Motion/PulseGen: allow to abort a move for chaining

Add a new parameter "halt" (default to true) to control the stopping
behavior:

- halt=true: no subsequent moves will be planned, motions stops abruptly
- half=false: a new move will be chained after the current one

src/modules/motion.cpp

@@ -62,9 +62,9 @@ bool Motion::QueueEmpty() const {
     return true;
 }
 
-void Motion::AbortPlannedMoves() {
+void Motion::AbortPlannedMoves(bool halt) {
     for (uint8_t i = 0; i != NUM_AXIS; ++i)
-        axisData[i].ctrl.AbortPlannedMoves();
+        axisData[i].ctrl.AbortPlannedMoves(halt);
 }
 
 st_timer_t Motion::Step() {

src/modules/motion.h

@@ -240,7 +240,8 @@ public:
     bool Full(Axis axis) const { return axisData[axis].ctrl.Full(); }
 
     /// stop whatever moves are being done
-    void AbortPlannedMoves();
+    /// @param halt When true, also abruptly stop axis movement.
+    void AbortPlannedMoves(bool halt = true);
 
     /// @returns the TMC213 driver associated with the particular axis
     inline const hal::tmc2130::TMC2130 &DriverForAxis(Axis axis) const {

src/modules/pulse_gen.cpp

@@ -136,15 +136,20 @@ pos_t PulseGen::CurPosition() const {
     return cur_pos;
 }
 
-void PulseGen::AbortPlannedMoves() {
+void PulseGen::AbortPlannedMoves(bool halt) {
     // always update to effective position
     position = CurPosition();
 
     // destroy the current block
     if (current_block) {
+        last_rate = acc_step_rate;
         current_block = nullptr;
         block_index.pop();
     }
+
+    // truncate the last rate if halting
+    if (halt)
+        last_rate = 0;
 }
 
 } // namespace motor

src/modules/pulse_gen.h

@@ -44,7 +44,8 @@ public:
     bool PlanMoveTo(pos_t pos, steps_t feedrate);
 
     /// Stop whatever moves are being done
-    void AbortPlannedMoves();
+    /// @param halt When true, also abruptly stop axis movement.
+    void AbortPlannedMoves(bool halt = true);
 
     /// @returns the head position of the axis at the end of all moves
     pos_t Position() const { return position; }

tests/unit/logic/stubs/stub_motion.cpp

@@ -65,7 +65,7 @@ bool Motion::QueueEmpty() const {
     return true;
 }
 
-void Motion::AbortPlannedMoves() {
+void Motion::AbortPlannedMoves(bool halt) {
     for (uint8_t i = 0; i < 3; ++i) {
         axes[i].targetPos = axes[i].pos; // leave the axis where it was at the time of abort
     }