TMS320C6678中的XDS560v2仿真器和CCS连接出现问题

Invalid data read back

This error varies greatly depending on the type of fault and therefore both CCS and the Test Connection can return different results.

Common to all scenarios is when the integrity scan-test fails with invalid data - something mentioned in this thread.
One example is a typical stuck-at-ones or stuck-at-zero fault:

Error connecting to the target:
(Error -233 @ 0x0)
The JTAG IR and DR scan-paths cannot circulate bits, they may be broken.
An attempt to scan the JTAG scan-path has failed.
The target's JTAG scan-path appears to be broken
with a stuck-at-ones or stuck-at-zero fault.

• If the data read back is all ones (0xFFFFFFFF), it is possible that one of the JTAG lines has a short to V_CC.
• If the data read back is all zeros (0x00000000), it is possible there is a power failure on the circuit or one of the JTAG lines has a short to GND.
• If using an isolated JTAG debug probe, it is possible that both scenarios may happen if the target board or device is powered down. In this case, make sure power is properly applied across the system.
• If the data read is garbage such as in the example below, probably reflections on the JTAG line, loose target cables or connectors or problems on the PCB routing are most probably the root causes. Also, invalid configurations such as cJTAG/JTAG or a very high TCLK speed can cause garbled data to be read back. 

http://processors.wiki.ti.com/index.php/Debugging_JTAG_Connectivity_Problems?keyMatch=dead JTAG clock.&tisearch=Search-EN

您好，我用的是TI TMS320C6678开发板，之前仿真器和CCS可以连接成功，然后能够进行程序调试，但是隔了几天之后，我再使用开发板的时候仿真器和CCS的连接出现如上问题，并且当我进行仿真器和CCS连接时，开发板上的D1-D4灯一直闪烁，之前没有出现过这种情况。请问这该如何解决呢？谢谢！