From dcc3b6c21ee4ea4ff3192f8cee8ab623abfd9773 Mon Sep 17 00:00:00 2001
From: Christoph Fretter <christoph.fretter@gmail.com>
Date: Mon, 16 Aug 2021 20:47:33 +0200
Subject: [PATCH]  fix to homing

ported these changes to fix homing: https://github.com/grbl/grbl/pull/818/commits/22d1b2c8d1f15c642d2527807d7e26276489bf1a
---
 config.h |  7 ++++---
 limits.c | 21 +++++++++++++++++++--
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/config.h b/config.h
index 0b29492..8886ae6 100644
--- a/config.h
+++ b/config.h
@@ -55,7 +55,7 @@
 // If homing is enabled, homing init lock sets Grbl into an alarm state upon power up. This forces
 // the user to perform the homing cycle (or override the locks) before doing anything else. This is
 // mainly a safety feature to remind the user to home, since position is unknown to Grbl.
-#define HOMING_INIT_LOCK // Comment to disable
+//#define HOMING_INIT_LOCK // Comment to disable
 
 // Define the homing cycle patterns with bitmasks. The homing cycle first performs a search mode
 // to quickly engage the limit switches, followed by a slower locate mode, and finished by a short
@@ -74,7 +74,8 @@
 // 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)|(1<<Y_AXIS))
+#define HOMING_CYCLE_0 ((1<<X_AXIS))
+#define HOMING_CYCLE_1 ((1<<Y_AXIS))
 // #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.
@@ -150,7 +151,7 @@
 // defined at (http://corexy.com/theory.html). Motors are assumed to positioned and wired exactly as
 // described, if not, motions may move in strange directions. Grbl assumes the CoreXY A and B motors
 // have the same steps per mm internally.
-// #define COREXY // Default disabled. Uncomment to enable.
+#define COREXY // Default disabled. Uncomment to enable.
 
 // Inverts pin logic of the control command pins. This essentially means when this option is enabled
 // you can use normally-closed switches, rather than the default normally-open switches.
diff --git a/limits.c b/limits.c
index 65869d1..89ce8df 100644
--- a/limits.c
+++ b/limits.c
@@ -165,6 +165,12 @@ void limits_go_home(uint8_t cycle_mask)
     }
   }
 
+  #ifdef COREXY
+    sys.position[A_MOTOR] = 0;
+    sys.position[B_MOTOR] = 0;
+    plan_sync_position();
+  #endif
+
   // Set search mode with approach at seek rate to quickly engage the specified cycle_mask limit switches.
   bool approach = true;
   float homing_rate = settings.homing_seek_rate;
@@ -181,7 +187,12 @@ void limits_go_home(uint8_t cycle_mask)
       // Set target location for active axes and setup computation for homing rate.
       if (bit_istrue(cycle_mask,bit(idx))) {
         n_active_axis++;
-        sys.position[idx] = 0;
+           #ifndef COREXY
+          sys.position[idx] = 0;
+        #else
+          sys.position[A_MOTOR] = 0;
+          sys.position[B_MOTOR] = 0;
+        #endif
         // Set target direction based on cycle mask and homing cycle approach state.
         // NOTE: This happens to compile smaller than any other implementation tried.
         if (bit_istrue(settings.homing_dir_mask,bit(idx))) {
@@ -216,7 +227,13 @@ void limits_go_home(uint8_t cycle_mask)
 		limit_state = limits_get_state();
 		for (idx=0; idx<N_AXIS; idx++) {
 		  if (axislock & step_pin[idx]) {
-			if (limit_state & (1 << idx)) { axislock &= ~(step_pin[idx]); }
+			if (limit_state & (1 << idx)) {
+                      #ifndef COREXY
+                        axislock &= ~(step_pin[idx]);
+                      #else
+                        axislock &= ~(step_pin[A_MOTOR]|step_pin[B_MOTOR]);
+                      #endif
+                    }
 		  }
 		}
 		sys.homing_axis_lock = axislock;