UART串口进入不了中断是怎么回事？求解答

void USART0_IRQHandler(void)
{
    if(usart_interrupt_flag_get(USART0,USART_INT_FLAG_RBNE) != RESET)   
    {
        USART0_ReceiveFifo[USART0_ReceiveFifoEp_ZC] =  usart_data_receive(USART0);
        USART0_ReceiveFifoEp_ZC++;
        USART0_ReceiveFifoEp_SL++;
        if(USART0_ReceiveFifoEp_ZC == USART0_ReceiveFifoSp_ZC)
        {
            USART0_ReceiveFifoSp_ZC++;
        }
    if(USART0_ReceiveFifoEp_SL == USART0_ReceiveFifoSp_SL)
        {
            USART0_ReceiveFifoSp_SL++;
        }
        USART0_ReceiveFifotime_ZC = 0;   
        USART0_ReceiveFifoTime_SL = 0;   
    }
    if(usart_interrupt_flag_get(USART0,USART_INT_FLAG_TBE) != RESET)   
    {
        if(USART0_SendFifoSp != USART0_SendFifoEp)
        {
            usart_data_transmit(USART0, USART0_SendFifo[USART0_SendFifoSp++]);
        }
        if(USART0_SendFifoSp == USART0_SendFifoEp)
        {
            usart_interrupt_disable(USART0,USART_INT_TBE);
        }
    }
}

uint8_t USART0_ReadFifo_ZC(uint8_t *Buff)
{
    uint8_t Sp;
    uint8_t Ep;
    uint8_t Len = 0;
   
    Sp = USART0_ReceiveFifoSp_ZC;
    Ep = USART0_ReceiveFifoEp_ZC;
    while(Sp != Ep)
    {
        *Buff = USART0_ReceiveFifo[Sp++];
        Buff++;
        Len++;
    }
    return(Len);
}

/***************************************************************************//**

*******************************************************************************/
void USART0_DeleteFifo_ZC(uint8_t Len)
{
    if(Len)
    {
        USART0_ReceiveFifoSp_ZC += Len;
    }
    else
    {
        USART0_ReceiveFifoSp_ZC = USART0_ReceiveFifoEp_ZC;
    }
}