Added runtime configurable global settings with eeprom persitence

Makefile

@@ -30,8 +30,10 @@
 DEVICE     = atmega168
 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 
+OBJECTS    = main.o motion_control.o gcode.o spindle_control.o wiring_serial.o serial_protocol.o stepper.o \
-FUSES      = -U hfuse:w:0xd9:m -U lfuse:w:0x24:m
+             eeprom.o config.o
+# FUSES      = -U hfuse:w:0xd9:m -U lfuse:w:0x24:m
+FUSES      = -U hfuse:w:0xd2:m -U lfuse:w:0xff:m
 
 # Tune the lines below only if you know what you are doing:
 

config.c

@@ -0,0 +1,95 @@
+/*
+  config.c - eeprom and compile time configuration handling 
+  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/>.
+*/
+
+#include <avr/io.h>
+#include <math.h>
+#include "nuts_bolts.h"
+#include "config.h"
+#include "eeprom.h"
+#include "wiring_serial.h"
+
+void reset_settings() {
+  settings.steps_per_mm[0] = X_STEPS_PER_MM;
+  settings.steps_per_mm[1] = Y_STEPS_PER_MM;
+  settings.steps_per_mm[2] = Z_STEPS_PER_MM;
+  settings.pulse_microseconds = STEP_PULSE_MICROSECONDS;
+  settings.default_feed_rate = DEFAULT_FEEDRATE;
+  settings.default_seek_rate = RAPID_FEEDRATE;
+  settings.mm_per_arc_segment = MM_PER_ARC_SEGMENT;
+  settings.invert_mask = STEPPING_INVERT_MASK;
+}
+
+void dump_settings() {
+  printString("$0 = "); printFloat(settings.steps_per_mm[0]);
+  printString(" (steps/mm x)\r\n$1 = "); printFloat(settings.steps_per_mm[1]);
+  printString(" (steps/mm y)\r\n$2 = "); printFloat(settings.steps_per_mm[2]);
+  printString(" (steps/mm z)\r\n$3 = "); printInteger(settings.pulse_microseconds);
+  printString(" (microseconds step pulse)\r\n$4 = "); printFloat(settings.default_feed_rate);
+  printString(" (mm/sec default feed rate)\r\n$5 = "); printFloat(settings.default_seek_rate);
+  printString(" (mm/sec default seek rate)\r\n$6 = "); printFloat(settings.mm_per_arc_segment);
+  printString(" (mm/arc segment)\r\n$7 = "); printInteger(settings.invert_mask); 
+  printString(" (step port invert mask. binary = "); printIntegerInBase(settings.invert_mask, 2);  
+  printString(")\r\n\r\n'$x=value' to set parameter or just '$' to dump current settings\r\n");
+}
+
+int read_settings() {
+  // Check version-byte of eeprom
+  uint8_t version = eeprom_get_char(0);  
+  if (version != SETTINGS_VERSION) { return(FALSE); }
+  // Read settings-record and check checksum
+  if (!(memcpy_from_eeprom_with_checksum((char*)&settings, 1, sizeof(struct Settings)))) {
+    return(FALSE);
+  }
+  return(TRUE);
+}
+
+void write_settings() {
+  eeprom_put_char(0, SETTINGS_VERSION);
+  memcpy_to_eeprom_with_checksum(1, (char*)&settings, sizeof(struct Settings));
+}
+
+// A helper method to set settings from command line
+void store_setting(int parameter, double value) {
+  switch(parameter) {
+    case 0: case 1: case 2:
+    settings.steps_per_mm[parameter] = value; break;
+    case 3: settings.pulse_microseconds = round(value); break;
+    case 4: settings.default_feed_rate = value; break;
+    case 5: settings.default_seek_rate = value; break;
+    case 6: settings.mm_per_arc_segment = value; break;
+    case 7: settings.invert_mask = trunc(value); break;
+    default: 
+    printString("Unknown parameter\r\n");
+    return;
+  }
+  write_settings();
+  printString("Stored new setting\r\n");
+}
+
+void config_init() {
+  if(read_settings()) {
+    printString("'$' to dump current settings\r\n");
+  } else {
+    printString("EEPROM blank. Rewrote default settings:\r\n");
+    reset_settings();
+    write_settings();
+    dump_settings();
+  }
+}

config.h

@@ -1,5 +1,5 @@
 /*
-  config.h - configuration data for Grbl
+  config.h - eeprom and compile time configuration handling 
   Part of Grbl
 
