diff --git a/config.h b/config.h
index 9c768cf..4dec02b 100644
--- a/config.h
+++ b/config.h
@@ -2,8 +2,8 @@
   config.h - compile time configuration
   Part of Grbl
 
+  Copyright (c) 2011-2013 Sungeun K. Jeon
   Copyright (c) 2009-2011 Simen Svale Skogsrud
-  Copyright (c) 2011-2012 Sungeun K. Jeon
 
   Grbl is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -19,29 +19,24 @@
   along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef config_h
-#define config_h
+// This file contains compile-time configurations for Grbl's internal system. For the most part,
+// users will not need to directly modify these, but they are here for specific needs, i.e.
+// performance tuning or adjusting to non-typical machines.
 
 // IMPORTANT: Any changes here requires a full re-compiling of the source code to propagate them.
 
+#ifndef config_h
+#define config_h
+
 // Default settings. Used when resetting EEPROM. Change to desired name in defaults.h
 #define DEFAULTS_GENERIC
 
 // Serial baud rate
 #define BAUD_RATE 9600
 
-// Pin mappings, pick one and comment others
-#define DEFAULT_328P
-//#define DEFAULT_2560
-//#define CUSTOM_PINS
-
-if defined(DEFAULT_328P)
-  #include config_default_328p.h
-elif defined(DEFAULT_2560)
-  #include config_default_2560.h
-elif defined(CUSTOM_PINS)
-  #include config_custom.h // Create from the closest pre-existing config_default_*.h
-#endif
+// Default pin mappings. Grbl officially supports the Arduino Uno only. Other processor types
+// may exist from user-supplied templates or directly user-defined in pin_map.h
+#define ARDUINO_UNO
 
