Revision 306:1f0269907d8b, committed 2014-08-29

Comitter:

mbed_official

Date:

Fri Aug 29 20:45:07 2014 +0100

Parent:

305:89b9c3a9a045

Child:

307:d33324c3b5a2

Commit message:

Synchronized with git revision f304c6ba83591678388024d30440e94781fa8d65

Full URL: https://github.com/mbedmicro/mbed/commit/f304c6ba83591678388024d30440e94781fa8d65/

[NUCLEOs] enhance i2c api

Changed in this revision

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F030R8/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F030R8/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -55,6 +55,9 @@
     {NC,    NC,    0}
 };
 
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+
 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
@@ -63,20 +66,28 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
         RCC_I2CCLKConfig(RCC_I2C1CLK_SYSCLK);
-    }
-    if (obj->i2c == I2C_2) {
-        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
     }
 
-    // Configure I2C pins
-    pinmap_pinout(scl, PinMap_I2C_SCL);
-    pin_mode(scl, OpenDrain);
-    pinmap_pinout(sda, PinMap_I2C_SDA);
-    pin_mode(sda, OpenDrain);
+    // Enable I2C2 clock and pinout if not done
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -90,6 +101,11 @@
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     I2C_InitTypeDef I2C_InitStructure;
     uint32_t tim = 0;
+    int timeout;
+	
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
 
     // Disable the Fast Mode Plus capability
     RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE); // Enable SYSCFG clock
@@ -260,6 +276,13 @@
 }
 
 void i2c_reset(i2c_t *obj) {
+    I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
+	
     if (obj->i2c == I2C_1) {
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F072RB/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F072RB/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -59,6 +59,9 @@
 
 I2C_HandleTypeDef I2cHandle;
 
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+
 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
@@ -67,20 +70,27 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         __HAL_RCC_I2C1_CONFIG(RCC_I2C1CLKSOURCE_SYSCLK);
         __I2C1_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
     }
-    if (obj->i2c == I2C_2) {
+    // Enable I2C2 clock and pinout if not done
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
         __I2C2_CLK_ENABLE();
-    }
-
     // Configure I2C pins
     pinmap_pinout(sda, PinMap_I2C_SDA);
     pinmap_pinout(scl, PinMap_I2C_SCL);
     pin_mode(sda, OpenDrain);
     pin_mode(scl, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -91,8 +101,12 @@
 
 void i2c_frequency(i2c_t *obj, int hz) {
     MBED_ASSERT((hz == 100000) || (hz == 400000) || (hz == 1000000));
+    I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
 
-    I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
 
     // Common settings: I2C clock = 48 MHz, Analog filter = ON, Digital filter coefficient = 0
     switch (hz) {
@@ -274,6 +288,12 @@
 }
 
 void i2c_reset(i2c_t *obj) {
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
+
     if (obj->i2c == I2C_1) {
         __I2C1_FORCE_RESET();
         __I2C1_RELEASE_RESET();

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F103RB/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F103RB/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -55,7 +55,13 @@
     {NC,    NC,    0}
 };
 
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+
 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
+    int timeout;
+    I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
+	
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
     I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
@@ -63,19 +69,25 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C clock and configure I2C pins if not done before
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
     }
-    if (obj->i2c == I2C_2) {
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
         RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
-    }
-
     // Configure I2C pins
     pinmap_pinout(scl, PinMap_I2C_SCL);
     pin_mode(scl, OpenDrain);
     pinmap_pinout(sda, PinMap_I2C_SDA);
     pin_mode(sda, OpenDrain);
+		}
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -85,10 +97,17 @@
 }
 
 void i2c_frequency(i2c_t *obj, int hz) {
+	  int timeout;
+	
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     I2C_InitTypeDef I2C_InitStructure;
 
     if ((hz != 0) && (hz <= 400000)) {
+			
+        // wait before init
+        timeout = LONG_TIMEOUT;
+        while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
+			
         I2C_DeInit(i2c);
 
         // I2C configuration
@@ -253,6 +272,13 @@
 }
 
 void i2c_reset(i2c_t *obj) {
+    I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
+	
     if (obj->i2c == I2C_1) {
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F302R8/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -63,6 +63,10 @@
     {NC,    NC,    0}
 };
 
