diff --git a/.gitignore b/.gitignore
index 1102503..a764af3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 *.hex
 *.o
-*.elf
\ No newline at end of file
+*.elf
+.DS_Store
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 90742cc..ab41f34 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,7 @@ DEVICE     = atmega328p
 CLOCK      = 16000000
 PROGRAMMER = -c avrisp2 -P usb
 OBJECTS    = main.o motion_control.o gcode.o spindle_control.o wiring_serial.o serial_protocol.o stepper.o \
-             eeprom.o config.o
+             eeprom.o config.o accelleration.o
 # FUSES      = -U hfuse:w:0xd9:m -U lfuse:w:0x24:m
 FUSES      = -U hfuse:w:0xd2:m -U lfuse:w:0xff:m
 
diff --git a/accelleration.h b/accelleration.h
new file mode 100644
index 0000000..ab73d6d
--- /dev/null
+++ b/accelleration.h
@@ -0,0 +1,51 @@
+/*
+  accelleration.h - accelleration management support 
+  Part of Grbl
+
+  Copyright (c) 2009 Simen Svale Skogsrud
+
+  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/>.
+*/
+
+#ifndef accelleration_h
+#define accelleration_h 
+
+// Unless someone else defined AC_TICKS_PER_SECOND, we define a sensible default
+#ifndef AC_TICKS_PER_SECOND
+#define AC_TICKS_PER_SECOND 10
+#endif
+
+struct AccellerationProfile {
+  float initial_scaler;
+  float final_scaler;
+  float accelleration_delta;
+  float decelleration_delta;
+  uint32_t accellerate_ticks;
+  uint32_t plateau_ticks;    
+};
+
+struct AccellerationProfileSegment {
+  float v_entry[3];
+  float v_ideal[3];
+  float v_exit[3];
+  float distance;
+  float f_entry, f_exit;
+};
+
+struct AccellerationProfileBuilder {
+  AccellerationProfileSegment segment[3];
+  uint8_t current;
+};
+
+#endif 
\ No newline at end of file
diff --git a/config.c b/config.c
index e8af99d..13be1de 100644
--- a/config.c
+++ b/config.c
@@ -32,11 +32,19 @@ void reset_settings() {
   settings.steps_per_mm[2] = Z_STEPS_PER_MM;
   settings.pulse_microseconds = STEP_PULSE_MICROSECONDS;
   settings.default_feed_rate = DEFAULT_FEEDRATE;
+<<<<<<< Updated upstream
   settings.default_seek_rate = RAPID_FEEDRATE;
   settings.dead_feed_rate = DEFAULT_FEEDRATE/5;
   settings.acceleration = DEFAULT_FEEDRATE/100;
   settings.mm_per_arc_segment = MM_PER_ARC_SEGMENT;
   settings.invert_mask = STEPPING_INVERT_MASK;
+=======
+  settings.seek_rate = DEFAULT_SEEKRATE;
+  settings.mm_per_arc_segment = DEFAULT_MM_PER_ARC_SEGMENT;
+  settings.invert_mask = 0;
+  settings.max_jerk = DEFAULT_MAX_JERK;
+  settings.accelleration = DEFAULT_ACCELLERATION;
+>>>>>>> Stashed changes
 }
 
 void dump_settings() {
@@ -51,7 +59,10 @@ void dump_settings() {
   printPgmString(PSTR(" (mm/sec^2 max acceleration)\r\n$9 = ")); printFloat(settings.acceleration);
   printPgmString(PSTR(" (mm/arc segment)\r\n$10 = ")); printInteger(settings.invert_mask); 
   printPgmString(PSTR(" (step port invert mask. binary = ")); printIntegerInBase(settings.invert_mask, 2);  
-  printPgmString(PSTR(")\r\n\r\n'$x=value' to set parameter or just '$' to dump current settings\r\n"));
+  printPgmString(PSTR(")\n\r$8 = ")); printFloat(settings.max_jerk);
+  printPgmString(PSTR(" (max jerk in delta mm/second)\r\n$9 = ")); printFloat(settings.accelleration); 
+  printPgmString(PSTR(" (accelleration in mm/second^2)"));
+  printPgmString(PSTR("\r\n'$x=value' to set parameter or just '$' to dump current settings\r\n"));
 }
 
