Fixed possible lost data in the XPLAINBridge, USBtoSerial and Benito projects when the host exceeds the packet timeout period on received packets as set by USB_STREAM_TIMEOUT_MS (thanks to Justin Rajewski).

3 files changed, 39 insertions, 9 deletions

diff --git a/Projects/Benito/Benito.c b/Projects/Benito/Benito.c
index fbb81840f..c6cbf02b3 100644
--- a/Projects/Benito/Benito.c
+++ b/Projects/Benito/Benito.c
@@ -37,7 +37,7 @@
 #include "Benito.h"
 
 /** Circular buffer to hold data from the serial port before it is sent to the host. */
-RingBuff_t Tx_Buffer;
+RingBuff_t USARTtoUSB_Buffer;
 
 /** Pulse generation counters to keep track of the number of milliseconds remaining for each pulse type */
 volatile struct
@@ -85,7 +85,7 @@ int main(void)
 {
 	SetupHardware();
 
-	RingBuffer_InitBuffer(&Tx_Buffer);
+	RingBuffer_InitBuffer(&USARTtoUSB_Buffer);
 
 	sei();
 
@@ -126,15 +126,25 @@ int main(void)
 			  LEDs_TurnOffLEDs(LEDMASK_RX);
 
 			/* Check if the receive buffer flush period has expired */
-			RingBuff_Count_t BufferCount = RingBuffer_GetCount(&Tx_Buffer);
+			RingBuff_Count_t BufferCount = RingBuffer_GetCount(&USARTtoUSB_Buffer);
 			if (!(--FlushPeriodRemaining) || (BufferCount > 200))
 			{
 				/* Echo bytes from the target to the host via the virtual serial port */
 				if (BufferCount)
 				{
 					while (BufferCount--)
-					  CDC_Device_SendByte(&VirtualSerial_CDC_Interface, RingBuffer_Remove(&Tx_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(&USARTtoUSB_Buffer)) != ENDPOINT_READYWAIT_NoError)
+						{
+							break;
+						}
+
+						/* Dequeue the already sent byte from the buffer now we have confirmed that no transmission error occurred */
+						RingBuffer_Remove(&USARTtoUSB_Buffer);
+					}
+			
 					LEDs_TurnOnLEDs(LEDMASK_RX);
 					PulseMSRemaining.RxLEDPulse = TX_RX_LED_PULSE_MS;
 				}
@@ -263,7 +273,7 @@ ISR(USART1_RX_vect, ISR_BLOCK)
 	uint8_t ReceivedByte = UDR1;
 
 	if (USB_DeviceState == DEVICE_STATE_Configured)
-	  RingBuffer_Insert(&Tx_Buffer, ReceivedByte);
+	  RingBuffer_Insert(&USARTtoUSB_Buffer, ReceivedByte);
 }
 
 /** Event handler for the CDC Class driver Host-to-Device Line Encoding Changed event.
diff --git a/Projects/USBtoSerial/USBtoSerial.c b/Projects/USBtoSerial/USBtoSerial.c
index 1dfd70896..477dd44f5 100644
--- a/Projects/USBtoSerial/USBtoSerial.c
+++ b/Projects/USBtoSerial/USBtoSerial.c
@@ -100,7 +100,17 @@ int main(void)
 
 			/* Read bytes from the USART receive buffer into the USB IN endpoint */
 			while (BufferCount--)
-			  CDC_Device_SendByte(&VirtualSerial_CDC_Interface, RingBuffer_Remove(&USARTtoUSB_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(&USARTtoUSB_Buffer)) != ENDPOINT_READYWAIT_NoError)
+				{
+					break;
+				}
+
+				/* Dequeue the already sent byte from the buffer now we have confirmed that no transmission error occurred */
+				RingBuffer_Remove(&USARTtoUSB_Buffer);
+			}
 		}
 
 		/* Load the next byte from the USART transmit buffer into the USART */
diff --git a/Projects/XPLAINBridge/XPLAINBridge.c b/Projects/XPLAINBridge/XPLAINBridge.c
index 7c824ec93..912e68367 100644
--- a/Projects/XPLAINBridge/XPLAINBridge.c
+++ b/Projects/XPLAINBridge/XPLAINBridge.c
@@ -136,9 +136,19 @@ void UARTBridge_Task(void)
 		/* 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);