Chris McClelland wrote: > The EP2&6 pair seems to require quad-buffering in order to get the best > throughput (I measure 43MiB/s when quad-buffered and about 33MiB/s when > double-buffered),...
Yes. You should also be aware that those speeds are highly dependent on the quality of the host controller, and the other devices on the bus. We, also, have sustained 45 MB/s through an FX2 bulk pipe, but only on certain host controllers. The same hardware in another machine won't push beyond about 30 MB/s. And bulk transfers, of course, are last priority, and compete for bandwidth equally amongst themselves. If you have a USB keyboard or mouse or speakers or camera, all of those get their pieces first. As long as your buffering can handle that, you're fine, but it's dangerous to make assumptions about bulk throughput... > Since the JTAG streams are limited by the speed of the 8051, keeping the > send/receive chunks down to 64 bytes is perfectly fine, and possible > because I control the code on both sides. Yes. It is easy to forget how abysmally slow the FX2's 8051 is. At best, you get 3 MIPS. -- Tim Roberts, t...@probo.com Providenza & Boekelheide, Inc. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ libusbx-devel mailing list libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
