Jörg Wunsch, et al.
+#
+# Released to the Public Domain
+#
+# Additional material for this makefile was written by:
+# Peter Fleury
+# Tim Henigan
+# Colin O'Flynn
+# Reiner Patommel
+# Markus Pfaff
+# Sander Pool
+# Frederik Rouleau
+# Carlos Lamas
+#
+#----------------------------------------------------------------------------
+# On command line:
+#
+# make all = Make software.
+#
+# make clean = Clean out built project files.
+#
+# make coff = Convert ELF to AVR COFF.
+#
+# make extcoff = Convert ELF to AVR Extended COFF.
+#
+# make program = Download the hex file to the device, using avrdude.
+#                Please customize the avrdude settings below first!
+#
+# make debug = Start either simulavr or avarice as specified for debugging, 
+#              with avr-gdb or avr-insight as the front end for debugging.
+#
+# make filename.s = Just compile filename.c into the assembler code only.
+#
+# make filename.i = Create a preprocessed source file for use in submitting
+#                   bug reports to the GCC project.
+#
+# To rebuild project do "make clean" then "make all".
+#----------------------------------------------------------------------------
+
+
+# Target file name (without extension).
+TARGET = example
+
+
+# List C source files here. (C dependencies are automatically generated.)
+SRC =	$(TARGET).c \
+	usb_keyboard_debug.c \
+	print.c
+
+
+# MCU name, you MUST set this to match the board you are using
+# type "make clean" after changing this, so all files will be rebuilt
+#MCU = at90usb162       # Teensy 1.0
+MCU = atmega32u4        # Teensy 2.0
+#MCU = at90usb646       # Teensy++ 1.0
+#MCU = at90usb1286      # Teensy++ 2.0
+
+
+# Processor frequency.
+#   Normally the first thing your program should do is set the clock prescaler,
+#   so your program will run at the correct speed.  You should also set this
+#   variable to same clock speed.  The _delay_ms() macro uses this, and many
+#   examples use this variable to calculate timings.  Do not add a "UL" here.
+F_CPU = 16000000
+
+
+# Output format. (can be srec, ihex, binary)
+FORMAT = ihex
+
+
+# Object files directory
+#     To put object files in current directory, use a dot (.), do NOT make
+#     this an empty or blank macro!
+OBJDIR = .
+
+
+# List C++ source files here. (C dependencies are automatically generated.)
+CPPSRC = 
+
+
+# List Assembler source files here.
+#     Make them always end in a capital .S.  Files ending in a lowercase .s
+#     will not be considered source files but generated files (assembler
+#     output from the compiler), and will be deleted upon "make clean"!
+#     Even though the DOS/Win* filesystem matches both .s and .S the same,
+#     it will preserve the spelling of the filenames, and gcc itself does
+#     care about how the name is spelled on its command-line.
+ASRC =
+
+
+# Optimization level, can be [0, 1, 2, 3, s]. 
+#     0 = turn off optimization. s = optimize for size.
+#     (Note: 3 is not always the best optimization level. See avr-libc FAQ.)
+OPT = s
+
+
+# Debugging format.
+#     Native formats for AVR-GCC's -g are dwarf-2 [default] or stabs.
+#     AVR Studio 4.10 requires dwarf-2.
+#     AVR [Extended] COFF format requires stabs, plus an avr-objcopy run.
+DEBUG = dwarf-2
+
+
+# List any extra directories to look for include files here.
+#     Each directory must be seperated by a space.
+#     Use forward slashes for directory separators.
+#     For a directory that has spaces, enclose it in quotes.
+EXTRAINCDIRS = 
+
+
+# Compiler flag to set the C Standard level.
+#     c89   = "ANSI" C
+#     gnu89 = c89 plus GCC extensions
+#     c99   = ISO C99 standard (not yet fully implemented)
+#     gnu99 = c99 plus GCC extensions
+CSTANDARD = -std=gnu99
+
+
+# Place -D or -U options here for C sources
+CDEFS = -DF_CPU=$(F_CPU)UL
+
+
+# Place -D or -U options here for ASM sources
+ADEFS = -DF_CPU=$(F_CPU)
+
+
+# Place -D or -U options here for C++ sources
+CPPDEFS = -DF_CPU=$(F_CPU)UL
+#CPPDEFS += -D__STDC_LIMIT_MACROS
+#CPPDEFS += -D__STDC_CONSTANT_MACROS
+
+
+
+#---------------- Compiler Options C ----------------
+#  -g*:          generate debugging information
+#  -O*:          optimization level
+#  -f...:        tuning, see GCC manual and avr-libc documentation
+#  -Wall...:     warning level
+#  -Wa,...:      tell GCC to pass this to the assembler.
+#    -adhlns...: create assembler listing
+CFLAGS = -g$(DEBUG)
+CFLAGS += $(CDEFS)
+CFLAGS += -O$(OPT)
+CFLAGS += -funsigned-char
+CFLAGS += -funsigned-bitfields
+CFLAGS += -ffunction-sections
+CFLAGS += -fpack-struct
+CFLAGS += -fshort-enums
+CFLAGS += -Wall
+CFLAGS += -Wstrict-prototypes
+#CFLAGS += -mshort-calls
+#CFLAGS += -fno-unit-at-a-time
+#CFLAGS += -Wundef
+#CFLAGS += -Wunreachable-code
+#CFLAGS += -Wsign-compare
+CFLAGS += -Wa,-adhlns=$(<:%.c=$(OBJDIR)/%.lst)
+CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
+CFLAGS += $(CSTANDARD)
+
+
+#---------------- Compiler Options C++ ----------------
+#  -g*:          generate debugging information
+#  -O*:          optimization level
+#  -f...:        tuning, see GCC manual and avr-libc documentation
+#  -Wall...:     warning level
+#  -Wa,...:      tell GCC to pass this to the assembler.
+#    -adhlns...: create assembler listing
+CPPFLAGS = -g$(DEBUG)
+CPPFLAGS += $(CPPDEFS)
+CPPFLAGS += -O$(OPT)
+CPPFLAGS += -funsigned-char
+CPPFLAGS += -funsigned-bitfields
+CPPFLAGS += -fpack-struct
+CPPFLAGS += -fshort-enums
+CPPFLAGS += -fno-exceptions
+CPPFLAGS += -Wall
+CPPFLAGS += -Wundef
+#CPPFLAGS += -mshort-calls
+#CPPFLAGS += -fno-unit-at-a-time
+#CPPFLAGS += -Wstrict-prototypes
+#CPPFLAGS += -Wunreachable-code
+#CPPFLAGS += -Wsign-compare
+CPPFLAGS += -Wa,-adhlns=$(<:%.cpp=$(OBJDIR)/%.lst)
+CPPFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
+#CPPFLAGS += $(CSTANDARD)
+
+
+#---------------- Assembler Options ----------------
+#  -Wa,...:   tell GCC to pass this to the assembler.
+#  -adhlns:   create listing
+#  -gstabs:   have the assembler create line number information; note that
+#             for use in COFF files, additional information about filenames
+#             and function names needs to be present in the assembler source
+#             files -- see avr-libc docs [FIXME: not yet described there]
+#  -listing-cont-lines: Sets the maximum number of continuation lines of hex 
+#       dump that will be displayed for a given single line of source input.
+ASFLAGS = $(ADEFS) -Wa,-adhlns=$(<:%.S=$(OBJDIR)/%.lst),-gstabs,--listing-cont-lines=100
+
+
+#---------------- Library Options ----------------
+# Minimalistic printf version
+PRINTF_LIB_MIN = -Wl,-u,vfprintf -lprintf_min
+
+# Floating point printf version (requires MATH_LIB = -lm below)
+PRINTF_LIB_FLOAT = -Wl,-u,vfprintf -lprintf_flt
+
+# If this is left blank, then it will use the Standard printf version.
