Peter C. Wallace wrote: > On Sun, 6 Dec 2009, Jon Elson wrote: > > >> Date: Sun, 06 Dec 2009 12:23:50 -0600 >> From: Jon Elson <el...@pico-systems.com> >> 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] What parport chipsets are working ? >> >> I have put some notes on parallel port experiences on a >> wiki page related to my products. We face the same EPP >> problems. SIIG has worked VERY well, but needs an >> antique Windows system to set up the desired port mode. >> I am amazed they don't come out with a new program. >> >> Jon >> > > I suspect the reason that the linux PP driver has troubles is related to this. > > That is, on many chips, theres no good register level setup information for > selecting different modes. > If the board follows the Microsoft-written IEEE-1284 standard, which NETMOS' (IIRC) says they do, then the setup is very standardized (although wierd). There is a config register 402 (hex) byte addresses higher than the parport data register address. You write a 0x80 to this port address to set it to EPP mode. This has worked on a number of chips that do follow the standard, such as all Dell motherboards and some other PCI boards such as with the ITE8875F chip. The old SIIG seems to only be configurable by their setup program that rewrites the EEPROM.
My diags and the hal_ppmc.c driver don't use the Linux PP driver, so that is not part of the issue. I believe the problem is the NETMOS chips just don't handle the synchronization between the CPU and the WAIT line on the EPP bus correctly. Jon ------------------------------------------------------------------------------ Join us December 9, 2009 for the Red Hat Virtual Experience, a free event focused on virtualization and cloud computing. Attend in-depth sessions from your desk. Your couch. Anywhere. http://p.sf.net/sfu/redhat-sfdev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
