On Tuesday 17 October 2017 13:02:09 Chris Albertson wrote: > On the Pi the Ethernet and USB are on the same shared bus. But > how much bandwidth is required to drive a Mesa FPGA card? I > have read the Ethernet port can only push about 40% of it's spec'd > bandwidth but the card only requires 2% it's OK. > The gpio is NOT on the usb bus. So all of my extra stuff I've carved into the sheldon's config, jog dials etc, A: runs in a 100hz thread because its more complex than a normal hal file, and B: does not have to go thru the usb bus, and it runs flawlessly, no missed events ever. It just works.
The problem in ethernet is its variable latency and TCP's encoding/decoding overhead. This is what the spi bus bypasses, it all runs on the gpio pins. Only 4 for a minimum setup. The pi is sending, at 1 millisecond intervals, several 32 bit packets (up to 4 I believe, or 16 bytes, at 41 megabaud, and receiving as much data back at 25 megabaud. And that doesn't seem to make it breath hard either. > If performance is the goal you's spend an eatery $50 and buy an > Intel PC mainboard rather than the Pi. And except for the atoms, heat the shop with them. > > On Tue, Oct 17, 2017 at 9:56 AM, andy pugh <bodge...@gmail.com> wrote: > > On 17 October 2017 at 17:51, Greg Bentzinger <skullwo...@yahoo.com> wrote: > > > Using > > > these boards Ethernet port as a dedicated port is an option, > > > > I don't think it is. I have heard that the Pi Ethernet port is on > > the USB bus. > > > > -- > > atp > > "A motorcycle is a bicycle with a pandemonium attachment and is > > designed for the especial use of mechanical geniuses, daredevils and > > lunatics." > > — George Fitch, Atlanta Constitution Newspaper, 1916 > > > > ------------------------------------------------------------ > > ------------------ > > Check out the vibrant tech community on one of the world's most > > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