 // Define runtime command special characters. These characters are 'picked-off' directly from the
 // serial read data stream and are not passed to the grbl line execution parser. Select characters
diff --git a/config_default_2560.h b/config_default_2560.h
deleted file mode 100644
index 5ddb52e..0000000
--- a/config_default_2560.h
+++ /dev/null
@@ -1,70 +0,0 @@
-#ifndef config_default_2560_h
-#define config_default_2560_h
-
-// Define pin-assignments
-// NOTE: All step bit and direction pins must be on the same port.
-#define STEPPING_DDR      DDRA
-#define STEPPING_PORT     PORTA
-#define STEPPING_PIN      PINA
-#define X_STEP_BIT        0 // MEGA2560 Digital Pin 22
-#define Y_STEP_BIT        2 // MEGA2560 Digital Pin 24
-#define Z_STEP_BIT        4 // MEGA2560 Digital Pin 26
-#define C_STEP_BIT        6 // MEGA2560 Digital Pin 28
-#define X_DIRECTION_BIT   1 // MEGA2560 Digital Pin 23
-#define Y_DIRECTION_BIT   3 // MEGA2560 Digital Pin 25
-#define Z_DIRECTION_BIT   5 // MEGA2560 Digital Pin 27
-#define C_DIRECTION_BIT   7 // MEGA2560 Digital Pin 29
-#define STEP_MASK ((1<<X_STEP_BIT)|(1<<Y_STEP_BIT)|(1<<Z_STEP_BIT)) // All step bits
-#define DIRECTION_MASK ((1<<X_DIRECTION_BIT)|(1<<Y_DIRECTION_BIT)|(1<<Z_DIRECTION_BIT)) // All direction bits
-#define STEPPING_MASK (STEP_MASK | DIRECTION_MASK) // All stepping-related bits (step/direction)
-
-#define STEPPERS_DISABLE_DDR   DDRC
-#define STEPPERS_DISABLE_PORT  PORTC
-#define STEPPERS_DISABLE_BIT   7 // MEGA2560 Digital Pin 30
-#define STEPPERS_DISABLE_MASK (1<<STEPPERS_DISABLE_BIT)
-
-// NOTE: All limit bit pins must be on the same port
-#define LIMIT_DDR       DDRC
-#define LIMIT_PORT      PORTC
-#define LIMIT_PIN       PINC
-#define X_LIMIT_BIT     6 // MEGA2560 Digital Pin 31
-#define Y_LIMIT_BIT     5 // MEGA2560 Digital Pin 32
-#define Z_LIMIT_BIT     4 // MEGA2560 Digital Pin 33
-#define C_LIMIT_BIT     3 // MEGA2560 Digital Pin 34
-#define LIMIT_INT       PCIE0  // Pin change interrupt enable pin
-#define LIMIT_INT_vect  PCINT0_vect 
-#define LIMIT_PCMSK     PCMSK0 // Pin change interrupt register
-#define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
-
-#define SPINDLE_ENABLE_DDR   DDRC
-#define SPINDLE_ENABLE_PORT  PORTC
-#define SPINDLE_ENABLE_BIT   2 // MEGA2560 Digital Pin 35
-
-#define SPINDLE_DIRECTION_DDR   DDRC
-#define SPINDLE_DIRECTION_PORT  PORTC
-#define SPINDLE_DIRECTION_BIT   1 // MEGA2560 Digital Pin 36
-
-#define COOLANT_FLOOD_DDR   DDRC
-#define COOLANT_FLOOD_PORT  PORTC
-#define COOLANT_FLOOD_BIT   0 // MEGA2560 Digital Pin 37
-
-// NOTE: Uno analog pins 4 and 5 are reserved for an i2c interface, and may be installed at
-// a later date if flash and memory space allows.
-// #define ENABLE_M7  // Mist coolant disabled by default. Uncomment to enable.
-#ifdef ENABLE_M7
-  #define COOLANT_MIST_DDR   DDRC
-  #define COOLANT_MIST_PORT  PORTC
-  #define COOLANT_MIST_BIT   0 // MEGA2560 Digital Pin 37
-#endif  
-
-// NOTE: All pinouts pins must be on the same port
-#define PINOUT_DDR       DDRC
-#define PINOUT_PIN       PINC
-#define PINOUT_PORT      PORTC
-#define PIN_RESET        0  // Uno Analog Pin 0
-#define PIN_FEED_HOLD    1  // Uno Analog Pin 1
-#define PIN_CYCLE_START  2  // Uno Analog Pin 2
-#define PINOUT_INT       PCIE1  // Pin change interrupt enable pin
-#define PINOUT_INT_vect  PCINT1_vect
-#define PINOUT_PCMSK     PCMSK1 // Pin change interrupt register
