Sharp ER-04RP Service Manual page 10

ER-04RP
7)
Interface circuit with the operation panel
As shown in Fig.5-9, the operation panel circuit includes switches; an
online switch and a line feed switch. The switches are connected to
the respective input ports of the CPU, while the LEDs are mnnected
to the output ports through the drivers.
-- —._
--—-—-—-—-—-—-
—. —-—-—-—
1
I I
Vcc
I
I b
I
L
A
1
1 i
I
I
I
t
SwI —
ON-LINE
I
r"
.
T
P42
t-
+ SW ~ FEED
A
1
P43
~
A
b '
T T
L- —-—-—-—-—-—-- ;
L.–._._.–-–.–.–
Fig.5-9 Operation panel circuit
8)
Cutter control
me cutter control is as shown in Fig. 2-9. "M" on the cutter side
means "Motor" and "S" means "Switch.'l The control circuit inputs X
and Y are controlled as shown in the table below to rotate the motor
forward or backward.
Forward
Reverse stop stop
x
H L L H
Y
L H
L H
Fig. 2-8 shows the timing chart. On falling of S in forward rotation of
the motor, the cutter returns t~ its home position and the motor stops.
In full cut, the motor rotates forward only. The blade goes and returns
the home position once. In partial cut, the motor rotates forward, and
rotates reversely midway during cutting, and rotates forward again to
stop at the home position.
2oms
Fig 2-8. Time chart
CPU
–-~—-- ""+
_–l–
" - +
II I ,..
1
OwY
5-3. SRN interface circuit
1)
Circuit description
The SRN interface is allocated at the 1/0 space address, with the
printer controller as the host CPU, and transfers data for interfacing
using seven interface registers.
Data is transferred to and from the external devices at IM bps using
a coaxial cable. (RG-58U)
* f
~ y-
CPU
Z-80
DMA
BUS
IF
ROM
ADLC
RAM
link
MOD.
controller
A
Printer controller
T
qlq
Driver
Receiver
I
1
1Mbps
DATA
Fig.5-10 SRN intedace block diagram
2) Adjustment
The duty adjustment of the interface is carried out in the following
manner.
1. Set the oscillator.
IMHz
P-P 5V Ou@ut impedance
5V
a
Check on oscilloscope
Ov
b
'0.w sTo.5p Sq
+
Fig.
2, Connect a dummy network to the printer.
Connect the oscillator and the oscilloscope as shown below.
5-11
Fig. 2-9. Cutter control circuit
-8-
Fig. 5-12