Companding - Analog Devices ADSP-BF506F Hardware Reference Manual

Table 19-4. TDTYPE, RDTYPE, and Data Formatting
TDTYPE or
RDTYPE
00
01
10
11
These formats are applied to serial data words loaded into the
and buffers.
SPORT_TX
sign extended, because only the significant bits are transmitted.

Companding

Companding (a contraction of COMpressing and exPANDing) is the pro-
cess of logarithmically encoding and decoding data to minimize the
number of bits that must be sent. The SPORT supports the two most
widely used companding algorithms,
compands data according to the CCITT G.711 specification. The type of
companding can be selected independently for each SPORT.
When companding is enabled, valid data in the
right-justified, expanded value of the eight LSBs received and sign
extended to 16 bits. A write to
compressed to eight LSBs (sign extended to the width of the transmit
word) and written to the internal transmit register. Although the com-
panding standards support only 13-bit (A-law) or 14-bit (
maximum word lengths, up to 16-bit word lengths can be used. If the
magnitude of the word value is greater than the maximum allowed, the
value is automatically compressed to the maximum positive or negative
value.
Lengths greater than 16 bits are not supported for companding operation.
ADSP-BF50x Blackfin Processor Hardware Reference
SPORT_TCR1 Data Formatting
Normal operation
Reserved
Compand using -law
Compand using A-law
data words are not actually zero filled or
SPORT_TX
SPORT_TX
SPORT Controller
SPORT_RCR1 Data Formatting
Zero fill
Sign extend
Compand using -law
Compand using A-law

-law and A-law. The processor
SPORT_RX
causes the 16-bit value to be
SPORT_RX
register is the

-law)
19-29