   Copyright (c) 2009 Simen Svale Skogsrud
@@ -21,22 +21,11 @@
 #ifndef config_h
 #define config_h
 
-#define VERSION "0.5"
+#define VERSION "0.51"
 
-#define MICROSTEPS 8
+// Settings that can only be set at compile-time:
-#define X_STEPS_PER_MM (94.488188976378*MICROSTEPS)
-#define Y_STEPS_PER_MM (94.488188976378*MICROSTEPS)
-#define Z_STEPS_PER_MM (94.488188976378*MICROSTEPS)
 
-#define STEP_PULSE_MICROSECONDS 30
+#define BAUD_RATE 9600
-
-#define INCHES_PER_MM (1.0/25.4)
-#define X_STEPS_PER_INCH X_STEPS_PER_MM*INCHES_PER_MM
-#define Y_STEPS_PER_INCH Y_STEPS_PER_MM*INCHES_PER_MM
-#define Z_STEPS_PER_INCH Z_STEPS_PER_MM*INCHES_PER_MM
-
-#define RAPID_FEEDRATE 480.0 // in millimeters per minute
-#define DEFAULT_FEEDRATE 480.0
 
 #define STEPPERS_ENABLE_DDR     DDRD
 #define STEPPERS_ENABLE_PORT    PORTD
@@ -65,14 +54,44 @@
 #define SPINDLE_DIRECTION_PORT PORTD
 #define SPINDLE_DIRECTION_BIT 7
 
+
+// Version of the EEPROM data. Will be used to migrate existing data from older versions of Grbl
+// when firmware is upgraded. Always stored in byte 0 of eeprom
+#define SETTINGS_VERSION 1
+
+// Current global settings (persisted in EEPROM from byte 1 onwards)
+struct Settings {
+  double steps_per_mm[3];
+  uint8_t microsteps;
+  uint8_t pulse_microseconds;
+  double default_feed_rate;
+  double default_seek_rate;
+  uint8_t invert_mask;
+  double mm_per_arc_segment;
+};
+struct Settings settings;
+
+// Initialize the configuration subsystem (load settings from EEPROM)
+void config_init();
+
+// Print current settings
+void dump_settings();
+
+// A helper method to set new settings from command line
+void store_setting(int parameter, double value);
+
+
+// Default settings (used when resetting eeprom-settings)
+#define MICROSTEPS 8
+#define X_STEPS_PER_MM (94.488188976378*MICROSTEPS)
+#define Y_STEPS_PER_MM (94.488188976378*MICROSTEPS)
+#define Z_STEPS_PER_MM (94.488188976378*MICROSTEPS)
+#define STEP_PULSE_MICROSECONDS 30
+
 #define MM_PER_ARC_SEGMENT 0.1
 
-#define BAUD_RATE 9600
+#define RAPID_FEEDRATE 480.0 // in millimeters per minute
-
+#define DEFAULT_FEEDRATE 480.0
-#define STEP_MASK ((1<<X_STEP_BIT)|(1<<Y_STEP_BIT)|(1<<Z_STEP_BIT))
-#define DIRECTION_MASK ((1<<X_DIRECTION_BIT)|(1<<Y_DIRECTION_BIT)|(1<<Z_DIRECTION_BIT))
-#define STEPPING_MASK (STEP_MASK | DIRECTION_MASK)
-#define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT))
 
 // Use this line for default operation (step-pulses high)
 #define STEPPING_INVERT_MASK 0
@@ -83,4 +102,13 @@
 // Or bake your own like this adding any step-bits or directions you want to invert:
 // #define STEPPING_INVERT_MASK (STEP_MASK | (1<<X_DIRECTION_BIT) | (1<<Y_DIRECTION_BIT))
 
