Motorola Powerstack Parallel Port

Jeff Rugen jrugen at
Fri May 14 14:02:45 EST 1999

On Thu, 13 May 1999, Gary Thomas wrote:

> On 13-May-99 Jeff Rugen wrote:
> > 
> > Ok, according to the book that came with my Motorola PowerStack, I have a
> > parallel port that is compatible with IEEE standard 1284, including the
> > Extended Capability Port (ECP) and Enhanced Parallel Port (EPP).  However,
> > the driver (parport_pc) doesn't recognize it as ECP and EPP, and says its
> > only SPP.  I haven't played around the parallel port much, so I figured I'd

<snip -- context above>

> > I have one of the old 100MHz 604 machines.  I'm trying to get the quickcam
> > drivers working with the 2.2.x/2.3.x kernel (I had one of the drivers
> > working with the 2.0.x kernel, but I don't know if it was in EPP or SPP
> > mode).
> > 
> > Any help, pointers, or advice on this topic would be much appreciated.
> > If you know what specific chip is used to implement the parallel
> > port, I can look around for a data book on it as well.  Thanks for any help.
> >
> The parallel port, along with most of the other devices in the system, are
> implemented in the PCI-bridge chip (82473 IIRC).

Ok, now flipping the book that came with the machine over to look at the
other page, I notice that it indicates the Paralell Port is part of the
National Semiconductor PC87303 "Super I/O" controller.  RTFM does wonders,

So I grabbed the documentation.  It looks like on reset, the parallel port
comes up in SPP mode.  I'd need to twiddle a register or two in the 87303 to
put it in either EPP or ECP mode.  Also, unlike some of the parallel ports
supported by parport_pc, the port can either be in EPP or ECP mode, but not
both (meaning only one of the two sets of additional registeres are

Now, glancing through parport_ax (the Sun Ultra/AX paralell port file), I
notice some calls to ns87303_readb() and ns87303_writeb().  I'm staring to
think that (after some tweaking), the PowerStacks may want to be using that
parallel port driver.  However, I don't know how many of them actually use
the 87303.  Is it common enough that PReP would use it, or is it specific to
a few types of machines?  Or maybe it would be a configuration option.

The include/asm-sparc64/ns87303.h file does look generic enough to fit right
into the asm-ppc directory as well.  Anyone have any ideas on the numbers,
or know the direction the arch/ppc directories are heading well enough to
know if this would be something to pursue?

Jeff Rugen                      jrugen at

..Had this been an actual emergency, we would have fled in terror, and you 
would not have been informed.

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