Fix for random feed hold/cycle start sequence failures. Ref. issue #491.

README.md

@@ -13,7 +13,7 @@ It has been written to complement grblHAL and has features such as proper keyboa
 
 ---
 
-Latest build date is 20240404, see the [changelog](changelog.md) for details.  
+Latest build date is 20240416, see the [changelog](changelog.md) for details.  
 
 __NOTE:__ Build 20240222 has moved the probe input to the ioPorts pool of inputs and will be allocated from it when configured.
 The change is major and _potentially dangerous_, it may damage your probe, so please _verify correct operation_ after installing this, or later, builds.

changelog.md

@@ -1,10 +1,26 @@
 ## grblHAL changelog
 
+<a name="20240416"/>Build 20240416
+
+Core:
+
+* Fix for random feed hold/cycle start sequence failures. Ref. issue [#491](https://github.com/grblHAL/core/issues/491).
+
+Drivers:
+
+* STM32F1xx: added tentative support for UART4, not tested!
+
+* STM32F7xx: added support for SPI4, not tested!
+
+* Simulator: added support for continuous 1ms systick event. Ref issue [#8](https://github.com/grblHAL/Simulator/issues/8).
+
+---
+
 <a name="20240408"/>Build 20240408
 
 Core:
 
-* Fix for bug in NGC expressions return statement handling. Ref issue [#485](https://github.com/grblHAL/core/issues/485).
+* Fix for bug in NGC expressions return statement handling. Ref. issue [#485](https://github.com/grblHAL/core/issues/485).
 
 Drivers:
 

grbl.h

@@ -42,7 +42,7 @@
 #else
 #define GRBL_VERSION "1.1f"
 #endif
-#define GRBL_BUILD 20240408
+#define GRBL_BUILD 20240416
 
 #define GRBL_URL "https://github.com/grblHAL"
 

planner.c

@@ -637,8 +637,8 @@ void plan_cycle_reinitialize (void)
 {
     // Re-plan from a complete stop. Reset planner entry speeds and buffer planned pointer.
     st_update_plan_block_parameters();
-    block_buffer_planned = block_buffer_tail;
-    planner_recalculate();
+    if((block_buffer_planned = block_buffer_tail) != block_buffer_head)
+        planner_recalculate();
 }
 
 // Re-calculates buffered motions profile parameters upon a motion-based override change.

stepper.c

@@ -7,18 +7,18 @@
   Copyright (c) 2011-2016 Sungeun K. Jeon for Gnea Research LLC
   Copyright (c) 2009-2011 Simen Svale Skogsrud
 
-  Grbl is free software: you can redistribute it and/or modify
+  grblHAL is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
-  Grbl is distributed in the hope that it will be useful,
+  grblHAL is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
-  along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
+  along with grblHAL. If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include <math.h>
@@ -748,11 +748,11 @@ void st_prep_buffer (void)
                 prep.ramp_type = Ramp_Decel;
                 // Compute decelerate distance relative to end of block.
                 float decel_dist = pl_block->millimeters - inv_2_accel * pl_block->entry_speed_sqr;
-                if (decel_dist < 0.0f) {
+                if(decel_dist < -0.0001f) {
                     // Deceleration through entire planner block. End of feed hold is not in this block.
                     prep.exit_speed = sqrtf(pl_block->entry_speed_sqr - 2.0f * pl_block->acceleration * pl_block->millimeters);
                 } else {
-                    prep.mm_complete = decel_dist; // End of feed hold.
+                    prep.mm_complete = decel_dist < 0.0001f ? 0.0f : decel_dist; // End of feed hold.
                     prep.exit_speed = 0.0f;
                 }
             } else { // [Normal Operation]