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ZiLOG System 8000 Hardware Reference Manual

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HRM
21
Zilog
HRM
21
/
UNIT
/
Unit
is
written
to
the
controller
through
CP1.
Any
value
between
zero
and
three
is
valid.
I
HEAD
/ Head
is
written
to
the
controller
through
CP2.
/
CYLINDER
/ The
target
cylinder
number
is
written
to
the
controller
through
command
ports
CP3
and
CP4. The
low
or~er
eight
bits
of
the
ten-bit
cylinder
address
are
issued
to
the
controller
through
CP3
and
the
high
order
two
bits
are
issued
through
CP4
bits
zero
and
one.
I
SECTOR
/ The
sector
number
of
the
sector
to
be
read
is
passed
to
the
control~er
through
the
sector
register,
CP5.
/
WORD
COUNT
/ The
number
of
words
to
read
from
the
disk
is
sent
to
the
controller
through
the
word
count
control
regis-
ter
pair,
CP8
and
cpg. A word
count
greater
than
a
single
sector
length
is
interpreted
as
a
request
for
a
multiple
sector
read.
I
ADDRESS
/ The
24-bit
address
of
the
host
data
buffer
is
passed
to
the
controller
through
a
register
triplet;
CP10,
CP11,
and
CP12.
8.4.
Write
Sector
I
UNIT
/
HEAD
/
CYLINDER
/
SECTOR
/
WORD
COUNT
/
ADDRESS/
The
Write
Sector
command
requires
both
a
disk
address·
[unit,
head,
cylinder,
sector]
and
a
host
system
buffer
address
[word
count,
address].
Less
than
one
sector
of
data
is
read
from
host
memory
if
the
word
count
is
less
than
a
sector
in
length.
The
controller
command
for
multiple
sector
writes
and
.
single
sector
writes
is
equivalent
to
the
word
count
determining
the
number
of
sectors
for
the
transfer.
/
UNIT
/
Unit
is
written
to
the
controller
through
CP1.
Any
value
between
zero
and
three
is
valid.
/
HEAD
/ Head
is
written
to
the
controller
through
CP2.
/
CYLINDER
/ The
target
cylinder
number
is
written
to
the
controller
through
command
ports
CP3
and
CP4. The
low
order
eight
bits
of
the
ten-bit
cylinder
address
are
issued
to
the
controller
through
CP3
and
the
high
order
two
bits
are
issued
through
CP4
bits
zero
and
one.
I
SECTOR
/ The
sector
number
of
the
sector
to
be
read
is
sent
to
the
controller
through
the
sector
register,
CP5.
B-2
Zilog
B-2

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ZiLOG System 8000 Specifications

General IconGeneral
BrandZiLOG
ModelSystem 8000
CategoryDesktop
LanguageEnglish

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