Printronix P9012 Maintenance Manual page 35

NVRAM
2K x 8
STATUS
OE
REGISTER
B P N N
U R D O
F I C H
C N D O
L T S S
R R T
H
W
E
R
A
D
S
E
L
E
C
T
NLOAD
ADDRESS
OUTPUT
DOT
PLUCKER
MEMORY
CONTRLR
DRAM
256K X 16
Figure 2–13. Data Control Unit (DCU) Block Diagram (2 of 2)
Principles of Operation
ADDRESS BUS
(23)
DATA BUS
(16)
FRONT
PANEL
I/F
LOGIC
NSWITCH
ADDRESSABLE
LATCHES
MISC.
CONTROL
SIGNALS
A0, A1
(8)
S/P – P/S
SHIFT REGISTER
PDATA
NPFAULT
REGSEL
NENABLE
NSWITCH
NPCLK
NPLOAD
HAMMER DATA CONTROL
PARALLEL AND SERIAL I/O CONTROL
MCUFLT
MCUREC
NLOAD
COM
HSCK
+5VDC
+12VDC
–12VDC
GND
J1
MCU
I/O
J11
C
O
N
T
R
O
L
P
A
N
+5V E
L
GND
MCU
HAMMER
DRIVER
MECH
DRIVER
2–17