tweaks and bugfixes

Makefile

@@ -39,7 +39,7 @@ AVRDUDE = avrdude $(PROGRAMMER) -p $(DEVICE) -B 10
 COMPILE = avr-gcc -Wall -Os -DF_CPU=$(CLOCK) -mmcu=$(DEVICE) -I. 
 
 # symbolic targets:
-all:	main.hex
+all:	grbl.hex
 
 .c.o:
 	$(COMPILE) -c $< -o $@ 
@@ -55,7 +55,7 @@ all:	main.hex
 	$(COMPILE) -S $< -o $@
 
 flash:	all
-	$(AVRDUDE) -U flash:w:main.hex:i
+	$(AVRDUDE) -U flash:w:grbl.hex:i
 
 fuse:
 	$(AVRDUDE) $(FUSES)
@@ -65,19 +65,19 @@ install: flash fuse
 
 # if you use a bootloader, change the command below appropriately:
 load: all
-	bootloadHID main.hex
+	bootloadHID grbl.hex
 
 clean:
-	rm -f main.hex main.elf $(OBJECTS)
+	rm -f grbl.hex main.elf $(OBJECTS)
 
 # file targets:
 main.elf: $(OBJECTS)
 	$(COMPILE) -o main.elf $(OBJECTS) -lm
 
-main.hex: main.elf
-	rm -f main.hex
-	avr-objcopy -j .text -j .data -O ihex main.elf main.hex
-	avr-size main.hex *.o
+grbl.hex: main.elf
+	rm -f grbl.hex
+	avr-objcopy -j .text -j .data -O ihex main.elf grbl.hex
+	avr-size grbl.hex *.o
 # If you have an EEPROM section, you must also create a hex file for the
 # EEPROM and add it to the "flash" target.
 

gcode.c

@@ -30,12 +30,12 @@
   - Variables
   - Multiple home locations
   - Probing
-  - Spindle direction  
   - Override control
 */
 
 /* 
    Omitted for the time being:
+ - Spindle direction  
    
    group 0 = {G10, G28, G30, G53, G92, G92.1, G92.2, G92.3} (Non modal G-codes)
    group 5 = {G93, G94} feed rate mode
@@ -126,7 +126,7 @@ uint8_t gc_execute_line(char *line) {
   double unit_converted_value;
   double inverse_feed_rate;
   
-  uint8_t absolute_mode = 0;       /* 0 = relative motion, 1 = absolute motion {G90, G91} */
+  uint8_t absolute_mode;       /* 0 = relative motion, 1 = absolute motion {G90, G91} */
   uint8_t next_action = NEXT_ACTION_DEFAULT;         /* One of the NEXT_ACTION_-constants */
   
   double target[3], offset[3];

motion_control.c

@@ -18,7 +18,13 @@
   along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-/* This code was inspired by the Arduino GCode_Interpreter by Mike Ellery. */
+/* The structure of this module was inspired by the Arduino GCode_Interpreter by Mike Ellery. The arc
+   interpolator written from the information provided in the Wikipedia article 'Midpoint circle algorithm'
+   and the lecture 'Circle Drawing Algorithms' by Leonard McMillan. 
+   
+   http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
+   http://www.cs.unc.edu/~mcmillan/comp136/Lecture7/circle.html
+*/
 
 #include <avr/io.h>
 #include "config.h"

readme.txt

@@ -2,7 +2,9 @@ Grbl - An embedded rs274/ngc (g-code) interpreter, CNC controller, readout and e
 Inspired by the Arduino GCode Interpreter by Mike Ellery
 
