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ADSP-BF537 Blackfin Processor Hardware Reference
12-33
SPORT Controllers
Active Low Versus Active High Frame Syncs
Frame sync signals may be either active high or active low (in other words,
inverted). The
LTFS
and
LRFS
bits of the
SPORTx_TCR1
and
SPORTx_RCR1
registers determine frame sync logic levels:
• When
LTFS
=
0
or
LRFS
=
0
, the corresponding frame sync signal
is active high.
• When
LTFS
=
1
or
LRFS
=
1
, the corresponding frame sync signal
is active low.
Active high frame syncs are the default. The
LTFS
and
LRFS
bits are initial-
ized to 0 after a processor reset.
Sampling Edge for Data and Frame Syncs
Data and frame syncs can be sampled on either the rising or falling edges
of the SPORT clock signals. The
TCKFE
and
RCKFE
bits of the
SPORTx_TCR1
and
SPORTx_RCR1
registers select the driving and sampling edges of the
serial data and frame syncs.
For the SPORT transmitter, setting
TCKFE = 1
in the
SPORTx_TCR1
register
selects the falling edge of
TSCLKx
to drive data and internally generated
frame syncs and selects the rising edge of
TSCLKx
to sample externally gen-
erated frame syncs. Setting
TCKFE = 0
selects the rising edge of
TSCLKx
to
drive data and internally generated frame syncs and selects the falling edge
of
TSCLKx
to sample externally generated frame syncs.
For the SPORT receiver, setting
RCKFE = 1
in the
SPORTx_RCR1
register
selects the falling edge of
RSCLKx
to drive internally generated frame syncs
and selects the rising edge of
RSCLKx
to sample data and externally gener-
ated frame syncs. Setting
RCKFE = 0
selects the rising edge of
RSCLKx
to
drive internally generated frame syncs and selects the falling edge of
RSCLKx
to sample data and externally generated frame syncs.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...