On Thu, 15 Feb 2007, John Prentice wrote: > Date: Thu, 15 Feb 2007 19:07:44 -0000 > From: John Prentice <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Hardware step generator for 5I20 > > Hi > > From: <[EMAIL PROTECTED]> >> "Peter C. Wallace" <[EMAIL PROTECTED]> wrote: >> >> >> On the step/dir side: some drives require setup and/or hold times for the >> dir line with respect to the step line. Others have minumum step pulse >> lengths. Do the generators support this? Min pulse length isn't that >> hard, >> but setup and hold time can be a pain. >> >> Example: You were running along at +10 steps/sec, then you switch to -10 >> steps/sec. 99.999% of the time that is fine. But if you make the change >> a microsecond after the DDS has generated an "up" step, it will want to >> generate a "down" step a microsecond later. (The DDS accumulator will >> have only added a tiny amount, so once you switch directions, it will only >> have to subtract a tiny amount.) The HAL software stepgen has more code >> (crufty code at that) to ensure setup and hold times than is required for >> the DDS itself. > > You probably have this in hand but I grappled with it a while ago. The > project never got into production but I did lots of 'scope tests and I think > the module works properly in the file at: > > www.castlewoodconsultants.com/Misc/PulseGen.v > > It has a simple pulse generator and a ShapeSetupHold module that enforces > times defined in two registers. > > HTH
Thanks, looks about like what I was imagining and probably some things I missed... > > John Prentice > > > > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
