
Serial Inputs
11-4
ADSP-2126x SHARC Processor Hardware Reference
protocol is designed to receive audio channels in I
2
S, Left-justified Sample
Pair, or Right-justified mode. One frame sync cycle indicates one 64-bit
left-right pair, but data is sent to the FIFO as 32-bit words (that is,
one-half a frame at a time).
Contained within the 32-bit word is an audio signal that is normally 24
bits wide. An additional four bits are available for status and formatting
data (compliant with the IEC 90958, S/PDIF, and AES3 standards). An
additional bit identifies the left-right one-half of the frame. If the data is
not in IEC standard format, the serial data can be any data word up to 28
bits wide. Regardless of mode, bit 3 always specifies if the data is received
in the first half (left channel), or the second half (right channel) of the
same frame, as shown in
. The remaining three bits are used to
encode one of the eight channels being passed through the FIFO to the
core. The FIFO output may feed eight DMA channels, where the appro-
priate DMA channel (corresponding to the channel number) is selected
automatically.
Note that each input channel has its own clock and frame sync
input, so unused IDP channels do not produce data and therefore
have no impact on FIFO throughput. The clock and frame sync of
any unused input should be assigned to
LOW
to avoid unintentional
acquisition.
The framing format is selected by using
IDP_SMODEx
bits (three bits per
channel) in the
IDP_CTL
register. The bits
[31:8]
of the
IDP_CTL
register
control the input format modes for each of the eight channels. The eight
groups of three bits indicate the mode of the serial input for each of the
eight IDP channels, as shown in
.
Figure 11-3. Word Format
31
8 7
4
3
2
0
AUDIO DATA (24 BITS)
AUDIO STREAM
STATUS
L/R
IDP
CHNL
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 ...