+
+// Some useful constants
+#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 LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
+
+#define INCHES_PER_MM (1.0/25.4) // A conversion rate
+
 #endif

eeprom.c

@@ -0,0 +1,148 @@
+// This file has been prepared for Doxygen automatic documentation generation.
+/*! \file ********************************************************************
+*
+* Atmel Corporation
+*
+* \li File:               eeprom.c
+* \li Compiler:           IAR EWAAVR 3.10c
+* \li Support mail:       avr@atmel.com
+*
+* \li Supported devices:  All devices with split EEPROM erase/write
+*                         capabilities can be used.
+*                         The example is written for ATmega48.
+*
+* \li AppNote:            AVR103 - Using the EEPROM Programming Modes.
+*
+* \li Description:        Example on how to use the split EEPROM erase/write
+*                         capabilities in e.g. ATmega48. All EEPROM
+*                         programming modes are tested, i.e. Erase+Write,
+*                         Erase-only and Write-only.
+*
+*                         $Revision: 1.6 $
+*                         $Date: Friday, February 11, 2005 07:16:44 UTC $
+****************************************************************************/
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+/* These EEPROM bits have different names on different devices. */
+#ifndef EEPE
+		#define EEPE  EEWE  //!< EEPROM program/write enable.
+		#define EEMPE EEMWE //!< EEPROM master program/write enable.
+#endif
+
+/* These two are unfortunately not defined in the device include files. */
+#define EEPM1 5 //!< EEPROM Programming Mode Bit 1.
+#define EEPM0 4 //!< EEPROM Programming Mode Bit 0.
+
+/* Define to reduce code size. */
+#define EEPROM_IGNORE_SELFPROG //!< Remove SPM flag polling.
+
+/*! \brief  Read byte from EEPROM.
+ *
+ *  This function reads one byte from a given EEPROM address.
+ *
+ *  \note  The CPU is halted for 4 clock cycles during EEPROM read.
+ *
+ *  \param  addr  EEPROM address to read from.
+ *  \return  The byte read from the EEPROM address.
+ */
+unsigned char eeprom_get_char( unsigned int addr )
+{
+	do {} while( EECR & (1<<EEPE) ); // Wait for completion of previous write.
+	EEAR = addr; // Set EEPROM address register.
+	EECR = (1<<EERE); // Start EEPROM read operation.
+	return EEDR; // Return the byte read from EEPROM.
+}
+
+/*! \brief  Write byte to EEPROM.
+ *
+ *  This function writes one byte to a given EEPROM address.
+ *  The differences between the existing byte and the new value is used
+ *  to select the most efficient EEPROM programming mode.
+ *
+ *  \note  The CPU is halted for 2 clock cycles during EEPROM programming.
+ *
+ *  \note  When this function returns, the new EEPROM value is not available
+ *         until the EEPROM programming time has passed. The EEPE bit in EECR
+ *         should be polled to check whether the programming is finished.
+ *
+ *  \note  The EEPROM_GetChar() function checks the EEPE bit automatically.
+ *
+ *  \param  addr  EEPROM address to write to.
+ *  \param  new_value  New EEPROM value.
+ */
+void eeprom_put_char( unsigned int addr, unsigned char new_value )
+{
+	char old_value; // Old EEPROM value.
+	char diff_mask; // Difference mask, i.e. old value XOR new value.
+
+	cli(); // Ensure atomic operation for the write operation.
+	
+	do {} while( EECR & (1<<EEPE) ); // Wait for completion of previous write.
+	#ifndef EEPROM_IGNORE_SELFPROG
+	do {} while( SPMCSR & (1<<SELFPRGEN) ); // Wait for completion of SPM.
+	#endif
+	
+	EEAR = addr; // Set EEPROM address register.
+	EECR = (1<<EERE); // Start EEPROM read operation.
+	old_value = EEDR; // Get old EEPROM value.
+	diff_mask = old_value ^ new_value; // Get bit differences.
+	
+	// Check if any bits are changed to '1' in the new value.
+	if( diff_mask & new_value ) {
+		// Now we know that _some_ bits need to be erased to '1'.
+		
+		// Check if any bits in the new value are '0'.
+		if( new_value != 0xff ) {
+			// Now we know that some bits need to be programmed to '0' also.
+			
+			EEDR = new_value; // Set EEPROM data register.
+			EECR = (1<<EEMPE) | // Set Master Write Enable bit...
+			       (0<<EEPM1) | (0<<EEPM0); // ...and Erase+Write mode.
+			EECR |= (1<<EEPE);  // Start Erase+Write operation.
+		} else {
+			// Now we know that all bits should be erased.
+
+			EECR = (1<<EEMPE) | // Set Master Write Enable bit...
+			       (1<<EEPM0);  // ...and Erase-only mode.
+			EECR |= (1<<EEPE);  // Start Erase-only operation.
+		}
+	} else {
+		// Now we know that _no_ bits need to be erased to '1'.
+		
+		// Check if any bits are changed from '1' in the old value.
+		if( diff_mask ) {
+			// Now we know that _some_ bits need to the programmed to '0'.
+			
+			EEDR = new_value;   // Set EEPROM data register.
+			EECR = (1<<EEMPE) | // Set Master Write Enable bit...
+			       (1<<EEPM1);  // ...and Write-only mode.
+			EECR |= (1<<EEPE);  // Start Write-only operation.
+		}
+	}
+	
+	sei(); // Restore interrupt flag state.
+}
+
+void memcpy_to_eeprom_with_checksum(unsigned int destination, char *source, unsigned int size) {
+  unsigned char checksum = 0;
+  for(; size > 0; size--) { 
+    checksum = (checksum << 1) || (checksum >> 7);
+    checksum += *source;
+    eeprom_put_char(destination++, *(source++)); 
+  }
+  eeprom_put_char(destination, checksum);
+}
+
+int memcpy_from_eeprom_with_checksum(char *destination, unsigned int source, unsigned int size) {
+  unsigned char data, checksum = 0;
+  for(; size > 0; size--) { 
+    data = eeprom_get_char(source++);
+    checksum = (checksum << 1) || (checksum >> 7);
+    checksum += data;    
+    *(destination++) = data; 
+  }
+  return(checksum == eeprom_get_char(source));
+}
+
+// end of file

