ADSP-BF537 Blackfin Processor Hardware Reference
12-31
SPORT Controllers
Framed Versus Unframed
The use of multiple frame sync signals is optional in SPORT communica-
tions. The
TFSR
(transmit frame sync required select) and
RFSR
(receive
frame sync required select) control bits determine whether frame sync sig-
nals are required. These bits are located in the
SPORTx_TCR1
and
SPORTx_RCR1
registers.
When
TFSR
=
1
or
RFSR
=
1
, a frame sync signal is required for every data
word. To allow continuous transmitting by the SPORT, each new data
word must be loaded into the
SPORTx_TX
hold register before the previous
word is shifted out and transmitted.
When
TFSR
=
0
or
RFSR
=
0
, the corresponding frame sync signal is not
required. A single frame sync is needed to initiate communications but is
ignored after the first bit is transferred. Data words are then transferred
continuously, unframed.
a
With frame syncs not required, interrupt or DMA requests may
not be serviced frequently enough to guarantee continuous
unframed data flow. Monitor status bits or check for a SPORT
Error interrupt to detect underflow or overflow of data.
illustrates framed serial transfers, which have these
characteristics:
•
TFSR
and
RFSR
bits in the
SPORTx_TCR1
and
SPORTx_RCR1
registers
determine framed or unframed mode.
• Framed mode requires a framing signal for every word. Unframed
mode ignores a framing signal after the first word.
• Unframed mode is appropriate for continuous reception.
• Active low or active high frame syncs are selected with the
LTFS
and
LRFS
bits of the
SPORTx_TCR1
and
SPORTx_RCR1
registers.
See
“Timing Examples” on page 12-39
for more timing examples.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...