On Sat, 9 Aug 2008, John Kasunich wrote: > Date: Sat, 09 Aug 2008 23:59:48 -0400 > From: John Kasunich <[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] Stepper configuration SNIP--------------------------------------------------------------- > The simple fact is that the EPP bus is NOT shareable between realtime > threads. That is only one of the reasons why (in my humble opinion) the > PCI based 5i2x family is so much better than the EPP based 7i43 family.
Its probably possible to make the EPP bus transactions shareable with a little bit of hardware (simple EPP hardware context save and restore, maybe triggered via a magic address cycle), but these would add even more slow EPP cycles to the preempting thread, lowering overall performance. Better to leave EPP peripherals running at the servo thread (and use the Stepgen/PWM/Quadcount/SPI hardware where speed is an issue). For PCI (and PCIe) where all I/O is atomic and separate hardware modules are truly independent, separate thread access to the GPIO is an advantage that should not be thrown away (I think I'm repeating myself... time to hit the sack) > Regards, > > John Kasunich > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > 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. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
