In order to access your device using a JTAG USB interface, you need to make sure that the cable is correctly connected and that there is a live AMC13 which the iMPACT software can talk to

1. Open a terminal window, connect your device to the USB port of your Linux machine, and be sure that your device is on
2. Check the Kernel to make sure it recognizes the USB device

      $ dmesg
      [...]
      ftdi_sio 1-3:1.1: FTDI USB Serial Device converter detected
      drivers/usb/serial/ftdi_sio.c: Detected FT2232C
      usb 1-3: FTDI USB Serial Device converter now attached to ttyUSB1
      

   This message shows that my device is connected via USB port 1 on my computer
3. If the above step does not show that your device is attached to the USB port you suspect, you should disconnect the USB, wait five seconds, reconnect the USB, wait another five seconds, and then perform the dmesg command again. Unplugging and replugging the USB often fixes the problem
4. If your USB device is still not connected, be sure that your machine supports the ports you are attempting to access, and that you have permission to access them

      $ ls -l /dev/ttyUSB*
      crw-rw-rw- 1 root uucp 188, 0 Mar 26 11:37 /dev/ttyUSB0
      crw-rw-rw- 1 root uucp 188, 1 Mar 26 11:37 /dev/ttyUSB1
      

   If the user does not have root access, then he needs to contact his system administrator. If the user does have root access, but root doesn't have read and write access to the port, run the following command to change the permissions

      $ sudo chmod 666 /dev/ttyUSB*
      

5. After changing permissions correctly and after replugging the USB cable, the user should be able to identify the USB using the dmesg command.

• If the user still has trouble accessing the USB device using iMPACT, your USB port may be locked. Make sure your $LD_LIBRARY_PATH variable includes the destination of your libusb shared libraries!
  • See http://forums.xilinx.com/t5/Design-Tools-Others/Cable-connection-times-out-w-iMPACT-XMD-and-cannot-clean-cable/td-p/60647 for further details on unlocking your cable, if access still cannot be obtained.
• If the user still cannot access the USB device via impact, try running the program with the -port option, i.e.

     $ impact -port usb1
     

-- CharlieHill - 26 Mar 2013