Hi Przemek, Am 30.05.2013 um 06:05 schrieb Przemek Klosowski <[email protected]>:
> On Wed, May 29, 2013 at 7:22 AM, Charles Steinkuehler < > [email protected]> wrote: > >> The PRU can do a great job with step/dir generation. Anything that >> has encoders should really be running with FPGA hardware and something >> like the Mesa boards. >> > > Why do you say so? PRU is running at 200MHz and can read and write GPIO > every 5ns. I think that's close to what the FPGA is capable of. Of course > FPGA can then process these in parallel using independent hardware units, > but still. The 5ns is 'on paper'; since there's more involved than a CPU cycle - the bit takes a bit of time to work through to/from the pin , the actual figures are slower Charles has done the mother of all homework on this, see here: http://tinyurl.com/oql9uqo (from what I've seen so far, that's the most thorough assessment of PRU I/O timing outside of TI ;) that said, I still think encoder inputs are entirely possible with higher rates than the soft encoder; not that I think this will be the prevalent scenario for the BB's as for FPGA-based I/O, the floodgates for all sorts of combinations are open at the low end as well: http://tinyurl.com/pm524v7 http://specialcomp.com/beaglebone/BeagleBone_FPGA.html http://ebrombaugh.studionebula.com/embedded/bcc/index.html -m > > >> I was just trying to point out that ARM parts and boards are available >> that more directly compete with the "traditional" Atom motherboards >> currently popular here (including conventional PCI/PCIe expansion slots!). >> > > As far as I can see, PCI/PCIe is the only differentiating factor, unless > you imply that Atom-class means better quality, or better noise immunity > etc. Low power should not be a big deal---after all, LinuxCNC is likely to > drive electric motors rated in kiloWatts. > ------------------------------------------------------------------------------ > Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET > Get 100% visibility into your production application - at no cost. > Code-level diagnostics for performance bottlenecks with <2% overhead > Download for free and get started troubleshooting in minutes. > http://p.sf.net/sfu/appdyn_d2d_ap1 > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with <2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
