Read Sharp XE-A110 Service Manual online
9. Keyboard circuit
KST2
∼
KST5 of the key strobe signal are used as the Mode switch
strobe signals.
10. Display circuit
One strobe signal drives two-digit LED.
KR2~KR5
CPU
KR1
KST1~KST18
KST1~
KST8
KST2~KST5
Key
Matrix
Matrix
Mode
Switch
Switch
ST1
ST2
ST3
ST4
ST5
KSTn
KSTm
1ms
30~100µs
n=1~4, m=5~8
Segment signals
Operator display
Customer display
(ER-A 130)
Co mmon sig na ls
CPU
CPU
ST1~5
SA
1
SB
1
SC
1
SD
1
SE
1
SF
1
SG
1
SD
P1
SA
2
SB
2
SC
2
SD
2
SE2
SF
2
SG
2
SD
P2
6V
Q8
6.8K
1K
ST
1
1
LED
LED
2.2K
12K
C3198
SA1~SG1
SDP1
12K
C3198
2.2K
SA2~SG2
SDP2
22
0
22
0
22
0
22
0
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