 int read_settings() {
@@ -77,11 +88,19 @@ void store_setting(int parameter, double value) {
     settings.steps_per_mm[parameter] = value; break;
     case 3: settings.pulse_microseconds = round(value); break;
     case 4: settings.default_feed_rate = value; break;
+<<<<<<< Updated upstream
     case 5: settings.default_seek_rate = value; break;
     case 6: settings.dead_feed_rate = value; break;
     case 8: settings.mm_per_arc_segment = value; break;
     case 9: settings.acceleration = value; break;
     case 10: settings.invert_mask = trunc(value); break;
+=======
+    case 5: settings.seek_rate = value; break;
+    case 6: settings.mm_per_arc_segment = value; break;
+    case 7: settings.invert_mask = trunc(value); break;
+    case 8: settings.max_jerk = value; break;
+    case 9: settings.accelleration = fabs(value); break;
+>>>>>>> Stashed changes
     default: 
     printPgmString(PSTR("Unknown parameter\r\n"));
     return;
diff --git a/config.h b/config.h
index 68ac922..1e3d79b 100644
--- a/config.h
+++ b/config.h
@@ -22,6 +22,8 @@
 #define config_h
 
 #define VERSION "0.51"
+#include <math.h>
+#include <inttypes.h>
 
 // Settings that can only be set at compile-time:
 
@@ -69,6 +71,10 @@ struct Settings {
   double default_seek_rate;
   uint8_t invert_mask;
   double mm_per_arc_segment;
+<<<<<<< Updated upstream
+=======
+  double max_jerk;
+>>>>>>> Stashed changes
   double accelleration;
 };
 struct Settings settings;
@@ -94,6 +100,8 @@ void store_setting(int parameter, double value);
 
 #define RAPID_FEEDRATE 480.0 // in millimeters per minute
 #define DEFAULT_FEEDRATE 480.0
+#define DEFAULT_MAX_JERK 10.0
+#define DEFAULT_ACCELLERATION 0.1
 
 // Use this line for default operation (step-pulses high)
 #define STEPPING_INVERT_MASK 0
diff --git a/nuts_bolts.h b/nuts_bolts.h
index f27f4c6..cc6664d 100644
--- a/nuts_bolts.h
+++ b/nuts_bolts.h
@@ -41,4 +41,10 @@
 #define Y_AXIS 1
 #define Z_AXIS 2
 
+void scale_vector(float *target, float *source, float multiplier) {
+  target[0] = source[0]*multiplier;
+  target[1] = source[1]*multiplier;
+  target[2] = source[2]*multiplier;
+}
+
 #endif
diff --git a/stepper.c b/stepper.c
index e6a1f99..603ab89 100644
--- a/stepper.c
+++ b/stepper.c
@@ -40,6 +40,7 @@
 #define LINE_BUFFER_SIZE 10
 #endif
 
+<<<<<<< Updated upstream
 struct Line {
   uint32_t steps_x, steps_y, steps_z;
   int32_t maximum_steps;
@@ -75,6 +76,41 @@ void update_accelleration_plan() {
   int initial_buffer_tail = line_buffer_tail;
   
 }
+=======
+#define ENABLE_STEPPER_DRIVER_INTERRUPT()  TIMSK1 |= (1<<OCIE1A)
+#define DISABLE_STEPPER_DRIVER_INTERRUPT() TIMSK1 &= ~(1<<OCIE1A)
+
+#define CYCLES_PER_ACCELLERATION_TICK (F_CPU)
+
+// This record is used to buffer the setup for each linear movement
+struct Block {
+  uint32_t steps_x, steps_y, steps_z; // Step count along each axis
+  double  rate_x, rate_y, rate_z;     // Nominal steps/minute for each axis
+  int32_t  maximum_steps;             // The largest stepcount of any axis for this block
+  uint8_t  direction_bits;            // The direction bit set for this block (refers to *_DIRECTION_BIT in config.h)
+  uint32_t rate;                      // The nominal step rate for this block in microseconds/step
+};
+
+struct Block block_buffer[BLOCK_BUFFER_SIZE]; // A buffer for motion instructions
+volatile int block_buffer_head = 0;           // Index of the next block to be pushed
+volatile int block_buffer_tail = 0;           // Index of the block to process now
+
+// Variables used by The Stepper Driver Interrupt
+uint8_t out_bits;               // The next stepping-bits to be output
+struct Block *current_block;    // A pointer to the block currently being traced
+int32_t counter_x, 
+        counter_y, 
+        counter_z;              // counter variables for the bresenham line tracer
+uint32_t iterations;            // The number of iterations left to complete the current_block
+volatile int busy;              // TRUE when SIG_OUTPUT_COMPARE1A is being serviced. Used to avoid retriggering that handler.
+
+// Variables used by the accelleration manager
+float rate_multiplier;          // The current rate multiplier. at 1.0 nominal rates equals actual rates
+float rate_change_rate;         // The amount the rate_multiplier changes each 
+uint32_t rate_ramp_iterations;  // The accelleration iterations for which the current rate ramp is valid
+
+void config_step_timer(uint32_t microseconds);
+>>>>>>> Stashed changes
 
