Registers For Controlling The Context Of A Channel - Texas Instruments OMAP5910 Reference Manual

DSP DMA
Figure 68.

Registers for Controlling the Context of a Channel

Configuration registers
(programmed by code)
DMACSDP
DMACCR
DMACICR
DMACSR
DMACSSAL
DMACSSAU
DMACDSAL
DMACDSAU
DMACEN
DMACFN
DMACFI/DMACSFI
DMACEI/DMACSEI
DMACSAC
DMACDAC
DMACDEI
DMACDFI
126 DSP Subsystem
The set of conditions under which transfers occur in a channel is called the
channel context. Each of the six channels contains a register structure for
programming and updating the channel context (see Figure 68). The
programming code modifies the configuration registers. When it is time for
data transferring, the contents of the configuration registers are copied to the
working registers, and the DMA controller uses the working register values to
control channel activity. The copy from the configuration registers to the
working registers occurs whenever the code enables the channel (EN = 1 in
DMACCR). In addition, if the auto-initialization mode is on (AUTOINIT = 1 in
DMACCR), the copy occurs between block transfers. For more information
about the auto-initialization mode, see section 7.2.4.
Some configuration registers can be programmed for the next block transfer
while the DMA controller is still running the current context from the working
registers. The next transfer will use the new configuration without stopping the
DMA controller. The registers DMACSDP, DMACCR, DMACICR, DMACSR,
DMAGCR, DMAGSCR, and DMAGTCR should not be configured in this
manner. Modification of these registers while the DMA channel is running may
cause unpredictable channel operation.
Automatically copied
when channel enabled,
and between block transfers
in auto-initialization mode
Working registers
(used by DMA controller)
DMACSDP copy
DMACCR copy
DMACICR copy
DMACSR copy
DMACSSAL copy
DMACSSAU copy
DMACDSAL copy
DMACDSAU copy
DMACEN copy
DMACFN copy
DMACFI/DMACSFI copy
DMACEI/DMACSEI copy
DMACSAC copy
DMACDAC copy
DMACDEI copy
DMACDFI copy
SPRU890A