Subject: Re: more on the 400-series utility chip
To: Jason Thorpe <>
From: mike smith <>
List: port-hp300
Date: 03/21/1997 19:49:01
Jason Thorpe wrote:
> We have the following items (offsets from util chip base)
>         0x0080          calendar of some sort

This one's a bit weird; have to keep looking at it.

>         0x00d0          diagnostic control register


>         0x00e0          isa pic
> Now, bits in the isa interrupt status register (appears to be a single byte):
>         0x01            off if service switch is set to "service"
>         0x02            on if interrupt on isa IRQ 3, 4, 5, or 6
>         0x04            on if interrupt on isa IRQ 7, 9, 10, or 11
>         0x08            on if interrupt on isa IRQ 12, 14, or 15

Hmm I wonder if that goes along with the information I already have on
'isa pic' register, ie. the lower bits in the pic register would mask
ISA interrupts, and the higher bits in the status register correspond to
the apci ports?

> I have some more random notes about where ISA lives and how the i/o
> space is encoded... I'll hunt for them.

Magic!  Thanks!
> Jason R. Thorpe                             

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_