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Interface Overview
2-10
ADSP-BF537 Blackfin Processor Hardware Reference
DAB, DCB, and DEB Performance
The processor DAB supports data transfers of 16 bits or 32 bits. The data
bus has a 16-bit width with a maximum frequency as specified in the pro-
cessor data sheet.
The DAB has a dedicated port into L1 memory. No stalls occur as long as
the core access and the DMA access are not to the same memory bank (4K
byte size for L1). If there is a conflict, DMA is the highest priority
requester, followed by the core.
Note that a locked transfer by the core processor (for example, execution
of a
TESTSET
instruction) effectively disables arbitration for the addressed
memory bank or resource until the memory lock is deasserted. DMA con-
trollers cannot perform locked transfers.
DMA access to L1 memory can only be stalled by an access already in
progress from another DMA channel. Latencies caused by these stalls are
in addition to any arbitration latencies.
L
The core processor and the DAB must arbitrate for access to exter-
nal memory through the EBIU. This additional arbitration latency
added to the latency required to read off-chip memory devices can
significantly degrade DAB throughput, potentially causing periph-
eral data buffers to underflow or overflow. If you use DMA
peripherals other than the memory DMA controller, and you target
external memory for DMA accesses, you need to carefully analyze
your specific traffic patterns. Make sure that isochronous peripher-
als targeting internal memory have enough allocated bandwidth
and the appropriate maximum arbitration latencies.
External Access Bus (EAB)
The EAB provides a way for the processor core to directly access off-chip
memory.
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 ...