+PRINTF_LIB = 
+#PRINTF_LIB = $(PRINTF_LIB_MIN)
+#PRINTF_LIB = $(PRINTF_LIB_FLOAT)
+
+
+# Minimalistic scanf version
+SCANF_LIB_MIN = -Wl,-u,vfscanf -lscanf_min
+
+# Floating point + %[ scanf version (requires MATH_LIB = -lm below)
+SCANF_LIB_FLOAT = -Wl,-u,vfscanf -lscanf_flt
+
+# If this is left blank, then it will use the Standard scanf version.
+SCANF_LIB = 
+#SCANF_LIB = $(SCANF_LIB_MIN)
+#SCANF_LIB = $(SCANF_LIB_FLOAT)
+
+
+MATH_LIB = -lm
+
+
+# List any extra directories to look for libraries here.
+#     Each directory must be seperated by a space.
+#     Use forward slashes for directory separators.
+#     For a directory that has spaces, enclose it in quotes.
+EXTRALIBDIRS = 
+
+
+
+#---------------- External Memory Options ----------------
+
+# 64 KB of external RAM, starting after internal RAM (ATmega128!),
+# used for variables (.data/.bss) and heap (malloc()).
+#EXTMEMOPTS = -Wl,-Tdata=0x801100,--defsym=__heap_end=0x80ffff
+
+# 64 KB of external RAM, starting after internal RAM (ATmega128!),
+# only used for heap (malloc()).
+#EXTMEMOPTS = -Wl,--section-start,.data=0x801100,--defsym=__heap_end=0x80ffff
+
+EXTMEMOPTS =
+
+
+
+#---------------- Linker Options ----------------
+#  -Wl,...:     tell GCC to pass this to linker.
+#    -Map:      create map file
+#    --cref:    add cross reference to  map file
+LDFLAGS = -Wl,-Map=$(TARGET).map,--cref
+LDFLAGS += -Wl,--relax
+LDFLAGS += -Wl,--gc-sections
+LDFLAGS += $(EXTMEMOPTS)
+LDFLAGS += $(patsubst %,-L%,$(EXTRALIBDIRS))
+LDFLAGS += $(PRINTF_LIB) $(SCANF_LIB) $(MATH_LIB)
+#LDFLAGS += -T linker_script.x
+
+
+
+#---------------- Programming Options (avrdude) ----------------
+
+# Programming hardware
+# Type: avrdude -c ?
+# to get a full listing.
+#
+AVRDUDE_PROGRAMMER = stk500v2
+
+# com1 = serial port. Use lpt1 to connect to parallel port.
+AVRDUDE_PORT = com1    # programmer connected to serial device
+
+AVRDUDE_WRITE_FLASH = -U flash:w:$(TARGET).hex
+#AVRDUDE_WRITE_EEPROM = -U eeprom:w:$(TARGET).eep
+
+
+# Uncomment the following if you want avrdude's erase cycle counter.
+# Note that this counter needs to be initialized first using -Yn,
+# see avrdude manual.
+#AVRDUDE_ERASE_COUNTER = -y
+
+# Uncomment the following if you do /not/ wish a verification to be
+# performed after programming the device.
+#AVRDUDE_NO_VERIFY = -V
+
+# Increase verbosity level.  Please use this when submitting bug
+# reports about avrdude. See <http://savannah.nongnu.org/projects/avrdude> 
+# to submit bug reports.
+#AVRDUDE_VERBOSE = -v -v
+
+AVRDUDE_FLAGS = -p $(MCU) -P $(AVRDUDE_PORT) -c $(AVRDUDE_PROGRAMMER)
+AVRDUDE_FLAGS += $(AVRDUDE_NO_VERIFY)
+AVRDUDE_FLAGS += $(AVRDUDE_VERBOSE)
+AVRDUDE_FLAGS += $(AVRDUDE_ERASE_COUNTER)
+
+
+
+#---------------- Debugging Options ----------------
+
+# For simulavr only - target MCU frequency.
+DEBUG_MFREQ = $(F_CPU)
+
+# Set the DEBUG_UI to either gdb or insight.
+# DEBUG_UI = gdb
+DEBUG_UI = insight
+
+# Set the debugging back-end to either avarice, simulavr.
+DEBUG_BACKEND = avarice
+#DEBUG_BACKEND = simulavr
+
+# GDB Init Filename.
+GDBINIT_FILE = __avr_gdbinit
+
+# When using avarice settings for the JTAG
+JTAG_DEV = /dev/com1
+
+# Debugging port used to communicate between GDB / avarice / simulavr.
+DEBUG_PORT = 4242
+
+# Debugging host used to communicate between GDB / avarice / simulavr, normally
+#     just set to localhost unless doing some sort of crazy debugging when 
+#     avarice is running on a different computer.
+DEBUG_HOST = localhost
+
+
+
+#============================================================================
+
+
+# Define programs and commands.
+SHELL = sh
+CC = avr-gcc
+OBJCOPY = avr-objcopy
+OBJDUMP = avr-objdump
+SIZE = avr-size
+AR = avr-ar rcs
+NM = avr-nm
+AVRDUDE = avrdude
+REMOVE = rm -f
+REMOVEDIR = rm -rf
+COPY = cp
+WINSHELL = cmd
+
+
+# Define Messages
+# English
+MSG_ERRORS_NONE = Errors: none
+MSG_BEGIN = -------- begin --------
+MSG_END = --------  end  --------
+MSG_SIZE_BEFORE = Size before: 
+MSG_SIZE_AFTER = Size after:
+MSG_COFF = Converting to AVR COFF:
+MSG_EXTENDED_COFF = Converting to AVR Extended COFF:
+MSG_FLASH = Creating load file for Flash:
+MSG_EEPROM = Creating load file for EEPROM:
+MSG_EXTENDED_LISTING = Creating Extended Listing:
+MSG_SYMBOL_TABLE = Creating Symbol Table:
+MSG_LINKING = Linking:
+MSG_COMPILING = Compiling C:
+MSG_COMPILING_CPP = Compiling C++:
+MSG_ASSEMBLING = Assembling:
+MSG_CLEANING = Cleaning project:
+MSG_CREATING_LIBRARY = Creating library:
+
+
+
+
+# Define all object files.
+OBJ = $(SRC:%.c=$(OBJDIR)/%.o) $(CPPSRC:%.cpp=$(OBJDIR)/%.o) $(ASRC:%.S=$(OBJDIR)/%.o) 
+
+# Define all listing files.
+LST = $(SRC:%.c=$(OBJDIR)/%.lst) $(CPPSRC:%.cpp=$(OBJDIR)/%.lst) $(ASRC:%.S=$(OBJDIR)/%.lst) 
+
+
+# Compiler flags to generate dependency files.
+GENDEPFLAGS = -MMD -MP -MF .dep/$(@F).d
+
+
+# Combine all necessary flags and optional flags.
+# Add target processor to flags.
+ALL_CFLAGS = -mmcu=$(MCU) -I. $(CFLAGS) $(GENDEPFLAGS)
+ALL_CPPFLAGS = -mmcu=$(MCU) -I. -x c++ $(CPPFLAGS) $(GENDEPFLAGS)
+ALL_ASFLAGS = -mmcu=$(MCU) -I. -x assembler-with-cpp $(ASFLAGS)
+
+
+
+
+
+# Default target.
+all: begin gccversion sizebefore build sizeafter end
+
+# Change the build target to build a HEX file or a library.
+build: elf hex eep lss sym
+#build: lib
+
+
+elf: $(TARGET).elf
+hex: $(TARGET).hex
+eep: $(TARGET).eep
+lss: $(TARGET).lss
+sym: $(TARGET).sym
+LIBNAME=lib$(TARGET).a
+lib: $(LIBNAME)
+
+
+
+# Eye candy.
+# AVR Studio 3.x does not check make's exit code but relies on
+# the following magic strings to be generated by the compile job.
+begin:
+	@echo
+	@echo $(MSG_BEGIN)
+
+end:
+	@echo $(MSG_END)
+	@echo
+
+
+# Display size of file.
+HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex
+#ELFSIZE = $(SIZE) --mcu=$(MCU) --format=avr $(TARGET).elf
+ELFSIZE = $(SIZE) $(TARGET).elf
+
+sizebefore:
+	@if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_BEFORE); $(ELFSIZE); \
+	2>/dev/null; echo; fi
+
+sizeafter:
+	@if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_AFTER); $(ELFSIZE); \
+	2>/dev/null; echo; fi
+
+
+
+# Display compiler version information.
+gccversion : 
+	@$(CC) --version
+
+
+
+# Program the device.  
+program: $(TARGET).hex $(TARGET).eep
+	$(AVRDUDE) $(AVRDUDE_FLAGS) $(AVRDUDE_WRITE_FLASH) $(AVRDUDE_WRITE_EEPROM)
+
+
+# Generate avr-gdb config/init file which does the following:
+#     define the reset signal, load the target file, connect to target, and set 
+#     a breakpoint at main().
+gdb-config: 
+	@$(REMOVE) $(GDBINIT_FILE)
+	@echo define reset >> $(GDBINIT_FILE)
+	@echo SIGNAL SIGHUP >> $(GDBINIT_FILE)
+	@echo end >> $(GDBINIT_FILE)
+	@echo file $(TARGET).elf >> $(GDBINIT_FILE)
+	@echo target remote $(DEBUG_HOST):$(DEBUG_PORT)  >> $(GDBINIT_FILE)
+ifeq ($(DEBUG_BACKEND),simulavr)
+	@echo load  >> $(GDBINIT_FILE)
+endif
+	@echo break main >> $(GDBINIT_FILE)
+
+debug: gdb-config $(TARGET).elf
+ifeq ($(DEBUG_BACKEND), avarice)
+	@echo Starting AVaRICE - Press enter when "waiting to connect" message displays.
+	@$(WINSHELL) /c start avarice --jtag $(JTAG_DEV) --erase --program --file \
+	$(TARGET).elf $(DEBUG_HOST):$(DEBUG_PORT)
+	@$(WINSHELL) /c pause
+
+else
+	@$(WINSHELL) /c start simulavr --gdbserver --device $(MCU) --clock-freq \
+	$(DEBUG_MFREQ) --port $(DEBUG_PORT)
+endif
+	@$(WINSHELL) /c start avr-$(DEBUG_UI) --command=$(GDBINIT_FILE)
+
+
+
+
+# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB.
+COFFCONVERT = $(OBJCOPY) --debugging
+COFFCONVERT += --change-section-address .data-0x800000
+COFFCONVERT += --change-section-address .bss-0x800000
+COFFCONVERT += --change-section-address .noinit-0x800000
+COFFCONVERT += --change-section-address .eeprom-0x810000
+
+
+
+coff: $(TARGET).elf
+	@echo
+	@echo $(MSG_COFF) $(TARGET).cof
+	$(COFFCONVERT) -O coff-avr $< $(TARGET).cof
+
+
+extcoff: $(TARGET).elf
+	@echo
+	@echo $(MSG_EXTENDED_COFF) $(TARGET).cof
+	$(COFFCONVERT) -O coff-ext-avr $< $(TARGET).cof
+
+
+
+# Create final output files (.hex, .eep) from ELF output file.
+%.hex: %.elf
+	@echo
+	@echo $(MSG_FLASH) $@
+	$(OBJCOPY) -O $(FORMAT) -R .eeprom -R .fuse -R .lock -R .signature $< $@
+
+%.eep: %.elf
+	@echo
+	@echo $(MSG_EEPROM) $@
+	-$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
+	--change-section-lma .eeprom=0 --no-change-warnings -O $(FORMAT) $< $@ || exit 0
+
+# Create extended listing file from ELF output file.
+%.lss: %.elf
+	@echo
+	@echo $(MSG_EXTENDED_LISTING) $@
+	$(OBJDUMP) -h -S -z $< > $@
+
+# Create a symbol table from ELF output file.
+%.sym: %.elf
+	@echo
+	@echo $(MSG_SYMBOL_TABLE) $@
+	$(NM) -n $< > $@
+
+
+
+# Create library from object files.
+.SECONDARY : $(TARGET).a
+.PRECIOUS : $(OBJ)
+%.a: $(OBJ)
+	@echo
+	@echo $(MSG_CREATING_LIBRARY) $@
+	$(AR) $@ $(OBJ)
+
+
+# Link: create ELF output file from object files.
+.SECONDARY : $(TARGET).elf
+.PRECIOUS : $(OBJ)
+%.elf: $(OBJ)
+	@echo
+	@echo $(MSG_LINKING) $@
+	$(CC) $(ALL_CFLAGS) $^ --output $@ $(LDFLAGS)
+
+
+# Compile: create object files from C source files.
+$(OBJDIR)/%.o : %.c
+	@echo
+	@echo $(MSG_COMPILING) $<
+	$(CC) -c $(ALL_CFLAGS) $< -o $@ 
+
+
+# Compile: create object files from C++ source files.
+$(OBJDIR)/%.o : %.cpp
+	@echo
+	@echo $(MSG_COMPILING_CPP) $<
+	$(CC) -c $(ALL_CPPFLAGS) $< -o $@ 
+
+
+# Compile: create assembler files from C source files.
+%.s : %.c
+	$(CC) -S $(ALL_CFLAGS) $< -o $@
+
+
+# Compile: create assembler files from C++ source files.
+%.s : %.cpp
+	$(CC) -S $(ALL_CPPFLAGS) $< -o $@
+
+
+# Assemble: create object files from assembler source files.
+$(OBJDIR)/%.o : %.S
+	@echo
+	@echo $(MSG_ASSEMBLING) $<
+	$(CC) -c $(ALL_ASFLAGS) $< -o $@
+
+
+# Create preprocessed source for use in sending a bug report.
+%.i : %.c
+	$(CC) -E -mmcu=$(MCU) -I. $(CFLAGS) $< -o $@ 
+
+
+# Target: clean project.
+clean: begin clean_list end
+
+clean_list :
+	@echo
+	@echo $(MSG_CLEANING)
+	$(REMOVE) $(TARGET).hex
+	$(REMOVE) $(TARGET).eep
+	$(REMOVE) $(TARGET).cof
+	$(REMOVE) $(TARGET).elf
+	$(REMOVE) $(TARGET).map
+	$(REMOVE) $(TARGET).sym
+	$(REMOVE) $(TARGET).lss
+	$(REMOVE) $(SRC:%.c=$(OBJDIR)/%.o)
+	$(REMOVE) $(SRC:%.c=$(OBJDIR)/%.lst)
+	$(REMOVE) $(SRC:.c=.s)
+	$(REMOVE) $(SRC:.c=.d)
+	$(REMOVE) $(SRC:.c=.i)
+	$(REMOVEDIR) .dep
+
+
+# Create object files directory
+$(shell mkdir $(OBJDIR) 2>/dev/null)
+
+
+# Include the dependency files.
+-include $(shell mkdir .dep 2>/dev/null) $(wildcard .dep/*)
+
+
+# Listing of phony targets.
+.PHONY : all begin finish end sizebefore sizeafter gccversion \
+build elf hex eep lss sym coff extcoff \
+clean clean_list program debug gdb-config
diff --git a/example.c b/example.c
new file mode 100644
index 0000000000..2433794eb7
--- /dev/null
+++ b/example.c
@@ -0,0 +1,137 @@
+/* Keyboard example with debug channel, for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/usb_keyboard.html
+ * Copyright (c) 2008 PJRC.COM, LLC
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+#include "usb_keyboard_debug.h"
+#include "print.h"
+
+#define LED_CONFIG	(DDRD |= (1<<6))
+#define LED_ON		(PORTD &= ~(1<<6))
+#define LED_OFF		(PORTD |= (1<<6))
+#define CPU_PRESCALE(n)	(CLKPR = 0x80, CLKPR = (n))
+
+uint8_t number_keys[10]=
+	{KEY_0,KEY_1,KEY_2,KEY_3,KEY_4,KEY_5,KEY_6,KEY_7,KEY_8,KEY_9};
+
+uint16_t idle_count=0;
+
+int main(void)
+{
+	uint8_t b, d, mask, i, reset_idle;
+	uint8_t b_prev=0xFF, d_prev=0xFF;
+
+	// set for 16 MHz clock
+	CPU_PRESCALE(0);
+
+	// Configure all port B and port D pins as inputs with pullup resistors.
