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ADSP-BF537 Blackfin Processor Hardware Reference
5-37
Direct Memory Access
stream into work units on its own, perhaps as a result of parsing the
data currently passing though its supported communication chan-
nel, without direct real-time control by the processor.
If a channel programmed for transmit (memory read) receives a
finish control command, the channel momentarily pauses while
any pending memory reads initiated prior to the finish command
are completed. During this period of time, the channel does not
grant DMA requests. Once all pending reads have been flushed
from the channel’s pipelines, the channel signals an interrupt (if
enabled), and begins fetching the next descriptor (if any). DMA
data requests from the peripheral are granted as soon as new
prefetched data is available in the DMA FIFO.
If a channel programmed for receive (memory write) receives a fin-
ish control command, the channel stops granting new DMA
requests while it drains its FIFO. Any DMA data received by the
DMA Controller prior to the finish command is written to mem-
ory. When the FIFO reaches an empty state, the channel signals an
interrupt (if enabled) and begins fetching the next descriptor (if
any). Once the next descriptor has been fetched, the channel ini-
tializes its FIFO, and then resumes granting DMA requests from
the peripheral.
•
Request Data
The request data control command is identical to the DMA request
operation of peripherals which are not DMA-management-capable.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...