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.
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 ...