vivado 下载程序出错：ERROR: [Labtools 27-3165] End of startup status: LOW_end of startup status low

vivado 下载程序出错：End of startup status: LOW

open_hw_target
INFO: [Labtoolstcl 44-466] Opening hw_target localhost:3121/xilinx_tcf/Xilinx/00000000000000

INFO: [Labtools 27-1435] Device xc7a200t (JTAG device index = 0) is not programmed (DONE status = 0).

ERROR: [Labtools 27-3165] End of startup status: LOW
program_hw_devices: Time (s): cpu = 00:00:23 ; elapsed = 00:00:21 . Memory (MB): peak = 2415.988 ; gain = 485.859
ERROR: [Common 17-39] 'program_hw_devices' failed due to earlier errors.
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解决方法：
1，看JTAG引脚有没有虚焊–没有虚焊–没有解决
2，更换下载器—没有解决
3，换个测试用例–没有解决
4，换板子—ok