+	// See the "Using I/O Pins" page for details.
+	// http://www.pjrc.com/teensy/pins.html
+	DDRD = 0x00;
+	DDRB = 0x00;
+	PORTB = 0xFF;
+	PORTD = 0xFF;
+
+	// Initialize the USB, and then wait for the host to set configuration.
+	// If the Teensy is powered without a PC connected to the USB port,
+	// this will wait forever.
+	usb_init();
+	while (!usb_configured()) /* wait */ ;
+
+	// Wait an extra second for the PC's operating system to load drivers
+	// and do whatever it does to actually be ready for input
+	_delay_ms(1000);
+
+	// Configure timer 0 to generate a timer overflow interrupt every
+	// 256*1024 clock cycles, or approx 61 Hz when using 16 MHz clock
+	// This demonstrates how to use interrupts to implement a simple
+	// inactivity timeout.
+	TCCR0A = 0x00;
+	TCCR0B = 0x05;
+	TIMSK0 = (1<<TOIE0);
+
+	print("Begin keyboard example program\n");
+	print("All Port B or Port D pins are inputs with pullup resistors.\n");
+	print("Any connection to ground on Port B or D pins will result in\n");
+	print("keystrokes sent to the PC (and debug messages here).\n");
+	while (1) {
+		// read all port B and port D pins
+		b = PINB;
+		d = PIND;
+		// check if any pins are low, but were high previously
+		mask = 1;
+		reset_idle = 0;
+		for (i=0; i<8; i++) {
+			if (((b & mask) == 0) && (b_prev & mask) != 0) {
+				usb_keyboard_press(KEY_B, KEY_SHIFT);
+				usb_keyboard_press(number_keys[i], 0);
+				print("Port B, bit ");
+				phex(i);
+				print("\n");
+				reset_idle = 1;
+			}
+			if (((d & mask) == 0) && (d_prev & mask) != 0) {
+				usb_keyboard_press(KEY_D, KEY_SHIFT);
+				usb_keyboard_press(number_keys[i], 0);
+				print("Port D, bit ");
+				phex(i);
+				print("\n");
+				reset_idle = 1;
+			}
+			mask = mask << 1;
+		}
+		// if any keypresses were detected, reset the idle counter
+		if (reset_idle) {
+			// variables shared with interrupt routines must be
+			// accessed carefully so the interrupt routine doesn't
+			// try to use the variable in the middle of our access
+			cli();
+			idle_count = 0;
+			sei();
+		}
+		// now the current pins will be the previous, and
+		// wait a short delay so we're not highly sensitive
+		// to mechanical "bounce".
+		b_prev = b;
+		d_prev = d;
+		_delay_ms(2);
+	}
+}
+
+// This interrupt routine is run approx 61 times per second.
+// A very simple inactivity timeout is implemented, where we
+// will send a space character and print a message to the
+// hid_listen debug message window.
+ISR(TIMER0_OVF_vect)
+{
+	idle_count++;
+	if (idle_count > 61 * 8) {
+		idle_count = 0;
+		print("Timer Event :)\n");
+		usb_keyboard_press(KEY_SPACE, 0);
+	}
+}
+
+
diff --git a/print.c b/print.c
new file mode 100644
index 0000000000..e6aa1fe52b
--- /dev/null
+++ b/print.c
@@ -0,0 +1,62 @@
+/* Very basic print functions, intended to be used with usb_debug_only.c
+ * http://www.pjrc.com/teensy/
+ * Copyright (c) 2008 PJRC.COM, LLC
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// Version 1.0: Initial Release
+
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+
+#include "print.h"
+
+void print_P(const char *s)
+{
+	char c;
+
+	while (1) {
+		c = pgm_read_byte(s++);
+		if (!c) break;
+		if (c == '\n') usb_debug_putchar('\r');
+		usb_debug_putchar(c);
+	}
+}
+
+void phex1(unsigned char c)
+{
+	usb_debug_putchar(c + ((c < 10) ? '0' : 'A' - 10));
+}
+
+void phex(unsigned char c)
+{
+	phex1(c >> 4);
+	phex1(c & 15);
+}
+
+void phex16(unsigned int i)
+{
+	phex(i >> 8);
+	phex(i);
+}
+
+
+
+
diff --git a/print.h b/print.h
new file mode 100644
index 0000000000..1de618fbaa
--- /dev/null
+++ b/print.h
@@ -0,0 +1,16 @@
+#ifndef print_h__
+#define print_h__
+
+#include <avr/pgmspace.h>
+#include "usb_keyboard_debug.h"
+
+// this macro allows you to write print("some text") and
+// the string is automatically placed into flash memory :)
+#define print(s) print_P(PSTR(s))
+#define pchar(c) usb_debug_putchar(c)
+
+void print_P(const char *s);
+void phex(unsigned char c);
+void phex16(unsigned int i);
+
+#endif
diff --git a/usb_keyboard_debug.c b/usb_keyboard_debug.c
new file mode 100644
index 0000000000..9bab25e905
--- /dev/null
+++ b/usb_keyboard_debug.c
@@ -0,0 +1,750 @@
+/* USB Keyboard Plus Debug Channel Example for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/usb_keyboard.html
+ * Copyright (c) 2009 PJRC.COM, LLC
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// Version 1.0: Initial Release
+// Version 1.1: Add support for Teensy 2.0
+
+#define USB_SERIAL_PRIVATE_INCLUDE
+#include "usb_keyboard_debug.h"
+
+/**************************************************************************
+ *
+ *  Configurable Options
+ *
+ **************************************************************************/
+
+// You can change these to give your code its own name.
+#define STR_MANUFACTURER	L"MfgName"
+#define STR_PRODUCT		L"Keyboard"
+
+
+// Mac OS-X and Linux automatically load the correct drivers.  On
+// Windows, even though the driver is supplied by Microsoft, an
+// INF file is needed to load the driver.  These numbers need to
+// match the INF file.
+#define VENDOR_ID		0x16C0
+#define PRODUCT_ID		0x047D
+
+
+// USB devices are supposed to implment a halt feature, which is
+// rarely (if ever) used.  If you comment this line out, the halt
+// code will be removed, saving 102 bytes of space (gcc 4.3.0).
+// This is not strictly USB compliant, but works with all major
+// operating systems.
+#define SUPPORT_ENDPOINT_HALT
+
+
+
+/**************************************************************************
+ *
+ *  Endpoint Buffer Configuration
+ *
+ **************************************************************************/
+
+#define ENDPOINT0_SIZE		32
+
+#define KEYBOARD_INTERFACE	0
+#define KEYBOARD_ENDPOINT	3
+#define KEYBOARD_SIZE		8
+#define KEYBOARD_BUFFER		EP_DOUBLE_BUFFER
+
+#define DEBUG_INTERFACE		1
+#define DEBUG_TX_ENDPOINT	4
+#define DEBUG_TX_SIZE		32
+#define DEBUG_TX_BUFFER		EP_DOUBLE_BUFFER
+
+static const uint8_t PROGMEM endpoint_config_table[] = {
+	0,
+	0,
+	1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(KEYBOARD_SIZE) | KEYBOARD_BUFFER,
+	1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(DEBUG_TX_SIZE) | DEBUG_TX_BUFFER
+};
+
+
+/**************************************************************************
+ *
+ *  Descriptor Data
+ *
+ **************************************************************************/
+
+// Descriptors are the data that your computer reads when it auto-detects
+// this USB device (called "enumeration" in USB lingo).  The most commonly
+// changed items are editable at the top of this file.  Changing things
+// in here should only be done by those who've read chapter 9 of the USB
+// spec and relevant portions of any USB class specifications!
