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ADSP-BF537 Blackfin Processor Hardware Reference
5-55
Direct Memory Access
This type of traffic control represents a trade-off of latency to improve uti-
lization (efficiency). Higher traffic timeouts might increase the length of
time each request waits for its grant, but it often dramatically improves the
maximum attainable bandwidth in congested systems, often to above
90%.
To disable preferential DMA prioritization, program the
DMA_TC_PER
reg-
ister to
0x0000
.
Programming Model
Several synchronization and control methods are available for use in devel-
opment of software tasks which manage peripheral DMA and memory
DMA (see also
able to accept requests for new DMA transfers from other software tasks,
integrate these transfers into existing transfer queues, and reliably notify
other tasks when the transfers are complete.
In the processor, it is possible for each peripheral DMA and memory
DMA stream to be managed by a separate task or to be managed together
with any other stream. Each DMA channel has independent, orthogonal
control registers, resources, and interrupts, so that the selection of the
control scheme for one channel does not affect the choice of control
scheme on other channels. For example, one peripheral can use a
linked-descriptor-list, interrupt-driven scheme while another peripheral
can simultaneously use a demand-driven, buffer-at-a-time scheme syn-
chronized by polling of the
DMAx_IRQ_STATUS
register.
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 ...