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 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
