SPI Data Transfer Operations
10-18
ADSP-2126x SHARC Processor Hardware Reference
3. Write to the
SPIDMAC
register to enable the SPI DMA engine and
configure:
• A receive access (
SPIRCV
= 1) or
• A transmit access (
SPIRCV
= 0)
If DMA chaining is desired, set the
SPICHEN
bit in the
SPIDMAC
register.
Enable the SPI port before enabling DMA to avoid data
corruption.
Slave Transfer Preparation
When enabled as a slave, the device prepares for a new transfer according
to the function and actions described in
.
The following steps illustrate the SPI receive or transmit DMA sequence
in an SPI slave in response to a master command:
1. Once the slave-select input is active, the processor starts receiving
and transmitting data on active
SPICLK
edges. The data for one
channel (
TX
or
RX
) is automatically transferred to/from memory by
the IOP. The function of the other channel is dependant on the
GM
and
SENDZ
bits in the
SPICTL
register.
2. Reception or transmission continues until the SPI DMA word
count register transitions from 1 to 0.
3. A number of conditions can occur while the processor is configured
for Slave mode:
• If the DMA engine cannot keep up with the receive data
stream during receive operations, the receive buffer operates
according to the state of the
GM
bit in the
SPICTL
register.
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 ...