+
+
+static uint8_t PROGMEM device_descriptor[] = {
+	18,					// bLength
+	1,					// bDescriptorType
+	0x00, 0x02,				// bcdUSB
+	0,					// bDeviceClass
+	0,					// bDeviceSubClass
+	0,					// bDeviceProtocol
+	ENDPOINT0_SIZE,				// bMaxPacketSize0
+	LSB(VENDOR_ID), MSB(VENDOR_ID),		// idVendor
+	LSB(PRODUCT_ID), MSB(PRODUCT_ID),	// idProduct
+	0x00, 0x01,				// bcdDevice
+	1,					// iManufacturer
+	2,					// iProduct
+	0,					// iSerialNumber
+	1					// bNumConfigurations
+};
+
+// Keyboard Protocol 1, HID 1.11 spec, Appendix B, page 59-60
+static uint8_t PROGMEM keyboard_hid_report_desc[] = {
+        0x05, 0x01,          // Usage Page (Generic Desktop),
+        0x09, 0x06,          // Usage (Keyboard),
+        0xA1, 0x01,          // Collection (Application),
+        0x75, 0x01,          //   Report Size (1),
+        0x95, 0x08,          //   Report Count (8),
+        0x05, 0x07,          //   Usage Page (Key Codes),
+        0x19, 0xE0,          //   Usage Minimum (224),
+        0x29, 0xE7,          //   Usage Maximum (231),
+        0x15, 0x00,          //   Logical Minimum (0),
+        0x25, 0x01,          //   Logical Maximum (1),
+        0x81, 0x02,          //   Input (Data, Variable, Absolute), ;Modifier byte
+        0x95, 0x01,          //   Report Count (1),
+        0x75, 0x08,          //   Report Size (8),
+        0x81, 0x03,          //   Input (Constant),                 ;Reserved byte
+        0x95, 0x05,          //   Report Count (5),
+        0x75, 0x01,          //   Report Size (1),
+        0x05, 0x08,          //   Usage Page (LEDs),
+        0x19, 0x01,          //   Usage Minimum (1),
+        0x29, 0x05,          //   Usage Maximum (5),
+        0x91, 0x02,          //   Output (Data, Variable, Absolute), ;LED report
+        0x95, 0x01,          //   Report Count (1),
+        0x75, 0x03,          //   Report Size (3),
+        0x91, 0x03,          //   Output (Constant),                 ;LED report padding
+        0x95, 0x06,          //   Report Count (6),
+        0x75, 0x08,          //   Report Size (8),
+        0x15, 0x00,          //   Logical Minimum (0),
+        0x25, 0x68,          //   Logical Maximum(104),
+        0x05, 0x07,          //   Usage Page (Key Codes),
+        0x19, 0x00,          //   Usage Minimum (0),
+        0x29, 0x68,          //   Usage Maximum (104),
+        0x81, 0x00,          //   Input (Data, Array),
+        0xc0                 // End Collection
+};
+
+static uint8_t PROGMEM debug_hid_report_desc[] = {
+	0x06, 0x31, 0xFF,			// Usage Page 0xFF31 (vendor defined)
+	0x09, 0x74,				// Usage 0x74
+	0xA1, 0x53,				// Collection 0x53
+	0x75, 0x08,				// report size = 8 bits
+	0x15, 0x00,				// logical minimum = 0
+	0x26, 0xFF, 0x00,			// logical maximum = 255
+	0x95, DEBUG_TX_SIZE,			// report count
+	0x09, 0x75,				// usage
+	0x81, 0x02,				// Input (array)
+	0xC0					// end collection
+};
+
+#define CONFIG1_DESC_SIZE        (9+9+9+7+9+9+7)
+#define KEYBOARD_HID_DESC_OFFSET (9+9)
+#define DEBUG_HID_DESC_OFFSET    (9+9+9+7+9)
+static uint8_t PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
+	// configuration descriptor, USB spec 9.6.3, page 264-266, Table 9-10
+	9, 					// bLength;
+	2,					// bDescriptorType;
+	LSB(CONFIG1_DESC_SIZE),			// wTotalLength
+	MSB(CONFIG1_DESC_SIZE),
+	2,					// bNumInterfaces
+	1,					// bConfigurationValue
+	0,					// iConfiguration
+	0xC0,					// bmAttributes
+	50,					// bMaxPower
+	// interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
+	9,					// bLength
+	4,					// bDescriptorType
+	KEYBOARD_INTERFACE,			// bInterfaceNumber
+	0,					// bAlternateSetting
+	1,					// bNumEndpoints
+	0x03,					// bInterfaceClass (0x03 = HID)
+	0x01,					// bInterfaceSubClass (0x01 = Boot)
+	0x01,					// bInterfaceProtocol (0x01 = Keyboard)
+	0,					// iInterface
+	// HID interface descriptor, HID 1.11 spec, section 6.2.1
+	9,					// bLength
+	0x21,					// bDescriptorType
+	0x11, 0x01,				// bcdHID
+	0,					// bCountryCode
+	1,					// bNumDescriptors
+	0x22,					// bDescriptorType
+	sizeof(keyboard_hid_report_desc),	// wDescriptorLength
+	0,
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	KEYBOARD_ENDPOINT | 0x80,		// bEndpointAddress
+	0x03,					// bmAttributes (0x03=intr)
+	KEYBOARD_SIZE, 0,			// wMaxPacketSize
+	1,					// bInterval
+	// interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
+	9,					// bLength
+	4,					// bDescriptorType
+	DEBUG_INTERFACE,			// bInterfaceNumber
+	0,					// bAlternateSetting
+	1,					// bNumEndpoints
+	0x03,					// bInterfaceClass (0x03 = HID)
+	0x00,					// bInterfaceSubClass
+	0x00,					// bInterfaceProtocol
+	0,					// iInterface
+	// HID interface descriptor, HID 1.11 spec, section 6.2.1
+	9,					// bLength
+	0x21,					// bDescriptorType
+	0x11, 0x01,				// bcdHID
+	0,					// bCountryCode
+	1,					// bNumDescriptors
+	0x22,					// bDescriptorType
+	sizeof(debug_hid_report_desc),		// wDescriptorLength
+	0,
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	DEBUG_TX_ENDPOINT | 0x80,		// bEndpointAddress
+	0x03,					// bmAttributes (0x03=intr)
+	DEBUG_TX_SIZE, 0,			// wMaxPacketSize
+	1					// bInterval
+};
+
+// If you're desperate for a little extra code memory, these strings
+// can be completely removed if iManufacturer, iProduct, iSerialNumber
+// in the device desciptor are changed to zeros.
+struct usb_string_descriptor_struct {
+	uint8_t bLength;
+	uint8_t bDescriptorType;
+	int16_t wString[];
+};
+static struct usb_string_descriptor_struct PROGMEM string0 = {
+	4,
+	3,
+	{0x0409}
+};
+static struct usb_string_descriptor_struct PROGMEM string1 = {
+	sizeof(STR_MANUFACTURER),
+	3,
+	STR_MANUFACTURER
+};
+static struct usb_string_descriptor_struct PROGMEM string2 = {
+	sizeof(STR_PRODUCT),
+	3,
+	STR_PRODUCT
+};
+
+// This table defines which descriptor data is sent for each specific
+// request from the host (in wValue and wIndex).
