Fixes for backlash compensation: no longer resets current direction on a soft reset/stop, added handling of backlash setting changes per axis.

README.md

@@ -11,7 +11,7 @@ It has been written to complement grblHAL and has features such as proper keyboa
 
 ---
 
-Latest build date is 20220131, see the [changelog](changelog.md) for details.  
+Latest build date is 20220210, see the [changelog](changelog.md) for details.  
 __NOTE:__ A settings reset will be performed on an update for versions earlier than 20211122. Backup and restore of settings is recommended.  
 __IMPORTANT!__  A new setting has been introduced for ganged axes motors in version 20211121.  
 I have only bench tested this for a couple of drivers, correct function should be verified after updating by those who have more than three motors configured.  
@@ -83,4 +83,4 @@ List of Supported G-Codes:
 Some [plugins](https://github.com/grblHAL/plugins) implements additional M-codes.
 
 ---
-2022-01-23
+2022-02-10

changelog.md

@@ -1,5 +1,13 @@
 ## grblHAL changelog
 
+Build 20220210:
+
+Core:
+
+* Fixes for backlash compensation: no longer resets current direction on a soft reset/stop, added handling of backlash setting changes per axis.
+
+---
+
 20220209:
 
 Plugins:

grbl.h

@@ -34,7 +34,7 @@
 #else
 #define GRBL_VERSION "1.1f"
 #endif
-#define GRBL_BUILD 20220204
+#define GRBL_BUILD 20220210
 
 // The following symbols are set here if not already set by the compiler or in config.h
 // Do NOT change here!

grbllib.c

@@ -263,9 +263,7 @@ int grbl_enter (void)
         plan_reset();                   // Clear block buffer and planner variables
         st_reset();                     // Clear stepper subsystem variables.
         limits_set_homing_axes();       // Set axes to be homed from settings.
-#ifdef ENABLE_BACKLASH_COMPENSATION
-        mc_backlash_init();             // Init backlash configuration.
-#endif
+
         // Sync cleared gcode and planner positions to current system position.
         sync_position();
 

limits.c

@@ -3,7 +3,7 @@
 
   Part of grblHAL
 
-  Copyright (c) 2017-2021 Terje Io
+  Copyright (c) 2017-2022 Terje Io
   Copyright (c) 2012-2016 Sungeun K. Jeon for Gnea Research LLC
   Copyright (c) 2009-2011 Simen Svale Skogsrud
 
@@ -454,7 +454,7 @@ static bool limits_homing_cycle (axes_signals_t cycle, axes_signals_t auto_squar
 #endif
 
 #ifdef ENABLE_BACKLASH_COMPENSATION
-    mc_backlash_init();
+    mc_backlash_init(cycle);
 #endif
     sys.step_control.flags = 0; // Return step control to normal operation.
     sys.homed.mask |= cycle.mask;

motion_control.c

@@ -59,22 +59,20 @@
 #ifdef ENABLE_BACKLASH_COMPENSATION
 
 static float target_prev[N_AXIS];
-static axes_signals_t dir_negative, backlash_enabled;
+static axes_signals_t dir_negative = {0}, backlash_enabled = {0};
 
-void mc_backlash_init (void)
+void mc_backlash_init (axes_signals_t axes)
 {
     uint_fast8_t idx = N_AXIS;
 
-    backlash_enabled.mask = dir_negative.value = 0;
-
     do {
-        if(settings.axis[--idx].backlash > 0.0001f)
-            backlash_enabled.mask |= bit(idx);
-        dir_negative.value |= bit(idx);
+        idx--;
+        if(bit_istrue(axes.mask, bit(idx))) {
+            BIT_SET(backlash_enabled.mask, bit(idx), settings.axis[idx].backlash > 0.0001f);
+            BIT_SET(dir_negative.mask, bit(idx), bit_isfalse(settings.homing.dir_mask.mask, bit(idx)));
+        }
     } while(idx);
 
-    dir_negative.value ^= settings.homing.dir_mask.value;
-
     mc_sync_backlash_position();
 }
 

motion_control.h

@@ -3,7 +3,7 @@
 
   Part of grblHAL
 
-  Copyright (c) 2017-2019 Terje Io
+  Copyright (c) 2017-2022 Terje Io
   Copyright (c) 2011-2016 Sungeun K. Jeon for Gnea Research LLC
   Copyright (c) 2009-2011 Simen Svale Skogsrud
 
