Added PRNT_Host_SendByte() and PRNT_Host_Flush() functions to the Host mode Printer Class driver.

Modified PRNT_Host_USBTask() to flush the output pipe on each call.

LUFA/Drivers/USB/Class/Host/Printer.c

@@ -125,6 +125,11 @@ static uint8_t DCOMP_PRNT_NextPRNTInterfaceEndpoint(void* CurrentDescriptor)
 	return DESCRIPTOR_SEARCH_NotFound;
 }
 
+void PRNT_Host_USBTask(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo)
+{
+	PRNT_Host_Flush(PRNTInterfaceInfo);
+}
+
 uint8_t PRNT_Host_SetBidirectionalMode(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo)
 {
 	if (PRNTInterfaceInfo->State.AlternateSetting)
@@ -182,6 +187,61 @@ uint8_t PRNT_Host_SoftReset(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo)
 	return USB_Host_SendControlRequest(NULL);
 }
 
+uint8_t PRNT_Host_Flush(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo)
+{
+	if ((USB_HostState != HOST_STATE_Configured) || !(PRNTInterfaceInfo->State.IsActive))
+	  return PIPE_READYWAIT_DeviceDisconnected;
+	  
+	uint8_t ErrorCode;
+
+	Pipe_SelectPipe(PRNTInterfaceInfo->Config.DataOUTPipeNumber);	
+	Pipe_Unfreeze();
+	
+	if (!(Pipe_BytesInPipe()))
+	  return PIPE_READYWAIT_NoError;
+
+	bool BankFull = !(Pipe_IsReadWriteAllowed());
+
+	Pipe_ClearOUT();
+
+	if (BankFull)
+	{
+		if ((ErrorCode = Pipe_WaitUntilReady()) != PIPE_READYWAIT_NoError)
+		  return ErrorCode;
+
+		Pipe_ClearOUT();
+	}
+
+	Pipe_Freeze();
+	
+	return PIPE_READYWAIT_NoError;
+}
+
+uint8_t PRNT_Host_SendByte(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo,
+                           const uint8_t Data)
+{
+	if ((USB_HostState != HOST_STATE_Configured) || !(PRNTInterfaceInfo->State.IsActive))
+	  return PIPE_READYWAIT_DeviceDisconnected;
+	  
+	uint8_t ErrorCode;
+
+	Pipe_SelectPipe(PRNTInterfaceInfo->Config.DataOUTPipeNumber);	
+	Pipe_Unfreeze();
+	
+	if (!(Pipe_IsReadWriteAllowed()))
+	{
+		Pipe_ClearOUT();
+
+		if ((ErrorCode = Pipe_WaitUntilReady()) != PIPE_READYWAIT_NoError)
+		  return ErrorCode;
+	}
+
+	Pipe_Write_Byte(Data);	
+	Pipe_Freeze();
+	
+	return PIPE_READYWAIT_NoError;
+}
+
 uint8_t PRNT_Host_SendString(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo,
                              void* Buffer,
                              const uint16_t Length)

LUFA/Drivers/USB/Class/Host/Printer.h

@@ -114,6 +114,14 @@
 			};
 	
 		/* Function Prototypes: */
+			/** General management task for a given Printer host class interface, required for the correct operation of
+			 *  the interface. This should be called frequently in the main program loop, before the master USB management task
+			 *  \ref USB_USBTask().
+			 *
+			 *  \param[in,out] PRNTInterfaceInfo  Pointer to a structure containing a Printer Class host configuration and state.
+			 */
+			void PRNT_Host_USBTask(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1);
+
 			/** Host interface configuration routine, to configure a given Printer host interface instance using the
 			 *  Configuration Descriptor read from an attached USB device. This function automatically updates the given Printer
 			 *  instance's state values and configures the pipes required to communicate with the interface if it is found within
@@ -159,6 +167,17 @@
 			 */
 			uint8_t PRNT_Host_SoftReset(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1);
 