+static struct descriptor_list_struct {
+	uint16_t	wValue;
+	uint16_t	wIndex;
+	const uint8_t	*addr;
+	uint8_t		length;
+} PROGMEM descriptor_list[] = {
+	{0x0100, 0x0000, device_descriptor, sizeof(device_descriptor)},
+	{0x0200, 0x0000, config1_descriptor, sizeof(config1_descriptor)},
+	{0x2200, KEYBOARD_INTERFACE, keyboard_hid_report_desc, sizeof(keyboard_hid_report_desc)},
+	{0x2100, KEYBOARD_INTERFACE, config1_descriptor+KEYBOARD_HID_DESC_OFFSET, 9},
+	{0x2200, DEBUG_INTERFACE, debug_hid_report_desc, sizeof(debug_hid_report_desc)},
+	{0x2100, DEBUG_INTERFACE, config1_descriptor+DEBUG_HID_DESC_OFFSET, 9},
+	{0x0300, 0x0000, (const uint8_t *)&string0, 4},
+	{0x0301, 0x0409, (const uint8_t *)&string1, sizeof(STR_MANUFACTURER)},
+	{0x0302, 0x0409, (const uint8_t *)&string2, sizeof(STR_PRODUCT)}
+};
+#define NUM_DESC_LIST (sizeof(descriptor_list)/sizeof(struct descriptor_list_struct))
+
+
+/**************************************************************************
+ *
+ *  Variables - these are the only non-stack RAM usage
+ *
+ **************************************************************************/
+
+// zero when we are not configured, non-zero when enumerated
+static volatile uint8_t usb_configuration=0;
+
+// the time remaining before we transmit any partially full
+// packet, or send a zero length packet.
+static volatile uint8_t debug_flush_timer=0;
+
+// which modifier keys are currently pressed
+// 1=left ctrl,    2=left shift,   4=left alt,    8=left gui
+// 16=right ctrl, 32=right shift, 64=right alt, 128=right gui
+uint8_t keyboard_modifier_keys=0;
+
+// which keys are currently pressed, up to 6 keys may be down at once
+uint8_t keyboard_keys[6]={0,0,0,0,0,0};
+
+// protocol setting from the host.  We use exactly the same report
+// either way, so this variable only stores the setting since we
+// are required to be able to report which setting is in use.
+static uint8_t keyboard_protocol=1;
+
+// the idle configuration, how often we send the report to the
+// host (ms * 4) even when it hasn't changed
+static uint8_t keyboard_idle_config=125;
+
+// count until idle timeout
+static uint8_t keyboard_idle_count=0;
+
+// 1=num lock, 2=caps lock, 4=scroll lock, 8=compose, 16=kana
+volatile uint8_t keyboard_leds=0;
+
+
+/**************************************************************************
+ *
+ *  Public Functions - these are the API intended for the user
+ *
+ **************************************************************************/
+
+
+// initialize USB
+void usb_init(void)
+{
+	HW_CONFIG();
+	USB_FREEZE();				// enable USB
+	PLL_CONFIG();				// config PLL
+        while (!(PLLCSR & (1<<PLOCK))) ;	// wait for PLL lock
+        USB_CONFIG();				// start USB clock
+        UDCON = 0;				// enable attach resistor
+	usb_configuration = 0;
+        UDIEN = (1<<EORSTE)|(1<<SOFE);
+	sei();
+}
+
+// return 0 if the USB is not configured, or the configuration
+// number selected by the HOST
+uint8_t usb_configured(void)
+{
+	return usb_configuration;
+}
+
+
+// perform a single keystroke
+int8_t usb_keyboard_press(uint8_t key, uint8_t modifier)
+{
+	int8_t r;
+
+	keyboard_modifier_keys = modifier;
+	keyboard_keys[0] = key;
+	r = usb_keyboard_send();
+	if (r) return r;
+	keyboard_modifier_keys = 0;
+	keyboard_keys[0] = 0;
+	return usb_keyboard_send();
+}
+
+// send the contents of keyboard_keys and keyboard_modifier_keys
+int8_t usb_keyboard_send(void)
+{
+	uint8_t i, intr_state, timeout;
+
+	if (!usb_configuration) return -1;
+	intr_state = SREG;
+	cli();
+	UENUM = KEYBOARD_ENDPOINT;
+	timeout = UDFNUML + 50;
+	while (1) {
+		// are we ready to transmit?
+		if (UEINTX & (1<<RWAL)) break;
+		SREG = intr_state;
+		// has the USB gone offline?
+		if (!usb_configuration) return -1;
+		// have we waited too long?
+		if (UDFNUML == timeout) return -1;
+		// get ready to try checking again
+		intr_state = SREG;
+		cli();
+		UENUM = KEYBOARD_ENDPOINT;
+	}
+	UEDATX = keyboard_modifier_keys;
+	UEDATX = 0;
+	for (i=0; i<6; i++) {
+		UEDATX = keyboard_keys[i];
+	}
+	UEINTX = 0x3A;
+	keyboard_idle_count = 0;
+	SREG = intr_state;
+	return 0;
+}
+
+// transmit a character.  0 returned on success, -1 on error
+int8_t usb_debug_putchar(uint8_t c)
+{
+	static uint8_t previous_timeout=0;
+	uint8_t timeout, intr_state;
+
+	// if we're not online (enumerated and configured), error
+	if (!usb_configuration) return -1;
+	// interrupts are disabled so these functions can be
+	// used from the main program or interrupt context,
+	// even both in the same program!
+	intr_state = SREG;
+	cli();
+	UENUM = DEBUG_TX_ENDPOINT;
+	// if we gave up due to timeout before, don't wait again
+	if (previous_timeout) {
+		if (!(UEINTX & (1<<RWAL))) {
+			SREG = intr_state;
+			return -1;
+		}
+		previous_timeout = 0;
+	}
+	// wait for the FIFO to be ready to accept data
+	timeout = UDFNUML + 4;
+	while (1) {
+		// are we ready to transmit?
+		if (UEINTX & (1<<RWAL)) break;
+		SREG = intr_state;
+		// have we waited too long?
+		if (UDFNUML == timeout) {
+			previous_timeout = 1;
+			return -1;
+		}
+		// has the USB gone offline?
+		if (!usb_configuration) return -1;
+		// get ready to try checking again
+		intr_state = SREG;
+		cli();
+		UENUM = DEBUG_TX_ENDPOINT;
+	}
+	// actually write the byte into the FIFO
+	UEDATX = c;
+	// if this completed a packet, transmit it now!
+	if (!(UEINTX & (1<<RWAL))) {
+		UEINTX = 0x3A;
+		debug_flush_timer = 0;
+	} else {
+		debug_flush_timer = 2;
+	}
+	SREG = intr_state;
+	return 0;
+}
+
+
+// immediately transmit any buffered output.
+void usb_debug_flush_output(void)
+{
+	uint8_t intr_state;
+
+	intr_state = SREG;
+	cli();
+	if (debug_flush_timer) {
+		UENUM = DEBUG_TX_ENDPOINT;
+		while ((UEINTX & (1<<RWAL))) {
+			UEDATX = 0;
+		}
+		UEINTX = 0x3A;
+		debug_flush_timer = 0;
+	}
+	SREG = intr_state;
+}
+
+
+
+/**************************************************************************
+ *
+ *  Private Functions - not intended for general user consumption....
