diff --git a/RetroJoystickAdapter.ino b/RetroJoystickAdapter.ino
index 2d1ea0a..091cf3c 100644
--- a/RetroJoystickAdapter.ino
+++ b/RetroJoystickAdapter.ino
@@ -319,10 +319,10 @@ void interpretJoystickState(uint8_t j, uint8_t *status) {
 void setupJoysticks() {
   pinMode(LATCH1, OUTPUT);
   pinMode(CLOCK1, OUTPUT);
-  pinMode(DATA1, INPUT);
+  pinMode(DATA1, INPUT_PULLUP);
   pinMode(LATCH2, OUTPUT);
   pinMode(CLOCK2, OUTPUT);
-  pinMode(DATA2, INPUT);
+  pinMode(DATA2, INPUT_PULLUP);
 }
 
 #define latchlow digitalWrite(LATCH1, LOW); digitalWrite(LATCH2, LOW);