      }
  
    /* Loop until the transfer is complete. */
+@@ -737,6 +737,10 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
+   start = clock_systimer();
+   do
+     {
++      /* Calculate the elapsed time */
++
++      elapsed = clock_systimer() - start;
++
+       /* Check for STOP condition */
+ 
+       cr1 = stm32_i2c_getreg(priv, STM32_I2C_CR1_OFFSET);
+@@ -753,9 +757,6 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
+           return;
+         }
+ 
+-      /* Calculate the elapsed time */
+-
+-      elapsed = clock_systimer() - start;
+     }
+ 
+   /* Loop until the stop is complete or a timeout occurs. */
 diff --git NuttX/nuttx/arch/arm/src/stm32/stm32f30xxx_i2c.c NuttX/nuttx/arch/arm/src/stm32/stm32f30xxx_i2c.c
-index 312e0b4..193ccb8 100644
+index 312e0b4..b2da861 100644
 --- NuttX/nuttx/arch/arm/src/stm32/stm32f30xxx_i2c.c
 +++ NuttX/nuttx/arch/arm/src/stm32/stm32f30xxx_i2c.c
 @@ -7,7 +7,7 @@

     }
 
   /* Loop until the transfer is complete. */

     }
 
   /* Loop until the transfer is complete. */
@@ -731,6 +731,10 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
   start = clock_systimer();
   do
     {
+      /* Calculate the elapsed time */
+
+      elapsed = clock_systimer() - start;
+
       /* Check for STOP condition */
 
       cr1 = stm32_i2c_getreg(priv, STM32_I2C_CR1_OFFSET);
@@ -747,9 +751,6 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
           return;
         }
 
-      /* Calculate the elapsed time */
-
-      elapsed = clock_systimer() - start;
     }
 
   /* Loop until the stop is complete or a timeout occurs. */
diff --git NuttX/nuttx/arch/arm/src/stm32f7/stm32_i2c.c NuttX/nuttx/arch/arm/src/stm32f7/stm32_i2c.c
index d089db9..fd73457 100644
--- NuttX/nuttx/arch/arm/src/stm32f7/stm32_i2c.c
+++ NuttX/nuttx/arch/arm/src/stm32f7/stm32_i2c.c
@@ -7,7 +7,7 @@
  *
  * With extensions and modifications for the F1, F2, and F4 by:
  *
- *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2016-2017 Gregory Nutt. All rights reserved.
  *   Authors: Gregroy Nutt <gnutt@nuttx.org>
  *            John Wharington
  *            David Sidrane <david_s5@nscdg.com>
@@ -897,15 +897,15 @@ static inline int stm32_i2c_sem_waitdone(FAR struct stm32_i2c_priv_s *priv)
 
   do
