diff --git a/STM32F1/system/libmaple/include/libmaple/delay.h b/STM32F1/system/libmaple/include/libmaple/delay.h
index 472a208..64bb510 100644
--- a/STM32F1/system/libmaple/include/libmaple/delay.h
+++ b/STM32F1/system/libmaple/include/libmaple/delay.h
@@ -46,6 +46,10 @@ extern "C" {
  * @param us Number of microseconds to delay.
  */
 static inline void delay_us(uint32 us) {
+	if (us==0)
+	{
+		return;
+	}
     us *= STM32_DELAY_US_MULT;
 
     /* fudge for function call overhead  */