
ADSP-2126x SHARC Processor Hardware Reference
9-19
Serial Ports
The I
2
S bus transmits audio data and control signals over separate lines.
The data line carries two multiplexed data channels—the left channel and
the right channel. In I
2
S mode, if both channels on a SPORT are set up to
transmit, then SPORT transmit channels (
TXSPxA
and
TXSPxB
) transmit
simultaneously, each transmitting left and right I
2
S channels. If both
channels on a SPORT are set up to receive, the SPORT receive channels
(
RXSPxA
and
RXSPxB
) receive simultaneously, each receiving left and right
I
2
S channels. Data is transmitted in MSB-first format.
SHARC SPORTs are designed such that in I
2
S master mode,
LRCLK is held at the last driven logic level and does not transition,
to provide an edge, after the final data word is driven out. There-
fore, while transmitting a fixed number of words to an I
2
S receiver
that expects an LRCLK edge to receive the incoming data word,
the SPORT should send a dummy word after transmitting the
fixed number of words. The transmission of this dummy word tog-
gles LRCLK, generating an edge. Transmission of the dummy
word is not required when the I
2
S receiver is a SHARC SPORT.
If the
MCEA
or
MCEB
bits are set (=1) in the
SPMCTLxy
register, the
SPEN_A
and
SPEN_B
bits in the
SPCTL
register must be cleared (=0).
Multichannel operation and companding are not supported in I
2
S
mode. See
“Multichannel Operation” on page 9-24
.
Each SPORT transmit or receive channel has a channel enable, a DMA
enable, and chaining enable bits in its
SPCTLx
Control register. The
SPORTx_FS
signal is used as the transmit and/or receive word select signal.
DMA-driven or interrupt-driven data transfers can also be selected using
bits in the
SPCTLx
register.
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...