Texas Instruments OMAP5912 Reference Manual page 676

Multimedia processor device overview and architecture

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Table 21. Packing and Splitting Summary

Direct Memory Access (DMA) Support

Burst 4x32 bits if bursting is enabled and the accessed source or

destination port supports it. Software can enable or disable bursting with

the bit-fields SRC_BURST_EN and DST_BURST_EN in the DMA_CSDP

bursting and hence, result in single accesses.

Table 21 summarizes the possible transfer configurations and shows the

cases where packing and splitting are performed.

Port Access Capability

To compute the type of an access (8/16/32-bit or 4x32-bit burst) and decide

to pack consecutive accesses, an address calculation unit checks:

Its related DMA port capabilities:

Can the port perform bytes, 16-bit, or 32-bit access?

Can the port perform 4x32-bit burst access?

What is allowed by the software in the configuration registers:

Is packing allowed?

Is bursting allowed?

The last bits of the address:

Is the address even or odd?

Is the address word16, word32, 4x32-bit burst aligned?

The number of elements remaining in the frame

The synchronized transfer type for the LCh

The restrictions for packing and bursting are as follows:

Constant address mode automatically disables packing and bursting on

the DMA source or destination port where it is used. The other end of the

DMA channel can still utilize packing and bursting if that DMA port is not

configured to use constant address mode.

Packing / Splitting

pack 2 x s8 => 16

pack 4 x s8 => 32

split s16 => 2 x 8

pack 2x s16 => 32

split s32 => 4 x 8

split s32 => 2 x 16

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