DSP28035 EPMWxB无输出

求助，DSP28035 EPWMxB无PWM波，A组有，B组可以配置为GPIO口，可以输出高电平 ，就是没有PWM波，配置寄存器如下：

    EPwm5Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP; // Count up
    EPwm5Regs.TBPRD = EPWMx_TIMER_TBPRD;       // Set timer period
    EPwm5Regs.TBCTL.bit.PHSEN = TB_DISABLE;    // Disable phase loading
    EPwm5Regs.TBPHS.half.TBPHS = 0x0000;       // Phase is 0
    EPwm5Regs.TBCTR = 0x0000;                  // Clear counter
    EPwm5Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1;   // Clock ratio to SYSCLKOUT
    EPwm5Regs.TBCTL.bit.CLKDIV = TB_DIV1;
    EPwm5Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
    EPwm5Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
    EPwm5Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO;
    EPwm5Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO;
    EPwm5Regs.AQCTLA.bit.CAU = AQ_CLEAR;
    EPwm5Regs.AQCTLA.bit.ZRO = AQ_SET;
    EPwm5Regs.AQCTLB.bit.CAU = AQ_CLEAR;
    EPwm5Regs.AQCTLB.bit.ZRO = AQ_SET;
    EPwm5Regs.CMPA.half.CMPA = 0;
    EPwm5Regs.CMPB = 3000;