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ADSP-2126x SHARC Processor Hardware Reference
10-31
Serial Peripheral Interface Port
For example, if the processor executes the following instructions, the SPI
port transmits
0x5678
.
r0 = 0x12345678
dm(TXSPI) = r0;
When receiving, the SPI port packs the 16-bit word to the lower 32 bits of
the
RXSPI
buffer while the upper bits in the register are zeros.
For example, if an SPI host sends the processor the 32-bit word
0x12345678
, the processor receives the following words:
0x00005678 //first word
0x00001234 //second word
32-Bit Word Lengths
Thirty-two bit word lengths can be used when transmitting or receiving.
No packing of the
RXSPI
or
TXSPI
registers is necessary as the entire 32-bit
register is used for the data word.
Packing
In order to communicate with 8-bit SPI devices and store 8-bit words in
internal memory, a packed transfer feature is built into the SPI port. Pack-
ing is enabled through the
PACKEN
bit in the
SPICTL
register. The SPI is
unpacks data when it transmits and packs data when it receives. When
packing is enabled, two 8-bit words are packed into one 32-bit word.
When the SPI port is transmitting, two eight-bit words are packed into
one 32-bit word. When receiving, words are unpacked from one 32-bit
word into two eight-bit words.
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 ...