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Linking EDMA Transfers
Table 6–5. Link Conditions
6-26
The link address is evaluated only if LINK is equal to 1 and only after the event
parameters have been exhausted. An event's parameters are exhausted
when the EDMA controller has completed the transfer associated with the re-
quest. Table 6–5 shows the conditions when the linking of parameters is per-
formed. The link conditions for a 2-D transfer is different from a non-2D transfer
and it also depends on the type of synchronization chosen. Since the EDMA
parameter RAM is 2048 bytes, it allows up to 69 reload entries in addition to
the 16 EDMA event parameter entries (see section 6.5). There is virtually no
limit to the length of linked transfers. However, the last transfer parameter
entry should have its LINK = 0 so that the linked transfer stops after the last
transfer.
LINK = 1
Read/write sync
(FS = 0)
Frame sync (FS = 1)
Once the link conditions are met for an event, the transfer parameters located
at the link address are loaded into one of the 16 EDMA channel/event parame-
ter space for the corresponding event. Now, the EDMA is ready to start the next
transfer. To eliminate possible timing windows posed during this parameter re-
load mechanism, the EDMA controller does not evaluate the event register
during this time. However, events are still captured in the ER, and will be
processed after the parameter reload is complete.
Non-2D Transfers
Frame count == 0 &&
Element count == 1
Frame count == 0
2D Transfers
Frame count == 0
Always
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