diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F0/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F0/serial_api.c
index afd98f83b33..8f0472ac891 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F0/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F0/serial_api.c
@@ -459,6 +459,15 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
  * READ/WRITE
  ******************************************************************************/
 
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UartHandle.Instance = (USART_TypeDef *)(obj->uart);
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
+
 int serial_getc(serial_t *obj) {
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
     while (!serial_readable(obj));
@@ -469,6 +478,7 @@ void serial_putc(serial_t *obj, int c) {
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
     while (!serial_writable(obj));
     uart->TDR = (uint32_t)(c & (uint16_t)0xFF);
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj) {
@@ -482,7 +492,7 @@ int serial_readable(serial_t *obj) {
 int serial_writable(serial_t *obj) {
     int status;
     UartHandle.Instance = (USART_TypeDef *)(obj->uart);
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F1/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F1/serial_api.c
index dffaf315a47..fe542450729 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F1/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F1/serial_api.c
@@ -287,6 +287,14 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
 /******************************************************************************
  * READ/WRITE
  ******************************************************************************/
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UartHandle.Instance = (USART_TypeDef *)(obj->uart);
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
 
 int serial_getc(serial_t *obj)
 {
@@ -308,6 +316,7 @@ void serial_putc(serial_t *obj, int c)
     } else {
         uart->DR = (uint16_t)(c & (uint16_t)0x1FF);
     }
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj)
@@ -323,7 +332,7 @@ int serial_writable(serial_t *obj)
 {
     int status;
     UartHandle.Instance = (USART_TypeDef *)(obj->uart);
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F3/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F3/serial_api.c
index a035b33ad05..ba96f58466c 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F3/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F3/serial_api.c
@@ -351,6 +351,15 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
  * READ/WRITE
  ******************************************************************************/
 
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UartHandle.Instance = (USART_TypeDef *)(obj->uart);
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
+
 int serial_getc(serial_t *obj)
 {
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
@@ -371,6 +380,7 @@ void serial_putc(serial_t *obj, int c)
     } else {
         uart->TDR = (uint16_t)(c & (uint16_t)0x1FF);
     }
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj)
@@ -386,7 +396,7 @@ int serial_writable(serial_t *obj)
 {
     int status;
     UartHandle.Instance = (USART_TypeDef *)(obj->uart);
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F4/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F4/serial_api.c
index 27361731aaf..9c1a596e789 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F4/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F4/serial_api.c
@@ -807,6 +807,15 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
  * READ/WRITE
  ******************************************************************************/
 
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UART_HandleTypeDef *handle = &UartHandle[SERIAL_OBJ(index)];
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(handle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
+
 int serial_getc(serial_t *obj)
 {
     UART_HandleTypeDef *handle = &UartHandle[SERIAL_OBJ(index)];
@@ -819,6 +828,7 @@ void serial_putc(serial_t *obj, int c)
     UART_HandleTypeDef *handle = &UartHandle[SERIAL_OBJ(index)];
     while (!serial_writable(obj));
     handle->Instance->DR = (uint32_t)(c & 0x1FF);
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj)
@@ -834,7 +844,7 @@ int serial_writable(serial_t *obj)
 {
     int status;
     UART_HandleTypeDef *handle = &UartHandle[SERIAL_OBJ(index)];
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(handle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F7/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F7/serial_api.c
index b0468ac5d10..fa16a2fc374 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F7/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F7/serial_api.c
@@ -417,6 +417,15 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
  * READ/WRITE
  ******************************************************************************/
 
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UartHandle.Instance = (USART_TypeDef *)(obj->uart);
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
+
 int serial_getc(serial_t *obj)
 {
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
@@ -429,6 +438,7 @@ void serial_putc(serial_t *obj, int c)
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
     while (!serial_writable(obj));
     uart->TDR = (uint32_t)(c & 0x1FF);
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj)
@@ -444,7 +454,7 @@ int serial_writable(serial_t *obj)
 {
     int status;
     UartHandle.Instance = (USART_TypeDef *)(obj->uart);
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32L0/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32L0/serial_api.c
index 5d61d99e82c..1332dc68d30 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32L0/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32L0/serial_api.c
@@ -360,6 +360,15 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
  * READ/WRITE
  ******************************************************************************/
 
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UartHandle.Instance = (USART_TypeDef *)(obj->uart);
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
+
 int serial_getc(serial_t *obj)
 {
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
@@ -372,6 +381,7 @@ void serial_putc(serial_t *obj, int c)
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
     while (!serial_writable(obj));
     uart->TDR = (uint32_t)(c & (uint32_t)0xFF);
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj)
@@ -387,7 +397,7 @@ int serial_writable(serial_t *obj)
 {
     int status;
     UartHandle.Instance = (USART_TypeDef *)(obj->uart);
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32L1/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32L1/serial_api.c
index 434bd4344d5..2730c85f337 100755
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32L1/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32L1/serial_api.c
@@ -355,6 +355,15 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
  * READ/WRITE
  ******************************************************************************/
 
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UartHandle.Instance = (USART_TypeDef *)(obj->uart);
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
+
 int serial_getc(serial_t *obj)
 {
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
@@ -367,6 +376,7 @@ void serial_putc(serial_t *obj, int c)
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
     while (!serial_writable(obj));
     uart->DR = (uint32_t)(c & 0xFF);
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj)
@@ -382,7 +392,7 @@ int serial_writable(serial_t *obj)
 {
     int status;
     UartHandle.Instance = (USART_TypeDef *)(obj->uart);
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32L4/serial_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32L4/serial_api.c
index 0bf46092c42..bc46fef6e0a 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32L4/serial_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32L4/serial_api.c
@@ -423,6 +423,15 @@ void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
  * READ/WRITE
  ******************************************************************************/
 
+int serial_TxComplete(serial_t *obj)
+{
+    int status;
+    UartHandle.Instance = (USART_TypeDef *)(obj->uart);
+    // Check if data is transmitted
+    status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TC) != RESET) ? 1 : 0);
+    return status;
+}
+
 int serial_getc(serial_t *obj)
 {
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
@@ -435,6 +444,7 @@ void serial_putc(serial_t *obj, int c)
     USART_TypeDef *uart = (USART_TypeDef *)(obj->uart);
     while (!serial_writable(obj));
     uart->TDR = (uint32_t)(c & (uint32_t)0xFF);
+    while(!serial_TxComplete(obj));
 }
 
 int serial_readable(serial_t *obj)
@@ -450,7 +460,7 @@ int serial_writable(serial_t *obj)
 {
     int status;
     UartHandle.Instance = (USART_TypeDef *)(obj->uart);
-    // Check if data is transmitted
+    // Check if data has moved to internal buffer
     status = ((__HAL_UART_GET_FLAG(&UartHandle, UART_FLAG_TXE) != RESET) ? 1 : 0);
     return status;
 }