Service manual
4-2-7. Register
functions
VRAM
configuration
• One
or
two
chips
of
16
KB
VRAM
are used.
•
In
the
case
of
a
single
16
KB
VRAM
chip,
it
handles
320 x 200
dots,
4
colors,
or
640 x 200
dots
1
color.
•
In
the case
of
two
16
KB
VRAM
chips,
it
handles
320
x 200 dots, 16
colors,
640 x 200
dots,
4
colors,
320 x
200 dots, 4
colors,
2
frames,
or
640 x 200
dots,
1
color,
two
frames.
* Discussed
next
are
about
functions
of
the
custom
LSI.
There
may
be
some
restrictions
because
the
standard
version
of
the
MZ-800
incorporates
only
one
16
KB
RAM.
Display
mode
register
(OUT
&HCE)
• It consists
of
four
bits
which
are used
to
represent
display
method,
resolution,
and
display
screen
(color
plane) in
combined
way.
Display
mode
register
(DMD)
MZ-800
•
DMD
3, 2:
Display
method
and
resolution
DMD
3
o
2
o
Bit map, 320 x 200
o I 1 I Bit map,
64~~
_____
_
1
-i
0 I MZ-700
mode
-----~--
----------------+------------------------~~-----
1 1 I Prohibited
•
DMD
1, 0:
Display
screen
designation
DMD DMD
320 x 200
640
x 200
I
MZ-700
1
0
-~=
0 0
Frame A, Planes I and n
Frame A, Plane I Normal
0 1
Frame
B,
Planes
ID
and
IV
Frame
B,
Plane
ID
(NOTE)
Prohibited
1
0
Planes
I,
n,
m,
and
IV
Planes
I,
m I Prohibited
1 1 Prohibited
NOTE: 640 x 200, Plane B IS Plane
m,
not
Plane
n.
• With the MZ-800, DMD 1
~
0,
DMD
0 =
O.
Table-'
VRAM
configuration
and
display
mode
VRAM
I
Display Display
Color
combination
DMD
VRAM configuration
Resolution
~:~~c~
_________
~
___
..
~_~______
i 0010'
'"me
(NOTEI
_ _ 3 2
__
'I
0
_I
:
ItIVTI'
1
320
x 200
140010<5,
F"mJ
I. n I 0 0 1 0 I 0
16
KB
8000
H
f----
~
___
~_B_F_F_F
-VA-0--7
--vc-o-.,
-----llltl I
F"me
+ n
l~
-
~o
1~+-;
""'"
I I
11
j
r-Ll
320 x 200
140010<5
(eme
B 1
rn,
;---1
~-i
-~
l 0
+r~-
H G G G
-t-------+--~t-
--
---
32
KB
__
-=-~
"
on
"
1'6
0010<5
I
F"me
~I.
~~-f
I 0
_1_'
r
T'
vcr
~010'
l:am~-____f--~---1-l-~~---~-
8000 0 G
t
640 x 200 i
I-~ame
B I
ill
I 0 i 1 I 0
i,l
1
[ 1 i I ! i
I III I 1-------- I ---1---1-----+----
I I I I
BFFF
+.1.
4 colors Frame A I I.
ill
i 0 i 1 i 1 i 0
!
+----:-
I ! I :
~-~--
--------------~~---------~
I
~0-2-c5-h-~r-nae-cs-te-r-s-t-II-8
0010<5
!"me A I
AGB
I,
fo
T~
i;-
640 x
200
(NOTE)
Except
for
the MZ-700 mode, actual display colors are produced by the pallet.
20