Addressing Modes - Texas Instruments OMAP5912 Reference Manual

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Table 128. DSP DMA DMA_CCR.AUTOINIT, END_PROG and REPEAT Bit Effects

END_PROG REPEAT

Addressing Modes

The following registers are part of the working set and are accessible to the

user. They always have an effect on the current transfer.

An error can occur if the CPU accesses a channel to program it while it is

reloading. To avoid this error, the CPU can use the DMA_CCR.END_PROG

bit as follows:

The CPU must set the bit to 1 once the channel setup is finished.

The DMA clears the bit when the programming set of registers is loaded

in the working set of registers.

When a transfer finishes, the DMA channel waits until END_PROG is 1 before

proceeding to reload. Once the reload is done, the DMA clears the

END_PROG bit.

DMA_CCR.REPEAT bit can disable the effect of the END_PROG bit on the

reload behavior. If this bit is set to 1, the DMA channel always reloads its

working set of registers, whatever the END_PROG value is. Table 128

describes the effects of the DMA_CCR.AUTOINIT, END_PROG, and

REPEAT bits.

Autoinitialization Behavior

No autoinitialization.

At the end of current transfer, the channel waits until end prog = 1

to load the programming register set to its working register set.

At the end of current transfer, channel immediately loads the

programming register set in its working register set.

The DMA has four addressing modes: Constant, post-incremented, indexed,

and double-indexed.

The amount of data (block size) to transfer is programmed in bytes. This size

can be odd or even.

Direct Memory Access (DMA) Support

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