diff --git a/Joystick.cpp b/Joystick.cpp
index 3f5a1d9..439c3c5 100644
--- a/Joystick.cpp
+++ b/Joystick.cpp
@@ -37,6 +37,7 @@ void Joystick::AddButton(uint8_t pin, ButtonType type, bool pullup) {
   _buttons[_num_buttons].pin = pin;
   _buttons[_num_buttons].type = type;
   _buttons[_num_buttons].last_state = digitalRead(pin);
+  _buttons[_num_buttons].pullup = pullup;
   _num_buttons++;
 
   if (type & _BUTTON_PULSED_TYPES) _have_pulsed_button = true;
@@ -63,23 +64,19 @@ void Joystick::Update() {
   JoyReport oldReport = _joyReport;
   
   for (int i = 0; i < _num_buttons; i++) {
-    uint8_t value = digitalRead(_buttons[i].pin);
-    // TODO: handle button according to ButtonType
+    _UpdateButton(_buttons[i], i);
   }
 
   for (int i = 0; i < _num_axes; i++) {
-    uint16_t value = analogRead(_axes[i]);
-    // TODO: convert raw analog value to something sensible for
-    //   HID Analog data.
+    _UpdateAxis(i);
   }
 
   if (_joyReport != oldReport) {
     Write();
-  }
-
-  if (_have_pulsed_button) {
-    _ReleasePulsedButtons();
-    Write();
+    if (_have_pulsed_button) {
+      _ReleasePulsedButtons();
+      Write();
+    }
   }
 }
 
@@ -125,3 +122,36 @@ void Joystick::Write() {
   Serial.write((uint8_t *)&_joyReport, sizeof(JoyReport));
   delay(250);
 }
+
+void Joystick::_UpdateButton(Button& button, uint8_t index) {
+  uint8_t value = digitalRead(button.pin);
+  // Treat pullup-resistor inputs as basically backwards.
+  if (button.pullup) {
+    if (value == LOW) value = HIGH;
+    else value = LOW;
+  }
+    
+  switch (button.type) {
+    case BUTTON_MAINTAINED:
+      if (value == HIGH) PressButton(index);
+      else ReleaseButton(index);
+      break;
+    case BUTTON_PULSED:
+      if (value == HIGH && button.last_state == LOW) PressButton(index);
+      break;
+    case BUTTON_PULSED_DOUBLE_ACTION:
+      if (value != button.last_state) PressButton(index);
+      break;
+    default:
+      if (_debug) {
+        Serial.print("DEBUG: Unhandled button type: ");
+        Serial.println(button.type);
+      }
+  }
+  
+  button.last_state = value;
+}
+
+void Joystick::_UpdateAxis(uint8_t index) {
+  if (_debug) Serial.println("STUB: Joystick::_UpdateAxis");
+}
diff --git a/Joystick.h b/Joystick.h
index 745f9c4..11b1cb4 100644
--- a/Joystick.h
+++ b/Joystick.h
@@ -20,10 +20,17 @@ enum ButtonType {
   BUTTON_PULSED_DOUBLE_ACTION = 0x4
 };
 
-typedef struct JoyReport {
+struct JoyReport {
   int16_t axis[JOYSTICK_NUM_AXES];
   uint8_t button[JOYSTICK_NUM_BYTES];
-} ;
+};
+
+struct Button {
+  uint8_t pin;
+  ButtonType type;
+  uint8_t last_state;
+  bool pullup;
+};
 
 bool operator ==(JoyReport a, JoyReport b);
 bool operator !=(JoyReport a, JoyReport b);
@@ -47,12 +54,10 @@ class Joystick {
 
   private:
     void _ReleasePulsedButtons();
+    void _UpdateButton(Button& button, uint8_t index);
+    void _UpdateAxis(uint8_t index);
     
-    struct {
-      uint8_t pin;
-      ButtonType type;
-      uint8_t last_state;
-    } _buttons[JOYSTICK_NUM_BUTTONS];
+    Button _buttons[JOYSTICK_NUM_BUTTONS];
     uint8_t _num_buttons;
     bool _have_pulsed_button;