ADSP-BF537 Blackfin Processor Hardware Reference
12-37
SPORT Controllers
Data Independent Transmit Frame Sync
Normally the internally generated transmit frame sync signal (
TFS
) is out-
put only when the
SPORTx_TX
buffer has data ready to transmit. The
data-independent transmit frame sync select bit (
DITFS)
allows the contin-
uous generation of the
TFS
signal, with or without new data. The
DITFS
bit
of the
SPORTx_TCR1
register configures this option.
When
DITFS
=
0
, the internally generated
TFS
is only output when a new
data word has been loaded into the
SPORTx_TX
buffer. The next
TFS
is gen-
erated once data is loaded into
SPORTx_TX
. This mode of operation allows
data to be transmitted only when it is available.
When
DITFS
=
1
, the internally generated
TFS
is output at its programmed
interval regardless of whether new data is available in the
SPORTx_TX
buffer. Whatever data is present in
SPORTx_TX
is transmitted again with
each assertion of
TFS
. The
TUVF
(transmit underflow status) bit in the
SPORTx_STAT
register is set when this occurs and old data is retransmitted.
The
TUVF
status bit is also set if the
SPORTx_TX
buffer does not have new
data when an externally generated
TFS
occurs. Note that in this mode of
operation, data is transmitted only at specified times.
Figure 12-12. Normal Versus Alternate Framing
B3
B2
B1
B0
...
xSCLK
DATA
EARLY
FRAME
SYNC
LATE
FRAME
SYNC
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 ...