Minor prescalar optimization. Changed up some defines.

config.h

@@ -58,14 +58,13 @@
 #define COOLANT_FLOOD_PORT   PORTC
 #define COOLANT_FLOOD_BIT  0  // Uno Analog Pin 0
 
-#define ENABLE_M7 0 // DISABLED BY DEFAULT: To enable, change to '1' and recompile.
+//   #define ENABLE_M7  // Mist coolant disabled by default. Uncomment to enable.
-#if ENABLE_M7
+#ifdef ENABLE_M7
   #define COOLANT_MIST_DDR   DDRC
   #define COOLANT_MIST_PORT   PORTC
   #define COOLANT_MIST_BIT  1 // Uno Analog Pin 1
 #endif  
 
-
 // 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
 // that do not and must not exist in the streamed g-code program. ASCII control characters may be 
@@ -87,7 +86,7 @@
 // entering g-code into grbl, i.e. locating part zero or simple manual machining. If the axes drift,
 // grbl has no way to know this has happened, since stepper motors are open-loop control. Depending
 // on the machine, this parameter may need to be larger or smaller than the default time.
-// NOTE: If set to zero, the delay will not be compiled.
+// NOTE: If the define commented, the delay will not be compiled.
 #define STEPPER_IDLE_LOCK_TIME 25 // (milliseconds) - Integer > 0
 
 // The temporal resolution of the acceleration management subsystem. Higher number give smoother
@@ -137,7 +136,7 @@
 // As well as, older FTDI FT232RL-based Arduinos(Duemilanove) are known to work with standard
 // terminal programs since their firmware correctly manage these XON/XOFF characters. In any
 // case, please report any successes to grbl administrators!
-#define ENABLE_XONXOFF 0 // Boolean. Default disabled.
+// #define ENABLE_XONXOFF // Default disabled. Uncomment to enable.
 
 // Creates a delay between the direction pin setting and corresponding step pulse by creating
 // another interrupt (Timer2 compare) to manage it. The main Grbl interrupt (Timer1 compare) 
@@ -151,9 +150,9 @@
 // of your successes or difficulties, as we will monitor this and possibly integrate this as a 
 // standard feature for future releases. However, we suggest to first try our direction delay
 // hack/solution posted in the Wiki involving inverting the stepper pin mask.
-// NOTE: If set greater than zero, step pulse delay will be compiled and enabled. Also, the 
+// NOTE: Uncomment to enable. The recommended delay should be > 3us but not exceed a total
-// total delay added with the Grbl settings pulse microseconds must not exceed 127 ms.
+// time of 127us when added with the Grbl settings pulse microsecond.
-#define STEP_PULSE_DELAY 0 // Step pulse delay in microseconds. Default disabled.
+// #define STEP_PULSE_DELAY 5 // Step pulse delay in microseconds. Default disabled.
 
 // ---------------------------------------------------------------------------------------
 

coolant_control.c

@@ -39,7 +39,7 @@ void coolant_init()
 
 void coolant_stop()
 {
-  #if ENABLE_M7
+  #ifdef ENABLE_M7
     COOLANT_MIST_PORT &= ~(1 << COOLANT_MIST_BIT);
   #endif
   COOLANT_FLOOD_PORT &= ~(1 << COOLANT_FLOOD_BIT);
@@ -53,7 +53,7 @@ void coolant_run(uint8_t mode)
     plan_synchronize(); // Ensure coolant turns on when specified in program.
     if (mode == COOLANT_FLOOD_ENABLE) { 
       COOLANT_FLOOD_PORT |= (1 << COOLANT_FLOOD_BIT);
-    #if ENABLE_M7  
+    #ifdef ENABLE_M7  
       } else if (mode == COOLANT_MIST_ENABLE) {
           COOLANT_MIST_PORT |= (1 << COOLANT_MIST_BIT);
     #endif

gcode.c

@@ -216,7 +216,7 @@ uint8_t gc_execute_line(char *line)
           case 3: gc.spindle_direction = 1; break;
           case 4: gc.spindle_direction = -1; break;
           case 5: gc.spindle_direction = 0; break;
-          #if ENABLE_M7
+          #ifdef ENABLE_M7
             case 7: gc.coolant_mode = COOLANT_MIST_ENABLE; break;
           #endif
           case 8: gc.coolant_mode = COOLANT_FLOOD_ENABLE; break;
@@ -578,16 +578,16 @@ static int next_statement(char *letter, double *double_ptr, char *line, uint8_t
   - Evaluation of expressions
   - Variables
   - Multiple home locations
-  - Multiple coordinate systems (Up to 6 may be added via config.h)
   - Probing
   - Override control
   - Tool changes
    
