TMS320F28377S: DC模块中的软件编程延时寄存器EPwm4Regs.SWVDELVAL，为什么不等于EPwm4Regs.HWVDELVAL位

    问题如上，我在中断里实时改变EPwm4Regs.SWVDELVAL的值，但是EPwm4Regs.HWVDELVAL不等于EPwm4Regs.SWVDELVAL。

    //DC模块
    EPwm4Regs.DCAHTRIPSEL.bit.TRIPINPUT4 = 1;//DCAH = TRIP4
    EPwm4Regs.TZDCSEL.bit.DCAEVT1 = 2;//对选定 DCAH 信号的操作,DCAH = 高
    EPwm4Regs.DCACTL.bit.EVT1SRCSEL = 1;
    EPwm4Regs.DCACTL.bit.EVT1FRCSYNCSEL = 0;
    EPwm4Regs.DCACTL.bit.EVT1SYNCE = 1;
    //时间滤波
    EPwm4Regs.DCFCTL.bit.SRCSEL = 0;
    EPwm4Regs.DCFCTL.bit.EDGEFILTSEL = 1;   //enable edge filter
    EPwm4Regs.DCFCTL.bit.EDGEMODE = 0;      //Edge Mode Select
    EPwm4Regs.DCFCTL.bit.EDGECOUNT =1;      // Edge Count
    //谷底+延时
    EPwm4Regs.VCAPCTL.bit.TRIGSEL = 1;//选择触发源作为重置并重新启动边沿滤波器
    EPwm4Regs.VCAPCTL.bit.VCAPE = 0;//
    EPwm4Regs.VCAPCTL.bit.EDGEFILTDLYSEL = 1;//应用 DELAY
    EPwm4Regs.SWVDELVAL= Tdelay;
    //消隐窗口
    EPwm4Regs.DCFCTL.bit.BLANKE = 1;
    EPwm4Regs.DCFCTL.bit.PULSESEL = 1;
    EPwm4Regs.DCFOFFSET = 1;
    EPwm4Regs.DCFWINDOW = 1;
    EPwm4Regs.DCCAPCTL.bit.CAPE = 1;