Single Transfers; Circular Transfers; Large Descriptor Chaining Model; Small Descriptor Chaining Model - Analog Devices VisualDSP++ 5.0 Service Manual

Theory of Operation
After the channel has been successfully opened, the channel can be
configured, buffers can be supplied to the channel, and so on. Note that
the actual transfer of data does not begin with the
function. Dataflow must be enabled specifically via the
function.
The DMA manager supports the following operational modes of the
Blackfin processor's DMA controller:
•

"Single Transfers"

• "Circular Transfers" on page 6-14
• "Large Descriptor Chaining Model" on page 6-16
• "Small Descriptor Chaining Model" on page 6-20
Single Transfers
The single transfer operating mode (
individual, single buffers of data. When using the single transfer mode,
the client calls the
client passes the following parameters to the function:
• The channel handle. This is the value provided to the client during
the
adi_dma_Open()
• The starting address of the buffer. This value is the address in
memory where data is initially read (for outbound data) or the
address in memory where data is initially stored (when the transfer
is for inbound data).
• The configuration word for the transfer. This is a 16-bit value that
represents the DMA configuration control register for the channel.
The DMA manager include file provides macros, that allow the
client to quickly and easily create a configuration word. The fol-
lowing fields within the configuration word are the only fields for
which values must be provided.
6-12
ADI_DMA_MODE_SINGLE
adi_dma_Buffer()
function.
VisualDSP++ 5.0 Device Drivers and System
Services Manual for Blackfin Processors
adi_dma_MemoryOpen
adi_dma_Control
function to schedule a transfer. The
) transfers