ADSP-2126x SHARC Processor Hardware Reference
9-67
Serial Ports
Data-direction programmability is supported in Standard DSP Standard
Serial, Left-justified Sample Pair, and I
2
S modes. The value of the
SPTRAN
bit in
SPCTLx
(0 =
RX
, 1 =
TX
) determines whether the receive or transmit
register for the SPORT becomes active.
The SPORT DMA channels are assigned higher priority than all other
DMA channels (for example, the SPI port and the parallel port) because of
their relatively low service rate and their inability to hold off incoming
data. Having higher priority causes the SPORT DMA transfers to be per-
formed first when multiple DMA requests occur in the same cycle.
Although the DMA transfers are performed with 32-bit words, serial ports
can handle word sizes from 3 to 32 bits, with 8 to 32 bits for I
2
S mode. If
serial words are 16 bits or smaller, they can be packed into 32-bit words
for each DMA transfer. DMA transfers are configured using the
PACK
bit
in the
SPCTLx
Control registers. When serial port data packing is enabled
Table 9-8. Serial Port DMA Channels
Channel
Data Buffer
Description
Priority
0
RXSP1A/TXSP1A
SPORT1 A data
Highest
1
RXSP1B/TXSP1B
SPORT1 B data
2 RXSP0A/TXSP0A
SPORT0
A
data
3
RXSP0B/TXSP0B
SPORT0 B data
4 RXSP3A/TXSP3A
SPORT3
A
data
5
RXSP3B/TXSP3B
SPORT3 B data
6 RXSP2A/TXSP2A
SPORT2
A
data
7
RXSP2B/TXSP2B
SPORT2 B data
8 RXSP5A/TXSP5A
SPORT5
A
data
9
RXSP5B/TXSP5B
SPORT5 B data
10 RXSP4A/TXSP4A
SPORT4
A
data
11
RXSP4B/TXSP4B
SPORT4 B data
Lowest
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...