<s>
The	O
Acorn	B-Device
System	I-Device
1	I-Device
,	O
initially	O
called	O
the	O
Acorn	B-Device
Microcomputer	I-Device
(	O
Micro-Computer	B-Architecture
)	O
,	O
was	O
an	O
early	O
8-bit	O
microcomputer	B-Architecture
for	O
hobbyists	O
,	O
based	O
on	O
the	O
MOS	B-General_Concept
6502	I-General_Concept
CPU	B-General_Concept
,	O
and	O
produced	O
by	O
British	O
company	O
Acorn	O
Computers	O
from	O
1979	O
.	O
</s>
<s>
The	O
main	O
parts	O
of	O
the	O
system	O
were	O
designed	O
by	O
then-Cambridge-undergraduate	O
student	O
Sophie	O
Wilson	O
,	O
with	O
a	O
cassette	B-Device
interface	O
designed	O
by	O
Steve	O
Furber	O
.	O
</s>
<s>
Top	O
Row	O
:	O
INS8154	O
RAMIO	O
Integrated	O
Circuit	O
(	O
for	O
keyboard	O
and	O
display	O
)	O
,	O
6502	B-General_Concept
CPU	B-General_Concept
,	O
2	O
×	O
2114	O
1024×4	O
RAM	B-Architecture
,	O
2	O
×	O
74S571	O
512×4	O
PROM	B-Device
,	O
RAM/ROM	O
expansion	O
socket	O
,	O
second	O
INS8154	O
for	O
peripheral	O
expansion	O
(	O
optional	O
extra	O
with	O
the	O
kit	O
version	O
)	O
.	O
</s>
<s>
Bottom	O
row	O
:	O
1MHz	O
clock	O
crystal	O
,	O
4	O
×	O
TTL	B-General_Concept
logic	I-General_Concept
chips	O
providing	O
address	O
decoding	O
for	O
the	O
memory	O
and	O
I/O	B-General_Concept
expansion	O
,	O
5V	O
regulator	O
.	O
</s>
<s>
The	O
smaller	O
empty	O
socket	O
in	O
the	O
middle	O
of	O
the	O
board	O
was	O
used	O
to	O
set	O
the	O
memory	O
map	O
of	O
the	O
RAM	B-Architecture
,	O
ROM	B-Device
and	O
I/O	B-General_Concept
expansion	O
by	O
fitting	O
or	O
soldering	O
wires	O
between	O
various	O
positions	O
according	O
to	O
the	O
instructions	O
in	O
the	O
Acorn	B-Device
System	I-Device
1	I-Device
Technical	O
Manual	O
.	O
</s>
<s>
Almost	O
all	O
CPU	B-General_Concept
signals	O
were	O
accessible	O
via	O
the	O
standard	O
Eurocard	O
connector	O
on	O
the	O
right-hand	O
side	O
of	O
the	O
board	O
.	O
</s>
