Re: [Ftdi-usb-sio-devel] Resetting the FTDI

[Chris S. <chr...@ya...>]

From: Bill Ryder <bil...@gm...>
BR> CS> My goal is to get a message to the FT245RL and
BR> CS> back to the host within each 1ms full speed frame.
BR> 
BR> I see. That will be quite tricky I suspect.

Using a Beagle USB 480 (and the output of the ftdi_sio driver debug log), I confirmed that I am able to do this most of the time.

The Beagle USB 480 is a device that sits inline on a USB cable and records the traffic.  This screenshot was made with traffic from the application whose source I posted a couple days ago:

http://img709.imageshack.us/img709/6199/outinsingleframe.png

Note that each frame (identified by "SOF") contains:
1. the OUT request for data (0x87 0x3E)
2. The IN reply (62 byte data, 2 byte FTDI status)
3. An additional IN FTDI status (0x31 0x60)

Although this screenshot does not show it, some frames even contain two of these "ping pong" messages.  However, they are always followed by a frame containing only (0x31 0x60) limiting my "ping pong rate" to 1000 Hz.

Chris