 // Add a new linear movement to the buffer. steps_x, _y and _z is the signed, relative motion in 
 // steps. Microseconds specify how many microseconds the move should take to perform. To aid accelleration
@@ -83,6 +119,7 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
   // Calculate the buffer head after we push this byte
 	int next_buffer_head = (line_buffer_head + 1) % LINE_BUFFER_SIZE;	
 	// If the buffer is full: good! That means we are well ahead of the robot. 
+<<<<<<< Updated upstream
 	// Nap until there is room in the buffer.
   while(line_buffer_tail == next_buffer_head) { sleep_mode(); }
   // Setup line record
@@ -94,6 +131,26 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
   // Bail if this is a zero-length line
   if (line->maximum_steps == 0) { return; };
   line->rate = (TICKS_PER_MICROSECOND*microseconds)/line->maximum_steps;
+=======
+	// Rest here until there is room in the buffer.
+  while(block_buffer_tail == next_buffer_head) { sleep_mode(); }
+  // Prepare to set up new block
+  struct Block *block = &block_buffer[block_buffer_head];
+  // Number of steps for each axis
+  block->steps_x = labs(steps_x);
+  block->steps_y = labs(steps_y);
+  block->steps_z = labs(steps_z);
+  block->maximum_steps = max(block->steps_x, max(block->steps_y, block->steps_z));
+  // Bail if this is a zero-length block
+  if (block->maximum_steps == 0) { return; };
+  // Rate in steps/second for each axis
+  double rate_multiplier = 60.0*1000000.0/microseconds;
+  block->rate_x = round(block->steps_x*rate_multiplier);
+  block->rate_y = round(block->steps_y*rate_multiplier);
+  block->rate_z = round(block->steps_z*rate_multiplier);
+  block->rate = microseconds/block->maximum_steps;
+  // Compute direction bits for this block
+>>>>>>> Stashed changes
   uint8_t direction_bits = 0;
   if (steps_x < 0) { direction_bits |= (1<<X_DIRECTION_BIT); }
   if (steps_y < 0) { direction_bits |= (1<<Y_DIRECTION_BIT); }
@@ -101,6 +158,7 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
   line->direction_bits = direction_bits;
   line->average_millimeters_per_step_event = millimeters/line->maximum_steps
   // Move buffer head
+<<<<<<< Updated upstream
   line_buffer_head = next_buffer_head;
   // enable stepper interrupt
 	TIMSK1 |= (1<<OCIE1A);
@@ -110,6 +168,16 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
 // This timer interrupt is executed at the rate set with config_step_timer. It pops one instruction from
 // the line_buffer, executes it. Then it starts timer2 in order to reset the motor port after
 // five microseconds.
+=======
+  block_buffer_head = next_buffer_head;
+  // Ensure that block processing is running by enabling The Stepper Driver Interrupt
+  ENABLE_STEPPER_DRIVER_INTERRUPT();
+}
+
+// "The Stepper Driver Interrupt" - This timer interrupt is the workhorse of Grbl. It is  executed at the rate set with
+// config_step_timer. It pops blocks from the block_buffer and executes them by pulsing the stepper pins appropriately. 
+// It is supported by The Stepper Port Reset Interrupt which it uses to reset the stepper port after each pulse.
+>>>>>>> Stashed changes
 #ifdef TIMER1_COMPA_vect
 SIGNAL(TIMER1_COMPA_vect)
 #else
@@ -123,7 +191,7 @@ SIGNAL(SIG_OUTPUT_COMPARE1A)
   STEPPING_PORT = (STEPPING_PORT & ~DIRECTION_MASK) | (out_bits & DIRECTION_MASK);
   // Then pulse the stepping pins
   STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | out_bits;
-  // Reset step pulse reset timer so that SIG_OVERFLOW2 can reset the signal after
+  // Reset step pulse reset timer so that The Stepper Port Reset Interrupt can reset the signal after
   // exactly settings.pulse_microseconds microseconds.
   TCNT2 = -(((settings.pulse_microseconds-2)*TICKS_PER_MICROSECOND)/8);
 
@@ -222,7 +290,7 @@ void st_init()
   TCCR2B = (1<<CS21); // Full speed, 1/8 prescaler
   TIMSK2 |= (1<<TOIE2);      
   
-  // Just ste the step_timer to something serviceably lazy
+  // Just set the step_timer to something serviceably lazy
   config_step_timer(20000);
   // set enable pin     
   STEPPERS_ENABLE_PORT |= 1<<STEPPERS_ENABLE_BIT;