[CC2640R2F] 为什么我无法使用Registers窗口查看TIMER寄存器的变化？

    //PWM_Parameter_SET
    PWM_init();
    PWM_Params_init(&pwmParams);
    pwmParams.idleLevel = PWM_IDLE_LOW;
    pwmParams.periodUnits = PWM_PERIOD_HZ;
    pwmParams.periodValue = 1e6;
    pwmParams.dutyUnits = PWM_DUTY_FRACTION;
    pwmParams.dutyValue = PWM_DUTY_FRACTION_MAX / 2;
    //Log_info1("Board_PWM1:%d",Board_PWM1);
    pwm = PWM_open(Board_PWM1, &pwmParams);
    if(pwm == NULL)
    {
        Log_error0("PWM_open error!");
        Task_exit();
    }

我在Project_zero工程的Project_init中添加了上述代码，但我在debug状态下无法跟踪到TIMER的寄存器变化，这是为什么？