STM32: serial: clear Overrun flag if it is set when checking if readable

Note that this could have side effects on the application as it would
not be aware that data has been missed. This may be later solved by
adding an error management parameter to the Serial API in mbed.

The advantage is that the serial link can work again.

targets/TARGET_STM/TARGET_STM32F0/serial_device.c

@@ -472,7 +472,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32F1/serial_device.c

@@ -289,7 +289,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32F2/serial_device.c

@@ -438,7 +438,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32F3/serial_device.c

@@ -373,7 +373,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32F4/serial_device.c

@@ -435,7 +435,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32F7/serial_device.c

@@ -426,7 +426,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32L0/serial_device.c

@@ -355,7 +355,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32L1/serial_device.c

@@ -345,7 +345,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }

targets/TARGET_STM/TARGET_STM32L4/serial_device.c

@@ -391,7 +391,12 @@ int serial_readable(serial_t *obj)
 {
     struct serial_s *obj_s = SERIAL_S(obj);
     UART_HandleTypeDef *huart = &uart_handlers[obj_s->index];
-    
+    /*  To avoid a target blocking case, let's check for
+     *  possible OVERRUN error and discard it
+     */
+    if(__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE)) {
+        __HAL_UART_CLEAR_OREFLAG(huart);
+    }
     // Check if data is received
     return (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) ? 1 : 0;
 }