diff --git a/Core/Inc/main.h b/Core/Inc/main.h
index 015253f..6412d63 100644
--- a/Core/Inc/main.h
+++ b/Core/Inc/main.h
@@ -41,12 +41,11 @@ extern "C" {
 
 /* Exported constants --------------------------------------------------------*/
 /* USER CODE BEGIN EC */
-
 /* USER CODE END EC */
 
 /* Exported macro ------------------------------------------------------------*/
 /* USER CODE BEGIN EM */
-
+#define MAIN_LOOP_PERIOD 100 /* ms */
 /* USER CODE END EM */
 
 /* Exported functions prototypes ---------------------------------------------*/
@@ -54,6 +53,7 @@ void Error_Handler(void);
 
 /* USER CODE BEGIN EFP */
 void update_status_leds();
+void delay_period();
 /* USER CODE END EFP */
 
 /* Private defines -----------------------------------------------------------*/
diff --git a/Core/Src/main.c b/Core/Src/main.c
index b74aede..339a1e2 100644
--- a/Core/Src/main.c
+++ b/Core/Src/main.c
@@ -85,6 +85,19 @@ void update_status_leds() {
     HAL_GPIO_WritePin(STAT_LED2_GPIO_Port, STAT_LED2_Pin, GPIO_PIN_SET);
   }
 }
+
+void delay_period() {
+  static uint32_t last_it = 0;
+  uint32_t now = HAL_GetTick();
+  int32_t diff = now - last_it;
+  if (diff > 100) {
+    HAL_GPIO_WritePin(STAT_LED3_GPIO_Port, STAT_LED3_Pin, GPIO_PIN_SET);
+  } else {
+    HAL_GPIO_WritePin(STAT_LED3_GPIO_Port, STAT_LED3_Pin, GPIO_PIN_RESET);
+    HAL_Delay(100 - diff);
+  }
+  last_it = now;
+}
 /* USER CODE END 0 */
 
 /**
@@ -136,6 +149,7 @@ int main(void) {
     /* USER CODE BEGIN 3 */
     update_status_leds();
     afe_measure();
+    delay_period();
   }
   /* USER CODE END 3 */
 }