Added option to setting $63 to set spindle RPM to minimum (typically 0) on feed hold. Ref. issue #991.

Fixed reset (abort) not turning off laser in some circumstances.

README.md

@@ -1,6 +1,6 @@
 ## grblHAL ##
 
-Latest build date is 20260811, see the [changelog](changelog.md) for details.  
+Latest build date is 20260813, see the [changelog](changelog.md) for details.  
 
 > [!NOTE]
 >  A settings reset will be performed on an update of builds prior to 20241208. Backup and restore of settings is recommended.  

alarms.c

@@ -47,7 +47,8 @@ PROGMEM static const alarm_detail_t alarm_detail[] = {
     { Alarm_HomingFail, "Homing fail. Bad configuration." },
     { Alarm_ModbusException, "Modbus exception. Timeout or message error." },
     { Alarm_ExpanderException, "I/O expander communication failed." },
-    { Alarm_NVS_Failed, "Non Volatile Storage (EEPROM) failure." }
+    { Alarm_NVS_Failed, "Non Volatile Storage (EEPROM) failure." },
+    { Alarm_BufferOverflow, "Buffer overflow." }
 };
 
 static alarm_details_t details = {

alarms.h

@@ -3,7 +3,7 @@
 
   Part of grblHAL
 
-  Copyright (c) 2017-2025 Terje Io
+  Copyright (c) 2017-2026 Terje Io
   Copyright (c) 2011-2016 Sungeun K. Jeon for Gnea Research LLC
   Copyright (c) 2009-2011 Simen Svale Skogsrud
 
@@ -49,7 +49,8 @@ typedef enum {
     Alarm_ModbusException = 19,                 //!< 19
     Alarm_ExpanderException = 20,               //!< 20
     Alarm_NVS_Failed = 21,                      //!< 21
-    Alarm_AlarmMax = Alarm_NVS_Failed
+    Alarm_BufferOverflow = 22,                  //!< 22
+    Alarm_AlarmMax = Alarm_BufferOverflow
 } __attribute__ ((__packed__)) alarm_code_t;
 
 typedef struct {

changelog.md

@@ -1,5 +1,29 @@
 ## grblHAL changelog
 
+<a name="20260813">Build 20260813
+
+Core:
+
+* Added option to setting `$63` - _Feed hold actions_ to set spindle RPM to minimum \(typically 0\) on feed hold.
+Ref. issue [#991](https://github.com/grblHAL/core/issues/991).
+> [!NOTE]
+> This is ignored for laser enabled spindles when M4 is active.
+
+* Fixed reset \(abort\) not turning off laser in some circumstances.
+
+Drivers:
+
+* ESP32: fixed pin conflict with Modbus port for BTT Rodent board. Ref. [#211](https://github.com/grblHAL/ESP32/issues/211).
+Fixed issues with second PWM spindle.
+
+Plugins:
+
+* Laser, LigthBurn clusters: Added fix for for modal state RPM left incorrect after processing line.
+"Hardened" code to mostly ignore malformed/malign input, may raise alarm if really off the charts.
+Ref. PR[#4](/https://github.com/grblHAL/Plugins_laser/pull/4).
+
+---
+
 <a name="20260811">Build 20260811
 
 Core:

grbl.h

@@ -42,7 +42,7 @@
 #else
 #define GRBL_VERSION "1.1f"
 #endif
-#define GRBL_BUILD 20260811
+#define GRBL_BUILD 20260813
 
 #define GRBL_URL "https://github.com/grblHAL"
 

motion_control.c

@@ -179,10 +179,12 @@ bool mc_line (float *target, plan_line_data_t *pl_data)
         // Plan and queue motion into planner buffer.
         // While in M3 laser mode also set spindle state and force a buffer sync
         // if there is a coincident position passed.
-        if(!plan_buffer_line(target, pl_data) && pl_data->spindle.hal->cap.laser && pl_data->spindle.state.on && !pl_data->spindle.state.ccw) {
+        if(!plan_buffer_line(target, pl_data) &&
-            protocol_buffer_synchronize();
+            pl_data->spindle.hal->cap.laser &&
+             pl_data->spindle.state.on &&
+              !pl_data->spindle.state.ccw &&
+                protocol_buffer_synchronize())
             pl_data->spindle.hal->set_state(pl_data->spindle.hal, pl_data->spindle.state, pl_data->spindle.rpm);
-        }
 
