Add Serial_IsSendReady() and Serial_IsSendComplete() serial driver API functions.

[pub/lufa.git] / LUFA / Drivers / Peripheral / XMEGA / Serial_XMEGA.h

diff --git a/LUFA/Drivers/Peripheral/XMEGA/Serial_XMEGA.h b/LUFA/Drivers/Peripheral/XMEGA/Serial_XMEGA.h
index 1161ef6..e7f9fee 100644 (file)
--- a/LUFA/Drivers/Peripheral/XMEGA/Serial_XMEGA.h
+++ b/LUFA/Drivers/Peripheral/XMEGA/Serial_XMEGA.h
@@ -216,8 +216,37 @@
                                return ((USART->STATUS & USART_RXCIF_bm) ? true : false);
                        }
 
+                       /** Indicates whether there is hardware buffer space for a new transmit on the USART. This
+                        *  function can be used to determine if a call to \ref Serial_SendByte() will block in advance.
+                        *
+                        *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
+                        *
+                        *  \return Boolean \c true if a character can be queued for transmission immediately, \c false otherwise.
+                        */
+                       static inline bool Serial_IsSendReady(USART_t* const USART) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
+                       static inline bool Serial_IsSendReady(USART_t* const USART)
+                       {
+                               return (USART->STATUS & USART_DREIF_bm) ? true : false);
+                       }
+
+                       /** Indicates whether the hardware USART transmit buffer is completely empty, indicating all
+                        *  pending transmissions have completed.
+                        *
+                        *  \param[in,out] USART  Pointer to the base of the USART peripheral within the device.
+                        *
+                        *  \return Boolean \c true if no characters are buffered for transmission, \c false otherwise.
+                        */
+                       static inline bool Serial_IsSendComplete(USART_t* const USART) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT ATTR_NON_NULL_PTR_ARG(1);
+                       static inline bool Serial_IsSendComplete(USART_t* const USART)
+                       {
+                               return (USART->STATUS & USART_TCXIF_bm) ? true : false);
+                       }
+
                        /** Transmits a given byte through the USART.
                         *
+                        *  \note If no buffer space is available in the hardware USART, this function will block. To check if
+                        *        space is available before calling this function, see \ref Serial_IsSendReady().
+                        *
                         *  \param[in,out] USART     Pointer to the base of the USART peripheral within the device.
                         *  \param[in]     DataByte  Byte to transmit through the USART.
                         */
@@ -226,7 +255,7 @@
                        static inline void Serial_SendByte(USART_t* const USART,
                                                           const char DataByte)
                        {
-                               while (!(USART->STATUS & USART_DREIF_bm));
+                               while (!(Serial_IsSendReady(USART));
                                USART->DATA = DataByte;
                        }