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Interface Overview
2-8
ADSP-BF537 Blackfin Processor Hardware Reference
DMA Access Bus (DAB), DMA Core Bus (DCB), DMA
External Bus (DEB)
The DAB, DCB, and DEB buses provide a means for DMA-capable
peripherals to gain access to on-chip and off-chip memory with little or no
degradation in core bandwidth to memory.
DAB Arbitration
Sixteen DMA channels and bus masters support the DMA-capable periph-
erals in the processor system. The twelve peripheral DMA channel
controllers can transfer data between peripherals and internal or external
memory. Both the read and write channels of the dual-stream memory
DMA controller access their descriptor lists through the DAB.
The DCB has priority over the core processor on arbitration into L1 con-
figured as SRAM. For off-chip memory, the core (by default) has priority
over the DEB for accesses to the EPB. The processor has a programmable
priority arbitration policy on the DAB.
shows the default arbi-
tration priority. In addition, by setting the
CDPRIO
bit in the
EBIU_AMGCTL
register, all DEB transactions to the EPB have priority over core accesses
to external memory. Use of this bit is application-dependent. For exam-
ple, if you are polling a peripheral mapped to asynchronous memory with
long access times, by default the core will “win” over DMA requests. By
setting the
CDPRIO
bit, the core would be held off until DMA requests
were serviced.
Содержание Blackfin ADSP-BF537
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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 ...
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Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
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Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...