Dma Transfers - Analog Devices ADSP-2106x SHARC User Manual

8 Host Interface
8.4.2

DMA Transfers

The host processor can also set up DMA transfers to and from the
ADSP-2106x. Once the host has gained control of the ADSP-2106x, it
can access the on-chip DMA control and parameter registers to set up
an external port DMA operation. This is the most efficient way to
transfer blocks of data.
• DMA Transfers to Internal Memory. The host can set up external port
DMA channels to transfer data to and from ADSP-2106x internal
memory.
• DMA Transfers to External Memory. The host can set up an external
port DMA channel to transfer data directly to external memory using
the DMA request and grant lines (
Refer to the DMA chapter of this manual for details on setting up DMA
operations.
8.4.2.1 DMA Transfers To Internal Memory
The host can set up external port DMA channels to transfer blocks of
data to and from ADSP-2106x internal memory. To set up the DMA
transfer, the host must initialize the ADSP-2106x's control and
parameter registers for that channel. Once the DMA channel is set up,
the host may simply read from (or write to) the corresponding EPBx
buffer. If the buffer is empty (or full), the access is extended until data
is available (or stored). This method allows fast and efficient data
transfers.
If packing and unpacking of DMA data is desired, the packing mode
must be selected in the PMODE bits of the external port DMA control
registers (DMAC6, DMAC7, DMAC8, and DMAC9). Either 16-to-32,
16-to-48, or 32-to-48 bit packing/unpacking can be selected. The
external host bus width indicated by the host packing mode bits
(HPM) in SYSCON must correspond to the external word width
selected by the PMODE bits.
The host may also use the
DMA transfer, but not when
bus.
8 – 20
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DMAR DMAG
x,
DMAR DMAG
x/ x handshake signals for a
HBR
has been used to gain control of the
x).