+   (*) Indicates optional parameter, enabled through config.h and re-compile
    group 0 = {G92.2, G92.3} (Non modal: Cancel and re-enable G92 offsets)
    group 1 = {G38.2, G81 - G89} (Motion modes: straight probe, canned cycles)
    group 6 = {M6} (Tool change)
-   group 8 = {M7} coolant (M7 mist may be enabled via config.h)
+   group 8 = {*M7} enable mist coolant
    group 9 = {M48, M49} enable/disable feed and speed override switches
-   group 12 = {G55, G56, G57, G58, G59, G59.1, G59.2, G59.3} coordinate system selection
+   group 12 = {*G55, *G56, *G57, *G58, *G59, G59.1, G59.2, G59.3} coordinate system selection
    group 13 = {G61, G61.1, G64} path control mode
 */

stepper.c

@@ -91,7 +91,7 @@ static void st_wake_up()
   // Initialize stepper output bits
   out_bits = (0) ^ (settings.invert_mask); 
   // Initialize step pulse timing from settings. Here to ensure updating after re-writing.
-  #if STEP_PULSE_DELAY > 0
+  #ifdef STEP_PULSE_DELAY
     // Set total step pulse time after direction pin set. Ad hoc computation from oscilloscope.
     step_pulse_time = -(((settings.pulse_microseconds+STEP_PULSE_DELAY-2)*TICKS_PER_MICROSECOND) >> 3);
     // Set delay between direction pin write and step command.
@@ -113,7 +113,7 @@ void st_go_idle()
   TIMSK1 &= ~(1<<OCIE1A); 
   // Force stepper dwell to lock axes for a defined amount of time to ensure the axes come to a complete
   // stop and not drift from residual inertial forces at the end of the last movement.
-  #if STEPPER_IDLE_LOCK_TIME > 0
+  #ifdef STEPPER_IDLE_LOCK_TIME
     _delay_ms(STEPPER_IDLE_LOCK_TIME);   
   #endif
   // Disable steppers by setting stepper disable
@@ -145,7 +145,7 @@ ISR(TIMER1_COMPA_vect)
   // Set the direction pins a couple of nanoseconds before we step the steppers
   STEPPING_PORT = (STEPPING_PORT & ~DIRECTION_MASK) | (out_bits & DIRECTION_MASK);
   // Then pulse the stepping pins
-  #if STEP_PULSE_DELAY > 0
+  #ifdef STEP_PULSE_DELAY
     step_bits = (STEPPING_PORT & ~STEP_MASK) | out_bits; // Store out_bits to prevent overwriting.
   #else  // Normal operation
     STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | out_bits;
@@ -314,7 +314,7 @@ ISR(TIMER2_OVF_vect)
   TCCR2B = 0; // Disable Timer2 to prevent re-entering this interrupt when it's not needed. 
 }
 
-#if STEP_PULSE_DELAY > 0
+#ifdef STEP_PULSE_DELAY
   // This interrupt is used only when STEP_PULSE_DELAY is enabled. Here, the step pulse is
   // initiated after the STEP_PULSE_DELAY time period has elapsed. The ISR TIMER2_OVF interrupt
   // will then trigger after the appropriate settings.pulse_microseconds, as in normal operation.
@@ -358,7 +358,7 @@ void st_init()
   TCCR2B = 0; // Disable timer until needed.
   TIMSK2 |= (1<<TOIE2);      
   
-  #if STEP_PULSE_DELAY > 0
+  #ifdef STEP_PULSE_DELAY
     TIMSK2 |= (1<<OCIE2A); // Enable Timer2 Compare Match A interrupt
   #endif
   
@@ -371,36 +371,36 @@ void st_init()
 static uint32_t config_step_timer(uint32_t cycles)
 {
   uint16_t ceiling;
-  uint16_t prescaler;
+  uint8_t prescaler;
   uint32_t actual_cycles;
   if (cycles <= 0xffffL) {
     ceiling = cycles;
-    prescaler = 0; // prescaler: 0
+    prescaler = 1; // prescaler: 0
     actual_cycles = ceiling;
   } else if (cycles <= 0x7ffffL) {
     ceiling = cycles >> 3;
-    prescaler = 1; // prescaler: 8
+    prescaler = 2; // prescaler: 8
     actual_cycles = ceiling * 8L;
   } else if (cycles <= 0x3fffffL) {
     ceiling =  cycles >> 6;
-    prescaler = 2; // prescaler: 64
+    prescaler = 3; // prescaler: 64
     actual_cycles = ceiling * 64L;
   } else if (cycles <= 0xffffffL) {
     ceiling =  (cycles >> 8);
-    prescaler = 3; // prescaler: 256
+    prescaler = 4; // prescaler: 256
     actual_cycles = ceiling * 256L;
   } else if (cycles <= 0x3ffffffL) {
     ceiling = (cycles >> 10);
-    prescaler = 4; // prescaler: 1024
+    prescaler = 5; // prescaler: 1024
     actual_cycles = ceiling * 1024L;    
   } else {
     // Okay, that was slower than we actually go. Just set the slowest speed
     ceiling = 0xffff;
-    prescaler = 4;
+    prescaler = 6;
     actual_cycles = 0xffff * 1024;
   }
   // Set prescaler
-  TCCR1B = (TCCR1B & ~(0x07<<CS10)) | ((prescaler+1)<<CS10);
+  TCCR1B = (TCCR1B & ~(0x07<<CS10)) | (prescaler<<CS10);
   // Set ceiling
   OCR1A = ceiling;
   return(actual_cycles);