eeprom.h

@@ -0,0 +1,9 @@
+#ifndef eeprom_h
+#define eeprom_h
+
+char eeprom_get_char(unsigned int addr);
+void eeprom_put_char(unsigned int addr, char new_value);
+void memcpy_to_eeprom_with_checksum(unsigned int destination, char *source, unsigned int size);
+int memcpy_from_eeprom_with_checksum(char *destination, unsigned int source, unsigned int size);
+
+#endif

gcode.c

@@ -83,7 +83,7 @@ struct ParserState {
   uint8_t absolute_mode;       /* 0 = relative motion, 1 = absolute motion {G90, G91} */
   uint8_t program_flow;
   int spindle_direction;
-  double feed_rate;              /* Millimeters/second */
+  double feed_rate, seek_rate;              /* Millimeters/second */
   double position[3];    /* Where the interpreter considers the tool to be at this point in the code */
   uint8_t tool;
   int16_t spindle_speed;         /* RPM/100 */
@@ -110,7 +110,8 @@ void select_plane(uint8_t axis_0, uint8_t axis_1, uint8_t axis_2)
 
 void gc_init() {
   memset(&gc, 0, sizeof(gc));
-  gc.feed_rate = DEFAULT_FEEDRATE/60;
+  gc.feed_rate = settings.default_feed_rate/60;
+  gc.seek_rate = settings.default_seek_rate/60;
   select_plane(X_AXIS, Y_AXIS, Z_AXIS);
   gc.absolute_mode = TRUE;
 }
@@ -163,6 +164,16 @@ uint8_t gc_execute_line(char *line) {
   
   if (line[0] == '(') { return(gc.status_code); }
   if (line[0] == '/') { counter++; } // ignore block delete
+  if (line[0] == '$') { // This is a parameter line intended to change EEPROM-settings
+    // Parameter lines are on the form '$4=374.3' or '$' to dump current settings
+    counter = 1;
+    if(line[counter] == 0) { dump_settings(); return(GCSTATUS_OK); }
+    read_double(line, &counter, &p);
+    if(line[counter++] != '=') { return(GCSTATUS_UNSUPPORTED_STATEMENT); }
+    read_double(line, &counter, &value);
+    if(line[counter] != 0) { return(GCSTATUS_UNSUPPORTED_STATEMENT); }
+    store_setting(p, value);
+  }
   
