Analog Devices VisualDSP++ 5.0 Service Manual page 256

Theory of Operation
• The
YCount
contained within the whole buffer.
• The
YModify
When using the circular mode, the
called prior to enabling dataflow on the channel. After enabling dataflow,
if the client wants to change to a different circular buffer, the client must
first disable dataflow on the channel, call the
with the new buffer data, and then re-enable dataflow on the appropriate
channel.
ONE
CONTIGUOUS
BUFFER
Figure 6-1. Circular Buffer Usage in a Circular Transfer
Large Descriptor Chaining Model
The large descriptor chaining model (
allows the client to create chains of descriptors, residing anywhere in
memory, where each descriptor describes a specific work unit.
Using the large descriptor chaining mode, the client provides the DMA
manager with one or more descriptor chains, as shown in
6-16
value. Set this parameter to the number of sub-buffers
value. This parameter is ignored.
adi_dma_Buffer()
SUB-BUFFER 0
SUB-BUFFER 1
. . .
SUB-BUFFER N
CALLBACK ON SUB-BUFFER COMPLETE
CALLBACK ON ENTIRE BUFFER COMPLETE
VisualDSP++ 5.0 Device Drivers and System
Services Manual for Blackfin Processors
function must be
adi_dma_Buffer()
ADI_DMA_MODE_DESCRIPTOR_LARGE
function
)
Figure 6-2.