Printronix P9012, Руководство по обслуживанию

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2–20 Principles of Operation
CLOCK
GENERATION
6/3 MHZ
RESET
GENERATION
750 ms
CLK
NRST
6MHZ
RESET
CLK
ADDR
Z–80
CPU
DATA
CNTL
(8)
ADDRESS
DECODE
CNTLS
DECODE
AND
BUFFER
Z–80 CTC
(16)
RD
WR
INTA
EPROM
36K X 8
3MHZ
BUFFERED ADDRESS BUS
BUFFERED DATA BUS
(8)
(16)
!/O AND
MCU / DCU
COMMAND PORT
4 X 8 MCU/R: DCU/W
DIP SWITCH
HAMMER
DRIVER
TEST PORT
HAMMER
DRIVER
STATUS PORT
COLOR
CONTROL
PORT
(4)
(4)
H
A
M
M
E
R
D
R
I
V
E
R
I/O
(4)
(4)
4 X 8 DCU/R: MCU/W
BD0–7
BD0–7
D4–7
BD0–3
D0–7
D
0
–7
N/A
8254
8254
TIMER
TIMER
A0, A1
A0, A1
A0, A1
CS
CS
CS
NUD/HRS
DCMOD
HAM
DCU
I/F
COM
HSC
B
U
F
F
E
R
E
D
D
A
T
A
B
U
S
D
0
–7
B
U
F
F
E
R
E
D
A
D
D
R
S
S
E
B
U
S
D0–7
FIRE 0,1,2
MCU REC
Figure 2–15. Mechanism Control Unit (MCU) Block Diagram (1 of 2)