 #ifdef KINEMATICS_API
         if(pl_data->condition.jog_motion) {

settings.c

@@ -1226,6 +1226,7 @@ static status_code_t set_hold_actions (setting_id_t id, uint_fast16_t int_value)
 {
     settings.flags.disable_laser_during_hold = bit_istrue(int_value, bit(0));
     settings.flags.restore_after_feed_hold = bit_istrue(int_value, bit(1));
+    settings.flags.set_rpm_0_during_hold = bit_istrue(int_value, bit(2));
 
     return Status_OK;
 }
@@ -1762,7 +1763,7 @@ FLASHMEM static uint32_t get_int (setting_id_t id)
             break;
 
         case Setting_HoldActions:
-            value = settings.flags.disable_laser_during_hold | (settings.flags.restore_after_feed_hold << 1);
+            value = settings.flags.disable_laser_during_hold | (settings.flags.restore_after_feed_hold << 1) | (settings.flags.set_rpm_0_during_hold << 2);
             break;
 
         case Setting_ForceInitAlarm:
@@ -2392,7 +2393,7 @@ PROGMEM static const setting_detail_t setting_detail[] = {
      { Setting_DoorOptions, Group_SafetyDoor, "Safety door options", NULL, Format_Bitfield, door_options, NULL, NULL, Setting_IsExtended, &settings.safety_door.flags.value, NULL, is_setting_available },
 #endif
      { Setting_SleepEnable, Group_General, "Sleep enable", NULL, Format_Bool, NULL, NULL, NULL, Setting_IsExtendedFn, set_sleep_enable, get_int, is_setting_available },
-     { Setting_HoldActions, Group_General, "Feed hold actions", NULL, Format_Bitfield, "Disable laser during hold,Restore spindle and coolant state on resume", NULL, NULL, Setting_IsExtendedFn, set_hold_actions, get_int, NULL },
+     { Setting_HoldActions, Group_General, "Feed hold actions", NULL, Format_Bitfield, "Disable laser during hold,Restore spindle and coolant state on resume,Set RPM to minimum (except for laser M4)", NULL, NULL, Setting_IsExtendedFn, set_hold_actions, get_int, NULL },
      { Setting_ForceInitAlarm, Group_General, "Force init alarm", NULL, Format_Bool, NULL, NULL, NULL, Setting_IsExtendedFn, set_force_initialization_alarm, get_int, NULL },
      { Setting_ProbingFlags, Group_Probing, "Probing options", NULL, Format_Bitfield, probing_options, NULL, NULL, Setting_IsExtendedFn, set_probe_flags, get_int, is_setting_available },
 #if ENABLE_SPINDLE_LINEARIZATION

settings.h

@@ -611,7 +611,8 @@ typedef union {
                  m98_prescan_enable              :1,
                  rotary_fix_enable               :1,
                  revert_metric_conversion        :1, // For rotary axes inch/min -> mm/min
-                 unassigned                      :6;
+                 set_rpm_0_during_hold       :1,
+                 unassigned                      :5;
     };
 } settingflags_t;
 

spindle_control.c

@@ -845,11 +845,13 @@ FLASHMEM bool spindle_restore (spindle_ptrs_t *spindle, spindle_state_t state, f
 {
     bool ok;
 
-    if(spindle->cap.laser) { // When in laser mode, ignore spindle spin-up delay. Set to turn on laser when cycle starts.
+    if(!spindle->param->option.restore_rpm && spindle->cap.laser) { // When in laser mode, ignore spindle spin-up delay. Set to turn on laser when cycle starts.
         if(!(ok = !settings.flags.disable_laser_during_hold))
             ok = (sys.step_control.update_spindle_rpm = _spindle_set_state(spindle, state, 0.0f, 0));
-    } else if(!(ok = spindle_check_state(spindle, state) && spindle->param->rpm == rpm))
+    } else if(!(ok = !spindle->param->option.restore_rpm && spindle_check_state(spindle, state) && spindle->param->rpm == rpm)) {
         ok = spindle_set_state_wait(spindle, state, rpm, delay_ms);
+        spindle->param->option.restore_rpm = Off;
+    }
 
     return ok;
 }
@@ -889,6 +891,7 @@ FLASHMEM void spindle_all_off (bool reset)
 
             spindle->param->rpm = spindle->param->rpm_overridden = 0.0f;
             spindle->param->state.value = 0;
+            spindle->param->option.restore_rpm = Off;
 #ifdef GRBL_ESP32
             spindle->esp32_off(spindle);
 #else

