Programming Model
15-34
ADSP-214xx SHARC Processor Hardware Reference
receive DMA the status bit is asserted when the DMA count becomes
zero. For transmit DMA the
SPIFE
goes high when:
• the DMA count becomes zero and
• the DMA FIFO becomes empty and
• the
SPITX
buffer becomes empty (
TXS
bit high) and
• transfer is complete (
SPIF
bit goes high)
Note that the
SPIFE
bit can go high between two DMA blocks of a
chained DMA.
Switching From Transmit to a New DMA
The following sequence details the steps for switching from transmit to
transmit/receive DMA.
With SPI disabled:
1. Poll the
SPIFE
bit in the
SPISTAT
register. If this bit is high the SPI
can be disabled.
2. Clear the
SPICTLx
register to disable the SPI. Disabling the SPI also
clears the
RXSPIx
/
TXSPIx
buffer and the buffer status.
3. Disable DMA by clearing the
SPIDMACx
register.
4. Clear all errors by writing to the W1C-type bits in the
SPISTATx
registers. This ensures that no interrupts occur due to errors from a
previous DMA operation.
5. Reconfigure the
SPICTLx
register and enable the SPI ports.
6. Configure DMA by writing to the DMA parameter registers and
the
SPIDMACx
registers using the
SPIDEN
bit (bit 0).
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Содержание SHARC ADSP-214 Series
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Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...