Epson FX-980 - Impact Printer, Руководство по обслуживанию, Страница: 31 / 72

FX-980 Revision A
Operating Principles Control Circuit 31
The following figure shows the data flow from the host computer to the
printhead. Data sent from the host computer is converted to image data
and transmitted to the printhead through the gate array.
Figure 2-2. Data Flow
The table below lists the each function of the main components of the
C276 Main Board.
Table 2-1. Functions of the Main Board
C P U
T M P 9 6 C 1 4 1
G a t e A r r a y
E 0 5 B 5 0
P r i n t h e a d d r i v e
c i r c u i t
P r i n t d a t a
c o n v e r s i o n 1
P r i n t d a t a
c o n v e r s i o n 2
D a t a l a t c h
a n d
d a t a o u t p u t
I m a g e d a t a
t r a n s f e r
R A M
I n p u t
B u f f e r
I m a g e
B u f f e r
L i n e E d i t
B u f f e r
I C 7
T r a n c e i v e r
H o s t
C o m p u t e r
P a r a l l e l I / F
O p t i o n I / F
S e r i a l I / F
IC Location Function
CPU IC 2
Receives data from the host computer and sends it
to the input buffer in RAM (under interrupt
processing control). Extends the input data held in
the buffer to create image data. Loads this image
data to the image buffer in RAM. Transfers the
image data to the printhead driver circuit.
Gate Array IC 1
Controls the functions below:
• Controls output data from the internal block
• Memory management
• Address latch of the address/data bus from the
CPU
• Clock control unit
• Bit manipulation
• Interface control
• Expanded parallel port
• Printhead control
• Motor control
EEPROM IC 8
An electrically writable and erasable ROM used to
hold such information as the TOF position and
bidirectional adjustment value.
ROM IC 5
The ROM contains the program that runs the CPU
and holds the character design (also called the
character generator).
RAM IC 3
The RAM contains the CPU working area and the
buffers.
SLA7024M IC 9 Driver circuit for the CR motor.
A2917SEB IC 12 Driver circuit for the PF motor.