关于Beagle Bone Black 板子JTAG调试链接不上的问题

硬件平台：Beagle Bone Black
软件平台：CCS5.4
仿真器：XDS100V2
JTAG：采用飞线的方式，将20芯转为14芯，然后与仿真器连接
问题描述：
     采用CCS5.4去调试，在test configuration的时候弹出以下错误信息：
[Start]

Execute the command:

%ccs_base%/common/uscif/dbgjtag -f %boarddatafile% -rv -o -F inform,logfile=yes -S pathlength -S integrity

[Result]


-----[Print the board config pathname(s)]------------------------------------

C:UsersLKLAppDataLocal.TI693494126
    0BrdDattestBoard.dat

-----[Print the reset-command software log-file]-----------------------------

This utility has selected a 100- or 510-class product.
This utility will load the adapter 'jioserdesu***.dll'.
The library build date was 'Apr  1 2013'.
The library build time was '23:55:08'.
The library package version is '5.1.73.0'.
The library component version is '35.34.40.0'.
The controller does not use a programmable FPGA.
The controller has a version number of '4' (0x00000004).
The controller has an insertion length of '0' (0x00000000).
This utility will attempt to reset the controller.
This utility has successfully reset the controller.

-----[Print the reset-command hardware log-file]-----------------------------

The scan-path will be reset by toggling the JTAG TRST signal.
The controller is the FTDI FT2232 with USB interface.
The link from controller to target is direct (without cable).
The software is configured for FTDI FT2232 features.
The controller cannot monitor the value on the EMU[0] pin.
The controller cannot monitor the value on the EMU[1] pin.
The controller cannot control the timing on output pins.
The controller cannot control the timing on input pins.
The scan-path link-delay has been set to exactly '0' (0x0000).

-----[The log-file for the JTAG TCLK output generated from the PLL]----------

There is no hardware for programming the JTAG TCLK frequency.

-----[Measure the source and frequency of the final JTAG TCLKR input]--------

There is no hardware for measuring the JTAG TCLK frequency.

-----[Perform the standard path-length test on the JTAG IR and DR]-----------

This path-length test uses blocks of 512 32-bit words.

The JTAG IR instruction path-length was not recorded.

-----[Perform the Integrity scan-test on the JTAG IR]------------------------

This test will use blocks of 512 32-bit words.
This test will be applied just once.

Do a test using 0xFFFFFFFF.
Scan tests: 1, skipped: 0, failed: 0

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

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

The value is '-183' (0xffffff49).
The title is 'SC_ERR_CTL_CBL_BREAK_FAR'.

The explanation is:
The controller has detected a cable break far-from itself.
The user must connect the cable/pod to the target.

[End]
这个时候我们PC端仿真器的驱动是显示安装成功的。
另外之前网上看到说可能JTAG管脚的问题，我也已经把20芯JTAG的第15脚SRST接到14芯的2脚TRST上了。错误依旧如上。
另外还有尝试了上电的时候摁住S2开关，不让板子启动FLASH里面的操作系统，虽然系统没有启动，但是错误依旧如上。
请问大神，这是什么原因造成的？