Functional Description
7-28
ADSP-BF50x Blackfin Processor Hardware Reference
descriptors), when the DMA channel is paused. The DMA channel pauses
after descriptors with
FLOW
= 0 mode, and may be restarted (for example,
after an interrupt) by writing the channel’s
DMAx_CONFIG
register with
DMAEN
= 1.
If the
SYNC
bit is 0 in the new work unit’s
DMAx_CONFIG
value, a continuous
transition is selected. In this mode, any data items received into the DMA
FIFO while the channel was paused are retained, and they are the first
items written to memory in the new work unit. This mode of operation
provides lower latency at work unit transitions and ensures that no data
items are dropped during a DMA pause, at the cost of certain restrictions
on the DMA descriptors.
If the
SYNC
bit is 0 on the first descriptor of a descriptor chain after
a DMA pause, the DMA word size of the new chain must not
change from the word size of the previous descriptor chain active
before the pause, unless the DMA channel is reset between chains
by writing the
DMAEN
bit to 0 and then to 1 again.
If the
SYNC
bit is 1 in the new work unit’s
DMAx_CONFIG
value, a synchro-
nized transition is selected. In this mode, only the data received from the
peripheral by the DMA channel after the write to the
DMAx_CONFIG
register
are delivered to memory. Any prior data items transferred from the
peripheral to the DMA FIFO before this register write are discarded. This
provides direct synchronization between the data stream received from the
peripheral and the timing of the channel restart (when the
DMAx_CONFIG
register is written).
For receive DMAs, the
SYNC
bit has no effect in transitions between work
units in the same descriptor chain (that is, when the previous descriptor’s
FLOW
mode was not 0, so that DMA channel did not pause.)
If a descriptor chain begins with a
SYNC
bit of 1, there is no restriction on
DMA word size of the new chain in comparison to the previous chain.
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 ...