spindle_control.h

@@ -364,7 +364,8 @@ typedef struct spindle_param {
         uint8_t ramp_up          :1,
                 ramp_down        :1,
                 ignore_delays    :1,
-                override_disable :1;
+                override_disable :1,
+                restore_rpm      :1;
     } option;
     spindle_ptrs_t *hal;
 } spindle_param_t;

state_machine.c

@@ -370,13 +370,13 @@ void state_set (sys_state_t new_state)
 // Suspend manager. Controls spindle overrides in hold states.
 FLASHMEM void state_suspend_manager (void)
 {
-    if(stateHandler != state_await_resume || !gc_spindle_get(0)->state.on)
+    spindle_t *spindle = &restore_condition.spindle[restore_condition.spindle_num];
+
+    if(stateHandler != state_await_resume || !gc_spindle_get(0)->state.on || (spindle->hal && spindle->hal->param->option.restore_rpm))
         return;
 
     if(sys.override.spindle_stop.value) {
 
-        spindle_t *spindle = &restore_condition.spindle[restore_condition.spindle_num];
-
         // Handles beginning of spindle stop
         if(sys.override.spindle_stop.initiate) {
             sys.override.spindle_stop.value = 0; // Clear stop override state
@@ -399,9 +399,9 @@ FLASHMEM void state_suspend_manager (void)
                 grbl.on_override_changed(OverrideChanged_SpindleState);
         }
 
-    } else if(sys.step_control.update_spindle_rpm && restore_condition.spindle[0].hal->get_state(restore_condition.spindle[0].hal).on) {
+    } else if(sys.step_control.update_spindle_rpm && spindle->hal && spindle->hal->get_state(spindle->hal).on) {
         // Handles spindle state during hold. NOTE: Spindle speed overrides may be altered during hold state.
-        state_spindle_restore(&restore_condition.spindle[restore_condition.spindle_num], settings.spindle.on_delay);
+        state_spindle_restore(spindle, settings.spindle.on_delay);
         sys.step_control.update_spindle_rpm = Off;
     }
 }
@@ -595,6 +595,18 @@ FLASHMEM static void state_await_hold (uint_fast16_t rt_exec)
                 sys.flags.is_parking = false;
                 break;
 
+            case STATE_HOLD:
+                {
+                    spindle_t *spindle;
+                    if((spindle = &restore_condition.spindle[restore_condition.spindle_num])->hal && settings.flags.set_rpm_0_during_hold) {
+                        if(spindle->state.on && !(spindle->hal->cap.laser && spindle->state.ccw)) {
+                            spindle->hal->param->option.restore_rpm = settings.flags.restore_after_feed_hold;
+                            spindle->hal->set_state(spindle->hal, spindle->state, spindle->hal->rpm_min);
+                        }
+                    }
+                }
+                break;
+
             default:
                 break;
         }
@@ -674,18 +686,19 @@ FLASHMEM static void state_await_resume (uint_fast16_t rt_exec)
                 break;
 
             default:
-                if (!settings.flags.restore_after_feed_hold) {
+                if(!settings.flags.restore_after_feed_hold) {
                     if (!restore_condition.spindle[restore_condition.spindle_num].hal->get_state(restore_condition.spindle[restore_condition.spindle_num].hal).on)
                         gc_spindle_off();
                     sys.override.spindle_stop.value = 0; // Clear spindle stop override states
                 } else {
 
-                    if (restore_condition.spindle[restore_condition.spindle_num].state.on != restore_condition.spindle[restore_condition.spindle_num].hal->get_state(restore_condition.spindle[restore_condition.spindle_num].hal).on) {
+                    spindle_t *spindle;
+                    if((spindle = &restore_condition.spindle[restore_condition.spindle_num])->hal && (spindle->hal->param->option.restore_rpm || spindle->state.on != spindle->hal->get_state(spindle->hal).on)) {
                         grbl.report.feedback_message(Message_SpindleRestore);
-                        state_spindle_restore(&restore_condition.spindle[restore_condition.spindle_num], settings.spindle.on_delay);
+                        state_spindle_restore(spindle, settings.spindle.on_delay);
                     }
 
-                    if (restore_condition.coolant.value != hal.coolant.get_state().value) {
+                    if(restore_condition.coolant.value != hal.coolant.get_state().value) {
                         // NOTE: Laser mode will honor this delay. An exhaust system is often controlled by coolant signals.
                         coolant_restore(restore_condition.coolant, settings.coolant.on_delay);
                         gc_coolant(restore_condition.coolant);