diff --git a/avr/main.c b/avr/main.c
index efc9e6f..9b4a61b 100644
--- a/avr/main.c
+++ b/avr/main.c
@@ -1,10 +1,11 @@
 #include <stdio.h>
 
+#include <avr/io.h>
 #include <avr/interrupt.h>
 #include <avr/sleep.h>
 
 #include <tabby/clock.h>
-#include <tabby/packet.h>
+#include <tabby/command.h>
 
 #include <tabby/avr/uart.h>
 #include <tabby/avr/buffer.h>
@@ -28,7 +29,7 @@ static tabby_clock_speed  speed  = TABBY_CLOCK_SPEED_8192HZ;
 /*
  * Internal clock source interrupt vector
  */
-ISR(TIM0_COMPB_vect) {
+ISR(TIMER0_COMPB_vect) {
     value_in >>= 1;
 
     if (PORTB & (1 << PORTB2)) {
@@ -68,7 +69,7 @@ ISR(TIM0_COMPB_vect) {
  * SPI byte receipt interrupt vector
  */
 ISR(SPI_STC_vect) {
-    uart_putchar(SPDR);
+    uart_putchar(SPDR, NULL);
 
     if (buffer.cur < buffer.len) {
         SPDR = buffer.data[buffer.cur++];
@@ -83,22 +84,22 @@ static void setup_clock_internal(tabby_clock_speed speed) {
     /*
      * Configure MISO as output
      */
-    DDB3 |= (1 << PORTB3);
+    DDRB |= (1 << DDB3);
 
     /*
      * Configure MOSI as input
      */
-    DDB2 &= ~(1 << PORTB2);
+    DDRB &= ~(1 << DDB2);
 
     /*
      * Configure SCK pin as output
      */
-    DDB1 |= (1 << PORTB1);
+    DDRB |= (1 << DDB1);
 
     /*
      * Enable timer interrupt vector
      */
-    TIMSK = (1 << TOIE1);
+    TIMSK0 = (1 << TOIE1);
 
     /*
      * Reset timer counter to zero
@@ -122,17 +123,17 @@ static void setup_clock_external() {
      */
     TCCR1B = 0;
     OCR1A  = 0;
-    TIMSK  = 0;
+    TIMSK0 = 0;
 
     /*
      * Configure MISO as output
      */
-    DDB3 |= (1 << PORTB3);
+    DDRB |= (1 << DDB3);
 
     /*
      * Configure MOSI as input
      */
-    DDB2 &= ~(1 << PORTB2);
+    DDRB &= ~(1 << DDB3);
 
     /*
      * Set SPI slave mode, and shift in/out most significant bit first
@@ -149,22 +150,20 @@ static void setup_clock_external() {
      */
     SPDR = 0;
 
-    buf.len = 0;
-    buf.cur = 0;
+    buffer.len = 0;
+    buffer.cur = 0;
 }
 
-static void snooze() {
+/*static void snooze() {
     set_sleep_mode(mode);
     sleep_enable();
     sleep_mode();
     sleep_disable();
-}
+}*/
 
 int main() {
     tabby_command state = TABBY_COMMAND_NONE;
 
-    uint8_t last = 0x00;
-
     int received = 0;
 
     /*
@@ -250,13 +249,10 @@ int main() {
                 goto reset;
         }
 
-        last = c;
-
         continue;
 
 reset:
         state    = TABBY_COMMAND_NONE;
-        last     = 0;
         received = 0;
 
         buffer.len  = 0;
diff --git a/configure b/configure
new file mode 100755
index 0000000..385055b
--- /dev/null
+++ b/configure
@@ -0,0 +1,100 @@
+#! /bin/sh
+
+OS=`uname -s`
+DEBUG=0
+
+create_linux_config_h() {
+    cat <<EOF > src/config.h
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include <endian.h>
+#endif /* _CONFIG_H */
+EOF
+}
+
+create_darwin_config_h() {
+    cat <<EOF > src/config.h
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include <architecture/byte_order.h>
+
+#ifdef __LITTLE_ENDIAN__
+#define __DO_SWAP_BYTES
+#endif /* _DO_SWAP_BYTES */
+#endif /* _CONFIG_H */
+EOF
+}
+
+create_common_build_mk() {
+    if [ "$DEBUG" = 1 ]; then
+        cat <<'EOF' > mk/build.mk
+CGFLAGS		= -g -fno-inline
+EOF
+	else
+		cat <<'EOF' > mk/build.mk
+CGFLAGS		=
+EOF
+    fi
+
+	cat <<'EOF' >> mk/build.mk
+CWFLAGS		= -Wall
+COFLAGS		= -O2
+CFLAGS		= $(CGFLAGS) $(CWFLAGS) $(COFLAGS)
+EOF
+}
+
+create_linux_build_mk() {
+    create_common_build_mk $@
+
+    cat <<'EOF' >> mk/build.mk
+LLFLAGS		= -shared -Wl,-soname=$(SONAME)
+
+STATIC		= lib$(LIBNAME).a
+
+SONAME_SHORT	= lib$(LIBNAME).so
+SONAME		= $(SONAME_SHORT).$(VERSION_MAJOR)
+SONAME_FULL	= $(SONAME_SHORT).$(VERSION)
+
+PREFIX      = /usr/local
+EOF
+}
+
+create_darwin_build_mk() {
+    create_common_build_mk $@
+
+    cat <<'EOF' >> mk/build.mk
+LLFLAGS		= -dynamiclib -current_version $(VERSION)
+
+STATIC		= lib$(LIBNAME).a
+
+SONAME_SHORT	= lib$(LIBNAME).dylib
+SONAME		= lib$(LIBNAME).$(VERSION_MAJOR).dylib
+SONAME_FULL	= lib$(LIBNAME).$(VERSION).dylib
+
+PREFIX		= /usr/local
+EOF
+}
+
+for arg in $@; do
+    case $arg in
+        "--enable-debug")
+            DEBUG=1
+        ;;
+    esac
+done
+
+if [ ! -d "mk" ]; then
+    mkdir -m 0755 mk
+fi
+
+case $OS in
+    Linux)
+        create_linux_config_h
+		create_linux_build_mk
+    ;;
+
+    Darwin)
+        create_darwin_config_h
+		create_darwin_build_mk
+    ;;
+esac
diff --git a/include/tabby/clock.h b/include/tabby/clock.h
index 21d6e41..5e0655c 100644
--- a/include/tabby/clock.h
+++ b/include/tabby/clock.h
@@ -4,7 +4,7 @@
 typedef enum {
     TABBY_CLOCK_SOURCE_INTERNAL = 0x01,
     TABBY_CLOCK_SOURCE_EXTERNAL = 0x02
-} tabby_clock_mode;
+} tabby_clock_source;
 
 typedef enum {
     TABBY_CLOCK_SPEED_8192HZ   = 0x01,