Overview
14-6
ADSP-BF50x Blackfin Processor Hardware Reference
The PWM generator is capable of operating in two distinct modes:
•
Single-Update Mode
. In single-update mode, duty cycle values are
programmable only once per PWM period; resultant PWM pat-
terns are symmetrical about the mid-point of the PWM period.
•
Double-Update Mode
. In double-update mode, a second updating
of the PWM registers is implemented at the midpoint of the PWM
period. In double-update mode, it is possible to produce asymmet-
rical PWM patterns that produce lower harmonic distortion in
three-phase PWM inverters. This technique also permits
closed-loop controllers to change the average voltage applied to the
machine windings at a faster rate, thus permitting faster
closed-loop bandwidths to be achieved.
The operating mode of the PWM block (single- or double-update mode)
is selected by the
PWM_DBL
bit in the
PWM_CTRL
register. Setting
PWM_DBL
to 1 selects double-update mode, and 0 selects single-update mode.
The PWM generator can provide an internal synchronization pulse on the
PWM_SYNC
pin that is synchronized to the PWM switching frequency. In
single-update mode, a
PWM_SYNC
pulse is produced at the start of each
PWM period. In double-update mode, an additional
PWM_SYNC
pulse is
also produced at the midpoint of each PWM period. The width of the
PWM_SYNC
pulse is programmable through the
PWM_SYNCWT
register.
The PWM generator can also accept an external synchronization pulse on
the
PWM_SYNC
pin. External synchronization is selected by setting the
PWM_EXTSYNC
bit in the
PWM_CTRL
register. The
PWM_SYNC
input timing can
be synchronized to the internal system clock, which is selected by setting
the
PWM_SYNCSEL
bit of the
PWM_CTRL
register. If the external synchroniza-
tion pulse from the chip pin is asynchronous to the internal system clock
(typical case), the external
PWM_SYNC
is considered asynchronous and
should be synchronized. If the
PWM_SYNC
is actually received from another
PWM on the same chip controlled by the same system clock, the
PWM_SYNC
can usually be considered synchronous. Synchronization logic will add
Содержание EZ-KIT Lite ADSP-BF506F
Страница 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 132: ...Unique Information for the ADSP BF50x Processor 4 22 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 342: ...Unique Information for the ADSP BF50x Processor 7 106 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 484: ...Unique Information for the ADSP BF50x Processor 10 60 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 493: ...ADSP BF50x Blackfin Processor Hardware Reference 11 9 Core Timer Unique Information for the ADSP BF50x Processor None ...
Страница 494: ...Unique Information for the ADSP BF50x Processor 11 10 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 506: ...Unique Information for the ADSP BF50x Processor 12 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 544: ...Unique Information for the ADSP BF50x Processor 13 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 712: ...Unique Information for the ADSP BF50x Processor 16 62 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 972: ...Unique Information for the ADSP BF50x Processor 20 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...