On May 8, 2009, at 9:04, Øyvind Harboe wrote: > For the sake of argument: if 16 roundtrips was the total # of > roundtrips > for a step, then I'd have to see real world numbers before I > believed that > that was observable.
If I remember the USB spec correctly, the lowest achievable round-trip time (ie. one OUT transfer followed by one IN transfer) is two milliseconds for low- and full-speed devices. This is somewhat mitigated by the fact that transfers can be pipelined so the OUT transfer overlaps the previous IN transfer, but that will require support for asynchronous transfers (so eg. pre-1.0 versions of libusb are out). Regards, Anders Montonen _______________________________________________ Openocd-development mailing list Openocd-development@lists.berlios.de https://lists.berlios.de/mailman/listinfo/openocd-development
