
Functional Description
5-22
ADSP-BF59x Blackfin Processor Hardware Reference
Then DMA data transfer operation begins, as shown in
Figure 5-2 on
page 5-19
.
DMA Refresh
On completion of a work unit:
• The DMA controller completes the transfer of all data between
memory and the DMA unit.
• If
SYNC
= 1 and
WNR
= 0 (memory read), the DMA controller selects
a synchronized transition and transfers all data to the peripheral
before continuing.
• If enabled by
DI_EN
, the DMA controller signals an interrupt to the
core and sets the
DMA_DONE
bit in the channel’s
DMAx_IRQ_STATUS
register.
• If
FLOW
= 0 the DMA controller stops operation by clearing the
DMA_RUN
bit in
DMAx_IRQ_STATUS
register after all data in the chan-
nel’s DMA FIFO has been transferred to the peripheral.
• During the fetch in
FLOW
modes 4, 6, and 7, the DMA controller
sets the
DFETCH
bit in
DMAx_IRQ_STATUS
register to 1. At this point,
the DMA operation depends on whether
FLOW
= 4, 6, or 7, as fol-
lows:
If
FLOW
= 4 (descriptor array) the DMA controller loads a new
descriptor from memory into the DMA registers using the contents
of
DMAx_CURR_DESC_PTR
, and increments
DMAx_CURR_DESC_PTR
. The
descriptor size comes from the
NDSIZE
field of the
DMAx_CONFIG
reg-
ister prior to the beginning of the fetch.
If
FLOW
= 6 (small descriptor list) the DMA controller copies the
32-bit
DMAx_NEXT_DESC_PTR
into
DMAx_CURR_DESC_PTR
. Next, the
DMA controller fetches a descriptor from memory into the DMA
Содержание ADSP-BF59x Blackfin
Страница 64: ...Development Tools 1 22 ADSP BF59x Blackfin Processor Hardware Reference...
Страница 74: ...Processor Specific MMRs 2 10 ADSP BF59x Blackfin Processor Hardware Reference...
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Страница 244: ...Programming Examples 6 40 ADSP BF59x Blackfin Processor Hardware Reference...
Страница 345: ...ADSP BF59x Blackfin Processor Hardware Reference 9 9 Core Timer Unique Information for the ADSP BF59x Processor None...
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Страница 700: ...Programming Examples 16 78 ADSP BF59x Blackfin Processor Hardware Reference...
Страница 738: ...Boundary Scan Architecture B 8 ADSP BF59x Blackfin Processor Hardware Reference...