环境：
1）自己的板子
2) 通过开发板的FTDI模块进行调试及烧写
3）将板子的SWD 2 线 烧录串口2线 复位 及电源 连接到 开发板相应的接口
出现如下问题：
[17:54:54] Begin ServicePackProgramming operation.
[17:54:56] INFO: > Executing Operation: Connect
[17:54:58] INFO: setting break signal
[17:54:59] INFO: detecting FTDI for device reset
[17:55:14] ERROR: ---reading ACK signal failed---
[17:55:14] WARNING: ---seting break signal to false failed---
[17:55:16] INFO: setting break signal
[17:55:17] INFO: detecting FTDI for device reset
[17:55:20] Cancelling current process <ServicePackProgramming>, please wait...
[17:55:33] ERROR: ---reading ACK signal failed---
[17:55:33] WARNING: ---seting break signal to false failed---
我们在调试过程中，将串口rx tx 线对调及外接复位信号等都进行了尝试，但一直重复出现上述错误。请问是什么问题呢？
