John Kasunich wrote: > > 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. > Yes, that's certainly a major reason the hal_ppmc.c driver is set up the way it is. > HAL (and EMC2) uses Rate Monotonic Scheduling > (http://en.wikipedia.org/wiki/Rate_Monotonic_Scheduling) which is the > simplest way to guarantee meeting realtime schedules and avoid > deadlocks. However, you simply _cannot_ share a resource between > threads. Changing the scheduling/priority algorithms is not something > to be done lightly. > > I think it is perfectly reasonable for those who are using the EPP bus > to have to live with GPIO accesses in the servo thread only. > One way out of this would be to have this GPIO on a separate EPP port (unless the GPIO hardware is the same as the motion hardware).
Two separate EPP ports should be quite independent of each other. Jon ------------------------------------------------------------------------- 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