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+int i2c3_inited = 0;
+
 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
@@ -71,23 +75,39 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
         RCC_I2CCLKConfig(RCC_I2C1CLK_SYSCLK);
-    }
-    if (obj->i2c == I2C_2) {
-        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
-    }
-    if (obj->i2c == I2C_3) {
-        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C3, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
     }
 
-    // Configure I2C pins
-    pinmap_pinout(scl, PinMap_I2C_SCL);
-    pin_mode(scl, OpenDrain);
-    pinmap_pinout(sda, PinMap_I2C_SDA);
-    pin_mode(sda, OpenDrain);
+    // Enable I2C2 clock and pinout if not done
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
+    }
+
+    // Enable I2C3 clock and pinout if not done
+    if ((obj->i2c == I2C_3)&& !i2c3_inited) {
+        i2c3_inited = 1;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C3, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -100,6 +120,11 @@
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     I2C_InitTypeDef I2C_InitStructure;
     uint32_t tim = 0;
+    int timeout;
+	
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
 
     // Disable the Fast Mode Plus capability
     RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE); // Enable SYSCFG clock
@@ -302,6 +327,13 @@
 }
 
 void i2c_reset(i2c_t *obj) {
+    I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
+	
     if (obj->i2c == I2C_1) {
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F334R8/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F334R8/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -57,8 +57,9 @@
 
 I2C_HandleTypeDef I2cHandle;
 
-void i2c_init(i2c_t *obj, PinName sda, PinName scl)
-{
+int i2c1_inited = 0;
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
     I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
@@ -66,17 +67,17 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    __I2C1_CLK_ENABLE();
-
-    // Configure the I2C clock source
-    __HAL_RCC_I2C1_CONFIG(RCC_I2C1CLKSOURCE_SYSCLK);
-  
-    // Configure I2C pins
-    pinmap_pinout(sda, PinMap_I2C_SDA);
-    pinmap_pinout(scl, PinMap_I2C_SCL);
-    pin_mode(sda, OpenDrain);
-    pin_mode(scl, OpenDrain);
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
+        __HAL_RCC_I2C1_CONFIG(RCC_I2C1CLKSOURCE_SYSCLK);
+        __I2C1_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -92,6 +93,11 @@
     MBED_ASSERT((hz == 100000) || (hz == 400000) || (hz == 1000000));
 
     I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
 
     // Update the SystemCoreClock variable.
     SystemCoreClockUpdate();
@@ -313,6 +319,12 @@
 
 void i2c_reset(i2c_t *obj)
 {
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
+
     __I2C1_FORCE_RESET();
     __I2C1_RELEASE_RESET();
 }

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F401RE/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F401RE/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -60,6 +60,10 @@
 
 I2C_HandleTypeDef I2cHandle;
 
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+int i2c3_inited = 0;
+
 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
@@ -68,22 +72,36 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         __I2C1_CLK_ENABLE();
-    }
-    if (obj->i2c == I2C_2) {
-        __I2C2_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
     }
-    if (obj->i2c == I2C_3) {
-        __I2C3_CLK_ENABLE();
+    // Enable I2C2 clock and pinout if not done
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
+        __I2C2_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
     }
-
-    // Configure I2C pins
-    pinmap_pinout(sda, PinMap_I2C_SDA);
-    pinmap_pinout(scl, PinMap_I2C_SCL);
-    pin_mode(sda, OpenDrain);
-    pin_mode(scl, OpenDrain);
+    // Enable I2C3 clock and pinout if not done
+    if ((obj->i2c == I2C_3)&& !i2c3_inited) {
+        i2c3_inited = 1;
+        __I2C3_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -98,6 +116,11 @@
 void i2c_frequency(i2c_t *obj, int hz) {
     MBED_ASSERT((hz != 0) && (hz <= 400000));
     I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+	
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
 
     // I2C configuration
     I2cHandle.Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
@@ -285,6 +308,12 @@
 }
 
 void i2c_reset(i2c_t *obj) {
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
+
     if (obj->i2c == I2C_1) {
         __I2C1_FORCE_RESET();
         __I2C1_RELEASE_RESET();

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F411RE/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F411RE/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -62,8 +62,11 @@
 
 I2C_HandleTypeDef I2cHandle;
 
