Added source code

LICENSE

@@ -1,5 +1,5 @@
 MIT License
-Copyright (c) <year> <copyright holders>
+Copyright (c) 2017 Clayton G. Hobbs
 
 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:
 

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.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

example.c

@@ -0,0 +1,130 @@
+/* Keyboard example 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.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))
+
+#undef STR_MANUFACTURER
+#undef STR_PRODUCT
+
+#define STR_MANUFACTURER	L"Clayton G. Hobbs"
+#define STR_PRODUCT		L"Music Score Foot Pedal"
+
+uint16_t idle_count = 0;
+uint8_t pressed = 0;
+uint8_t last = 0;
+
+int main(void)
+{
+	uint8_t d, mask;
+	uint8_t d_prev=0xFF;
+
+	// set for 16 MHz clock
+	CPU_PRESCALE(0);
+
+	// Configure all port B pins as inputs with pullup resistors.
+	// See the "Using I/O Pins" page for details.
+	// http://www.pjrc.com/teensy/pins.html
+	DDRD = 0x00;
+	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 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);
+
+	while (1) {
+		// read all port B and port D pins
+		d = PIND;
+		// check if any pins are low, but were high previously
+		mask = 1 << 5;
+		if (((d & mask) == 0) && (d_prev & mask) != 0) {
+            cli();
+            pressed += 1;
+            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".
+		d_prev = d;
+		_delay_ms(2);
+	}
+}
+
+// This interrupt routine is run approx 61 times per second.
+// All keypresses are sent here.  When a single press occurred with nothing
+// else for a whole second, send a page down.  Further presses less than a
+// second apart following that timeout send more page downs.  If after a period
+// of inactivity, two presses occur within one second, send a page up.  Further
+// presses less than a second apart send more page ups.
+ISR(TIMER0_OVF_vect)
+{
+	idle_count++;
+	if (idle_count > 30 && pressed > 0 && last != KEY_PAGE_UP) {
+        usb_keyboard_press(KEY_PAGE_DOWN, 0);
+        pressed -= 1;
+		idle_count = 0;
+        last = KEY_PAGE_DOWN;
+	} else if (idle_count <= 30 && pressed == 2 && last != KEY_PAGE_DOWN) {
+        usb_keyboard_press(KEY_PAGE_UP, 0);
+        pressed -= 1;
+        idle_count = 0;
+        last = KEY_PAGE_UP;
+    } else if (idle_count <= 30 && pressed > 0 && last == KEY_PAGE_DOWN) {
+        usb_keyboard_press(KEY_PAGE_DOWN, 0);
+        pressed -= 1;
+		idle_count = 0;
+        last = KEY_PAGE_DOWN;
+    } else if (idle_count > 30 && pressed == 0) {
+        last = 0;
+        pressed = 0;
+        idle_count = 0;
+    } else if (idle_count > 30 && pressed > 0 && last == KEY_PAGE_UP) {
+        last = 0;
+        pressed = 0;
+        idle_count = 0;
+    }
+}

usb_keyboard.c

@@ -0,0 +1,592 @@
+/* USB Keyboard 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.h"
+
+/**************************************************************************
+ *
+ *  Configurable Options
+ *
+ **************************************************************************/
+
+// You can change these to give your code its own name.
+#define STR_MANUFACTURER	L"Clayton G. Hobbs"
+#define STR_PRODUCT		L"Music Score Foot Pedal"
+
+
+// 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		0x047C
+
+
+// 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
+
+static const uint8_t PROGMEM endpoint_config_table[] = {
+	0,
+	0,
+	1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(KEYBOARD_SIZE) | KEYBOARD_BUFFER,
+	0
+};
+
+
+/**************************************************************************
+ *
+ *  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 const 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 const 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
+};
+
+#define CONFIG1_DESC_SIZE        (9+9+9+7)
+#define KEYBOARD_HID_DESC_OFFSET (9+9)
+static const 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),
+	1,					// 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
+};
+
+// 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 const struct usb_string_descriptor_struct PROGMEM string0 = {
+	4,
+	3,
+	{0x0409}
+};
+static const struct usb_string_descriptor_struct PROGMEM string1 = {
+	sizeof(STR_MANUFACTURER),
+	3,
+	STR_MANUFACTURER
+};
+static const 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;
+} const 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},
+	{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;
+
+// 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;
+}
+
+/**************************************************************************
+ *
+ *  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) {
+		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_send_in();
+					return;
+				}
+				if (bRequest == HID_SET_PROTOCOL) {
+					keyboard_protocol = wValue;
+					usb_send_in();
+					return;
+				}
+			}
+		}
+	}
+	UECONX = (1<<STALLRQ) | (1<<EPEN);	// stall
+}
+
+

usb_keyboard.h

@@ -0,0 +1,206 @@
+#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;
+
+// This file does not include the HID debug functions, so these empty
+// macros replace them with nothing, so users can compile code that
+// has calls to these functions.
+#define usb_debug_putchar(c)
+#define usb_debug_flush_output()
+
+
+#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