Subject: more on the 400-series utility chip
To: None <port-hp300@NetBSD.ORG>
From: Jason Thorpe <>
List: port-hp300
Date: 03/20/1997 19:26:09

We have the following items (offsets from util chip base)

	0x0000		sio0
	0x0020		sio1
	0x0040		sio2
	0x0060		sio3
	0x0080		calendar of some sort
	0x00a0		timer
	0x00c0		isa interrupt status reg
	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

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

Jason R. Thorpe                             
NASA Ames Research Center                               Home: 408.866.1912
NAS: M/S 258-6                                          Work: 415.604.0935
Moffett Field, CA 94035                                Pager: 415.428.6939