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1) Keyboard
Scan signal :
10 /S0-9 signals
Return signal :
6 P92-97 signals
The keys are read by the key matrix following the above signals.
2) Mode switch
Scan signal :
8 /S0-7 signals
Return signal :
1 P90 signal
The positions are read by the above signals.
Scan signal /S0
/S1
/S2
/S3
/S4
/S5
/S6
/S7
Mode switch
position
position
SRV
PGM (OFF) TIME REG MGR X1/Z1 X2/Z2
3) Paper feed key
Scan signal :
1 /S1 signal
Return signal :
1 P91 signal
The paper feed key is read by the above signals.
4) Head up sensor
Scan signal :
1 /S3 signal
Return signal :
1 P91 signal
The Head up sensor state is read by the above signals.
Head up sensor
Head up detected
Head up not detected
P91
Low
High
5) Receipt near end sensor
Scan signal :
1 /S4 signal
Return signal :
1 P91 signal
The receipt near end sensor state is read by the above signals.
Receipt near end sensor
Near end detected
Near end not detected
P91
Low
High
6) RS232/CI signal detection
Scan signal :
1 /S9 signal
Return signal :
1 P91 signal
The RS232/CI signal is detected by the above signals.
RS232 /CI signal
/CI signal detected
/CI signal not detected (+5V output)
P91
Low
High
7) Display
Scan signal :
10 /S0-9 signals
The above 10 scan signals are used as the following digit signals.
Digit signal :
Scan signal
/S0
/S1
/S2
/S3
/S4
/S5
/S6
/S7
/S8
/S9
Digit signal:
Front
G1’
G2’
G3’
G4’
G5’
G6’
G7’
G8’
G9’
G10’
Digit signal:
Pop-up
G1’
G2’
G3’
G4’
G5’
G6’
G7’
Segment signal : Segment signals: a, b, c, d, e, f, g, and DP are output
by the IC:74HC374, using the data bus signal:D0-7
from the CPU as an input signal and the chip select
signal:/CS3 as a latch signal.
12. RS232 circuit
The signals from the CPU are converted by the MAX211 into the RS232 level to input and output them.
The CI signal allows the output of VCC(+5V) by switching.
The CI signal allows the output of VCC(+5V) by switching.
CPU
MAX211
1
D-SUB 9pin connector
2
3
4
5
6
7
8
9
CD
RD
SD
ER
GND
DR
RS
CS
CI OR VCC(+5V)
R1IN
R2IN
T3OUT
T2OUT
R4IN
R5IN
T1OUT
R3IN
R1OUT
R2OUT
T3IN
R4OUT
T2IN
T1IN
R5OUT
R3OUT
P75
P66
P77
P67
P74
P64
P91
P76
ICP 0.5A
VCC(+5V)
/CD
RD
/SD
/ER
/DR
/RS
/CI
/S5
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