Experimental Physics and
Industrial Control System

Bill Brown <[email protected]> · Mon, 29 Mar 1999 08:14:21 -0800

Andrew Johnson wrote:
> 

> Some of Jeff's changes to drvIpac resolve this for both endian models; as
> long as you access the registers on the module using word rather than byte
> read/writes then the endian issue is handled completely by the hardware.

I don't see "how to get there from here,"  but I'm just now starting to
deal
with the "endian" issues.  I got all "wound around the axle" dealing
with
configuration issues - it turns out that the bsp for the Motorola mcp750
has
a major restriction on the amount of cPCI memory address space
available.

I understand that WRS is doing a re-write of the bsp.  We looked at
using
cpu (from V*I Comp.) but decided to stick with Motorola after we
discovered
that GreenSpring could modify the carriers to request much less address
space.  We have two of our carriers modified, and the mcp750 bsp seems
to
take care of "plug and play" configuration just fine.

I just received yet another set of updates from WRS which may solve the
confuguration problem, but I've got to get something working right now.

> Thus within drvIpac.h the prom structure has been redefined to use short
> integers (16 bits).  The drvIpac.c code is also changed so the upper byte
> of these values is discarded, and I'm thinking about making parallel
> changes to my drvTip810 CANbus module driver.  IMHO this is the way to
> solve the problem as the same code works for both CPU types without having
> to know what kind of CPU you're using.  It may be that this method can't
> be used for all I/O modules, so I'm open to argument about this.
> 
> The updated support will be included with Verion 2.1 of the ipac software.
> The latest release of Version 2.0, full documentation and some earlier
> releases are now available at
>         http://epics.aps.anl.gov/asd/people/anj

Since I'm in the process of doing a driver for the cPCI-200 carrier,
could I
get the new version of this stuff now?  If somebody has worked out a
solution,
I'd just as soon use it, rather than build in a kluge, only to have to
redo
everything in the not-to-distant future.

Disclaimer:  Any opinions are my own and have	  | -bill
  nothing to do with the official policy or the   |  [email protected]
  management of L.B.N.L, who probably couldn't    |  Berkeley, CA
  care less about employees who play with trains. |  aka
[email protected]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System