-#define PINOUT_MASK ((1<<PIN_RESET)|(1<<PIN_FEED_HOLD)|(1<<PIN_CYCLE_START))
diff --git a/config_default_328p.h b/config_default_328p.h
deleted file mode 100644
index 4497f23..0000000
--- a/config_default_328p.h
+++ /dev/null
@@ -1,66 +0,0 @@
-#ifndef config_default_2560_h
-#define config_default_2560_h
-
-// Define pin-assignments
-// NOTE: All step bit and direction pins must be on the same port.
-#define STEPPING_DDR       DDRD
-#define STEPPING_PORT      PORTD
-#define X_STEP_BIT         2  // Uno Digital Pin 2
-#define Y_STEP_BIT         3  // Uno Digital Pin 3
-#define Z_STEP_BIT         4  // Uno Digital Pin 4
-#define X_DIRECTION_BIT    5  // Uno Digital Pin 5
-#define Y_DIRECTION_BIT    6  // Uno Digital Pin 6
-#define Z_DIRECTION_BIT    7  // Uno Digital Pin 7
-#define STEP_MASK ((1<<X_STEP_BIT)|(1<<Y_STEP_BIT)|(1<<Z_STEP_BIT)) // All step bits
-#define DIRECTION_MASK ((1<<X_DIRECTION_BIT)|(1<<Y_DIRECTION_BIT)|(1<<Z_DIRECTION_BIT)) // All direction bits
-#define STEPPING_MASK (STEP_MASK | DIRECTION_MASK) // All stepping-related bits (step/direction)
-
-#define STEPPERS_DISABLE_DDR    DDRB
-#define STEPPERS_DISABLE_PORT   PORTB
-#define STEPPERS_DISABLE_BIT    0  // Uno Digital Pin 8
-#define STEPPERS_DISABLE_MASK (1<<STEPPERS_DISABLE_BIT)
-
-// NOTE: All limit bit pins must be on the same port
-#define LIMIT_DDR       DDRB
-#define LIMIT_PIN       PINB
-#define LIMIT_PORT      PORTB
-#define X_LIMIT_BIT     1  // Uno Digital Pin 9
-#define Y_LIMIT_BIT     2  // Uno Digital Pin 10
-#define Z_LIMIT_BIT     3  // Uno Digital Pin 11
-#define LIMIT_INT       PCIE0  // Pin change interrupt enable pin
-#define LIMIT_INT_vect  PCINT0_vect 
-#define LIMIT_PCMSK     PCMSK0 // Pin change interrupt register
-#define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
-
-#define SPINDLE_ENABLE_DDR   DDRB
-#define SPINDLE_ENABLE_PORT  PORTB
-#define SPINDLE_ENABLE_BIT   4  // Uno Digital Pin 12
-
-#define SPINDLE_DIRECTION_DDR   DDRB
-#define SPINDLE_DIRECTION_PORT  PORTB
-#define SPINDLE_DIRECTION_BIT   5  // Uno Digital Pin 13 (NOTE: D13 can't be pulled-high input due to LED.)
-
-#define COOLANT_FLOOD_DDR   DDRC
-#define COOLANT_FLOOD_PORT  PORTC
-#define COOLANT_FLOOD_BIT   3  // Uno Analog Pin 3
-
-// NOTE: Uno analog pins 4 and 5 are reserved for an i2c interface, and may be installed at
-// a later date if flash and memory space allows.
-// #define ENABLE_M7  // Mist coolant disabled by default. Uncomment to enable.
-#ifdef ENABLE_M7
-  #define COOLANT_MIST_DDR   DDRC
-  #define COOLANT_MIST_PORT  PORTC
-  #define COOLANT_MIST_BIT   4 // Uno Analog Pin 4
-#endif  
-
-// NOTE: All pinouts pins must be on the same port
-#define PINOUT_DDR       DDRC
-#define PINOUT_PIN       PINC
-#define PINOUT_PORT      PORTC
-#define PIN_RESET        0  // Uno Analog Pin 0
-#define PIN_FEED_HOLD    1  // Uno Analog Pin 1
-#define PIN_CYCLE_START  2  // Uno Analog Pin 2
-#define PINOUT_INT       PCIE1  // Pin change interrupt enable pin
-#define PINOUT_INT_vect  PCINT1_vect
-#define PINOUT_PCMSK     PCMSK1 // Pin change interrupt register
-#define PINOUT_MASK ((1<<PIN_RESET)|(1<<PIN_FEED_HOLD)|(1<<PIN_CYCLE_START))
diff --git a/nuts_bolts.h b/nuts_bolts.h
index 65bdbe2..fed0f45 100644
--- a/nuts_bolts.h
+++ b/nuts_bolts.h
@@ -27,6 +27,7 @@
 #include <stdbool.h>
 #include "config.h"
 #include "defaults.h"
+#include "pin_map.h"
 
