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Baud rate USBClient


#1

Hi there,
I am using the CDC USB Client on the FEZ Panda at 9600 baud, and I am wondering if:

  1. Is there a way to change the baud rate?
  2. If so, what is the maximum baud rate?
  3. Can someone point me to a code sample?
    Thanks,
    Greg

#2

There is no “baud rate”. This is a virtual serial interface. Changing the baud has no effect on speed


#3

I understand that it is a virtual serial interface, but I don’t quite understand why the speed can’t be changed. Perhaps I am not asking the question the right way. On the PC side, I connect to the FEZ using the below .NET C# code:


SerialPort sp = new SerialPort(port, 9600, Parity.None, 8, StopBits.One);

I want to change the 9600 to something higher speed, but the FEZ would need to be configured to talk at that speed. Am I restrictred to 9600? Is this a restriction of CDC?
Thanks!


#4

As Gus already said, a baudrate doesn’t make sense on a virtual port. I wonder what would happen if you just change the value on PC side.


#5

I really don’t understand all this, but I do know that this host side code works with FEZ CDC:


SerialPort sp = new SerialPort(port, 115200, Parity.None, 8, StopBits.One);

If anyone would care to explain, that would be helpful.


#6

Baud rate = the rate of data flowing on a wire. On USB, this is 12mbps always. When you use CDC, your PC sees the data as serial data but it is actually moving at 12mbps…you can the port on the PC at 115200 or 9600 but this would not change anything not a single bit.


#7

thank you for the explanation. I was thinking that for it to be a true virtual COM port, it would need to emulate the baud rate, but I guess it does not have to.