TI中文支持网我用的开发板是TMDSEVM6678LE，CCS版本是5.2，仿真器是TI XDS100v3。将开发板上的560v2仿真器拆下，我们自己将6678的JTAG引脚从开发板AMC边沿连接器端上引出，做成14引脚的JTAG测试接口。在CCS5.2的连接配置文件的“Connection”中选择的是XDS100v3，“Device”中选择的是TMS320C6678。在test connection时，提示如下错误：
[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:\Users\ADMINI~1\AppData\Local\.TI\213602635\
0\0\BrdDat\testBoard.dat
—–[Print the reset-command software log-file]—————————–
This utility has selected a 100- or 510-class product.
This utility will load the adapter 'jioserdesusbv3.dll'.
The library build date was 'Apr 27 2016'.
The library build time was '23:27:56'.
The library package version is '6.0.228.0'.
The library component version is '35.35.0.0'.
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).
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 '-501' (0xfffffe0b).
The title is 'SC_ERR_TEST_MEASURE'.
The explanation is:
The built-in scan-path length measurement failed.
The built-in scan-path reliability tests cannot be
performed without knowledge of the scan-path length.
Try specifying the scan-path lengths in the command-line
options or board configuration file of this utility or debugger.
在14引脚header的接口的硬件连接方面，我们已经核对了好几遍，没有发现什么错误，现在不知道问题出在哪里。'-501'这个错误我在文档Debugging JTAG Connectivity Problems.pdf中也没有找到，现在我不清楚这一错误应该从哪里着手去解决，请TI的工程师给予指导。
Allen35065：
JTAG环路检测不到信号，为什么要把这个JTAG引出来？
