Sharp XE-A212, Service Manual

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XE-A212V HARDWARE DESCRIPTION
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3. PRINTER CONTROL
3-1. STEPPING MOTOR CONTROL
The two phase Bi-Polar stepping motor is driven at a constant voltage
by SANYO LB1838M.
1step: 0.087mm, 1dot: 2step
< CPU’s PORT >
< Driving steps >
*
When the motor is at rest, the same phase as the final excitation
phase is RUSH energize to turn off all phases.
3
Turn ENA1 and
ENA2 into L.
No energizing should be allowed at lease 40 ms after stopping the
motor before restarting.
When starting the motor etc, required the chopping
3-2. HEAD CONTROL
HEAD: 288 dots in all, width: 0.167mm/dot (6dot/mm)
<Related PORT>
Conduction pulse width: Refer to the M-T53
II
specifications.
*
When turning on or off the printer power supply, make sure to turn
/STB1, 2 to “H”.
*
Do not turn on without paper.
*
THERMAL HEAD power supply control : Turns ON when P105= “H”;
turns OFF when “L”. (The power supply for HEAD and STEPPING
MOTOR is shared). When printing is finished (when the motor is
stopped) Athe power should be turned OFF.
*
Before printing or feeding paper, perform A/D conversion in 20 ms
after the printer head is turned ON and make sure the voltage is sta-
ble.
(The power supply of the printer head should be turned ON and OFF
by using the regulator IC.)
*
The head rank confirmation was abolished.
3-3. WINDING MOTOR CONTROL
<Related port>
3-4. PAPER EMPTY DETECTION
When LOW is detected twice continuously in sampling of signals for
every one dot line, it is judged as paper empty.
The threshold level of High/Low level is 2.5
m
0.2V. (Vcc = 5VDC
m
5%)
When paper empty is detected, printing is terminated. However, when
paper empty is detected during printing, 15-dot lines from detection of
paper empty can be printed.
3-5. PLATEN OVER
When signals are sampled in the frequency of 1ms or less and open
state is detected twice continuously, it is judged as platen over.
If the head is conducted under the platen over state, the thermal head
life may be shortened. When, therefore, platen over is detected, printing
is terminated.
Under the platen over state (switch open state), driving the paper feed
motor is inhibited.
No. CPU PORT Signal to be used
76 P14 IN1
75 P15 IN2
74 P16 ENA1
73 P17 ENA2
Driver IC input
(CPU output)
Motor driving signal
STEP IN1 IN2 ENA1 ENA2
A
(OUT1)
B
(OUT3)
/A
(OUT2)
/B
(OUT4)
1 L L H H H H L L
2 H L H H L H H L
3 H H H H L L H H
4 L H H H H L L H
No. I/O PORT Function
Signal
name
Initial
value
Port setup
in single
chip mode
18 OUT P84
PRINTING
/STB2
H
Out L
89 OUT P107
PRINTING
/STB1
H
Out L
30 OUT P70 TXD2
PRINTING
DAT
(Print DATA)
H
Out L
28 OUT P72 CLK2
PRINTING
PCLK
(Transfer Clock)
Out L
90 OUT P106
PRINTING
/LAT
(DATA Latch)
H
Out L
91 OUT P105
PRINTING
VPON (Head
motor POWER
SUPPLY)
L
Out L
/STB1: 1 ~ 144 dot: 144 dots in all
Total 288 dots
/STB2: 145 ~ 288 dot: 144 dots in all
OFF time of print strobe : Conduction strobe OFF time between dots
min. 160us
Logo print ratio restriction : Average print ratio 35% or below (Same as
the M-T51)
When the print ratio at the peak one-dot
line is 50%, the average print ratio of 10-
dot line including the above line should be
35% or less.
No. I/O PORT Function
Signal
name
Initial
value Port setup in
single chip mode
21 Out P81 Printer motor
(Winding motor)
L ON