Fixed CDC and USBtoSerial demos freezing where buffers were full while still transmitting or receiving (thanks to Peter Hand).

2 files changed, 38 insertions, 18 deletions

diff --git a/Demos/Device/CDC/CDC.c b/Demos/Device/CDC/CDC.c
index 3dc624057..29bc00373 100644
--- a/Demos/Device/CDC/CDC.c
+++ b/Demos/Device/CDC/CDC.c
@@ -300,14 +300,22 @@ TASK(CDC_Task)
 		/* Write the String to the Endpoint */

 		Endpoint_Write_Stream_LE(ReportString, strlen(ReportString));

 		

+		/* Remember if the packet to send completely fills the endpoint */

+		bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);

+

 		/* Finalize the stream transfer to send the last packet */

 		Endpoint_ClearIN();

 

-		/* Wait until the endpoint is ready for another packet */

-		while (!(Endpoint_IsINReady()));

-		

-		/* Send an empty packet to ensure that the host does not buffer data sent to it */

-		Endpoint_ClearIN();

+		/* If the last packet filled the endpoint, send an empty packet to release the buffer on 

+		 * the receiver (otherwise all data will be cached until a non-full packet is received) */

+		if (IsFull)

+		{

+			/* Wait until the endpoint is ready for another packet */

+			while (!(Endpoint_IsINReady()));

+			

+			/* Send an empty packet to ensure that the host does not buffer data sent to it */

+			Endpoint_ClearIN();

+		}

 	}

 

 	/* Select the Serial Rx Endpoint */

diff --git a/Demos/Device/USBtoSerial/USBtoSerial.c b/Demos/Device/USBtoSerial/USBtoSerial.c
index 87d531c4d..1d238aa11 100644
--- a/Demos/Device/USBtoSerial/USBtoSerial.c
+++ b/Demos/Device/USBtoSerial/USBtoSerial.c
@@ -246,18 +246,19 @@ TASK(CDC_Task)
 		

 		if (Endpoint_IsOUTReceived())

 		{

-			/* Read the received data endpoint into the transmission buffer */

-			while (Endpoint_BytesInEndpoint())

+			/* Read the bytes in from the endpoint into the buffer while space is available */

+			while (Endpoint_BytesInEndpoint() && (BUFF_STATICSIZE - Rx_Buffer.Elements))

 			{

-				/* Wait until the buffer has space for a new character */

-				while (!((BUFF_STATICSIZE - Rx_Buffer.Elements)));

-			

 				/* Store each character from the endpoint */

 				Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());

 			}

 			

-			/* Clear the endpoint buffer */

-			Endpoint_ClearOUT();

+			/* Check to see if all bytes in the current packet have been read */

+			if (!(Endpoint_BytesInEndpoint()))

+			{

+				/* Clear the endpoint buffer */

+				Endpoint_ClearOUT();

+			}

 		}

 		

 		/* Check if Rx buffer contains data */

@@ -280,18 +281,29 @@ TASK(CDC_Task)
 			/* Wait until Serial Tx Endpoint Ready for Read/Write */

 			while (!(Endpoint_IsReadWriteAllowed()));

 			

-			/* Write the transmission buffer contents to the received data endpoint */

+			/* Write the bytes from the buffer to the endpoint while space is available */

 			while (Tx_Buffer.Elements && (Endpoint_BytesInEndpoint() < CDC_TXRX_EPSIZE))

-			  Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));

+			{

+				/* Write each byte retreived from the buffer to the endpoint */

+				Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));

+			}

+			

+			/* Remember if the packet to send completely fills the endpoint */

+			bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);

 			

 			/* Send the data */

 			Endpoint_ClearIN();

 

-			/* Wait until Serial Tx Endpoint Ready for Read/Write */

-			while (!(Endpoint_IsReadWriteAllowed()));

+			/* If no more data to send and the last packet filled the endpoint, send an empty packet to release

+			 * the buffer on the receiver (otherwise all data will be cached until a non-full packet is received) */

+			if (IsFull && !(Tx_Buffer.Elements))

+			{

+				/* Wait until Serial Tx Endpoint Ready for Read/Write */

+				while (!(Endpoint_IsReadWriteAllowed()));

 

-			/* Send an empty packet to terminate the transfer */

-			Endpoint_ClearIN();

+				/* Send an empty packet to terminate the transfer */

+				Endpoint_ClearIN();

+			}

 		}

 	}

 }