 Status:
-* Linear interpolation machine control complete (No arcs yet)
+* Linear interpolation machine control complete (Arc support in embryonic state)
+* Buffered, non blocking, asynchronous stepping so the rest of the system is free to generate new steps and parse 
+  g-code while the steppers are still steppin' 
 * GCode interpreter complete
 * Basic serial protocol complete
 * As of yet completely untested in a real environemnt. Still waiting for my micRo kit from Lumenlab.com

serial_protocol.c

@@ -40,15 +40,14 @@ void print_result() {
   int inches_mode;
   uint8_t status_code;
   uint32_t line_number;
+  int i; // loop variable
   gc_get_status(position, &status_code, &inches_mode, &line_number);
-  printByte('[');  
-  printInteger(trunc(position[X_AXIS]*100));
-  printByte(',');
-  printInteger(trunc(position[Y_AXIS]*100));
-  printByte(',');
-  printInteger(trunc(position[Z_AXIS]*100));
-  printByte(']');
+  printString("[ ");  
+  for(i=X_AXIS; i<=Z_AXIS; i++) {
+    printInteger(trunc(position[i]*100));
     printByte(' ');
+  }
+  printByte(']');
   printByte('@');
   printInteger(line_number);
   printByte(':');

stepper.c

@@ -18,6 +18,9 @@
   along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+/* The timer calculations of this module informed by the 'RepRap cartesian firmware' by Zack Smith
+   and Philipp Tiefenbacher. The circle buffer implementation by the wiring_serial library by David A. Mellis */
+
 #include "stepper.h"
 #include "config.h"
 #include "nuts_bolts.h"
@@ -30,7 +33,7 @@ volatile uint8_t step_buffer[STEP_BUFFER_SIZE]; // A buffer for step instruction
 volatile int step_buffer_head = 0;
 volatile int step_buffer_tail = 0;
 
-uint8_t state = STEPPER_STATE_STOPPED;
+uint8_t stepper_mode = STEPPER_MODE_STOPPED;
 
 // This timer interrupt is executed at the pace set with set_pace. It pops one instruction from
 // the step_buffer, executes it. Then it starts timer2 in order to reset the motor port after
@@ -77,7 +80,7 @@ void st_init()
 	
 	// Configure Timer 2
   TCCR2A = 0; // Normal operation
-  TCCT2B = 1<<CS20; // Full speed, no prescaler
+  TCCR2B = 1<<CS20; // Full speed, no prescaler
   TIMSK2 = 0; // All interrupts disabled
   
 	// start off with a slow pace
@@ -100,7 +103,7 @@ void st_buffer_step(uint8_t motor_port_bits)
 // Block until all buffered steps are executed
 void st_synchronize()
 {
-  if (state == STEPPER_MODE_RUNNING) {
+  if (stepper_mode == STEPPER_MODE_RUNNING) {
     while(step_buffer_tail != step_buffer_head) { sleep_mode(); }    
   } else {
     st_flush();
@@ -119,7 +122,7 @@ void st_start()
   // Enable timer interrupt
 	TIMSK1 |= (1<<OCIE1A);
   STEPPERS_ENABLE_PORT |= 1<<STEPPERS_ENABLE_BIT;
-  state = STEPPER_STATE_RUNNING;
+  stepper_mode = STEPPER_MODE_RUNNING;
 }
 
 // Execute all buffered steps, then stop the stepper subsystem
@@ -128,7 +131,7 @@ inline void st_stop()
   st_synchronize();
 	TIMSK1 &= ~(1<<OCIE1A);
   STEPPERS_ENABLE_PORT &= ~(1<<STEPPERS_ENABLE_BIT);
-  state = STEPPER_STATE_STOPPED;
+  stepper_mode = STEPPER_MODE_STOPPED;
 }
 
