ADSP-214xx SHARC Processor Hardware Reference
10-15
Serial Ports
The
SPORTx_DA
or
SPORTx_DB
signal is always driven if the serial
port is enabled as transmitter (
SPEN_A
or
SPEN_B
= 1 in the
SPCTLx
control register), unless it is in multichannel mode and an inactive
time slot occurs.
When the SPORT is configured as a transmitter (
SPTRAN
= 1), the
TXSPxA
and
TXSPxB
buffers, and the channel transmit shift registers respond to
SPORTx_CLK
and
SPORTx_FS
to transmit data. The receive
RXSPxA
and
RXSPxB
buffers, and the receive shift registers are inactive and do not
respond to
SPORTx_CLK
and
SPORTx_FS
signals. Since these registers are
inactive, reading from an empty buffer causes the core to hang
indefinitely.
When the SPORT is configured as a transmitter (
SPTRAN
= 1), the trans-
mit buffers are activated. The transmit buffers act like a two-location
FIFO because they have one data registers plus an output shift register.
Receive Path
If the serial data signal is configured as a serial receiver (
SPTRAN
= 0), the
receive portion of the SPORT shifts in data from the
SPORTx_DA
or
SPORTx_DB
signal, synchronous to the
SPORTx_CLK
receive clock. If framing
signals are used, the
SPORTx_FS
signal indicates the beginning of the serial
word being received. When an entire word is shifted in on the primary A
channel, the data is (optionally) expanded (SPORT1, 3, 5 and 7 only),
then automatically transferred to the
RXSPxA
buffer. When an entire word
is shifted in on the secondary channel, it is automatically transferred to the
RXSPxB
buffer.
When the SPORT is configured as a receiver (
SPTRAN
= 0), the
RXSPxA
and
RXSPxB
buffers, and the channel receive shift registers respond to
SPORTx_CLK
and
SPORTx_FS
for reception of data. The transmit
TXSPxA
and
TXSPxB
buffer registers and transmit A and B shift registers are inactive and
do not respond to the
SPORTx_CLK
and
SPORTx_FS
. Since the
TXSPxA
and
TXSPxB
buffers are inactive, writing to a transmit data buffer causes the
core to hang indefinitely.
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Содержание SHARC ADSP-214 Series
Страница 60: ...Contents lx ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 290: ...Programming Model 4 26 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 656: ...Programming Model 15 40 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...