UNIFLASH: UniFlashL烧录F2800157时报错

Part Number: UNIFLASH
Other Parts Discussed in Thread: LAUNCHXL-F2800157,

我使用LAUNCHXL-F2800157开发板,CCS下载仿真都正常,使用UniFlashL烧录F2800157时报错
[ERROR] IcePick_C_0: Error connecting to the target: (Error -2131 @ 0x0) Unable to access device register. Reset the device, and retry the operation. If error persists, confirm configuration, power-cycle the board, and/or try more reliable JTAG settings (e.g. lower TCLK). (Emulation package 21.0.0.3955) 
uniflash试了两个版本都是一样
uniflash_sl.9.5.0.5651
uniflash_sl.9.6.0.5764