 #define false 0
 #define true 1
diff --git a/pin_map.h b/pin_map.h
new file mode 100644
index 0000000..0b7b5d1
--- /dev/null
+++ b/pin_map.h
@@ -0,0 +1,181 @@
+/*
+  pin_map.h - Pin mapping configuration file
+  Part of Grbl
+
+  Copyright (c) 2013 Sungeun K. Jeon
+
+  Grbl is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  Grbl is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* The pin_map.h file serves as a central pin mapping settings file for different processor
+   types, i.e. AVR 328p or AVR Mega 2560. Grbl officially supports the Arduino Uno, but the 
+   other supplied pin mappings are supplied by users, so your results may vary. */
+
+#ifndef pin_map_h
+#define pin_map_h
+
+#ifdef ARDUINO_UNO // AVR 328p, Officially supported by Grbl.
+
+  // Serial port pins
+  #define Serial_RX_vect USART_RX_vect
+  #define Serial_UDRE_vect USART_UDRE_vect
+
+  // NOTE: All step bit and direction pins must be on the same port.
+  #define STEPPING_DDR       DDRD
+  #define STEPPING_PORT      PORTD
+  #define X_STEP_BIT         2  // Uno Digital Pin 2
+  #define Y_STEP_BIT         3  // Uno Digital Pin 3
+  #define Z_STEP_BIT         4  // Uno Digital Pin 4
+  #define X_DIRECTION_BIT    5  // Uno Digital Pin 5
+  #define Y_DIRECTION_BIT    6  // Uno Digital Pin 6
+  #define Z_DIRECTION_BIT    7  // Uno Digital Pin 7
+  #define STEP_MASK ((1<<X_STEP_BIT)|(1<<Y_STEP_BIT)|(1<<Z_STEP_BIT)) // All step bits
+  #define DIRECTION_MASK ((1<<X_DIRECTION_BIT)|(1<<Y_DIRECTION_BIT)|(1<<Z_DIRECTION_BIT)) // All direction bits
+  #define STEPPING_MASK (STEP_MASK | DIRECTION_MASK) // All stepping-related bits (step/direction)
+
+  #define STEPPERS_DISABLE_DDR    DDRB
+  #define STEPPERS_DISABLE_PORT   PORTB
+  #define STEPPERS_DISABLE_BIT    0  // Uno Digital Pin 8
+  #define STEPPERS_DISABLE_MASK (1<<STEPPERS_DISABLE_BIT)
+
+  // NOTE: All limit bit pins must be on the same port
+  #define LIMIT_DDR       DDRB
+  #define LIMIT_PIN       PINB
+  #define LIMIT_PORT      PORTB
+  #define X_LIMIT_BIT     1  // Uno Digital Pin 9
+  #define Y_LIMIT_BIT     2  // Uno Digital Pin 10
+  #define Z_LIMIT_BIT     3  // Uno Digital Pin 11
+  #define LIMIT_INT       PCIE0  // Pin change interrupt enable pin
+  #define LIMIT_INT_vect  PCINT0_vect 
+  #define LIMIT_PCMSK     PCMSK0 // Pin change interrupt register
+  #define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
+
+  #define SPINDLE_ENABLE_DDR   DDRB
+  #define SPINDLE_ENABLE_PORT  PORTB
+  #define SPINDLE_ENABLE_BIT   4  // Uno Digital Pin 12
+
+  #define SPINDLE_DIRECTION_DDR   DDRB
+  #define SPINDLE_DIRECTION_PORT  PORTB
+  #define SPINDLE_DIRECTION_BIT   5  // Uno Digital Pin 13 (NOTE: D13 can't be pulled-high input due to LED.)
+
+  #define COOLANT_FLOOD_DDR   DDRC
+  #define COOLANT_FLOOD_PORT  PORTC
+  #define COOLANT_FLOOD_BIT   3  // Uno Analog Pin 3
+
+  // NOTE: Uno analog pins 4 and 5 are reserved for an i2c interface, and may be installed at
+  // a later date if flash and memory space allows.
+  // #define ENABLE_M7  // Mist coolant disabled by default. Uncomment to enable.
+  #ifdef ENABLE_M7
+    #define COOLANT_MIST_DDR   DDRC
+    #define COOLANT_MIST_PORT  PORTC
+    #define COOLANT_MIST_BIT   4 // Uno Analog Pin 4
+  #endif  
+
+  // NOTE: All pinouts pins must be on the same port
+  #define PINOUT_DDR       DDRC
+  #define PINOUT_PIN       PINC
+  #define PINOUT_PORT      PORTC
+  #define PIN_RESET        0  // Uno Analog Pin 0
+  #define PIN_FEED_HOLD    1  // Uno Analog Pin 1
+  #define PIN_CYCLE_START  2  // Uno Analog Pin 2
+  #define PINOUT_INT       PCIE1  // Pin change interrupt enable pin
+  #define PINOUT_INT_vect  PCINT1_vect
+  #define PINOUT_PCMSK     PCMSK1 // Pin change interrupt register
+  #define PINOUT_MASK ((1<<PIN_RESET)|(1<<PIN_FEED_HOLD)|(1<<PIN_CYCLE_START))
+  
+#endif
+
+
+#ifdef ARDUINO_MEGA_2560 // Unsupported. Doesn't work. Supplied by @elmom.
+
+  // Serial port pins
+  #define Serial_RX_vect USART0_RX_vect
+  #define Serial_UDRE_vect USART0_UDRE_vect
+
+  // NOTE: All step bit and direction pins must be on the same port.
+  #define STEPPING_DDR      DDRA
