PIC32 SPI外设在从模式下 配置为增强型缓冲模式，中断配置为fifo全满接受中断（接受为32bit模式，所以有fifo有4级深度）。我的问题是：这样是在接受4x32bit数据后进入中断，还是每接受32bit数据进入中断？如何读取4级深度fifo数据？
void SPI1_init(void)
{       
        // SPI open mode slave;
        SpiOpenFlags oflags=SPI_OPEN_MODE32|SPI_OPEN_SMP_END|SPI_OPEN_ON|SPI_OPEN_SLVEN;
        //when start the spi xmode ,the first step was disabled the interrupt
        INTEnable(INT_SPI1RX,0);              //disable spi_int
        INTClearFlag(INT_SPI1RX);
        INTClearFlag(INT_SPI1TX);
        INTClearFlag(INT_SPI1E);
        // open spi1 ,spi1set ,master mode outclk prescaler
        SpiChnOpen(1, oflags, 4);              //enable spi_1 peripheral
        SPI1CONSET = 0x0001000;           //enhaned mode
        SPI1CONSET = 0x0000003;          //fifo fil as event
        //set the spi1rx interrupt priority and subpriority
        INTSetPriority(INT_SPI1RX,3);        //set spi priority 3
        INTSetSubPriority(INT_SPI1RX,0);    // set spi subpriority 0
        //enable the spi1rx interrupt
        INTEnable(INT_SPI1RX,1);                //enable spi_int       
}