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Functional Description
5-46
ADSP-BF537 Blackfin Processor Hardware Reference
When all DMA channels’ traffic is taken in the aggregate:
• Transfers between the peripherals and the DMA unit have a maxi-
mum rate of one 16-bit transfer per system clock.
• Transfers between the DMA unit and internal memory (L1) have a
maximum rate of one 16-bit transfer per system clock.
• Transfers between the DMA unit and external memory have a
maximum rate of one 16-bit transfer per system clock.
Some considerations which limit the actual performance include:
• Accesses to internal or external memory which conflict with core
accesses to the same memory. This can cause delays, for example,
for accessing the same L1 bank, for opening/closing SDRAM
pages, or while filling cache lines.
• Each direction change from
RX
to
TX
on the DAB bus imposes a
one
SCLK
cycle delay.
• Direction changes on the DCB bus (for example, write followed by
read) to the same bank of internal memory can impose delays.
• Direction changes (for example, read followed by write) on the
DEB bus to external memory can each impose a several-cycle delay.
• MMR accesses to DMA registers other than
DMAx_CONFIG, DMAx_
IRQ_STATUS
, or
DMAx_PERIPHERAL_MAP
stalls all DMA activity for
one cycle per 16-bit word transferred. In contrast, MMR accesses
to the control/status registers do not cause stalls or wait states.
• Reads from DMA registers other than control/status registers use
one PAB bus wait state, delaying the core for several core clocks.
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 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 ...