diff --git a/Core/Src/ui.c b/Core/Src/ui.c
index 21f3aec..8205f48 100644
--- a/Core/Src/ui.c
+++ b/Core/Src/ui.c
@@ -75,8 +75,8 @@ void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {
   last_state[idx_a] = state_a;
   last_state[idx_b] = state_b;
 
-  if (state_a == GPIO_PIN_RESET && state_b == GPIO_PIN_RESET) {
-    // Second falling edge, direction depends on which pin changed last
+  if (state_a == GPIO_PIN_SET && state_b == GPIO_PIN_SET) {
+    // Second rising edge, direction depends on which pin changed last
     if (a_changed && b_changed) {
       // This shouldn't happen. Ignore this event.
       last_change[idx_a] = now;