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ADSP-BF50x Blackfin Processor Hardware Reference
14-27
PWM Controller
Brushless DC Motor (Electronically Commutated Motor)
Control
In the control of an electronically commutated motor (ECM), only two
inverter legs are switched at any time. Often, the high-side device in one
leg must be switched on at the same time as the low-side driver in a second
leg. Therefore, by programming identical duty cycles values for two PWM
channels (for example,
PWM_CHA
=
PWM_CHB
) and setting the
BHBL_XOVR
bit
of the
PWM_SEG
register to crossover the
BH
/
BL
pair if PWM signals, it is
possible to turn on the high-side switch of phase A and the low-side
switch of phase B at the same time.
In ECM control, usually the third inverter leg (phase C in this example) is
disabled for a number of PWM cycles. This is implemented by disabling
the
CH
and
CL
outputs by setting the
CH_EN
and
CL_EN
bits of the
PWM_SEG
register.
This is illustrated in
Figure 14-7
where it can be seen that both the
AH
and
BL
signals are identical (since
PWM_CHA
=
PWM_CHB
and the crossover bit for
phase B is set). In addition, the other four signals (
AL
,
BH
,
CH
, and
CL
) are
disabled by setting the appropriate enable/disable bits of the
PWM_SEG
register.
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...