-void i2c_init(i2c_t *obj, PinName sda, PinName scl)
-{
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+int i2c3_inited = 0;
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
     I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
@@ -71,22 +74,36 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         __I2C1_CLK_ENABLE();
-    }
-    if (obj->i2c == I2C_2) {
-        __I2C2_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
     }
-    if (obj->i2c == I2C_3) {
-        __I2C3_CLK_ENABLE();
+    // Enable I2C2 clock and pinout if not done
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
+        __I2C2_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
     }
-
-    // Configure I2C pins
-    pinmap_pinout(sda, PinMap_I2C_SDA);
-    pinmap_pinout(scl, PinMap_I2C_SCL);
-    pin_mode(sda, OpenDrain);
-    pin_mode(scl, OpenDrain);
+    // Enable I2C3 clock and pinout if not done
+    if ((obj->i2c == I2C_3)&& !i2c3_inited) {
+        i2c3_inited = 1;
+        __I2C3_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -98,10 +115,14 @@
     obj->slave = 0;
 }
 
-void i2c_frequency(i2c_t *obj, int hz)
-{
+void i2c_frequency(i2c_t *obj, int hz) {
     MBED_ASSERT((hz != 0) && (hz <= 400000));
     I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+	
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
 
     // I2C configuration
     I2cHandle.Init.AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
@@ -120,8 +141,7 @@
 
 }
 
-inline int i2c_start(i2c_t *obj)
-{
+inline int i2c_start(i2c_t *obj) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     int timeout;
 
@@ -144,8 +164,7 @@
     return 0;
 }
 
-inline int i2c_stop(i2c_t *obj)
-{
+inline int i2c_stop(i2c_t *obj) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
 
     // Generate the STOP condition
@@ -154,8 +173,7 @@
     return 0;
 }
 
-int i2c_read(i2c_t *obj, int address, char *data, int length, int stop)
-{
+int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
     int timeout;
@@ -205,8 +223,7 @@
     return length;
 }
 
-int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop)
-{
+int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
     int timeout;
@@ -251,8 +268,7 @@
     return count;
 }
 
-int i2c_byte_read(i2c_t *obj, int last)
-{
+int i2c_byte_read(i2c_t *obj, int last) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     int timeout;
 
@@ -275,8 +291,7 @@
     return (int)i2c->DR;
 }
 
-int i2c_byte_write(i2c_t *obj, int data)
-{
+int i2c_byte_write(i2c_t *obj, int data) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     int timeout;
 
@@ -294,8 +309,13 @@
     return 1;
 }
 
-void i2c_reset(i2c_t *obj)
-{
+void i2c_reset(i2c_t *obj) {
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
+
     if (obj->i2c == I2C_1) {
         __I2C1_FORCE_RESET();
         __I2C1_RELEASE_RESET();
@@ -312,8 +332,7 @@
 
 #if DEVICE_I2CSLAVE
 
-void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask)
-{
+void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     uint16_t tmpreg = 0;
 
@@ -327,8 +346,7 @@
     i2c->OAR1 = tmpreg;
 }
 
-void i2c_slave_mode(i2c_t *obj, int enable_slave)
-{
+void i2c_slave_mode(i2c_t *obj, int enable_slave) {
     I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
     if (enable_slave) {
         obj->slave = 1;
@@ -343,8 +361,7 @@
 #define WriteGeneral   2 // the master is writing to all slave
 #define WriteAddressed 3 // the master is writing to this slave (slave = receiver)
 
-int i2c_slave_receive(i2c_t *obj)
-{
+int i2c_slave_receive(i2c_t *obj) {
     int retValue = NoData;
 
     if (__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY) == 1) {
@@ -361,8 +378,7 @@
     return (retValue);
 }
 
-int i2c_slave_read(i2c_t *obj, char *data, int length)
-{
+int i2c_slave_read(i2c_t *obj, char *data, int length) {
     uint32_t Timeout;
     int size = 0;
 
@@ -416,8 +432,7 @@
     return size;
 }
 
-int i2c_slave_write(i2c_t *obj, const char *data, int length)
-{
+int i2c_slave_write(i2c_t *obj, const char *data, int length) {
     uint32_t Timeout;
     int size = 0;
 

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_L053R8/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_L053R8/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -60,6 +60,9 @@
 
 I2C_HandleTypeDef I2cHandle;
 
