From 9b204f8be20d686a61ceda81dba186def7b471cf Mon Sep 17 00:00:00 2001
From: Erwan GOURIOU <frq07517@st.com>
Date: Thu, 1 Sep 2016 17:25:45 +0200
Subject: [PATCH] Fix I2C byte transfer API to enable Master/Slave test on
 F411RE

i2c_byte_write could be used to send byte and address.
In case used for address, ADDR Flag should be reset.
---
 .../hal/TARGET_STM/TARGET_STM32F4/i2c_api.c   | 21 +++++++++++++++++--
 .../tests/mbed/i2c_master_slave/main.cpp      |  4 ++++
 tools/tests.py                                |  3 ++-
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F4/i2c_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F4/i2c_api.c
index 0efae0421a..dc5f6cc4d5 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F4/i2c_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F4/i2c_api.c
@@ -213,8 +213,19 @@ inline int i2c_start(i2c_t *obj) {
 
 inline int i2c_stop(i2c_t *obj) {
 
+    int timeout;
     struct i2c_s *obj_s = I2C_S(obj);
     I2C_TypeDef *i2c = (I2C_TypeDef *)obj_s->i2c;
+    I2C_HandleTypeDef *handle = &(obj_s->handle);
+
+    //Wait Byte transfer finished before sending stop
+    timeout = FLAG_TIMEOUT;
+    while (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_BTF) == RESET) {
+        timeout--;
+        if (timeout == 0) {
+            return 0;
+        }
+    }
 
     // Generate the STOP condition
     i2c->CR1 |= I2C_CR1_STOP;
@@ -350,15 +361,21 @@ int i2c_byte_write(i2c_t *obj, int data) {
 
     handle->Instance->DR = (uint8_t)data;
 
-    // Wait until the byte is transmitted
+    // Wait until the byte (might be the adress) is transmitted
     timeout = FLAG_TIMEOUT;
     while ((__HAL_I2C_GET_FLAG(handle, I2C_FLAG_TXE) == RESET) &&
-            (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_BTF) == RESET)) {
+            (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_BTF) == RESET) &&
+             (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_ADDR) == RESET)) {
         if ((timeout--) == 0) {
             return 0;
         }
     }
 
+     if (__HAL_I2C_GET_FLAG(handle, I2C_FLAG_ADDR) != RESET)
+     {
+         __HAL_I2C_CLEAR_ADDRFLAG(handle);
+     }
+
     return 1;
 }
 
diff --git a/libraries/tests/mbed/i2c_master_slave/main.cpp b/libraries/tests/mbed/i2c_master_slave/main.cpp
index 76fdb1a337..10b1e82117 100644
--- a/libraries/tests/mbed/i2c_master_slave/main.cpp
+++ b/libraries/tests/mbed/i2c_master_slave/main.cpp
@@ -16,6 +16,10 @@
 //   pull-up resistors on both lines
 // ********************************************************
 
+#if defined(TARGET_NUCLEO_F411RE)
+I2C master(PB_9, PB_8); // I2C_1 (Arduino: D14/D15)
+I2CSlave slave(PB_3, PB_10); // I2C_2 (Arduino: D3/D6)
+#endif
 
 int main()
 {
diff --git a/tools/tests.py b/tools/tests.py
index 67570fe868..b93661c3eb 100644
--- a/tools/tests.py
+++ b/tools/tests.py
@@ -87,6 +87,7 @@ Wiring:
 
   * i2c_loop:
       * LPC1768: (p28 <-> p9), (p27 <-> p10)
+      * NUCLEO_F411RE: (PB_9 <-> PB_3), (PB_8 <-> PB_10)
 
   * i2c_eeprom:
       * LPC1*: (SDA=p28 , SCL=p27)
@@ -264,7 +265,7 @@ TESTS = [
         "id": "MBED_A20", "description": "I2C master/slave test",
         "source_dir": join(TEST_DIR, "mbed", "i2c_master_slave"),
         "dependencies": [MBED_LIBRARIES, TEST_MBED_LIB,],
-        "mcu": ["LPC1768", "RZ_A1H"],
+        "mcu": ["LPC1768", "RZ_A1H", "NUCLEO_F411RE"],
         "peripherals": ["i2c_loop"]
     },
     {