avoid compile error on sam and esp32 for oveTimed example

examples/MoveTimed/MoveTimed.ino

@@ -1,3 +1,4 @@
+#if defined(ARDUINO_ARCH_AVR)
 #include "AVRStepperPins.h"
 #include "FastAccelStepper.h"
 
@@ -15,6 +16,29 @@ FastAccelStepperEngine engine = FastAccelStepperEngine();
 FastAccelStepper *stepperX = NULL;
 FastAccelStepper *stepperY = NULL;
 
+struct control_s {
+  uint64_t time;
+  uint16_t phi;
+  bool is_running;
+  uint16_t drift;  // time delta in ticks
+};
+struct control_s controlX = {
+  .time = 0, .phi = 0, .is_running = false, .drift = 0
+};
+struct control_s controlY = {
+  .time = 0, .phi = 90, .is_running = false, .drift = 0
+};
+
+// This means, the circle is executed in 360*4ms = 1440ms
+#ifndef TIMESTEP_TICKS
+#define TIMESTEP_TICKS (TICKS_PER_S/4000)
+#endif
+
+// Table generated by python:
+// [int(math.sin(x*math.pi/180)*1600) for x in range(0,91)]
+int16_t steps[91] = { 0, 27, 55, 83, 111, 139, 167, 194, 222, 250, 277, 305, 332, 359, 387, 414, 441, 467, 494, 520, 547, 573, 599, 625, 650, 676, 701, 726, 751, 775, 799, 824, 847, 871, 894, 917, 940, 962, 985, 1006, 1028, 1049, 1070, 1091, 1111, 1131, 1150, 1170, 1189, 1207, 1225, 1243, 1260, 1277, 1294, 1310, 1326, 1341, 1356, 1371, 1385, 1399, 1412, 1425, 1438, 1450, 1461, 1472, 1483, 1493, 1503, 1512, 1521, 1530, 1538, 1545, 1552, 1558, 1565, 1570, 1575, 1580, 1584, 1588, 1591, 1593, 1596, 1597, 1599, 1599, 1600
+};
+
 void setup() {
   engine.init();
   stepperX = engine.stepperConnectToPin(stepPinStepperX);
@@ -30,6 +54,81 @@ void setup() {
   stepperY->setDirectionPin(dirPinStepperX);
   stepperY->setEnablePin(enablePinStepperY);
   stepperY->setAutoEnable(false);
+
+  // Without auto enable, need to enable manually both steppers
+  stepperX->enableOutputs();
+  stepperY->enableOutputs();
+
+  // Fill the queue with 1ms delay and start the queues.
+  stepperX->moveTimed(0,TICKS_PER_S/1000,NULL,false);
+  stepperY->moveTimed(0,TICKS_PER_S/1000,NULL,false);
+
+  // Start the queues. Currently best but not perfect synchronicity
+  stepperX->moveTimed(0,0,NULL,true);
+  stepperY->moveTimed(0,0,NULL,true);
 }
 
+void moveStepper(FastAccelStepper *stepper, struct control_s *control) {
+   if (control->phi == 360) {
+      control->phi = 0;
+   }
+
+   // The table contains only one quadrant
+   uint16_t index = control->phi;
+   bool negate = false;
+   if (index > 180) {
+      negate = true;
+      index = 360 - index;
+   }
+   if (index > 90) {
+      index = 180 - index;
+   }
+   int16_t position = steps[index];
+   if (negate) {
+      position = -position;
+   }
+   int32_t current_position = stepper->getPositionAfterCommandsCompleted();
+   if (!control->is_running) {
+      // we need to wait until current_position and position match
+      if (position != current_position) {
+         // just advance time and phi
+         control->time += TIMESTEP_TICKS;
+         control->phi += 1;
+         return;
+      }
+      control->is_running = true;
+   }
+   int32_t steps = position - current_position;
+   uint32_t actual;
+   int8_t rc;
+   uint32_t duration = TIMESTEP_TICKS + control->drift;
+   rc = stepper->moveTimed(steps,duration,&actual,true);
+   switch(rc) {
+     case MOVE_TIMED_EMPTY:
+         Serial.println("Empty");
+         /* fallthrough */
+     case MOVE_TIMED_OK:
+         control->drift = duration-actual;
+         control->time += actual;
+         control->phi += 1;
+         break;
+     case MOVE_TIMED_BUSY:
+         break;
+     case MOVE_TIMED_TOO_LARGE_ERROR:
+         Serial.println("Too large");
+         break;
+   }
+}
+
+void loop() {
+  if (controlX.time < controlY.time) {
+    moveStepper(stepperX, &controlX);
+  }
+  else {
+    moveStepper(stepperY, &controlY);
+  }
+}
+#else
+void setup() {}
 void loop() {}
+#endif