Star Micronics TUP400 Series, Technical Manual

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2-3. Feed-Motor Drive Circuit
This printer employs a paper feed motor and a stepping motor. The motor rotates through a certain angle each time it
receives a pulse from the drive circuit. This printer employs a 4-phase stepping motor and controls the paper feed motor
with a phase 1-2 excitation method. The following diagram illustrates the phase 1-2 excitation method. Diagram 2-8
shows the feed-motor drive circuit.
Fig. 2-8 Motor Control by Phase 1-2 Excitation
Fig. 2-9 Feed-Motor Drive Circuit
Voltage to the motor is controlled to produced the required action, as follows.
Mode Voltage Action
Operating VM (+24V) Drives the motor
VL (+5V)
Idle VL (+5V) Holds the motor
Voltage is controlled by PA4 pin of the CPU, which goes HIGH or LOW to switch transistors DQ2 and Q2 ON and OFF.
When Q2 is ON, the paper feed motor receives VM (+24V). When Q2 is OFF, VL (+5V) is supplied to the motor via
diode D1.
1 2 3 4 5 6 7 8
1
2
3
4
ON
ON
ON
ON
ON
Step
Reverse Feed
Forward Feed
PA4
PA0
PA2
PA3
PA1
1
2
3
4
CN4
1
2
4
5
6
3
M
+5V +24V
Q2
D1
TA1
B
DQ2
M-GND
E
IC5
CPU
Paper Feed Motor