add start parameter to moveTimed

Author: gin66

src/FastAccelStepper.cpp

@@ -912,8 +912,14 @@ int32_t FastAccelStepper::getCurrentPosition() {
   return fas_queue[_queue_num].getCurrentPosition();
 }
 int8_t FastAccelStepper::moveTimed(int16_t steps, uint32_t duration,
-                                   uint32_t& actual_duration) {
-  // For now only a very crude implementation
+                                   uint32_t& actual_duration,
+				   bool start) {
+  if ((steps == 0) && (duration == 0)) {
+      if (start) {
+         addQueueEntry(NULL, true); // start the queue
+      }
+      return MOVE_TIMED_OK;
+  }
   uint8_t freeEntries = QUEUE_LEN - queueEntries();
   actual_duration = 0;
   struct stepper_command_s cmd = {.ticks = 0, .steps = 0, .count_up = true};
@@ -937,7 +943,7 @@ int8_t FastAccelStepper::moveTimed(int16_t steps, uint32_t duration,
         // cmd.
         cmd.ticks = duration >> 1;
       }
-      uint8_t ret = addQueueEntry(&cmd);
+      uint8_t ret = addQueueEntry(&cmd,start);
       if (ret != 0) {
         // unexpected
         return ret;
@@ -988,7 +994,7 @@ int8_t FastAccelStepper::moveTimed(int16_t steps, uint32_t duration,
         }
         this_duration -= cmd.ticks;
 
-        uint8_t ret = addQueueEntry(&cmd);
+        uint8_t ret = addQueueEntry(&cmd,start);
         if (ret != 0) {
           // unexpected
           return ret;
@@ -1032,7 +1038,7 @@ int8_t FastAccelStepper::moveTimed(int16_t steps, uint32_t duration,
          printf("increase ticks for %d steps\n", steps);
       #endif
     }
-    uint8_t ret = addQueueEntry(&cmd);
+    uint8_t ret = addQueueEntry(&cmd,start);
     if (ret != 0) {
       // unexpected
       return ret;

src/FastAccelStepper.h

@@ -622,13 +622,18 @@ class FastAccelStepper {
 // The main purpose is to bypass the ramp generator as mentioned in
 // [#299](https://github.com/gin66/FastAccelStepper/issues/299).
 // This shall allow to run consecutive small moves with fixed speed.
-// The parameters are distance (which can be 0) and duration in ticks.
-// Distance 0 makes sense in order to keep the time running and not
+// The parameters are steps (which can be 0) and duration in ticks.
+// steps=0 makes sense in order to keep the time running and not
 // getting out of sync.
 // Due to integer arithmetics the actual duration may be off by a small value.
 // That's why the actual_duration in TICKS is returned.
 // The application should consider this for the next runTimed move.
 //
+// The optional parameter is a boolean called start. This allows for the first
+// invocation to not start the queue yet. This is for managing steppers in parallel.
+// It allows to fill all steppers' queues and then kick it off by a call to
+// `moveTimed(0,0,true)`. Successive invocations can keep true.
+//
 // In order to not have another lightweight ramp generator running in
 // background interrupt, the expecation to the application is, that this
 // function is frequently enough called without the queue being emptied.
@@ -656,7 +661,7 @@ class FastAccelStepper {
 #define MOVE_TIMED_BUSY ((int8_t)5)
 #define MOVE_TIMED_EMPTY ((int8_t)6)
 #define MOVE_TIMED_TOO_LARGE_ERROR ((int8_t)-4)
-  int8_t moveTimed(int16_t steps, uint32_t duration, uint32_t& actual_duration);
+  int8_t moveTimed(int16_t steps, uint32_t duration, uint32_t& actual_duration, bool start = true);
 
   // ## Low Level Stepper Queue Management (low level access)
   //