stepper: quick accelerate

firmware/src/constants.h

@@ -39,3 +39,9 @@
 
 #define STEPPER_STEPS_PER_REV 200
 #define STEPPER_MICROSTEPS 2
+#define STEPPER_MM_PER_REV 0.5 // TODO: measure this
+
+#define MICROS_PER_TICK 16 // 16MHz / 256 = 62.5kHz = 16us per tick
+#define STEPPER_MIN_CADANCE 50 // speed measured in timer ticks per step (less is faster)
+#define STEPPER_MAX_CADANCE 12
+#define STEPPER_CADENCE_ACCEL_MS 3 // acceleration measured in ms per cadence increment/decrement

firmware/src/debug.cpp

@@ -58,6 +58,7 @@ void handleDebugFunctions(char key) {
     Serial.println("  l - change stepper direction to left");
     Serial.println("  r - change stepper direction to right");
     Serial.println("  - - toggle stepper timer");
+    Serial.println("  q - quick accelerate");
   } else if (key == 's') {
     happyBuzz();
     delay(500);
@@ -90,6 +91,8 @@ void handleDebugFunctions(char key) {
     setStepperDirection(RIGHT);
   } else if (key == '-') {
     setTimerEnabled(!isTimerEnabled());
+  } else if (key == 'q') {
+    quickAccelerate();
   }
 }
 

firmware/src/main.cpp

@@ -35,54 +35,9 @@ void setup() {
   splashScreen();
 }
 
-/*
-bool stepperDemo = false;
-bool stepperDemoSlowing = false;
-bool stepperDemoLongStretch = false;
-unsigned long lastStepperDemoMillis = 0;
-*/
-
 void loop() {
   debugScanI2C();
 
-/*
-  if (debugKey == 'k') {
-    setStepperEnabled(true);
-    setStepperDirection(RIGHT);
-    setTimerEnabled(true);
-    setTimerCadence(50);
-    stepperDemo = true;
-    stepperDemoSlowing = false;
-    stepperDemoLongStretch = false;
-    lastStepperDemoMillis = millis();
-  }
-
-  if (stepperDemo) {
-    auto now = millis();
-    if (now - lastStepperDemoMillis >= (stepperDemoLongStretch ? 1500 : 3)) {
-      lastStepperDemoMillis = now;
-      stepperDemoLongStretch = false;
-      auto cadence = getTimerCadence();
-
-      if (stepperDemoSlowing) {
-        if (cadence == 50) {
-          setStepperDirection(!getStepperDirection());
-          stepperDemoSlowing = false;
-        } else {
-          setTimerCadence(cadence + 1);
-        }
-      } else {
-        if (cadence == 12) {
-          stepperDemoLongStretch = true;
-          stepperDemoSlowing = true;
-        } else {
-          setTimerCadence(cadence - 1);
-        }
-      }
-    }
-  }
-*/
-
   auto input = getInput();
   if (input.hasInput) {
     tick();

firmware/src/stepper.cpp

@@ -93,3 +93,15 @@ inline void step() {
 ISR(TIMER1_COMPA_vect) {
   step();
 }
+
+void quickAccelerate() {
+  setStepperEnabled(true);
+  uint16_t cadence = STEPPER_MIN_CADANCE;
+  setTimerCadence(cadence);
+  setTimerEnabled(true);
+  while (cadence > STEPPER_MAX_CADANCE) {
+    delay(STEPPER_CADENCE_ACCEL_MS);
+    cadence--;
+    setTimerCadence(cadence);
+  }
+}

firmware/src/stepper.h

@@ -14,3 +14,6 @@ void setStepperEnabled(bool enabled);
 bool getStepperDirection();
 void setStepperDirection(bool dir);
 inline void step();
+
+/** Accelerates from 0 to max speed as quickly as possible, synchronously */
+void quickAccelerate();