Fix XPLAINBridge project discarding characters from the USB interface due to a double read from the endpoint.

Make XPLAINBridge and USBtoSerial projects more reliable by forcing a flush if the UART-to-USB buffer becomes nearly full.

Reduce locking in the LightweightRingBuffer.h header files by only locking on the update of the buffer count, and require insertions and removals from each buffer to occur in only one execution thread.

Fix CDC_*_ReceiveByte() returning 0 when the interface is not configured, instead of the new -1 error value.

Fix CDC_Host_ReceiveByte() not re-freezing the pipe if no packet has been received.

Remove redundant Pipe token set commands in the CDC and RNDIS host class drivers.

1 files changed, 8 insertions, 7 deletions

diff --git a/Projects/USBtoSerial/USBtoSerial.c b/Projects/USBtoSerial/USBtoSerial.c
index 4f3fcf524..c2ecc7cf4 100644
--- a/Projects/USBtoSerial/USBtoSerial.c
+++ b/Projects/USBtoSerial/USBtoSerial.c
@@ -84,21 +84,22 @@ int main(void)
 		/* Read bytes from the USB OUT endpoint into the USART transmit buffer */
 		int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
 		if (!(ReceivedByte < 0) && !(RingBuffer_IsFull(&USBtoUSART_Buffer)))
-		  RingBuffer_AtomicInsert(&USBtoUSART_Buffer, (uint8_t)ReceivedByte);		
+		  RingBuffer_Insert(&USBtoUSART_Buffer, ReceivedByte);		
 		
-		/* Check if the UART receive buffer flush timer has expired */
-		if (TIFR0 & (1 << TOV0))
+		/* Check if the UART receive buffer flush timer has expired or the buffer is nearly full */
+		RingBuff_Count_t BufferCount = RingBuffer_GetCount(&USARTtoUSB_Buffer);
+		if ((TIFR0 & (1 << TOV0)) || (BufferCount > 200))
 		{
 			TIFR0 |= (1 << TOV0);
 
 			/* Read bytes from the USART receive buffer into the USB IN endpoint */
-			while (USARTtoUSB_Buffer.Count)
-			  CDC_Device_SendByte(&VirtualSerial_CDC_Interface, RingBuffer_AtomicRemove(&USARTtoUSB_Buffer));
+			while (BufferCount--)
+			  CDC_Device_SendByte(&VirtualSerial_CDC_Interface, RingBuffer_Remove(&USARTtoUSB_Buffer));
 		}
 		
 		/* Load the next byte from the USART transmit buffer into the USART */
-		if (USBtoUSART_Buffer.Count)
-		  Serial_TxByte(RingBuffer_AtomicRemove(&USBtoUSART_Buffer));
+		if (!(RingBuffer_IsEmpty(&USBtoUSART_Buffer)))
+		  Serial_TxByte(RingBuffer_Remove(&USBtoUSART_Buffer));
 		
 		CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
 		USB_USBTask();