Data Word Formats
9-42
ADSP-2126x SHARC Processor Hardware Reference
These formats are applied to serial data words loaded into the receive and
transmit buffers. Transmit data words are not zero-filled or sign-extended,
because only the significant bits are transmitted.
Linear transfers occur in the primary channel, if the channel is active and
companding is not selected for that channel. Companded transfers occur
if the channel is active and companding is selected for that channel. The
Multichannel Compand Select registers,
MTxCCSy
and
MRxCCSy
, specify the
transmit and receive channels that are companded.
Transmit or receive sign extension is selected by bit 0 of
DTYPE
in the
SPCTLx
register and is common to all transmit or receive channels. If bit 0
of
DTYPE
is set, sign extension occurs on selected channels that do not have
companding selected. If this bit is not set, the word contains zeros in the
MSB positions. Companding is not supported for B channel. For B chan-
nels, transmit or receive sign extension is selected by bit 0 of
DTYPE
in the
SPCTLx
register.
Companding
Companding (compressing/expanding) is the process of logarithmically
encoding and decoding data to minimize the number of bits that must be
sent. The serial ports support the two most widely used companding algo-
rithms, A-law and
-law, performed according to the CCITT G.711
specification. The type of companding can be selected independently for
Table 9-4. DTYPE and Data Formatting (Multichannel)
DTYPE
Data Formatting
x0
Right-justify, zero-fill unused MSBs
x1
Right-justify, sign-extend into unused MSBs
0x
Compand using
-law (primary A channels only)
1x
Compand using A-law (primary A channels only)
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 ...