+			/** Flushes any data waiting to be sent, ensuring that the send buffer is cleared.
+			 *
+			 *  \pre This function must only be called when the Host state machine is in the HOST_STATE_Configured state or the
+			 *       call will fail.
+			 *
+			 *  \param[in,out] PRNTInterfaceInfo  Pointer to a structure containing a Printer Class host configuration and state.
+			 *
+			 *  \return A value from the \ref Pipe_WaitUntilReady_ErrorCodes_t enum.
+			 */
+			uint8_t PRNT_Host_Flush(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1);
+
 			/** Sends the given raw data stream to the attached printer's input endpoint. This should contain commands that the
 			 *  printer is able to understand - for example, PCL data. Not all printers accept all printer languages; see
 			 *  \ref PRNT_Host_GetDeviceID() for details on determining acceptable languages for an attached printer.
@@ -176,6 +195,22 @@
 			                             void* Buffer, 
 			                             const uint16_t Length) ATTR_NON_NULL_PTR_ARG(1) ATTR_NON_NULL_PTR_ARG(2);
 
+			/** Sends a given byte to the attached USB device, if connected. If a device is not connected when the function is called, the
+			 *  byte is discarded. Bytes will be queued for transmission to the device until either the pipe bank becomes full, or the
+			 *  \ref PRNT_Host_Flush() function is called to flush the pending data to the host. This allows for multiple bytes to be 
+			 *  packed into a single pipe packet, increasing data throughput.
+			 *
+			 *  \pre This function must only be called when the Host state machine is in the HOST_STATE_Configured state or the
+			 *       call will fail.
+			 *
+			 *  \param[in,out] PRNTInterfaceInfo  Pointer to a structure containing a Printer Class host configuration and state.
+			 *  \param[in]     Data               Byte of data to send to the device.
+			 *
+			 *  \return A value from the \ref Pipe_WaitUntilReady_ErrorCodes_t enum.
+			 */
+			uint8_t PRNT_Host_SendByte(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo,
+			                           const uint8_t Data) ATTR_NON_NULL_PTR_ARG(1);
+
 			/** Determines the number of bytes received by the printer interface from the device, waiting to be read. This indicates the number
 			 *  of bytes in the IN pipe bank only, and thus the number of calls to \ref PRNT_Host_ReceiveByte() which are guaranteed to succeed
 			 *  immediately. If multiple bytes are to be received, they should be buffered by the user application, as the pipe bank will not be
@@ -220,19 +255,6 @@
 			                              char* const DeviceIDString,
 			                              const uint16_t BufferSize) ATTR_NON_NULL_PTR_ARG(1) ATTR_NON_NULL_PTR_ARG(2);
 
-		/* Inline Functions: */
-			/** General management task for a given Printer host class interface, required for the correct operation of
-			 *  the interface. This should be called frequently in the main program loop, before the master USB management task
-			 *  \ref USB_USBTask().
-			 *
-			 *  \param[in,out] PRNTInterfaceInfo  Pointer to a structure containing a Printer Class host configuration and state.
-			 */
-			static inline void PRNT_Host_USBTask(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1);
-			static inline void PRNT_Host_USBTask(USB_ClassInfo_PRNT_Host_t* const PRNTInterfaceInfo)
-			{
-				(void)PRNTInterfaceInfo;
-			}
-
 	/* Private Interface - For use in library only: */
 	#if !defined(__DOXYGEN__)
 		/* Macros: */

LUFA/ManPages/ChangeLog.txt

@@ -16,7 +16,8 @@
   *  - Added new USB_Device_GetFrameNumber() and USB_Host_GetFrameNumber() functions to retrieve the current USB frame number
   *  - Added new USB_Host_EnableSOFEvents(), USB_Host_DisableSOFEvents() and EVENT_USB_Host_StartOfFrame() for the user application
   *    handling of USB Start of Frame events while in USB Host mode
-  *  - Added new PRNT_Host_BytesReceived() and PRNT_Host_ReceiveByte() functions to the Print Host Class driver
+  *  - Added new PRNT_Host_BytesReceived(), PRNT_Host_ReceiveByte(), PRNT_Host_SendByte() and PRNT_Host_Flush() functions to the
+  *    Print Host Class driver
   *  - Added class specific descriptor type defines with standard USB-IF element naming
   *  - Added new project makefile template to the library and moved board driver stub files into in a new "CodeTemplates" directory
   *