<s>
Autoconfig	B-Device
is	O
an	O
auto-configuration	B-Device
protocol	O
of	O
Amiga	B-Device
computers	I-Device
which	O
is	O
intended	O
to	O
automatically	O
assign	O
resources	O
to	O
expansion	O
devices	O
without	O
the	O
need	O
for	O
jumper	B-Device
settings	O
.	O
</s>
<s>
It	O
is	O
analogous	O
to	O
PCI	B-Architecture
configuration	I-Architecture
through	O
ACPI	B-Device
.	O
</s>
<s>
Autoconfig	B-Device
is	O
integrated	O
within	O
the	O
Amiga	B-Device
's	O
Kickstart	B-Device
firmware	O
,	O
usually	O
stored	O
in	O
ROM	B-Device
.	O
</s>
<s>
When	O
the	O
system	O
is	O
switched	O
on	O
,	O
AmigaOS	B-Application
interrogates	O
each	O
expansion	O
device	O
in	O
turn	O
and	O
assigns	O
address	O
space	O
or	O
resources	O
as	O
needed	O
.	O
</s>
<s>
Through	O
Autoconfig	B-Device
the	O
OS	O
can	O
access	O
firmware	O
on	O
expansion	O
devices	O
,	O
for	O
example	O
,	O
to	O
boot	O
from	O
a	O
disk	O
connected	O
to	O
a	O
hard	O
disk	O
controller	O
.	O
</s>
<s>
Expansion	O
devices	O
respond	O
to	O
certain	O
fixed	O
memory	O
addresses	O
starting	O
at	O
hexadecimal	O
(	O
or	O
for	O
Zorro	B-Device
III	I-Device
)	O
if	O
the	O
/CFGIN	O
signal	O
is	O
asserted	O
and	O
the	O
device	O
is	O
not	O
already	O
configured	O
.	O
</s>
<s>
The	O
CPU	B-General_Concept
reads	O
nibbles	O
of	O
configuration	O
information	O
(	O
usually	O
supplied	O
by	O
a	O
PAL	O
)	O
such	O
as	O
manufacturer	O
ID	O
,	O
product	O
ID	O
,	O
and	O
the	O
amount	O
of	O
address	O
space	O
the	O
device	O
requires	O
.	O
</s>
<s>
The	O
CPU	B-General_Concept
then	O
writes	O
a	O
base	O
memory	O
address	O
to	O
the	O
device	O
(	O
or	O
tells	O
it	O
to	O
"	O
shut	O
up	O
"	O
if	O
for	O
some	O
reason	O
it	O
ca	O
n't	O
be	O
configured	O
)	O
,	O
and	O
the	O
device	O
asserts	O
/CFGOUT	O
.	O
</s>
<s>
In	O
a	O
backplane	B-Architecture
design	O
such	O
as	O
the	O
Amiga	B-Device
2000	I-Device
,	O
connecting	O
the	O
/CFGOUT	O
of	O
one	O
slot	O
directly	O
to	O
the	O
/CFGIN	O
of	O
the	O
next	O
would	O
create	O
the	O
problem	O
that	O
an	O
unoccupied	O
slot	O
would	O
break	O
the	O
configuration	O
chain	O
.	O
</s>
<s>
To	O
solve	O
this	O
,	O
the	O
backplane	B-Architecture
ORs	O
the	O
/CFGIN	O
and	O
/CFGOUT	O
signals	O
to	O
form	O
the	O
/CFGIN	O
for	O
the	O
next	O
slot	O
(	O
/CFGOUT	O
is	O
pulled	O
low	O
if	O
undriven	O
)	O
,	O
which	O
allows	O
empty	O
slots	O
to	O
be	O
bypassed	O
.	O
</s>
<s>
This	O
requires	O
one	O
74LS32	O
(	O
quad	O
OR	O
gate	O
)	O
on	O
the	O
Amiga	B-Device
2000	I-Device
,	O
which	O
is	O
the	O
only	O
motherboard	B-Device
hardware	O
required	O
by	O
Autoconfig	B-Device
.	O
</s>
<s>
Autoconfig	B-Device
is	O
part	O
of	O
the	O
Zorro	B-Device
II	I-Device
and	O
Zorro	B-Device
III	I-Device
expansion	O
bus	O
specification	O
for	O
configuring	O
expansion	O
devices	O
in	O
Amiga	B-Device
systems	O
.	O
</s>
<s>
Zorro	B-Device
II	I-Device
was	O
first	O
used	O
in	O
the	O
Amiga	B-Device
2000	I-Device
,	O
though	O
a	O
similar	O
expansion	O
bus	O
is	O
present	O
on	O
the	O
Amiga	B-Device
1000	I-Device
.	O
</s>
<s>
Zorro	B-Device
II	I-Device
is	O
a	O
relatively	O
straightforward	O
extension	O
of	O
the	O
68000	B-Device
bus	O
.	O
</s>
<s>
Autoconfig	B-Device
requires	O
the	O
68000	B-Device
data	O
and	O
address	O
bus	O
to	O
be	O
available	O
to	O
all	O
devices	O
on	O
the	O
bus	O
.	O
</s>
<s>
In	O
theory	O
,	O
a	O
virtual	O
address	O
system	O
,	O
as	O
used	O
in	O
PCI	B-Protocol
,	O
would	O
require	O
a	O
minor	O
revision	O
to	O
Autoconfig	B-Device
.	O
</s>
<s>
The	O
Amiga	B-Device
2000	I-Device
can	O
accommodate	O
five	O
Zorro	O
expansion	O
cards	O
,	O
such	O
as	O
,	O
RAM	O
expansions	O
,	O
SCSI	O
controllers	O
and	O
graphic	O
cards	O
.	O
</s>
<s>
In	O
the	O
A2000	O
,	O
two	O
Zorro	B-Device
II	I-Device
slots	O
are	O
aligned	O
with	O
ISA	B-Architecture
slots	I-Architecture
.	O
</s>
<s>
The	O
Zorro	O
bus	O
and	O
ISA	B-Architecture
bus	I-Architecture
can	O
be	O
connected	O
by	O
means	O
of	O
a	O
"	O
bridgeboard	O
"	O
,	O
such	O
as	O
,	O
the	O
Janus	O
Hardware	O
Emulator	O
,	O
which	O
allows	O
emulation	O
of	O
Intel	B-General_Concept
80286	I-General_Concept
or	O
80386	B-General_Concept
systems	O
.	O
</s>
<s>
Zorro	B-Device
III	I-Device
is	O
the	O
32	O
bit	O
auto-configuring	O
expansion	O
bus	O
of	O
Amiga	B-Device
3000	I-Device
and	O
Amiga	B-Device
4000	I-Device
systems	O
.	O
</s>
<s>
From	O
the	O
A3000	O
design	O
onwards	O
,	O
it	O
was	O
deemed	O
desirable	O
for	O
all	O
enumerable	O
hardware	O
expansions	O
to	O
use	O
Autoconfig	B-Device
.	O
</s>
<s>
It	O
is	O
OS-legal	O
for	O
non-Autoconfig	O
hardware	O
to	O
be	O
completely	O
ignored	O
and	O
the	O
standard	O
was	O
adopted	O
in	O
AmigaOS	B-Application
3.1	O
.	O
</s>
<s>
In	O
early	O
Commodore	O
documents	O
it	O
was	O
styled	O
Auto	O
Configuration	O
,	O
auto-config	O
or	O
AutoConfig	B-Device
,	O
whereas	O
in	O
later	O
documents	O
it	O
was	O
styled	O
AUTOCONFIG	B-Device
.	O
</s>
