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I'm using a FT2232H in synchronous mode, since this is the fastest transfer option for data (high data throughput is needed for the purpose of the whole design - in both directions).
The CLKOUT signal is the clock given to me from the FTDI (60MHz).
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Ok, thanks.
How are you going to generate USB traffic? FTDI's libftd2xx works fine under Windows and Linux. The open-source libraries libusb, libusb-1.0, libftdi, and libftdi-1.0 are a bit more fragmented, and were not so windows friendly.
The other useful thing to do while testing, is to use Wireshark under Linux to trace the USB bus traffic (Wireshark under Windows does not have a USB tracing option). If you're running Windows XP, then you can also install VirtualBox, Linux inside VirtualBox, give the FTDI device to the virtual machine, and trace the USB traffic from Wireshark in there. Using Windows 7 as a host does not work as well, as it does not like to give the USB-Blaster to the VM (but it'll give the FTDI device to the VM).
One other problem I have run into, and have yet to solve, is that I get conflicts with the FTDI driver and USB-Blaster. Eg., if I have SystemConsole with a JTAG connection open, I cannot access the FTDI device via the COM port, until the JTAG connection is closed. This makes it a pain to trigger SignalTap II for tracing USB traffic once it reaches the FPGA.
I'd be interested in hearing what data rates you end up getting over the synchronous FTDI interface.
Cheers,
Dave
Honored Contributor
