Analog Devices VisualDSP++ 5.0 Service Manual page 254

Theory of Operation
• The
YCount
transfers. For two-dimensional transfers, the value represents the
outer loop count (number of rows).
• The
YModify
transfers. For two-dimensional transfers, this value defines the
outer loop address increment/decrement (stride) that is applied
after each inner loop completion. This value is the offset between
the last element of one row and the first element of the next row.
Regardless of whether dataflow on the channel is enabled, the
adi_dma_Buffer()
is already enabled on the channel, the DMA manager begins executing the
transfer; otherwise, the transfer does not begin until the dataflow is
enabled via the
single-transfer mode, the
time, as long as a transfer on the channel is not already in progress.
Circular Transfers
The circular transfer mode (
buffer capability of the DMA controller. Using the circular transfer mode,
the client provides the DMA manager with a single contiguous buffer
comprising n sub-buffers, as shown in
When dataflow is enabled, the DMA manager begins transferring data at
the start of the buffer, continuing on throughout the entire buffer, and
then automatically looping back to the top of the buffer again, repeating
indefinitely. Optionally, the client can direct the DMA manager to
generate callbacks at the completion of each sub-buffer, to generate call-
backs at the completion of the entire buffer, or not to generate callbacks.
6-14
value. This parameter is ignored for one-dimensional
value. This parameter is ignored for one-dimensional
function returns immediately to the caller. If dataflow
adi_dma_Control()
adi_dma_Buffer()
ADI_DMA_MODE_CIRCULAR
VisualDSP++ 5.0 Device Drivers and System
function. When using the
function can be called at any
) leverages the auto-
Figure 6-1 on page
Services Manual for Blackfin Processors
6-16.