diff --git a/inc/system/gpio.h b/inc/system/gpio.h
--- a/inc/system/gpio.h
+++ b/inc/system/gpio.h
@@ -4,6 +4,12 @@
 #include "stm32f3xx_hal.h"
 
 
+// Helper macros
+#define CHANGE_PERIOD_MS 100
+#define CHANGE_ELAPSED (HAL_GetTick() - change_time_reset) > CHANGE_PERIOD_MS
+#define CHANGE_RESET change_time_reset = HAL_GetTick()
+
+
 // Define button push
 #define SW_D_Pin GPIO_PIN_4
 #define SW_D_GPIO_Port GPIOA