4 Custom
LSI
The custom
LSI
is a 100-pin single chip
LSI
on which the
MZ-800
memory
controller
(110
controller) and
CRT
controller, etc. are contained.
4-1
Memory controller
Used
for
the control
of
the
memory
bank. Addressing
of
DRAM, ROM, and VRAM is conducted by selection
110
address,
$EO
-
$E6,
using OUT
or
IN
command.
1/0
Signal
Device
(1/0)
address
name
,
4-2 1/0 controller
In
this
1/0
controller is created the select signal
for
assignment
of
MZ-800 internal device.
See
Table-2
for
relation
of
internal device vs
110
address.
Function
FF
Port
B,
printer data output
FE
CPR
Z80A Port A, printer control and timer interrupt
FD
PlO
(110)
Port B control (Mode
0)
FC
Port A control (Mode
3)
F2
PSG
PSG
(0)
PSG
output
port
F1
JOY
JOYSTICK
(I)
Joystick-2
input
port
FO
Joystick-1
input
port
FO
--
(0)
Pallet
write
E6
l
--
--
(110)
Memory
bank control
EO
07
Control
port
output
06
C53
8253
(110)
Counter-2 (NOTE):
Mapped
to
E007
-
E004
in the
os
Counter-1
MZ-700 mode.
04
Counter-0
DJ
Control
02
KEY
8255
(110)
Port
C,
cassette, etc.
(NOTE):
Mapped
to
E003 -
EOOO
in the
01
Port 8, key
input
MZ-700 mode.
DO
Port A, key strobe output
CF
0
CE
110
CRTC
register
CD
--
--
0
cc
0
$E008
--
--
110
TEMP, HBLK input; and 8253
GO
ON/OFF
output
for
the MZ-700 mode only.
.,
When above 1/0 address is accessed,
it
makes IOWR active
for
OUT
or
lORD
for
IN
command.
6
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