@@ -75,7 +75,7 @@ void mc_cubic_b_spline(float *target, plan_line_data_t *pl_data, float *position
 void mc_reset (void);
 
 #ifdef ENABLE_BACKLASH_COMPENSATION
-void mc_backlash_init (void);
+void mc_backlash_init (axes_signals_t axes);
 void mc_sync_backlash_position (void);
 #endif
 

planner.c

@@ -3,7 +3,7 @@
 
   Part of grblHAL
 
-  Copyright (c) 2017-2021 Terje Io
+  Copyright (c) 2017-2022 Terje Io
   Copyright (c) 2011-2016 Sungeun K. Jeon for Gnea Research LLC
   Copyright (c) 2009-2011 Simen Svale Skogsrud
   Copyright (c) 2011 Jens Geisler
@@ -32,13 +32,15 @@
 #ifdef KINEMATICS_API
 #include "kinematics.h"
 #endif
-
 #ifndef MINIMUM_JUNCTION_SPEED
 #define MINIMUM_JUNCTION_SPEED 0.0f
 #endif
 #ifndef MINIMUM_FEED_RATE
 #define MINIMUM_FEED_RATE 1.0f
 #endif
+#ifdef ENABLE_BACKLASH_COMPENSATION
+void mc_sync_backlash_position (void);
+#endif
 
 static plan_block_t block_buffer[BLOCK_BUFFER_SIZE];    // A ring buffer for motion instructions
 static plan_block_t *block_buffer_tail = NULL;          // Pointer to the block to process now
@@ -542,6 +544,9 @@ bool plan_buffer_line (float *target, plan_line_data_t *pl_data)
 void plan_sync_position ()
 {
     memcpy(pl.position, sys.position, sizeof(pl.position));
+#ifdef ENABLE_BACKLASH_COMPENSATION
+    mc_sync_backlash_position();
+#endif
 }
 
 

settings.c

@@ -1106,7 +1106,12 @@ static status_code_t set_axis_setting (setting_id_t setting, float value)
 
         case Setting_AxisBacklash:
 #ifdef ENABLE_BACKLASH_COMPENSATION
-            settings.axis[idx].backlash = value;
+            if(settings.axis[idx].backlash != value) {
+                axes_signals_t axes;
+                axes.mask = bit(idx);
+                settings.axis[idx].backlash = value;
+                mc_backlash_init(axes);
+            }
 #else
             status = Status_SettingDisabled;
 #endif
@@ -1619,7 +1624,9 @@ void settings_restore (settings_restore_t restore)
         settings.control_invert.mask &= hal.signals_cap.mask;
         settings.spindle.invert.ccw &= hal.driver_cap.spindle_dir;
         settings.spindle.invert.pwm &= hal.driver_cap.spindle_pwm_invert;
-
+#ifdef ENABLE_BACKLASH_COMPENSATION
+        mc_backlash_init((axes_signals_t){AXES_BITMASK});
+#endif
         settings_write_global();
     }
 
@@ -2153,10 +2160,6 @@ status_code_t settings_store_setting (setting_id_t id, char *svalue)
         if(set->save)
             set->save();
 
-#ifdef ENABLE_BACKLASH_COMPENSATION
-        mc_backlash_init();
-#endif
-
         if(set->on_changed)
             set->on_changed(&settings);
 
@@ -2191,7 +2194,7 @@ void settings_init (void)
 #endif
         report_init();
 #ifdef ENABLE_BACKLASH_COMPENSATION
-        mc_backlash_init();
+        mc_backlash_init((axes_signals_t){AXES_BITMASK});
 #endif
         hal.settings_changed(&settings);
 

state_machine.c

@@ -363,9 +363,6 @@ static void state_await_motion_cancel (uint_fast16_t rt_exec)
             plan_reset();
             st_reset();
             sync_position();
-#ifdef ENABLE_BACKLASH_COMPENSATION
-            mc_sync_backlash_position();
-#endif
             sys.suspend = false;
         }
         state_set(pending_state);