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AR# 34855

Development Boards - Cannot connect to JTAG chain using mini-USB


When I try to connect to my Virtex-6 or Spartan-6 FPGA Development board using the mini-USB cable provided,iMPACT failsto connect to the JTAG chain and the USB device is seen as "unknown" in Device Manager.

What can I check on the boardusing my PC in order to debug this?


Virtex-6 and Spartan-6 FPGA boards allow JTAG access to the devices on the board through the mini-USB interface (J22).

JTAG configuration is provided through onboard USB-to-JTAG configuration logic, where a computer host accesses the ML605 / SP605 / SP601 JTAG chain through a Type-A (computer host side) to Type-Mini-B (board side) USB cable. This cable is shipped with the board, andgives customers access to the JTAG chain on their board without having to buy a separate Platform Cable USB I/II from Xilinx.

If you encounter problems using theUSB-A to mini-B cable, then check the following:

1) Ensure that the FMC bypass jumpers are connected between the appropriate pins.

For the ML605, jumpers J17 and J18 must be connected between pins 1-2 (bypass) to enable JTAG access to the FPGA on the base board when not using an FMC expansion module.

For the SP605, jumper J19 must be connected between pins 1-2 (bypass) to enable JTAG access to the FPGA on the basic SP605 board when not using an FMC expansion module.

For the SP601, jumper J4 must be connected between pins 1-2 for JTAG access to the FPGA on the basic SP601 board.

2) Ensure that the Found New Hardware Wizard runs when you first connect the USB cable to your PC, and make sure you follow the instructions given in the Wizard. This installs the Firmware Loader for this cable. After the USB cable has been correctly recognized and setup, you should receive the message "Your new hardware is installed and ready touse".

3) If you are having problems connecting to the JTAG chain, please try another USB port on your PC.

4) Please ensure that you are using a supported operating system with our software and cables. Check the Software Manuals for more details:http://www.xilinx.com/support/documentation/designtoolsdocumentation.htm

5) Two USB-A to mini-B cables are shipped with Development Boards; if problems are seen connecting to the JTAG chain using one of these, please swap the cable and try the second one.
AR# 34855
Date Created 08/06/2010
Last Updated 12/15/2012
Status Active
Type General Article
  • Spartan-6 LX
  • Spartan-6 LXT
  • Virtex-6 CXT
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Boards & Kits
  • Spartan-6 FPGA SP601 Evaluation Kit
  • Spartan-6 FPGA SP605 Evaluation Kit
  • Virtex-6 FPGA ML605 Evaluation Kit