duke43j;616181 Wrote: > I think that is the way the Wavelength DAC works using a USB interface. > From reading the literature, it sounds like it controls the flow of > data by sending NAKs (not acknowledge) back to the source which > effectively tells the source to retransmit the data (thereby slowing > down the data stream). This approach should work, but it sounds a > little clumsy. Do I understand this correctly? Does anybody have > another understanding of how async USB works?
Async USB does NOT use handshaking. Its the same as adaptive in most ways, the host sends out a continuous stream, the difference is that the receiver can tell the host to slow down or speed up the rate at which it sends the data. In both adaptive and asynch the data from the USB receiver goes into a buffer and gets read out by a local clock. A circuit keeps track of how full the buffer is, if it starts getting too full or too empty the circuit makes a change, for adaptive it speeds up or slows down the local clock, in async it sends a commnd back to the host to speed up or slow down the data rate. In either case data is NEVER resent, there is no error correction. Interestingly enough there IS error detection, but no way to do anything about it! Data errors are extremely rare so this is not particularly an issue. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=84903 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
