ADSP-2126x SHARC Processor Hardware Reference
10-19
Serial Peripheral Interface Port
• If
GM
= 0 and the DMA buffer is full, the incoming data is
discarded, and the
RXSPI
register is not updated. While per-
forming a receive DMA, the transmit buffer is assumed to
be empty. If
SENDZ
= 1, the device repeatedly transmits
zero’s on the
MOSI
pin. If
SENDZ
= 0, it repeatedly transmits
the contents of the
TXSPI
register.
• If
GM
= 1 and the DMA buffer is full, the device continues to
receive new data from the
MISO
pin, overwriting the older
data in the DMA buffer.
• If the DMA engine cannot keep up with the transmit data
stream during a transmit operation because another DMA
engine has been granted the bus (or for another reason), the
transmit port operates according to the state of the
SENDZ
bit
in the
SPICTL
register.
If
SENDZ
= 1 and the DMA buffer is empty, the device
repeatedly transmits zero’s on the
MOSI
pin. If
SENDZ
= 0 and
the DMA buffer is empty, it repeatedly transmits the last
word it transmitted before the DMA buffer became empty.
All aspects of SPI receive operation should be ignored. The
data in the
RXSPI
register is not intended to be used, and the
RXS
and
ROVF
bits should be ignored. The
ROVF
overrun con-
dition cannot generate an error interrupt in this mode.
While a DMA transfer may be used on one channel (
TX
or
RX
), the
core, (based on the
RXS
and
TXS
status bits), can transfer data in the
other direction.
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...