Dip Switch Read Circuit - Epson TM U200D - B/W Dot-matrix Printer Technical Manual

DIP switch read circuit

There are 8 switches in DIP switch bank 1 and 2 switches in DIP switch bank 2 that are status
readable switches. Each signal is input to the CPU. The signal is read as LOW when the switch is
On, and HIGH when the switch is Off.
CPU (U5) pin 52 to 55, pin 56 to 59, and pins 1 and 81 are also used for the Motor, carriage drive
circuit, Motor, paper feed drive circuit, and operation panel control circuit. The pins are used to
read DIP switches temporarily immediately after the printer initialization (or the power is
turned on).
U5
(*1): Resistance between E and B is used for pull-up resistors in the transistor.
2-24 Mechanism Configuration and Operating Principles
{5V
( (*1) 1)
Q14 Q15 Q16 Q17 Q18 Q19 Q20 Q21
52
P20
53
P21
54
P22
55
P23
56
P90
57
P91
58
P92
59
P93
1 2 3 4
D24 D23 D22 D21 D20 D19 D18 D17
1
P57
80
P56
{5 V
R33
Q38
3
P100
{5 V
R32
Q28
4
P101
Figure 2-23 DIP switch read circuit
DSW1
5 6 7 8
{5 V
R29
Q39
Q36 Q35
DSW2
1 2
D14 D25
Rev.B