Question

Xilinx FPGA被JTAG扫到时认为FPGA为unkonw Device

Xilinx FPGA JTAG 连接上去后发现能扫到FPGA，但是认为FPGA 为unkonwn Device，用示波器测量了JTAG信号，都有，请问原因是什么？
impact提示如下：

Welcome to iMPACT
iMPACT Version: 14.7
// *** 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.
*** WARNING ***: When port is set to auto detect mode, cable speed is set to default 6 MHz regardless of explicit arguments supplied for setting the baud rates
PROGRESS_START - Starting Operation.
Connecting to cable (Usb Port - USB21).
Checking cable driver.
Driver file xusb_xlp.sys found.
Driver version: src=1029, dest=1029.
Driver windrvr6.sys version = 10.2.1.0. WinDriver v10.21 Jungo (c) 1997 - 2010 Build Date: Aug 31 2010 X86 32bit SYS 14:35:41, version = 1021.
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 F:/Xilinx/14.7/ISE_DS/ISE/datasb_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: 2015/4/14 20:11:58
// *** BATCH CMD : Identify -inferir
PROGRESS_START - Starting Operation.
Identifying chain contents...INFO:iMPACT:1588 - '0':The part does not appear to be Xilinx Part.
'0': : Manufacturer's ID =Unknown , Version : 15
INFO:iMPACT:501 - '1': Added Device UNKNOWN successfully.
----------------------------------------------------------------------
----------------------------------------------------------------------
done.
PROGRESS_END - End Operation.
Elapsed time = 1 sec.
// *** BATCH CMD : identifyMPM

若以下回答无法解决问题，邀请你更新回答

Answer 1

线速调低点试试看,盒子质量不好的话6M可能搞不定

追问

我把速度设置为750K，这个情况仍然是一样的