Programming Model
7-54
ADSP-BF50x Blackfin Processor Hardware Reference
user may choose to write all the MMR registers directly from software,
ending with the write to the
DMAx_CONFIG
register.
The simplest way to signal completion of DMA is by an interrupt. This is
selected by the
DI_EN
bit in the
DMAx_CONFIG
register, and by the necessary
setup of the system interrupt controller. If no interrupt is desired, the soft-
ware can poll for completion by reading the
DMAx_IRQ_STATUS
register and
testing the
DMA_RUN
bit. If this bit is zero, the buffer transfer has
completed.
Continuous Transfers Using Autobuffering
If a peripheral’s DMA data consists of a steady, periodic stream of signal
data, DMA autobuffering (
FLOW
= 1) may be an effective option. Here,
DMA is transferred from or to a memory buffer with a circular addressing
scheme, using either one- or two-dimensional indexing with zero proces-
sor and DMA overhead for looping. Synchronization options include:
• 1-D interrupt-driven—software is interrupted at the conclusion of
each buffer. The critical design consideration is that the software
must deal with the first items in the buffer before the next DMA
transfer, which might overwrite or re-read the first buffer location
before it is processed by software. This scheme may be workable if
the system design guarantees that the data repeat period is longer
than the interrupt latency under all circumstances.
• 2-D interrupt-driven (double buffering)—the DMA buffer is parti-
tioned into two or more sub-buffers, and interrupts are selected
(set
DI_SEL
= 1 in
DMAx_CONFIG
) to be signaled at the completion of
each DMA inner loop. In this way, a traditional double buffer or
“ping-pong” scheme can be implemented.
Содержание EZ-KIT Lite ADSP-BF506F
Страница 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 132: ...Unique Information for the ADSP BF50x Processor 4 22 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 342: ...Unique Information for the ADSP BF50x Processor 7 106 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 484: ...Unique Information for the ADSP BF50x Processor 10 60 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 493: ...ADSP BF50x Blackfin Processor Hardware Reference 11 9 Core Timer Unique Information for the ADSP BF50x Processor None ...
Страница 494: ...Unique Information for the ADSP BF50x Processor 11 10 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 506: ...Unique Information for the ADSP BF50x Processor 12 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 544: ...Unique Information for the ADSP BF50x Processor 13 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 712: ...Unique Information for the ADSP BF50x Processor 16 62 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 972: ...Unique Information for the ADSP BF50x Processor 20 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...