diff --git a/Core/Src/main.c b/Core/Src/main.c
index 23b2d7b..ae73954 100644
--- a/Core/Src/main.c
+++ b/Core/Src/main.c
@@ -77,11 +77,16 @@ static void MX_SDIO_SD_Init(void);
 static void MX_USART1_UART_Init(void);
 
 /* USER CODE BEGIN PFP */
-int _write(int file, char *ptr, int len) {
- for (int i = 0; i < len; i++) {
- ITM_SendChar((*ptr++));
- }
- return len;
+int _write(int file, char *ptr, int len)
+{
+  if ((CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA_Msk) && (ITM->TCR & ITM_TCR_ITMENA_Msk))
+  {
+    for (int i = 0; i < len; i++)
+    {
+      ITM_SendChar((*ptr++));
+    }
+  }
+  return len;
 }
 /* USER CODE END PFP */