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Sharp MZ-5500 Tehnical Manual

Sharp MZ-5500
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HZ1D13
HZ1D14
MZ1D18
Others
DOT
CK
10.74
7.16
2xCCLK
2.68
1.79
Unit:
MHz
15-2.
Use
of
video
display
circuit
(software
control)
i)
Video
RJ.M
To
make
data
displayed
on
the
video
screen,
each
independent
dot
has
to
be
written
in
the
video
RAM.
A
single
bit
of
the
video
RAM
corresponds
to
one
bit
position
on
the
display
screen.
From
what
location
of
the
vi.deo
RAM
has
to
be
started
to
display
can
be
specified
in
unit
of
word
using
the
GDC~
and
window
controller
setup.
Sixteen
bits
of
the
bit
0
to
the
bit
15
of
the
word
will
be
displayed
from
left
to
right
in
their
order.
Fig.l5-l
·
shows
th
e memory map
of
the
video
RAM.
The
CPU
accesses
in
unit
of
one
byte
·
(8
bits)
and
one
word
(16
bits),
and
the
GDC
accesses
in
unit
of
one
word
(16
bits).
As
many
IOCS
modules
are
provided
for
displaying,
refer
to
S
ec
tion
Three,
Software,
for
more
details.
It
is
recommended
to
use
the
IOCS*
wh
en
programming
by
the
machine
language.
NOTE-1
:
Tne
display
address
is
set
'
by
the
SCROLL
command
of
the
GDC
and
VMA
of
the
WOC.
Only
the
low
otder
15
bits
of
the
address
(GDC)
are
uecoded
by
the
hardware
to
read
three
data
for
displaying
from
planes,
0,
1,
and
2.
Which
data
should
be
read
is
directed
by
VDS
of
the
WDC.
However,
giving
the
address,
30000H - 3FFFFH
(GDC)
,
for
the
display
address
may
cause
the
display
to
distort.
NOTE-2:
When
the
CPU
accesses
the
expansion
VRAM
area
of
C8000H - CFFFFH, D8000H -
DFFFFH, E8000H - EFFFFH,
NMI
will
not
be
applied
to
the
CPU
even
if
the
expansion
VRAH'
does
not
exist.
(Normally,
NMI
is
automatically
applied
if
XA
CK
is
not
returned.
However,
for
the
expansion
VRAM,
XACK
is
returned
fro
m
the
HI
chip
(CRT
controller
LSI)
even
if
the
VRAM
does
not
exist.)
NOTE-3 :
DMA
i8
not
permitted
for
the
VRAM
area
of
.
COOOOH
- EFFFFH,
so
that,
it
is
not
possible
to
make
direct
loading
and
saving
from
the
·
floppy
disk
to
the
VRAM.
And, do
not
set
the
VRAM
area
OCH,
ODH,
emd
OEH
in
the
high
order
4
bi
ts
of
the
DMA,
as
i t may
cause
the
VRAM
to
be
af
f
ec
ted
or
result
in
malfur:ction.
jj)
GDC
(~PD7220)
Since
the
GDC
is
used
for
the
CRT
controller,
·
horizontal
sync
and
vertical
sync
are
generated
from
the
GDC.
Table
15-3
shows
the
list
of
parameters
of
the
SYNC
command
of
the
GDC.
The
value
set
i.n
the
1/0
port
of
the
address
130H
is
also
contained
in
the
table.
See
Table
15-4
for
others.
Also,
see
NEC
~PD7220
GDC
User's
Manual
for
the
detail
of
the
GDC.
Summary
is
attached
at
the
end
of
this
text.

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Sharp MZ-5500 Specifications

General IconGeneral
BrandSharp
ModelMZ-5500
CategoryDesktop
LanguageEnglish

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