+ *
+ **************************************************************************/
+
+
+
+// USB Device Interrupt - handle all device-level events
+// the transmit buffer flushing is triggered by the start of frame
+//
+ISR(USB_GEN_vect)
+{
+	uint8_t intbits, t, i;
+	static uint8_t div4=0;
+
+        intbits = UDINT;
+        UDINT = 0;
+        if (intbits & (1<<EORSTI)) {
+		UENUM = 0;
+		UECONX = 1;
+		UECFG0X = EP_TYPE_CONTROL;
+		UECFG1X = EP_SIZE(ENDPOINT0_SIZE) | EP_SINGLE_BUFFER;
+		UEIENX = (1<<RXSTPE);
+		usb_configuration = 0;
+        }
+	if ((intbits & (1<<SOFI)) && usb_configuration) {
+		t = debug_flush_timer;
+		if (t) {
+			debug_flush_timer = -- t;
+			if (!t) {
+				UENUM = DEBUG_TX_ENDPOINT;
+				while ((UEINTX & (1<<RWAL))) {
+					UEDATX = 0;
+				}
+				UEINTX = 0x3A;
+			}
+		}
+		if (keyboard_idle_config && (++div4 & 3) == 0) {
+			UENUM = KEYBOARD_ENDPOINT;
+			if (UEINTX & (1<<RWAL)) {
+				keyboard_idle_count++;
+				if (keyboard_idle_count == keyboard_idle_config) {
+					keyboard_idle_count = 0;
+					UEDATX = keyboard_modifier_keys;
+					UEDATX = 0;
+					for (i=0; i<6; i++) {
+						UEDATX = keyboard_keys[i];
+					}
+					UEINTX = 0x3A;
+				}
+			}
+		}
+	}
+}
+
+
+
+// Misc functions to wait for ready and send/receive packets
+static inline void usb_wait_in_ready(void)
+{
+	while (!(UEINTX & (1<<TXINI))) ;
+}
+static inline void usb_send_in(void)
+{
+	UEINTX = ~(1<<TXINI);
+}
+static inline void usb_wait_receive_out(void)
+{
+	while (!(UEINTX & (1<<RXOUTI))) ;
+}
+static inline void usb_ack_out(void)
+{
+	UEINTX = ~(1<<RXOUTI);
+}
+
+
+
+// USB Endpoint Interrupt - endpoint 0 is handled here.  The
+// other endpoints are manipulated by the user-callable
+// functions, and the start-of-frame interrupt.
+//
+ISR(USB_COM_vect)
+{
+        uint8_t intbits;
+	const uint8_t *list;
+        const uint8_t *cfg;
+	uint8_t i, n, len, en;
+	uint8_t bmRequestType;
+	uint8_t bRequest;
+	uint16_t wValue;
+	uint16_t wIndex;
+	uint16_t wLength;
+	uint16_t desc_val;
+	const uint8_t *desc_addr;
+	uint8_t	desc_length;
+
+        UENUM = 0;
+	intbits = UEINTX;
+        if (intbits & (1<<RXSTPI)) {
+                bmRequestType = UEDATX;
+                bRequest = UEDATX;
+                wValue = UEDATX;
+                wValue |= (UEDATX << 8);
+                wIndex = UEDATX;
+                wIndex |= (UEDATX << 8);
+                wLength = UEDATX;
+                wLength |= (UEDATX << 8);
+                UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
+                if (bRequest == GET_DESCRIPTOR) {
+			list = (const uint8_t *)descriptor_list;
+			for (i=0; ; i++) {
+				if (i >= NUM_DESC_LIST) {
+					UECONX = (1<<STALLRQ)|(1<<EPEN);  //stall
+					return;
+				}
+				desc_val = pgm_read_word(list);
+				if (desc_val != wValue) {
+					list += sizeof(struct descriptor_list_struct);
+					continue;
+				}
+				list += 2;
+				desc_val = pgm_read_word(list);
+				if (desc_val != wIndex) {
+					list += sizeof(struct descriptor_list_struct)-2;
+					continue;
+				}
+				list += 2;
+				desc_addr = (const uint8_t *)pgm_read_word(list);
+				list += 2;
+				desc_length = pgm_read_byte(list);
+				break;
+			}
+			len = (wLength < 256) ? wLength : 255;
+			if (len > desc_length) len = desc_length;
+			do {
+				// wait for host ready for IN packet
+				do {
+					i = UEINTX;
+				} while (!(i & ((1<<TXINI)|(1<<RXOUTI))));
+				if (i & (1<<RXOUTI)) return;	// abort
+				// send IN packet
+				n = len < ENDPOINT0_SIZE ? len : ENDPOINT0_SIZE;
+				for (i = n; i; i--) {
+					UEDATX = pgm_read_byte(desc_addr++);
+				}
+				len -= n;
+				usb_send_in();
+			} while (len || n == ENDPOINT0_SIZE);
+			return;
+                }
+		if (bRequest == SET_ADDRESS) {
+			usb_send_in();
+			usb_wait_in_ready();
+			UDADDR = wValue | (1<<ADDEN);
+			return;
+		}
+		if (bRequest == SET_CONFIGURATION && bmRequestType == 0) {
+			usb_configuration = wValue;
+			usb_send_in();
+			cfg = endpoint_config_table;
+			for (i=1; i<5; i++) {
+				UENUM = i;
+				en = pgm_read_byte(cfg++);
+				UECONX = en;
+				if (en) {
+					UECFG0X = pgm_read_byte(cfg++);
+					UECFG1X = pgm_read_byte(cfg++);
+				}
+			}
+        		UERST = 0x1E;
+        		UERST = 0;
+			return;
+		}
+		if (bRequest == GET_CONFIGURATION && bmRequestType == 0x80) {
+			usb_wait_in_ready();
+			UEDATX = usb_configuration;
+			usb_send_in();
+			return;
+		}
+
+		if (bRequest == GET_STATUS) {
+			usb_wait_in_ready();
+			i = 0;
+			#ifdef SUPPORT_ENDPOINT_HALT
+			if (bmRequestType == 0x82) {
+				UENUM = wIndex;
+				if (UECONX & (1<<STALLRQ)) i = 1;
+				UENUM = 0;
+			}
+			#endif
+			UEDATX = i;
+			UEDATX = 0;
+			usb_send_in();
+			return;
+		}
+		#ifdef SUPPORT_ENDPOINT_HALT
+		if ((bRequest == CLEAR_FEATURE || bRequest == SET_FEATURE)
+		  && bmRequestType == 0x02 && wValue == 0) {
+			i = wIndex & 0x7F;
+			if (i >= 1 && i <= MAX_ENDPOINT) {
+				usb_send_in();
+				UENUM = i;
+				if (bRequest == SET_FEATURE) {
+					UECONX = (1<<STALLRQ)|(1<<EPEN);
+				} else {
+					UECONX = (1<<STALLRQC)|(1<<RSTDT)|(1<<EPEN);
+					UERST = (1 << i);
+					UERST = 0;
+				}
+				return;
+			}
+		}
+		#endif
+		if (wIndex == KEYBOARD_INTERFACE) {
+			if (bmRequestType == 0xA1) {
+				if (bRequest == HID_GET_REPORT) {
+					usb_wait_in_ready();
+					UEDATX = keyboard_modifier_keys;
+					UEDATX = 0;
+					for (i=0; i<6; i++) {
+						UEDATX = keyboard_keys[i];
+					}
+					usb_send_in();
+					return;
+				}
+				if (bRequest == HID_GET_IDLE) {
+					usb_wait_in_ready();
+					UEDATX = keyboard_idle_config;
+					usb_send_in();
+					return;
+				}
+				if (bRequest == HID_GET_PROTOCOL) {
+					usb_wait_in_ready();
+					UEDATX = keyboard_protocol;
+					usb_send_in();
+					return;
+				}
+			}
+			if (bmRequestType == 0x21) {
+				if (bRequest == HID_SET_REPORT) {
+					usb_wait_receive_out();
+					keyboard_leds = UEDATX;
+					usb_ack_out();
+					usb_send_in();
+					return;
+				}
+				if (bRequest == HID_SET_IDLE) {
