diff --git a/Core/Src/main.c b/Core/Src/main.c
index bc27da1..6cb5a4f 100644
--- a/Core/Src/main.c
+++ b/Core/Src/main.c
@@ -17,11 +17,13 @@
   */
 /* USER CODE END Header */
 /* Includes ------------------------------------------------------------------*/
+#include <usart2_it.h>
+#include <usart6_it.h>
 #include "main.h"
 
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
-
+#include "printf.h"
 /* USER CODE END Includes */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -59,6 +61,13 @@ static void MX_USART6_UART_Init(void);
 /* Private user code ---------------------------------------------------------*/
 /* USER CODE BEGIN 0 */
 
+/***************************************************************************//**
+* @brief Character send interface for printf function
+*//****************************************************************************/
+void uart_putc (void* p, char c) {
+   Usart6_PutByte(c);
+}
+
 /* USER CODE END 0 */
 
 /**
@@ -94,16 +103,31 @@ int main(void)
   MX_USART6_UART_Init();
   /* USER CODE BEGIN 2 */
 
+   Usart2_Init();
+   Usart6_Init();
+   init_printf(NULL, &uart_putc);   // connect printf to UART
+   printf("Hello world. This is a Nucleo UART and printf sample with IRQ and ring buffer.\n");
   /* USER CODE END 2 */
 
   /* Infinite loop */
   /* USER CODE BEGIN WHILE */
-  while (1)
-  {
-    /* USER CODE END WHILE */
+   while (1) {
+      int c;
 
-    /* USER CODE BEGIN 3 */
-  }
+      c = Usart2_GetByte();
+      if (c != -1) {                         // new incoming data
+         Usart6_PutByte(c);                  // UART2rx --> UART6tx
+      }
+
+      c = Usart6_GetByte();
+      if (c != -1) {                         // new incoming data
+         Usart2_PutByte(c);                  // UART6rx --> UART2tx
+      }
+
+      /* USER CODE END WHILE */
+
+      /* USER CODE BEGIN 3 */
+   }
   /* USER CODE END 3 */
 }