SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
In a AB-synchronized transfer, each EDMA sync event initiates the transfer of 2 dimensions or one frame. Each event/TR packet conveys information for one entire frame of BCNT_n arrays of ACNT_n bytes. Thus, EDMA_TPCC_CCNT_n events are needed to completely service a PaRAM set.
Arrays are always separated by EDMA_TPCC_BIDX_n[15:0] SBIDX and EDMA_TPCC_BIDX_n[31:16] DBIDX as shown in Figure 18-20. Frames are always separated by SRCCIDX and DSTCIDX.
Note that for AB-synchronized transfers, after a TR for the frame is submitted, the address update is to add EDMA_TPCC_CIDX_n[15:0] SCIDX / EDMA_TPCC_CIDX_n[31:16] DCIDX to the beginning address of the beginning array in the frame. This is different from A-synchronized transfers where the address is updated by adding SRCCIDX/DSTCIDX to the start address of the last array in the frame. See Section 18.2.4.3.6 Parameter Set Updates for details on parameter set updates.
Figure 18-20 shows an AB-synchronized transfer of 3 (CCNT) frames of 4 (BCNT) arrays of n (ACNT) bytes. In this example, a total of 3 sync events (CCNT) exhaust a PaRAM set; that is, a total of 3 transfers of 4 arrays each completes the transfer.
ABC-synchronized transfers are not directly supported. It can be logically achieved by chaining between multiple AB-synchronized transfers.
VCP does not support Const/FIFO mode DMA transfers. The EDMA should be configured for AB-Synchronized transfer with ACNT = 8, BCNT = number of elements.