Autoinitialization Configuration Bits Summary; Addressing Modes - Texas Instruments OMAP5910 Technical Reference Manual

Table 5–3. Autoinitialization Configuration Bits Summary
AUTOINIT END_PROG
0 x
1 0
1 1
1 x
5.3.1.6 Priorities Between Channels
5.3.2

Addressing Modes

To avoid the reload of a configuration when the MPU programs the channel,
the MPU can use the autoinitialization bits of the DMA_CCR register, which are
described in Table 5–3.
REPEAT Autoinitialization Behavior
x No autoinitialization
0 At the end of current transfer, channel waits until END_PROG = 1
to load the programming register set in its working register set.
At the end of current transfer, channel immediately loads the
0
programming register set in its working register set. programming register set in its working register set
1
Each channel can be given a low- or high-priority level. When a DMA port
receives requests from several channels, it looks at their priorities:
-
Requests from high-priority channels are served first.
-
Requests from low-priority channels are served only if there are no
requests from high-priority channels on the port. This can occur if there are
no high-priority channels activated, if the high-priority channels are stalled
(by a slow source or destination), or if the high-priority channels are
waiting for a synchronization event.
-
Requests of the same priority level are served in a round-robin manner
(time division multiplex).
Figure 5–6 provides an example of address index management. In this
example, Element Size = 4, Element Index = 3, Frame Size = 2, and
Frame Index = 5.
An addressing mode is an address computation algorithm a DMA channel can
use to know where to access data. The system DMA has four addressing
modes: constant, post-incremented, indexed, and double-indexed.
Generic Channels
System DMA Controller 5-13