ADSP-2126x SHARC Processor Hardware Reference
10-45
Serial Peripheral Interface Port
4. The reception or transmission continues until
SPIDS
is released or
until the slave has received the proper number of clock cycles.
5. The slave device continues to receive or transmit with each new
falling-edge transition on
SPIDS
or active
SPICLK
clock edge.
If the transmit buffer remains empty, or the receive buffer remains full,
the devices operate according to the states of the
SENDZ
and
GM
bits in the
SPICTLx
registers.
• If
SENDZ
= 1 and the transmit buffer is empty, the device repeatedly
transmits zero’s on the
MISO
pin.
• If
SENDZ
= 0 and the transmit buffer is empty, it repeatedly trans-
mits 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
MOSI
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
RXSPIx
registers are not updated.
Master Mode DMA Transfers
To configure the SPI port for master mode DMA transfers:
1. Specify which
FLAG
pins to use as the slave-select signals by setting
one or more of the
DSxEN
bits (bits 3–0) in the SPI flag (
SPIFLGx
)
registers.
2. Enable the device as a master and configure the SPI system by
selecting the appropriate word length, transfer format, baud rate,
and so on in the
SPIBAUDx
and
SPICTLx
registers. The
TIMOD
field
(bits 1–0) in the
SPICTLx
registers is configured to select transmit
or receive with DMA mode (
TIMOD
= 10).
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 ...