关于Slave FIFO的问题

嗨，在我设计的FIFO同步填充在两6mbs，流媒体数据来自和ADC，用胶水逻辑关系（这是和软件无线电的应用）。如果我使用同步端点大小的1024包和1包每微帧，带宽约为8mbs。由于USB端比FIFO更快，这意味着（如果我理解正确的话，我是新来的，一些USB）令牌将抵达时，没有数据已提交但。在这种情况下会发生什么？主机将等待或发送一个零包长度？
我可以缩短同步报文长度相匹配的带宽，750 6mbs大小包了，但我的理解是，最好是有一个更快的USB端，为了避免全FIFO的事件和数据丢失（没有其他缓冲区之间）。我说的对吗？
最后一个问题：当FIFO从全空和旗帜去断言，这是标志变化同步或异步发生ifclk可以吗？
谢谢



     以下为原文
  Hi, in my design the FIFO is synchronously filled at aobut 6MBs, with streaming data coming from and ADC, with some glue logic in between (it's and SDR application). If I use isochronous endpoint with 1024 size packet and 1 packet per microframe, the bandwidth is roughly 8MBs. Since the USB side is faster than the FIFO side, it means (if I understood correctly, i'm new to USB) that some IN tokens will arrive when no data has been committed yet. What happens in this case? The host will wait or a zero packet length will be sent?
    I could shorten the isochronous packet length to match the bandwidths, 750 size packet gives 6MBs, but my understanding is that it is better to have a faster USB side, in order to avoid full FIFO event and loss of data (there is no other buffer in between). Am I correct?
    One last question: when the FIFO goes from full to empty and the flag is de-asserted, is this flag change synchronous with IFCLK or it can happen asynchronously?
    Thanks