m68k SPI or QSPI drivers?

Joel Sherrill joel.sherrill at OARcorp.com
Fri Mar 23 11:50:18 UTC 2001

"Aaron J. Grier" wrote:
> On Wed, Mar 21, 2001 at 05:28:46PM -0700, "Michael P. Collins" on korat wrote:
> > I have an application for which I must operate the SPI on an MC68331
> > in slave mode.  I've used this SPI in master mode quite a lot, simply
> > polling the status register, but it looks as though I'll need to
> > enable the receiver interrupt to avoid overruns in slave mode.  Does
> > anyone know of an RTEMS driver which might exist that I can use?  One
> > for the QSPI would be ideal, but I'd expect any working SPI driver
> > would probably be good as a starting point.
> I have a very simplistic master-only QSM driver internal to my BSP
> implemented as a library, as well as a rather general GPT driver.  I'd
> move them into libcpu, but they are woefully incomplete and depend on a
> set of headers entirely separate from those in exec/score/cpu/m68k.
> the GPT and TPU don't have headers distributed with RTEMS, and as far as
> I know, there aren't any "official" motorola C headers for the 683xx
> family, so everything's kind of ad-hoc.  I wrote my headers for the
> 68331 before I even started with RTEMS, and have put them in libcpu, (I
> can provide them to anybody who's interested,) but as the '331 is the
> only member of the 683xx family I'm familiar with, I'm not sure if
> they'd integrate well with other family members, or if I'd be better off
> putting them in a 68331-specific directory.  How general do we want to
> make the include files?  should 68331, 68360, and 68302 share header
> files, for instance?
> Joel?  what's the vision for libcpu?

In an ideal world, libcpu/m68k would contain support for all the
peripheral options on the 683xx family like the QSM, TPU, etc.
Then the gen683xx BSPs would be able to share them.

That's the vision.  But the reality is that it is hard to know what is
truly portable about those HW modules from one 683xx to another.
This should make it trivial to support new 683xx CPUs even if they
are customer specific.

I would like to se the same thing happen with the PPC. :)

OAR would love to get some support from Motorola SPS to properly 
support these modules in libcpu.  

> --
>   Aaron J. Grier   |    Frye Electronics, Tigard, OR   |   aaron at frye.com

Joel Sherrill, Ph.D.             Director of Research & Development
joel at OARcorp.com                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
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