Ameba-D User Manual
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Fig 9-9 Single transaction
Fig 9-10 shows a burst transaction, followed by two back-to-back single transactions, where the hclk frequency is twice the per_clk frequency;
handshaking interface 0 is used. After the first burst transaction, the peripheral enters the Single Transaction Region and the DMAC starts
sampling dma_single[0]. On hclk edges T2 and T4, the DMAC samples that dma_single[0] is asserted and performs single transactions. The
second single transaction terminates the block transfer; dma_finish[0] is asserted to indicate block completion.
Fig 9-10 Burst followed by Back-to-Back single transactions
In the Single Transaction Region, if an active level on dma_req and dma_single occur on the same cycle – or if the active level on dma_single
occurs only one cycle before an active level on dma_req – then the burst transaction takes precedence over the single transaction, and the
block would be completed using an Early-Terminated Burst Transaction. If the DMAC samples that dma_req[0] was asserted on hclk cycles T1-
T2 or T3-T4 in Fig 9-10, then the burst request takes precedence.
In Fig 9-11, an active level on dma_req[0] after time T4 takes precedence over the active level on dma_single[0] after time T3.
Fig 9-11 Early-Terminated burst transaction
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2019-05-15 10:08:03