The following iMPACT Error Message is displayed when iMPACT is started:
"ERROR:iMPACT:585 - A problem may exist in the hardware configuration. Check that the cable, scan chain, and power connections are intact, that the specified scan chain configuration matches the actual hardware, and that the power supply is adequate and delivering the correct voltage."
For more iMPACT Error Articles and other Configuration Related Articles, see (Xilinx Answer 34104).
This error typically occurs when the cable is not fully functional. The cable requires the proper drives to be installed and the cable be connected to a board properly.
The cable should be present at the bottom right side of the iMPACT GUI. The iMPACT software will allow the cable speed to be changed and this can be tested to ensure the cable is connected properly. This test can be run prior to connecting the cable to a board.
When the cable is connected to the board there is an LED that needs to turn Green prior to successful operation. If this LED is Red or Orange the cable connection to the board may not in tact. The Cable Data Sheet has the voltage requirements for the Vref pin on the header.
There are also scenarios in which the devices under test may cause the JTAG logic to be unaccessible.
1. This error message will occur if the reserved PWRDWN_B pin is incorrectly held Low.
1. This error message will be reported if the /PROG pin is held Low while an attempt to initialize the chain is made. Ensure that the PROGRAM pin is High, as it will reset the TAP controller, preventing iMPACT from detecting the device in the chain. The PROGRAM pin does not reset the TAP controller for Virtex-II/-II Pro devices.
Chains containing third-party devices:
1. Many third-party devices are not boundary scan-compliant and might break the JTAG chain. Check the "Design Warning" section in the BSDL file for the third-party device to learn about known problems with these parts.
2. Considerations for the optional /TRST signal:
Many third-party devices implement the optional /TRST signal. Ensure that the /TRST signal is High at all times when you attempt to perform JTAG operations.
For example, many Texas Instruments DSPs have a pull-down resistor on the optional /TRST signal, which causes these devices to remain in reset. The /TRST signal should have a pull-up resistor, which will prevent it from breaking the JTAG chain if left unconnected.
Mixed Voltage Chains/Noisy JTAG lines:
Check to see what I/O voltages are being used on the chain. Mixing signals is supported so long as extra care is taken to make sure the signal levels do not linger or ring around the threshold value (CMOS 50% of VI/OH). On the TDO side, a pull-up can help sharpen the signal when transitioning over to tri-state mode. Another thing to consider is putting a parallel termination on TDO so that you sharpen the signal going back to the cable.