Herb Peyerl wrote:
> 
>  > >         0x0080          calendar of some sort
>  >
>  > This one's a bit weird; have to keep looking at it.
> 
> I don't think you're terribly interested in that calendar 'cuz there's no
> battery hooked up to it.

Hmm, so the battery on the 425 board talks to the HP clock?  Fair
enough.
 
> The "docs" that I have from the Apollo DN2500 (codenamed "frodo") and the
> "utility chip" that it has indicate effectively what you guys are seeing
> as far as layout.

Ah, now I understand why it's called the "frodo" chip. Guess I'd better
rename my driver at some stage 8)
 
> I have:
>     cpu_isr     base+0xc0   interrupt status reg
>                 bit 5     53c90 scsi interrupt.
>                 bit 4     53c90 DMA request.

I would guess that these aren't used on the 4xx...

>     cpu_ccr     base+0xd0   cpu control reg
>     diag_cr     base+0xd0   Diagnostic mode control register
>                 bit 7     fpu enable
>                 bit 6     toggle parity value when bit 5 is low
>                 bit 5     force parity error
>                 bit 4     clear parity error & buserr reg
>                 bit 3     enable 4mbit drams, hi=1mbit, lo=4mbit
>                 bit 2     disable parity error nmi.
>                 bit 1     margin power supply low
>                 bit 0     margin power supply high

Any idea if any of these at all are used?  It would appear that
the HP hardware covers some of these functions elsewhere.

>     pic         base+0xe0

No details on this one? 8(

--
Mike Smith  *BSD hack  Unix hardware collector
The question "why are the fundamental laws of nature mathematical"
invites the trivial response "because we define as fundamental those
laws which are mathematical".  Paul Davies, _The_Mind_of_God_