+  #define STEPPING_PORT     PORTA
+  #define STEPPING_PIN      PINA
+  #define X_STEP_BIT        0 // MEGA2560 Digital Pin 22
+  #define Y_STEP_BIT        1 // MEGA2560 Digital Pin 23
+  #define Z_STEP_BIT        2 // MEGA2560 Digital Pin 24
+  // #define C_STEP_BIT        3 // MEGA2560 Digital Pin 25
+  #define X_DIRECTION_BIT   4 // MEGA2560 Digital Pin 26
+  #define Y_DIRECTION_BIT   5 // MEGA2560 Digital Pin 27
+  #define Z_DIRECTION_BIT   6 // MEGA2560 Digital Pin 28
+  // #define C_DIRECTION_BIT   7 // MEGA2560 Digital Pin 29
+  #define STEP_MASK ((1<<X_STEP_BIT)|(1<<Y_STEP_BIT)|(1<<Z_STEP_BIT)) // All step bits
+  #define DIRECTION_MASK ((1<<X_DIRECTION_BIT)|(1<<Y_DIRECTION_BIT)|(1<<Z_DIRECTION_BIT)) // All direction bits
+  #define STEPPING_MASK (STEP_MASK | DIRECTION_MASK) // All stepping-related bits (step/direction)
+
+  #define STEPPERS_DISABLE_DDR   DDRC
+  #define STEPPERS_DISABLE_PORT  PORTC
+  #define STEPPERS_DISABLE_BIT   7 // MEGA2560 Digital Pin 30
+  #define STEPPERS_DISABLE_MASK (1<<STEPPERS_DISABLE_BIT)
+
+  // NOTE: All limit bit pins must be on the same port
+  #define LIMIT_DDR       DDRC
+  #define LIMIT_PORT      PORTC
+  #define LIMIT_PIN       PINC
+  #define X_LIMIT_BIT     6 // MEGA2560 Digital Pin 31
+  #define Y_LIMIT_BIT     5 // MEGA2560 Digital Pin 32
+  #define Z_LIMIT_BIT     4 // MEGA2560 Digital Pin 33
+  // #define C_LIMIT_BIT     3 // MEGA2560 Digital Pin 34
+  #define LIMIT_INT       PCIE0  // Pin change interrupt enable pin
+  #define LIMIT_INT_vect  PCINT0_vect 
+  #define LIMIT_PCMSK     PCMSK0 // Pin change interrupt register
+  #define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
+
+  #define SPINDLE_ENABLE_DDR   DDRC
+  #define SPINDLE_ENABLE_PORT  PORTC
+  #define SPINDLE_ENABLE_BIT   2 // MEGA2560 Digital Pin 35
+
+  #define SPINDLE_DIRECTION_DDR   DDRC
+  #define SPINDLE_DIRECTION_PORT  PORTC
+  #define SPINDLE_DIRECTION_BIT   1 // MEGA2560 Digital Pin 36
+
+  #define COOLANT_FLOOD_DDR   DDRC
+  #define COOLANT_FLOOD_PORT  PORTC
+  #define COOLANT_FLOOD_BIT   0 // MEGA2560 Digital Pin 37
+
+  // #define ENABLE_M7  // Mist coolant disabled by default. Uncomment to enable.
+  #ifdef ENABLE_M7
+    #define COOLANT_MIST_DDR   DDRC
+    #define COOLANT_MIST_PORT  PORTC
+    #define COOLANT_MIST_BIT   0 // MEGA2560 Digital Pin 37
+  #endif  
+
+  // NOTE: All pinouts pins must be on the same port
+  #define PINOUT_DDR       DDRC
+  #define PINOUT_PIN       PINC
+  #define PINOUT_PORT      PORTC
+  #define PIN_RESET        0  // Uno Analog Pin 0
+  #define PIN_FEED_HOLD    1  // Uno Analog Pin 1
+  #define PIN_CYCLE_START  2  // Uno Analog Pin 2
+  #define PINOUT_INT       PCIE1  // Pin change interrupt enable pin
+  #define PINOUT_INT_vect  PCINT1_vect
+  #define PINOUT_PCMSK     PCMSK1 // Pin change interrupt register
+  #define PINOUT_MASK ((1<<PIN_RESET)|(1<<PIN_FEED_HOLD)|(1<<PIN_CYCLE_START))
+
+#endif
+
+/* 
+#ifdef CUSTOM_PROC
+  // For a custom pin map or different processor, copy and paste one of the default pin map
+  // settings above and modify it to your needs. Then, make sure the defined name is also
+  // changed in the config.h file.
+#endif
+*/
+
+#endif
diff --git a/serial.h b/serial.h
index 79ffb7e..723d48f 100644
--- a/serial.h
+++ b/serial.h
@@ -27,20 +27,6 @@
 
 #include "nuts_bolts.h"
 
-#if defined(USART_RX_vect) // For atmega328p (Arduino Uno) etc.
-#define Serial_RX_vect USART_RX_vect
-#define Serial_UDRE_vect USART_UDRE_vect
-#elif defined(USART0_RX_vect) // For atmega644p, atmega1280 and atmega2560 (ArduinoMEGA) etc.
-#define Serial_RX_vect USART0_RX_vect
-#define Serial_UDRE_vect USART0_UDRE_vect
-#elif defined(USART_RXC_vect) // For some odd chips
-#define Serial_RX_vect USART_RXC_vect
-#define Serial_UDRE_vect USART_UDRE_vect
-#elif defined(USART1_RX_vect)// Some AVRs have 1 USB and a single USART (USART1), though the USB is often preffered for serial comms (like Arduino Leonardo etc.)
-#define Serial1_RX_vect USART1_RX_vect
-#define Serial1_UDRE_vect USART1_UDRE_vect
-#endif
-
 #ifndef RX_BUFFER_SIZE
   #define RX_BUFFER_SIZE 128
 #endif