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Figure 15.3 shows the PWM waveforms generated by the PWM wave-generating circuit.
When the compare register value is 00
PWM waveform
When the compare register value is 80
PWM waveform
When the compare register value is FF
PWM waveform
• Selection of motor drive signal
Four motor drive signals that are output to each pin related to the stepping motor controller can be selected
by the settings of PWM select registers.
Table 15-1 shows the selection of motor drive signals and the settings of the PWM select registers 1 and
2.
When 1 is written to the BS bit of the PWM select register 2, the setting becomes valid at the end of the
current PWM cycle. The BS bit is cleared automatically at the beginning of the next PWM cycle. If writing
1 to the BS bit and clearing the BS bit at the beginning of the PWM cycle occur at the same time, writing is
preferred to clearing, and clearing the BS bit will be cancelled.
Table 15-1 Selection of Motor Drive Signals and Settings of PWM Select Registers 1 and 2
P2, P1, P0 Bit
STEPPING MOTOR CONTROLLER
000
H
Counter value 00
H
H
L
000
H
Counter value 00
H
H
L
000
H
Counter value 00
H
H
L
Fig. 15.3 Example of PWM 1, 2 Waveform Output
PWM1P Output
PWM2P Output
000
L
B
001
H
B
01X
PWM wave
B
1XX
High impedance
B
/000
(duty ratio: 0%):
H
H
3FF
/200
(duty ratio: 50%):
H
H
200
3FF
H
80
H
/3FF
(duty ratio: 99.6%/99.9%):
H
H
3FF
1 count
M2, M1 and M0 Bit
000
B
001
B
01X
B
1XX
B
15-9
000
H
H
FF
00
H
H
000
H
H
FF
00
H
H
000
H
H
FF
00
H
H
PWM1M Output
PWM2M Output
L
H
PWM wave
High impedance
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