JTAG检测不到Vertex-5器件，但能检测flash

xidianuser

如题，采用主串模式，JTAG先接XC32p，然后16P，然后V5。V5电路之前用过，这次照抄。用JTAG扫描时发现如下现状，然后将XC16P的
TDO输出直接接JTAG,能识别32P和16P。测试V5的JTAG，有阻值，未短路，请问，有什么问题？


Welcome to iMPACT
iMPACT Version: 12.2
Project: C:\Xilinx\12.2\ISE_DS\\auto_project.ipf created.
// *** BATCH CMD : setMode -bs
// *** BATCH CMD : setMode -bs
// *** BATCH CMD : setMode -bs
// *** BATCH CMD : setMode -bs
GUI --- Auto connect to cable...
// *** BATCH CMD : setCable -port auto
AutoDetecting cable. Please wait.
PROGRESS_START - Starting Operation.
Connecting to cable (Usb Port - USB21).
Checking cable driver.
Driver file xusb_emb.sys found.
Driver version: src=1029, dest=1029.
Driver windrvr6.sys version = 8.1.1.0. WinDriver v8.11 Jungo (c) 1997 - 2007 Build Date: Feb 28 2007 x86_64 64bit SYS 09:48:01, version = 811.
Cable PID = 0008.
Max current requested during enumeration is 74 mA.
Type = 0x0004.
Cable Type = 3, Revision = 0.
Setting cable speed to 6 MHz.
Cable connection established.
Firmware version = 1303.
File version of C:/Xilinx/12.2/ISE_DS/ISE/data/xusb_xlp.hex = 1303.
Firmware hex file version = 1303.
PLD file version = 0012h.
PLD version = 0012h.
PROGRESS_END - End Operation.
Elapsed time =      0 sec.
Type = 0x0004.
ESN device is not available for this cable.
Attempting to identify devices in the boundary-scan chain configuration...
INFO:iMPACT - Current time: ���� ���� // *** BATCH CMD : Identify -inferir
PROGRESS_START - Starting Operation.
Identifying chain contents...done.
ERROR:iMPACT - 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.
PROGRESS_END - End Operation.
Elapsed time =      0 sec.
// *** BATCH CMD : identifyMPM
5 16:23:28 2015