 void st_set_pace(uint32_t microseconds)
@@ -181,25 +184,25 @@ int check_limit_switch(int axis)
 // void perform_go_home() 
 // {
 //   int axis;
-//   if(state.home.phase == PHASE_HOME_RETURN) {
+//   if(stepper_mode.home.phase == PHASE_HOME_RETURN) {
 //     // We are running all axes in reverse until all limit switches are tripped
 //     // Check all limit switches:
 //     for(axis=X_AXIS; axis <= Z_AXIS; axis++) {
-//       state.home.away[axis] |= check_limit_switch(axis);
+//       stepper_mode.home.away[axis] |= check_limit_switch(axis);
 //     }
 //     // Step steppers. First retract along Z-axis. Then X and Y.
-//     if(state.home.away[Z_AXIS]) {
+//     if(stepper_mode.home.away[Z_AXIS]) {
 //       step_axis(Z_AXIS);
 //     } else {
 //       // Check if all axes are home
-//       if(!(state.home.away[X_AXIS] || state.home.away[Y_AXIS])) {
+//       if(!(stepper_mode.home.away[X_AXIS] || stepper_mode.home.away[Y_AXIS])) {
 //         // All axes are home, prepare next phase: to nudge the tool carefully out of the limit switches
-//         memset(state.home.direction, 1, sizeof(state.home.direction)); // direction = [1,1,1]
-//         set_direction_bits(state.home.direction);
-//         state.home.phase == PHASE_HOME_NUDGE;
+//         memset(stepper_mode.home.direction, 1, sizeof(stepper_mode.home.direction)); // direction = [1,1,1]
+//         set_direction_bits(stepper_mode.home.direction);
+//         stepper_mode.home.phase == PHASE_HOME_NUDGE;
 //         return;
 //       }
-//       step_steppers(state.home.away);
+//       step_steppers(stepper_mode.home.away);
 //     }
 //   } else {    
 //     for(axis=X_AXIS; axis <= Z_AXIS; axis++) {
@@ -209,8 +212,8 @@ int check_limit_switch(int axis)
 //       }
 //     }
 //     // When this code is reached it means all axes are free of their limit-switches. Complete the cycle and rest:
-//     clear_vector(state.position); // By definition this is location [0, 0, 0]
-//     state.mode = MODE_AT_REST;
+//     clear_vector(stepper_mode.position); // By definition this is location [0, 0, 0]
+//     stepper_mode.mode = MODE_AT_REST;
 //   }
 // }
 

stepper.h

@@ -24,10 +24,10 @@
 #include <avr/io.h>
 #include <avr/sleep.h>
 
-#define STEPPER_STATE_STOPPED 0
-#define STEPPER_STATE_RUNNING 1
-#define STEPPER_STATE_LIMIT_OVERRUN 2
-#define STEPPER_STATE_HOMING 3
+#define STEPPER_MODE_STOPPED 0
+#define STEPPER_MODE_RUNNING 1
+#define STEPPER_MODE_LIMIT_OVERRUN 2
+#define STEPPER_MODE_HOMING 3
 
 // Initialize and start the stepper motor subsystem
 void st_init();

todo.txt

@@ -1,3 +1,6 @@
+* Implement homing cycle in stepper.c
+* Implement limit switch support in stepper.c (use port-triggered interrupts?)
+* How to implement st_set_pace? Consider synchronizing when pace is changed
 * Eliminate need for circle_x and circle_y in step_arc_along…
 * Use timer interrupts to drive steppers
 * Tool table

wiring_serial.c

@@ -128,21 +128,21 @@ SIGNAL(SIG_UART_RECV)
 	}
 }
 
-void printMode(int mode)
-{
-	// do nothing, we only support serial printing, not lcd.
-}
+// void printMode(int mode)
+// {
+//  // do nothing, we only support serial printing, not lcd.
+// }
 
 void printByte(unsigned char c)
 {
 	serialWrite(c);
 }
 
-void printNewline()
-{
-	printByte('\n');
-}
-
+// void printNewline()
+// {
+//  printByte('\n');
+// }
+// 
 void printString(const char *s)
 {
 	while (*s)
@@ -180,20 +180,20 @@ void printInteger(long n)
 	printIntegerInBase(n, 10);
 }
 
-void printHex(unsigned long n)
-{
-	printIntegerInBase(n, 16);
-}
-
-void printOctal(unsigned long n)
-{
-	printIntegerInBase(n, 8);
-}
-
-void printBinary(unsigned long n)
-{
-	printIntegerInBase(n, 2);
-}
+// void printHex(unsigned long n)
+// {
+//  printIntegerInBase(n, 16);
+// }
+// 
+// void printOctal(unsigned long n)
+// {
+//  printIntegerInBase(n, 8);
+// }
+// 
+// void printBinary(unsigned long n)
+// {
+//  printIntegerInBase(n, 2);
+// }
 
 /* Including print() adds approximately 1500 bytes to the binary size,
  * so we replace it with the smaller and less-confusing printString(),