Data Transfers
15-20
ADSP-214xx SHARC Processor Hardware Reference
• If
GM
= 0 and the receive buffer is full, the incoming data is
discarded, and the
RXSPI
register is not updated.
2. If core access to a SPI master is unable to keep up with the trans-
mit/receive stream during a transfer operation (because of an
interrupt or another reason) the SPI stalls the
SPICLK
until new
data is read/written into the
TXSPI
/
RXSPI
buffers. In this scenario
the
ROVF
/
TUVF
condition bits are set indicating an exception in the
data stream.
DMA Buffer Status
If the DMA engine is unable to keep up with the transmit/receive stream
during a transfer operation because of latency caused by using multiple
DMA channels, 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.
• If
GM
= 0 and the receive buffer is full, the incoming data is dis-
carded, and the
RXSPI
register is not updated.
Core Transfers
The
RXS
bit defines when the receive buffer can be read. The
TXS
bit
defines when the transmit buffer can be filled. The end of a single word
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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...