   // Pass 1: Commands
   while(next_statement(&letter, &value, line, &counter)) {
@@ -256,7 +267,8 @@ uint8_t gc_execute_line(char *line) {
     case NEXT_ACTION_DEFAULT: 
     switch (gc.motion_mode) {
       case MOTION_MODE_CANCEL: break;
-      case MOTION_MODE_RAPID_LINEAR: case MOTION_MODE_LINEAR:
+      case MOTION_MODE_RAPID_LINEAR:
+      case MOTION_MODE_LINEAR:
       mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], 
         (gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode);
       break;

main.c

@@ -33,12 +33,12 @@
 int main(void)
 {
   beginSerial(BAUD_RATE);
+  config_init();
   st_init(); // initialize the stepper subsystem
   mc_init(); // initialize motion control subsystem
   spindle_init(); // initialize spindle controller
   gc_init(); // initialize gcode-parser
   sp_init(); // initialize the serial protocol
-//  sd_raw_init());
   
   DDRD |= (1<<3)|(1<<4)|(1<<5);
   

motion_control.c

@@ -51,9 +51,9 @@ void mc_line(double x, double y, double z, float feed_rate, int invert_feed_rate
   int32_t target[3]; // The target position in absolute steps
   int32_t steps[3]; // The target line in relative steps
   
-  target[X_AXIS] = lround(x*X_STEPS_PER_MM);
+  target[X_AXIS] = lround(x*settings.steps_per_mm[0]);
-  target[Y_AXIS] = lround(y*Y_STEPS_PER_MM);
+  target[Y_AXIS] = lround(y*settings.steps_per_mm[1]);
-  target[Z_AXIS] = lround(z*Z_STEPS_PER_MM); 
+  target[Z_AXIS] = lround(z*settings.steps_per_mm[2]); 
 
   for(axis = X_AXIS; axis <= Z_AXIS; axis++) {
     steps[axis] = target[axis]-position[axis];
@@ -64,9 +64,9 @@ void mc_line(double x, double y, double z, float feed_rate, int invert_feed_rate
 	} else {
   	// Ask old Phytagoras to estimate how many mm our next move is going to take us
   	double millimeters_of_travel = sqrt(
-  	  square(steps[X_AXIS]/X_STEPS_PER_MM) + 
+  	  square(steps[X_AXIS]/settings.steps_per_mm[0]) + 
-  	  square(steps[Y_AXIS]/Y_STEPS_PER_MM) + 
+  	  square(steps[Y_AXIS]/settings.steps_per_mm[1]) + 
-  	  square(steps[Z_AXIS]/Z_STEPS_PER_MM));
+  	  square(steps[Z_AXIS]/settings.steps_per_mm[2]));
     st_buffer_line(steps[X_AXIS], steps[Y_AXIS], steps[Z_AXIS],
       lround((millimeters_of_travel/feed_rate)*1000000));
 	}
@@ -80,14 +80,12 @@ void mc_line(double x, double y, double z, float feed_rate, int invert_feed_rate
 
 // The arc is approximated by generating a huge number of tiny, linear segments. The length of each 
 // segment is configured in config.h by setting MM_PER_ARC_SEGMENT.  
-
-// ISSUE: The arc interpolator assumes all axes have the same steps/mm as the X axis.
 void mc_arc(double theta, double angular_travel, double radius, double linear_travel, int axis_1, int axis_2, 
   int axis_linear, double feed_rate, int invert_feed_rate)
 {
   double millimeters_of_travel = hypot(angular_travel*radius, labs(linear_travel));
   if (millimeters_of_travel == 0.0) { return; }
-  uint16_t segments = ceil(millimeters_of_travel/MM_PER_ARC_SEGMENT);
+  uint16_t segments = ceil(millimeters_of_travel/settings.mm_per_arc_segment);
   // Multiply inverse feed_rate to compensate for the fact that this movement is approximated
   // by a number of discrete segments. The inverse feed_rate should be correct for the sum of 
   // all segments.
@@ -97,8 +95,8 @@ void mc_arc(double theta, double angular_travel, double radius, double linear_tr
   // The linear motion for each segment
   double linear_per_segment = linear_travel/segments;
   // Compute the center of this circle
-  double center_x = (position[axis_1]/X_STEPS_PER_MM)-sin(theta)*radius;
+  double center_x = (position[axis_1]/settings.steps_per_mm[axis_1])-sin(theta)*radius;
-  double center_y = (position[axis_2]/Y_STEPS_PER_MM)-cos(theta)*radius;
+  double center_y = (position[axis_2]/settings.steps_per_mm[axis_2])-cos(theta)*radius;
   // a vector to track the end point of each segment
   double target[3];
   int i;

readme.txt

@@ -1,4 +1,4 @@
-Grbl - An embedded rs274/ngc (g-code) integrater interpreter and motion-controller for the Arduino/AVR328 microcontroller
+Grbl - An embedded rs274/ngc (g-code) interpreter and motion-controller for the Arduino/AVR328 microcontroller
 
