Better fix for LowLevel CDC demo issue where sending data before the line encoding is set will cause a failure of the host to open the port. Added fix to the DualCDC and USBtoSerial LowLevel demos.

1 files changed, 15 insertions, 17 deletions

diff --git a/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c b/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
index af963b1fc..2765064f7 100644
--- a/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
+++ b/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
@@ -36,10 +36,10 @@
  *  These values are set by the host via a class-specific request, and the physical USART should be reconfigured to match the

  *  new settings each time they are changed by the host.

  */

-CDC_Line_Coding_t LineCoding = { .BaudRateBPS = 9600,

-                                 .CharFormat  = OneStopBit,

-                                 .ParityType  = Parity_None,

-                                 .DataBits    = 8            };

+CDC_Line_Coding_t LineEncoding = { .BaudRateBPS = 0,

+                                   .CharFormat  = OneStopBit,

+                                   .ParityType  = Parity_None,

+                                   .DataBits    = 8            };

 

 /** Ring (circular) buffer to hold the RX data - data from the host to the attached device on the serial port. */

 RingBuff_t Rx_Buffer;

@@ -145,8 +145,6 @@ void EVENT_USB_ConfigurationChanged(void)
  */

 void EVENT_USB_UnhandledControlPacket(void)

 {

-	uint8_t* LineCodingData = (uint8_t*)&LineCoding;

-

 	/* Process CDC specific control requests */

 	switch (USB_ControlRequest.bRequest)

 	{

@@ -157,7 +155,7 @@ void EVENT_USB_UnhandledControlPacket(void)
 				Endpoint_ClearSETUP();

 

 				/* Write the line coding data to the control endpoint */

-				Endpoint_Write_Control_Stream_LE(LineCodingData, sizeof(LineCoding));

+				Endpoint_Write_Control_Stream_LE(&LineEncoding, sizeof(LineEncoding));

 				

 				/* Finalize the stream transfer to send the last packet or clear the host abort */

 				Endpoint_ClearOUT();

@@ -171,7 +169,7 @@ void EVENT_USB_UnhandledControlPacket(void)
 				Endpoint_ClearSETUP();

 

 				/* Read the line coding data in from the host into the global struct */

-				Endpoint_Read_Control_Stream_LE(LineCodingData, sizeof(LineCoding));

+				Endpoint_Read_Control_Stream_LE(&LineEncoding, sizeof(LineEncoding));

 

 				/* Finalize the stream transfer to clear the last packet from the host */

 				Endpoint_ClearIN();

@@ -259,7 +257,7 @@ void CDC_Task(void)
 	Endpoint_SelectEndpoint(CDC_TX_EPNUM);

 

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

-	if (Tx_Buffer.Elements)

+	if ((Tx_Buffer.Elements) && LineEncoding.BaudRateBPS)

 	{

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

 		while (!(Endpoint_IsReadWriteAllowed()))

@@ -304,7 +302,7 @@ void CDC_Task(void)
 ISR(USART1_RX_vect, ISR_BLOCK)

 {

 	/* Only store received characters if the USB interface is connected */

-	if (USB_DeviceState != DEVICE_STATE_Configured)

+	if ((USB_DeviceState != DEVICE_STATE_Configured) && LineEncoding.BaudRateBPS)

 	  Buffer_StoreElement(&Tx_Buffer, UDR1);

 }

 

@@ -314,21 +312,21 @@ void ReconfigureUSART(void)
 	uint8_t ConfigMask = 0;

 

 	/* Determine parity - non odd/even parity mode defaults to no parity */

-	if (LineCoding.ParityType == Parity_Odd)

+	if (LineEncoding.ParityType == Parity_Odd)

 	  ConfigMask = ((1 << UPM11) | (1 << UPM10));

-	else if (LineCoding.ParityType == Parity_Even)

+	else if (LineEncoding.ParityType == Parity_Even)

 	  ConfigMask = (1 << UPM11);

 

 	/* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */

-	if (LineCoding.CharFormat == TwoStopBits)

+	if (LineEncoding.CharFormat == TwoStopBits)

 	  ConfigMask |= (1 << USBS1);

 

 	/* Determine data size - 5, 6, 7, or 8 bits are supported */

-	if (LineCoding.DataBits == 6)

+	if (LineEncoding.DataBits == 6)

 	  ConfigMask |= (1 << UCSZ10);

-	else if (LineCoding.DataBits == 7)

+	else if (LineEncoding.DataBits == 7)

 	  ConfigMask |= (1 << UCSZ11);

-	else if (LineCoding.DataBits == 8)

+	else if (LineEncoding.DataBits == 8)

 	  ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));

 	

 	/* Enable double speed, gives better error percentages at 8MHz */

@@ -341,5 +339,5 @@ void ReconfigureUSART(void)
 	UCSR1C = ConfigMask;

 	

 	/* Set the USART baud rate register to the desired baud rate value */

-	UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineCoding.BaudRateBPS);

+	UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineEncoding.BaudRateBPS);

 }