Fixed a very rare but critical bug when reducing override rates.

- See main branch commit log for details.

Author: chamnit

doc/log/commit_log_v1.0d.txt

@@ -1,3 +1,13 @@
+----------------
+Date: 2017-08-01
+Author: Sonny Jeon
+Subject: Fixed RAMPS control pin conflict
+
+[fix] RAMPS soft-reset control pin interfered with Z-enable. Shifted
+all control pins by plus one on the analog pins. RAMPS defines these
+pins as belonging to the AUX 2 port, which is assumed to be unused.
+
+
 ----------------
 Date: 2017-07-17
 Author: Sonny Jeon

grbl/grbl.h

@@ -23,7 +23,7 @@
 
 // Grbl versioning system
 #define GRBL_VERSION "1.1f"
-#define GRBL_VERSION_BUILD "20170801"
+#define GRBL_VERSION_BUILD "20170802"
 
 // Define standard libraries used by Grbl.
 #include <avr/io.h>

grbl/stepper.c

@@ -973,15 +973,14 @@ void st_prep_buffer()
       switch (prep.ramp_type) {
         case RAMP_DECEL_OVERRIDE:
           speed_var = pl_block->acceleration*time_var;
-          mm_var = time_var*(prep.current_speed - 0.5*speed_var);
-          mm_remaining -= mm_var;
-          if ((mm_remaining < prep.accelerate_until) || (mm_var <= 0)) {
+          if (prep.current_speed-prep.maximum_speed <= speed_var) {
             // Cruise or cruise-deceleration types only for deceleration override.
-            mm_remaining = prep.accelerate_until; // NOTE: 0.0 at EOB
+            mm_remaining = prep.accelerate_until;
             time_var = 2.0*(pl_block->millimeters-mm_remaining)/(prep.current_speed+prep.maximum_speed);
             prep.ramp_type = RAMP_CRUISE;
             prep.current_speed = prep.maximum_speed;
           } else { // Mid-deceleration override ramp.
+            mm_remaining -= time_var*(prep.current_speed - 0.5*speed_var);
             prep.current_speed -= speed_var;
           }
           break;