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

[pub/lufa.git] / LUFA / Drivers / Peripheral / AVR8 / Serial_AVR8.h

diff --git a/LUFA/Drivers/Peripheral/AVR8/Serial_AVR8.h b/LUFA/Drivers/Peripheral/AVR8/Serial_AVR8.h
index f951f6b..e8860a5 100644 (file)
--- a/LUFA/Drivers/Peripheral/AVR8/Serial_AVR8.h
+++ b/LUFA/Drivers/Peripheral/AVR8/Serial_AVR8.h
@@ -210,14 +210,39 @@
                                return ((UCSR1A & (1 << RXC1)) ? 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.
+                        *
+                        *  \return Boolean \c true if a character can be queued for transmission immediately, \c false otherwise.
+                        */
+                       static inline bool Serial_IsSendReady(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
+                       static inline bool Serial_IsSendReady(void)
+                       {
+                               return ((UCSR1A & (1 << UDRE1)) ? true : false);
+                       }
+
+                       /** Indicates whether the hardware USART transmit buffer is completely empty, indicating all
+                        *  pending transmissions have completed.
+                        *
+                        *  \return Boolean \c true if no characters are buffered for transmission, \c false otherwise.
+                        */
+                       static inline bool Serial_IsSendComplete(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
+                       static inline bool Serial_IsSendComplete(void)
+                       {
+                               return ((UCSR1A & (1 << TXC1)) ? 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] DataByte  Byte to transmit through the USART.
                         */
                        static inline void Serial_SendByte(const char DataByte) ATTR_ALWAYS_INLINE;
                        static inline void Serial_SendByte(const char DataByte)
                        {
-                               while (!(UCSR1A & (1 << UDRE1)));
+                               while (!(Serial_IsSendReady()));
                                UDR1 = DataByte;
                        }