Epson DFX-5000+, Service Manual

Page: 74 / 223

Operating Principles
The reset circuit outputs the reset signal when the printer is turned on or off, the
voltage level drops, or a reset signal is input from an external device. It resets the
control circuit for a certain period directly or via the
gate array
P - R O M
( l C 4 )
S - R A M
( l C 3 )
A d d r e s s B
D a t a B u s
I n t e r f a c e
C P U
( l C 7 )
R F M o t o r
P F M o t o r
E E P R O M
R E S E T I C
S e n s o r C i r c u i t s
( t o p ) ( f r o n t ) ( r e a r )
J a m H o m e
T r a c t o r S e l e c t
O p e n
T e m p e r a t u r e
M o t o r
H e a d T e m p e r a t u r e
M o t o r W a t c h D o g
E r r o r
( f r o m B o a r d A s s e m b l y )
F a n
,
P G M o t o r
Figure 2-18. Control Circuit Block Diagram
S e n s o r
e n c o d e r s e n s o r
e n c o d e r s e n s o r
s e n s o r
Figure 2-19 shows the data flow for data input via the parallel interface. Although
various circuits perform data processing, the control core is the CPU and all
operations are executed via the CPU. In this circuit, the gate array IC (IC7)
provides the interface between the external host computer and the CPU, and all
data processing is performed by read/write operations to
(Memory Mapped
Input/Output).
2-22
EPSON Service Manual