From 59a4d2ef06bc5ce09f6d38735f4638b1a63642e7 Mon Sep 17 00:00:00 2001
From: chamnit <chamnit@Masamune.local>
Date: Mon, 25 Jul 2016 13:50:08 -0600
Subject: [PATCH] CoreXY homing bug fix attempt 2.

---
 grbl/config.h  | 4 ++--
 grbl/limits.c  | 7 +++----
 grbl/planner.c | 4 ++--
 grbl/system.c  | 3 +--
 grbl/system.h  | 1 +
 5 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/grbl/config.h b/grbl/config.h
index d524796..f01935b 100644
--- a/grbl/config.h
+++ b/grbl/config.h
@@ -72,8 +72,8 @@
 // on separate pin, but homed in one cycle. Also, it should be noted that the function of hard limits 
 // will not be affected by pin sharing.
 // NOTE: Defaults are set for a traditional 3-axis CNC machine. Z-axis first to clear, followed by X & Y.
-#define HOMING_CYCLE_0 (1<<Z_AXIS)                // REQUIRED: First move Z to clear workspace.
-#define HOMING_CYCLE_1 ((1<<X_AXIS)|(1<<Y_AXIS))  // OPTIONAL: Then move X,Y at the same time.
+#define HOMING_CYCLE_0 (1<<X_AXIS)                // REQUIRED: First move Z to clear workspace.
+#define HOMING_CYCLE_1 (1<<Y_AXIS)  // OPTIONAL: Then move X,Y at the same time.
 // #define HOMING_CYCLE_2                         // OPTIONAL: Uncomment and add axes mask to enable
 
 // Number of homing cycles performed after when the machine initially jogs to limit switches.
diff --git a/grbl/limits.c b/grbl/limits.c
index 947a6ed..47e70bf 100644
--- a/grbl/limits.c
+++ b/grbl/limits.c
@@ -185,13 +185,12 @@ void limits_go_home(uint8_t cycle_mask)
       if (bit_istrue(cycle_mask,bit(idx))) {
         n_active_axis++;
         #ifdef COREXY
-          int32_t axis_position;
           if (idx == X_AXIS) {
-            axis_position = system_convert_corexy_to_x_axis_steps(sys.position);
+            int32_t axis_position = system_convert_corexy_to_y_axis_steps(sys.position);
             sys.position[A_MOTOR] = axis_position;
             sys.position[B_MOTOR] = -axis_position;
           } else if (idx == Y_AXIS) {
-            axis_position = system_convert_corexy_to_y_axis_steps(sys.position);
+            int32_t axis_position = system_convert_corexy_to_x_axis_steps(sys.position);
             sys.position[A_MOTOR] = sys.position[B_MOTOR] = axis_position;
           } else { 
             sys.position[Z_AXIS] = 0; 
@@ -306,7 +305,7 @@ void limits_go_home(uint8_t cycle_mask)
         }
       #endif
       
-      #ifdef COREXY
+      #ifdef COREXY    
         if (idx==X_AXIS) { 
           int32_t off_axis_position = system_convert_corexy_to_y_axis_steps(sys.position);
           sys.position[A_MOTOR] = set_axis_position + off_axis_position;
diff --git a/grbl/planner.c b/grbl/planner.c
index f1eda9e..5b54410 100644
--- a/grbl/planner.c
+++ b/grbl/planner.c
@@ -292,9 +292,9 @@ uint8_t plan_check_full_buffer()
       }
       block->step_event_count = max(block->step_event_count, block->steps[idx]);
       if (idx == A_MOTOR) {
-        delta_mm = ((target_steps[X_AXIS]-pl.position[X_AXIS]) + (target_steps[Y_AXIS]-pl.position[Y_AXIS]))/settings.steps_per_mm[idx];
+        delta_mm = (target_steps[X_AXIS]-pl.position[X_AXIS] + target_steps[Y_AXIS]-pl.position[Y_AXIS])/settings.steps_per_mm[idx];
       } else if (idx == B_MOTOR) {
-        delta_mm = ((target_steps[X_AXIS]-pl.position[X_AXIS]) - (target_steps[Y_AXIS]-pl.position[Y_AXIS]))/settings.steps_per_mm[idx];
+        delta_mm = (target_steps[X_AXIS]-pl.position[X_AXIS] - target_steps[Y_AXIS]+pl.position[Y_AXIS])/settings.steps_per_mm[idx];
       } else {
         delta_mm = (target_steps[idx] - pl.position[idx])/settings.steps_per_mm[idx];
       }
diff --git a/grbl/system.c b/grbl/system.c
index ff678f7..f16b8e8 100644
--- a/grbl/system.c
+++ b/grbl/system.c
@@ -288,12 +288,11 @@ void system_convert_array_steps_to_mpos(float *position, int32_t *steps)
 }
 
 
+// CoreXY calculation only. Returns x or y-axis "steps" based on CoreXY motor steps.
 int32_t system_convert_corexy_to_x_axis_steps(int32_t *steps)
 {
   return( (steps[A_MOTOR] + steps[B_MOTOR])/2 );
 }
-
-
 int32_t system_convert_corexy_to_y_axis_steps(int32_t *steps)
 {
   return( (steps[A_MOTOR] - steps[B_MOTOR])/2 );
diff --git a/grbl/system.h b/grbl/system.h
index 6774d54..09a3171 100644
--- a/grbl/system.h
+++ b/grbl/system.h
@@ -106,6 +106,7 @@ float system_convert_axis_steps_to_mpos(int32_t *steps, uint8_t idx);
 // Updates a machine 'position' array based on the 'step' array sent.
 void system_convert_array_steps_to_mpos(float *position, int32_t *steps);
 
+// CoreXY calculation only. Returns x or y-axis "steps" based on CoreXY motor steps.
 int32_t system_convert_corexy_to_x_axis_steps(int32_t *steps);
 int32_t system_convert_corexy_to_y_axis_steps(int32_t *steps);