 Goal: A no-compromise, high performance, low cost alternative to parallel-port based motion control for CNC milling
 
@@ -10,12 +10,12 @@ Status:
 * Standards-compliant g-code arcs/circles fully supported
 * Buffered, non blocking, asynchronous step generation so the rest of the system is free to process
   g-code while the steppers are steppin'
+* Configuration parameters stored in EEPROM and set via simple commands
 * Tested on very few (two) CNC rigs
 
 Pending: 
 * Battle hardening in the field
 * Documentation and web-site
-* Simpler configuration (w/o recompilation)
 * Optional support for a alphanumeric LCD readout, a joystick and a few buttons for program control
 * Support "headless" fabrication by buffering all code to SD-card or similar
 * Easing of feed rate

stepper.c

@@ -95,8 +95,8 @@ SIGNAL(SIG_OUTPUT_COMPARE1A)
   // 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
-  // exactly STEP_PULSE_MICROSECONDS microseconds.
+  // exactly settings.pulse_microseconds microseconds.
-  TCNT2 = -(((STEP_PULSE_MICROSECONDS-2)*TICKS_PER_MICROSECOND)/8);
+  TCNT2 = -(((settings.pulse_microseconds-2)*TICKS_PER_MICROSECOND)/8);
 
   busy = TRUE;
   sei(); // Re enable interrupts (normally disabled while inside an interrupt handler)
@@ -150,17 +150,17 @@ SIGNAL(SIG_OUTPUT_COMPARE1A)
   } else {
     out_bits = 0;
   }
-  out_bits ^= STEPPING_INVERT_MASK;
+  out_bits ^= settings.invert_mask;
   busy=FALSE;
   PORTD &= ~(1<<3);  
 }
 
 // This interrupt is set up by SIG_OUTPUT_COMPARE1A when it sets the motor port bits. It resets
-// the motor port after a short period (STEP_PULSE_MICROSECONDS) completing one step cycle.
+// the motor port after a short period (settings.pulse_microseconds) completing one step cycle.
 SIGNAL(SIG_OVERFLOW2)
 {
   // reset stepping pins (leave the direction pins)
-  STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | (STEPPING_INVERT_MASK & STEP_MASK); 
+  STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | (settings.invert_mask & STEP_MASK); 
 }
 
 // Initialize and start the stepper motor subsystem
@@ -168,7 +168,7 @@ void st_init()
 {
 	// Configure directions of interface pins
   STEPPING_DDR   |= STEPPING_MASK;
-  STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK); //| STEPPING_INVERT_MASK;
+  STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK) | settings.invert_mask;
   LIMIT_DDR &= ~(LIMIT_MASK);
   STEPPERS_ENABLE_DDR |= 1<<STEPPERS_ENABLE_BIT;
   

todo.txt

@@ -1,4 +1,4 @@
-* Use errno to detect fp-errors
+* Complete support for using and setting separate seek-rate for G0-commnads
 * Implement homing cycle in stepper.c
 * Implement limit switch support in stepper.c (use port-triggered interrupts?)
 * Tool change M6

wiring_serial.c

@@ -180,6 +180,15 @@ void printInteger(long n)
 	printIntegerInBase(n, 10);
 }
 
+void printFloat(double n)
+{
+  double integer_part, fractional_part;
+  fractional_part = modf(n, &integer_part);
+  printInteger(integer_part);
+  printByte('.');
+  printInteger(round(fractional_part*1000));
+}
+
 // void printHex(unsigned long n)
 // {
 //  printIntegerInBase(n, 16);

wiring_serial.h

@@ -39,5 +39,6 @@ void printHex(unsigned long n);
 void printOctal(unsigned long n);
 void printBinary(unsigned long n);
 void printIntegerInBase(unsigned long n, unsigned long base);
+void printFloat(double n);
 
 #endif