Video Interface; Font Cartridge Interface - HP LaserJet II Serie Manual De Instrucciones

HP 33440/HP 33449 COMBINED SERVICE MANUAL
1/0 Controller
The 1/0 controller controls the timing of data input from on optional 1/0 PCA to the
microprocessor via the parallel interface connector. It dso controls the timing of communication
with the DC ControUer.
Video Interface
The video interface has tio 4-~~e
scan buffer memories (SWS) through which printing
information converted to dot dati is output continuously to the DC Controller.
Font Cartridge Interface
"Font mrtridges" are ROM cartridges which hold additiond dot pattern data for different fonts.
The font cartridge interface buffers the main bus from the font cartridge connectors.
Descriptions of Blocks in the HP 33449 Formatter PCA Diagram
General
The Block Diagram of the HP 33449 Formatier PCA is shown in Figure 5-18. An explanation of
the blocks within the diagram follows:
mm
Optional
~
Dptiona[
68000 Standard
Cartridge
–L HE,
Cartridge
10MHz
EPRBM
n
CPU
HR RDM
J6
Serla(1/0
(Right) (Left)
J2
I
System Bus
1
1 II "
DptionaLV 1/0
Operator
EngineInterface
Expended
Pane(
NVRAM
J1
1/0 J9
J8
(to DC Contro((er)
Figure 5-18. HP 33449 Formatter Block Diagram
5-19