Merge chamnit/v0_7 with grbl/master

stepper.h

@@ -24,6 +24,11 @@
 #include <avr/io.h>
 #include <avr/sleep.h>
 
+#define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
+#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)
+
 // Initialize and start the stepper motor subsystem
 void st_init();
 
@@ -33,8 +38,7 @@ void st_synchronize();
 // Execute the homing cycle
 void st_go_home();
              
-// The stepper subsystem goes to sleep when it runs out of things to execute. Call this
-// to notify the subsystem that it is time to go to work.
-void st_wake_up();
+// Notify the stepper subsystem to start executing the g-code program in buffer.
+void st_cycle_start();
 
 #endif