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The three-phase motor control timer function is enabled by setting the INV02 bit in the VC0 register to "1".
When this function is on, timer B2 is used to control the carrier wave, and timers A4, A1 and A2 are used to
control three-phase PWM outputs (U, U, V, V, W and W). The dead time is controlled by a dedicated dead-
time timer. Figure 12.3.9 shows the example of triangular modulation waveform, and Figure 12.3.10 shows
the example of sawtooth modulation waveform.
Triangular waveform as a Carrier Wave
Triangular wave
TB2S bit in the
TABSR register
Timer B2
Start trigger signal
(1)
for timer A4
Timer A4
(1)
one-shot pulse
U phase
output signal
U phase
output signal
U phase
INV14 = 0
("L" active)
U phase
U phase
INV14 = 1
("H" active)
U phase
INV13
(INV11=1(three-phase
mode 1))
NOTE:
1. Internal signals. See Figure 12.3.1.
The above applies under the following conditions:
INVC0 = 00XX11XX
Examples of PWM output change are:
(1)When INV11 = 1 (three-phase mode 1)
· INV01 = 0 and ICTB2 = 2
every two times the timer B2 underflows),
or INV01 = 1, INV00 = 1, and ICTB2=1
generated at the falling edge of the timer A1 reload control signal.)
· Default value of the timer: TA41 = m, TA4 = m.
Registers TA4 and TA41 are changed whenever the timer B2
interrupt is generated.
First time, TA41 = n, TA4 = n. Second time, TA41 = p, TA4 = p.
· Default values of registers IDB0 and IDB1:
DU0 = 1, DUB0 = 0, DU1 = 0, DUB1 = 1.
They are changed to DU0 = 1, DUB0 = 0, DU1= 1 and DUB1 = 0
when the third timer B2 interrupt is generated.
The value written to registers TA4 and TA41 becomes effective at the rising edge of the timer A1 reload control signal.
Figure 12.3.9. Triangular Wave Modulation Operation
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2
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0
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, 5
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0
0
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R
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B
0
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0
2
0 -
2
0
0
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, A
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, B
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Signal wave
m
m
(1)
(1)
(X varies depending on each system) and INVC1 = 010XXXX0
2
(the timer B2 interrupt is generated
16
(the timer B2 interrupt is
16
page 126
f o
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___
___
n
n
Dead time
Dead time
.
2
(2)When INV11 = 0 (three-phase mode 0)
· INV01 = 0, ICTB2 = 1
whenever timer B2 underflows)
· Default value of the timer: TA4 = m. The TA4 register is changed
whenever the timer B2 interrupt is generated.
First time: TA4 = m. Second tim:, TA4 = n.
Third time: TA4 = n. Fourth time: TA4 = p.
Fifth time: TA4 = p.
· Default values of registers IDB0 and IDB1:
DU0 = 1, DUB0 = 0, DU1 = 0, DUB1 = 1.
They are changed to DU0 = 1, DUB0 = 0, DU1 = 1, and DUB1 = 0
when the sixth timer B2 interrupt is generated.
p
p
Rewrite registers IDB0 and IDB1
Transfer the values
to the three-phase
output shift register
(the timer B2 interrupt is generated
16
12. Timer
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