Analog Devices ADSP-BF59x Blackfin, Hardware Reference Manual, Page: 533 / 772

ADSP-BF59x Blackfin Processor Hardware Reference 14-27
SPORT Controller
Word Length
Each SPORT channel (transmit and receive) independently handles word
lengths of 3 to 32 bits. The data is right-justified in the SPORT data reg-
isters if it is fewer than 32 bits long, residing in the LSB positions. The
value of the serial word length (
SLEN
) field in the
SPORT_TCR2
and
SPORT_RCR2
registers of each SPORT determines the word length accord-
ing to this formula:
Serial Word Length =
SLEN
+ 1

The
SLEN
value should not be set to 0 or 1; values from 2 to 31 are
allowed. Continuous operation (when the last bit of the current
word is immediately followed by the first bit of the next word) is
restricted to word sizes of 4 or longer (so
SLEN
≥
3).
Bit Order
Bit order determines whether the serial word is transmitted MSB first or
LSB first. Bit order is selected by the
RLSBIT
and
TLSBIT
bits in the
SPORT_RCR1
and
SPORT_TCR1
registers. When
RLSBIT
(or
TLSBIT
) =
0
, serial
words are received (or transmitted) MSB first. When
RLSBIT
(or
TLSBIT
) = 1, serial words are received (or transmitted) LSB first.
Data Type
The TDTYPE field of the SPORT_TCR1 register and the RDTYPE field
of the SPORT_RCR1 register specify one of four data formats for both
single and multichannel operation. See
Table 14-4 on page 14-28 .
These formats are applied to serial data words loaded into the
SPORT_RX
and
SPORT_TX
buffers.
SPORT_TX
data words are not actually zero filled or
sign extended, because only the significant bits are transmitted.