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M16C/5L Group, M16C/56 Group
Sawtooth Waveform as a Carrier Wave
Carrier wave
Signal wave
TB2S bit
in the TABSR register
Timer B2
IR bit in the TB2IC register
(timer B2 interrupt request)
Timer A4
(1)
start trigger signal
Timer A4
(1)
one-shot pulse
(1)
U-phase output signal
(1)
U-phase output signal
(1)
Dead time timer output
U-pin output
INV14 = 0
(active low)
U-pin output
U-pin output
INV14 = 1
(active high)
U-pin output
The above diagram assumes the following:
In the INVC1 register
- The INV10 bit is 0 (Timer B2 underflow is a start trigger for timers A1, A2 and A4.).
- The INV15 bit is 0 (dead time timer enabled).
- The INV16 bit is 0 (the dead time timer is triggered on the falling edge of timers A4, A1 and A2 one-shot pulse).
The ICTB2 register is 1h (timer B2 interrupt request is generated at every timer B2 underflow).
Bits PFC1 to PFC0 in the PFCR register are 11b (U-, U-phase outputs).
In registers IDB0 and IDB1
- Initial values: DU0 = 0; DUB0 = 1; DU1 = 1; DUB1 = 1
- At the fourth timer B2 interrupt, the values are changed to DU0 = 1; DUB0 = 1; DU1 = 1; DUB1 = 1.
- At the sixth timer B2 interrupt, the values are changed to: DU0 = 1; DUB0 = 0; DU1 = 1; DUB1 = 1.
Note:
1. Internal signal. See
Figure 17.9
Example of Sawtooth Wave Modulation Mode Operation
R01UH0127EJ0110 Rev.1.10
Sep 01, 2011
Rewrite registers IDB0 and IDB1
Figure 17.1.
17. Three-Phase Motor Control Timer Function
The rewritten values are reflected at these points.
Dead time
Page 340 of 803
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