我用blackhawk接28335，测试接口出现如下提示
The controller is the Nano-TBC VHDL.
The link is a 560-class second-generation-560 cable.
The software is configured for Nano-TBC VHDL features.
The controller will be software reset via its registers.
The controller has a logic ONE on its EMU[0] input pin.
The controller has a logic ONE on its EMU[1] input pin.
The controller will use falling-edge timing on output pins.
The controller cannot control the timing on input pins.
The scan-path link-delay has been set to exactly '2' (0x0002).
The utility logic has not previously detected a power-loss.
The utility logic is not currently detecting a power-loss.
Loaded FPGA Image: D:ccs5.5ccsv5ccs_basecommonuscifdtc_top.jbc

An error occurred while hard opening the controller.

-----[An error has occurred and this utility has aborted]--------------------

This error is generated by TI's USCIF driver or utilities.

The value is '-234' (0xffffff16).
The title is 'SC_ERR_PATH_IR_BROKEN'.

The explanation is:
The instruction scan-path cannot circulate bits, it may be broken.
An attempt to scan the JTAG instruction registers has failed.
The target's JTAG instruction path appears to be broken
with a stuck-at-ones or stuck-at-zero fault.
这是啥情况