Customlsi - Sharp MZ-800 Service Manual

MZ-800
4-2. Custom LSI
The custom LSI is a 100-pin single chip LSI on which the
MZ-800 memory controller (I/O controller) and CRT
controller, etc. are contained.
4-2-1. Memory controller
Used for the control of the memory bank. Addressing of
DRAM, ROM, and VRAM is conducted by selection I/O
address, $EO - $E6, using OUT or IN command.
I/O Signal
Device (I/O)
address name
4-2-2. 1/0 controller
In this I/O controller is created the select signal for
assignment of MZ-800 internal device.
See Table-2 for relation of internal device vs I/O
address.
Function
FF Port B, printer data output
FE
CPR
Z80A Port A, printer control and timer interrupt
FD
PlO (I/O) 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
1
- - - -
(110)
Memory bank control
EO
D7
Control port output
D6
C53 8253 (I/O)
Counter-2 (NOTE): Mapped to E007 - E004 in the
D5
Counter-1 MZ-700 mode.
D4
Counter-O
D3 Control
D2
KEY
8255 (110)
Port C, cassette, etc. (NOTE): Mapped to E003 - EOOO in the
D1
Port B, key input MZ-700 mode.
DO Port A, key strobe output
CF 0
CE
I/O
CRTC register
CD
- -
- -
0
CC 0
$E008
- -
- -
I/O
TEMP, HBLK input; and 8253 GO ON/OFF output for the MZ-700 mode only.
*
When above I/O address is accessed, it makes 10WR active for OUT or lORD for IN command.
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