Functional Description
15-8
ADSP-214xx SHARC Processor Hardware Reference
connected to high, as it affects the functioning of certain bits in the
SPICTLx
register.
Functional Description
Each SPI interface contain its own transmit shift (
TXSR
,
TXSRB
) and receive
shift (
RXSR
,
RXSRB
) registers (not user accessible). The
TXSRx
registers seri-
ally transmit data and the
RXSRx
registers receive data synchronously with
the SPI clock signal (
SPICLK
).
shows a block diagram of the
SHARC processor SPI interface. The data is shifted into or out of the shift
registers on two separate pins: the master in slave out (
MISO
) pin and the
master out slave in (
MOSI
) pin.
During data transfers, one SPI device acts as the SPI master by controlling
the data flow. It does this by generating the
SPICLK
and asserting the SPI
device select signal (
SPIDS
). The SPI master receives data using the
MISO
pin and transmits using the
MOSI
pin. The other SPI device acts as the SPI
slave by receiving new data from the master into its receive shift register
using the
MOSI
pin. It transmits requested data out of the transmit shift
register using the
MISO
pin.
Each SPI port contains a dedicated transmit data buffer (
TXSPI
,
TXSPIB
)
and a receive data buffer (
RXSPI
,
RXSPIB
). Transmitted data is written to
TXSPIx
and then automatically transferred into the transmit shift register.
Once a full data word has been received in the receive shift register, the
data is automatically transferred into
RXSPIx
, from which the data can be
read. When the processor is in SPI master mode, programmable flag pins
provide slave selection. These pins are connected to the
SPIDS
of the slave
devices.
The SPI has a single DMA engine which can be configured to support
either an SPI transmit channel or a receive channel, but not both simulta-
neously. Therefore, when configured as a transmit channel, the received
data is essentially ignored. When configured as a receive channel, what is
www.BDTIC.com/ADI
Содержание SHARC ADSP-214 Series
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Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 290: ...Programming Model 4 26 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 656: ...Programming Model 15 40 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...