+					keyboard_idle_config = (wValue >> 8);
+					keyboard_idle_count = 0;
+					//usb_wait_in_ready();
+					usb_send_in();
+					return;
+				}
+				if (bRequest == HID_SET_PROTOCOL) {
+					keyboard_protocol = wValue;
+					//usb_wait_in_ready();
+					usb_send_in();
+					return;
+				}
+			}
+		}
+		if (wIndex == DEBUG_INTERFACE) {
+			if (bRequest == HID_GET_REPORT && bmRequestType == 0xA1) {
+				len = wLength;
+				do {
+					// wait for host ready for IN packet
+					do {
+						i = UEINTX;
+					} while (!(i & ((1<<TXINI)|(1<<RXOUTI))));
+					if (i & (1<<RXOUTI)) return;	// abort
+					// send IN packet
+					n = len < ENDPOINT0_SIZE ? len : ENDPOINT0_SIZE;
+					for (i = n; i; i--) {
+						UEDATX = 0;
+					}
+					len -= n;
+					usb_send_in();
+				} while (len || n == ENDPOINT0_SIZE);
+				return;
+			}
+		}
+	}
+	UECONX = (1<<STALLRQ) | (1<<EPEN);	// stall
+}
+
+
diff --git a/usb_keyboard_debug.h b/usb_keyboard_debug.h
new file mode 100644
index 0000000000..a76cc35142
--- /dev/null
+++ b/usb_keyboard_debug.h
@@ -0,0 +1,203 @@
+#ifndef usb_serial_h__
+#define usb_serial_h__
+
+#include <stdint.h>
+
+void usb_init(void);			// initialize everything
+uint8_t usb_configured(void);		// is the USB port configured
+
+int8_t usb_keyboard_press(uint8_t key, uint8_t modifier);
+int8_t usb_keyboard_send(void);
+extern uint8_t keyboard_modifier_keys;
+extern uint8_t keyboard_keys[6];
+extern volatile uint8_t keyboard_leds;
+
+int8_t usb_debug_putchar(uint8_t c);	// transmit a character
+void usb_debug_flush_output(void);	// immediately transmit any buffered output
+#define USB_DEBUG_HID
+
+#define KEY_CTRL	0x01
+#define KEY_SHIFT	0x02
+#define KEY_ALT		0x04
+#define KEY_GUI		0x08
+#define KEY_LEFT_CTRL	0x01
+#define KEY_LEFT_SHIFT	0x02
+#define KEY_LEFT_ALT	0x04
+#define KEY_LEFT_GUI	0x08
+#define KEY_RIGHT_CTRL	0x10
+#define KEY_RIGHT_SHIFT	0x20
+#define KEY_RIGHT_ALT	0x40
+#define KEY_RIGHT_GUI	0x80
+
+#define KEY_A		4
+#define KEY_B		5
+#define KEY_C		6
+#define KEY_D		7
+#define KEY_E		8
+#define KEY_F		9
+#define KEY_G		10
+#define KEY_H		11
+#define KEY_I		12
+#define KEY_J		13
+#define KEY_K		14
+#define KEY_L		15
+#define KEY_M		16
+#define KEY_N		17
+#define KEY_O		18
+#define KEY_P		19
+#define KEY_Q		20
+#define KEY_R		21
+#define KEY_S		22
+#define KEY_T		23
+#define KEY_U		24
+#define KEY_V		25
+#define KEY_W		26
+#define KEY_X		27
+#define KEY_Y		28
+#define KEY_Z		29
+#define KEY_1		30
+#define KEY_2		31
+#define KEY_3		32
+#define KEY_4		33
+#define KEY_5		34
+#define KEY_6		35
+#define KEY_7		36
+#define KEY_8		37
+#define KEY_9		38
+#define KEY_0		39
+#define KEY_ENTER	40	
+#define KEY_ESC		41
+#define KEY_BACKSPACE	42	
+#define KEY_TAB		43
+#define KEY_SPACE	44	
+#define KEY_MINUS	45
+#define KEY_EQUAL	46
+#define KEY_LEFT_BRACE	47
+#define KEY_RIGHT_BRACE	48
+#define KEY_BACKSLASH	49
+#define KEY_NUMBER	50
+#define KEY_SEMICOLON	51
+#define KEY_QUOTE	52
+#define KEY_TILDE	53
+#define KEY_COMMA	54
+#define KEY_PERIOD	55
+#define KEY_SLASH	56
+#define KEY_CAPS_LOCK	57
+#define KEY_F1		58
+#define KEY_F2		59
+#define KEY_F3		60
+#define KEY_F4		61
+#define KEY_F5		62
+#define KEY_F6		63
+#define KEY_F7		64
+#define KEY_F8		65
+#define KEY_F9		66
+#define KEY_F10		67
+#define KEY_F11		68
+#define KEY_F12		69
+#define KEY_PRINTSCREEN	70		
+#define KEY_SCROLL_LOCK	71		
+#define KEY_PAUSE	72
+#define KEY_INSERT	73	
+#define KEY_HOME	74
+#define KEY_PAGE_UP	75
+#define KEY_DELETE	76
+#define KEY_END		77
+#define KEY_PAGE_DOWN	78	
+#define KEY_RIGHT	79
+#define KEY_LEFT	80
+#define KEY_DOWN	81
+#define KEY_UP		82
+#define KEY_NUM_LOCK	83
+#define KEYPAD_SLASH	84	
+#define KEYPAD_ASTERIX	85	
+#define KEYPAD_MINUS	86	
+#define KEYPAD_PLUS	87	
+#define KEYPAD_ENTER	88	
+#define KEYPAD_1	89
+#define KEYPAD_2	90
+#define KEYPAD_3	91	
+#define KEYPAD_4	92	
+#define KEYPAD_5	93	
+#define KEYPAD_6	94	
+#define KEYPAD_7	95	
+#define KEYPAD_8	96	
+#define KEYPAD_9	97	
+#define KEYPAD_0	98		
+#define KEYPAD_PERIOD	99		
+
+
+
+
+// Everything below this point is only intended for usb_serial.c
+#ifdef USB_SERIAL_PRIVATE_INCLUDE
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+
+#define EP_TYPE_CONTROL			0x00
+#define EP_TYPE_BULK_IN			0x81
+#define EP_TYPE_BULK_OUT		0x80
+#define EP_TYPE_INTERRUPT_IN		0xC1
+#define EP_TYPE_INTERRUPT_OUT		0xC0
+#define EP_TYPE_ISOCHRONOUS_IN		0x41
+#define EP_TYPE_ISOCHRONOUS_OUT		0x40
+
+#define EP_SINGLE_BUFFER		0x02
+#define EP_DOUBLE_BUFFER		0x06
+
+#define EP_SIZE(s)	((s) == 64 ? 0x30 :	\
+			((s) == 32 ? 0x20 :	\
+			((s) == 16 ? 0x10 :	\
+			             0x00)))
+
+#define MAX_ENDPOINT		4
+
+#define LSB(n) (n & 255)
+#define MSB(n) ((n >> 8) & 255)
+
+#if defined(__AVR_AT90USB162__)
+#define HW_CONFIG() 
+#define PLL_CONFIG() (PLLCSR = ((1<<PLLE)|(1<<PLLP0)))
+#define USB_CONFIG() (USBCON = (1<<USBE))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_ATmega32U4__)
+#define HW_CONFIG() (UHWCON = 0x01)
+#define PLL_CONFIG() (PLLCSR = 0x12)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_AT90USB646__)
+#define HW_CONFIG() (UHWCON = 0x81)
+#define PLL_CONFIG() (PLLCSR = 0x1A)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_AT90USB1286__)
+#define HW_CONFIG() (UHWCON = 0x81)
+#define PLL_CONFIG() (PLLCSR = 0x16)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#endif
+
+// standard control endpoint request types
+#define GET_STATUS			0
+#define CLEAR_FEATURE			1
+#define SET_FEATURE			3
+#define SET_ADDRESS			5
+#define GET_DESCRIPTOR			6
+#define GET_CONFIGURATION		8
+#define SET_CONFIGURATION		9
+#define GET_INTERFACE			10
+#define SET_INTERFACE			11
+// HID (human interface device)
+#define HID_GET_REPORT			1
+#define HID_GET_IDLE			2
+#define HID_GET_PROTOCOL		3
+#define HID_SET_REPORT			9
+#define HID_SET_IDLE			10
+#define HID_SET_PROTOCOL		11
+// CDC (communication class device)
+#define CDC_SET_LINE_CODING		0x20
+#define CDC_GET_LINE_CODING		0x21
+#define CDC_SET_CONTROL_LINE_STATE	0x22
+#endif
+#endif