From 58ad1ba50933ef048b62552504408bed54f81eb0 Mon Sep 17 00:00:00 2001
From: Simen Svale Skogsrud <simen@simens-2.local>
Date: Thu, 4 Mar 2010 21:18:55 +0100
Subject: [PATCH] minor edits after verifying refactored grbl on real hardware

---
 Makefile                |  2 +-
 config.h                | 11 ++++++-----
 gcode/braid_cut2d.gcode |  2 +-
 main.c                  |  1 +
 motion_control.c        |  1 -
 script/stream           |  2 +-
 stepper.c               | 31 ++++++++++++++-----------------
 7 files changed, 24 insertions(+), 26 deletions(-)

diff --git a/Makefile b/Makefile
index b2eab6a..36073c0 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,7 @@
 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
 
 # Tune the lines below only if you know what you are doing:
diff --git a/config.h b/config.h
index c34171f..f772f37 100644
--- a/config.h
+++ b/config.h
@@ -23,9 +23,10 @@
 
 #define VERSION "0.5"
 
-#define X_STEPS_PER_MM (94.488188976378*16)
-#define Y_STEPS_PER_MM (94.488188976378*16)
-#define Z_STEPS_PER_MM (94.488188976378*16)
+#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
 
@@ -74,12 +75,12 @@
 #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
+#define STEPPING_INVERT_MASK 0
 // Uncomment this line for inverted stepping (step-pulses low, rest high)
 // #define STEPPING_INVERT_MASK (STEP_MASK)
 // Uncomment this line to invert all step- and direction bits
 // #define STEPPING_INVERT_MASK (STEPPING_MASK)
 // Or bake your own like this adding any step-bits or directions you want to invert:
-// #define STEPPING_INVERT_MASK (STEP_MASK | (1<<Z_DIRECTION_BIT))
+// #define STEPPING_INVERT_MASK (STEP_MASK | (1<<X_DIRECTION_BIT) | (1<<Y_DIRECTION_BIT))
 
 #endif
diff --git a/gcode/braid_cut2d.gcode b/gcode/braid_cut2d.gcode
index 3d78460..9b0c3c5 100644
--- a/gcode/braid_cut2d.gcode
+++ b/gcode/braid_cut2d.gcode
@@ -5,7 +5,7 @@ G0X0.000Y0.000S8000M3
 G0X0.000Y-33.519Z6.000
 G1Z-1.000
 G1X0.327Y-33.521
-F120.0
+F800.0
 X0.654Y-33.526
 X0.980Y-33.534
 X1.304Y-33.546
diff --git a/main.c b/main.c
index b01d6a5..518fa1b 100644
--- a/main.c
+++ b/main.c
@@ -38,6 +38,7 @@ int main(void)
   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);
   
diff --git a/motion_control.c b/motion_control.c
index 403fda2..3cdfad5 100644
--- a/motion_control.c
+++ b/motion_control.c
@@ -73,7 +73,6 @@ void mc_line(double x, double y, double z, float feed_rate, int invert_feed_rate
 	memcpy(position, target, sizeof(target)); // position[] = target[] 
 }
 
-
 // Execute an arc. theta == start angle, angular_travel == number of radians to go along the arc,
 // positive angular_travel means clockwise, negative means counterclockwise. Radius == the radius of the
 // circle in millimeters. axis_1 and axis_2 selects the circle plane in tool space. Stick the remaining
diff --git a/script/stream b/script/stream
index fcd4c6b..89dc0d7 100755
--- a/script/stream
+++ b/script/stream
@@ -1,2 +1,2 @@
 #!/opt/local/bin/ruby
-require 'stream'
\ No newline at end of file
+require 'script/stream'
\ No newline at end of file
diff --git a/stepper.c b/stepper.c
index 110a4a3..47242b3 100644
--- a/stepper.c
+++ b/stepper.c
@@ -46,11 +46,11 @@ volatile int line_buffer_head = 0;
 volatile int line_buffer_tail = 0;
 
 // Variables used by SIG_OUTPUT_COMPARE1A
-uint8_t out_bits;
-struct Line *current_line;
-volatile int32_t counter_x, counter_y, counter_z;
-uint32_t iterations;
-volatile busy;
+uint8_t out_bits; // The next stepping-bits to be output
+struct Line *current_line; // A pointer to the line currently being traced
+volatile 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_line
+volatile busy; // TRUE when SIG_OUTPUT_COMPARE1A is being serviced. Used to avoid retriggering that handler.
 
 void config_step_timer(uint32_t microseconds);
 
@@ -62,8 +62,7 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
 	// If the buffer is full: good! That means we are well ahead of the robot. 
 	// Nap until there is room in the buffer.
   while(line_buffer_tail == next_buffer_head) { sleep_mode(); }
-  
-  // setup line
+  // Setup line record
   struct Line *line = &line_buffer[line_buffer_head];
   line->steps_x = labs(steps_x);
   line->steps_y = labs(steps_y);
@@ -83,28 +82,26 @@ void st_buffer_line(int32_t steps_x, int32_t steps_y, int32_t steps_z, uint32_t
 	TIMSK1 |= (1<<OCIE1A);
 }
 
-// This timer interrupt is executed at the pace set with st_buffer_pace. It pops one instruction from
+// 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.
 SIGNAL(SIG_OUTPUT_COMPARE1A)
 {
-  if(busy){ return; } // The busy-flag is used to avoid retriggering this interrupt.
+  if(busy){ return; } // The busy-flag is used to avoid reentering this interrupt
   
   PORTD |= (1<<3);
   // Set the direction pins a cuple of nanoseconds before we step the steppers
   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
+  // Reset step pulse reset timer so that SIG_OVERFLOW2 can reset the signal after
+  // exactly STEP_PULSE_MICROSECONDS microseconds.
   TCNT2 = -(((STEP_PULSE_MICROSECONDS-2)*TICKS_PER_MICROSECOND)/8);
 
   busy = TRUE;
-  sei();
+  sei(); // Re enable interrupts (normally disabled while inside an interrupt handler)
   // We re-enable interrupts in order for SIG_OVERFLOW2 to be able to be triggered 
-  // and reset the stepper signal even before this handler is done. Needed
-  // to generate a clean stepper-signal in the event that this is going to be a time consuming
-  // time around in this interrupt e.g. if we just completed a line and need to
-  // set up another. 
+  // at exactly the right time even if we occasionally spend a lot of time inside this handler.
     
   // If there is no current line, attempt to pop one from the buffer
   if (current_line == NULL) {
@@ -115,7 +112,7 @@ SIGNAL(SIG_OUTPUT_COMPARE1A)
       // Retrieve a new line and get ready to step it
       current_line = &line_buffer[line_buffer_tail]; 
       config_step_timer(current_line->rate);
-      counter_x = -(current_line->maximum_steps/2);
+      counter_x = -(current_line->maximum_steps >> 1);
       counter_y = counter_x;
       counter_z = counter_x;
       iterations = current_line->maximum_steps;
@@ -213,7 +210,7 @@ void st_flush()
   sei();
 }
 
-// Configures the prescaler and ceiling of timer 1 to produce the given pace as accurately as possible.
+// Configures the prescaler and ceiling of timer 1 to produce the given rate as accurately as possible.
 void config_step_timer(uint32_t microseconds)
 {
   uint32_t ticks = microseconds*TICKS_PER_MICROSECOND;