ADSP-214xx SHARC Processor Hardware Reference
15-19
Serial Peripheral Interface Ports
in the registers are zeros. This code works only if the
MSBF
bit is zero in
both the transmitter and receiver, and the
SPICLK
frequency is less. If
MSBF
= 1 in the transmitter and receiver, and
SPICLK
has a lower frequency, the
received words follow the order 0x12, 0x34, 0x56, 0x78.
16-bit word.
When transmitting, the SPI port sends out only the lower 16
bits of the word written to the SPI buffer. When receiving, the SPI port
packs the 16-bit word to the lower 32 bits of the
RXSPI
buffer while the
upper bits in the register are zeros.
32-bit word.
No packing of the
RXSPI
or
TXSPI
registers is necessary as the
entire 32-bit register is used for the data word.
Core Buffer Status
For core access to SPI, master and slave mode operates different:
1. If core access to a SPI slave is unable to keep up with the trans-
mit/receive stream during a transfer operation (because of an
interrupt or any other reason) the SPI operates according to the
states of the
SENDZ
and
GM
bits in the
SPICTLx
register.
• If
SENDZ
= 1 and the transmit buffer is empty, the device
repeatedly transmits zeros on the
MOSI
pin. One word is
transmitted for each new transfer initiate command.
• If
SENDZ
= 0 and the transmit buffer is empty, the device
repeatedly transmits the last word transmitted before the
transmit buffer became empty.
• If
GM
= 1 and the receive buffer is full, the device continues
to receive new data from the
MISO
pin, overwriting the older
data in the
RXSPI
buffer.
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Содержание SHARC ADSP-214 Series
Страница 60: ...Contents lx ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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...