<s>
The	O
HD64180	B-General_Concept
is	O
a	O
Z80-based	O
embedded	B-Architecture
microprocessor	I-Architecture
developed	O
by	O
Hitachi	O
with	O
an	O
integrated	O
memory	B-General_Concept
management	I-General_Concept
unit	I-General_Concept
(	O
MMU	O
)	O
and	O
on-chip	O
peripherals	O
.	O
</s>
<s>
The	O
Hitachi	B-General_Concept
HD64180	I-General_Concept
"	O
Super	O
Z80	B-General_Concept
"	O
was	O
later	O
licensed	O
to	O
Zilog	O
and	O
sold	O
by	O
them	O
as	O
the	O
Z64180	B-General_Concept
and	O
with	O
some	O
enhancements	O
as	O
the	O
Zilog	B-Device
Z180	I-Device
.	O
</s>
<s>
The	O
HD64180	B-General_Concept
has	O
the	O
following	O
features	O
:	O
</s>
<s>
The	O
HD64180	B-General_Concept
has	O
a	O
pipelined	O
execution	O
unit	O
which	O
processes	O
most	O
instructions	O
in	O
fewer	O
clock	O
cycles	O
than	O
the	O
Z80	B-General_Concept
.	O
</s>
<s>
This	O
instruction	O
type	O
takes	O
21	O
transition	O
states	O
to	O
execute	O
per	O
iteration	O
;	O
on	O
the	O
HD64180	B-General_Concept
it	O
takes	O
14	O
t-states	O
.	O
</s>
<s>
The	O
on-chip	O
generator	O
for	O
wait	O
states	O
makes	O
it	O
possible	O
to	O
access	O
too-slow	O
hardware	O
on	O
a	O
selective	O
basis	O
using	O
a	O
device	O
filter	O
,	O
as	O
is	O
done	O
for	O
the	O
TRS-80	B-Device
Model	I-Device
4	I-Device
's	O
balky	O
keyboard	O
.	O
</s>
<s>
The	O
HD64180	B-General_Concept
will	O
not	O
execute	O
the	O
"	O
undocumented	O
"	O
Z80	B-General_Concept
instructions	O
,	O
particularly	O
the	O
ones	O
that	O
access	O
the	O
index	O
registers	O
IX	O
and	O
IY	O
as	O
8-bit	O
halves	O
.	O
</s>
<s>
The	O
Micromint	O
SB180	O
,	O
SemiDisk	O
Systems	O
DT42	O
CP/M	B-Application
computers	O
,	O
and	O
Olivetti	O
CWP	O
1	O
and	O
ETV	O
210s	O
videotypewriters	O
(	O
also	O
running	O
ROM	O
based	O
CP/M	B-Application
2.2	O
)	O
were	O
based	O
on	O
the	O
Hitachi	B-General_Concept
HD64180	I-General_Concept
.	O
</s>
<s>
The	O
XLR8er	B-Device
upgrade	O
board	O
for	O
the	O
TRS-80	B-Device
Model	I-Device
4	I-Device
also	O
used	O
it	O
.	O
</s>
<s>
On	O
the	O
Victor	O
HC-90	O
and	O
HC-95	O
MSX2	B-Operating_System
computer	O
,	O
the	O
HD64B180	O
was	O
used	O
for	O
its	O
turbo	O
mode	O
next	O
to	O
the	O
regular	O
Z80	B-General_Concept
.	O
</s>
