Add a trivial example script and some formatting.

examples/hardware_test/hardware_test.ino

@@ -0,0 +1,86 @@
+#include "gravity.h"
+
+byte idx = 0;
+bool reversed = false;
+bool freeze = false;
+byte selected_param = 0;
+
+// Initialize the gravity library and attach your handlers in the setup method.
+void setup() {
+    // Initialize Gravity.
+    gravity.Init();
+
+    // Attach handlers.
+    gravity.clock.AttachIntHandler(IntClock);
+    gravity.encoder.AttachRotateHandler(HandleRotate);
+    gravity.encoder.AttachPressHandler(ChangeSelectedParam);
+    gravity.play_button.AttachPressHandler(HandlePlayPressed);
+
+    // Initial state.
+    gravity.outputs[idx].High();
+}
+
+// The loop method must always call `gravity.Process()` to read any peripherial state changes.
+void loop() {
+    gravity.Process();
+    freeze = gravity.shift_button.On();
+    UpdateDisplay();
+}
+
+// The rest of the code is your apps logic!
+
+void IntClock(uint32_t tick) {
+    if (tick % 12 == 0  && ! freeze) {
+        gravity.outputs[idx].Low();
+        if (reversed) {
+            idx = (idx == 0) ? OUTPUT_COUNT - 1 : idx - 1;
+        } else {
+            idx = (idx + 1) % OUTPUT_COUNT;
+        }
+        gravity.outputs[idx].High();
+    }
+}
+
+void HandlePlayPressed() {
+    gravity.clock.Pause();
+    if (gravity.clock.IsPaused()) {
+        for (int i = 0; i < OUTPUT_COUNT; i++) {
+            gravity.outputs[i].Low();
+        }
+    }
+}
+
+void HandleRotate(Direction dir, int val) {
+    if (selected_param == 0) {
+        gravity.clock.SetTempo(gravity.clock.Tempo() + val);
+    } else if (selected_param == 1) {
+        reversed = (dir == DIRECTION_DECREMENT);
+    }
+}
+
+void ChangeSelectedParam() {
+    selected_param = (selected_param + 1) % 2;
+}
+
+void UpdateDisplay() {
+    gravity.display.clearDisplay();
+
+    if (freeze) {
+        gravity.display.setCursor(42, 30);
+        gravity.display.print("FREEZE!");
+        gravity.display.display();
+        return;
+    }
+
+    gravity.display.setCursor(10, 0);
+    gravity.display.print("Tempo: ");
+    gravity.display.print(gravity.clock.Tempo());
+
+    gravity.display.setCursor(10, 10);
+    gravity.display.print("Direction: ");
+    gravity.display.print((reversed) ? "Backward" : "Forward");
+
+    gravity.display.drawChar(0, selected_param * 10, 0x10, 1, 0, 1);
+
+    gravity.display.display();
+}