
Programming Model
15-38
ADSP-214xx SHARC Processor Hardware Reference
With SPI enabled:
1. Disable DMA and clear the DMA FIFO by
FIFOFLSH
bit in the
SPIDMACx
register. This ensures that any data from a previous DMA
operation is cleared before configuring a new DMA operation.
2. Clear the
RXSPIx
/
TXSPIx
registers and the buffer status without dis-
abling SPI. This can be done by ORing 0xC0000 with the present
value in the
SPICTLx
registers. Use the
RXFLSH
and
TXFLSH
bits to
clear the
RXSPIx
/
TXSPIx
registers and the buffer status.
3. Clear all errors by writing to the W1C-type bits in the
SPISTAT
register. This ensures that error bits
SPIOVF
and
SPIUNF
in the
SPIDMACx
registers are cleared when a new DMA is configured.
4. Reconfigure the
SPICTL
register to remove the clear condition on
the
RXSPI
/
TXSPI
register bits.
5. Configure DMA by writing to the DMA parameter registers and
the
SPIDMACx
register.
Multi-Master Transfers
The following steps show how to implement a system with two SPI
devices. Since the slaves cannot initiate transfers over the bus, the master
must send frames over the
MOSI
pin. This ensures that slaves can respond
to the bus by sending messages over the
MISO
pin to the bus master.
1. Slave writes message to its
MISO
pin.
2. Slave starts polling its
SPI_DS_I
pin which is currently low.
3. Message is latched by current master and decoded.
4. Master deasserts the slave select signal and clears the
SPIMS
bit to
become a slave.
www.BDTIC.com/ADI
Summary of Contents for SHARC ADSP-214 Series
Page 60: ...Contents lx ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 290: ...Programming Model 4 26 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 656: ...Programming Model 15 40 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Page 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...