-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 12/26/2012 6:33 PM, Kent A. Reed wrote: > On 12/25/2012 8:14 PM, Charles Steinkuehler wrote: >> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 >> >> Happy Holidays! >> >> Now that the hm2_pci driver works in user-space, and the >> Christmas turkey is cooked (and eaten!), I've managed to absorb >> enough details to write some code for the BeagleBone PRU and >> perform some initial timing tests. >> >> As things stand now, I expect to be able to implement a >> general-purpose PRU solution that can implement step/dir, >> up/down, pwm (or delta-sigma modulation), and anything else >> anyone wants to code up for all available PRU pins (14 PRU0 pins >> available on the 'bone) that can run with a cycle time of around >> 5 uS or less (ie: 5000 nS base period with virtually zero latency >> jitter, in LinuxCNC software stepgen terms). >> >> Even better, if you simplify the task, fold common channel >> control values together (step length, dir setup/hold, etc), and >> keep state data in registers, I think it should be possible to >> implement a 3D printer (or generic 4-axis CNC + 2 PWM) in a 1 uS >> thread. And there are still dedicated hardware timers and >> encoder inputs available as well! >> >> Of course, the proof is in the pudding, so keep an eye out on >> Michael Haberler's git repo...I'll commit code there once it does >> something useful. >> >> Oh, and Michael: Thanks for the PRU tools! The "debugger" may >> be limited, but it's *WAY* better than nothing! >> >> - -- Charles Steinkuehler >> > Charles: > > I'm surprised not to see responses already but maybe everyone else > has been as preoccupied as I have been.
I figure part is the holidays, but I've always received a cool reception to "neat new idea" from this crowd. I get it...it's not real until it works, and even then it needs some real-world miles on it before most folks would consider moving big iron with it. But for some reason that defies rational, I'm committed to making this work. Oh, and thanks for the feedback! I do talk to myself a lot, but it's nice to occasionally be able to pretend someone else is listening! :) Aside: Hmm...funny how "big iron" means something different here (large chunks of moving metal that could cause significant bodily harm) vs. what I'm more normally used to (probably a s or z series mainframe). :) > A BeagleBone arrived here on Monday so I'm all set to sample your > tasty "pudding" :-) Well, it's coming along, but I don't have anything that's quite ready to run step/dir. I may go ahead and check in some code if you want to play...and at the very least I could throw some info on a wiki page so you don't have to spend a couple days learning how Michael's PRU stuff works like I did. > My 12-year old grandson's favorite word for things that impress him > is "epic." I think what you have outlined is epic. If it turns out > it's possible only to deliver half as much performance it would be > semi-epic, which is still awesome in my book!. Well, the PRUs are pretty capable, but TI is hiding some of the fancy bits (including some instructions that would be *VERY* handy for a super-fast 3D-printer/basic-CNC stepgen thread). And it doesn't help that the PRU is kind of a wacky architecture. Not that I don't like wacky (I've done commercial development in Forth for crying out loud!), but it takes a bit to warp my thought process into the available assembly command space. What I really need is several uninterrupted hours to code, but with the kids off school for holiday break, that coudl be a while! :) - -- Charles Steinkuehler [email protected] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAlDbq/cACgkQLywbqEHdNFzeHQCfUIpvdFsmmOn7U5pFZ7/9doNA YIIAn014vrzqlyW4cLEFld6oTgRGcHZr =sTmv -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnmore_122712 _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
