CC1310: CC1310 GPTimer问题

CC1310使用GPTimer, GPTimer在开启后无法产生中断, 具体代码如下:

//频率控制
void hzirqcallback(GPTimerCC26XX_Handle handle, GPTimerCC26XX_IntMask interruptMask)
{
    LEDOR();
}

void timerhz_init(void)
{
    GPTimerCC26XX_Params params;
    GPTimerCC26XX_Params_init(&params);
    params.width          = GPT_CONFIG_32BIT;
    params.mode           = GPT_MODE_PERIODIC_UP;
    params.debugStallMode = GPTimerCC26XX_DEBUG_STALL_OFF;
    Power_setDependency(PowerCC26XX_XOSC_HF); //使能高速时钟
    hztimer = GPTimerCC26XX_open(HZGPTIMERNUM, &params);
    
    GPTimerCC26XX_Value loadVal = 48000000 / hz - 1; //47999
    GPTimerCC26XX_setLoadValue(hztimer, loadVal);
    GPTimerCC26XX_registerInterrupt(hztimer, hzirqcallback, GPT_INT_TIMEOUT);
    timerhz_setstatus(0);
}

void timerhz_setstatus(uint8_t flag)
{
    if(flag == 1) //打开频率定时器
    { 
        GPTimerCC26XX_start(hztimer);

    }
    else if(flag == 0) //关闭频率定时器
    {
        GPTimerCC26XX_stop(hztimer);
    }
}

void timerhz_sethz(uint8_t h)
{
    timerhz_setstatus(0);
    GPTimerCC26XX_Value loadVal = 48000000 / h - 1; //47999
    GPTimerCC26XX_setLoadValue(hztimer, loadVal);
}

调用GPTimerCC26XX_start后, 无法产生中断是什么原因? 怎么判断定时器是否启动?