X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/cb779e3d7d32d7c43e0a45bb526de0a04135b0c7..ec537fd84d6ad3fd0dfa1b55efa2c2d554c1db48:/Projects/XPLAINBridge/XPLAINBridge.c?ds=sidebyside

diff --git a/Projects/XPLAINBridge/XPLAINBridge.c b/Projects/XPLAINBridge/XPLAINBridge.c
index 8cd1b2dd2..912e68367 100644
--- a/Projects/XPLAINBridge/XPLAINBridge.c
+++ b/Projects/XPLAINBridge/XPLAINBridge.c
@@ -31,7 +31,7 @@
 /** \file
  *
  *  Main source file for the XPLAINBridge project. This file contains the main tasks of
- *  the demo and is responsible for the initial application hardware configuration.
+ *  the project and is responsible for the initial application hardware configuration.
  */
 
 #include "XPLAINBridge.h"
@@ -119,20 +119,36 @@ void UARTBridge_Task(void)
 	if (USB_DeviceState != DEVICE_STATE_Configured)
 	  return;
 
-	/* Read bytes from the USB OUT endpoint into the UART transmit buffer */
-	int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
-	if (!(ReceivedByte < 0) && !(RingBuffer_IsFull(&USBtoUART_Buffer)))
-	  RingBuffer_Insert(&USBtoUART_Buffer, ReceivedByte);
+	/* Only try to read in bytes from the CDC interface if the transmit buffer is not full */
+	if (!(RingBuffer_IsFull(&USBtoUART_Buffer)))
+	{
+		int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
 
+		/* Read bytes from the USB OUT endpoint into the UART transmit buffer */
+		if (!(ReceivedByte < 0))
+		  RingBuffer_Insert(&USBtoUART_Buffer, ReceivedByte);
+	}
+	
 	/* Check if the UART receive buffer flush timer has expired or buffer is nearly full */
 	RingBuff_Count_t BufferCount = RingBuffer_GetCount(&UARTtoUSB_Buffer);
 	if ((TIFR0 & (1 << TOV0)) || (BufferCount > 200))
 	{
+		/* Clear flush timer expiry flag */
 		TIFR0 |= (1 << TOV0);
 
-		/* Read bytes from the UART receive buffer into the USB IN endpoint */
+		/* Read bytes from the USART receive buffer into the USB IN endpoint */
 		while (BufferCount--)
-		  CDC_Device_SendByte(&VirtualSerial_CDC_Interface, RingBuffer_Remove(&UARTtoUSB_Buffer));
+		{
+			/* Try to send the next byte of data to the host, abort if there is an error without dequeuing */
+			if (CDC_Device_SendByte(&VirtualSerial_CDC_Interface,
+									RingBuffer_Peek(&UARTtoUSB_Buffer)) != ENDPOINT_READYWAIT_NoError)
+			{
+				break;
+			}
+
+			/* Dequeue the already sent byte from the buffer now we have confirmed that no transmission error occurred */
+			RingBuffer_Remove(&UARTtoUSB_Buffer);
+		}
 	}
 
 	CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
@@ -206,8 +222,8 @@ void EVENT_USB_Device_ConfigurationChanged(void)
 	LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 }
 
-/** Event handler for the library USB Unhandled Control Request event. */
-void EVENT_USB_Device_UnhandledControlRequest(void)
+/** Event handler for the library USB Control Request reception event. */
+void EVENT_USB_Device_ControlRequest(void)
 {
 	if (CurrentFirmwareMode == MODE_USART_BRIDGE)
 	  CDC_Device_ProcessControlRequest(&VirtualSerial_CDC_Interface);