Xilinx efuse后问题求助

zfgu

使用密钥加密，采用EFUSE方式，烧写密钥后少些MCS文件成功，测试也没有问题。
当再次烧写密钥时，显示CRC错误，错误信息如下，请各位大侠帮忙解决下，谢谢

INFO:iMPACT - Current time:           2PROGRESS_START - Starting Operation.
Maximum TCK operating frequency for this device chain: 25000000.
Validating chain...
Boundary-scan chain validated successfully.
'1': SPI access core not detected. SPI access core will be downloaded to the device to enable operations.
INFO:iMPACT - Downloading core file C:/Xilinx/12.3/ISE_DS/ISE/spartan6/data/xc6slx75_spi.cor.
'1': Downloading core...
LCK_cycle = NoWait.
LCK cycle: NoWait
done.
'1': Reading status register contents...
WARNING:iMPACT:2217 - Error shows in the status register, CRC Error bit is NOT 0.
INFO:iMPACT:2219 - Status register values:
INFO:iMPACT - 1000 0000 1100 0000
INFO:iMPACT:2492 - '1': Completed downloading core to device.
INFO:iMPACT - '1': Flash was not programmed successfully.
PROGRESS_END - End Operation.