diff --git a/Core/Inc/stm32f4xx_it.h b/Core/Inc/stm32f4xx_it.h
index dfd1d7d..b9be200 100644
--- a/Core/Inc/stm32f4xx_it.h
+++ b/Core/Inc/stm32f4xx_it.h
@@ -37,6 +37,7 @@ extern "C" {
 
 /* Exported constants --------------------------------------------------------*/
 /* USER CODE BEGIN EC */
+extern volatile uint32_t SysTickCnt;
 
 /* USER CODE END EC */
 
@@ -57,6 +58,9 @@ void PendSV_Handler(void);
 void SysTick_Handler(void);
 /* USER CODE BEGIN EFP */
 
+uint32_t SysTimeGetAbs(void);
+int32_t  SysTimeGetRel(uint32_t tref);
+
 /* USER CODE END EFP */
 
 #ifdef __cplusplus
diff --git a/Core/Src/main.c b/Core/Src/main.c
index fc537e2..8f27755 100644
--- a/Core/Src/main.c
+++ b/Core/Src/main.c
@@ -74,6 +74,20 @@ void printf_putc(void *p, char c) {
    Usart1_PutByte(c);
 }
 
+/***************************************************************************//**
+ * @brief Check if specified time interval has elapsed
+ * @param tref Pointer to time reference variable
+ * @param tcycle Time interval in milliseconds
+ *//****************************************************************************/
+static inline uint32_t TickChk(uint32_t *tref, int_fast16_t tcycle) {
+   int32_t tdif = SysTickCnt - *tref;
+   if (tdif >= tcycle) {
+      *tref += tcycle;
+      return 1;
+   }
+   return 0;
+}
+
 /* USER CODE END 0 */
 
 /**
@@ -120,6 +134,14 @@ int main(void) {
    /* Infinite loop */
    /* USER CODE BEGIN WHILE */
    while (1) {
+      static uint32_t Tick10msRef = 0;
+      if (TickChk(&Tick10msRef, 10)) {
+      }
+
+      static uint32_t Tick1secRef = 0;
+      if (TickChk(&Tick1secRef, 1000)) {
+      }
+
       int c;
 
       c = Usart2_GetByte();
diff --git a/Core/Src/stm32f4xx_it.c b/Core/Src/stm32f4xx_it.c
index bc9c66c..67b2c32 100644
--- a/Core/Src/stm32f4xx_it.c
+++ b/Core/Src/stm32f4xx_it.c
@@ -41,6 +41,7 @@
 
 /* Private variables ---------------------------------------------------------*/
 /* USER CODE BEGIN PV */
+volatile uint32_t SysTickCnt = 0;
 
 /* USER CODE END PV */
 
@@ -52,6 +53,22 @@
 /* Private user code ---------------------------------------------------------*/
 /* USER CODE BEGIN 0 */
 
+/***************************************************************************//**
+* @brief Get absolute system time
+*//****************************************************************************/
+uint32_t SysTimeGetAbs (void) {
+   return SysTickCnt;
+}
+
+/***************************************************************************//**
+* @brief Get relative time
+*//****************************************************************************/
+int32_t SysTimeGetRel (uint32_t tref) {
+   int32_t tdif = SysTickCnt - tref;
+   return tdif;
+}
+
+
 /* USER CODE END 0 */
 
 /* External variables --------------------------------------------------------*/
@@ -187,7 +204,7 @@ void SysTick_Handler(void)
   /* USER CODE END SysTick_IRQn 0 */
   HAL_IncTick();
   /* USER CODE BEGIN SysTick_IRQn 1 */
-
+  SysTickCnt++;
   /* USER CODE END SysTick_IRQn 1 */
 }