Add explicit guards to all device mode tasks to ensure the device is connected and configured before running the task, to prevent any user tasks from locking up the main USB task if the device has not been properly configured.

1 files changed, 70 insertions, 69 deletions

diff --git a/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c b/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
index c48c33c08..9160dd107 100644
--- a/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
+++ b/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
@@ -204,89 +204,90 @@ void EVENT_USB_UnhandledControlPacket(void)
 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */

 void CDC_Task(void)

 {

-	if (USB_IsConnected)

-	{

+	/* Device must be connected and configured for the task to run */

+	if (!(USB_IsConnected) || !(USB_ConfigurationNumber))

+	  return;

+	  

 #if 0

-		/* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232

-				 handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:

-		*/

+	/* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232

+			 handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:

+	*/

 

-		USB_Notification_Header_t Notification = (USB_Notification_Header_t)

-			{

-				.NotificationType = (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),

-				.Notification     = NOTIF_SerialState,

-				.wValue           = 0,

-				.wIndex           = 0,

-				.wLength          = sizeof(uint16_t),

-			};

-			

-		uint16_t LineStateMask;

-		

-		// Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host

+	USB_Notification_Header_t Notification = (USB_Notification_Header_t)

+		{

+			.NotificationType = (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),

+			.Notification     = NOTIF_SerialState,

+			.wValue           = 0,

+			.wIndex           = 0,

+			.wLength          = sizeof(uint16_t),

+		};

 		

-		Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);

-		Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));

-		Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));

-		Endpoint_ClearIN();

+	uint16_t LineStateMask;

+	

+	// Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host

+	

+	Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);

+	Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));

+	Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));

+	Endpoint_ClearIN();

 #endif

 

-		/* Select the Serial Rx Endpoint */

-		Endpoint_SelectEndpoint(CDC_RX_EPNUM);

-		

-		/* Check to see if a packet has been received from the host */

-		if (Endpoint_IsOUTReceived())

+	/* Select the Serial Rx Endpoint */

+	Endpoint_SelectEndpoint(CDC_RX_EPNUM);

+	

+	/* Check to see if a packet has been received from the host */

+	if (Endpoint_IsOUTReceived())

+	{

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

+		while (Endpoint_BytesInEndpoint() && (Rx_Buffer.Elements != BUFF_STATICSIZE))

 		{

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

-			while (Endpoint_BytesInEndpoint() && (Rx_Buffer.Elements != BUFF_STATICSIZE))

-			{

-				/* Store each character from the endpoint */

-				Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());

-			}

-			

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

-			if (!(Endpoint_BytesInEndpoint()))

-			{

-				/* Clear the endpoint buffer */

-				Endpoint_ClearOUT();

-			}

+			/* Store each character from the endpoint */

+			Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());

 		}

 		

-		/* Check if Rx buffer contains data - if so, send it */

-		if (Rx_Buffer.Elements)

-		  Serial_TxByte(Buffer_GetElement(&Rx_Buffer));

+		/* 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 - if so, send it */

+	if (Rx_Buffer.Elements)

+	  Serial_TxByte(Buffer_GetElement(&Rx_Buffer));

+

+	/* Select the Serial Tx Endpoint */

+	Endpoint_SelectEndpoint(CDC_TX_EPNUM);

 

-		/* Select the Serial Tx Endpoint */

-		Endpoint_SelectEndpoint(CDC_TX_EPNUM);

+	/* Check if the Tx buffer contains anything to be sent to the host */

+	if (Tx_Buffer.Elements)

+	{

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

+		while (!(Endpoint_IsReadWriteAllowed()));

+		

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

+		while (Tx_Buffer.Elements && Endpoint_IsReadWriteAllowed())

+		{

+			/* 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();

 

-		/* Check if the Tx buffer contains anything to be sent to the host */

-		if (Tx_Buffer.Elements)

+		/* 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()));

-			

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

-			while (Tx_Buffer.Elements && Endpoint_IsReadWriteAllowed())

-			{

-				/* 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();

 

-			/* 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();

 		}

 	}

 }