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Src/Dst Address Updates
6.12 Src/Dst Address Updates
Depending on the SUM/DUM fields in the options word of EDMA transfer pa-
rameters, the source and/or destination addresses can be modified. The
EDMA controller performs the necessary address computation. The various
address update modes listed in Table 6–3 provide for a variety of data struc-
tures that can be created. The source and/or destination address is updated
depending on whether frame sync is enabled or not, or 2D transfer is selected
or not. All address updates should occur after the current transfer request is
sent. Therefore, these updates are used to set the EMDA parameters for the
next event.
The update of the source or destination address depends on the transfer type
chosen for both the source and destination. For example, a transfer from
non-2D source to a 2D destination requires that the source be updated on a
frame basis (not on element basis) to provide 2D type data to the destination.
Table 6–7 shows the amount by which the source address is modified for each
of the combinations of FS, 2DD/2DS, and SUM parameters. Table 6–8 shows
the destination address updates that are possible.
Note that when either the source or the destination is a 2D transfer and the
transfer is frame synchronized, it means that the complete block of data is
transferred on a frame sync event. Therefore, address updates are not
applicable in this case. If LINK = 1 and the link conditions outlined in Table 6–5
are met, no address updates occur. Instead, the link parameters are copied
directly to the event parameter.
EDMA Controller
6-29
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