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+
 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
@@ -68,20 +71,27 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         __HAL_RCC_I2C1_CONFIG(RCC_I2C1CLKSOURCE_SYSCLK);
         __I2C1_CLK_ENABLE();
-    }
-    if (obj->i2c == I2C_2) {
-        __I2C2_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
     }
-
-    // Configure I2C pins
-    pinmap_pinout(sda, PinMap_I2C_SDA);
-    pinmap_pinout(scl, PinMap_I2C_SCL);
-    pin_mode(sda, OpenDrain);
-    pin_mode(scl, OpenDrain);
+    // Enable I2C2 clock and pinout if not done
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
+        __I2C2_CLK_ENABLE();
+        // Configure I2C pins
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(sda, OpenDrain);
+        pin_mode(scl, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -93,6 +103,11 @@
 void i2c_frequency(i2c_t *obj, int hz) {
     MBED_ASSERT((hz == 100000) || (hz == 400000) || (hz == 1000000));
     I2cHandle.Instance = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
 
     // Common settings: I2C clock = 32 MHz, Analog filter = ON, Digital filter coefficient = 0
     switch (hz) {
@@ -274,6 +289,12 @@
 }
 
 void i2c_reset(i2c_t *obj) {
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((__HAL_I2C_GET_FLAG(&I2cHandle, I2C_FLAG_BUSY)) && (timeout-- != 0));
+
     if (obj->i2c == I2C_1) {
         __I2C1_FORCE_RESET();
         __I2C1_RELEASE_RESET();

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_L152RE/i2c_api.c	Fri Aug 29 17:15:07 2014 +0100
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_L152RE/i2c_api.c	Fri Aug 29 20:45:07 2014 +0100
@@ -56,6 +56,9 @@
     {NC,    NC,    0}
 };
 
+int i2c1_inited = 0;
+int i2c2_inited = 0;
+
 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
     // Determine the I2C to use
     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
@@ -64,19 +67,27 @@
     obj->i2c = (I2CName)pinmap_merge(i2c_sda, i2c_scl);
     MBED_ASSERT(obj->i2c != (I2CName)NC);
 
-    // Enable I2C clock
-    if (obj->i2c == I2C_1) {
+    // Enable I2C1 clock and pinout if not done
+    if ((obj->i2c == I2C_1)&& !i2c1_inited) {
+        i2c1_inited = 1;
         RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
-    }
-    if (obj->i2c == I2C_2) {
-        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
     }
 
-    // Configure I2C pins
-    pinmap_pinout(scl, PinMap_I2C_SCL);
-    pin_mode(scl, OpenDrain);
-    pinmap_pinout(sda, PinMap_I2C_SDA);
-    pin_mode(sda, OpenDrain);
+    // Enable I2C2 clock and pinout if not done
+    if ((obj->i2c == I2C_2)&& !i2c2_inited) {
+        i2c2_inited = 1;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
+        // Configure I2C pins
+        pinmap_pinout(scl, PinMap_I2C_SCL);
+        pin_mode(scl, OpenDrain);
+        pinmap_pinout(sda, PinMap_I2C_SDA);
+        pin_mode(sda, OpenDrain);
+    }
 
     // Reset to clear pending flags if any
     i2c_reset(obj);
@@ -88,10 +99,15 @@
 void i2c_frequency(i2c_t *obj, int hz) {
     I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
     I2C_InitTypeDef I2C_InitStructure;
+    int timeout;
 
     if (hz == 0) return;
     if (hz > 400000) hz = 400000;
 
+    // wait before init
+    timeout = LONG_TIMEOUT;
+    while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
+
     /* Warning: To use the I2C at 400 kHz (in fast mode), the PCLK1 frequency
       (I2C peripheral input clock) must be a multiple of 10 MHz.
       With the actual clock configuration, the max frequency is measured at 296 kHz */
@@ -272,6 +288,13 @@
 }
 
 void i2c_reset(i2c_t *obj) {
+    I2C_TypeDef *i2c = (I2C_TypeDef *)(obj->i2c);
+    int timeout;
+	
+    // wait before reset
+    timeout = LONG_TIMEOUT;
+    while((I2C_GetFlagStatus(i2c, I2C_FLAG_BUSY)) && (timeout-- != 0));
+	
     if (obj->i2c == I2C_1) {
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
         RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);