On Thu, 16 Jan 2014, Tim Roberts wrote: > > This is where things getting complicated. Interrupt or Bulk transfers > > scheduling > > are not time guarantied and 1mS period between two packets is sometime > > bigger resulting > > in very bad synchronization (verified with oscilloscope). > > No, you are wrong. What you say is correct for bulk pipes, but the > packet timing for interrupt and isochronous pipes is IDENTICAL. The > scheduling is guaranteed, using exactly the same mechanism. If you have > an interrupt pipe with 256-byte packets and an interval of 1, you will > see EXACTLY the same results as if you had an isochronous pipe with > 256-byte packets and an interval of 1.
That's not strictly true. With isochronous transfers, an error will cause one particular piece of data to be lost, but the following pieces will still be sent at the right times. With interrupt transfers, an error will cause up to two retries, delaying not just the one piece of data but also everything following it. Of course, this usually doesn't matter. Transient transfer errors tend to be pretty rare. Alan Stern ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ libusbx-devel mailing list libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
