Sharp ER-1910 Service Manual page 7

ER-2395
_ 4-6. Key and switch read.
P20-P21, P30-P38.
KDC
#MPD7507C
O86 YP
Key
sye.-Matrix.
Receipt. 1 ;
on/OFF SW
| .P10-P13
P60—P62 _
47KOX7
Fig. 4-15
Signal description
P20, P21, P30~P33, P70~P73: Key. anid Switch scan signal
P10~P13; P60~P62: Key and' switch returns signal
RESET: KDC reset signal
Iscan cycle=10.Ims
P30
Pll
v rc on a)
P 62
key
- Fig. A- 16
Fig.4-16 shows that the [RA] key is being depressed: for Pit is at
a high level in the time of P33.
When the KDC recognizes the key depressed, data is sent on the
STH line in response to the request from the CPU.
4-7. Display control
. as | | DRIVER
CPU KDC
SC 1038C
ae
Tet
d Pies
Fig. es Te
Signal description
*1: P20, P30~P33, P70~P73(1G~9G): Display digit signal :
*2: P43~P40, P53~P50, P63(a~g, WV, DP): Display segment signal
P43 (DP): Decimal point
1° §$C1083C -
VPO
The display data is sent from the CPU to the KDC with the HTS
signal and displayed via the display tube driver..Once the KDC
received the display data from the CPU, the display i is controlled by
the KDC until a next data is received. |
Display tube driver |
Since a fluorescent tube is used for the display, the' 'digplay digit
and segment signals are operated by about +34V. The LB1292 is
used to convert the signal from the TTL level to the +34V level.
an i
P
ey) GND
+ 34-V
: +5V-
High | High : +34V
it
a Np
Low
: GND
LB1292: Driverx6 circuits
For more details of the aiiae tube, refer to Cash Register Basic
..Manual, Chapter. 9-3. . sie
4-8. Printer control
- LB1234& 4
MG 1—MG10
Printer
CR802A,
CR812A
or
CR911D
Signal name
RM1~RM10 _ : Receipt magnet select signal
JMi~JM10 : Recording magnet select signal
JF-JF_ : Journal feed signal
RF-RF : Receipt feed signal
STMP-STAMP_: Stamp signal
a : Printer interface signal
IDF : Motor drive signal
JCOM : Journal common signal
RCOM : Receipt common signal _ .
For detail of printer, refer to CR802A, CR812A, CR911D, CR-802,
CR-812, and CR-911A Printer Manual.
Motor drive circuit
eee nee ee eee ee eee ete me cme
TON
25B926
Q5
Printer
motor
Fig.4-20
_ With a high state of IDF, the base voltage of Q7 starts to decrease
via 1C4 and Q7 goes active which causes ION to flow through the
- motor to run it.
'When IDF goes low, Q7 comes inactive and - turns on. With this,
igs is $ applied, to a the motor quickly. .