1、控制板卡连接不上，debug显示如下错误，示波器采集XRS(F19引脚)获得一个140us的低脉冲，测量3.3V，1.2V电压均正常，且平时XRS为高电平（3.3v）
C28xx_CPU1: Error: (Error -1137 @ 0x0) Device is held in reset. Take the device out of reset, and retry the operation. (Emulation package 8.1.0.00005)
C28xx_CPU1: Unable to determine target status after 20 attempts
C28xx_CPU1: Failed to remove the debug state from the target before disconnecting. There may still be breakpoint op-codes embedded in program memory. It is recommended that you reset the emulator before you connect and reload your program before you continue debugging
C28xx_CPU1: Error occurred during flash operation: Could not read 0x0007026D@Data: target is not connected
C28xx_CPU1: Error occurred during flash operation: Could not write 0x0005F444@Data: target is not connected
C28xx_CPU1: Error occurred during flash operation: Could not read 0x0005F444@Data: target is not connected
C28xx_CPU1: Error occurred during flash operation: Could not read 0x00130@Program: target is not connected
C28xx_CPU1: Error executing PLL configuration algorithm. Operation cancelled. (0x0)
C28xx_CPU1: Error occurred during flash operation: Could not write 0x0005D200@Data: target is not connected
C28xx_CPU1: File Loader: Memory write failed: Unknown error
C28xx_CPU1: GEL: File: C:\Users\LiuJun\workspace_v9\LAN9252_SPI_379\Debug\LAN9252_SPI_379.out: Load failed.
C28xx_CPU1: Error occurred during flash operation: Could not read register PC: target is not connected
C28xx_CPU1: Error occurred during flash operation: Could not write 0x0005F800@Data: target is not connected
C28xx_CPU1: Error occurred during flash operation: Could not write 0x00000@Program: target is not connected
C28xx_CPU1: Error occurred during flash operation: Cannot enable while the target is disconnected
