ADSP-BF50x Blackfin Processor Hardware Reference
7-11
Direct Memory Access
Stop Mode
In stop mode, the DMA operation is executed only once. When started,
the DMA channel transfers the desired number of data words and stops
itself when the transfer is complete. If the DMA channel is no longer used,
software should clear the
DMAEN
enable bit to disable the otherwise paused
channel. Stop mode is entered if the
FLOW
bit field in the DMA channel’s
DMAx_CONFIG
register is 0. The
NDSIZE
field must always be 0 in this mode.
For receive (memory write) operation, the
DMA_RUN
bit functions almost
the same as the inverted
DMA_DONE
bit. For transmit (memory read) opera-
tion, however, the two bits have different timing. Refer to the description
of the
SYNC
bit in the
DMAx_CONFIG
register for details.
Autobuffer Mode
In autobuffer mode, the DMA operates repeatedly in a circular manner. If
all data words have been transferred, the address pointer
DMAx_CURR_ADDR
is reloaded automatically by the
DMAx_START_ADDR
value. An interrupt may
also be generated.
Autobuffer mode is entered if the
FLOW
field in the
DMAx_CONFIG
register
is 1. The
NDSIZE
bit must be 0 in autobuffer mode.
Two-Dimensional DMA Operation
Register-based and descriptor-based DMA can operate in one-dimensional
mode or two-dimensional mode.
In two-dimensional (2-D) mode, the DMAx_X_COUNT register is
accompanied by the DMAx_Y_COUNT register, supporting arbitrary
row and column sizes up to 64K × 64K elements, as well as arbitrary
DMAx_X_MODIFY and DMAx_Y_MODIFY values up to ±32K bytes.
Furthermore, DMAx_Y_MODIFY can be negative, allowing implementa-
tion of interleaved datastreams. The DMAx_X_COUNT and
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...