Fez Flea to Endpoint CDC Driver

Endpoint
1

Does the Endpoint have the CDC driver so that the SC13XX type devices can connect to it?

I have the Fez Flea in USB CDC mode, but the Enpoint’s Linux environment doesn’t see it at all. there is no /dev/ttyACM0 showing up.

2 
        if (!File.Exists("/dev/ttyACM0"))
        {
            Process.Start("modprobe", "cdc_acm")?.WaitForExit();
            Thread.Sleep(1000);
        }

        var serial = new System.IO.Ports.SerialPort("/dev/ttyACM0", 115200);
        serial.Open();
        var data = Encoding.UTF8.GetBytes("Hello World");
        serial.Write(data,0,data.Length);
        serial.Close();

I figured out how to start CDC on EndPoint. That modprobe thing should really be in some sort of startup script by default on the Endpoint SD image.

2 Likes
3

Sometimes the Flea will lockup and stop responding to the endpoint. So I stopped using CDC. Seems it isn’t that much faster than UART anyway.

4

To me CDC is much faster, if you can reproduce it with simple code, we can take a look.

5

Reproducing it is difficult. The Fez Flea was configured for Serial Debugging and sometimes either the code would block or the debugging would slow it down. The result is that the CDC channel stops working on the Endpoint side, and only replugging the Fez Flea resolved the issue. No amount of rebooting the Endpoint solved it.

The slowness complaint was regarding the baud rate. Even though we have 580mbps over usb I can’t get more than 912600 baud. I mean what’s the point of CDC if it’s only as fast a normal UART? Its only a little more reliable. If I use Reed-Solomon codes, I’m sure I can get at least 800Kbaud!

6

I think it is more like 12mbps on Flea side?

7

Is Flea only USB 1.1?

8

I believe so, but I have often been wrong. Just ask my wife.

1 Like